| File: | src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/CodeGenPrepare.cpp |
| Warning: | line 1134, column 37 Called C++ object pointer is null |
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| 1 | //===- CodeGenPrepare.cpp - Prepare a function for code generation --------===// | |||
| 2 | // | |||
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | |||
| 4 | // See https://llvm.org/LICENSE.txt for license information. | |||
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | |||
| 6 | // | |||
| 7 | //===----------------------------------------------------------------------===// | |||
| 8 | // | |||
| 9 | // This pass munges the code in the input function to better prepare it for | |||
| 10 | // SelectionDAG-based code generation. This works around limitations in it's | |||
| 11 | // basic-block-at-a-time approach. It should eventually be removed. | |||
| 12 | // | |||
| 13 | //===----------------------------------------------------------------------===// | |||
| 14 | ||||
| 15 | #include "llvm/ADT/APInt.h" | |||
| 16 | #include "llvm/ADT/ArrayRef.h" | |||
| 17 | #include "llvm/ADT/DenseMap.h" | |||
| 18 | #include "llvm/ADT/MapVector.h" | |||
| 19 | #include "llvm/ADT/PointerIntPair.h" | |||
| 20 | #include "llvm/ADT/STLExtras.h" | |||
| 21 | #include "llvm/ADT/SmallPtrSet.h" | |||
| 22 | #include "llvm/ADT/SmallVector.h" | |||
| 23 | #include "llvm/ADT/Statistic.h" | |||
| 24 | #include "llvm/Analysis/BlockFrequencyInfo.h" | |||
| 25 | #include "llvm/Analysis/BranchProbabilityInfo.h" | |||
| 26 | #include "llvm/Analysis/ConstantFolding.h" | |||
| 27 | #include "llvm/Analysis/InstructionSimplify.h" | |||
| 28 | #include "llvm/Analysis/LoopInfo.h" | |||
| 29 | #include "llvm/Analysis/MemoryBuiltins.h" | |||
| 30 | #include "llvm/Analysis/ProfileSummaryInfo.h" | |||
| 31 | #include "llvm/Analysis/TargetLibraryInfo.h" | |||
| 32 | #include "llvm/Analysis/TargetTransformInfo.h" | |||
| 33 | #include "llvm/Analysis/ValueTracking.h" | |||
| 34 | #include "llvm/Analysis/VectorUtils.h" | |||
| 35 | #include "llvm/CodeGen/Analysis.h" | |||
| 36 | #include "llvm/CodeGen/ISDOpcodes.h" | |||
| 37 | #include "llvm/CodeGen/SelectionDAGNodes.h" | |||
| 38 | #include "llvm/CodeGen/TargetLowering.h" | |||
| 39 | #include "llvm/CodeGen/TargetPassConfig.h" | |||
| 40 | #include "llvm/CodeGen/TargetSubtargetInfo.h" | |||
| 41 | #include "llvm/CodeGen/ValueTypes.h" | |||
| 42 | #include "llvm/Config/llvm-config.h" | |||
| 43 | #include "llvm/IR/Argument.h" | |||
| 44 | #include "llvm/IR/Attributes.h" | |||
| 45 | #include "llvm/IR/BasicBlock.h" | |||
| 46 | #include "llvm/IR/Constant.h" | |||
| 47 | #include "llvm/IR/Constants.h" | |||
| 48 | #include "llvm/IR/DataLayout.h" | |||
| 49 | #include "llvm/IR/DebugInfo.h" | |||
| 50 | #include "llvm/IR/DerivedTypes.h" | |||
| 51 | #include "llvm/IR/Dominators.h" | |||
| 52 | #include "llvm/IR/Function.h" | |||
| 53 | #include "llvm/IR/GetElementPtrTypeIterator.h" | |||
| 54 | #include "llvm/IR/GlobalValue.h" | |||
| 55 | #include "llvm/IR/GlobalVariable.h" | |||
| 56 | #include "llvm/IR/IRBuilder.h" | |||
| 57 | #include "llvm/IR/InlineAsm.h" | |||
| 58 | #include "llvm/IR/InstrTypes.h" | |||
| 59 | #include "llvm/IR/Instruction.h" | |||
| 60 | #include "llvm/IR/Instructions.h" | |||
| 61 | #include "llvm/IR/IntrinsicInst.h" | |||
| 62 | #include "llvm/IR/Intrinsics.h" | |||
| 63 | #include "llvm/IR/IntrinsicsAArch64.h" | |||
| 64 | #include "llvm/IR/LLVMContext.h" | |||
| 65 | #include "llvm/IR/MDBuilder.h" | |||
| 66 | #include "llvm/IR/Module.h" | |||
| 67 | #include "llvm/IR/Operator.h" | |||
| 68 | #include "llvm/IR/PatternMatch.h" | |||
| 69 | #include "llvm/IR/Statepoint.h" | |||
| 70 | #include "llvm/IR/Type.h" | |||
| 71 | #include "llvm/IR/Use.h" | |||
| 72 | #include "llvm/IR/User.h" | |||
| 73 | #include "llvm/IR/Value.h" | |||
| 74 | #include "llvm/IR/ValueHandle.h" | |||
| 75 | #include "llvm/IR/ValueMap.h" | |||
| 76 | #include "llvm/InitializePasses.h" | |||
| 77 | #include "llvm/Pass.h" | |||
| 78 | #include "llvm/Support/BlockFrequency.h" | |||
| 79 | #include "llvm/Support/BranchProbability.h" | |||
| 80 | #include "llvm/Support/Casting.h" | |||
| 81 | #include "llvm/Support/CommandLine.h" | |||
| 82 | #include "llvm/Support/Compiler.h" | |||
| 83 | #include "llvm/Support/Debug.h" | |||
| 84 | #include "llvm/Support/ErrorHandling.h" | |||
| 85 | #include "llvm/Support/MachineValueType.h" | |||
| 86 | #include "llvm/Support/MathExtras.h" | |||
| 87 | #include "llvm/Support/raw_ostream.h" | |||
| 88 | #include "llvm/Target/TargetMachine.h" | |||
| 89 | #include "llvm/Target/TargetOptions.h" | |||
| 90 | #include "llvm/Transforms/Utils/BasicBlockUtils.h" | |||
| 91 | #include "llvm/Transforms/Utils/BypassSlowDivision.h" | |||
| 92 | #include "llvm/Transforms/Utils/Local.h" | |||
| 93 | #include "llvm/Transforms/Utils/SimplifyLibCalls.h" | |||
| 94 | #include "llvm/Transforms/Utils/SizeOpts.h" | |||
| 95 | #include <algorithm> | |||
| 96 | #include <cassert> | |||
| 97 | #include <cstdint> | |||
| 98 | #include <iterator> | |||
| 99 | #include <limits> | |||
| 100 | #include <memory> | |||
| 101 | #include <utility> | |||
| 102 | #include <vector> | |||
| 103 | ||||
| 104 | using namespace llvm; | |||
| 105 | using namespace llvm::PatternMatch; | |||
| 106 | ||||
| 107 | #define DEBUG_TYPE"codegenprepare" "codegenprepare" | |||
| 108 | ||||
| 109 | STATISTIC(NumBlocksElim, "Number of blocks eliminated")static llvm::Statistic NumBlocksElim = {"codegenprepare", "NumBlocksElim" , "Number of blocks eliminated"}; | |||
| 110 | STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated")static llvm::Statistic NumPHIsElim = {"codegenprepare", "NumPHIsElim" , "Number of trivial PHIs eliminated"}; | |||
| 111 | STATISTIC(NumGEPsElim, "Number of GEPs converted to casts")static llvm::Statistic NumGEPsElim = {"codegenprepare", "NumGEPsElim" , "Number of GEPs converted to casts"}; | |||
| 112 | STATISTIC(NumCmpUses, "Number of uses of Cmp expressions replaced with uses of "static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses" , "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps" } | |||
| 113 | "sunken Cmps")static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses" , "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps" }; | |||
| 114 | STATISTIC(NumCastUses, "Number of uses of Cast expressions replaced with uses "static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses" , "Number of uses of Cast expressions replaced with uses " "of sunken Casts" } | |||
| 115 | "of sunken Casts")static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses" , "Number of uses of Cast expressions replaced with uses " "of sunken Casts" }; | |||
| 116 | STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts" , "Number of memory instructions whose address " "computations were sunk" } | |||
| 117 | "computations were sunk")static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts" , "Number of memory instructions whose address " "computations were sunk" }; | |||
| 118 | STATISTIC(NumMemoryInstsPhiCreated,static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare" , "NumMemoryInstsPhiCreated", "Number of phis created when address " "computations were sunk to memory instructions"} | |||
| 119 | "Number of phis created when address "static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare" , "NumMemoryInstsPhiCreated", "Number of phis created when address " "computations were sunk to memory instructions"} | |||
| 120 | "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare" , "NumMemoryInstsPhiCreated", "Number of phis created when address " "computations were sunk to memory instructions"}; | |||
| 121 | STATISTIC(NumMemoryInstsSelectCreated,static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare" , "NumMemoryInstsSelectCreated", "Number of select created when address " "computations were sunk to memory instructions"} | |||
| 122 | "Number of select created when address "static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare" , "NumMemoryInstsSelectCreated", "Number of select created when address " "computations were sunk to memory instructions"} | |||
| 123 | "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare" , "NumMemoryInstsSelectCreated", "Number of select created when address " "computations were sunk to memory instructions"}; | |||
| 124 | STATISTIC(NumExtsMoved, "Number of [s|z]ext instructions combined with loads")static llvm::Statistic NumExtsMoved = {"codegenprepare", "NumExtsMoved" , "Number of [s|z]ext instructions combined with loads"}; | |||
| 125 | STATISTIC(NumExtUses, "Number of uses of [s|z]ext instructions optimized")static llvm::Statistic NumExtUses = {"codegenprepare", "NumExtUses" , "Number of uses of [s|z]ext instructions optimized"}; | |||
| 126 | STATISTIC(NumAndsAdded,static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded" , "Number of and mask instructions added to form ext loads"} | |||
| 127 | "Number of and mask instructions added to form ext loads")static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded" , "Number of and mask instructions added to form ext loads"}; | |||
| 128 | STATISTIC(NumAndUses, "Number of uses of and mask instructions optimized")static llvm::Statistic NumAndUses = {"codegenprepare", "NumAndUses" , "Number of uses of and mask instructions optimized"}; | |||
| 129 | STATISTIC(NumRetsDup, "Number of return instructions duplicated")static llvm::Statistic NumRetsDup = {"codegenprepare", "NumRetsDup" , "Number of return instructions duplicated"}; | |||
| 130 | STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved")static llvm::Statistic NumDbgValueMoved = {"codegenprepare", "NumDbgValueMoved" , "Number of debug value instructions moved"}; | |||
| 131 | STATISTIC(NumSelectsExpanded, "Number of selects turned into branches")static llvm::Statistic NumSelectsExpanded = {"codegenprepare" , "NumSelectsExpanded", "Number of selects turned into branches" }; | |||
| 132 | STATISTIC(NumStoreExtractExposed, "Number of store(extractelement) exposed")static llvm::Statistic NumStoreExtractExposed = {"codegenprepare" , "NumStoreExtractExposed", "Number of store(extractelement) exposed" }; | |||
| 133 | ||||
| 134 | static cl::opt<bool> DisableBranchOpts( | |||
| 135 | "disable-cgp-branch-opts", cl::Hidden, cl::init(false), | |||
| 136 | cl::desc("Disable branch optimizations in CodeGenPrepare")); | |||
| 137 | ||||
| 138 | static cl::opt<bool> | |||
| 139 | DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false), | |||
| 140 | cl::desc("Disable GC optimizations in CodeGenPrepare")); | |||
| 141 | ||||
| 142 | static cl::opt<bool> DisableSelectToBranch( | |||
| 143 | "disable-cgp-select2branch", cl::Hidden, cl::init(false), | |||
| 144 | cl::desc("Disable select to branch conversion.")); | |||
| 145 | ||||
| 146 | static cl::opt<bool> AddrSinkUsingGEPs( | |||
| 147 | "addr-sink-using-gep", cl::Hidden, cl::init(true), | |||
| 148 | cl::desc("Address sinking in CGP using GEPs.")); | |||
| 149 | ||||
| 150 | static cl::opt<bool> EnableAndCmpSinking( | |||
| 151 | "enable-andcmp-sinking", cl::Hidden, cl::init(true), | |||
| 152 | cl::desc("Enable sinkinig and/cmp into branches.")); | |||
| 153 | ||||
| 154 | static cl::opt<bool> DisableStoreExtract( | |||
| 155 | "disable-cgp-store-extract", cl::Hidden, cl::init(false), | |||
| 156 | cl::desc("Disable store(extract) optimizations in CodeGenPrepare")); | |||
| 157 | ||||
| 158 | static cl::opt<bool> StressStoreExtract( | |||
| 159 | "stress-cgp-store-extract", cl::Hidden, cl::init(false), | |||
| 160 | cl::desc("Stress test store(extract) optimizations in CodeGenPrepare")); | |||
| 161 | ||||
| 162 | static cl::opt<bool> DisableExtLdPromotion( | |||
| 163 | "disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false), | |||
| 164 | cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in " | |||
| 165 | "CodeGenPrepare")); | |||
| 166 | ||||
| 167 | static cl::opt<bool> StressExtLdPromotion( | |||
| 168 | "stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false), | |||
| 169 | cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) " | |||
| 170 | "optimization in CodeGenPrepare")); | |||
| 171 | ||||
| 172 | static cl::opt<bool> DisablePreheaderProtect( | |||
| 173 | "disable-preheader-prot", cl::Hidden, cl::init(false), | |||
| 174 | cl::desc("Disable protection against removing loop preheaders")); | |||
| 175 | ||||
| 176 | static cl::opt<bool> ProfileGuidedSectionPrefix( | |||
| 177 | "profile-guided-section-prefix", cl::Hidden, cl::init(true), cl::ZeroOrMore, | |||
| 178 | cl::desc("Use profile info to add section prefix for hot/cold functions")); | |||
| 179 | ||||
| 180 | static cl::opt<bool> ProfileUnknownInSpecialSection( | |||
| 181 | "profile-unknown-in-special-section", cl::Hidden, cl::init(false), | |||
| 182 | cl::ZeroOrMore, | |||
| 183 | cl::desc("In profiling mode like sampleFDO, if a function doesn't have " | |||
| 184 | "profile, we cannot tell the function is cold for sure because " | |||
| 185 | "it may be a function newly added without ever being sampled. " | |||
| 186 | "With the flag enabled, compiler can put such profile unknown " | |||
| 187 | "functions into a special section, so runtime system can choose " | |||
| 188 | "to handle it in a different way than .text section, to save " | |||
| 189 | "RAM for example. ")); | |||
| 190 | ||||
| 191 | static cl::opt<unsigned> FreqRatioToSkipMerge( | |||
| 192 | "cgp-freq-ratio-to-skip-merge", cl::Hidden, cl::init(2), | |||
| 193 | cl::desc("Skip merging empty blocks if (frequency of empty block) / " | |||
| 194 | "(frequency of destination block) is greater than this ratio")); | |||
| 195 | ||||
| 196 | static cl::opt<bool> ForceSplitStore( | |||
| 197 | "force-split-store", cl::Hidden, cl::init(false), | |||
| 198 | cl::desc("Force store splitting no matter what the target query says.")); | |||
| 199 | ||||
| 200 | static cl::opt<bool> | |||
| 201 | EnableTypePromotionMerge("cgp-type-promotion-merge", cl::Hidden, | |||
| 202 | cl::desc("Enable merging of redundant sexts when one is dominating" | |||
| 203 | " the other."), cl::init(true)); | |||
| 204 | ||||
| 205 | static cl::opt<bool> DisableComplexAddrModes( | |||
| 206 | "disable-complex-addr-modes", cl::Hidden, cl::init(false), | |||
| 207 | cl::desc("Disables combining addressing modes with different parts " | |||
| 208 | "in optimizeMemoryInst.")); | |||
| 209 | ||||
| 210 | static cl::opt<bool> | |||
| 211 | AddrSinkNewPhis("addr-sink-new-phis", cl::Hidden, cl::init(false), | |||
| 212 | cl::desc("Allow creation of Phis in Address sinking.")); | |||
| 213 | ||||
| 214 | static cl::opt<bool> | |||
| 215 | AddrSinkNewSelects("addr-sink-new-select", cl::Hidden, cl::init(true), | |||
| 216 | cl::desc("Allow creation of selects in Address sinking.")); | |||
| 217 | ||||
| 218 | static cl::opt<bool> AddrSinkCombineBaseReg( | |||
| 219 | "addr-sink-combine-base-reg", cl::Hidden, cl::init(true), | |||
| 220 | cl::desc("Allow combining of BaseReg field in Address sinking.")); | |||
| 221 | ||||
| 222 | static cl::opt<bool> AddrSinkCombineBaseGV( | |||
| 223 | "addr-sink-combine-base-gv", cl::Hidden, cl::init(true), | |||
| 224 | cl::desc("Allow combining of BaseGV field in Address sinking.")); | |||
| 225 | ||||
| 226 | static cl::opt<bool> AddrSinkCombineBaseOffs( | |||
| 227 | "addr-sink-combine-base-offs", cl::Hidden, cl::init(true), | |||
| 228 | cl::desc("Allow combining of BaseOffs field in Address sinking.")); | |||
| 229 | ||||
| 230 | static cl::opt<bool> AddrSinkCombineScaledReg( | |||
| 231 | "addr-sink-combine-scaled-reg", cl::Hidden, cl::init(true), | |||
| 232 | cl::desc("Allow combining of ScaledReg field in Address sinking.")); | |||
| 233 | ||||
| 234 | static cl::opt<bool> | |||
| 235 | EnableGEPOffsetSplit("cgp-split-large-offset-gep", cl::Hidden, | |||
| 236 | cl::init(true), | |||
| 237 | cl::desc("Enable splitting large offset of GEP.")); | |||
| 238 | ||||
| 239 | static cl::opt<bool> EnableICMP_EQToICMP_ST( | |||
| 240 | "cgp-icmp-eq2icmp-st", cl::Hidden, cl::init(false), | |||
| 241 | cl::desc("Enable ICMP_EQ to ICMP_S(L|G)T conversion.")); | |||
| 242 | ||||
| 243 | static cl::opt<bool> | |||
| 244 | VerifyBFIUpdates("cgp-verify-bfi-updates", cl::Hidden, cl::init(false), | |||
| 245 | cl::desc("Enable BFI update verification for " | |||
| 246 | "CodeGenPrepare.")); | |||
| 247 | ||||
| 248 | static cl::opt<bool> OptimizePhiTypes( | |||
| 249 | "cgp-optimize-phi-types", cl::Hidden, cl::init(false), | |||
| 250 | cl::desc("Enable converting phi types in CodeGenPrepare")); | |||
| 251 | ||||
| 252 | namespace { | |||
| 253 | ||||
| 254 | enum ExtType { | |||
| 255 | ZeroExtension, // Zero extension has been seen. | |||
| 256 | SignExtension, // Sign extension has been seen. | |||
| 257 | BothExtension // This extension type is used if we saw sext after | |||
| 258 | // ZeroExtension had been set, or if we saw zext after | |||
| 259 | // SignExtension had been set. It makes the type | |||
| 260 | // information of a promoted instruction invalid. | |||
| 261 | }; | |||
| 262 | ||||
| 263 | using SetOfInstrs = SmallPtrSet<Instruction *, 16>; | |||
| 264 | using TypeIsSExt = PointerIntPair<Type *, 2, ExtType>; | |||
| 265 | using InstrToOrigTy = DenseMap<Instruction *, TypeIsSExt>; | |||
| 266 | using SExts = SmallVector<Instruction *, 16>; | |||
| 267 | using ValueToSExts = DenseMap<Value *, SExts>; | |||
| 268 | ||||
| 269 | class TypePromotionTransaction; | |||
| 270 | ||||
| 271 | class CodeGenPrepare : public FunctionPass { | |||
| 272 | const TargetMachine *TM = nullptr; | |||
| 273 | const TargetSubtargetInfo *SubtargetInfo; | |||
| 274 | const TargetLowering *TLI = nullptr; | |||
| 275 | const TargetRegisterInfo *TRI; | |||
| 276 | const TargetTransformInfo *TTI = nullptr; | |||
| 277 | const TargetLibraryInfo *TLInfo; | |||
| 278 | const LoopInfo *LI; | |||
| 279 | std::unique_ptr<BlockFrequencyInfo> BFI; | |||
| 280 | std::unique_ptr<BranchProbabilityInfo> BPI; | |||
| 281 | ProfileSummaryInfo *PSI; | |||
| 282 | ||||
| 283 | /// As we scan instructions optimizing them, this is the next instruction | |||
| 284 | /// to optimize. Transforms that can invalidate this should update it. | |||
| 285 | BasicBlock::iterator CurInstIterator; | |||
| 286 | ||||
| 287 | /// Keeps track of non-local addresses that have been sunk into a block. | |||
| 288 | /// This allows us to avoid inserting duplicate code for blocks with | |||
| 289 | /// multiple load/stores of the same address. The usage of WeakTrackingVH | |||
| 290 | /// enables SunkAddrs to be treated as a cache whose entries can be | |||
| 291 | /// invalidated if a sunken address computation has been erased. | |||
| 292 | ValueMap<Value*, WeakTrackingVH> SunkAddrs; | |||
| 293 | ||||
| 294 | /// Keeps track of all instructions inserted for the current function. | |||
| 295 | SetOfInstrs InsertedInsts; | |||
| 296 | ||||
| 297 | /// Keeps track of the type of the related instruction before their | |||
| 298 | /// promotion for the current function. | |||
| 299 | InstrToOrigTy PromotedInsts; | |||
| 300 | ||||
| 301 | /// Keep track of instructions removed during promotion. | |||
| 302 | SetOfInstrs RemovedInsts; | |||
| 303 | ||||
| 304 | /// Keep track of sext chains based on their initial value. | |||
| 305 | DenseMap<Value *, Instruction *> SeenChainsForSExt; | |||
| 306 | ||||
| 307 | /// Keep track of GEPs accessing the same data structures such as structs or | |||
| 308 | /// arrays that are candidates to be split later because of their large | |||
| 309 | /// size. | |||
| 310 | MapVector< | |||
| 311 | AssertingVH<Value>, | |||
| 312 | SmallVector<std::pair<AssertingVH<GetElementPtrInst>, int64_t>, 32>> | |||
| 313 | LargeOffsetGEPMap; | |||
| 314 | ||||
| 315 | /// Keep track of new GEP base after splitting the GEPs having large offset. | |||
| 316 | SmallSet<AssertingVH<Value>, 2> NewGEPBases; | |||
| 317 | ||||
| 318 | /// Map serial numbers to Large offset GEPs. | |||
| 319 | DenseMap<AssertingVH<GetElementPtrInst>, int> LargeOffsetGEPID; | |||
| 320 | ||||
| 321 | /// Keep track of SExt promoted. | |||
| 322 | ValueToSExts ValToSExtendedUses; | |||
| 323 | ||||
| 324 | /// True if the function has the OptSize attribute. | |||
| 325 | bool OptSize; | |||
| 326 | ||||
| 327 | /// DataLayout for the Function being processed. | |||
| 328 | const DataLayout *DL = nullptr; | |||
| 329 | ||||
| 330 | /// Building the dominator tree can be expensive, so we only build it | |||
| 331 | /// lazily and update it when required. | |||
| 332 | std::unique_ptr<DominatorTree> DT; | |||
| 333 | ||||
| 334 | public: | |||
| 335 | static char ID; // Pass identification, replacement for typeid | |||
| 336 | ||||
| 337 | CodeGenPrepare() : FunctionPass(ID) { | |||
| 338 | initializeCodeGenPreparePass(*PassRegistry::getPassRegistry()); | |||
| 339 | } | |||
| 340 | ||||
| 341 | bool runOnFunction(Function &F) override; | |||
| 342 | ||||
| 343 | StringRef getPassName() const override { return "CodeGen Prepare"; } | |||
| 344 | ||||
| 345 | void getAnalysisUsage(AnalysisUsage &AU) const override { | |||
| 346 | // FIXME: When we can selectively preserve passes, preserve the domtree. | |||
| 347 | AU.addRequired<ProfileSummaryInfoWrapperPass>(); | |||
| 348 | AU.addRequired<TargetLibraryInfoWrapperPass>(); | |||
| 349 | AU.addRequired<TargetPassConfig>(); | |||
| 350 | AU.addRequired<TargetTransformInfoWrapperPass>(); | |||
| 351 | AU.addRequired<LoopInfoWrapperPass>(); | |||
| 352 | } | |||
| 353 | ||||
| 354 | private: | |||
| 355 | template <typename F> | |||
| 356 | void resetIteratorIfInvalidatedWhileCalling(BasicBlock *BB, F f) { | |||
| 357 | // Substituting can cause recursive simplifications, which can invalidate | |||
| 358 | // our iterator. Use a WeakTrackingVH to hold onto it in case this | |||
| 359 | // happens. | |||
| 360 | Value *CurValue = &*CurInstIterator; | |||
| 361 | WeakTrackingVH IterHandle(CurValue); | |||
| 362 | ||||
| 363 | f(); | |||
| 364 | ||||
| 365 | // If the iterator instruction was recursively deleted, start over at the | |||
| 366 | // start of the block. | |||
| 367 | if (IterHandle != CurValue) { | |||
| 368 | CurInstIterator = BB->begin(); | |||
| 369 | SunkAddrs.clear(); | |||
| 370 | } | |||
| 371 | } | |||
| 372 | ||||
| 373 | // Get the DominatorTree, building if necessary. | |||
| 374 | DominatorTree &getDT(Function &F) { | |||
| 375 | if (!DT) | |||
| 376 | DT = std::make_unique<DominatorTree>(F); | |||
| 377 | return *DT; | |||
| 378 | } | |||
| 379 | ||||
| 380 | void removeAllAssertingVHReferences(Value *V); | |||
| 381 | bool eliminateAssumptions(Function &F); | |||
| 382 | bool eliminateFallThrough(Function &F); | |||
| 383 | bool eliminateMostlyEmptyBlocks(Function &F); | |||
| 384 | BasicBlock *findDestBlockOfMergeableEmptyBlock(BasicBlock *BB); | |||
| 385 | bool canMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const; | |||
| 386 | void eliminateMostlyEmptyBlock(BasicBlock *BB); | |||
| 387 | bool isMergingEmptyBlockProfitable(BasicBlock *BB, BasicBlock *DestBB, | |||
| 388 | bool isPreheader); | |||
| 389 | bool makeBitReverse(Instruction &I); | |||
| 390 | bool optimizeBlock(BasicBlock &BB, bool &ModifiedDT); | |||
| 391 | bool optimizeInst(Instruction *I, bool &ModifiedDT); | |||
| 392 | bool optimizeMemoryInst(Instruction *MemoryInst, Value *Addr, | |||
| 393 | Type *AccessTy, unsigned AddrSpace); | |||
| 394 | bool optimizeGatherScatterInst(Instruction *MemoryInst, Value *Ptr); | |||
| 395 | bool optimizeInlineAsmInst(CallInst *CS); | |||
| 396 | bool optimizeCallInst(CallInst *CI, bool &ModifiedDT); | |||
| 397 | bool optimizeExt(Instruction *&I); | |||
| 398 | bool optimizeExtUses(Instruction *I); | |||
| 399 | bool optimizeLoadExt(LoadInst *Load); | |||
| 400 | bool optimizeShiftInst(BinaryOperator *BO); | |||
| 401 | bool optimizeFunnelShift(IntrinsicInst *Fsh); | |||
| 402 | bool optimizeSelectInst(SelectInst *SI); | |||
| 403 | bool optimizeShuffleVectorInst(ShuffleVectorInst *SVI); | |||
| 404 | bool optimizeSwitchInst(SwitchInst *SI); | |||
| 405 | bool optimizeExtractElementInst(Instruction *Inst); | |||
| 406 | bool dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT); | |||
| 407 | bool fixupDbgValue(Instruction *I); | |||
| 408 | bool placeDbgValues(Function &F); | |||
| 409 | bool placePseudoProbes(Function &F); | |||
| 410 | bool canFormExtLd(const SmallVectorImpl<Instruction *> &MovedExts, | |||
| 411 | LoadInst *&LI, Instruction *&Inst, bool HasPromoted); | |||
| 412 | bool tryToPromoteExts(TypePromotionTransaction &TPT, | |||
| 413 | const SmallVectorImpl<Instruction *> &Exts, | |||
| 414 | SmallVectorImpl<Instruction *> &ProfitablyMovedExts, | |||
| 415 | unsigned CreatedInstsCost = 0); | |||
| 416 | bool mergeSExts(Function &F); | |||
| 417 | bool splitLargeGEPOffsets(); | |||
| 418 | bool optimizePhiType(PHINode *Inst, SmallPtrSetImpl<PHINode *> &Visited, | |||
| 419 | SmallPtrSetImpl<Instruction *> &DeletedInstrs); | |||
| 420 | bool optimizePhiTypes(Function &F); | |||
| 421 | bool performAddressTypePromotion( | |||
| 422 | Instruction *&Inst, | |||
| 423 | bool AllowPromotionWithoutCommonHeader, | |||
| 424 | bool HasPromoted, TypePromotionTransaction &TPT, | |||
| 425 | SmallVectorImpl<Instruction *> &SpeculativelyMovedExts); | |||
| 426 | bool splitBranchCondition(Function &F, bool &ModifiedDT); | |||
| 427 | bool simplifyOffsetableRelocate(GCStatepointInst &I); | |||
| 428 | ||||
| 429 | bool tryToSinkFreeOperands(Instruction *I); | |||
| 430 | bool replaceMathCmpWithIntrinsic(BinaryOperator *BO, Value *Arg0, | |||
| 431 | Value *Arg1, CmpInst *Cmp, | |||
| 432 | Intrinsic::ID IID); | |||
| 433 | bool optimizeCmp(CmpInst *Cmp, bool &ModifiedDT); | |||
| 434 | bool combineToUSubWithOverflow(CmpInst *Cmp, bool &ModifiedDT); | |||
| 435 | bool combineToUAddWithOverflow(CmpInst *Cmp, bool &ModifiedDT); | |||
| 436 | void verifyBFIUpdates(Function &F); | |||
| 437 | }; | |||
| 438 | ||||
| 439 | } // end anonymous namespace | |||
| 440 | ||||
| 441 | char CodeGenPrepare::ID = 0; | |||
| 442 | ||||
| 443 | INITIALIZE_PASS_BEGIN(CodeGenPrepare, DEBUG_TYPE,static void *initializeCodeGenPreparePassOnce(PassRegistry & Registry) { | |||
| 444 | "Optimize for code generation", false, false)static void *initializeCodeGenPreparePassOnce(PassRegistry & Registry) { | |||
| 445 | INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry); | |||
| 446 | INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry); | |||
| 447 | INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry); | |||
| 448 | INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)initializeTargetPassConfigPass(Registry); | |||
| 449 | INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry); | |||
| 450 | INITIALIZE_PASS_END(CodeGenPrepare, DEBUG_TYPE,PassInfo *PI = new PassInfo( "Optimize for code generation", "codegenprepare" , &CodeGenPrepare::ID, PassInfo::NormalCtor_t(callDefaultCtor <CodeGenPrepare>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeCodeGenPreparePassFlag ; void llvm::initializeCodeGenPreparePass(PassRegistry &Registry ) { llvm::call_once(InitializeCodeGenPreparePassFlag, initializeCodeGenPreparePassOnce , std::ref(Registry)); } | |||
| 451 | "Optimize for code generation", false, false)PassInfo *PI = new PassInfo( "Optimize for code generation", "codegenprepare" , &CodeGenPrepare::ID, PassInfo::NormalCtor_t(callDefaultCtor <CodeGenPrepare>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeCodeGenPreparePassFlag ; void llvm::initializeCodeGenPreparePass(PassRegistry &Registry ) { llvm::call_once(InitializeCodeGenPreparePassFlag, initializeCodeGenPreparePassOnce , std::ref(Registry)); } | |||
| 452 | ||||
| 453 | FunctionPass *llvm::createCodeGenPreparePass() { return new CodeGenPrepare(); } | |||
| 454 | ||||
| 455 | bool CodeGenPrepare::runOnFunction(Function &F) { | |||
| 456 | if (skipFunction(F)) | |||
| 457 | return false; | |||
| 458 | ||||
| 459 | DL = &F.getParent()->getDataLayout(); | |||
| 460 | ||||
| 461 | bool EverMadeChange = false; | |||
| 462 | // Clear per function information. | |||
| 463 | InsertedInsts.clear(); | |||
| 464 | PromotedInsts.clear(); | |||
| 465 | ||||
| 466 | TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>(); | |||
| 467 | SubtargetInfo = TM->getSubtargetImpl(F); | |||
| 468 | TLI = SubtargetInfo->getTargetLowering(); | |||
| 469 | TRI = SubtargetInfo->getRegisterInfo(); | |||
| 470 | TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); | |||
| 471 | TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F); | |||
| 472 | LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo(); | |||
| 473 | BPI.reset(new BranchProbabilityInfo(F, *LI)); | |||
| 474 | BFI.reset(new BlockFrequencyInfo(F, *BPI, *LI)); | |||
| 475 | PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI(); | |||
| 476 | OptSize = F.hasOptSize(); | |||
| 477 | if (ProfileGuidedSectionPrefix) { | |||
| 478 | // The hot attribute overwrites profile count based hotness while profile | |||
| 479 | // counts based hotness overwrite the cold attribute. | |||
| 480 | // This is a conservative behabvior. | |||
| 481 | if (F.hasFnAttribute(Attribute::Hot) || | |||
| 482 | PSI->isFunctionHotInCallGraph(&F, *BFI)) | |||
| 483 | F.setSectionPrefix("hot"); | |||
| 484 | // If PSI shows this function is not hot, we will placed the function | |||
| 485 | // into unlikely section if (1) PSI shows this is a cold function, or | |||
| 486 | // (2) the function has a attribute of cold. | |||
| 487 | else if (PSI->isFunctionColdInCallGraph(&F, *BFI) || | |||
| 488 | F.hasFnAttribute(Attribute::Cold)) | |||
| 489 | F.setSectionPrefix("unlikely"); | |||
| 490 | else if (ProfileUnknownInSpecialSection && PSI->hasPartialSampleProfile() && | |||
| 491 | PSI->isFunctionHotnessUnknown(F)) | |||
| 492 | F.setSectionPrefix("unknown"); | |||
| 493 | } | |||
| 494 | ||||
| 495 | /// This optimization identifies DIV instructions that can be | |||
| 496 | /// profitably bypassed and carried out with a shorter, faster divide. | |||
| 497 | if (!OptSize && !PSI->hasHugeWorkingSetSize() && TLI->isSlowDivBypassed()) { | |||
| 498 | const DenseMap<unsigned int, unsigned int> &BypassWidths = | |||
| 499 | TLI->getBypassSlowDivWidths(); | |||
| 500 | BasicBlock* BB = &*F.begin(); | |||
| 501 | while (BB != nullptr) { | |||
| 502 | // bypassSlowDivision may create new BBs, but we don't want to reapply the | |||
| 503 | // optimization to those blocks. | |||
| 504 | BasicBlock* Next = BB->getNextNode(); | |||
| 505 | // F.hasOptSize is already checked in the outer if statement. | |||
| 506 | if (!llvm::shouldOptimizeForSize(BB, PSI, BFI.get())) | |||
| 507 | EverMadeChange |= bypassSlowDivision(BB, BypassWidths); | |||
| 508 | BB = Next; | |||
| 509 | } | |||
| 510 | } | |||
| 511 | ||||
| 512 | // Get rid of @llvm.assume builtins before attempting to eliminate empty | |||
| 513 | // blocks, since there might be blocks that only contain @llvm.assume calls | |||
| 514 | // (plus arguments that we can get rid of). | |||
| 515 | EverMadeChange |= eliminateAssumptions(F); | |||
| 516 | ||||
| 517 | // Eliminate blocks that contain only PHI nodes and an | |||
| 518 | // unconditional branch. | |||
| 519 | EverMadeChange |= eliminateMostlyEmptyBlocks(F); | |||
| 520 | ||||
| 521 | bool ModifiedDT = false; | |||
| 522 | if (!DisableBranchOpts) | |||
| 523 | EverMadeChange |= splitBranchCondition(F, ModifiedDT); | |||
| 524 | ||||
| 525 | // Split some critical edges where one of the sources is an indirect branch, | |||
| 526 | // to help generate sane code for PHIs involving such edges. | |||
| 527 | EverMadeChange |= SplitIndirectBrCriticalEdges(F); | |||
| 528 | ||||
| 529 | bool MadeChange = true; | |||
| 530 | while (MadeChange) { | |||
| 531 | MadeChange = false; | |||
| 532 | DT.reset(); | |||
| 533 | for (Function::iterator I = F.begin(); I != F.end(); ) { | |||
| 534 | BasicBlock *BB = &*I++; | |||
| 535 | bool ModifiedDTOnIteration = false; | |||
| 536 | MadeChange |= optimizeBlock(*BB, ModifiedDTOnIteration); | |||
| 537 | ||||
| 538 | // Restart BB iteration if the dominator tree of the Function was changed | |||
| 539 | if (ModifiedDTOnIteration) | |||
| 540 | break; | |||
| 541 | } | |||
| 542 | if (EnableTypePromotionMerge && !ValToSExtendedUses.empty()) | |||
| 543 | MadeChange |= mergeSExts(F); | |||
| 544 | if (!LargeOffsetGEPMap.empty()) | |||
| 545 | MadeChange |= splitLargeGEPOffsets(); | |||
| 546 | MadeChange |= optimizePhiTypes(F); | |||
| 547 | ||||
| 548 | if (MadeChange) | |||
| 549 | eliminateFallThrough(F); | |||
| 550 | ||||
| 551 | // Really free removed instructions during promotion. | |||
| 552 | for (Instruction *I : RemovedInsts) | |||
| 553 | I->deleteValue(); | |||
| 554 | ||||
| 555 | EverMadeChange |= MadeChange; | |||
| 556 | SeenChainsForSExt.clear(); | |||
| 557 | ValToSExtendedUses.clear(); | |||
| 558 | RemovedInsts.clear(); | |||
| 559 | LargeOffsetGEPMap.clear(); | |||
| 560 | LargeOffsetGEPID.clear(); | |||
| 561 | } | |||
| 562 | ||||
| 563 | NewGEPBases.clear(); | |||
| 564 | SunkAddrs.clear(); | |||
| 565 | ||||
| 566 | if (!DisableBranchOpts) { | |||
| 567 | MadeChange = false; | |||
| 568 | // Use a set vector to get deterministic iteration order. The order the | |||
| 569 | // blocks are removed may affect whether or not PHI nodes in successors | |||
| 570 | // are removed. | |||
| 571 | SmallSetVector<BasicBlock*, 8> WorkList; | |||
| 572 | for (BasicBlock &BB : F) { | |||
| 573 | SmallVector<BasicBlock *, 2> Successors(successors(&BB)); | |||
| 574 | MadeChange |= ConstantFoldTerminator(&BB, true); | |||
| 575 | if (!MadeChange) continue; | |||
| 576 | ||||
| 577 | for (BasicBlock *Succ : Successors) | |||
| 578 | if (pred_empty(Succ)) | |||
| 579 | WorkList.insert(Succ); | |||
| 580 | } | |||
| 581 | ||||
| 582 | // Delete the dead blocks and any of their dead successors. | |||
| 583 | MadeChange |= !WorkList.empty(); | |||
| 584 | while (!WorkList.empty()) { | |||
| 585 | BasicBlock *BB = WorkList.pop_back_val(); | |||
| 586 | SmallVector<BasicBlock*, 2> Successors(successors(BB)); | |||
| 587 | ||||
| 588 | DeleteDeadBlock(BB); | |||
| 589 | ||||
| 590 | for (BasicBlock *Succ : Successors) | |||
| 591 | if (pred_empty(Succ)) | |||
| 592 | WorkList.insert(Succ); | |||
| 593 | } | |||
| 594 | ||||
| 595 | // Merge pairs of basic blocks with unconditional branches, connected by | |||
| 596 | // a single edge. | |||
| 597 | if (EverMadeChange || MadeChange) | |||
| 598 | MadeChange |= eliminateFallThrough(F); | |||
| 599 | ||||
| 600 | EverMadeChange |= MadeChange; | |||
| 601 | } | |||
| 602 | ||||
| 603 | if (!DisableGCOpts) { | |||
| 604 | SmallVector<GCStatepointInst *, 2> Statepoints; | |||
| 605 | for (BasicBlock &BB : F) | |||
| 606 | for (Instruction &I : BB) | |||
| 607 | if (auto *SP = dyn_cast<GCStatepointInst>(&I)) | |||
| 608 | Statepoints.push_back(SP); | |||
| 609 | for (auto &I : Statepoints) | |||
| 610 | EverMadeChange |= simplifyOffsetableRelocate(*I); | |||
| 611 | } | |||
| 612 | ||||
| 613 | // Do this last to clean up use-before-def scenarios introduced by other | |||
| 614 | // preparatory transforms. | |||
| 615 | EverMadeChange |= placeDbgValues(F); | |||
| 616 | EverMadeChange |= placePseudoProbes(F); | |||
| 617 | ||||
| 618 | #ifndef NDEBUG1 | |||
| 619 | if (VerifyBFIUpdates) | |||
| 620 | verifyBFIUpdates(F); | |||
| 621 | #endif | |||
| 622 | ||||
| 623 | return EverMadeChange; | |||
| 624 | } | |||
| 625 | ||||
| 626 | bool CodeGenPrepare::eliminateAssumptions(Function &F) { | |||
| 627 | bool MadeChange = false; | |||
| 628 | for (BasicBlock &BB : F) { | |||
| 629 | CurInstIterator = BB.begin(); | |||
| 630 | while (CurInstIterator != BB.end()) { | |||
| 631 | Instruction *I = &*(CurInstIterator++); | |||
| 632 | if (auto *Assume = dyn_cast<AssumeInst>(I)) { | |||
| 633 | MadeChange = true; | |||
| 634 | Value *Operand = Assume->getOperand(0); | |||
| 635 | Assume->eraseFromParent(); | |||
| 636 | ||||
| 637 | resetIteratorIfInvalidatedWhileCalling(&BB, [&]() { | |||
| 638 | RecursivelyDeleteTriviallyDeadInstructions(Operand, TLInfo, nullptr); | |||
| 639 | }); | |||
| 640 | } | |||
| 641 | } | |||
| 642 | } | |||
| 643 | return MadeChange; | |||
| 644 | } | |||
| 645 | ||||
| 646 | /// An instruction is about to be deleted, so remove all references to it in our | |||
| 647 | /// GEP-tracking data strcutures. | |||
| 648 | void CodeGenPrepare::removeAllAssertingVHReferences(Value *V) { | |||
| 649 | LargeOffsetGEPMap.erase(V); | |||
| 650 | NewGEPBases.erase(V); | |||
| 651 | ||||
| 652 | auto GEP = dyn_cast<GetElementPtrInst>(V); | |||
| 653 | if (!GEP) | |||
| 654 | return; | |||
| 655 | ||||
| 656 | LargeOffsetGEPID.erase(GEP); | |||
| 657 | ||||
| 658 | auto VecI = LargeOffsetGEPMap.find(GEP->getPointerOperand()); | |||
| 659 | if (VecI == LargeOffsetGEPMap.end()) | |||
| 660 | return; | |||
| 661 | ||||
| 662 | auto &GEPVector = VecI->second; | |||
| 663 | const auto &I = | |||
| 664 | llvm::find_if(GEPVector, [=](auto &Elt) { return Elt.first == GEP; }); | |||
| 665 | if (I == GEPVector.end()) | |||
| 666 | return; | |||
| 667 | ||||
| 668 | GEPVector.erase(I); | |||
| 669 | if (GEPVector.empty()) | |||
| 670 | LargeOffsetGEPMap.erase(VecI); | |||
| 671 | } | |||
| 672 | ||||
| 673 | // Verify BFI has been updated correctly by recomputing BFI and comparing them. | |||
| 674 | void LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__)) CodeGenPrepare::verifyBFIUpdates(Function &F) { | |||
| 675 | DominatorTree NewDT(F); | |||
| 676 | LoopInfo NewLI(NewDT); | |||
| 677 | BranchProbabilityInfo NewBPI(F, NewLI, TLInfo); | |||
| 678 | BlockFrequencyInfo NewBFI(F, NewBPI, NewLI); | |||
| 679 | NewBFI.verifyMatch(*BFI); | |||
| 680 | } | |||
| 681 | ||||
| 682 | /// Merge basic blocks which are connected by a single edge, where one of the | |||
| 683 | /// basic blocks has a single successor pointing to the other basic block, | |||
| 684 | /// which has a single predecessor. | |||
| 685 | bool CodeGenPrepare::eliminateFallThrough(Function &F) { | |||
| 686 | bool Changed = false; | |||
| 687 | // Scan all of the blocks in the function, except for the entry block. | |||
| 688 | // Use a temporary array to avoid iterator being invalidated when | |||
| 689 | // deleting blocks. | |||
| 690 | SmallVector<WeakTrackingVH, 16> Blocks; | |||
| 691 | for (auto &Block : llvm::drop_begin(F)) | |||
| 692 | Blocks.push_back(&Block); | |||
| 693 | ||||
| 694 | SmallSet<WeakTrackingVH, 16> Preds; | |||
| 695 | for (auto &Block : Blocks) { | |||
| 696 | auto *BB = cast_or_null<BasicBlock>(Block); | |||
| 697 | if (!BB) | |||
| 698 | continue; | |||
| 699 | // If the destination block has a single pred, then this is a trivial | |||
| 700 | // edge, just collapse it. | |||
| 701 | BasicBlock *SinglePred = BB->getSinglePredecessor(); | |||
| 702 | ||||
| 703 | // Don't merge if BB's address is taken. | |||
| 704 | if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue; | |||
| 705 | ||||
| 706 | BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator()); | |||
| 707 | if (Term && !Term->isConditional()) { | |||
| 708 | Changed = true; | |||
| 709 | LLVM_DEBUG(dbgs() << "To merge:\n" << *BB << "\n\n\n")do { } while (false); | |||
| 710 | ||||
| 711 | // Merge BB into SinglePred and delete it. | |||
| 712 | MergeBlockIntoPredecessor(BB); | |||
| 713 | Preds.insert(SinglePred); | |||
| 714 | } | |||
| 715 | } | |||
| 716 | ||||
| 717 | // (Repeatedly) merging blocks into their predecessors can create redundant | |||
| 718 | // debug intrinsics. | |||
| 719 | for (auto &Pred : Preds) | |||
| 720 | if (auto *BB = cast_or_null<BasicBlock>(Pred)) | |||
| 721 | RemoveRedundantDbgInstrs(BB); | |||
| 722 | ||||
| 723 | return Changed; | |||
| 724 | } | |||
| 725 | ||||
| 726 | /// Find a destination block from BB if BB is mergeable empty block. | |||
| 727 | BasicBlock *CodeGenPrepare::findDestBlockOfMergeableEmptyBlock(BasicBlock *BB) { | |||
| 728 | // If this block doesn't end with an uncond branch, ignore it. | |||
| 729 | BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator()); | |||
| 730 | if (!BI || !BI->isUnconditional()) | |||
| 731 | return nullptr; | |||
| 732 | ||||
| 733 | // If the instruction before the branch (skipping debug info) isn't a phi | |||
| 734 | // node, then other stuff is happening here. | |||
| 735 | BasicBlock::iterator BBI = BI->getIterator(); | |||
| 736 | if (BBI != BB->begin()) { | |||
| 737 | --BBI; | |||
| 738 | while (isa<DbgInfoIntrinsic>(BBI)) { | |||
| 739 | if (BBI == BB->begin()) | |||
| 740 | break; | |||
| 741 | --BBI; | |||
| 742 | } | |||
| 743 | if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI)) | |||
| 744 | return nullptr; | |||
| 745 | } | |||
| 746 | ||||
| 747 | // Do not break infinite loops. | |||
| 748 | BasicBlock *DestBB = BI->getSuccessor(0); | |||
| 749 | if (DestBB == BB) | |||
| 750 | return nullptr; | |||
| 751 | ||||
| 752 | if (!canMergeBlocks(BB, DestBB)) | |||
| 753 | DestBB = nullptr; | |||
| 754 | ||||
| 755 | return DestBB; | |||
| 756 | } | |||
| 757 | ||||
| 758 | /// Eliminate blocks that contain only PHI nodes, debug info directives, and an | |||
| 759 | /// unconditional branch. Passes before isel (e.g. LSR/loopsimplify) often split | |||
| 760 | /// edges in ways that are non-optimal for isel. Start by eliminating these | |||
| 761 | /// blocks so we can split them the way we want them. | |||
| 762 | bool CodeGenPrepare::eliminateMostlyEmptyBlocks(Function &F) { | |||
| 763 | SmallPtrSet<BasicBlock *, 16> Preheaders; | |||
| 764 | SmallVector<Loop *, 16> LoopList(LI->begin(), LI->end()); | |||
| 765 | while (!LoopList.empty()) { | |||
| 766 | Loop *L = LoopList.pop_back_val(); | |||
| 767 | llvm::append_range(LoopList, *L); | |||
| 768 | if (BasicBlock *Preheader = L->getLoopPreheader()) | |||
| 769 | Preheaders.insert(Preheader); | |||
| 770 | } | |||
| 771 | ||||
| 772 | bool MadeChange = false; | |||
| 773 | // Copy blocks into a temporary array to avoid iterator invalidation issues | |||
| 774 | // as we remove them. | |||
| 775 | // Note that this intentionally skips the entry block. | |||
| 776 | SmallVector<WeakTrackingVH, 16> Blocks; | |||
| 777 | for (auto &Block : llvm::drop_begin(F)) | |||
| 778 | Blocks.push_back(&Block); | |||
| 779 | ||||
| 780 | for (auto &Block : Blocks) { | |||
| 781 | BasicBlock *BB = cast_or_null<BasicBlock>(Block); | |||
| 782 | if (!BB) | |||
| 783 | continue; | |||
| 784 | BasicBlock *DestBB = findDestBlockOfMergeableEmptyBlock(BB); | |||
| 785 | if (!DestBB || | |||
| 786 | !isMergingEmptyBlockProfitable(BB, DestBB, Preheaders.count(BB))) | |||
| 787 | continue; | |||
| 788 | ||||
| 789 | eliminateMostlyEmptyBlock(BB); | |||
| 790 | MadeChange = true; | |||
| 791 | } | |||
| 792 | return MadeChange; | |||
| 793 | } | |||
| 794 | ||||
| 795 | bool CodeGenPrepare::isMergingEmptyBlockProfitable(BasicBlock *BB, | |||
| 796 | BasicBlock *DestBB, | |||
| 797 | bool isPreheader) { | |||
| 798 | // Do not delete loop preheaders if doing so would create a critical edge. | |||
| 799 | // Loop preheaders can be good locations to spill registers. If the | |||
| 800 | // preheader is deleted and we create a critical edge, registers may be | |||
| 801 | // spilled in the loop body instead. | |||
| 802 | if (!DisablePreheaderProtect && isPreheader && | |||
| 803 | !(BB->getSinglePredecessor() && | |||
| 804 | BB->getSinglePredecessor()->getSingleSuccessor())) | |||
| 805 | return false; | |||
| 806 | ||||
| 807 | // Skip merging if the block's successor is also a successor to any callbr | |||
| 808 | // that leads to this block. | |||
| 809 | // FIXME: Is this really needed? Is this a correctness issue? | |||
| 810 | for (BasicBlock *Pred : predecessors(BB)) { | |||
| 811 | if (auto *CBI = dyn_cast<CallBrInst>((Pred)->getTerminator())) | |||
| 812 | for (unsigned i = 0, e = CBI->getNumSuccessors(); i != e; ++i) | |||
| 813 | if (DestBB == CBI->getSuccessor(i)) | |||
| 814 | return false; | |||
| 815 | } | |||
| 816 | ||||
| 817 | // Try to skip merging if the unique predecessor of BB is terminated by a | |||
| 818 | // switch or indirect branch instruction, and BB is used as an incoming block | |||
| 819 | // of PHIs in DestBB. In such case, merging BB and DestBB would cause ISel to | |||
| 820 | // add COPY instructions in the predecessor of BB instead of BB (if it is not | |||
| 821 | // merged). Note that the critical edge created by merging such blocks wont be | |||
| 822 | // split in MachineSink because the jump table is not analyzable. By keeping | |||
| 823 | // such empty block (BB), ISel will place COPY instructions in BB, not in the | |||
| 824 | // predecessor of BB. | |||
| 825 | BasicBlock *Pred = BB->getUniquePredecessor(); | |||
| 826 | if (!Pred || | |||
| 827 | !(isa<SwitchInst>(Pred->getTerminator()) || | |||
| 828 | isa<IndirectBrInst>(Pred->getTerminator()))) | |||
| 829 | return true; | |||
| 830 | ||||
| 831 | if (BB->getTerminator() != BB->getFirstNonPHIOrDbg()) | |||
| 832 | return true; | |||
| 833 | ||||
| 834 | // We use a simple cost heuristic which determine skipping merging is | |||
| 835 | // profitable if the cost of skipping merging is less than the cost of | |||
| 836 | // merging : Cost(skipping merging) < Cost(merging BB), where the | |||
| 837 | // Cost(skipping merging) is Freq(BB) * (Cost(Copy) + Cost(Branch)), and | |||
| 838 | // the Cost(merging BB) is Freq(Pred) * Cost(Copy). | |||
| 839 | // Assuming Cost(Copy) == Cost(Branch), we could simplify it to : | |||
| 840 | // Freq(Pred) / Freq(BB) > 2. | |||
| 841 | // Note that if there are multiple empty blocks sharing the same incoming | |||
| 842 | // value for the PHIs in the DestBB, we consider them together. In such | |||
| 843 | // case, Cost(merging BB) will be the sum of their frequencies. | |||
| 844 | ||||
| 845 | if (!isa<PHINode>(DestBB->begin())) | |||
| 846 | return true; | |||
| 847 | ||||
| 848 | SmallPtrSet<BasicBlock *, 16> SameIncomingValueBBs; | |||
| 849 | ||||
| 850 | // Find all other incoming blocks from which incoming values of all PHIs in | |||
| 851 | // DestBB are the same as the ones from BB. | |||
| 852 | for (BasicBlock *DestBBPred : predecessors(DestBB)) { | |||
| 853 | if (DestBBPred == BB) | |||
| 854 | continue; | |||
| 855 | ||||
| 856 | if (llvm::all_of(DestBB->phis(), [&](const PHINode &DestPN) { | |||
| 857 | return DestPN.getIncomingValueForBlock(BB) == | |||
| 858 | DestPN.getIncomingValueForBlock(DestBBPred); | |||
| 859 | })) | |||
| 860 | SameIncomingValueBBs.insert(DestBBPred); | |||
| 861 | } | |||
| 862 | ||||
| 863 | // See if all BB's incoming values are same as the value from Pred. In this | |||
| 864 | // case, no reason to skip merging because COPYs are expected to be place in | |||
| 865 | // Pred already. | |||
| 866 | if (SameIncomingValueBBs.count(Pred)) | |||
| 867 | return true; | |||
| 868 | ||||
| 869 | BlockFrequency PredFreq = BFI->getBlockFreq(Pred); | |||
| 870 | BlockFrequency BBFreq = BFI->getBlockFreq(BB); | |||
| 871 | ||||
| 872 | for (auto *SameValueBB : SameIncomingValueBBs) | |||
| 873 | if (SameValueBB->getUniquePredecessor() == Pred && | |||
| 874 | DestBB == findDestBlockOfMergeableEmptyBlock(SameValueBB)) | |||
| 875 | BBFreq += BFI->getBlockFreq(SameValueBB); | |||
| 876 | ||||
| 877 | return PredFreq.getFrequency() <= | |||
| 878 | BBFreq.getFrequency() * FreqRatioToSkipMerge; | |||
| 879 | } | |||
| 880 | ||||
| 881 | /// Return true if we can merge BB into DestBB if there is a single | |||
| 882 | /// unconditional branch between them, and BB contains no other non-phi | |||
| 883 | /// instructions. | |||
| 884 | bool CodeGenPrepare::canMergeBlocks(const BasicBlock *BB, | |||
| 885 | const BasicBlock *DestBB) const { | |||
| 886 | // We only want to eliminate blocks whose phi nodes are used by phi nodes in | |||
| 887 | // the successor. If there are more complex condition (e.g. preheaders), | |||
| 888 | // don't mess around with them. | |||
| 889 | for (const PHINode &PN : BB->phis()) { | |||
| 890 | for (const User *U : PN.users()) { | |||
| 891 | const Instruction *UI = cast<Instruction>(U); | |||
| 892 | if (UI->getParent() != DestBB || !isa<PHINode>(UI)) | |||
| 893 | return false; | |||
| 894 | // If User is inside DestBB block and it is a PHINode then check | |||
| 895 | // incoming value. If incoming value is not from BB then this is | |||
| 896 | // a complex condition (e.g. preheaders) we want to avoid here. | |||
| 897 | if (UI->getParent() == DestBB) { | |||
| 898 | if (const PHINode *UPN = dyn_cast<PHINode>(UI)) | |||
| 899 | for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) { | |||
| 900 | Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I)); | |||
| 901 | if (Insn && Insn->getParent() == BB && | |||
| 902 | Insn->getParent() != UPN->getIncomingBlock(I)) | |||
| 903 | return false; | |||
| 904 | } | |||
| 905 | } | |||
| 906 | } | |||
| 907 | } | |||
| 908 | ||||
| 909 | // If BB and DestBB contain any common predecessors, then the phi nodes in BB | |||
| 910 | // and DestBB may have conflicting incoming values for the block. If so, we | |||
| 911 | // can't merge the block. | |||
| 912 | const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin()); | |||
| 913 | if (!DestBBPN) return true; // no conflict. | |||
| 914 | ||||
| 915 | // Collect the preds of BB. | |||
| 916 | SmallPtrSet<const BasicBlock*, 16> BBPreds; | |||
| 917 | if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) { | |||
| 918 | // It is faster to get preds from a PHI than with pred_iterator. | |||
| 919 | for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i) | |||
| 920 | BBPreds.insert(BBPN->getIncomingBlock(i)); | |||
| 921 | } else { | |||
| 922 | BBPreds.insert(pred_begin(BB), pred_end(BB)); | |||
| 923 | } | |||
| 924 | ||||
| 925 | // Walk the preds of DestBB. | |||
| 926 | for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) { | |||
| 927 | BasicBlock *Pred = DestBBPN->getIncomingBlock(i); | |||
| 928 | if (BBPreds.count(Pred)) { // Common predecessor? | |||
| 929 | for (const PHINode &PN : DestBB->phis()) { | |||
| 930 | const Value *V1 = PN.getIncomingValueForBlock(Pred); | |||
| 931 | const Value *V2 = PN.getIncomingValueForBlock(BB); | |||
| 932 | ||||
| 933 | // If V2 is a phi node in BB, look up what the mapped value will be. | |||
| 934 | if (const PHINode *V2PN = dyn_cast<PHINode>(V2)) | |||
| 935 | if (V2PN->getParent() == BB) | |||
| 936 | V2 = V2PN->getIncomingValueForBlock(Pred); | |||
| 937 | ||||
| 938 | // If there is a conflict, bail out. | |||
| 939 | if (V1 != V2) return false; | |||
| 940 | } | |||
| 941 | } | |||
| 942 | } | |||
| 943 | ||||
| 944 | return true; | |||
| 945 | } | |||
| 946 | ||||
| 947 | /// Eliminate a basic block that has only phi's and an unconditional branch in | |||
| 948 | /// it. | |||
| 949 | void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) { | |||
| 950 | BranchInst *BI = cast<BranchInst>(BB->getTerminator()); | |||
| 951 | BasicBlock *DestBB = BI->getSuccessor(0); | |||
| 952 | ||||
| 953 | LLVM_DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"do { } while (false) | |||
| 954 | << *BB << *DestBB)do { } while (false); | |||
| 955 | ||||
| 956 | // If the destination block has a single pred, then this is a trivial edge, | |||
| 957 | // just collapse it. | |||
| 958 | if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) { | |||
| 959 | if (SinglePred != DestBB) { | |||
| 960 | assert(SinglePred == BB &&((void)0) | |||
| 961 | "Single predecessor not the same as predecessor")((void)0); | |||
| 962 | // Merge DestBB into SinglePred/BB and delete it. | |||
| 963 | MergeBlockIntoPredecessor(DestBB); | |||
| 964 | // Note: BB(=SinglePred) will not be deleted on this path. | |||
| 965 | // DestBB(=its single successor) is the one that was deleted. | |||
| 966 | LLVM_DEBUG(dbgs() << "AFTER:\n" << *SinglePred << "\n\n\n")do { } while (false); | |||
| 967 | return; | |||
| 968 | } | |||
| 969 | } | |||
| 970 | ||||
| 971 | // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB | |||
| 972 | // to handle the new incoming edges it is about to have. | |||
| 973 | for (PHINode &PN : DestBB->phis()) { | |||
| 974 | // Remove the incoming value for BB, and remember it. | |||
| 975 | Value *InVal = PN.removeIncomingValue(BB, false); | |||
| 976 | ||||
| 977 | // Two options: either the InVal is a phi node defined in BB or it is some | |||
| 978 | // value that dominates BB. | |||
| 979 | PHINode *InValPhi = dyn_cast<PHINode>(InVal); | |||
| 980 | if (InValPhi && InValPhi->getParent() == BB) { | |||
| 981 | // Add all of the input values of the input PHI as inputs of this phi. | |||
| 982 | for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i) | |||
| 983 | PN.addIncoming(InValPhi->getIncomingValue(i), | |||
| 984 | InValPhi->getIncomingBlock(i)); | |||
| 985 | } else { | |||
| 986 | // Otherwise, add one instance of the dominating value for each edge that | |||
| 987 | // we will be adding. | |||
| 988 | if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) { | |||
| 989 | for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i) | |||
| 990 | PN.addIncoming(InVal, BBPN->getIncomingBlock(i)); | |||
| 991 | } else { | |||
| 992 | for (BasicBlock *Pred : predecessors(BB)) | |||
| 993 | PN.addIncoming(InVal, Pred); | |||
| 994 | } | |||
| 995 | } | |||
| 996 | } | |||
| 997 | ||||
| 998 | // The PHIs are now updated, change everything that refers to BB to use | |||
| 999 | // DestBB and remove BB. | |||
| 1000 | BB->replaceAllUsesWith(DestBB); | |||
| 1001 | BB->eraseFromParent(); | |||
| 1002 | ++NumBlocksElim; | |||
| 1003 | ||||
| 1004 | LLVM_DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n")do { } while (false); | |||
| 1005 | } | |||
| 1006 | ||||
| 1007 | // Computes a map of base pointer relocation instructions to corresponding | |||
| 1008 | // derived pointer relocation instructions given a vector of all relocate calls | |||
| 1009 | static void computeBaseDerivedRelocateMap( | |||
| 1010 | const SmallVectorImpl<GCRelocateInst *> &AllRelocateCalls, | |||
| 1011 | DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> | |||
| 1012 | &RelocateInstMap) { | |||
| 1013 | // Collect information in two maps: one primarily for locating the base object | |||
| 1014 | // while filling the second map; the second map is the final structure holding | |||
| 1015 | // a mapping between Base and corresponding Derived relocate calls | |||
| 1016 | DenseMap<std::pair<unsigned, unsigned>, GCRelocateInst *> RelocateIdxMap; | |||
| 1017 | for (auto *ThisRelocate : AllRelocateCalls) { | |||
| 1018 | auto K = std::make_pair(ThisRelocate->getBasePtrIndex(), | |||
| 1019 | ThisRelocate->getDerivedPtrIndex()); | |||
| 1020 | RelocateIdxMap.insert(std::make_pair(K, ThisRelocate)); | |||
| 1021 | } | |||
| 1022 | for (auto &Item : RelocateIdxMap) { | |||
| 1023 | std::pair<unsigned, unsigned> Key = Item.first; | |||
| 1024 | if (Key.first == Key.second) | |||
| 1025 | // Base relocation: nothing to insert | |||
| 1026 | continue; | |||
| 1027 | ||||
| 1028 | GCRelocateInst *I = Item.second; | |||
| 1029 | auto BaseKey = std::make_pair(Key.first, Key.first); | |||
| 1030 | ||||
| 1031 | // We're iterating over RelocateIdxMap so we cannot modify it. | |||
| 1032 | auto MaybeBase = RelocateIdxMap.find(BaseKey); | |||
| 1033 | if (MaybeBase == RelocateIdxMap.end()) | |||
| 1034 | // TODO: We might want to insert a new base object relocate and gep off | |||
| 1035 | // that, if there are enough derived object relocates. | |||
| 1036 | continue; | |||
| 1037 | ||||
| 1038 | RelocateInstMap[MaybeBase->second].push_back(I); | |||
| 1039 | } | |||
| 1040 | } | |||
| 1041 | ||||
| 1042 | // Accepts a GEP and extracts the operands into a vector provided they're all | |||
| 1043 | // small integer constants | |||
| 1044 | static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP, | |||
| 1045 | SmallVectorImpl<Value *> &OffsetV) { | |||
| 1046 | for (unsigned i = 1; i < GEP->getNumOperands(); i++) { | |||
| 1047 | // Only accept small constant integer operands | |||
| 1048 | auto *Op = dyn_cast<ConstantInt>(GEP->getOperand(i)); | |||
| 1049 | if (!Op || Op->getZExtValue() > 20) | |||
| 1050 | return false; | |||
| 1051 | } | |||
| 1052 | ||||
| 1053 | for (unsigned i = 1; i < GEP->getNumOperands(); i++) | |||
| 1054 | OffsetV.push_back(GEP->getOperand(i)); | |||
| 1055 | return true; | |||
| 1056 | } | |||
| 1057 | ||||
| 1058 | // Takes a RelocatedBase (base pointer relocation instruction) and Targets to | |||
| 1059 | // replace, computes a replacement, and affects it. | |||
| 1060 | static bool | |||
| 1061 | simplifyRelocatesOffABase(GCRelocateInst *RelocatedBase, | |||
| 1062 | const SmallVectorImpl<GCRelocateInst *> &Targets) { | |||
| 1063 | bool MadeChange = false; | |||
| 1064 | // We must ensure the relocation of derived pointer is defined after | |||
| 1065 | // relocation of base pointer. If we find a relocation corresponding to base | |||
| 1066 | // defined earlier than relocation of base then we move relocation of base | |||
| 1067 | // right before found relocation. We consider only relocation in the same | |||
| 1068 | // basic block as relocation of base. Relocations from other basic block will | |||
| 1069 | // be skipped by optimization and we do not care about them. | |||
| 1070 | for (auto R = RelocatedBase->getParent()->getFirstInsertionPt(); | |||
| 1071 | &*R != RelocatedBase; ++R) | |||
| 1072 | if (auto *RI = dyn_cast<GCRelocateInst>(R)) | |||
| 1073 | if (RI->getStatepoint() == RelocatedBase->getStatepoint()) | |||
| 1074 | if (RI->getBasePtrIndex() == RelocatedBase->getBasePtrIndex()) { | |||
| 1075 | RelocatedBase->moveBefore(RI); | |||
| 1076 | break; | |||
| 1077 | } | |||
| 1078 | ||||
| 1079 | for (GCRelocateInst *ToReplace : Targets) { | |||
| 1080 | assert(ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() &&((void)0) | |||
| 1081 | "Not relocating a derived object of the original base object")((void)0); | |||
| 1082 | if (ToReplace->getBasePtrIndex() == ToReplace->getDerivedPtrIndex()) { | |||
| 1083 | // A duplicate relocate call. TODO: coalesce duplicates. | |||
| 1084 | continue; | |||
| 1085 | } | |||
| 1086 | ||||
| 1087 | if (RelocatedBase->getParent() != ToReplace->getParent()) { | |||
| 1088 | // Base and derived relocates are in different basic blocks. | |||
| 1089 | // In this case transform is only valid when base dominates derived | |||
| 1090 | // relocate. However it would be too expensive to check dominance | |||
| 1091 | // for each such relocate, so we skip the whole transformation. | |||
| 1092 | continue; | |||
| 1093 | } | |||
| 1094 | ||||
| 1095 | Value *Base = ToReplace->getBasePtr(); | |||
| 1096 | auto *Derived = dyn_cast<GetElementPtrInst>(ToReplace->getDerivedPtr()); | |||
| 1097 | if (!Derived
| |||
| 1098 | continue; | |||
| 1099 | ||||
| 1100 | SmallVector<Value *, 2> OffsetV; | |||
| 1101 | if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV)) | |||
| 1102 | continue; | |||
| 1103 | ||||
| 1104 | // Create a Builder and replace the target callsite with a gep | |||
| 1105 | assert(RelocatedBase->getNextNode() &&((void)0) | |||
| 1106 | "Should always have one since it's not a terminator")((void)0); | |||
| 1107 | ||||
| 1108 | // Insert after RelocatedBase | |||
| 1109 | IRBuilder<> Builder(RelocatedBase->getNextNode()); | |||
| 1110 | Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc()); | |||
| 1111 | ||||
| 1112 | // If gc_relocate does not match the actual type, cast it to the right type. | |||
| 1113 | // In theory, there must be a bitcast after gc_relocate if the type does not | |||
| 1114 | // match, and we should reuse it to get the derived pointer. But it could be | |||
| 1115 | // cases like this: | |||
| 1116 | // bb1: | |||
| 1117 | // ... | |||
| 1118 | // %g1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...) | |||
| 1119 | // br label %merge | |||
| 1120 | // | |||
| 1121 | // bb2: | |||
| 1122 | // ... | |||
| 1123 | // %g2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...) | |||
| 1124 | // br label %merge | |||
| 1125 | // | |||
| 1126 | // merge: | |||
| 1127 | // %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ] | |||
| 1128 | // %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)* | |||
| 1129 | // | |||
| 1130 | // In this case, we can not find the bitcast any more. So we insert a new bitcast | |||
| 1131 | // no matter there is already one or not. In this way, we can handle all cases, and | |||
| 1132 | // the extra bitcast should be optimized away in later passes. | |||
| 1133 | Value *ActualRelocatedBase = RelocatedBase; | |||
| 1134 | if (RelocatedBase->getType() != Base->getType()) { | |||
| ||||
| 1135 | ActualRelocatedBase = | |||
| 1136 | Builder.CreateBitCast(RelocatedBase, Base->getType()); | |||
| 1137 | } | |||
| 1138 | Value *Replacement = Builder.CreateGEP( | |||
| 1139 | Derived->getSourceElementType(), ActualRelocatedBase, makeArrayRef(OffsetV)); | |||
| 1140 | Replacement->takeName(ToReplace); | |||
| 1141 | // If the newly generated derived pointer's type does not match the original derived | |||
| 1142 | // pointer's type, cast the new derived pointer to match it. Same reasoning as above. | |||
| 1143 | Value *ActualReplacement = Replacement; | |||
| 1144 | if (Replacement->getType() != ToReplace->getType()) { | |||
| 1145 | ActualReplacement = | |||
| 1146 | Builder.CreateBitCast(Replacement, ToReplace->getType()); | |||
| 1147 | } | |||
| 1148 | ToReplace->replaceAllUsesWith(ActualReplacement); | |||
| 1149 | ToReplace->eraseFromParent(); | |||
| 1150 | ||||
| 1151 | MadeChange = true; | |||
| 1152 | } | |||
| 1153 | return MadeChange; | |||
| 1154 | } | |||
| 1155 | ||||
| 1156 | // Turns this: | |||
| 1157 | // | |||
| 1158 | // %base = ... | |||
| 1159 | // %ptr = gep %base + 15 | |||
| 1160 | // %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr) | |||
| 1161 | // %base' = relocate(%tok, i32 4, i32 4) | |||
| 1162 | // %ptr' = relocate(%tok, i32 4, i32 5) | |||
| 1163 | // %val = load %ptr' | |||
| 1164 | // | |||
| 1165 | // into this: | |||
| 1166 | // | |||
| 1167 | // %base = ... | |||
| 1168 | // %ptr = gep %base + 15 | |||
| 1169 | // %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr) | |||
| 1170 | // %base' = gc.relocate(%tok, i32 4, i32 4) | |||
| 1171 | // %ptr' = gep %base' + 15 | |||
| 1172 | // %val = load %ptr' | |||
| 1173 | bool CodeGenPrepare::simplifyOffsetableRelocate(GCStatepointInst &I) { | |||
| 1174 | bool MadeChange = false; | |||
| 1175 | SmallVector<GCRelocateInst *, 2> AllRelocateCalls; | |||
| 1176 | for (auto *U : I.users()) | |||
| 1177 | if (GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U)) | |||
| 1178 | // Collect all the relocate calls associated with a statepoint | |||
| 1179 | AllRelocateCalls.push_back(Relocate); | |||
| 1180 | ||||
| 1181 | // We need at least one base pointer relocation + one derived pointer | |||
| 1182 | // relocation to mangle | |||
| 1183 | if (AllRelocateCalls.size() < 2) | |||
| ||||
| 1184 | return false; | |||
| 1185 | ||||
| 1186 | // RelocateInstMap is a mapping from the base relocate instruction to the | |||
| 1187 | // corresponding derived relocate instructions | |||
| 1188 | DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> RelocateInstMap; | |||
| 1189 | computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap); | |||
| 1190 | if (RelocateInstMap.empty()) | |||
| 1191 | return false; | |||
| 1192 | ||||
| 1193 | for (auto &Item : RelocateInstMap) | |||
| 1194 | // Item.first is the RelocatedBase to offset against | |||
| 1195 | // Item.second is the vector of Targets to replace | |||
| 1196 | MadeChange = simplifyRelocatesOffABase(Item.first, Item.second); | |||
| 1197 | return MadeChange; | |||
| 1198 | } | |||
| 1199 | ||||
| 1200 | /// Sink the specified cast instruction into its user blocks. | |||
| 1201 | static bool SinkCast(CastInst *CI) { | |||
| 1202 | BasicBlock *DefBB = CI->getParent(); | |||
| 1203 | ||||
| 1204 | /// InsertedCasts - Only insert a cast in each block once. | |||
| 1205 | DenseMap<BasicBlock*, CastInst*> InsertedCasts; | |||
| 1206 | ||||
| 1207 | bool MadeChange = false; | |||
| 1208 | for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end(); | |||
| 1209 | UI != E; ) { | |||
| 1210 | Use &TheUse = UI.getUse(); | |||
| 1211 | Instruction *User = cast<Instruction>(*UI); | |||
| 1212 | ||||
| 1213 | // Figure out which BB this cast is used in. For PHI's this is the | |||
| 1214 | // appropriate predecessor block. | |||
| 1215 | BasicBlock *UserBB = User->getParent(); | |||
| 1216 | if (PHINode *PN = dyn_cast<PHINode>(User)) { | |||
| 1217 | UserBB = PN->getIncomingBlock(TheUse); | |||
| 1218 | } | |||
| 1219 | ||||
| 1220 | // Preincrement use iterator so we don't invalidate it. | |||
| 1221 | ++UI; | |||
| 1222 | ||||
| 1223 | // The first insertion point of a block containing an EH pad is after the | |||
| 1224 | // pad. If the pad is the user, we cannot sink the cast past the pad. | |||
| 1225 | if (User->isEHPad()) | |||
| 1226 | continue; | |||
| 1227 | ||||
| 1228 | // If the block selected to receive the cast is an EH pad that does not | |||
| 1229 | // allow non-PHI instructions before the terminator, we can't sink the | |||
| 1230 | // cast. | |||
| 1231 | if (UserBB->getTerminator()->isEHPad()) | |||
| 1232 | continue; | |||
| 1233 | ||||
| 1234 | // If this user is in the same block as the cast, don't change the cast. | |||
| 1235 | if (UserBB == DefBB) continue; | |||
| 1236 | ||||
| 1237 | // If we have already inserted a cast into this block, use it. | |||
| 1238 | CastInst *&InsertedCast = InsertedCasts[UserBB]; | |||
| 1239 | ||||
| 1240 | if (!InsertedCast) { | |||
| 1241 | BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt(); | |||
| 1242 | assert(InsertPt != UserBB->end())((void)0); | |||
| 1243 | InsertedCast = CastInst::Create(CI->getOpcode(), CI->getOperand(0), | |||
| 1244 | CI->getType(), "", &*InsertPt); | |||
| 1245 | InsertedCast->setDebugLoc(CI->getDebugLoc()); | |||
| 1246 | } | |||
| 1247 | ||||
| 1248 | // Replace a use of the cast with a use of the new cast. | |||
| 1249 | TheUse = InsertedCast; | |||
| 1250 | MadeChange = true; | |||
| 1251 | ++NumCastUses; | |||
| 1252 | } | |||
| 1253 | ||||
| 1254 | // If we removed all uses, nuke the cast. | |||
| 1255 | if (CI->use_empty()) { | |||
| 1256 | salvageDebugInfo(*CI); | |||
| 1257 | CI->eraseFromParent(); | |||
| 1258 | MadeChange = true; | |||
| 1259 | } | |||
| 1260 | ||||
| 1261 | return MadeChange; | |||
| 1262 | } | |||
| 1263 | ||||
| 1264 | /// If the specified cast instruction is a noop copy (e.g. it's casting from | |||
| 1265 | /// one pointer type to another, i32->i8 on PPC), sink it into user blocks to | |||
| 1266 | /// reduce the number of virtual registers that must be created and coalesced. | |||
| 1267 | /// | |||
| 1268 | /// Return true if any changes are made. | |||
| 1269 | static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI, | |||
| 1270 | const DataLayout &DL) { | |||
| 1271 | // Sink only "cheap" (or nop) address-space casts. This is a weaker condition | |||
| 1272 | // than sinking only nop casts, but is helpful on some platforms. | |||
| 1273 | if (auto *ASC = dyn_cast<AddrSpaceCastInst>(CI)) { | |||
| 1274 | if (!TLI.isFreeAddrSpaceCast(ASC->getSrcAddressSpace(), | |||
| 1275 | ASC->getDestAddressSpace())) | |||
| 1276 | return false; | |||
| 1277 | } | |||
| 1278 | ||||
| 1279 | // If this is a noop copy, | |||
| 1280 | EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType()); | |||
| 1281 | EVT DstVT = TLI.getValueType(DL, CI->getType()); | |||
| 1282 | ||||
| 1283 | // This is an fp<->int conversion? | |||
| 1284 | if (SrcVT.isInteger() != DstVT.isInteger()) | |||
| 1285 | return false; | |||
| 1286 | ||||
| 1287 | // If this is an extension, it will be a zero or sign extension, which | |||
| 1288 | // isn't a noop. | |||
| 1289 | if (SrcVT.bitsLT(DstVT)) return false; | |||
| 1290 | ||||
| 1291 | // If these values will be promoted, find out what they will be promoted | |||
| 1292 | // to. This helps us consider truncates on PPC as noop copies when they | |||
| 1293 | // are. | |||
| 1294 | if (TLI.getTypeAction(CI->getContext(), SrcVT) == | |||
| 1295 | TargetLowering::TypePromoteInteger) | |||
| 1296 | SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT); | |||
| 1297 | if (TLI.getTypeAction(CI->getContext(), DstVT) == | |||
| 1298 | TargetLowering::TypePromoteInteger) | |||
| 1299 | DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT); | |||
| 1300 | ||||
| 1301 | // If, after promotion, these are the same types, this is a noop copy. | |||
| 1302 | if (SrcVT != DstVT) | |||
| 1303 | return false; | |||
| 1304 | ||||
| 1305 | return SinkCast(CI); | |||
| 1306 | } | |||
| 1307 | ||||
| 1308 | // Match a simple increment by constant operation. Note that if a sub is | |||
| 1309 | // matched, the step is negated (as if the step had been canonicalized to | |||
| 1310 | // an add, even though we leave the instruction alone.) | |||
| 1311 | bool matchIncrement(const Instruction* IVInc, Instruction *&LHS, | |||
| 1312 | Constant *&Step) { | |||
| 1313 | if (match(IVInc, m_Add(m_Instruction(LHS), m_Constant(Step))) || | |||
| 1314 | match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::uadd_with_overflow>( | |||
| 1315 | m_Instruction(LHS), m_Constant(Step))))) | |||
| 1316 | return true; | |||
| 1317 | if (match(IVInc, m_Sub(m_Instruction(LHS), m_Constant(Step))) || | |||
| 1318 | match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::usub_with_overflow>( | |||
| 1319 | m_Instruction(LHS), m_Constant(Step))))) { | |||
| 1320 | Step = ConstantExpr::getNeg(Step); | |||
| 1321 | return true; | |||
| 1322 | } | |||
| 1323 | return false; | |||
| 1324 | } | |||
| 1325 | ||||
| 1326 | /// If given \p PN is an inductive variable with value IVInc coming from the | |||
| 1327 | /// backedge, and on each iteration it gets increased by Step, return pair | |||
| 1328 | /// <IVInc, Step>. Otherwise, return None. | |||
| 1329 | static Optional<std::pair<Instruction *, Constant *> > | |||
| 1330 | getIVIncrement(const PHINode *PN, const LoopInfo *LI) { | |||
| 1331 | const Loop *L = LI->getLoopFor(PN->getParent()); | |||
| 1332 | if (!L || L->getHeader() != PN->getParent() || !L->getLoopLatch()) | |||
| 1333 | return None; | |||
| 1334 | auto *IVInc = | |||
| 1335 | dyn_cast<Instruction>(PN->getIncomingValueForBlock(L->getLoopLatch())); | |||
| 1336 | if (!IVInc || LI->getLoopFor(IVInc->getParent()) != L) | |||
| 1337 | return None; | |||
| 1338 | Instruction *LHS = nullptr; | |||
| 1339 | Constant *Step = nullptr; | |||
| 1340 | if (matchIncrement(IVInc, LHS, Step) && LHS == PN) | |||
| 1341 | return std::make_pair(IVInc, Step); | |||
| 1342 | return None; | |||
| 1343 | } | |||
| 1344 | ||||
| 1345 | static bool isIVIncrement(const Value *V, const LoopInfo *LI) { | |||
| 1346 | auto *I = dyn_cast<Instruction>(V); | |||
| 1347 | if (!I) | |||
| 1348 | return false; | |||
| 1349 | Instruction *LHS = nullptr; | |||
| 1350 | Constant *Step = nullptr; | |||
| 1351 | if (!matchIncrement(I, LHS, Step)) | |||
| 1352 | return false; | |||
| 1353 | if (auto *PN = dyn_cast<PHINode>(LHS)) | |||
| 1354 | if (auto IVInc = getIVIncrement(PN, LI)) | |||
| 1355 | return IVInc->first == I; | |||
| 1356 | return false; | |||
| 1357 | } | |||
| 1358 | ||||
| 1359 | bool CodeGenPrepare::replaceMathCmpWithIntrinsic(BinaryOperator *BO, | |||
| 1360 | Value *Arg0, Value *Arg1, | |||
| 1361 | CmpInst *Cmp, | |||
| 1362 | Intrinsic::ID IID) { | |||
| 1363 | auto IsReplacableIVIncrement = [this, &Cmp](BinaryOperator *BO) { | |||
| 1364 | if (!isIVIncrement(BO, LI)) | |||
| 1365 | return false; | |||
| 1366 | const Loop *L = LI->getLoopFor(BO->getParent()); | |||
| 1367 | assert(L && "L should not be null after isIVIncrement()")((void)0); | |||
| 1368 | // Do not risk on moving increment into a child loop. | |||
| 1369 | if (LI->getLoopFor(Cmp->getParent()) != L) | |||
| 1370 | return false; | |||
| 1371 | ||||
| 1372 | // Finally, we need to ensure that the insert point will dominate all | |||
| 1373 | // existing uses of the increment. | |||
| 1374 | ||||
| 1375 | auto &DT = getDT(*BO->getParent()->getParent()); | |||
| 1376 | if (DT.dominates(Cmp->getParent(), BO->getParent())) | |||
| 1377 | // If we're moving up the dom tree, all uses are trivially dominated. | |||
| 1378 | // (This is the common case for code produced by LSR.) | |||
| 1379 | return true; | |||
| 1380 | ||||
| 1381 | // Otherwise, special case the single use in the phi recurrence. | |||
| 1382 | return BO->hasOneUse() && DT.dominates(Cmp->getParent(), L->getLoopLatch()); | |||
| 1383 | }; | |||
| 1384 | if (BO->getParent() != Cmp->getParent() && !IsReplacableIVIncrement(BO)) { | |||
| 1385 | // We used to use a dominator tree here to allow multi-block optimization. | |||
| 1386 | // But that was problematic because: | |||
| 1387 | // 1. It could cause a perf regression by hoisting the math op into the | |||
| 1388 | // critical path. | |||
| 1389 | // 2. It could cause a perf regression by creating a value that was live | |||
| 1390 | // across multiple blocks and increasing register pressure. | |||
| 1391 | // 3. Use of a dominator tree could cause large compile-time regression. | |||
| 1392 | // This is because we recompute the DT on every change in the main CGP | |||
| 1393 | // run-loop. The recomputing is probably unnecessary in many cases, so if | |||
| 1394 | // that was fixed, using a DT here would be ok. | |||
| 1395 | // | |||
| 1396 | // There is one important particular case we still want to handle: if BO is | |||
| 1397 | // the IV increment. Important properties that make it profitable: | |||
| 1398 | // - We can speculate IV increment anywhere in the loop (as long as the | |||
| 1399 | // indvar Phi is its only user); | |||
| 1400 | // - Upon computing Cmp, we effectively compute something equivalent to the | |||
| 1401 | // IV increment (despite it loops differently in the IR). So moving it up | |||
| 1402 | // to the cmp point does not really increase register pressure. | |||
| 1403 | return false; | |||
| 1404 | } | |||
| 1405 | ||||
| 1406 | // We allow matching the canonical IR (add X, C) back to (usubo X, -C). | |||
| 1407 | if (BO->getOpcode() == Instruction::Add && | |||
| 1408 | IID == Intrinsic::usub_with_overflow) { | |||
| 1409 | assert(isa<Constant>(Arg1) && "Unexpected input for usubo")((void)0); | |||
| 1410 | Arg1 = ConstantExpr::getNeg(cast<Constant>(Arg1)); | |||
| 1411 | } | |||
| 1412 | ||||
| 1413 | // Insert at the first instruction of the pair. | |||
| 1414 | Instruction *InsertPt = nullptr; | |||
| 1415 | for (Instruction &Iter : *Cmp->getParent()) { | |||
| 1416 | // If BO is an XOR, it is not guaranteed that it comes after both inputs to | |||
| 1417 | // the overflow intrinsic are defined. | |||
| 1418 | if ((BO->getOpcode() != Instruction::Xor && &Iter == BO) || &Iter == Cmp) { | |||
| 1419 | InsertPt = &Iter; | |||
| 1420 | break; | |||
| 1421 | } | |||
| 1422 | } | |||
| 1423 | assert(InsertPt != nullptr && "Parent block did not contain cmp or binop")((void)0); | |||
| 1424 | ||||
| 1425 | IRBuilder<> Builder(InsertPt); | |||
| 1426 | Value *MathOV = Builder.CreateBinaryIntrinsic(IID, Arg0, Arg1); | |||
| 1427 | if (BO->getOpcode() != Instruction::Xor) { | |||
| 1428 | Value *Math = Builder.CreateExtractValue(MathOV, 0, "math"); | |||
| 1429 | BO->replaceAllUsesWith(Math); | |||
| 1430 | } else | |||
| 1431 | assert(BO->hasOneUse() &&((void)0) | |||
| 1432 | "Patterns with XOr should use the BO only in the compare")((void)0); | |||
| 1433 | Value *OV = Builder.CreateExtractValue(MathOV, 1, "ov"); | |||
| 1434 | Cmp->replaceAllUsesWith(OV); | |||
| 1435 | Cmp->eraseFromParent(); | |||
| 1436 | BO->eraseFromParent(); | |||
| 1437 | return true; | |||
| 1438 | } | |||
| 1439 | ||||
| 1440 | /// Match special-case patterns that check for unsigned add overflow. | |||
| 1441 | static bool matchUAddWithOverflowConstantEdgeCases(CmpInst *Cmp, | |||
| 1442 | BinaryOperator *&Add) { | |||
| 1443 | // Add = add A, 1; Cmp = icmp eq A,-1 (overflow if A is max val) | |||
| 1444 | // Add = add A,-1; Cmp = icmp ne A, 0 (overflow if A is non-zero) | |||
| 1445 | Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1); | |||
| 1446 | ||||
| 1447 | // We are not expecting non-canonical/degenerate code. Just bail out. | |||
| 1448 | if (isa<Constant>(A)) | |||
| 1449 | return false; | |||
| 1450 | ||||
| 1451 | ICmpInst::Predicate Pred = Cmp->getPredicate(); | |||
| 1452 | if (Pred == ICmpInst::ICMP_EQ && match(B, m_AllOnes())) | |||
| 1453 | B = ConstantInt::get(B->getType(), 1); | |||
| 1454 | else if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt())) | |||
| 1455 | B = ConstantInt::get(B->getType(), -1); | |||
| 1456 | else | |||
| 1457 | return false; | |||
| 1458 | ||||
| 1459 | // Check the users of the variable operand of the compare looking for an add | |||
| 1460 | // with the adjusted constant. | |||
| 1461 | for (User *U : A->users()) { | |||
| 1462 | if (match(U, m_Add(m_Specific(A), m_Specific(B)))) { | |||
| 1463 | Add = cast<BinaryOperator>(U); | |||
| 1464 | return true; | |||
| 1465 | } | |||
| 1466 | } | |||
| 1467 | return false; | |||
| 1468 | } | |||
| 1469 | ||||
| 1470 | /// Try to combine the compare into a call to the llvm.uadd.with.overflow | |||
| 1471 | /// intrinsic. Return true if any changes were made. | |||
| 1472 | bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp, | |||
| 1473 | bool &ModifiedDT) { | |||
| 1474 | Value *A, *B; | |||
| 1475 | BinaryOperator *Add; | |||
| 1476 | if (!match(Cmp, m_UAddWithOverflow(m_Value(A), m_Value(B), m_BinOp(Add)))) { | |||
| 1477 | if (!matchUAddWithOverflowConstantEdgeCases(Cmp, Add)) | |||
| 1478 | return false; | |||
| 1479 | // Set A and B in case we match matchUAddWithOverflowConstantEdgeCases. | |||
| 1480 | A = Add->getOperand(0); | |||
| 1481 | B = Add->getOperand(1); | |||
| 1482 | } | |||
| 1483 | ||||
| 1484 | if (!TLI->shouldFormOverflowOp(ISD::UADDO, | |||
| 1485 | TLI->getValueType(*DL, Add->getType()), | |||
| 1486 | Add->hasNUsesOrMore(2))) | |||
| 1487 | return false; | |||
| 1488 | ||||
| 1489 | // We don't want to move around uses of condition values this late, so we | |||
| 1490 | // check if it is legal to create the call to the intrinsic in the basic | |||
| 1491 | // block containing the icmp. | |||
| 1492 | if (Add->getParent() != Cmp->getParent() && !Add->hasOneUse()) | |||
| 1493 | return false; | |||
| 1494 | ||||
| 1495 | if (!replaceMathCmpWithIntrinsic(Add, A, B, Cmp, | |||
| 1496 | Intrinsic::uadd_with_overflow)) | |||
| 1497 | return false; | |||
| 1498 | ||||
| 1499 | // Reset callers - do not crash by iterating over a dead instruction. | |||
| 1500 | ModifiedDT = true; | |||
| 1501 | return true; | |||
| 1502 | } | |||
| 1503 | ||||
| 1504 | bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp, | |||
| 1505 | bool &ModifiedDT) { | |||
| 1506 | // We are not expecting non-canonical/degenerate code. Just bail out. | |||
| 1507 | Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1); | |||
| 1508 | if (isa<Constant>(A) && isa<Constant>(B)) | |||
| 1509 | return false; | |||
| 1510 | ||||
| 1511 | // Convert (A u> B) to (A u< B) to simplify pattern matching. | |||
| 1512 | ICmpInst::Predicate Pred = Cmp->getPredicate(); | |||
| 1513 | if (Pred == ICmpInst::ICMP_UGT) { | |||
| 1514 | std::swap(A, B); | |||
| 1515 | Pred = ICmpInst::ICMP_ULT; | |||
| 1516 | } | |||
| 1517 | // Convert special-case: (A == 0) is the same as (A u< 1). | |||
| 1518 | if (Pred == ICmpInst::ICMP_EQ && match(B, m_ZeroInt())) { | |||
| 1519 | B = ConstantInt::get(B->getType(), 1); | |||
| 1520 | Pred = ICmpInst::ICMP_ULT; | |||
| 1521 | } | |||
| 1522 | // Convert special-case: (A != 0) is the same as (0 u< A). | |||
| 1523 | if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt())) { | |||
| 1524 | std::swap(A, B); | |||
| 1525 | Pred = ICmpInst::ICMP_ULT; | |||
| 1526 | } | |||
| 1527 | if (Pred != ICmpInst::ICMP_ULT) | |||
| 1528 | return false; | |||
| 1529 | ||||
| 1530 | // Walk the users of a variable operand of a compare looking for a subtract or | |||
| 1531 | // add with that same operand. Also match the 2nd operand of the compare to | |||
| 1532 | // the add/sub, but that may be a negated constant operand of an add. | |||
| 1533 | Value *CmpVariableOperand = isa<Constant>(A) ? B : A; | |||
| 1534 | BinaryOperator *Sub = nullptr; | |||
| 1535 | for (User *U : CmpVariableOperand->users()) { | |||
| 1536 | // A - B, A u< B --> usubo(A, B) | |||
| 1537 | if (match(U, m_Sub(m_Specific(A), m_Specific(B)))) { | |||
| 1538 | Sub = cast<BinaryOperator>(U); | |||
| 1539 | break; | |||
| 1540 | } | |||
| 1541 | ||||
| 1542 | // A + (-C), A u< C (canonicalized form of (sub A, C)) | |||
| 1543 | const APInt *CmpC, *AddC; | |||
| 1544 | if (match(U, m_Add(m_Specific(A), m_APInt(AddC))) && | |||
| 1545 | match(B, m_APInt(CmpC)) && *AddC == -(*CmpC)) { | |||
| 1546 | Sub = cast<BinaryOperator>(U); | |||
| 1547 | break; | |||
| 1548 | } | |||
| 1549 | } | |||
| 1550 | if (!Sub) | |||
| 1551 | return false; | |||
| 1552 | ||||
| 1553 | if (!TLI->shouldFormOverflowOp(ISD::USUBO, | |||
| 1554 | TLI->getValueType(*DL, Sub->getType()), | |||
| 1555 | Sub->hasNUsesOrMore(2))) | |||
| 1556 | return false; | |||
| 1557 | ||||
| 1558 | if (!replaceMathCmpWithIntrinsic(Sub, Sub->getOperand(0), Sub->getOperand(1), | |||
| 1559 | Cmp, Intrinsic::usub_with_overflow)) | |||
| 1560 | return false; | |||
| 1561 | ||||
| 1562 | // Reset callers - do not crash by iterating over a dead instruction. | |||
| 1563 | ModifiedDT = true; | |||
| 1564 | return true; | |||
| 1565 | } | |||
| 1566 | ||||
| 1567 | /// Sink the given CmpInst into user blocks to reduce the number of virtual | |||
| 1568 | /// registers that must be created and coalesced. This is a clear win except on | |||
| 1569 | /// targets with multiple condition code registers (PowerPC), where it might | |||
| 1570 | /// lose; some adjustment may be wanted there. | |||
| 1571 | /// | |||
| 1572 | /// Return true if any changes are made. | |||
| 1573 | static bool sinkCmpExpression(CmpInst *Cmp, const TargetLowering &TLI) { | |||
| 1574 | if (TLI.hasMultipleConditionRegisters()) | |||
| 1575 | return false; | |||
| 1576 | ||||
| 1577 | // Avoid sinking soft-FP comparisons, since this can move them into a loop. | |||
| 1578 | if (TLI.useSoftFloat() && isa<FCmpInst>(Cmp)) | |||
| 1579 | return false; | |||
| 1580 | ||||
| 1581 | // Only insert a cmp in each block once. | |||
| 1582 | DenseMap<BasicBlock*, CmpInst*> InsertedCmps; | |||
| 1583 | ||||
| 1584 | bool MadeChange = false; | |||
| 1585 | for (Value::user_iterator UI = Cmp->user_begin(), E = Cmp->user_end(); | |||
| 1586 | UI != E; ) { | |||
| 1587 | Use &TheUse = UI.getUse(); | |||
| 1588 | Instruction *User = cast<Instruction>(*UI); | |||
| 1589 | ||||
| 1590 | // Preincrement use iterator so we don't invalidate it. | |||
| 1591 | ++UI; | |||
| 1592 | ||||
| 1593 | // Don't bother for PHI nodes. | |||
| 1594 | if (isa<PHINode>(User)) | |||
| 1595 | continue; | |||
| 1596 | ||||
| 1597 | // Figure out which BB this cmp is used in. | |||
| 1598 | BasicBlock *UserBB = User->getParent(); | |||
| 1599 | BasicBlock *DefBB = Cmp->getParent(); | |||
| 1600 | ||||
| 1601 | // If this user is in the same block as the cmp, don't change the cmp. | |||
| 1602 | if (UserBB == DefBB) continue; | |||
| 1603 | ||||
| 1604 | // If we have already inserted a cmp into this block, use it. | |||
| 1605 | CmpInst *&InsertedCmp = InsertedCmps[UserBB]; | |||
| 1606 | ||||
| 1607 | if (!InsertedCmp) { | |||
| 1608 | BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt(); | |||
| 1609 | assert(InsertPt != UserBB->end())((void)0); | |||
| 1610 | InsertedCmp = | |||
| 1611 | CmpInst::Create(Cmp->getOpcode(), Cmp->getPredicate(), | |||
| 1612 | Cmp->getOperand(0), Cmp->getOperand(1), "", | |||
| 1613 | &*InsertPt); | |||
| 1614 | // Propagate the debug info. | |||
| 1615 | InsertedCmp->setDebugLoc(Cmp->getDebugLoc()); | |||
| 1616 | } | |||
| 1617 | ||||
| 1618 | // Replace a use of the cmp with a use of the new cmp. | |||
| 1619 | TheUse = InsertedCmp; | |||
| 1620 | MadeChange = true; | |||
| 1621 | ++NumCmpUses; | |||
| 1622 | } | |||
| 1623 | ||||
| 1624 | // If we removed all uses, nuke the cmp. | |||
| 1625 | if (Cmp->use_empty()) { | |||
| 1626 | Cmp->eraseFromParent(); | |||
| 1627 | MadeChange = true; | |||
| 1628 | } | |||
| 1629 | ||||
| 1630 | return MadeChange; | |||
| 1631 | } | |||
| 1632 | ||||
| 1633 | /// For pattern like: | |||
| 1634 | /// | |||
| 1635 | /// DomCond = icmp sgt/slt CmpOp0, CmpOp1 (might not be in DomBB) | |||
| 1636 | /// ... | |||
| 1637 | /// DomBB: | |||
| 1638 | /// ... | |||
| 1639 | /// br DomCond, TrueBB, CmpBB | |||
| 1640 | /// CmpBB: (with DomBB being the single predecessor) | |||
| 1641 | /// ... | |||
| 1642 | /// Cmp = icmp eq CmpOp0, CmpOp1 | |||
| 1643 | /// ... | |||
| 1644 | /// | |||
| 1645 | /// It would use two comparison on targets that lowering of icmp sgt/slt is | |||
| 1646 | /// different from lowering of icmp eq (PowerPC). This function try to convert | |||
| 1647 | /// 'Cmp = icmp eq CmpOp0, CmpOp1' to ' Cmp = icmp slt/sgt CmpOp0, CmpOp1'. | |||
| 1648 | /// After that, DomCond and Cmp can use the same comparison so reduce one | |||
| 1649 | /// comparison. | |||
| 1650 | /// | |||
| 1651 | /// Return true if any changes are made. | |||
| 1652 | static bool foldICmpWithDominatingICmp(CmpInst *Cmp, | |||
| 1653 | const TargetLowering &TLI) { | |||
| 1654 | if (!EnableICMP_EQToICMP_ST && TLI.isEqualityCmpFoldedWithSignedCmp()) | |||
| 1655 | return false; | |||
| 1656 | ||||
| 1657 | ICmpInst::Predicate Pred = Cmp->getPredicate(); | |||
| 1658 | if (Pred != ICmpInst::ICMP_EQ) | |||
| 1659 | return false; | |||
| 1660 | ||||
| 1661 | // If icmp eq has users other than BranchInst and SelectInst, converting it to | |||
| 1662 | // icmp slt/sgt would introduce more redundant LLVM IR. | |||
| 1663 | for (User *U : Cmp->users()) { | |||
| 1664 | if (isa<BranchInst>(U)) | |||
| 1665 | continue; | |||
| 1666 | if (isa<SelectInst>(U) && cast<SelectInst>(U)->getCondition() == Cmp) | |||
| 1667 | continue; | |||
| 1668 | return false; | |||
| 1669 | } | |||
| 1670 | ||||
| 1671 | // This is a cheap/incomplete check for dominance - just match a single | |||
| 1672 | // predecessor with a conditional branch. | |||
| 1673 | BasicBlock *CmpBB = Cmp->getParent(); | |||
| 1674 | BasicBlock *DomBB = CmpBB->getSinglePredecessor(); | |||
| 1675 | if (!DomBB) | |||
| 1676 | return false; | |||
| 1677 | ||||
| 1678 | // We want to ensure that the only way control gets to the comparison of | |||
| 1679 | // interest is that a less/greater than comparison on the same operands is | |||
| 1680 | // false. | |||
| 1681 | Value *DomCond; | |||
| 1682 | BasicBlock *TrueBB, *FalseBB; | |||
| 1683 | if (!match(DomBB->getTerminator(), m_Br(m_Value(DomCond), TrueBB, FalseBB))) | |||
| 1684 | return false; | |||
| 1685 | if (CmpBB != FalseBB) | |||
| 1686 | return false; | |||
| 1687 | ||||
| 1688 | Value *CmpOp0 = Cmp->getOperand(0), *CmpOp1 = Cmp->getOperand(1); | |||
| 1689 | ICmpInst::Predicate DomPred; | |||
| 1690 | if (!match(DomCond, m_ICmp(DomPred, m_Specific(CmpOp0), m_Specific(CmpOp1)))) | |||
| 1691 | return false; | |||
| 1692 | if (DomPred != ICmpInst::ICMP_SGT && DomPred != ICmpInst::ICMP_SLT) | |||
| 1693 | return false; | |||
| 1694 | ||||
| 1695 | // Convert the equality comparison to the opposite of the dominating | |||
| 1696 | // comparison and swap the direction for all branch/select users. | |||
| 1697 | // We have conceptually converted: | |||
| 1698 | // Res = (a < b) ? <LT_RES> : (a == b) ? <EQ_RES> : <GT_RES>; | |||
| 1699 | // to | |||
| 1700 | // Res = (a < b) ? <LT_RES> : (a > b) ? <GT_RES> : <EQ_RES>; | |||
| 1701 | // And similarly for branches. | |||
| 1702 | for (User *U : Cmp->users()) { | |||
| 1703 | if (auto *BI = dyn_cast<BranchInst>(U)) { | |||
| 1704 | assert(BI->isConditional() && "Must be conditional")((void)0); | |||
| 1705 | BI->swapSuccessors(); | |||
| 1706 | continue; | |||
| 1707 | } | |||
| 1708 | if (auto *SI = dyn_cast<SelectInst>(U)) { | |||
| 1709 | // Swap operands | |||
| 1710 | SI->swapValues(); | |||
| 1711 | SI->swapProfMetadata(); | |||
| 1712 | continue; | |||
| 1713 | } | |||
| 1714 | llvm_unreachable("Must be a branch or a select")__builtin_unreachable(); | |||
| 1715 | } | |||
| 1716 | Cmp->setPredicate(CmpInst::getSwappedPredicate(DomPred)); | |||
| 1717 | return true; | |||
| 1718 | } | |||
| 1719 | ||||
| 1720 | bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp, bool &ModifiedDT) { | |||
| 1721 | if (sinkCmpExpression(Cmp, *TLI)) | |||
| 1722 | return true; | |||
| 1723 | ||||
| 1724 | if (combineToUAddWithOverflow(Cmp, ModifiedDT)) | |||
| 1725 | return true; | |||
| 1726 | ||||
| 1727 | if (combineToUSubWithOverflow(Cmp, ModifiedDT)) | |||
| 1728 | return true; | |||
| 1729 | ||||
| 1730 | if (foldICmpWithDominatingICmp(Cmp, *TLI)) | |||
| 1731 | return true; | |||
| 1732 | ||||
| 1733 | return false; | |||
| 1734 | } | |||
| 1735 | ||||
| 1736 | /// Duplicate and sink the given 'and' instruction into user blocks where it is | |||
| 1737 | /// used in a compare to allow isel to generate better code for targets where | |||
| 1738 | /// this operation can be combined. | |||
| 1739 | /// | |||
| 1740 | /// Return true if any changes are made. | |||
| 1741 | static bool sinkAndCmp0Expression(Instruction *AndI, | |||
| 1742 | const TargetLowering &TLI, | |||
| 1743 | SetOfInstrs &InsertedInsts) { | |||
| 1744 | // Double-check that we're not trying to optimize an instruction that was | |||
| 1745 | // already optimized by some other part of this pass. | |||
| 1746 | assert(!InsertedInsts.count(AndI) &&((void)0) | |||
| 1747 | "Attempting to optimize already optimized and instruction")((void)0); | |||
| 1748 | (void) InsertedInsts; | |||
| 1749 | ||||
| 1750 | // Nothing to do for single use in same basic block. | |||
| 1751 | if (AndI->hasOneUse() && | |||
| 1752 | AndI->getParent() == cast<Instruction>(*AndI->user_begin())->getParent()) | |||
| 1753 | return false; | |||
| 1754 | ||||
| 1755 | // Try to avoid cases where sinking/duplicating is likely to increase register | |||
| 1756 | // pressure. | |||
| 1757 | if (!isa<ConstantInt>(AndI->getOperand(0)) && | |||
| 1758 | !isa<ConstantInt>(AndI->getOperand(1)) && | |||
| 1759 | AndI->getOperand(0)->hasOneUse() && AndI->getOperand(1)->hasOneUse()) | |||
| 1760 | return false; | |||
| 1761 | ||||
| 1762 | for (auto *U : AndI->users()) { | |||
| 1763 | Instruction *User = cast<Instruction>(U); | |||
| 1764 | ||||
| 1765 | // Only sink 'and' feeding icmp with 0. | |||
| 1766 | if (!isa<ICmpInst>(User)) | |||
| 1767 | return false; | |||
| 1768 | ||||
| 1769 | auto *CmpC = dyn_cast<ConstantInt>(User->getOperand(1)); | |||
| 1770 | if (!CmpC || !CmpC->isZero()) | |||
| 1771 | return false; | |||
| 1772 | } | |||
| 1773 | ||||
| 1774 | if (!TLI.isMaskAndCmp0FoldingBeneficial(*AndI)) | |||
| 1775 | return false; | |||
| 1776 | ||||
| 1777 | LLVM_DEBUG(dbgs() << "found 'and' feeding only icmp 0;\n")do { } while (false); | |||
| 1778 | LLVM_DEBUG(AndI->getParent()->dump())do { } while (false); | |||
| 1779 | ||||
| 1780 | // Push the 'and' into the same block as the icmp 0. There should only be | |||
| 1781 | // one (icmp (and, 0)) in each block, since CSE/GVN should have removed any | |||
| 1782 | // others, so we don't need to keep track of which BBs we insert into. | |||
| 1783 | for (Value::user_iterator UI = AndI->user_begin(), E = AndI->user_end(); | |||
| 1784 | UI != E; ) { | |||
| 1785 | Use &TheUse = UI.getUse(); | |||
| 1786 | Instruction *User = cast<Instruction>(*UI); | |||
| 1787 | ||||
| 1788 | // Preincrement use iterator so we don't invalidate it. | |||
| 1789 | ++UI; | |||
| 1790 | ||||
| 1791 | LLVM_DEBUG(dbgs() << "sinking 'and' use: " << *User << "\n")do { } while (false); | |||
| 1792 | ||||
| 1793 | // Keep the 'and' in the same place if the use is already in the same block. | |||
| 1794 | Instruction *InsertPt = | |||
| 1795 | User->getParent() == AndI->getParent() ? AndI : User; | |||
| 1796 | Instruction *InsertedAnd = | |||
| 1797 | BinaryOperator::Create(Instruction::And, AndI->getOperand(0), | |||
| 1798 | AndI->getOperand(1), "", InsertPt); | |||
| 1799 | // Propagate the debug info. | |||
| 1800 | InsertedAnd->setDebugLoc(AndI->getDebugLoc()); | |||
| 1801 | ||||
| 1802 | // Replace a use of the 'and' with a use of the new 'and'. | |||
| 1803 | TheUse = InsertedAnd; | |||
| 1804 | ++NumAndUses; | |||
| 1805 | LLVM_DEBUG(User->getParent()->dump())do { } while (false); | |||
| 1806 | } | |||
| 1807 | ||||
| 1808 | // We removed all uses, nuke the and. | |||
| 1809 | AndI->eraseFromParent(); | |||
| 1810 | return true; | |||
| 1811 | } | |||
| 1812 | ||||
| 1813 | /// Check if the candidates could be combined with a shift instruction, which | |||
| 1814 | /// includes: | |||
| 1815 | /// 1. Truncate instruction | |||
| 1816 | /// 2. And instruction and the imm is a mask of the low bits: | |||
| 1817 | /// imm & (imm+1) == 0 | |||
| 1818 | static bool isExtractBitsCandidateUse(Instruction *User) { | |||
| 1819 | if (!isa<TruncInst>(User)) { | |||
| 1820 | if (User->getOpcode() != Instruction::And || | |||
| 1821 | !isa<ConstantInt>(User->getOperand(1))) | |||
| 1822 | return false; | |||
| 1823 | ||||
| 1824 | const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue(); | |||
| 1825 | ||||
| 1826 | if ((Cimm & (Cimm + 1)).getBoolValue()) | |||
| 1827 | return false; | |||
| 1828 | } | |||
| 1829 | return true; | |||
| 1830 | } | |||
| 1831 | ||||
| 1832 | /// Sink both shift and truncate instruction to the use of truncate's BB. | |||
| 1833 | static bool | |||
| 1834 | SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI, | |||
| 1835 | DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts, | |||
| 1836 | const TargetLowering &TLI, const DataLayout &DL) { | |||
| 1837 | BasicBlock *UserBB = User->getParent(); | |||
| 1838 | DenseMap<BasicBlock *, CastInst *> InsertedTruncs; | |||
| 1839 | auto *TruncI = cast<TruncInst>(User); | |||
| 1840 | bool MadeChange = false; | |||
| 1841 | ||||
| 1842 | for (Value::user_iterator TruncUI = TruncI->user_begin(), | |||
| 1843 | TruncE = TruncI->user_end(); | |||
| 1844 | TruncUI != TruncE;) { | |||
| 1845 | ||||
| 1846 | Use &TruncTheUse = TruncUI.getUse(); | |||
| 1847 | Instruction *TruncUser = cast<Instruction>(*TruncUI); | |||
| 1848 | // Preincrement use iterator so we don't invalidate it. | |||
| 1849 | ||||
| 1850 | ++TruncUI; | |||
| 1851 | ||||
| 1852 | int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode()); | |||
| 1853 | if (!ISDOpcode) | |||
| 1854 | continue; | |||
| 1855 | ||||
| 1856 | // If the use is actually a legal node, there will not be an | |||
| 1857 | // implicit truncate. | |||
| 1858 | // FIXME: always querying the result type is just an | |||
| 1859 | // approximation; some nodes' legality is determined by the | |||
| 1860 | // operand or other means. There's no good way to find out though. | |||
| 1861 | if (TLI.isOperationLegalOrCustom( | |||
| 1862 | ISDOpcode, TLI.getValueType(DL, TruncUser->getType(), true))) | |||
| 1863 | continue; | |||
| 1864 | ||||
| 1865 | // Don't bother for PHI nodes. | |||
| 1866 | if (isa<PHINode>(TruncUser)) | |||
| 1867 | continue; | |||
| 1868 | ||||
| 1869 | BasicBlock *TruncUserBB = TruncUser->getParent(); | |||
| 1870 | ||||
| 1871 | if (UserBB == TruncUserBB) | |||
| 1872 | continue; | |||
| 1873 | ||||
| 1874 | BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB]; | |||
| 1875 | CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB]; | |||
| 1876 | ||||
| 1877 | if (!InsertedShift && !InsertedTrunc) { | |||
| 1878 | BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt(); | |||
| 1879 | assert(InsertPt != TruncUserBB->end())((void)0); | |||
| 1880 | // Sink the shift | |||
| 1881 | if (ShiftI->getOpcode() == Instruction::AShr) | |||
| 1882 | InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI, | |||
| 1883 | "", &*InsertPt); | |||
| 1884 | else | |||
| 1885 | InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI, | |||
| 1886 | "", &*InsertPt); | |||
| 1887 | InsertedShift->setDebugLoc(ShiftI->getDebugLoc()); | |||
| 1888 | ||||
| 1889 | // Sink the trunc | |||
| 1890 | BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt(); | |||
| 1891 | TruncInsertPt++; | |||
| 1892 | assert(TruncInsertPt != TruncUserBB->end())((void)0); | |||
| 1893 | ||||
| 1894 | InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift, | |||
| 1895 | TruncI->getType(), "", &*TruncInsertPt); | |||
| 1896 | InsertedTrunc->setDebugLoc(TruncI->getDebugLoc()); | |||
| 1897 | ||||
| 1898 | MadeChange = true; | |||
| 1899 | ||||
| 1900 | TruncTheUse = InsertedTrunc; | |||
| 1901 | } | |||
| 1902 | } | |||
| 1903 | return MadeChange; | |||
| 1904 | } | |||
| 1905 | ||||
| 1906 | /// Sink the shift *right* instruction into user blocks if the uses could | |||
| 1907 | /// potentially be combined with this shift instruction and generate BitExtract | |||
| 1908 | /// instruction. It will only be applied if the architecture supports BitExtract | |||
| 1909 | /// instruction. Here is an example: | |||
| 1910 | /// BB1: | |||
| 1911 | /// %x.extract.shift = lshr i64 %arg1, 32 | |||
| 1912 | /// BB2: | |||
| 1913 | /// %x.extract.trunc = trunc i64 %x.extract.shift to i16 | |||
| 1914 | /// ==> | |||
| 1915 | /// | |||
| 1916 | /// BB2: | |||
| 1917 | /// %x.extract.shift.1 = lshr i64 %arg1, 32 | |||
| 1918 | /// %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16 | |||
| 1919 | /// | |||
| 1920 | /// CodeGen will recognize the pattern in BB2 and generate BitExtract | |||
| 1921 | /// instruction. | |||
| 1922 | /// Return true if any changes are made. | |||
| 1923 | static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI, | |||
| 1924 | const TargetLowering &TLI, | |||
| 1925 | const DataLayout &DL) { | |||
| 1926 | BasicBlock *DefBB = ShiftI->getParent(); | |||
| 1927 | ||||
| 1928 | /// Only insert instructions in each block once. | |||
| 1929 | DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts; | |||
| 1930 | ||||
| 1931 | bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(DL, ShiftI->getType())); | |||
| 1932 | ||||
| 1933 | bool MadeChange = false; | |||
| 1934 | for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end(); | |||
| 1935 | UI != E;) { | |||
| 1936 | Use &TheUse = UI.getUse(); | |||
| 1937 | Instruction *User = cast<Instruction>(*UI); | |||
| 1938 | // Preincrement use iterator so we don't invalidate it. | |||
| 1939 | ++UI; | |||
| 1940 | ||||
| 1941 | // Don't bother for PHI nodes. | |||
| 1942 | if (isa<PHINode>(User)) | |||
| 1943 | continue; | |||
| 1944 | ||||
| 1945 | if (!isExtractBitsCandidateUse(User)) | |||
| 1946 | continue; | |||
| 1947 | ||||
| 1948 | BasicBlock *UserBB = User->getParent(); | |||
| 1949 | ||||
| 1950 | if (UserBB == DefBB) { | |||
| 1951 | // If the shift and truncate instruction are in the same BB. The use of | |||
| 1952 | // the truncate(TruncUse) may still introduce another truncate if not | |||
| 1953 | // legal. In this case, we would like to sink both shift and truncate | |||
| 1954 | // instruction to the BB of TruncUse. | |||
| 1955 | // for example: | |||
| 1956 | // BB1: | |||
| 1957 | // i64 shift.result = lshr i64 opnd, imm | |||
| 1958 | // trunc.result = trunc shift.result to i16 | |||
| 1959 | // | |||
| 1960 | // BB2: | |||
| 1961 | // ----> We will have an implicit truncate here if the architecture does | |||
| 1962 | // not have i16 compare. | |||
| 1963 | // cmp i16 trunc.result, opnd2 | |||
| 1964 | // | |||
| 1965 | if (isa<TruncInst>(User) && shiftIsLegal | |||
| 1966 | // If the type of the truncate is legal, no truncate will be | |||
| 1967 | // introduced in other basic blocks. | |||
| 1968 | && | |||
| 1969 | (!TLI.isTypeLegal(TLI.getValueType(DL, User->getType())))) | |||
| 1970 | MadeChange = | |||
| 1971 | SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI, DL); | |||
| 1972 | ||||
| 1973 | continue; | |||
| 1974 | } | |||
| 1975 | // If we have already inserted a shift into this block, use it. | |||
| 1976 | BinaryOperator *&InsertedShift = InsertedShifts[UserBB]; | |||
| 1977 | ||||
| 1978 | if (!InsertedShift) { | |||
| 1979 | BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt(); | |||
| 1980 | assert(InsertPt != UserBB->end())((void)0); | |||
| 1981 | ||||
| 1982 | if (ShiftI->getOpcode() == Instruction::AShr) | |||
| 1983 | InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI, | |||
| 1984 | "", &*InsertPt); | |||
| 1985 | else | |||
| 1986 | InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI, | |||
| 1987 | "", &*InsertPt); | |||
| 1988 | InsertedShift->setDebugLoc(ShiftI->getDebugLoc()); | |||
| 1989 | ||||
| 1990 | MadeChange = true; | |||
| 1991 | } | |||
| 1992 | ||||
| 1993 | // Replace a use of the shift with a use of the new shift. | |||
| 1994 | TheUse = InsertedShift; | |||
| 1995 | } | |||
| 1996 | ||||
| 1997 | // If we removed all uses, or there are none, nuke the shift. | |||
| 1998 | if (ShiftI->use_empty()) { | |||
| 1999 | salvageDebugInfo(*ShiftI); | |||
| 2000 | ShiftI->eraseFromParent(); | |||
| 2001 | MadeChange = true; | |||
| 2002 | } | |||
| 2003 | ||||
| 2004 | return MadeChange; | |||
| 2005 | } | |||
| 2006 | ||||
| 2007 | /// If counting leading or trailing zeros is an expensive operation and a zero | |||
| 2008 | /// input is defined, add a check for zero to avoid calling the intrinsic. | |||
| 2009 | /// | |||
| 2010 | /// We want to transform: | |||
| 2011 | /// %z = call i64 @llvm.cttz.i64(i64 %A, i1 false) | |||
| 2012 | /// | |||
| 2013 | /// into: | |||
| 2014 | /// entry: | |||
| 2015 | /// %cmpz = icmp eq i64 %A, 0 | |||
| 2016 | /// br i1 %cmpz, label %cond.end, label %cond.false | |||
| 2017 | /// cond.false: | |||
| 2018 | /// %z = call i64 @llvm.cttz.i64(i64 %A, i1 true) | |||
| 2019 | /// br label %cond.end | |||
| 2020 | /// cond.end: | |||
| 2021 | /// %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ] | |||
| 2022 | /// | |||
| 2023 | /// If the transform is performed, return true and set ModifiedDT to true. | |||
| 2024 | static bool despeculateCountZeros(IntrinsicInst *CountZeros, | |||
| 2025 | const TargetLowering *TLI, | |||
| 2026 | const DataLayout *DL, | |||
| 2027 | bool &ModifiedDT) { | |||
| 2028 | // If a zero input is undefined, it doesn't make sense to despeculate that. | |||
| 2029 | if (match(CountZeros->getOperand(1), m_One())) | |||
| 2030 | return false; | |||
| 2031 | ||||
| 2032 | // If it's cheap to speculate, there's nothing to do. | |||
| 2033 | auto IntrinsicID = CountZeros->getIntrinsicID(); | |||
| 2034 | if ((IntrinsicID == Intrinsic::cttz && TLI->isCheapToSpeculateCttz()) || | |||
| 2035 | (IntrinsicID == Intrinsic::ctlz && TLI->isCheapToSpeculateCtlz())) | |||
| 2036 | return false; | |||
| 2037 | ||||
| 2038 | // Only handle legal scalar cases. Anything else requires too much work. | |||
| 2039 | Type *Ty = CountZeros->getType(); | |||
| 2040 | unsigned SizeInBits = Ty->getPrimitiveSizeInBits(); | |||
| 2041 | if (Ty->isVectorTy() || SizeInBits > DL->getLargestLegalIntTypeSizeInBits()) | |||
| 2042 | return false; | |||
| 2043 | ||||
| 2044 | // Bail if the value is never zero. | |||
| 2045 | if (llvm::isKnownNonZero(CountZeros->getOperand(0), *DL)) | |||
| 2046 | return false; | |||
| 2047 | ||||
| 2048 | // The intrinsic will be sunk behind a compare against zero and branch. | |||
| 2049 | BasicBlock *StartBlock = CountZeros->getParent(); | |||
| 2050 | BasicBlock *CallBlock = StartBlock->splitBasicBlock(CountZeros, "cond.false"); | |||
| 2051 | ||||
| 2052 | // Create another block after the count zero intrinsic. A PHI will be added | |||
| 2053 | // in this block to select the result of the intrinsic or the bit-width | |||
| 2054 | // constant if the input to the intrinsic is zero. | |||
| 2055 | BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros)); | |||
| 2056 | BasicBlock *EndBlock = CallBlock->splitBasicBlock(SplitPt, "cond.end"); | |||
| 2057 | ||||
| 2058 | // Set up a builder to create a compare, conditional branch, and PHI. | |||
| 2059 | IRBuilder<> Builder(CountZeros->getContext()); | |||
| 2060 | Builder.SetInsertPoint(StartBlock->getTerminator()); | |||
| 2061 | Builder.SetCurrentDebugLocation(CountZeros->getDebugLoc()); | |||
| 2062 | ||||
| 2063 | // Replace the unconditional branch that was created by the first split with | |||
| 2064 | // a compare against zero and a conditional branch. | |||
| 2065 | Value *Zero = Constant::getNullValue(Ty); | |||
| 2066 | Value *Cmp = Builder.CreateICmpEQ(CountZeros->getOperand(0), Zero, "cmpz"); | |||
| 2067 | Builder.CreateCondBr(Cmp, EndBlock, CallBlock); | |||
| 2068 | StartBlock->getTerminator()->eraseFromParent(); | |||
| 2069 | ||||
| 2070 | // Create a PHI in the end block to select either the output of the intrinsic | |||
| 2071 | // or the bit width of the operand. | |||
| 2072 | Builder.SetInsertPoint(&EndBlock->front()); | |||
| 2073 | PHINode *PN = Builder.CreatePHI(Ty, 2, "ctz"); | |||
| 2074 | CountZeros->replaceAllUsesWith(PN); | |||
| 2075 | Value *BitWidth = Builder.getInt(APInt(SizeInBits, SizeInBits)); | |||
| 2076 | PN->addIncoming(BitWidth, StartBlock); | |||
| 2077 | PN->addIncoming(CountZeros, CallBlock); | |||
| 2078 | ||||
| 2079 | // We are explicitly handling the zero case, so we can set the intrinsic's | |||
| 2080 | // undefined zero argument to 'true'. This will also prevent reprocessing the | |||
| 2081 | // intrinsic; we only despeculate when a zero input is defined. | |||
| 2082 | CountZeros->setArgOperand(1, Builder.getTrue()); | |||
| 2083 | ModifiedDT = true; | |||
| 2084 | return true; | |||
| 2085 | } | |||
| 2086 | ||||
| 2087 | bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool &ModifiedDT) { | |||
| 2088 | BasicBlock *BB = CI->getParent(); | |||
| 2089 | ||||
| 2090 | // Lower inline assembly if we can. | |||
| 2091 | // If we found an inline asm expession, and if the target knows how to | |||
| 2092 | // lower it to normal LLVM code, do so now. | |||
| 2093 | if (CI->isInlineAsm()) { | |||
| 2094 | if (TLI->ExpandInlineAsm(CI)) { | |||
| 2095 | // Avoid invalidating the iterator. | |||
| 2096 | CurInstIterator = BB->begin(); | |||
| 2097 | // Avoid processing instructions out of order, which could cause | |||
| 2098 | // reuse before a value is defined. | |||
| 2099 | SunkAddrs.clear(); | |||
| 2100 | return true; | |||
| 2101 | } | |||
| 2102 | // Sink address computing for memory operands into the block. | |||
| 2103 | if (optimizeInlineAsmInst(CI)) | |||
| 2104 | return true; | |||
| 2105 | } | |||
| 2106 | ||||
| 2107 | // Align the pointer arguments to this call if the target thinks it's a good | |||
| 2108 | // idea | |||
| 2109 | unsigned MinSize, PrefAlign; | |||
| 2110 | if (TLI->shouldAlignPointerArgs(CI, MinSize, PrefAlign)) { | |||
| 2111 | for (auto &Arg : CI->arg_operands()) { | |||
| 2112 | // We want to align both objects whose address is used directly and | |||
| 2113 | // objects whose address is used in casts and GEPs, though it only makes | |||
| 2114 | // sense for GEPs if the offset is a multiple of the desired alignment and | |||
| 2115 | // if size - offset meets the size threshold. | |||
| 2116 | if (!Arg->getType()->isPointerTy()) | |||
| 2117 | continue; | |||
| 2118 | APInt Offset(DL->getIndexSizeInBits( | |||
| 2119 | cast<PointerType>(Arg->getType())->getAddressSpace()), | |||
| 2120 | 0); | |||
| 2121 | Value *Val = Arg->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset); | |||
| 2122 | uint64_t Offset2 = Offset.getLimitedValue(); | |||
| 2123 | if ((Offset2 & (PrefAlign-1)) != 0) | |||
| 2124 | continue; | |||
| 2125 | AllocaInst *AI; | |||
| 2126 | if ((AI = dyn_cast<AllocaInst>(Val)) && AI->getAlignment() < PrefAlign && | |||
| 2127 | DL->getTypeAllocSize(AI->getAllocatedType()) >= MinSize + Offset2) | |||
| 2128 | AI->setAlignment(Align(PrefAlign)); | |||
| 2129 | // Global variables can only be aligned if they are defined in this | |||
| 2130 | // object (i.e. they are uniquely initialized in this object), and | |||
| 2131 | // over-aligning global variables that have an explicit section is | |||
| 2132 | // forbidden. | |||
| 2133 | GlobalVariable *GV; | |||
| 2134 | if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() && | |||
| 2135 | GV->getPointerAlignment(*DL) < PrefAlign && | |||
| 2136 | DL->getTypeAllocSize(GV->getValueType()) >= | |||
| 2137 | MinSize + Offset2) | |||
| 2138 | GV->setAlignment(MaybeAlign(PrefAlign)); | |||
| 2139 | } | |||
| 2140 | // If this is a memcpy (or similar) then we may be able to improve the | |||
| 2141 | // alignment | |||
| 2142 | if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) { | |||
| 2143 | Align DestAlign = getKnownAlignment(MI->getDest(), *DL); | |||
| 2144 | MaybeAlign MIDestAlign = MI->getDestAlign(); | |||
| 2145 | if (!MIDestAlign || DestAlign > *MIDestAlign) | |||
| 2146 | MI->setDestAlignment(DestAlign); | |||
| 2147 | if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { | |||
| 2148 | MaybeAlign MTISrcAlign = MTI->getSourceAlign(); | |||
| 2149 | Align SrcAlign = getKnownAlignment(MTI->getSource(), *DL); | |||
| 2150 | if (!MTISrcAlign || SrcAlign > *MTISrcAlign) | |||
| 2151 | MTI->setSourceAlignment(SrcAlign); | |||
| 2152 | } | |||
| 2153 | } | |||
| 2154 | } | |||
| 2155 | ||||
| 2156 | // If we have a cold call site, try to sink addressing computation into the | |||
| 2157 | // cold block. This interacts with our handling for loads and stores to | |||
| 2158 | // ensure that we can fold all uses of a potential addressing computation | |||
| 2159 | // into their uses. TODO: generalize this to work over profiling data | |||
| 2160 | if (CI->hasFnAttr(Attribute::Cold) && | |||
| 2161 | !OptSize && !llvm::shouldOptimizeForSize(BB, PSI, BFI.get())) | |||
| 2162 | for (auto &Arg : CI->arg_operands()) { | |||
| 2163 | if (!Arg->getType()->isPointerTy()) | |||
| 2164 | continue; | |||
| 2165 | unsigned AS = Arg->getType()->getPointerAddressSpace(); | |||
| 2166 | return optimizeMemoryInst(CI, Arg, Arg->getType(), AS); | |||
| 2167 | } | |||
| 2168 | ||||
| 2169 | IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI); | |||
| 2170 | if (II) { | |||
| 2171 | switch (II->getIntrinsicID()) { | |||
| 2172 | default: break; | |||
| 2173 | case Intrinsic::assume: | |||
| 2174 | llvm_unreachable("llvm.assume should have been removed already")__builtin_unreachable(); | |||
| 2175 | case Intrinsic::experimental_widenable_condition: { | |||
| 2176 | // Give up on future widening oppurtunties so that we can fold away dead | |||
| 2177 | // paths and merge blocks before going into block-local instruction | |||
| 2178 | // selection. | |||
| 2179 | if (II->use_empty()) { | |||
| 2180 | II->eraseFromParent(); | |||
| 2181 | return true; | |||
| 2182 | } | |||
| 2183 | Constant *RetVal = ConstantInt::getTrue(II->getContext()); | |||
| 2184 | resetIteratorIfInvalidatedWhileCalling(BB, [&]() { | |||
| 2185 | replaceAndRecursivelySimplify(CI, RetVal, TLInfo, nullptr); | |||
| 2186 | }); | |||
| 2187 | return true; | |||
| 2188 | } | |||
| 2189 | case Intrinsic::objectsize: | |||
| 2190 | llvm_unreachable("llvm.objectsize.* should have been lowered already")__builtin_unreachable(); | |||
| 2191 | case Intrinsic::is_constant: | |||
| 2192 | llvm_unreachable("llvm.is.constant.* should have been lowered already")__builtin_unreachable(); | |||
| 2193 | case Intrinsic::aarch64_stlxr: | |||
| 2194 | case Intrinsic::aarch64_stxr: { | |||
| 2195 | ZExtInst *ExtVal = dyn_cast<ZExtInst>(CI->getArgOperand(0)); | |||
| 2196 | if (!ExtVal || !ExtVal->hasOneUse() || | |||
| 2197 | ExtVal->getParent() == CI->getParent()) | |||
| 2198 | return false; | |||
| 2199 | // Sink a zext feeding stlxr/stxr before it, so it can be folded into it. | |||
| 2200 | ExtVal->moveBefore(CI); | |||
| 2201 | // Mark this instruction as "inserted by CGP", so that other | |||
| 2202 | // optimizations don't touch it. | |||
| 2203 | InsertedInsts.insert(ExtVal); | |||
| 2204 | return true; | |||
| 2205 | } | |||
| 2206 | ||||
| 2207 | case Intrinsic::launder_invariant_group: | |||
| 2208 | case Intrinsic::strip_invariant_group: { | |||
| 2209 | Value *ArgVal = II->getArgOperand(0); | |||
| 2210 | auto it = LargeOffsetGEPMap.find(II); | |||
| 2211 | if (it != LargeOffsetGEPMap.end()) { | |||
| 2212 | // Merge entries in LargeOffsetGEPMap to reflect the RAUW. | |||
| 2213 | // Make sure not to have to deal with iterator invalidation | |||
| 2214 | // after possibly adding ArgVal to LargeOffsetGEPMap. | |||
| 2215 | auto GEPs = std::move(it->second); | |||
| 2216 | LargeOffsetGEPMap[ArgVal].append(GEPs.begin(), GEPs.end()); | |||
| 2217 | LargeOffsetGEPMap.erase(II); | |||
| 2218 | } | |||
| 2219 | ||||
| 2220 | II->replaceAllUsesWith(ArgVal); | |||
| 2221 | II->eraseFromParent(); | |||
| 2222 | return true; | |||
| 2223 | } | |||
| 2224 | case Intrinsic::cttz: | |||
| 2225 | case Intrinsic::ctlz: | |||
| 2226 | // If counting zeros is expensive, try to avoid it. | |||
| 2227 | return despeculateCountZeros(II, TLI, DL, ModifiedDT); | |||
| 2228 | case Intrinsic::fshl: | |||
| 2229 | case Intrinsic::fshr: | |||
| 2230 | return optimizeFunnelShift(II); | |||
| 2231 | case Intrinsic::dbg_value: | |||
| 2232 | return fixupDbgValue(II); | |||
| 2233 | case Intrinsic::vscale: { | |||
| 2234 | // If datalayout has no special restrictions on vector data layout, | |||
| 2235 | // replace `llvm.vscale` by an equivalent constant expression | |||
| 2236 | // to benefit from cheap constant propagation. | |||
| 2237 | Type *ScalableVectorTy = | |||
| 2238 | VectorType::get(Type::getInt8Ty(II->getContext()), 1, true); | |||
| 2239 | if (DL->getTypeAllocSize(ScalableVectorTy).getKnownMinSize() == 8) { | |||
| 2240 | auto *Null = Constant::getNullValue(ScalableVectorTy->getPointerTo()); | |||
| 2241 | auto *One = ConstantInt::getSigned(II->getType(), 1); | |||
| 2242 | auto *CGep = | |||
| 2243 | ConstantExpr::getGetElementPtr(ScalableVectorTy, Null, One); | |||
| 2244 | II->replaceAllUsesWith(ConstantExpr::getPtrToInt(CGep, II->getType())); | |||
| 2245 | II->eraseFromParent(); | |||
| 2246 | return true; | |||
| 2247 | } | |||
| 2248 | break; | |||
| 2249 | } | |||
| 2250 | case Intrinsic::masked_gather: | |||
| 2251 | return optimizeGatherScatterInst(II, II->getArgOperand(0)); | |||
| 2252 | case Intrinsic::masked_scatter: | |||
| 2253 | return optimizeGatherScatterInst(II, II->getArgOperand(1)); | |||
| 2254 | } | |||
| 2255 | ||||
| 2256 | SmallVector<Value *, 2> PtrOps; | |||
| 2257 | Type *AccessTy; | |||
| 2258 | if (TLI->getAddrModeArguments(II, PtrOps, AccessTy)) | |||
| 2259 | while (!PtrOps.empty()) { | |||
| 2260 | Value *PtrVal = PtrOps.pop_back_val(); | |||
| 2261 | unsigned AS = PtrVal->getType()->getPointerAddressSpace(); | |||
| 2262 | if (optimizeMemoryInst(II, PtrVal, AccessTy, AS)) | |||
| 2263 | return true; | |||
| 2264 | } | |||
| 2265 | } | |||
| 2266 | ||||
| 2267 | // From here on out we're working with named functions. | |||
| 2268 | if (!CI->getCalledFunction()) return false; | |||
| 2269 | ||||
| 2270 | // Lower all default uses of _chk calls. This is very similar | |||
| 2271 | // to what InstCombineCalls does, but here we are only lowering calls | |||
| 2272 | // to fortified library functions (e.g. __memcpy_chk) that have the default | |||
| 2273 | // "don't know" as the objectsize. Anything else should be left alone. | |||
| 2274 | FortifiedLibCallSimplifier Simplifier(TLInfo, true); | |||
| 2275 | IRBuilder<> Builder(CI); | |||
| 2276 | if (Value *V = Simplifier.optimizeCall(CI, Builder)) { | |||
| 2277 | CI->replaceAllUsesWith(V); | |||
| 2278 | CI->eraseFromParent(); | |||
| 2279 | return true; | |||
| 2280 | } | |||
| 2281 | ||||
| 2282 | return false; | |||
| 2283 | } | |||
| 2284 | ||||
| 2285 | /// Look for opportunities to duplicate return instructions to the predecessor | |||
| 2286 | /// to enable tail call optimizations. The case it is currently looking for is: | |||
| 2287 | /// @code | |||
| 2288 | /// bb0: | |||
| 2289 | /// %tmp0 = tail call i32 @f0() | |||
| 2290 | /// br label %return | |||
| 2291 | /// bb1: | |||
| 2292 | /// %tmp1 = tail call i32 @f1() | |||
| 2293 | /// br label %return | |||
| 2294 | /// bb2: | |||
| 2295 | /// %tmp2 = tail call i32 @f2() | |||
| 2296 | /// br label %return | |||
| 2297 | /// return: | |||
| 2298 | /// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ] | |||
| 2299 | /// ret i32 %retval | |||
| 2300 | /// @endcode | |||
| 2301 | /// | |||
| 2302 | /// => | |||
| 2303 | /// | |||
| 2304 | /// @code | |||
| 2305 | /// bb0: | |||
| 2306 | /// %tmp0 = tail call i32 @f0() | |||
| 2307 | /// ret i32 %tmp0 | |||
| 2308 | /// bb1: | |||
| 2309 | /// %tmp1 = tail call i32 @f1() | |||
| 2310 | /// ret i32 %tmp1 | |||
| 2311 | /// bb2: | |||
| 2312 | /// %tmp2 = tail call i32 @f2() | |||
| 2313 | /// ret i32 %tmp2 | |||
| 2314 | /// @endcode | |||
| 2315 | bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB, bool &ModifiedDT) { | |||
| 2316 | ReturnInst *RetI = dyn_cast<ReturnInst>(BB->getTerminator()); | |||
| 2317 | if (!RetI) | |||
| 2318 | return false; | |||
| 2319 | ||||
| 2320 | PHINode *PN = nullptr; | |||
| 2321 | ExtractValueInst *EVI = nullptr; | |||
| 2322 | BitCastInst *BCI = nullptr; | |||
| 2323 | Value *V = RetI->getReturnValue(); | |||
| 2324 | if (V) { | |||
| 2325 | BCI = dyn_cast<BitCastInst>(V); | |||
| 2326 | if (BCI) | |||
| 2327 | V = BCI->getOperand(0); | |||
| 2328 | ||||
| 2329 | EVI = dyn_cast<ExtractValueInst>(V); | |||
| 2330 | if (EVI) { | |||
| 2331 | V = EVI->getOperand(0); | |||
| 2332 | if (!llvm::all_of(EVI->indices(), [](unsigned idx) { return idx == 0; })) | |||
| 2333 | return false; | |||
| 2334 | } | |||
| 2335 | ||||
| 2336 | PN = dyn_cast<PHINode>(V); | |||
| 2337 | if (!PN) | |||
| 2338 | return false; | |||
| 2339 | } | |||
| 2340 | ||||
| 2341 | if (PN && PN->getParent() != BB) | |||
| 2342 | return false; | |||
| 2343 | ||||
| 2344 | auto isLifetimeEndOrBitCastFor = [](const Instruction *Inst) { | |||
| 2345 | const BitCastInst *BC = dyn_cast<BitCastInst>(Inst); | |||
| 2346 | if (BC && BC->hasOneUse()) | |||
| 2347 | Inst = BC->user_back(); | |||
| 2348 | ||||
| 2349 | if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) | |||
| 2350 | return II->getIntrinsicID() == Intrinsic::lifetime_end; | |||
| 2351 | return false; | |||
| 2352 | }; | |||
| 2353 | ||||
| 2354 | // Make sure there are no instructions between the first instruction | |||
| 2355 | // and return. | |||
| 2356 | const Instruction *BI = BB->getFirstNonPHI(); | |||
| 2357 | // Skip over debug and the bitcast. | |||
| 2358 | while (isa<DbgInfoIntrinsic>(BI) || BI == BCI || BI == EVI || | |||
| 2359 | isa<PseudoProbeInst>(BI) || isLifetimeEndOrBitCastFor(BI)) | |||
| 2360 | BI = BI->getNextNode(); | |||
| 2361 | if (BI != RetI) | |||
| 2362 | return false; | |||
| 2363 | ||||
| 2364 | /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail | |||
| 2365 | /// call. | |||
| 2366 | const Function *F = BB->getParent(); | |||
| 2367 | SmallVector<BasicBlock*, 4> TailCallBBs; | |||
| 2368 | if (PN) { | |||
| 2369 | for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) { | |||
| 2370 | // Look through bitcasts. | |||
| 2371 | Value *IncomingVal = PN->getIncomingValue(I)->stripPointerCasts(); | |||
| 2372 | CallInst *CI = dyn_cast<CallInst>(IncomingVal); | |||
| 2373 | BasicBlock *PredBB = PN->getIncomingBlock(I); | |||
| 2374 | // Make sure the phi value is indeed produced by the tail call. | |||
| 2375 | if (CI && CI->hasOneUse() && CI->getParent() == PredBB && | |||
| 2376 | TLI->mayBeEmittedAsTailCall(CI) && | |||
| 2377 | attributesPermitTailCall(F, CI, RetI, *TLI)) | |||
| 2378 | TailCallBBs.push_back(PredBB); | |||
| 2379 | } | |||
| 2380 | } else { | |||
| 2381 | SmallPtrSet<BasicBlock*, 4> VisitedBBs; | |||
| 2382 | for (BasicBlock *Pred : predecessors(BB)) { | |||
| 2383 | if (!VisitedBBs.insert(Pred).second) | |||
| 2384 | continue; | |||
| 2385 | if (Instruction *I = Pred->rbegin()->getPrevNonDebugInstruction(true)) { | |||
| 2386 | CallInst *CI = dyn_cast<CallInst>(I); | |||
| 2387 | if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) && | |||
| 2388 | attributesPermitTailCall(F, CI, RetI, *TLI)) | |||
| 2389 | TailCallBBs.push_back(Pred); | |||
| 2390 | } | |||
| 2391 | } | |||
| 2392 | } | |||
| 2393 | ||||
| 2394 | bool Changed = false; | |||
| 2395 | for (auto const &TailCallBB : TailCallBBs) { | |||
| 2396 | // Make sure the call instruction is followed by an unconditional branch to | |||
| 2397 | // the return block. | |||
| 2398 | BranchInst *BI = dyn_cast<BranchInst>(TailCallBB->getTerminator()); | |||
| 2399 | if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB) | |||
| 2400 | continue; | |||
| 2401 | ||||
| 2402 | // Duplicate the return into TailCallBB. | |||
| 2403 | (void)FoldReturnIntoUncondBranch(RetI, BB, TailCallBB); | |||
| 2404 | assert(!VerifyBFIUpdates ||((void)0) | |||
| 2405 | BFI->getBlockFreq(BB) >= BFI->getBlockFreq(TailCallBB))((void)0); | |||
| 2406 | BFI->setBlockFreq( | |||
| 2407 | BB, | |||
| 2408 | (BFI->getBlockFreq(BB) - BFI->getBlockFreq(TailCallBB)).getFrequency()); | |||
| 2409 | ModifiedDT = Changed = true; | |||
| 2410 | ++NumRetsDup; | |||
| 2411 | } | |||
| 2412 | ||||
| 2413 | // If we eliminated all predecessors of the block, delete the block now. | |||
| 2414 | if (Changed && !BB->hasAddressTaken() && pred_empty(BB)) | |||
| 2415 | BB->eraseFromParent(); | |||
| 2416 | ||||
| 2417 | return Changed; | |||
| 2418 | } | |||
| 2419 | ||||
| 2420 | //===----------------------------------------------------------------------===// | |||
| 2421 | // Memory Optimization | |||
| 2422 | //===----------------------------------------------------------------------===// | |||
| 2423 | ||||
| 2424 | namespace { | |||
| 2425 | ||||
| 2426 | /// This is an extended version of TargetLowering::AddrMode | |||
| 2427 | /// which holds actual Value*'s for register values. | |||
| 2428 | struct ExtAddrMode : public TargetLowering::AddrMode { | |||
| 2429 | Value *BaseReg = nullptr; | |||
| 2430 | Value *ScaledReg = nullptr; | |||
| 2431 | Value *OriginalValue = nullptr; | |||
| 2432 | bool InBounds = true; | |||
| 2433 | ||||
| 2434 | enum FieldName { | |||
| 2435 | NoField = 0x00, | |||
| 2436 | BaseRegField = 0x01, | |||
| 2437 | BaseGVField = 0x02, | |||
| 2438 | BaseOffsField = 0x04, | |||
| 2439 | ScaledRegField = 0x08, | |||
| 2440 | ScaleField = 0x10, | |||
| 2441 | MultipleFields = 0xff | |||
| 2442 | }; | |||
| 2443 | ||||
| 2444 | ||||
| 2445 | ExtAddrMode() = default; | |||
| 2446 | ||||
| 2447 | void print(raw_ostream &OS) const; | |||
| 2448 | void dump() const; | |||
| 2449 | ||||
| 2450 | FieldName compare(const ExtAddrMode &other) { | |||
| 2451 | // First check that the types are the same on each field, as differing types | |||
| 2452 | // is something we can't cope with later on. | |||
| 2453 | if (BaseReg && other.BaseReg && | |||
| 2454 | BaseReg->getType() != other.BaseReg->getType()) | |||
| 2455 | return MultipleFields; | |||
| 2456 | if (BaseGV && other.BaseGV && | |||
| 2457 | BaseGV->getType() != other.BaseGV->getType()) | |||
| 2458 | return MultipleFields; | |||
| 2459 | if (ScaledReg && other.ScaledReg && | |||
| 2460 | ScaledReg->getType() != other.ScaledReg->getType()) | |||
| 2461 | return MultipleFields; | |||
| 2462 | ||||
| 2463 | // Conservatively reject 'inbounds' mismatches. | |||
| 2464 | if (InBounds != other.InBounds) | |||
| 2465 | return MultipleFields; | |||
| 2466 | ||||
| 2467 | // Check each field to see if it differs. | |||
| 2468 | unsigned Result = NoField; | |||
| 2469 | if (BaseReg != other.BaseReg) | |||
| 2470 | Result |= BaseRegField; | |||
| 2471 | if (BaseGV != other.BaseGV) | |||
| 2472 | Result |= BaseGVField; | |||
| 2473 | if (BaseOffs != other.BaseOffs) | |||
| 2474 | Result |= BaseOffsField; | |||
| 2475 | if (ScaledReg != other.ScaledReg) | |||
| 2476 | Result |= ScaledRegField; | |||
| 2477 | // Don't count 0 as being a different scale, because that actually means | |||
| 2478 | // unscaled (which will already be counted by having no ScaledReg). | |||
| 2479 | if (Scale && other.Scale && Scale != other.Scale) | |||
| 2480 | Result |= ScaleField; | |||
| 2481 | ||||
| 2482 | if (countPopulation(Result) > 1) | |||
| 2483 | return MultipleFields; | |||
| 2484 | else | |||
| 2485 | return static_cast<FieldName>(Result); | |||
| 2486 | } | |||
| 2487 | ||||
| 2488 | // An AddrMode is trivial if it involves no calculation i.e. it is just a base | |||
| 2489 | // with no offset. | |||
| 2490 | bool isTrivial() { | |||
| 2491 | // An AddrMode is (BaseGV + BaseReg + BaseOffs + ScaleReg * Scale) so it is | |||
| 2492 | // trivial if at most one of these terms is nonzero, except that BaseGV and | |||
| 2493 | // BaseReg both being zero actually means a null pointer value, which we | |||
| 2494 | // consider to be 'non-zero' here. | |||
| 2495 | return !BaseOffs && !Scale && !(BaseGV && BaseReg); | |||
| 2496 | } | |||
| 2497 | ||||
| 2498 | Value *GetFieldAsValue(FieldName Field, Type *IntPtrTy) { | |||
| 2499 | switch (Field) { | |||
| 2500 | default: | |||
| 2501 | return nullptr; | |||
| 2502 | case BaseRegField: | |||
| 2503 | return BaseReg; | |||
| 2504 | case BaseGVField: | |||
| 2505 | return BaseGV; | |||
| 2506 | case ScaledRegField: | |||
| 2507 | return ScaledReg; | |||
| 2508 | case BaseOffsField: | |||
| 2509 | return ConstantInt::get(IntPtrTy, BaseOffs); | |||
| 2510 | } | |||
| 2511 | } | |||
| 2512 | ||||
| 2513 | void SetCombinedField(FieldName Field, Value *V, | |||
| 2514 | const SmallVectorImpl<ExtAddrMode> &AddrModes) { | |||
| 2515 | switch (Field) { | |||
| 2516 | default: | |||
| 2517 | llvm_unreachable("Unhandled fields are expected to be rejected earlier")__builtin_unreachable(); | |||
| 2518 | break; | |||
| 2519 | case ExtAddrMode::BaseRegField: | |||
| 2520 | BaseReg = V; | |||
| 2521 | break; | |||
| 2522 | case ExtAddrMode::BaseGVField: | |||
| 2523 | // A combined BaseGV is an Instruction, not a GlobalValue, so it goes | |||
| 2524 | // in the BaseReg field. | |||
| 2525 | assert(BaseReg == nullptr)((void)0); | |||
| 2526 | BaseReg = V; | |||
| 2527 | BaseGV = nullptr; | |||
| 2528 | break; | |||
| 2529 | case ExtAddrMode::ScaledRegField: | |||
| 2530 | ScaledReg = V; | |||
| 2531 | // If we have a mix of scaled and unscaled addrmodes then we want scale | |||
| 2532 | // to be the scale and not zero. | |||
| 2533 | if (!Scale) | |||
| 2534 | for (const ExtAddrMode &AM : AddrModes) | |||
| 2535 | if (AM.Scale) { | |||
| 2536 | Scale = AM.Scale; | |||
| 2537 | break; | |||
| 2538 | } | |||
| 2539 | break; | |||
| 2540 | case ExtAddrMode::BaseOffsField: | |||
| 2541 | // The offset is no longer a constant, so it goes in ScaledReg with a | |||
| 2542 | // scale of 1. | |||
| 2543 | assert(ScaledReg == nullptr)((void)0); | |||
| 2544 | ScaledReg = V; | |||
| 2545 | Scale = 1; | |||
| 2546 | BaseOffs = 0; | |||
| 2547 | break; | |||
| 2548 | } | |||
| 2549 | } | |||
| 2550 | }; | |||
| 2551 | ||||
| 2552 | } // end anonymous namespace | |||
| 2553 | ||||
| 2554 | #ifndef NDEBUG1 | |||
| 2555 | static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) { | |||
| 2556 | AM.print(OS); | |||
| 2557 | return OS; | |||
| 2558 | } | |||
| 2559 | #endif | |||
| 2560 | ||||
| 2561 | #if !defined(NDEBUG1) || defined(LLVM_ENABLE_DUMP) | |||
| 2562 | void ExtAddrMode::print(raw_ostream &OS) const { | |||
| 2563 | bool NeedPlus = false; | |||
| 2564 | OS << "["; | |||
| 2565 | if (InBounds) | |||
| 2566 | OS << "inbounds "; | |||
| 2567 | if (BaseGV) { | |||
| 2568 | OS << (NeedPlus ? " + " : "") | |||
| 2569 | << "GV:"; | |||
| 2570 | BaseGV->printAsOperand(OS, /*PrintType=*/false); | |||
| 2571 | NeedPlus = true; | |||
| 2572 | } | |||
| 2573 | ||||
| 2574 | if (BaseOffs) { | |||
| 2575 | OS << (NeedPlus ? " + " : "") | |||
| 2576 | << BaseOffs; | |||
| 2577 | NeedPlus = true; | |||
| 2578 | } | |||
| 2579 | ||||
| 2580 | if (BaseReg) { | |||
| 2581 | OS << (NeedPlus ? " + " : "") | |||
| 2582 | << "Base:"; | |||
| 2583 | BaseReg->printAsOperand(OS, /*PrintType=*/false); | |||
| 2584 | NeedPlus = true; | |||
| 2585 | } | |||
| 2586 | if (Scale) { | |||
| 2587 | OS << (NeedPlus ? " + " : "") | |||
| 2588 | << Scale << "*"; | |||
| 2589 | ScaledReg->printAsOperand(OS, /*PrintType=*/false); | |||
| 2590 | } | |||
| 2591 | ||||
| 2592 | OS << ']'; | |||
| 2593 | } | |||
| 2594 | ||||
| 2595 | LLVM_DUMP_METHOD__attribute__((noinline)) void ExtAddrMode::dump() const { | |||
| 2596 | print(dbgs()); | |||
| 2597 | dbgs() << '\n'; | |||
| 2598 | } | |||
| 2599 | #endif | |||
| 2600 | ||||
| 2601 | namespace { | |||
| 2602 | ||||
| 2603 | /// This class provides transaction based operation on the IR. | |||
| 2604 | /// Every change made through this class is recorded in the internal state and | |||
| 2605 | /// can be undone (rollback) until commit is called. | |||
| 2606 | /// CGP does not check if instructions could be speculatively executed when | |||
| 2607 | /// moved. Preserving the original location would pessimize the debugging | |||
| 2608 | /// experience, as well as negatively impact the quality of sample PGO. | |||
| 2609 | class TypePromotionTransaction { | |||
| 2610 | /// This represents the common interface of the individual transaction. | |||
| 2611 | /// Each class implements the logic for doing one specific modification on | |||
| 2612 | /// the IR via the TypePromotionTransaction. | |||
| 2613 | class TypePromotionAction { | |||
| 2614 | protected: | |||
| 2615 | /// The Instruction modified. | |||
| 2616 | Instruction *Inst; | |||
| 2617 | ||||
| 2618 | public: | |||
| 2619 | /// Constructor of the action. | |||
| 2620 | /// The constructor performs the related action on the IR. | |||
| 2621 | TypePromotionAction(Instruction *Inst) : Inst(Inst) {} | |||
| 2622 | ||||
| 2623 | virtual ~TypePromotionAction() = default; | |||
| 2624 | ||||
| 2625 | /// Undo the modification done by this action. | |||
| 2626 | /// When this method is called, the IR must be in the same state as it was | |||
| 2627 | /// before this action was applied. | |||
| 2628 | /// \pre Undoing the action works if and only if the IR is in the exact same | |||
| 2629 | /// state as it was directly after this action was applied. | |||
| 2630 | virtual void undo() = 0; | |||
| 2631 | ||||
| 2632 | /// Advocate every change made by this action. | |||
| 2633 | /// When the results on the IR of the action are to be kept, it is important | |||
| 2634 | /// to call this function, otherwise hidden information may be kept forever. | |||
| 2635 | virtual void commit() { | |||
| 2636 | // Nothing to be done, this action is not doing anything. | |||
| 2637 | } | |||
| 2638 | }; | |||
| 2639 | ||||
| 2640 | /// Utility to remember the position of an instruction. | |||
| 2641 | class InsertionHandler { | |||
| 2642 | /// Position of an instruction. | |||
| 2643 | /// Either an instruction: | |||
| 2644 | /// - Is the first in a basic block: BB is used. | |||
| 2645 | /// - Has a previous instruction: PrevInst is used. | |||
| 2646 | union { | |||
| 2647 | Instruction *PrevInst; | |||
| 2648 | BasicBlock *BB; | |||
| 2649 | } Point; | |||
| 2650 | ||||
| 2651 | /// Remember whether or not the instruction had a previous instruction. | |||
| 2652 | bool HasPrevInstruction; | |||
| 2653 | ||||
| 2654 | public: | |||
| 2655 | /// Record the position of \p Inst. | |||
| 2656 | InsertionHandler(Instruction *Inst) { | |||
| 2657 | BasicBlock::iterator It = Inst->getIterator(); | |||
| 2658 | HasPrevInstruction = (It != (Inst->getParent()->begin())); | |||
| 2659 | if (HasPrevInstruction) | |||
| 2660 | Point.PrevInst = &*--It; | |||
| 2661 | else | |||
| 2662 | Point.BB = Inst->getParent(); | |||
| 2663 | } | |||
| 2664 | ||||
| 2665 | /// Insert \p Inst at the recorded position. | |||
| 2666 | void insert(Instruction *Inst) { | |||
| 2667 | if (HasPrevInstruction) { | |||
| 2668 | if (Inst->getParent()) | |||
| 2669 | Inst->removeFromParent(); | |||
| 2670 | Inst->insertAfter(Point.PrevInst); | |||
| 2671 | } else { | |||
| 2672 | Instruction *Position = &*Point.BB->getFirstInsertionPt(); | |||
| 2673 | if (Inst->getParent()) | |||
| 2674 | Inst->moveBefore(Position); | |||
| 2675 | else | |||
| 2676 | Inst->insertBefore(Position); | |||
| 2677 | } | |||
| 2678 | } | |||
| 2679 | }; | |||
| 2680 | ||||
| 2681 | /// Move an instruction before another. | |||
| 2682 | class InstructionMoveBefore : public TypePromotionAction { | |||
| 2683 | /// Original position of the instruction. | |||
| 2684 | InsertionHandler Position; | |||
| 2685 | ||||
| 2686 | public: | |||
| 2687 | /// Move \p Inst before \p Before. | |||
| 2688 | InstructionMoveBefore(Instruction *Inst, Instruction *Before) | |||
| 2689 | : TypePromotionAction(Inst), Position(Inst) { | |||
| 2690 | LLVM_DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Beforedo { } while (false) | |||
| 2691 | << "\n")do { } while (false); | |||
| 2692 | Inst->moveBefore(Before); | |||
| 2693 | } | |||
| 2694 | ||||
| 2695 | /// Move the instruction back to its original position. | |||
| 2696 | void undo() override { | |||
| 2697 | LLVM_DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n")do { } while (false); | |||
| 2698 | Position.insert(Inst); | |||
| 2699 | } | |||
| 2700 | }; | |||
| 2701 | ||||
| 2702 | /// Set the operand of an instruction with a new value. | |||
| 2703 | class OperandSetter : public TypePromotionAction { | |||
| 2704 | /// Original operand of the instruction. | |||
| 2705 | Value *Origin; | |||
| 2706 | ||||
| 2707 | /// Index of the modified instruction. | |||
| 2708 | unsigned Idx; | |||
| 2709 | ||||
| 2710 | public: | |||
| 2711 | /// Set \p Idx operand of \p Inst with \p NewVal. | |||
| 2712 | OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal) | |||
| 2713 | : TypePromotionAction(Inst), Idx(Idx) { | |||
| 2714 | LLVM_DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"do { } while (false) | |||
| 2715 | << "for:" << *Inst << "\n"do { } while (false) | |||
| 2716 | << "with:" << *NewVal << "\n")do { } while (false); | |||
| 2717 | Origin = Inst->getOperand(Idx); | |||
| 2718 | Inst->setOperand(Idx, NewVal); | |||
| 2719 | } | |||
| 2720 | ||||
| 2721 | /// Restore the original value of the instruction. | |||
| 2722 | void undo() override { | |||
| 2723 | LLVM_DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"do { } while (false) | |||
| 2724 | << "for: " << *Inst << "\n"do { } while (false) | |||
| 2725 | << "with: " << *Origin << "\n")do { } while (false); | |||
| 2726 | Inst->setOperand(Idx, Origin); | |||
| 2727 | } | |||
| 2728 | }; | |||
| 2729 | ||||
| 2730 | /// Hide the operands of an instruction. | |||
| 2731 | /// Do as if this instruction was not using any of its operands. | |||
| 2732 | class OperandsHider : public TypePromotionAction { | |||
| 2733 | /// The list of original operands. | |||
| 2734 | SmallVector<Value *, 4> OriginalValues; | |||
| 2735 | ||||
| 2736 | public: | |||
| 2737 | /// Remove \p Inst from the uses of the operands of \p Inst. | |||
| 2738 | OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) { | |||
| 2739 | LLVM_DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n")do { } while (false); | |||
| 2740 | unsigned NumOpnds = Inst->getNumOperands(); | |||
| 2741 | OriginalValues.reserve(NumOpnds); | |||
| 2742 | for (unsigned It = 0; It < NumOpnds; ++It) { | |||
| 2743 | // Save the current operand. | |||
| 2744 | Value *Val = Inst->getOperand(It); | |||
| 2745 | OriginalValues.push_back(Val); | |||
| 2746 | // Set a dummy one. | |||
| 2747 | // We could use OperandSetter here, but that would imply an overhead | |||
| 2748 | // that we are not willing to pay. | |||
| 2749 | Inst->setOperand(It, UndefValue::get(Val->getType())); | |||
| 2750 | } | |||
| 2751 | } | |||
| 2752 | ||||
| 2753 | /// Restore the original list of uses. | |||
| 2754 | void undo() override { | |||
| 2755 | LLVM_DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n")do { } while (false); | |||
| 2756 | for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It) | |||
| 2757 | Inst->setOperand(It, OriginalValues[It]); | |||
| 2758 | } | |||
| 2759 | }; | |||
| 2760 | ||||
| 2761 | /// Build a truncate instruction. | |||
| 2762 | class TruncBuilder : public TypePromotionAction { | |||
| 2763 | Value *Val; | |||
| 2764 | ||||
| 2765 | public: | |||
| 2766 | /// Build a truncate instruction of \p Opnd producing a \p Ty | |||
| 2767 | /// result. | |||
| 2768 | /// trunc Opnd to Ty. | |||
| 2769 | TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) { | |||
| 2770 | IRBuilder<> Builder(Opnd); | |||
| 2771 | Builder.SetCurrentDebugLocation(DebugLoc()); | |||
| 2772 | Val = Builder.CreateTrunc(Opnd, Ty, "promoted"); | |||
| 2773 | LLVM_DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n")do { } while (false); | |||
| 2774 | } | |||
| 2775 | ||||
| 2776 | /// Get the built value. | |||
| 2777 | Value *getBuiltValue() { return Val; } | |||
| 2778 | ||||
| 2779 | /// Remove the built instruction. | |||
| 2780 | void undo() override { | |||
| 2781 | LLVM_DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n")do { } while (false); | |||
| 2782 | if (Instruction *IVal = dyn_cast<Instruction>(Val)) | |||
| 2783 | IVal->eraseFromParent(); | |||
| 2784 | } | |||
| 2785 | }; | |||
| 2786 | ||||
| 2787 | /// Build a sign extension instruction. | |||
| 2788 | class SExtBuilder : public TypePromotionAction { | |||
| 2789 | Value *Val; | |||
| 2790 | ||||
| 2791 | public: | |||
| 2792 | /// Build a sign extension instruction of \p Opnd producing a \p Ty | |||
| 2793 | /// result. | |||
| 2794 | /// sext Opnd to Ty. | |||
| 2795 | SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty) | |||
| 2796 | : TypePromotionAction(InsertPt) { | |||
| 2797 | IRBuilder<> Builder(InsertPt); | |||
| 2798 | Val = Builder.CreateSExt(Opnd, Ty, "promoted"); | |||
| 2799 | LLVM_DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n")do { } while (false); | |||
| 2800 | } | |||
| 2801 | ||||
| 2802 | /// Get the built value. | |||
| 2803 | Value *getBuiltValue() { return Val; } | |||
| 2804 | ||||
| 2805 | /// Remove the built instruction. | |||
| 2806 | void undo() override { | |||
| 2807 | LLVM_DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n")do { } while (false); | |||
| 2808 | if (Instruction *IVal = dyn_cast<Instruction>(Val)) | |||
| 2809 | IVal->eraseFromParent(); | |||
| 2810 | } | |||
| 2811 | }; | |||
| 2812 | ||||
| 2813 | /// Build a zero extension instruction. | |||
| 2814 | class ZExtBuilder : public TypePromotionAction { | |||
| 2815 | Value *Val; | |||
| 2816 | ||||
| 2817 | public: | |||
| 2818 | /// Build a zero extension instruction of \p Opnd producing a \p Ty | |||
| 2819 | /// result. | |||
| 2820 | /// zext Opnd to Ty. | |||
| 2821 | ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty) | |||
| 2822 | : TypePromotionAction(InsertPt) { | |||
| 2823 | IRBuilder<> Builder(InsertPt); | |||
| 2824 | Builder.SetCurrentDebugLocation(DebugLoc()); | |||
| 2825 | Val = Builder.CreateZExt(Opnd, Ty, "promoted"); | |||
| 2826 | LLVM_DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n")do { } while (false); | |||
| 2827 | } | |||
| 2828 | ||||
| 2829 | /// Get the built value. | |||
| 2830 | Value *getBuiltValue() { return Val; } | |||
| 2831 | ||||
| 2832 | /// Remove the built instruction. | |||
| 2833 | void undo() override { | |||
| 2834 | LLVM_DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n")do { } while (false); | |||
| 2835 | if (Instruction *IVal = dyn_cast<Instruction>(Val)) | |||
| 2836 | IVal->eraseFromParent(); | |||
| 2837 | } | |||
| 2838 | }; | |||
| 2839 | ||||
| 2840 | /// Mutate an instruction to another type. | |||
| 2841 | class TypeMutator : public TypePromotionAction { | |||
| 2842 | /// Record the original type. | |||
| 2843 | Type *OrigTy; | |||
| 2844 | ||||
| 2845 | public: | |||
| 2846 | /// Mutate the type of \p Inst into \p NewTy. | |||
| 2847 | TypeMutator(Instruction *Inst, Type *NewTy) | |||
| 2848 | : TypePromotionAction(Inst), OrigTy(Inst->getType()) { | |||
| 2849 | LLVM_DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTydo { } while (false) | |||
| 2850 | << "\n")do { } while (false); | |||
| 2851 | Inst->mutateType(NewTy); | |||
| 2852 | } | |||
| 2853 | ||||
| 2854 | /// Mutate the instruction back to its original type. | |||
| 2855 | void undo() override { | |||
| 2856 | LLVM_DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTydo { } while (false) | |||
| 2857 | << "\n")do { } while (false); | |||
| 2858 | Inst->mutateType(OrigTy); | |||
| 2859 | } | |||
| 2860 | }; | |||
| 2861 | ||||
| 2862 | /// Replace the uses of an instruction by another instruction. | |||
| 2863 | class UsesReplacer : public TypePromotionAction { | |||
| 2864 | /// Helper structure to keep track of the replaced uses. | |||
| 2865 | struct InstructionAndIdx { | |||
| 2866 | /// The instruction using the instruction. | |||
| 2867 | Instruction *Inst; | |||
| 2868 | ||||
| 2869 | /// The index where this instruction is used for Inst. | |||
| 2870 | unsigned Idx; | |||
| 2871 | ||||
| 2872 | InstructionAndIdx(Instruction *Inst, unsigned Idx) | |||
| 2873 | : Inst(Inst), Idx(Idx) {} | |||
| 2874 | }; | |||
| 2875 | ||||
| 2876 | /// Keep track of the original uses (pair Instruction, Index). | |||
| 2877 | SmallVector<InstructionAndIdx, 4> OriginalUses; | |||
| 2878 | /// Keep track of the debug users. | |||
| 2879 | SmallVector<DbgValueInst *, 1> DbgValues; | |||
| 2880 | ||||
| 2881 | /// Keep track of the new value so that we can undo it by replacing | |||
| 2882 | /// instances of the new value with the original value. | |||
| 2883 | Value *New; | |||
| 2884 | ||||
| 2885 | using use_iterator = SmallVectorImpl<InstructionAndIdx>::iterator; | |||
| 2886 | ||||
| 2887 | public: | |||
| 2888 | /// Replace all the use of \p Inst by \p New. | |||
| 2889 | UsesReplacer(Instruction *Inst, Value *New) | |||
| 2890 | : TypePromotionAction(Inst), New(New) { | |||
| 2891 | LLVM_DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *Newdo { } while (false) | |||
| 2892 | << "\n")do { } while (false); | |||
| 2893 | // Record the original uses. | |||
| 2894 | for (Use &U : Inst->uses()) { | |||
| 2895 | Instruction *UserI = cast<Instruction>(U.getUser()); | |||
| 2896 | OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo())); | |||
| 2897 | } | |||
| 2898 | // Record the debug uses separately. They are not in the instruction's | |||
| 2899 | // use list, but they are replaced by RAUW. | |||
| 2900 | findDbgValues(DbgValues, Inst); | |||
| 2901 | ||||
| 2902 | // Now, we can replace the uses. | |||
| 2903 | Inst->replaceAllUsesWith(New); | |||
| 2904 | } | |||
| 2905 | ||||
| 2906 | /// Reassign the original uses of Inst to Inst. | |||
| 2907 | void undo() override { | |||
| 2908 | LLVM_DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n")do { } while (false); | |||
| 2909 | for (InstructionAndIdx &Use : OriginalUses) | |||
| 2910 | Use.Inst->setOperand(Use.Idx, Inst); | |||
| 2911 | // RAUW has replaced all original uses with references to the new value, | |||
| 2912 | // including the debug uses. Since we are undoing the replacements, | |||
| 2913 | // the original debug uses must also be reinstated to maintain the | |||
| 2914 | // correctness and utility of debug value instructions. | |||
| 2915 | for (auto *DVI : DbgValues) | |||
| 2916 | DVI->replaceVariableLocationOp(New, Inst); | |||
| 2917 | } | |||
| 2918 | }; | |||
| 2919 | ||||
| 2920 | /// Remove an instruction from the IR. | |||
| 2921 | class InstructionRemover : public TypePromotionAction { | |||
| 2922 | /// Original position of the instruction. | |||
| 2923 | InsertionHandler Inserter; | |||
| 2924 | ||||
| 2925 | /// Helper structure to hide all the link to the instruction. In other | |||
| 2926 | /// words, this helps to do as if the instruction was removed. | |||
| 2927 | OperandsHider Hider; | |||
| 2928 | ||||
| 2929 | /// Keep track of the uses replaced, if any. | |||
| 2930 | UsesReplacer *Replacer = nullptr; | |||
| 2931 | ||||
| 2932 | /// Keep track of instructions removed. | |||
| 2933 | SetOfInstrs &RemovedInsts; | |||
| 2934 | ||||
| 2935 | public: | |||
| 2936 | /// Remove all reference of \p Inst and optionally replace all its | |||
| 2937 | /// uses with New. | |||
| 2938 | /// \p RemovedInsts Keep track of the instructions removed by this Action. | |||
| 2939 | /// \pre If !Inst->use_empty(), then New != nullptr | |||
| 2940 | InstructionRemover(Instruction *Inst, SetOfInstrs &RemovedInsts, | |||
| 2941 | Value *New = nullptr) | |||
| 2942 | : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst), | |||
| 2943 | RemovedInsts(RemovedInsts) { | |||
| 2944 | if (New) | |||
| 2945 | Replacer = new UsesReplacer(Inst, New); | |||
| 2946 | LLVM_DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n")do { } while (false); | |||
| 2947 | RemovedInsts.insert(Inst); | |||
| 2948 | /// The instructions removed here will be freed after completing | |||
| 2949 | /// optimizeBlock() for all blocks as we need to keep track of the | |||
| 2950 | /// removed instructions during promotion. | |||
| 2951 | Inst->removeFromParent(); | |||
| 2952 | } | |||
| 2953 | ||||
| 2954 | ~InstructionRemover() override { delete Replacer; } | |||
| 2955 | ||||
| 2956 | /// Resurrect the instruction and reassign it to the proper uses if | |||
| 2957 | /// new value was provided when build this action. | |||
| 2958 | void undo() override { | |||
| 2959 | LLVM_DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n")do { } while (false); | |||
| 2960 | Inserter.insert(Inst); | |||
| 2961 | if (Replacer) | |||
| 2962 | Replacer->undo(); | |||
| 2963 | Hider.undo(); | |||
| 2964 | RemovedInsts.erase(Inst); | |||
| 2965 | } | |||
| 2966 | }; | |||
| 2967 | ||||
| 2968 | public: | |||
| 2969 | /// Restoration point. | |||
| 2970 | /// The restoration point is a pointer to an action instead of an iterator | |||
| 2971 | /// because the iterator may be invalidated but not the pointer. | |||
| 2972 | using ConstRestorationPt = const TypePromotionAction *; | |||
| 2973 | ||||
| 2974 | TypePromotionTransaction(SetOfInstrs &RemovedInsts) | |||
| 2975 | : RemovedInsts(RemovedInsts) {} | |||
| 2976 | ||||
| 2977 | /// Advocate every changes made in that transaction. Return true if any change | |||
| 2978 | /// happen. | |||
| 2979 | bool commit(); | |||
| 2980 | ||||
| 2981 | /// Undo all the changes made after the given point. | |||
| 2982 | void rollback(ConstRestorationPt Point); | |||
| 2983 | ||||
| 2984 | /// Get the current restoration point. | |||
| 2985 | ConstRestorationPt getRestorationPoint() const; | |||
| 2986 | ||||
| 2987 | /// \name API for IR modification with state keeping to support rollback. | |||
| 2988 | /// @{ | |||
| 2989 | /// Same as Instruction::setOperand. | |||
| 2990 | void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal); | |||
| 2991 | ||||
| 2992 | /// Same as Instruction::eraseFromParent. | |||
| 2993 | void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr); | |||
| 2994 | ||||
| 2995 | /// Same as Value::replaceAllUsesWith. | |||
| 2996 | void replaceAllUsesWith(Instruction *Inst, Value *New); | |||
| 2997 | ||||
| 2998 | /// Same as Value::mutateType. | |||
| 2999 | void mutateType(Instruction *Inst, Type *NewTy); | |||
| 3000 | ||||
| 3001 | /// Same as IRBuilder::createTrunc. | |||
| 3002 | Value *createTrunc(Instruction *Opnd, Type *Ty); | |||
| 3003 | ||||
| 3004 | /// Same as IRBuilder::createSExt. | |||
| 3005 | Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty); | |||
| 3006 | ||||
| 3007 | /// Same as IRBuilder::createZExt. | |||
| 3008 | Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty); | |||
| 3009 | ||||
| 3010 | /// Same as Instruction::moveBefore. | |||
| 3011 | void moveBefore(Instruction *Inst, Instruction *Before); | |||
| 3012 | /// @} | |||
| 3013 | ||||
| 3014 | private: | |||
| 3015 | /// The ordered list of actions made so far. | |||
| 3016 | SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions; | |||
| 3017 | ||||
| 3018 | using CommitPt = SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator; | |||
| 3019 | ||||
| 3020 | SetOfInstrs &RemovedInsts; | |||
| 3021 | }; | |||
| 3022 | ||||
| 3023 | } // end anonymous namespace | |||
| 3024 | ||||
| 3025 | void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx, | |||
| 3026 | Value *NewVal) { | |||
| 3027 | Actions.push_back(std::make_unique<TypePromotionTransaction::OperandSetter>( | |||
| 3028 | Inst, Idx, NewVal)); | |||
| 3029 | } | |||
| 3030 | ||||
| 3031 | void TypePromotionTransaction::eraseInstruction(Instruction *Inst, | |||
| 3032 | Value *NewVal) { | |||
| 3033 | Actions.push_back( | |||
| 3034 | std::make_unique<TypePromotionTransaction::InstructionRemover>( | |||
| 3035 | Inst, RemovedInsts, NewVal)); | |||
| 3036 | } | |||
| 3037 | ||||
| 3038 | void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst, | |||
| 3039 | Value *New) { | |||
| 3040 | Actions.push_back( | |||
| 3041 | std::make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New)); | |||
| 3042 | } | |||
| 3043 | ||||
| 3044 | void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) { | |||
| 3045 | Actions.push_back( | |||
| 3046 | std::make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy)); | |||
| 3047 | } | |||
| 3048 | ||||
| 3049 | Value *TypePromotionTransaction::createTrunc(Instruction *Opnd, | |||
| 3050 | Type *Ty) { | |||
| 3051 | std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty)); | |||
| 3052 | Value *Val = Ptr->getBuiltValue(); | |||
| 3053 | Actions.push_back(std::move(Ptr)); | |||
| 3054 | return Val; | |||
| 3055 | } | |||
| 3056 | ||||
| 3057 | Value *TypePromotionTransaction::createSExt(Instruction *Inst, | |||
| 3058 | Value *Opnd, Type *Ty) { | |||
| 3059 | std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty)); | |||
| 3060 | Value *Val = Ptr->getBuiltValue(); | |||
| 3061 | Actions.push_back(std::move(Ptr)); | |||
| 3062 | return Val; | |||
| 3063 | } | |||
| 3064 | ||||
| 3065 | Value *TypePromotionTransaction::createZExt(Instruction *Inst, | |||
| 3066 | Value *Opnd, Type *Ty) { | |||
| 3067 | std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty)); | |||
| 3068 | Value *Val = Ptr->getBuiltValue(); | |||
| 3069 | Actions.push_back(std::move(Ptr)); | |||
| 3070 | return Val; | |||
| 3071 | } | |||
| 3072 | ||||
| 3073 | void TypePromotionTransaction::moveBefore(Instruction *Inst, | |||
| 3074 | Instruction *Before) { | |||
| 3075 | Actions.push_back( | |||
| 3076 | std::make_unique<TypePromotionTransaction::InstructionMoveBefore>( | |||
| 3077 | Inst, Before)); | |||
| 3078 | } | |||
| 3079 | ||||
| 3080 | TypePromotionTransaction::ConstRestorationPt | |||
| 3081 | TypePromotionTransaction::getRestorationPoint() const { | |||
| 3082 | return !Actions.empty() ? Actions.back().get() : nullptr; | |||
| 3083 | } | |||
| 3084 | ||||
| 3085 | bool TypePromotionTransaction::commit() { | |||
| 3086 | for (std::unique_ptr<TypePromotionAction> &Action : Actions) | |||
| 3087 | Action->commit(); | |||
| 3088 | bool Modified = !Actions.empty(); | |||
| 3089 | Actions.clear(); | |||
| 3090 | return Modified; | |||
| 3091 | } | |||
| 3092 | ||||
| 3093 | void TypePromotionTransaction::rollback( | |||
| 3094 | TypePromotionTransaction::ConstRestorationPt Point) { | |||
| 3095 | while (!Actions.empty() && Point != Actions.back().get()) { | |||
| 3096 | std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val(); | |||
| 3097 | Curr->undo(); | |||
| 3098 | } | |||
| 3099 | } | |||
| 3100 | ||||
| 3101 | namespace { | |||
| 3102 | ||||
| 3103 | /// A helper class for matching addressing modes. | |||
| 3104 | /// | |||
| 3105 | /// This encapsulates the logic for matching the target-legal addressing modes. | |||
| 3106 | class AddressingModeMatcher { | |||
| 3107 | SmallVectorImpl<Instruction*> &AddrModeInsts; | |||
| 3108 | const TargetLowering &TLI; | |||
| 3109 | const TargetRegisterInfo &TRI; | |||
| 3110 | const DataLayout &DL; | |||
| 3111 | const LoopInfo &LI; | |||
| 3112 | const std::function<const DominatorTree &()> getDTFn; | |||
| 3113 | ||||
| 3114 | /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and | |||
| 3115 | /// the memory instruction that we're computing this address for. | |||
| 3116 | Type *AccessTy; | |||
| 3117 | unsigned AddrSpace; | |||
| 3118 | Instruction *MemoryInst; | |||
| 3119 | ||||
| 3120 | /// This is the addressing mode that we're building up. This is | |||
| 3121 | /// part of the return value of this addressing mode matching stuff. | |||
| 3122 | ExtAddrMode &AddrMode; | |||
| 3123 | ||||
| 3124 | /// The instructions inserted by other CodeGenPrepare optimizations. | |||
| 3125 | const SetOfInstrs &InsertedInsts; | |||
| 3126 | ||||
| 3127 | /// A map from the instructions to their type before promotion. | |||
| 3128 | InstrToOrigTy &PromotedInsts; | |||
| 3129 | ||||
| 3130 | /// The ongoing transaction where every action should be registered. | |||
| 3131 | TypePromotionTransaction &TPT; | |||
| 3132 | ||||
| 3133 | // A GEP which has too large offset to be folded into the addressing mode. | |||
| 3134 | std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP; | |||
| 3135 | ||||
| 3136 | /// This is set to true when we should not do profitability checks. | |||
| 3137 | /// When true, IsProfitableToFoldIntoAddressingMode always returns true. | |||
| 3138 | bool IgnoreProfitability; | |||
| 3139 | ||||
| 3140 | /// True if we are optimizing for size. | |||
| 3141 | bool OptSize; | |||
| 3142 | ||||
| 3143 | ProfileSummaryInfo *PSI; | |||
| 3144 | BlockFrequencyInfo *BFI; | |||
| 3145 | ||||
| 3146 | AddressingModeMatcher( | |||
| 3147 | SmallVectorImpl<Instruction *> &AMI, const TargetLowering &TLI, | |||
| 3148 | const TargetRegisterInfo &TRI, const LoopInfo &LI, | |||
| 3149 | const std::function<const DominatorTree &()> getDTFn, | |||
| 3150 | Type *AT, unsigned AS, Instruction *MI, ExtAddrMode &AM, | |||
| 3151 | const SetOfInstrs &InsertedInsts, InstrToOrigTy &PromotedInsts, | |||
| 3152 | TypePromotionTransaction &TPT, | |||
| 3153 | std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP, | |||
| 3154 | bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) | |||
| 3155 | : AddrModeInsts(AMI), TLI(TLI), TRI(TRI), | |||
| 3156 | DL(MI->getModule()->getDataLayout()), LI(LI), getDTFn(getDTFn), | |||
| 3157 | AccessTy(AT), AddrSpace(AS), MemoryInst(MI), AddrMode(AM), | |||
| 3158 | InsertedInsts(InsertedInsts), PromotedInsts(PromotedInsts), TPT(TPT), | |||
| 3159 | LargeOffsetGEP(LargeOffsetGEP), OptSize(OptSize), PSI(PSI), BFI(BFI) { | |||
| 3160 | IgnoreProfitability = false; | |||
| 3161 | } | |||
| 3162 | ||||
| 3163 | public: | |||
| 3164 | /// Find the maximal addressing mode that a load/store of V can fold, | |||
| 3165 | /// give an access type of AccessTy. This returns a list of involved | |||
| 3166 | /// instructions in AddrModeInsts. | |||
| 3167 | /// \p InsertedInsts The instructions inserted by other CodeGenPrepare | |||
| 3168 | /// optimizations. | |||
| 3169 | /// \p PromotedInsts maps the instructions to their type before promotion. | |||
| 3170 | /// \p The ongoing transaction where every action should be registered. | |||
| 3171 | static ExtAddrMode | |||
| 3172 | Match(Value *V, Type *AccessTy, unsigned AS, Instruction *MemoryInst, | |||
| 3173 | SmallVectorImpl<Instruction *> &AddrModeInsts, | |||
| 3174 | const TargetLowering &TLI, const LoopInfo &LI, | |||
| 3175 | const std::function<const DominatorTree &()> getDTFn, | |||
| 3176 | const TargetRegisterInfo &TRI, const SetOfInstrs &InsertedInsts, | |||
| 3177 | InstrToOrigTy &PromotedInsts, TypePromotionTransaction &TPT, | |||
| 3178 | std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP, | |||
| 3179 | bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) { | |||
| 3180 | ExtAddrMode Result; | |||
| 3181 | ||||
| 3182 | bool Success = AddressingModeMatcher( | |||
| 3183 | AddrModeInsts, TLI, TRI, LI, getDTFn, AccessTy, AS, MemoryInst, Result, | |||
| 3184 | InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI, | |||
| 3185 | BFI).matchAddr(V, 0); | |||
| 3186 | (void)Success; assert(Success && "Couldn't select *anything*?")((void)0); | |||
| 3187 | return Result; | |||
| 3188 | } | |||
| 3189 | ||||
| 3190 | private: | |||
| 3191 | bool matchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth); | |||
| 3192 | bool matchAddr(Value *Addr, unsigned Depth); | |||
| 3193 | bool matchOperationAddr(User *AddrInst, unsigned Opcode, unsigned Depth, | |||
| 3194 | bool *MovedAway = nullptr); | |||
| 3195 | bool isProfitableToFoldIntoAddressingMode(Instruction *I, | |||
| 3196 | ExtAddrMode &AMBefore, | |||
| 3197 | ExtAddrMode &AMAfter); | |||
| 3198 | bool valueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2); | |||
| 3199 | bool isPromotionProfitable(unsigned NewCost, unsigned OldCost, | |||
| 3200 | Value *PromotedOperand) const; | |||
| 3201 | }; | |||
| 3202 | ||||
| 3203 | class PhiNodeSet; | |||
| 3204 | ||||
| 3205 | /// An iterator for PhiNodeSet. | |||
| 3206 | class PhiNodeSetIterator { | |||
| 3207 | PhiNodeSet * const Set; | |||
| 3208 | size_t CurrentIndex = 0; | |||
| 3209 | ||||
| 3210 | public: | |||
| 3211 | /// The constructor. Start should point to either a valid element, or be equal | |||
| 3212 | /// to the size of the underlying SmallVector of the PhiNodeSet. | |||
| 3213 | PhiNodeSetIterator(PhiNodeSet * const Set, size_t Start); | |||
| 3214 | PHINode * operator*() const; | |||
| 3215 | PhiNodeSetIterator& operator++(); | |||
| 3216 | bool operator==(const PhiNodeSetIterator &RHS) const; | |||
| 3217 | bool operator!=(const PhiNodeSetIterator &RHS) const; | |||
| 3218 | }; | |||
| 3219 | ||||
| 3220 | /// Keeps a set of PHINodes. | |||
| 3221 | /// | |||
| 3222 | /// This is a minimal set implementation for a specific use case: | |||
| 3223 | /// It is very fast when there are very few elements, but also provides good | |||
| 3224 | /// performance when there are many. It is similar to SmallPtrSet, but also | |||
| 3225 | /// provides iteration by insertion order, which is deterministic and stable | |||
| 3226 | /// across runs. It is also similar to SmallSetVector, but provides removing | |||
| 3227 | /// elements in O(1) time. This is achieved by not actually removing the element | |||
| 3228 | /// from the underlying vector, so comes at the cost of using more memory, but | |||
| 3229 | /// that is fine, since PhiNodeSets are used as short lived objects. | |||
| 3230 | class PhiNodeSet { | |||
| 3231 | friend class PhiNodeSetIterator; | |||
| 3232 | ||||
| 3233 | using MapType = SmallDenseMap<PHINode *, size_t, 32>; | |||
| 3234 | using iterator = PhiNodeSetIterator; | |||
| 3235 | ||||
| 3236 | /// Keeps the elements in the order of their insertion in the underlying | |||
| 3237 | /// vector. To achieve constant time removal, it never deletes any element. | |||
| 3238 | SmallVector<PHINode *, 32> NodeList; | |||
| 3239 | ||||
| 3240 | /// Keeps the elements in the underlying set implementation. This (and not the | |||
| 3241 | /// NodeList defined above) is the source of truth on whether an element | |||
| 3242 | /// is actually in the collection. | |||
| 3243 | MapType NodeMap; | |||
| 3244 | ||||
| 3245 | /// Points to the first valid (not deleted) element when the set is not empty | |||
| 3246 | /// and the value is not zero. Equals to the size of the underlying vector | |||
| 3247 | /// when the set is empty. When the value is 0, as in the beginning, the | |||
| 3248 | /// first element may or may not be valid. | |||
| 3249 | size_t FirstValidElement = 0; | |||
| 3250 | ||||
| 3251 | public: | |||
| 3252 | /// Inserts a new element to the collection. | |||
| 3253 | /// \returns true if the element is actually added, i.e. was not in the | |||
| 3254 | /// collection before the operation. | |||
| 3255 | bool insert(PHINode *Ptr) { | |||
| 3256 | if (NodeMap.insert(std::make_pair(Ptr, NodeList.size())).second) { | |||
| 3257 | NodeList.push_back(Ptr); | |||
| 3258 | return true; | |||
| 3259 | } | |||
| 3260 | return false; | |||
| 3261 | } | |||
| 3262 | ||||
| 3263 | /// Removes the element from the collection. | |||
| 3264 | /// \returns whether the element is actually removed, i.e. was in the | |||
| 3265 | /// collection before the operation. | |||
| 3266 | bool erase(PHINode *Ptr) { | |||
| 3267 | if (NodeMap.erase(Ptr)) { | |||
| 3268 | SkipRemovedElements(FirstValidElement); | |||
| 3269 | return true; | |||
| 3270 | } | |||
| 3271 | return false; | |||
| 3272 | } | |||
| 3273 | ||||
| 3274 | /// Removes all elements and clears the collection. | |||
| 3275 | void clear() { | |||
| 3276 | NodeMap.clear(); | |||
| 3277 | NodeList.clear(); | |||
| 3278 | FirstValidElement = 0; | |||
| 3279 | } | |||
| 3280 | ||||
| 3281 | /// \returns an iterator that will iterate the elements in the order of | |||
| 3282 | /// insertion. | |||
| 3283 | iterator begin() { | |||
| 3284 | if (FirstValidElement == 0) | |||
| 3285 | SkipRemovedElements(FirstValidElement); | |||
| 3286 | return PhiNodeSetIterator(this, FirstValidElement); | |||
| 3287 | } | |||
| 3288 | ||||
| 3289 | /// \returns an iterator that points to the end of the collection. | |||
| 3290 | iterator end() { return PhiNodeSetIterator(this, NodeList.size()); } | |||
| 3291 | ||||
| 3292 | /// Returns the number of elements in the collection. | |||
| 3293 | size_t size() const { | |||
| 3294 | return NodeMap.size(); | |||
| 3295 | } | |||
| 3296 | ||||
| 3297 | /// \returns 1 if the given element is in the collection, and 0 if otherwise. | |||
| 3298 | size_t count(PHINode *Ptr) const { | |||
| 3299 | return NodeMap.count(Ptr); | |||
| 3300 | } | |||
| 3301 | ||||
| 3302 | private: | |||
| 3303 | /// Updates the CurrentIndex so that it will point to a valid element. | |||
| 3304 | /// | |||
| 3305 | /// If the element of NodeList at CurrentIndex is valid, it does not | |||
| 3306 | /// change it. If there are no more valid elements, it updates CurrentIndex | |||
| 3307 | /// to point to the end of the NodeList. | |||
| 3308 | void SkipRemovedElements(size_t &CurrentIndex) { | |||
| 3309 | while (CurrentIndex < NodeList.size()) { | |||
| 3310 | auto it = NodeMap.find(NodeList[CurrentIndex]); | |||
| 3311 | // If the element has been deleted and added again later, NodeMap will | |||
| 3312 | // point to a different index, so CurrentIndex will still be invalid. | |||
| 3313 | if (it != NodeMap.end() && it->second == CurrentIndex) | |||
| 3314 | break; | |||
| 3315 | ++CurrentIndex; | |||
| 3316 | } | |||
| 3317 | } | |||
| 3318 | }; | |||
| 3319 | ||||
| 3320 | PhiNodeSetIterator::PhiNodeSetIterator(PhiNodeSet *const Set, size_t Start) | |||
| 3321 | : Set(Set), CurrentIndex(Start) {} | |||
| 3322 | ||||
| 3323 | PHINode * PhiNodeSetIterator::operator*() const { | |||
| 3324 | assert(CurrentIndex < Set->NodeList.size() &&((void)0) | |||
| 3325 | "PhiNodeSet access out of range")((void)0); | |||
| 3326 | return Set->NodeList[CurrentIndex]; | |||
| 3327 | } | |||
| 3328 | ||||
| 3329 | PhiNodeSetIterator& PhiNodeSetIterator::operator++() { | |||
| 3330 | assert(CurrentIndex < Set->NodeList.size() &&((void)0) | |||
| 3331 | "PhiNodeSet access out of range")((void)0); | |||
| 3332 | ++CurrentIndex; | |||
| 3333 | Set->SkipRemovedElements(CurrentIndex); | |||
| 3334 | return *this; | |||
| 3335 | } | |||
| 3336 | ||||
| 3337 | bool PhiNodeSetIterator::operator==(const PhiNodeSetIterator &RHS) const { | |||
| 3338 | return CurrentIndex == RHS.CurrentIndex; | |||
| 3339 | } | |||
| 3340 | ||||
| 3341 | bool PhiNodeSetIterator::operator!=(const PhiNodeSetIterator &RHS) const { | |||
| 3342 | return !((*this) == RHS); | |||
| 3343 | } | |||
| 3344 | ||||
| 3345 | /// Keep track of simplification of Phi nodes. | |||
| 3346 | /// Accept the set of all phi nodes and erase phi node from this set | |||
| 3347 | /// if it is simplified. | |||
| 3348 | class SimplificationTracker { | |||
| 3349 | DenseMap<Value *, Value *> Storage; | |||
| 3350 | const SimplifyQuery &SQ; | |||
| 3351 | // Tracks newly created Phi nodes. The elements are iterated by insertion | |||
| 3352 | // order. | |||
| 3353 | PhiNodeSet AllPhiNodes; | |||
| 3354 | // Tracks newly created Select nodes. | |||
| 3355 | SmallPtrSet<SelectInst *, 32> AllSelectNodes; | |||
| 3356 | ||||
| 3357 | public: | |||
| 3358 | SimplificationTracker(const SimplifyQuery &sq) | |||
| 3359 | : SQ(sq) {} | |||
| 3360 | ||||
| 3361 | Value *Get(Value *V) { | |||
| 3362 | do { | |||
| 3363 | auto SV = Storage.find(V); | |||
| 3364 | if (SV == Storage.end()) | |||
| 3365 | return V; | |||
| 3366 | V = SV->second; | |||
| 3367 | } while (true); | |||
| 3368 | } | |||
| 3369 | ||||
| 3370 | Value *Simplify(Value *Val) { | |||
| 3371 | SmallVector<Value *, 32> WorkList; | |||
| 3372 | SmallPtrSet<Value *, 32> Visited; | |||
| 3373 | WorkList.push_back(Val); | |||
| 3374 | while (!WorkList.empty()) { | |||
| 3375 | auto *P = WorkList.pop_back_val(); | |||
| 3376 | if (!Visited.insert(P).second) | |||
| 3377 | continue; | |||
| 3378 | if (auto *PI = dyn_cast<Instruction>(P)) | |||
| 3379 | if (Value *V = SimplifyInstruction(cast<Instruction>(PI), SQ)) { | |||
| 3380 | for (auto *U : PI->users()) | |||
| 3381 | WorkList.push_back(cast<Value>(U)); | |||
| 3382 | Put(PI, V); | |||
| 3383 | PI->replaceAllUsesWith(V); | |||
| 3384 | if (auto *PHI = dyn_cast<PHINode>(PI)) | |||
| 3385 | AllPhiNodes.erase(PHI); | |||
| 3386 | if (auto *Select = dyn_cast<SelectInst>(PI)) | |||
| 3387 | AllSelectNodes.erase(Select); | |||
| 3388 | PI->eraseFromParent(); | |||
| 3389 | } | |||
| 3390 | } | |||
| 3391 | return Get(Val); | |||
| 3392 | } | |||
| 3393 | ||||
| 3394 | void Put(Value *From, Value *To) { | |||
| 3395 | Storage.insert({ From, To }); | |||
| 3396 | } | |||
| 3397 | ||||
| 3398 | void ReplacePhi(PHINode *From, PHINode *To) { | |||
| 3399 | Value* OldReplacement = Get(From); | |||
| 3400 | while (OldReplacement != From) { | |||
| 3401 | From = To; | |||
| 3402 | To = dyn_cast<PHINode>(OldReplacement); | |||
| 3403 | OldReplacement = Get(From); | |||
| 3404 | } | |||
| 3405 | assert(To && Get(To) == To && "Replacement PHI node is already replaced.")((void)0); | |||
| 3406 | Put(From, To); | |||
| 3407 | From->replaceAllUsesWith(To); | |||
| 3408 | AllPhiNodes.erase(From); | |||
| 3409 | From->eraseFromParent(); | |||
| 3410 | } | |||
| 3411 | ||||
| 3412 | PhiNodeSet& newPhiNodes() { return AllPhiNodes; } | |||
| 3413 | ||||
| 3414 | void insertNewPhi(PHINode *PN) { AllPhiNodes.insert(PN); } | |||
| 3415 | ||||
| 3416 | void insertNewSelect(SelectInst *SI) { AllSelectNodes.insert(SI); } | |||
| 3417 | ||||
| 3418 | unsigned countNewPhiNodes() const { return AllPhiNodes.size(); } | |||
| 3419 | ||||
| 3420 | unsigned countNewSelectNodes() const { return AllSelectNodes.size(); } | |||
| 3421 | ||||
| 3422 | void destroyNewNodes(Type *CommonType) { | |||
| 3423 | // For safe erasing, replace the uses with dummy value first. | |||
| 3424 | auto *Dummy = UndefValue::get(CommonType); | |||
| 3425 | for (auto *I : AllPhiNodes) { | |||
| 3426 | I->replaceAllUsesWith(Dummy); | |||
| 3427 | I->eraseFromParent(); | |||
| 3428 | } | |||
| 3429 | AllPhiNodes.clear(); | |||
| 3430 | for (auto *I : AllSelectNodes) { | |||
| 3431 | I->replaceAllUsesWith(Dummy); | |||
| 3432 | I->eraseFromParent(); | |||
| 3433 | } | |||
| 3434 | AllSelectNodes.clear(); | |||
| 3435 | } | |||
| 3436 | }; | |||
| 3437 | ||||
| 3438 | /// A helper class for combining addressing modes. | |||
| 3439 | class AddressingModeCombiner { | |||
| 3440 | typedef DenseMap<Value *, Value *> FoldAddrToValueMapping; | |||
| 3441 | typedef std::pair<PHINode *, PHINode *> PHIPair; | |||
| 3442 | ||||
| 3443 | private: | |||
| 3444 | /// The addressing modes we've collected. | |||
| 3445 | SmallVector<ExtAddrMode, 16> AddrModes; | |||
| 3446 | ||||
| 3447 | /// The field in which the AddrModes differ, when we have more than one. | |||
| 3448 | ExtAddrMode::FieldName DifferentField = ExtAddrMode::NoField; | |||
| 3449 | ||||
| 3450 | /// Are the AddrModes that we have all just equal to their original values? | |||
| 3451 | bool AllAddrModesTrivial = true; | |||
| 3452 | ||||
| 3453 | /// Common Type for all different fields in addressing modes. | |||
| 3454 | Type *CommonType; | |||
| 3455 | ||||
| 3456 | /// SimplifyQuery for simplifyInstruction utility. | |||
| 3457 | const SimplifyQuery &SQ; | |||
| 3458 | ||||
| 3459 | /// Original Address. | |||
| 3460 | Value *Original; | |||
| 3461 | ||||
| 3462 | public: | |||
| 3463 | AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue) | |||
| 3464 | : CommonType(nullptr), SQ(_SQ), Original(OriginalValue) {} | |||
| 3465 | ||||
| 3466 | /// Get the combined AddrMode | |||
| 3467 | const ExtAddrMode &getAddrMode() const { | |||
| 3468 | return AddrModes[0]; | |||
| 3469 | } | |||
| 3470 | ||||
| 3471 | /// Add a new AddrMode if it's compatible with the AddrModes we already | |||
| 3472 | /// have. | |||
| 3473 | /// \return True iff we succeeded in doing so. | |||
| 3474 | bool addNewAddrMode(ExtAddrMode &NewAddrMode) { | |||
| 3475 | // Take note of if we have any non-trivial AddrModes, as we need to detect | |||
| 3476 | // when all AddrModes are trivial as then we would introduce a phi or select | |||
| 3477 | // which just duplicates what's already there. | |||
| 3478 | AllAddrModesTrivial = AllAddrModesTrivial && NewAddrMode.isTrivial(); | |||
| 3479 | ||||
| 3480 | // If this is the first addrmode then everything is fine. | |||
| 3481 | if (AddrModes.empty()) { | |||
| 3482 | AddrModes.emplace_back(NewAddrMode); | |||
| 3483 | return true; | |||
| 3484 | } | |||
| 3485 | ||||
| 3486 | // Figure out how different this is from the other address modes, which we | |||
| 3487 | // can do just by comparing against the first one given that we only care | |||
| 3488 | // about the cumulative difference. | |||
| 3489 | ExtAddrMode::FieldName ThisDifferentField = | |||
| 3490 | AddrModes[0].compare(NewAddrMode); | |||
| 3491 | if (DifferentField == ExtAddrMode::NoField) | |||
| 3492 | DifferentField = ThisDifferentField; | |||
| 3493 | else if (DifferentField != ThisDifferentField) | |||
| 3494 | DifferentField = ExtAddrMode::MultipleFields; | |||
| 3495 | ||||
| 3496 | // If NewAddrMode differs in more than one dimension we cannot handle it. | |||
| 3497 | bool CanHandle = DifferentField != ExtAddrMode::MultipleFields; | |||
| 3498 | ||||
| 3499 | // If Scale Field is different then we reject. | |||
| 3500 | CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField; | |||
| 3501 | ||||
| 3502 | // We also must reject the case when base offset is different and | |||
| 3503 | // scale reg is not null, we cannot handle this case due to merge of | |||
| 3504 | // different offsets will be used as ScaleReg. | |||
| 3505 | CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField || | |||
| 3506 | !NewAddrMode.ScaledReg); | |||
| 3507 | ||||
| 3508 | // We also must reject the case when GV is different and BaseReg installed | |||
| 3509 | // due to we want to use base reg as a merge of GV values. | |||
| 3510 | CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField || | |||
| 3511 | !NewAddrMode.HasBaseReg); | |||
| 3512 | ||||
| 3513 | // Even if NewAddMode is the same we still need to collect it due to | |||
| 3514 | // original value is different. And later we will need all original values | |||
| 3515 | // as anchors during finding the common Phi node. | |||
| 3516 | if (CanHandle) | |||
| 3517 | AddrModes.emplace_back(NewAddrMode); | |||
| 3518 | else | |||
| 3519 | AddrModes.clear(); | |||
| 3520 | ||||
| 3521 | return CanHandle; | |||
| 3522 | } | |||
| 3523 | ||||
| 3524 | /// Combine the addressing modes we've collected into a single | |||
| 3525 | /// addressing mode. | |||
| 3526 | /// \return True iff we successfully combined them or we only had one so | |||
| 3527 | /// didn't need to combine them anyway. | |||
| 3528 | bool combineAddrModes() { | |||
| 3529 | // If we have no AddrModes then they can't be combined. | |||
| 3530 | if (AddrModes.size() == 0) | |||
| 3531 | return false; | |||
| 3532 | ||||
| 3533 | // A single AddrMode can trivially be combined. | |||
| 3534 | if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField) | |||
| 3535 | return true; | |||
| 3536 | ||||
| 3537 | // If the AddrModes we collected are all just equal to the value they are | |||
| 3538 | // derived from then combining them wouldn't do anything useful. | |||
| 3539 | if (AllAddrModesTrivial) | |||
| 3540 | return false; | |||
| 3541 | ||||
| 3542 | if (!addrModeCombiningAllowed()) | |||
| 3543 | return false; | |||
| 3544 | ||||
| 3545 | // Build a map between <original value, basic block where we saw it> to | |||
| 3546 | // value of base register. | |||
| 3547 | // Bail out if there is no common type. | |||
| 3548 | FoldAddrToValueMapping Map; | |||
| 3549 | if (!initializeMap(Map)) | |||
| 3550 | return false; | |||
| 3551 | ||||
| 3552 | Value *CommonValue = findCommon(Map); | |||
| 3553 | if (CommonValue) | |||
| 3554 | AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes); | |||
| 3555 | return CommonValue != nullptr; | |||
| 3556 | } | |||
| 3557 | ||||
| 3558 | private: | |||
| 3559 | /// Initialize Map with anchor values. For address seen | |||
| 3560 | /// we set the value of different field saw in this address. | |||
| 3561 | /// At the same time we find a common type for different field we will | |||
| 3562 | /// use to create new Phi/Select nodes. Keep it in CommonType field. | |||
| 3563 | /// Return false if there is no common type found. | |||
| 3564 | bool initializeMap(FoldAddrToValueMapping &Map) { | |||
| 3565 | // Keep track of keys where the value is null. We will need to replace it | |||
| 3566 | // with constant null when we know the common type. | |||
| 3567 | SmallVector<Value *, 2> NullValue; | |||
| 3568 | Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType()); | |||
| 3569 | for (auto &AM : AddrModes) { | |||
| 3570 | Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy); | |||
| 3571 | if (DV) { | |||
| 3572 | auto *Type = DV->getType(); | |||
| 3573 | if (CommonType && CommonType != Type) | |||
| 3574 | return false; | |||
| 3575 | CommonType = Type; | |||
| 3576 | Map[AM.OriginalValue] = DV; | |||
| 3577 | } else { | |||
| 3578 | NullValue.push_back(AM.OriginalValue); | |||
| 3579 | } | |||
| 3580 | } | |||
| 3581 | assert(CommonType && "At least one non-null value must be!")((void)0); | |||
| 3582 | for (auto *V : NullValue) | |||
| 3583 | Map[V] = Constant::getNullValue(CommonType); | |||
| 3584 | return true; | |||
| 3585 | } | |||
| 3586 | ||||
| 3587 | /// We have mapping between value A and other value B where B was a field in | |||
| 3588 | /// addressing mode represented by A. Also we have an original value C | |||
| 3589 | /// representing an address we start with. Traversing from C through phi and | |||
| 3590 | /// selects we ended up with A's in a map. This utility function tries to find | |||
| 3591 | /// a value V which is a field in addressing mode C and traversing through phi | |||
| 3592 | /// nodes and selects we will end up in corresponded values B in a map. | |||
| 3593 | /// The utility will create a new Phi/Selects if needed. | |||
| 3594 | // The simple example looks as follows: | |||
| 3595 | // BB1: | |||
| 3596 | // p1 = b1 + 40 | |||
| 3597 | // br cond BB2, BB3 | |||
| 3598 | // BB2: | |||
| 3599 | // p2 = b2 + 40 | |||
| 3600 | // br BB3 | |||
| 3601 | // BB3: | |||
| 3602 | // p = phi [p1, BB1], [p2, BB2] | |||
| 3603 | // v = load p | |||
| 3604 | // Map is | |||
| 3605 | // p1 -> b1 | |||
| 3606 | // p2 -> b2 | |||
| 3607 | // Request is | |||
| 3608 | // p -> ? | |||
| 3609 | // The function tries to find or build phi [b1, BB1], [b2, BB2] in BB3. | |||
| 3610 | Value *findCommon(FoldAddrToValueMapping &Map) { | |||
| 3611 | // Tracks the simplification of newly created phi nodes. The reason we use | |||
| 3612 | // this mapping is because we will add new created Phi nodes in AddrToBase. | |||
| 3613 | // Simplification of Phi nodes is recursive, so some Phi node may | |||
| 3614 | // be simplified after we added it to AddrToBase. In reality this | |||
| 3615 | // simplification is possible only if original phi/selects were not | |||
| 3616 | // simplified yet. | |||
| 3617 | // Using this mapping we can find the current value in AddrToBase. | |||
| 3618 | SimplificationTracker ST(SQ); | |||
| 3619 | ||||
| 3620 | // First step, DFS to create PHI nodes for all intermediate blocks. | |||
| 3621 | // Also fill traverse order for the second step. | |||
| 3622 | SmallVector<Value *, 32> TraverseOrder; | |||
| 3623 | InsertPlaceholders(Map, TraverseOrder, ST); | |||
| 3624 | ||||
| 3625 | // Second Step, fill new nodes by merged values and simplify if possible. | |||
| 3626 | FillPlaceholders(Map, TraverseOrder, ST); | |||
| 3627 | ||||
| 3628 | if (!AddrSinkNewSelects && ST.countNewSelectNodes() > 0) { | |||
| 3629 | ST.destroyNewNodes(CommonType); | |||
| 3630 | return nullptr; | |||
| 3631 | } | |||
| 3632 | ||||
| 3633 | // Now we'd like to match New Phi nodes to existed ones. | |||
| 3634 | unsigned PhiNotMatchedCount = 0; | |||
| 3635 | if (!MatchPhiSet(ST, AddrSinkNewPhis, PhiNotMatchedCount)) { | |||
| 3636 | ST.destroyNewNodes(CommonType); | |||
| 3637 | return nullptr; | |||
| 3638 | } | |||
| 3639 | ||||
| 3640 | auto *Result = ST.Get(Map.find(Original)->second); | |||
| 3641 | if (Result) { | |||
| 3642 | NumMemoryInstsPhiCreated += ST.countNewPhiNodes() + PhiNotMatchedCount; | |||
| 3643 | NumMemoryInstsSelectCreated += ST.countNewSelectNodes(); | |||
| 3644 | } | |||
| 3645 | return Result; | |||
| 3646 | } | |||
| 3647 | ||||
| 3648 | /// Try to match PHI node to Candidate. | |||
| 3649 | /// Matcher tracks the matched Phi nodes. | |||
| 3650 | bool MatchPhiNode(PHINode *PHI, PHINode *Candidate, | |||
| 3651 | SmallSetVector<PHIPair, 8> &Matcher, | |||
| 3652 | PhiNodeSet &PhiNodesToMatch) { | |||
| 3653 | SmallVector<PHIPair, 8> WorkList; | |||
| 3654 | Matcher.insert({ PHI, Candidate }); | |||
| 3655 | SmallSet<PHINode *, 8> MatchedPHIs; | |||
| 3656 | MatchedPHIs.insert(PHI); | |||
| 3657 | WorkList.push_back({ PHI, Candidate }); | |||
| 3658 | SmallSet<PHIPair, 8> Visited; | |||
| 3659 | while (!WorkList.empty()) { | |||
| 3660 | auto Item = WorkList.pop_back_val(); | |||
| 3661 | if (!Visited.insert(Item).second) | |||
| 3662 | continue; | |||
| 3663 | // We iterate over all incoming values to Phi to compare them. | |||
| 3664 | // If values are different and both of them Phi and the first one is a | |||
| 3665 | // Phi we added (subject to match) and both of them is in the same basic | |||
| 3666 | // block then we can match our pair if values match. So we state that | |||
| 3667 | // these values match and add it to work list to verify that. | |||
| 3668 | for (auto B : Item.first->blocks()) { | |||
| 3669 | Value *FirstValue = Item.first->getIncomingValueForBlock(B); | |||
| 3670 | Value *SecondValue = Item.second->getIncomingValueForBlock(B); | |||
| 3671 | if (FirstValue == SecondValue) | |||
| 3672 | continue; | |||
| 3673 | ||||
| 3674 | PHINode *FirstPhi = dyn_cast<PHINode>(FirstValue); | |||
| 3675 | PHINode *SecondPhi = dyn_cast<PHINode>(SecondValue); | |||
| 3676 | ||||
| 3677 | // One of them is not Phi or | |||
| 3678 | // The first one is not Phi node from the set we'd like to match or | |||
| 3679 | // Phi nodes from different basic blocks then | |||
| 3680 | // we will not be able to match. | |||
| 3681 | if (!FirstPhi || !SecondPhi || !PhiNodesToMatch.count(FirstPhi) || | |||
| 3682 | FirstPhi->getParent() != SecondPhi->getParent()) | |||
| 3683 | return false; | |||
| 3684 | ||||
| 3685 | // If we already matched them then continue. | |||
| 3686 | if (Matcher.count({ FirstPhi, SecondPhi })) | |||
| 3687 | continue; | |||
| 3688 | // So the values are different and does not match. So we need them to | |||
| 3689 | // match. (But we register no more than one match per PHI node, so that | |||
| 3690 | // we won't later try to replace them twice.) | |||
| 3691 | if (MatchedPHIs.insert(FirstPhi).second) | |||
| 3692 | Matcher.insert({ FirstPhi, SecondPhi }); | |||
| 3693 | // But me must check it. | |||
| 3694 | WorkList.push_back({ FirstPhi, SecondPhi }); | |||
| 3695 | } | |||
| 3696 | } | |||
| 3697 | return true; | |||
| 3698 | } | |||
| 3699 | ||||
| 3700 | /// For the given set of PHI nodes (in the SimplificationTracker) try | |||
| 3701 | /// to find their equivalents. | |||
| 3702 | /// Returns false if this matching fails and creation of new Phi is disabled. | |||
| 3703 | bool MatchPhiSet(SimplificationTracker &ST, bool AllowNewPhiNodes, | |||
| 3704 | unsigned &PhiNotMatchedCount) { | |||
| 3705 | // Matched and PhiNodesToMatch iterate their elements in a deterministic | |||
| 3706 | // order, so the replacements (ReplacePhi) are also done in a deterministic | |||
| 3707 | // order. | |||
| 3708 | SmallSetVector<PHIPair, 8> Matched; | |||
| 3709 | SmallPtrSet<PHINode *, 8> WillNotMatch; | |||
| 3710 | PhiNodeSet &PhiNodesToMatch = ST.newPhiNodes(); | |||
| 3711 | while (PhiNodesToMatch.size()) { | |||
| 3712 | PHINode *PHI = *PhiNodesToMatch.begin(); | |||
| 3713 | ||||
| 3714 | // Add us, if no Phi nodes in the basic block we do not match. | |||
| 3715 | WillNotMatch.clear(); | |||
| 3716 | WillNotMatch.insert(PHI); | |||
| 3717 | ||||
| 3718 | // Traverse all Phis until we found equivalent or fail to do that. | |||
| 3719 | bool IsMatched = false; | |||
| 3720 | for (auto &P : PHI->getParent()->phis()) { | |||
| 3721 | if (&P == PHI) | |||
| 3722 | continue; | |||
| 3723 | if ((IsMatched = MatchPhiNode(PHI, &P, Matched, PhiNodesToMatch))) | |||
| 3724 | break; | |||
| 3725 | // If it does not match, collect all Phi nodes from matcher. | |||
| 3726 | // if we end up with no match, them all these Phi nodes will not match | |||
| 3727 | // later. | |||
| 3728 | for (auto M : Matched) | |||
| 3729 | WillNotMatch.insert(M.first); | |||
| 3730 | Matched.clear(); | |||
| 3731 | } | |||
| 3732 | if (IsMatched) { | |||
| 3733 | // Replace all matched values and erase them. | |||
| 3734 | for (auto MV : Matched) | |||
| 3735 | ST.ReplacePhi(MV.first, MV.second); | |||
| 3736 | Matched.clear(); | |||
| 3737 | continue; | |||
| 3738 | } | |||
| 3739 | // If we are not allowed to create new nodes then bail out. | |||
| 3740 | if (!AllowNewPhiNodes) | |||
| 3741 | return false; | |||
| 3742 | // Just remove all seen values in matcher. They will not match anything. | |||
| 3743 | PhiNotMatchedCount += WillNotMatch.size(); | |||
| 3744 | for (auto *P : WillNotMatch) | |||
| 3745 | PhiNodesToMatch.erase(P); | |||
| 3746 | } | |||
| 3747 | return true; | |||
| 3748 | } | |||
| 3749 | /// Fill the placeholders with values from predecessors and simplify them. | |||
| 3750 | void FillPlaceholders(FoldAddrToValueMapping &Map, | |||
| 3751 | SmallVectorImpl<Value *> &TraverseOrder, | |||
| 3752 | SimplificationTracker &ST) { | |||
| 3753 | while (!TraverseOrder.empty()) { | |||
| 3754 | Value *Current = TraverseOrder.pop_back_val(); | |||
| 3755 | assert(Map.find(Current) != Map.end() && "No node to fill!!!")((void)0); | |||
| 3756 | Value *V = Map[Current]; | |||
| 3757 | ||||
| 3758 | if (SelectInst *Select = dyn_cast<SelectInst>(V)) { | |||
| 3759 | // CurrentValue also must be Select. | |||
| 3760 | auto *CurrentSelect = cast<SelectInst>(Current); | |||
| 3761 | auto *TrueValue = CurrentSelect->getTrueValue(); | |||
| 3762 | assert(Map.find(TrueValue) != Map.end() && "No True Value!")((void)0); | |||
| 3763 | Select->setTrueValue(ST.Get(Map[TrueValue])); | |||
| 3764 | auto *FalseValue = CurrentSelect->getFalseValue(); | |||
| 3765 | assert(Map.find(FalseValue) != Map.end() && "No False Value!")((void)0); | |||
| 3766 | Select->setFalseValue(ST.Get(Map[FalseValue])); | |||
| 3767 | } else { | |||
| 3768 | // Must be a Phi node then. | |||
| 3769 | auto *PHI = cast<PHINode>(V); | |||
| 3770 | // Fill the Phi node with values from predecessors. | |||
| 3771 | for (auto *B : predecessors(PHI->getParent())) { | |||
| 3772 | Value *PV = cast<PHINode>(Current)->getIncomingValueForBlock(B); | |||
| 3773 | assert(Map.find(PV) != Map.end() && "No predecessor Value!")((void)0); | |||
| 3774 | PHI->addIncoming(ST.Get(Map[PV]), B); | |||
| 3775 | } | |||
| 3776 | } | |||
| 3777 | Map[Current] = ST.Simplify(V); | |||
| 3778 | } | |||
| 3779 | } | |||
| 3780 | ||||
| 3781 | /// Starting from original value recursively iterates over def-use chain up to | |||
| 3782 | /// known ending values represented in a map. For each traversed phi/select | |||
| 3783 | /// inserts a placeholder Phi or Select. | |||
| 3784 | /// Reports all new created Phi/Select nodes by adding them to set. | |||
| 3785 | /// Also reports and order in what values have been traversed. | |||
| 3786 | void InsertPlaceholders(FoldAddrToValueMapping &Map, | |||
| 3787 | SmallVectorImpl<Value *> &TraverseOrder, | |||
| 3788 | SimplificationTracker &ST) { | |||
| 3789 | SmallVector<Value *, 32> Worklist; | |||
| 3790 | assert((isa<PHINode>(Original) || isa<SelectInst>(Original)) &&((void)0) | |||
| 3791 | "Address must be a Phi or Select node")((void)0); | |||
| 3792 | auto *Dummy = UndefValue::get(CommonType); | |||
| 3793 | Worklist.push_back(Original); | |||
| 3794 | while (!Worklist.empty()) { | |||
| 3795 | Value *Current = Worklist.pop_back_val(); | |||
| 3796 | // if it is already visited or it is an ending value then skip it. | |||
| 3797 | if (Map.find(Current) != Map.end()) | |||
| 3798 | continue; | |||
| 3799 | TraverseOrder.push_back(Current); | |||
| 3800 | ||||
| 3801 | // CurrentValue must be a Phi node or select. All others must be covered | |||
| 3802 | // by anchors. | |||
| 3803 | if (SelectInst *CurrentSelect = dyn_cast<SelectInst>(Current)) { | |||
| 3804 | // Is it OK to get metadata from OrigSelect?! | |||
| 3805 | // Create a Select placeholder with dummy value. | |||
| 3806 | SelectInst *Select = SelectInst::Create( | |||
| 3807 | CurrentSelect->getCondition(), Dummy, Dummy, | |||
| 3808 | CurrentSelect->getName(), CurrentSelect, CurrentSelect); | |||
| 3809 | Map[Current] = Select; | |||
| 3810 | ST.insertNewSelect(Select); | |||
| 3811 | // We are interested in True and False values. | |||
| 3812 | Worklist.push_back(CurrentSelect->getTrueValue()); | |||
| 3813 | Worklist.push_back(CurrentSelect->getFalseValue()); | |||
| 3814 | } else { | |||
| 3815 | // It must be a Phi node then. | |||
| 3816 | PHINode *CurrentPhi = cast<PHINode>(Current); | |||
| 3817 | unsigned PredCount = CurrentPhi->getNumIncomingValues(); | |||
| 3818 | PHINode *PHI = | |||
| 3819 | PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi); | |||
| 3820 | Map[Current] = PHI; | |||
| 3821 | ST.insertNewPhi(PHI); | |||
| 3822 | append_range(Worklist, CurrentPhi->incoming_values()); | |||
| 3823 | } | |||
| 3824 | } | |||
| 3825 | } | |||
| 3826 | ||||
| 3827 | bool addrModeCombiningAllowed() { | |||
| 3828 | if (DisableComplexAddrModes) | |||
| 3829 | return false; | |||
| 3830 | switch (DifferentField) { | |||
| 3831 | default: | |||
| 3832 | return false; | |||
| 3833 | case ExtAddrMode::BaseRegField: | |||
| 3834 | return AddrSinkCombineBaseReg; | |||
| 3835 | case ExtAddrMode::BaseGVField: | |||
| 3836 | return AddrSinkCombineBaseGV; | |||
| 3837 | case ExtAddrMode::BaseOffsField: | |||
| 3838 | return AddrSinkCombineBaseOffs; | |||
| 3839 | case ExtAddrMode::ScaledRegField: | |||
| 3840 | return AddrSinkCombineScaledReg; | |||
| 3841 | } | |||
| 3842 | } | |||
| 3843 | }; | |||
| 3844 | } // end anonymous namespace | |||
| 3845 | ||||
| 3846 | /// Try adding ScaleReg*Scale to the current addressing mode. | |||
| 3847 | /// Return true and update AddrMode if this addr mode is legal for the target, | |||
| 3848 | /// false if not. | |||
| 3849 | bool AddressingModeMatcher::matchScaledValue(Value *ScaleReg, int64_t Scale, | |||
| 3850 | unsigned Depth) { | |||
| 3851 | // If Scale is 1, then this is the same as adding ScaleReg to the addressing | |||
| 3852 | // mode. Just process that directly. | |||
| 3853 | if (Scale == 1) | |||
| 3854 | return matchAddr(ScaleReg, Depth); | |||
| 3855 | ||||
| 3856 | // If the scale is 0, it takes nothing to add this. | |||
| 3857 | if (Scale == 0) | |||
| 3858 | return true; | |||
| 3859 | ||||
| 3860 | // If we already have a scale of this value, we can add to it, otherwise, we | |||
| 3861 | // need an available scale field. | |||
| 3862 | if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg) | |||
| 3863 | return false; | |||
| 3864 | ||||
| 3865 | ExtAddrMode TestAddrMode = AddrMode; | |||
| 3866 | ||||
| 3867 | // Add scale to turn X*4+X*3 -> X*7. This could also do things like | |||
| 3868 | // [A+B + A*7] -> [B+A*8]. | |||
| 3869 | TestAddrMode.Scale += Scale; | |||
| 3870 | TestAddrMode.ScaledReg = ScaleReg; | |||
| 3871 | ||||
| 3872 | // If the new address isn't legal, bail out. | |||
| 3873 | if (!TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) | |||
| 3874 | return false; | |||
| 3875 | ||||
| 3876 | // It was legal, so commit it. | |||
| 3877 | AddrMode = TestAddrMode; | |||
| 3878 | ||||
| 3879 | // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now | |||
| 3880 | // to see if ScaleReg is actually X+C. If so, we can turn this into adding | |||
| 3881 | // X*Scale + C*Scale to addr mode. If we found available IV increment, do not | |||
| 3882 | // go any further: we can reuse it and cannot eliminate it. | |||
| 3883 | ConstantInt *CI = nullptr; Value *AddLHS = nullptr; | |||
| 3884 | if (isa<Instruction>(ScaleReg) && // not a constant expr. | |||
| 3885 | match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI))) && | |||
| 3886 | !isIVIncrement(ScaleReg, &LI) && CI->getValue().isSignedIntN(64)) { | |||
| 3887 | TestAddrMode.InBounds = false; | |||
| 3888 | TestAddrMode.ScaledReg = AddLHS; | |||
| 3889 | TestAddrMode.BaseOffs += CI->getSExtValue() * TestAddrMode.Scale; | |||
| 3890 | ||||
| 3891 | // If this addressing mode is legal, commit it and remember that we folded | |||
| 3892 | // this instruction. | |||
| 3893 | if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) { | |||
| 3894 | AddrModeInsts.push_back(cast<Instruction>(ScaleReg)); | |||
| 3895 | AddrMode = TestAddrMode; | |||
| 3896 | return true; | |||
| 3897 | } | |||
| 3898 | // Restore status quo. | |||
| 3899 | TestAddrMode = AddrMode; | |||
| 3900 | } | |||
| 3901 | ||||
| 3902 | // If this is an add recurrence with a constant step, return the increment | |||
| 3903 | // instruction and the canonicalized step. | |||
| 3904 | auto GetConstantStep = [this](const Value * V) | |||
| 3905 | ->Optional<std::pair<Instruction *, APInt> > { | |||
| 3906 | auto *PN = dyn_cast<PHINode>(V); | |||
| 3907 | if (!PN) | |||
| 3908 | return None; | |||
| 3909 | auto IVInc = getIVIncrement(PN, &LI); | |||
| 3910 | if (!IVInc) | |||
| 3911 | return None; | |||
| 3912 | // TODO: The result of the intrinsics above is two-compliment. However when | |||
| 3913 | // IV inc is expressed as add or sub, iv.next is potentially a poison value. | |||
| 3914 | // If it has nuw or nsw flags, we need to make sure that these flags are | |||
| 3915 | // inferrable at the point of memory instruction. Otherwise we are replacing | |||
| 3916 | // well-defined two-compliment computation with poison. Currently, to avoid | |||
| 3917 | // potentially complex analysis needed to prove this, we reject such cases. | |||
| 3918 | if (auto *OIVInc = dyn_cast<OverflowingBinaryOperator>(IVInc->first)) | |||
| 3919 | if (OIVInc->hasNoSignedWrap() || OIVInc->hasNoUnsignedWrap()) | |||
| 3920 | return None; | |||
| 3921 | if (auto *ConstantStep = dyn_cast<ConstantInt>(IVInc->second)) | |||
| 3922 | return std::make_pair(IVInc->first, ConstantStep->getValue()); | |||
| 3923 | return None; | |||
| 3924 | }; | |||
| 3925 | ||||
| 3926 | // Try to account for the following special case: | |||
| 3927 | // 1. ScaleReg is an inductive variable; | |||
| 3928 | // 2. We use it with non-zero offset; | |||
| 3929 | // 3. IV's increment is available at the point of memory instruction. | |||
| 3930 | // | |||
| 3931 | // In this case, we may reuse the IV increment instead of the IV Phi to | |||
| 3932 | // achieve the following advantages: | |||
| 3933 | // 1. If IV step matches the offset, we will have no need in the offset; | |||
| 3934 | // 2. Even if they don't match, we will reduce the overlap of living IV | |||
| 3935 | // and IV increment, that will potentially lead to better register | |||
| 3936 | // assignment. | |||
| 3937 | if (AddrMode.BaseOffs) { | |||
| 3938 | if (auto IVStep = GetConstantStep(ScaleReg)) { | |||
| 3939 | Instruction *IVInc = IVStep->first; | |||
| 3940 | // The following assert is important to ensure a lack of infinite loops. | |||
| 3941 | // This transforms is (intentionally) the inverse of the one just above. | |||
| 3942 | // If they don't agree on the definition of an increment, we'd alternate | |||
| 3943 | // back and forth indefinitely. | |||
| 3944 | assert(isIVIncrement(IVInc, &LI) && "implied by GetConstantStep")((void)0); | |||
| 3945 | APInt Step = IVStep->second; | |||
| 3946 | APInt Offset = Step * AddrMode.Scale; | |||
| 3947 | if (Offset.isSignedIntN(64)) { | |||
| 3948 | TestAddrMode.InBounds = false; | |||
| 3949 | TestAddrMode.ScaledReg = IVInc; | |||
| 3950 | TestAddrMode.BaseOffs -= Offset.getLimitedValue(); | |||
| 3951 | // If this addressing mode is legal, commit it.. | |||
| 3952 | // (Note that we defer the (expensive) domtree base legality check | |||
| 3953 | // to the very last possible point.) | |||
| 3954 | if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace) && | |||
| 3955 | getDTFn().dominates(IVInc, MemoryInst)) { | |||
| 3956 | AddrModeInsts.push_back(cast<Instruction>(IVInc)); | |||
| 3957 | AddrMode = TestAddrMode; | |||
| 3958 | return true; | |||
| 3959 | } | |||
| 3960 | // Restore status quo. | |||
| 3961 | TestAddrMode = AddrMode; | |||
| 3962 | } | |||
| 3963 | } | |||
| 3964 | } | |||
| 3965 | ||||
| 3966 | // Otherwise, just return what we have. | |||
| 3967 | return true; | |||
| 3968 | } | |||
| 3969 | ||||
| 3970 | /// This is a little filter, which returns true if an addressing computation | |||
| 3971 | /// involving I might be folded into a load/store accessing it. | |||
| 3972 | /// This doesn't need to be perfect, but needs to accept at least | |||
| 3973 | /// the set of instructions that MatchOperationAddr can. | |||
| 3974 | static bool MightBeFoldableInst(Instruction *I) { | |||
| 3975 | switch (I->getOpcode()) { | |||
| 3976 | case Instruction::BitCast: | |||
| 3977 | case Instruction::AddrSpaceCast: | |||
| 3978 | // Don't touch identity bitcasts. | |||
| 3979 | if (I->getType() == I->getOperand(0)->getType()) | |||
| 3980 | return false; | |||
| 3981 | return I->getType()->isIntOrPtrTy(); | |||
| 3982 | case Instruction::PtrToInt: | |||
| 3983 | // PtrToInt is always a noop, as we know that the int type is pointer sized. | |||
| 3984 | return true; | |||
| 3985 | case Instruction::IntToPtr: | |||
| 3986 | // We know the input is intptr_t, so this is foldable. | |||
| 3987 | return true; | |||
| 3988 | case Instruction::Add: | |||
| 3989 | return true; | |||
| 3990 | case Instruction::Mul: | |||
| 3991 | case Instruction::Shl: | |||
| 3992 | // Can only handle X*C and X << C. | |||
| 3993 | return isa<ConstantInt>(I->getOperand(1)); | |||
| 3994 | case Instruction::GetElementPtr: | |||
| 3995 | return true; | |||
| 3996 | default: | |||
| 3997 | return false; | |||
| 3998 | } | |||
| 3999 | } | |||
| 4000 | ||||
| 4001 | /// Check whether or not \p Val is a legal instruction for \p TLI. | |||
| 4002 | /// \note \p Val is assumed to be the product of some type promotion. | |||
| 4003 | /// Therefore if \p Val has an undefined state in \p TLI, this is assumed | |||
| 4004 | /// to be legal, as the non-promoted value would have had the same state. | |||
| 4005 | static bool isPromotedInstructionLegal(const TargetLowering &TLI, | |||
| 4006 | const DataLayout &DL, Value *Val) { | |||
| 4007 | Instruction *PromotedInst = dyn_cast<Instruction>(Val); | |||
| 4008 | if (!PromotedInst) | |||
| 4009 | return false; | |||
| 4010 | int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode()); | |||
| 4011 | // If the ISDOpcode is undefined, it was undefined before the promotion. | |||
| 4012 | if (!ISDOpcode) | |||
| 4013 | return true; | |||
| 4014 | // Otherwise, check if the promoted instruction is legal or not. | |||
| 4015 | return TLI.isOperationLegalOrCustom( | |||
| 4016 | ISDOpcode, TLI.getValueType(DL, PromotedInst->getType())); | |||
| 4017 | } | |||
| 4018 | ||||
| 4019 | namespace { | |||
| 4020 | ||||
| 4021 | /// Hepler class to perform type promotion. | |||
| 4022 | class TypePromotionHelper { | |||
| 4023 | /// Utility function to add a promoted instruction \p ExtOpnd to | |||
| 4024 | /// \p PromotedInsts and record the type of extension we have seen. | |||
| 4025 | static void addPromotedInst(InstrToOrigTy &PromotedInsts, | |||
| 4026 | Instruction *ExtOpnd, | |||
| 4027 | bool IsSExt) { | |||
| 4028 | ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension; | |||
| 4029 | InstrToOrigTy::iterator It = PromotedInsts.find(ExtOpnd); | |||
| 4030 | if (It != PromotedInsts.end()) { | |||
| 4031 | // If the new extension is same as original, the information in | |||
| 4032 | // PromotedInsts[ExtOpnd] is still correct. | |||
| 4033 | if (It->second.getInt() == ExtTy) | |||
| 4034 | return; | |||
| 4035 | ||||
| 4036 | // Now the new extension is different from old extension, we make | |||
| 4037 | // the type information invalid by setting extension type to | |||
| 4038 | // BothExtension. | |||
| 4039 | ExtTy = BothExtension; | |||
| 4040 | } | |||
| 4041 | PromotedInsts[ExtOpnd] = TypeIsSExt(ExtOpnd->getType(), ExtTy); | |||
| 4042 | } | |||
| 4043 | ||||
| 4044 | /// Utility function to query the original type of instruction \p Opnd | |||
| 4045 | /// with a matched extension type. If the extension doesn't match, we | |||
| 4046 | /// cannot use the information we had on the original type. | |||
| 4047 | /// BothExtension doesn't match any extension type. | |||
| 4048 | static const Type *getOrigType(const InstrToOrigTy &PromotedInsts, | |||
| 4049 | Instruction *Opnd, | |||
| 4050 | bool IsSExt) { | |||
| 4051 | ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension; | |||
| 4052 | InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd); | |||
| 4053 | if (It != PromotedInsts.end() && It->second.getInt() == ExtTy) | |||
| 4054 | return It->second.getPointer(); | |||
| 4055 | return nullptr; | |||
| 4056 | } | |||
| 4057 | ||||
| 4058 | /// Utility function to check whether or not a sign or zero extension | |||
| 4059 | /// of \p Inst with \p ConsideredExtType can be moved through \p Inst by | |||
| 4060 | /// either using the operands of \p Inst or promoting \p Inst. | |||
| 4061 | /// The type of the extension is defined by \p IsSExt. | |||
| 4062 | /// In other words, check if: | |||
| 4063 | /// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType. | |||
| 4064 | /// #1 Promotion applies: | |||
| 4065 | /// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...). | |||
| 4066 | /// #2 Operand reuses: | |||
| 4067 | /// ext opnd1 to ConsideredExtType. | |||
| 4068 | /// \p PromotedInsts maps the instructions to their type before promotion. | |||
| 4069 | static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType, | |||
| 4070 | const InstrToOrigTy &PromotedInsts, bool IsSExt); | |||
| 4071 | ||||
| 4072 | /// Utility function to determine if \p OpIdx should be promoted when | |||
| 4073 | /// promoting \p Inst. | |||
| 4074 | static bool shouldExtOperand(const Instruction *Inst, int OpIdx) { | |||
| 4075 | return !(isa<SelectInst>(Inst) && OpIdx == 0); | |||
| 4076 | } | |||
| 4077 | ||||
| 4078 | /// Utility function to promote the operand of \p Ext when this | |||
| 4079 | /// operand is a promotable trunc or sext or zext. | |||
| 4080 | /// \p PromotedInsts maps the instructions to their type before promotion. | |||
| 4081 | /// \p CreatedInstsCost[out] contains the cost of all instructions | |||
| 4082 | /// created to promote the operand of Ext. | |||
| 4083 | /// Newly added extensions are inserted in \p Exts. | |||
| 4084 | /// Newly added truncates are inserted in \p Truncs. | |||
| 4085 | /// Should never be called directly. | |||
| 4086 | /// \return The promoted value which is used instead of Ext. | |||
| 4087 | static Value *promoteOperandForTruncAndAnyExt( | |||
| 4088 | Instruction *Ext, TypePromotionTransaction &TPT, | |||
| 4089 | InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost, | |||
| 4090 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4091 | SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI); | |||
| 4092 | ||||
| 4093 | /// Utility function to promote the operand of \p Ext when this | |||
| 4094 | /// operand is promotable and is not a supported trunc or sext. | |||
| 4095 | /// \p PromotedInsts maps the instructions to their type before promotion. | |||
| 4096 | /// \p CreatedInstsCost[out] contains the cost of all the instructions | |||
| 4097 | /// created to promote the operand of Ext. | |||
| 4098 | /// Newly added extensions are inserted in \p Exts. | |||
| 4099 | /// Newly added truncates are inserted in \p Truncs. | |||
| 4100 | /// Should never be called directly. | |||
| 4101 | /// \return The promoted value which is used instead of Ext. | |||
| 4102 | static Value *promoteOperandForOther(Instruction *Ext, | |||
| 4103 | TypePromotionTransaction &TPT, | |||
| 4104 | InstrToOrigTy &PromotedInsts, | |||
| 4105 | unsigned &CreatedInstsCost, | |||
| 4106 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4107 | SmallVectorImpl<Instruction *> *Truncs, | |||
| 4108 | const TargetLowering &TLI, bool IsSExt); | |||
| 4109 | ||||
| 4110 | /// \see promoteOperandForOther. | |||
| 4111 | static Value *signExtendOperandForOther( | |||
| 4112 | Instruction *Ext, TypePromotionTransaction &TPT, | |||
| 4113 | InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost, | |||
| 4114 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4115 | SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) { | |||
| 4116 | return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost, | |||
| 4117 | Exts, Truncs, TLI, true); | |||
| 4118 | } | |||
| 4119 | ||||
| 4120 | /// \see promoteOperandForOther. | |||
| 4121 | static Value *zeroExtendOperandForOther( | |||
| 4122 | Instruction *Ext, TypePromotionTransaction &TPT, | |||
| 4123 | InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost, | |||
| 4124 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4125 | SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) { | |||
| 4126 | return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost, | |||
| 4127 | Exts, Truncs, TLI, false); | |||
| 4128 | } | |||
| 4129 | ||||
| 4130 | public: | |||
| 4131 | /// Type for the utility function that promotes the operand of Ext. | |||
| 4132 | using Action = Value *(*)(Instruction *Ext, TypePromotionTransaction &TPT, | |||
| 4133 | InstrToOrigTy &PromotedInsts, | |||
| 4134 | unsigned &CreatedInstsCost, | |||
| 4135 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4136 | SmallVectorImpl<Instruction *> *Truncs, | |||
| 4137 | const TargetLowering &TLI); | |||
| 4138 | ||||
| 4139 | /// Given a sign/zero extend instruction \p Ext, return the appropriate | |||
| 4140 | /// action to promote the operand of \p Ext instead of using Ext. | |||
| 4141 | /// \return NULL if no promotable action is possible with the current | |||
| 4142 | /// sign extension. | |||
| 4143 | /// \p InsertedInsts keeps track of all the instructions inserted by the | |||
| 4144 | /// other CodeGenPrepare optimizations. This information is important | |||
| 4145 | /// because we do not want to promote these instructions as CodeGenPrepare | |||
| 4146 | /// will reinsert them later. Thus creating an infinite loop: create/remove. | |||
| 4147 | /// \p PromotedInsts maps the instructions to their type before promotion. | |||
| 4148 | static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedInsts, | |||
| 4149 | const TargetLowering &TLI, | |||
| 4150 | const InstrToOrigTy &PromotedInsts); | |||
| 4151 | }; | |||
| 4152 | ||||
| 4153 | } // end anonymous namespace | |||
| 4154 | ||||
| 4155 | bool TypePromotionHelper::canGetThrough(const Instruction *Inst, | |||
| 4156 | Type *ConsideredExtType, | |||
| 4157 | const InstrToOrigTy &PromotedInsts, | |||
| 4158 | bool IsSExt) { | |||
| 4159 | // The promotion helper does not know how to deal with vector types yet. | |||
| 4160 | // To be able to fix that, we would need to fix the places where we | |||
| 4161 | // statically extend, e.g., constants and such. | |||
| 4162 | if (Inst->getType()->isVectorTy()) | |||
| 4163 | return false; | |||
| 4164 | ||||
| 4165 | // We can always get through zext. | |||
| 4166 | if (isa<ZExtInst>(Inst)) | |||
| 4167 | return true; | |||
| 4168 | ||||
| 4169 | // sext(sext) is ok too. | |||
| 4170 | if (IsSExt && isa<SExtInst>(Inst)) | |||
| 4171 | return true; | |||
| 4172 | ||||
| 4173 | // We can get through binary operator, if it is legal. In other words, the | |||
| 4174 | // binary operator must have a nuw or nsw flag. | |||
| 4175 | const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst); | |||
| 4176 | if (isa_and_nonnull<OverflowingBinaryOperator>(BinOp) && | |||
| 4177 | ((!IsSExt && BinOp->hasNoUnsignedWrap()) || | |||
| 4178 | (IsSExt && BinOp->hasNoSignedWrap()))) | |||
| 4179 | return true; | |||
| 4180 | ||||
| 4181 | // ext(and(opnd, cst)) --> and(ext(opnd), ext(cst)) | |||
| 4182 | if ((Inst->getOpcode() == Instruction::And || | |||
| 4183 | Inst->getOpcode() == Instruction::Or)) | |||
| 4184 | return true; | |||
| 4185 | ||||
| 4186 | // ext(xor(opnd, cst)) --> xor(ext(opnd), ext(cst)) | |||
| 4187 | if (Inst->getOpcode() == Instruction::Xor) { | |||
| 4188 | const ConstantInt *Cst = dyn_cast<ConstantInt>(Inst->getOperand(1)); | |||
| 4189 | // Make sure it is not a NOT. | |||
| 4190 | if (Cst && !Cst->getValue().isAllOnesValue()) | |||
| 4191 | return true; | |||
| 4192 | } | |||
| 4193 | ||||
| 4194 | // zext(shrl(opnd, cst)) --> shrl(zext(opnd), zext(cst)) | |||
| 4195 | // It may change a poisoned value into a regular value, like | |||
| 4196 | // zext i32 (shrl i8 %val, 12) --> shrl i32 (zext i8 %val), 12 | |||
| 4197 | // poisoned value regular value | |||
| 4198 | // It should be OK since undef covers valid value. | |||
| 4199 | if (Inst->getOpcode() == Instruction::LShr && !IsSExt) | |||
| 4200 | return true; | |||
| 4201 | ||||
| 4202 | // and(ext(shl(opnd, cst)), cst) --> and(shl(ext(opnd), ext(cst)), cst) | |||
| 4203 | // It may change a poisoned value into a regular value, like | |||
| 4204 | // zext i32 (shl i8 %val, 12) --> shl i32 (zext i8 %val), 12 | |||
| 4205 | // poisoned value regular value | |||
| 4206 | // It should be OK since undef covers valid value. | |||
| 4207 | if (Inst->getOpcode() == Instruction::Shl && Inst->hasOneUse()) { | |||
| 4208 | const auto *ExtInst = cast<const Instruction>(*Inst->user_begin()); | |||
| 4209 | if (ExtInst->hasOneUse()) { | |||
| 4210 | const auto *AndInst = dyn_cast<const Instruction>(*ExtInst->user_begin()); | |||
| 4211 | if (AndInst && AndInst->getOpcode() == Instruction::And) { | |||
| 4212 | const auto *Cst = dyn_cast<ConstantInt>(AndInst->getOperand(1)); | |||
| 4213 | if (Cst && | |||
| 4214 | Cst->getValue().isIntN(Inst->getType()->getIntegerBitWidth())) | |||
| 4215 | return true; | |||
| 4216 | } | |||
| 4217 | } | |||
| 4218 | } | |||
| 4219 | ||||
| 4220 | // Check if we can do the following simplification. | |||
| 4221 | // ext(trunc(opnd)) --> ext(opnd) | |||
| 4222 | if (!isa<TruncInst>(Inst)) | |||
| 4223 | return false; | |||
| 4224 | ||||
| 4225 | Value *OpndVal = Inst->getOperand(0); | |||
| 4226 | // Check if we can use this operand in the extension. | |||
| 4227 | // If the type is larger than the result type of the extension, we cannot. | |||
| 4228 | if (!OpndVal->getType()->isIntegerTy() || | |||
| 4229 | OpndVal->getType()->getIntegerBitWidth() > | |||
| 4230 | ConsideredExtType->getIntegerBitWidth()) | |||
| 4231 | return false; | |||
| 4232 | ||||
| 4233 | // If the operand of the truncate is not an instruction, we will not have | |||
| 4234 | // any information on the dropped bits. | |||
| 4235 | // (Actually we could for constant but it is not worth the extra logic). | |||
| 4236 | Instruction *Opnd = dyn_cast<Instruction>(OpndVal); | |||
| 4237 | if (!Opnd) | |||
| 4238 | return false; | |||
| 4239 | ||||
| 4240 | // Check if the source of the type is narrow enough. | |||
| 4241 | // I.e., check that trunc just drops extended bits of the same kind of | |||
| 4242 | // the extension. | |||
| 4243 | // #1 get the type of the operand and check the kind of the extended bits. | |||
| 4244 | const Type *OpndType = getOrigType(PromotedInsts, Opnd, IsSExt); | |||
| 4245 | if (OpndType) | |||
| 4246 | ; | |||
| 4247 | else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd))) | |||
| 4248 | OpndType = Opnd->getOperand(0)->getType(); | |||
| 4249 | else | |||
| 4250 | return false; | |||
| 4251 | ||||
| 4252 | // #2 check that the truncate just drops extended bits. | |||
| 4253 | return Inst->getType()->getIntegerBitWidth() >= | |||
| 4254 | OpndType->getIntegerBitWidth(); | |||
| 4255 | } | |||
| 4256 | ||||
| 4257 | TypePromotionHelper::Action TypePromotionHelper::getAction( | |||
| 4258 | Instruction *Ext, const SetOfInstrs &InsertedInsts, | |||
| 4259 | const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) { | |||
| 4260 | assert((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&((void)0) | |||
| 4261 | "Unexpected instruction type")((void)0); | |||
| 4262 | Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0)); | |||
| 4263 | Type *ExtTy = Ext->getType(); | |||
| 4264 | bool IsSExt = isa<SExtInst>(Ext); | |||
| 4265 | // If the operand of the extension is not an instruction, we cannot | |||
| 4266 | // get through. | |||
| 4267 | // If it, check we can get through. | |||
| 4268 | if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt)) | |||
| 4269 | return nullptr; | |||
| 4270 | ||||
| 4271 | // Do not promote if the operand has been added by codegenprepare. | |||
| 4272 | // Otherwise, it means we are undoing an optimization that is likely to be | |||
| 4273 | // redone, thus causing potential infinite loop. | |||
| 4274 | if (isa<TruncInst>(ExtOpnd) && InsertedInsts.count(ExtOpnd)) | |||
| 4275 | return nullptr; | |||
| 4276 | ||||
| 4277 | // SExt or Trunc instructions. | |||
| 4278 | // Return the related handler. | |||
| 4279 | if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) || | |||
| 4280 | isa<ZExtInst>(ExtOpnd)) | |||
| 4281 | return promoteOperandForTruncAndAnyExt; | |||
| 4282 | ||||
| 4283 | // Regular instruction. | |||
| 4284 | // Abort early if we will have to insert non-free instructions. | |||
| 4285 | if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType())) | |||
| 4286 | return nullptr; | |||
| 4287 | return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther; | |||
| 4288 | } | |||
| 4289 | ||||
| 4290 | Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt( | |||
| 4291 | Instruction *SExt, TypePromotionTransaction &TPT, | |||
| 4292 | InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost, | |||
| 4293 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4294 | SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) { | |||
| 4295 | // By construction, the operand of SExt is an instruction. Otherwise we cannot | |||
| 4296 | // get through it and this method should not be called. | |||
| 4297 | Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0)); | |||
| 4298 | Value *ExtVal = SExt; | |||
| 4299 | bool HasMergedNonFreeExt = false; | |||
| 4300 | if (isa<ZExtInst>(SExtOpnd)) { | |||
| 4301 | // Replace s|zext(zext(opnd)) | |||
| 4302 | // => zext(opnd). | |||
| 4303 | HasMergedNonFreeExt = !TLI.isExtFree(SExtOpnd); | |||
| 4304 | Value *ZExt = | |||
| 4305 | TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType()); | |||
| 4306 | TPT.replaceAllUsesWith(SExt, ZExt); | |||
| 4307 | TPT.eraseInstruction(SExt); | |||
| 4308 | ExtVal = ZExt; | |||
| 4309 | } else { | |||
| 4310 | // Replace z|sext(trunc(opnd)) or sext(sext(opnd)) | |||
| 4311 | // => z|sext(opnd). | |||
| 4312 | TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0)); | |||
| 4313 | } | |||
| 4314 | CreatedInstsCost = 0; | |||
| 4315 | ||||
| 4316 | // Remove dead code. | |||
| 4317 | if (SExtOpnd->use_empty()) | |||
| 4318 | TPT.eraseInstruction(SExtOpnd); | |||
| 4319 | ||||
| 4320 | // Check if the extension is still needed. | |||
| 4321 | Instruction *ExtInst = dyn_cast<Instruction>(ExtVal); | |||
| 4322 | if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) { | |||
| 4323 | if (ExtInst) { | |||
| 4324 | if (Exts) | |||
| 4325 | Exts->push_back(ExtInst); | |||
| 4326 | CreatedInstsCost = !TLI.isExtFree(ExtInst) && !HasMergedNonFreeExt; | |||
| 4327 | } | |||
| 4328 | return ExtVal; | |||
| 4329 | } | |||
| 4330 | ||||
| 4331 | // At this point we have: ext ty opnd to ty. | |||
| 4332 | // Reassign the uses of ExtInst to the opnd and remove ExtInst. | |||
| 4333 | Value *NextVal = ExtInst->getOperand(0); | |||
| 4334 | TPT.eraseInstruction(ExtInst, NextVal); | |||
| 4335 | return NextVal; | |||
| 4336 | } | |||
| 4337 | ||||
| 4338 | Value *TypePromotionHelper::promoteOperandForOther( | |||
| 4339 | Instruction *Ext, TypePromotionTransaction &TPT, | |||
| 4340 | InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost, | |||
| 4341 | SmallVectorImpl<Instruction *> *Exts, | |||
| 4342 | SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI, | |||
| 4343 | bool IsSExt) { | |||
| 4344 | // By construction, the operand of Ext is an instruction. Otherwise we cannot | |||
| 4345 | // get through it and this method should not be called. | |||
| 4346 | Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0)); | |||
| 4347 | CreatedInstsCost = 0; | |||
| 4348 | if (!ExtOpnd->hasOneUse()) { | |||
| 4349 | // ExtOpnd will be promoted. | |||
| 4350 | // All its uses, but Ext, will need to use a truncated value of the | |||
| 4351 | // promoted version. | |||
| 4352 | // Create the truncate now. | |||
| 4353 | Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType()); | |||
| 4354 | if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) { | |||
| 4355 | // Insert it just after the definition. | |||
| 4356 | ITrunc->moveAfter(ExtOpnd); | |||
| 4357 | if (Truncs) | |||
| 4358 | Truncs->push_back(ITrunc); | |||
| 4359 | } | |||
| 4360 | ||||
| 4361 | TPT.replaceAllUsesWith(ExtOpnd, Trunc); | |||
| 4362 | // Restore the operand of Ext (which has been replaced by the previous call | |||
| 4363 | // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext. | |||
| 4364 | TPT.setOperand(Ext, 0, ExtOpnd); | |||
| 4365 | } | |||
| 4366 | ||||
| 4367 | // Get through the Instruction: | |||
| 4368 | // 1. Update its type. | |||
| 4369 | // 2. Replace the uses of Ext by Inst. | |||
| 4370 | // 3. Extend each operand that needs to be extended. | |||
| 4371 | ||||
| 4372 | // Remember the original type of the instruction before promotion. | |||
| 4373 | // This is useful to know that the high bits are sign extended bits. | |||
| 4374 | addPromotedInst(PromotedInsts, ExtOpnd, IsSExt); | |||
| 4375 | // Step #1. | |||
| 4376 | TPT.mutateType(ExtOpnd, Ext->getType()); | |||
| 4377 | // Step #2. | |||
| 4378 | TPT.replaceAllUsesWith(Ext, ExtOpnd); | |||
| 4379 | // Step #3. | |||
| 4380 | Instruction *ExtForOpnd = Ext; | |||
| 4381 | ||||
| 4382 | LLVM_DEBUG(dbgs() << "Propagate Ext to operands\n")do { } while (false); | |||
| 4383 | for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx; | |||
| 4384 | ++OpIdx) { | |||
| 4385 | LLVM_DEBUG(dbgs() << "Operand:\n" << *(ExtOpnd->getOperand(OpIdx)) << '\n')do { } while (false); | |||
| 4386 | if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() || | |||
| 4387 | !shouldExtOperand(ExtOpnd, OpIdx)) { | |||
| 4388 | LLVM_DEBUG(dbgs() << "No need to propagate\n")do { } while (false); | |||
| 4389 | continue; | |||
| 4390 | } | |||
| 4391 | // Check if we can statically extend the operand. | |||
| 4392 | Value *Opnd = ExtOpnd->getOperand(OpIdx); | |||
| 4393 | if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) { | |||
| 4394 | LLVM_DEBUG(dbgs() << "Statically extend\n")do { } while (false); | |||
| 4395 | unsigned BitWidth = Ext->getType()->getIntegerBitWidth(); | |||
| 4396 | APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth) | |||
| 4397 | : Cst->getValue().zext(BitWidth); | |||
| 4398 | TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal)); | |||
| 4399 | continue; | |||
| 4400 | } | |||
| 4401 | // UndefValue are typed, so we have to statically sign extend them. | |||
| 4402 | if (isa<UndefValue>(Opnd)) { | |||
| 4403 | LLVM_DEBUG(dbgs() << "Statically extend\n")do { } while (false); | |||
| 4404 | TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType())); | |||
| 4405 | continue; | |||
| 4406 | } | |||
| 4407 | ||||
| 4408 | // Otherwise we have to explicitly sign extend the operand. | |||
| 4409 | // Check if Ext was reused to extend an operand. | |||
| 4410 | if (!ExtForOpnd) { | |||
| 4411 | // If yes, create a new one. | |||
| 4412 | LLVM_DEBUG(dbgs() << "More operands to ext\n")do { } while (false); | |||
| 4413 | Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType()) | |||
| 4414 | : TPT.createZExt(Ext, Opnd, Ext->getType()); | |||
| 4415 | if (!isa<Instruction>(ValForExtOpnd)) { | |||
| 4416 | TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd); | |||
| 4417 | continue; | |||
| 4418 | } | |||
| 4419 | ExtForOpnd = cast<Instruction>(ValForExtOpnd); | |||
| 4420 | } | |||
| 4421 | if (Exts) | |||
| 4422 | Exts->push_back(ExtForOpnd); | |||
| 4423 | TPT.setOperand(ExtForOpnd, 0, Opnd); | |||
| 4424 | ||||
| 4425 | // Move the sign extension before the insertion point. | |||
| 4426 | TPT.moveBefore(ExtForOpnd, ExtOpnd); | |||
| 4427 | TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd); | |||
| 4428 | CreatedInstsCost += !TLI.isExtFree(ExtForOpnd); | |||
| 4429 | // If more sext are required, new instructions will have to be created. | |||
| 4430 | ExtForOpnd = nullptr; | |||
| 4431 | } | |||
| 4432 | if (ExtForOpnd == Ext) { | |||
| 4433 | LLVM_DEBUG(dbgs() << "Extension is useless now\n")do { } while (false); | |||
| 4434 | TPT.eraseInstruction(Ext); | |||
| 4435 | } | |||
| 4436 | return ExtOpnd; | |||
| 4437 | } | |||
| 4438 | ||||
| 4439 | /// Check whether or not promoting an instruction to a wider type is profitable. | |||
| 4440 | /// \p NewCost gives the cost of extension instructions created by the | |||
| 4441 | /// promotion. | |||
| 4442 | /// \p OldCost gives the cost of extension instructions before the promotion | |||
| 4443 | /// plus the number of instructions that have been | |||
| 4444 | /// matched in the addressing mode the promotion. | |||
| 4445 | /// \p PromotedOperand is the value that has been promoted. | |||
| 4446 | /// \return True if the promotion is profitable, false otherwise. | |||
| 4447 | bool AddressingModeMatcher::isPromotionProfitable( | |||
| 4448 | unsigned NewCost, unsigned OldCost, Value *PromotedOperand) const { | |||
| 4449 | LLVM_DEBUG(dbgs() << "OldCost: " << OldCost << "\tNewCost: " << NewCostdo { } while (false) | |||
| 4450 | << '\n')do { } while (false); | |||
| 4451 | // The cost of the new extensions is greater than the cost of the | |||
| 4452 | // old extension plus what we folded. | |||
| 4453 | // This is not profitable. | |||
| 4454 | if (NewCost > OldCost) | |||
| 4455 | return false; | |||
| 4456 | if (NewCost < OldCost) | |||
| 4457 | return true; | |||
| 4458 | // The promotion is neutral but it may help folding the sign extension in | |||
| 4459 | // loads for instance. | |||
| 4460 | // Check that we did not create an illegal instruction. | |||
| 4461 | return isPromotedInstructionLegal(TLI, DL, PromotedOperand); | |||
| 4462 | } | |||
| 4463 | ||||
| 4464 | /// Given an instruction or constant expr, see if we can fold the operation | |||
| 4465 | /// into the addressing mode. If so, update the addressing mode and return | |||
| 4466 | /// true, otherwise return false without modifying AddrMode. | |||
| 4467 | /// If \p MovedAway is not NULL, it contains the information of whether or | |||
| 4468 | /// not AddrInst has to be folded into the addressing mode on success. | |||
| 4469 | /// If \p MovedAway == true, \p AddrInst will not be part of the addressing | |||
| 4470 | /// because it has been moved away. | |||
| 4471 | /// Thus AddrInst must not be added in the matched instructions. | |||
| 4472 | /// This state can happen when AddrInst is a sext, since it may be moved away. | |||
| 4473 | /// Therefore, AddrInst may not be valid when MovedAway is true and it must | |||
| 4474 | /// not be referenced anymore. | |||
| 4475 | bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode, | |||
| 4476 | unsigned Depth, | |||
| 4477 | bool *MovedAway) { | |||
| 4478 | // Avoid exponential behavior on extremely deep expression trees. | |||
| 4479 | if (Depth >= 5) return false; | |||
| 4480 | ||||
| 4481 | // By default, all matched instructions stay in place. | |||
| 4482 | if (MovedAway) | |||
| 4483 | *MovedAway = false; | |||
| 4484 | ||||
| 4485 | switch (Opcode) { | |||
| 4486 | case Instruction::PtrToInt: | |||
| 4487 | // PtrToInt is always a noop, as we know that the int type is pointer sized. | |||
| 4488 | return matchAddr(AddrInst->getOperand(0), Depth); | |||
| 4489 | case Instruction::IntToPtr: { | |||
| 4490 | auto AS = AddrInst->getType()->getPointerAddressSpace(); | |||
| 4491 | auto PtrTy = MVT::getIntegerVT(DL.getPointerSizeInBits(AS)); | |||
| 4492 | // This inttoptr is a no-op if the integer type is pointer sized. | |||
| 4493 | if (TLI.getValueType(DL, AddrInst->getOperand(0)->getType()) == PtrTy) | |||
| 4494 | return matchAddr(AddrInst->getOperand(0), Depth); | |||
| 4495 | return false; | |||
| 4496 | } | |||
| 4497 | case Instruction::BitCast: | |||
| 4498 | // BitCast is always a noop, and we can handle it as long as it is | |||
| 4499 | // int->int or pointer->pointer (we don't want int<->fp or something). | |||
| 4500 | if (AddrInst->getOperand(0)->getType()->isIntOrPtrTy() && | |||
| 4501 | // Don't touch identity bitcasts. These were probably put here by LSR, | |||
| 4502 | // and we don't want to mess around with them. Assume it knows what it | |||
| 4503 | // is doing. | |||
| 4504 | AddrInst->getOperand(0)->getType() != AddrInst->getType()) | |||
| 4505 | return matchAddr(AddrInst->getOperand(0), Depth); | |||
| 4506 | return false; | |||
| 4507 | case Instruction::AddrSpaceCast: { | |||
| 4508 | unsigned SrcAS | |||
| 4509 | = AddrInst->getOperand(0)->getType()->getPointerAddressSpace(); | |||
| 4510 | unsigned DestAS = AddrInst->getType()->getPointerAddressSpace(); | |||
| 4511 | if (TLI.getTargetMachine().isNoopAddrSpaceCast(SrcAS, DestAS)) | |||
| 4512 | return matchAddr(AddrInst->getOperand(0), Depth); | |||
| 4513 | return false; | |||
| 4514 | } | |||
| 4515 | case Instruction::Add: { | |||
| 4516 | // Check to see if we can merge in the RHS then the LHS. If so, we win. | |||
| 4517 | ExtAddrMode BackupAddrMode = AddrMode; | |||
| 4518 | unsigned OldSize = AddrModeInsts.size(); | |||
| 4519 | // Start a transaction at this point. | |||
| 4520 | // The LHS may match but not the RHS. | |||
| 4521 | // Therefore, we need a higher level restoration point to undo partially | |||
| 4522 | // matched operation. | |||
| 4523 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 4524 | TPT.getRestorationPoint(); | |||
| 4525 | ||||
| 4526 | AddrMode.InBounds = false; | |||
| 4527 | if (matchAddr(AddrInst->getOperand(1), Depth+1) && | |||
| 4528 | matchAddr(AddrInst->getOperand(0), Depth+1)) | |||
| 4529 | return true; | |||
| 4530 | ||||
| 4531 | // Restore the old addr mode info. | |||
| 4532 | AddrMode = BackupAddrMode; | |||
| 4533 | AddrModeInsts.resize(OldSize); | |||
| 4534 | TPT.rollback(LastKnownGood); | |||
| 4535 | ||||
| 4536 | // Otherwise this was over-aggressive. Try merging in the LHS then the RHS. | |||
| 4537 | if (matchAddr(AddrInst->getOperand(0), Depth+1) && | |||
| 4538 | matchAddr(AddrInst->getOperand(1), Depth+1)) | |||
| 4539 | return true; | |||
| 4540 | ||||
| 4541 | // Otherwise we definitely can't merge the ADD in. | |||
| 4542 | AddrMode = BackupAddrMode; | |||
| 4543 | AddrModeInsts.resize(OldSize); | |||
| 4544 | TPT.rollback(LastKnownGood); | |||
| 4545 | break; | |||
| 4546 | } | |||
| 4547 | //case Instruction::Or: | |||
| 4548 | // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD. | |||
| 4549 | //break; | |||
| 4550 | case Instruction::Mul: | |||
| 4551 | case Instruction::Shl: { | |||
| 4552 | // Can only handle X*C and X << C. | |||
| 4553 | AddrMode.InBounds = false; | |||
| 4554 | ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1)); | |||
| 4555 | if (!RHS || RHS->getBitWidth() > 64) | |||
| 4556 | return false; | |||
| 4557 | int64_t Scale = RHS->getSExtValue(); | |||
| 4558 | if (Opcode == Instruction::Shl) | |||
| 4559 | Scale = 1LL << Scale; | |||
| 4560 | ||||
| 4561 | return matchScaledValue(AddrInst->getOperand(0), Scale, Depth); | |||
| 4562 | } | |||
| 4563 | case Instruction::GetElementPtr: { | |||
| 4564 | // Scan the GEP. We check it if it contains constant offsets and at most | |||
| 4565 | // one variable offset. | |||
| 4566 | int VariableOperand = -1; | |||
| 4567 | unsigned VariableScale = 0; | |||
| 4568 | ||||
| 4569 | int64_t ConstantOffset = 0; | |||
| 4570 | gep_type_iterator GTI = gep_type_begin(AddrInst); | |||
| 4571 | for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) { | |||
| 4572 | if (StructType *STy = GTI.getStructTypeOrNull()) { | |||
| 4573 | const StructLayout *SL = DL.getStructLayout(STy); | |||
| 4574 | unsigned Idx = | |||
| 4575 | cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue(); | |||
| 4576 | ConstantOffset += SL->getElementOffset(Idx); | |||
| 4577 | } else { | |||
| 4578 | TypeSize TS = DL.getTypeAllocSize(GTI.getIndexedType()); | |||
| 4579 | if (TS.isNonZero()) { | |||
| 4580 | // The optimisations below currently only work for fixed offsets. | |||
| 4581 | if (TS.isScalable()) | |||
| 4582 | return false; | |||
| 4583 | int64_t TypeSize = TS.getFixedSize(); | |||
| 4584 | if (ConstantInt *CI = | |||
| 4585 | dyn_cast<ConstantInt>(AddrInst->getOperand(i))) { | |||
| 4586 | const APInt &CVal = CI->getValue(); | |||
| 4587 | if (CVal.getMinSignedBits() <= 64) { | |||
| 4588 | ConstantOffset += CVal.getSExtValue() * TypeSize; | |||
| 4589 | continue; | |||
| 4590 | } | |||
| 4591 | } | |||
| 4592 | // We only allow one variable index at the moment. | |||
| 4593 | if (VariableOperand != -1) | |||
| 4594 | return false; | |||
| 4595 | ||||
| 4596 | // Remember the variable index. | |||
| 4597 | VariableOperand = i; | |||
| 4598 | VariableScale = TypeSize; | |||
| 4599 | } | |||
| 4600 | } | |||
| 4601 | } | |||
| 4602 | ||||
| 4603 | // A common case is for the GEP to only do a constant offset. In this case, | |||
| 4604 | // just add it to the disp field and check validity. | |||
| 4605 | if (VariableOperand == -1) { | |||
| 4606 | AddrMode.BaseOffs += ConstantOffset; | |||
| 4607 | if (ConstantOffset == 0 || | |||
| 4608 | TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) { | |||
| 4609 | // Check to see if we can fold the base pointer in too. | |||
| 4610 | if (matchAddr(AddrInst->getOperand(0), Depth+1)) { | |||
| 4611 | if (!cast<GEPOperator>(AddrInst)->isInBounds()) | |||
| 4612 | AddrMode.InBounds = false; | |||
| 4613 | return true; | |||
| 4614 | } | |||
| 4615 | } else if (EnableGEPOffsetSplit && isa<GetElementPtrInst>(AddrInst) && | |||
| 4616 | TLI.shouldConsiderGEPOffsetSplit() && Depth == 0 && | |||
| 4617 | ConstantOffset > 0) { | |||
| 4618 | // Record GEPs with non-zero offsets as candidates for splitting in the | |||
| 4619 | // event that the offset cannot fit into the r+i addressing mode. | |||
| 4620 | // Simple and common case that only one GEP is used in calculating the | |||
| 4621 | // address for the memory access. | |||
| 4622 | Value *Base = AddrInst->getOperand(0); | |||
| 4623 | auto *BaseI = dyn_cast<Instruction>(Base); | |||
| 4624 | auto *GEP = cast<GetElementPtrInst>(AddrInst); | |||
| 4625 | if (isa<Argument>(Base) || isa<GlobalValue>(Base) || | |||
| 4626 | (BaseI && !isa<CastInst>(BaseI) && | |||
| 4627 | !isa<GetElementPtrInst>(BaseI))) { | |||
| 4628 | // Make sure the parent block allows inserting non-PHI instructions | |||
| 4629 | // before the terminator. | |||
| 4630 | BasicBlock *Parent = | |||
| 4631 | BaseI ? BaseI->getParent() : &GEP->getFunction()->getEntryBlock(); | |||
| 4632 | if (!Parent->getTerminator()->isEHPad()) | |||
| 4633 | LargeOffsetGEP = std::make_pair(GEP, ConstantOffset); | |||
| 4634 | } | |||
| 4635 | } | |||
| 4636 | AddrMode.BaseOffs -= ConstantOffset; | |||
| 4637 | return false; | |||
| 4638 | } | |||
| 4639 | ||||
| 4640 | // Save the valid addressing mode in case we can't match. | |||
| 4641 | ExtAddrMode BackupAddrMode = AddrMode; | |||
| 4642 | unsigned OldSize = AddrModeInsts.size(); | |||
| 4643 | ||||
| 4644 | // See if the scale and offset amount is valid for this target. | |||
| 4645 | AddrMode.BaseOffs += ConstantOffset; | |||
| 4646 | if (!cast<GEPOperator>(AddrInst)->isInBounds()) | |||
| 4647 | AddrMode.InBounds = false; | |||
| 4648 | ||||
| 4649 | // Match the base operand of the GEP. | |||
| 4650 | if (!matchAddr(AddrInst->getOperand(0), Depth+1)) { | |||
| 4651 | // If it couldn't be matched, just stuff the value in a register. | |||
| 4652 | if (AddrMode.HasBaseReg) { | |||
| 4653 | AddrMode = BackupAddrMode; | |||
| 4654 | AddrModeInsts.resize(OldSize); | |||
| 4655 | return false; | |||
| 4656 | } | |||
| 4657 | AddrMode.HasBaseReg = true; | |||
| 4658 | AddrMode.BaseReg = AddrInst->getOperand(0); | |||
| 4659 | } | |||
| 4660 | ||||
| 4661 | // Match the remaining variable portion of the GEP. | |||
| 4662 | if (!matchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale, | |||
| 4663 | Depth)) { | |||
| 4664 | // If it couldn't be matched, try stuffing the base into a register | |||
| 4665 | // instead of matching it, and retrying the match of the scale. | |||
| 4666 | AddrMode = BackupAddrMode; | |||
| 4667 | AddrModeInsts.resize(OldSize); | |||
| 4668 | if (AddrMode.HasBaseReg) | |||
| 4669 | return false; | |||
| 4670 | AddrMode.HasBaseReg = true; | |||
| 4671 | AddrMode.BaseReg = AddrInst->getOperand(0); | |||
| 4672 | AddrMode.BaseOffs += ConstantOffset; | |||
| 4673 | if (!matchScaledValue(AddrInst->getOperand(VariableOperand), | |||
| 4674 | VariableScale, Depth)) { | |||
| 4675 | // If even that didn't work, bail. | |||
| 4676 | AddrMode = BackupAddrMode; | |||
| 4677 | AddrModeInsts.resize(OldSize); | |||
| 4678 | return false; | |||
| 4679 | } | |||
| 4680 | } | |||
| 4681 | ||||
| 4682 | return true; | |||
| 4683 | } | |||
| 4684 | case Instruction::SExt: | |||
| 4685 | case Instruction::ZExt: { | |||
| 4686 | Instruction *Ext = dyn_cast<Instruction>(AddrInst); | |||
| 4687 | if (!Ext) | |||
| 4688 | return false; | |||
| 4689 | ||||
| 4690 | // Try to move this ext out of the way of the addressing mode. | |||
| 4691 | // Ask for a method for doing so. | |||
| 4692 | TypePromotionHelper::Action TPH = | |||
| 4693 | TypePromotionHelper::getAction(Ext, InsertedInsts, TLI, PromotedInsts); | |||
| 4694 | if (!TPH) | |||
| 4695 | return false; | |||
| 4696 | ||||
| 4697 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 4698 | TPT.getRestorationPoint(); | |||
| 4699 | unsigned CreatedInstsCost = 0; | |||
| 4700 | unsigned ExtCost = !TLI.isExtFree(Ext); | |||
| 4701 | Value *PromotedOperand = | |||
| 4702 | TPH(Ext, TPT, PromotedInsts, CreatedInstsCost, nullptr, nullptr, TLI); | |||
| 4703 | // SExt has been moved away. | |||
| 4704 | // Thus either it will be rematched later in the recursive calls or it is | |||
| 4705 | // gone. Anyway, we must not fold it into the addressing mode at this point. | |||
| 4706 | // E.g., | |||
| 4707 | // op = add opnd, 1 | |||
| 4708 | // idx = ext op | |||
| 4709 | // addr = gep base, idx | |||
| 4710 | // is now: | |||
| 4711 | // promotedOpnd = ext opnd <- no match here | |||
| 4712 | // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls) | |||
| 4713 | // addr = gep base, op <- match | |||
| 4714 | if (MovedAway) | |||
| 4715 | *MovedAway = true; | |||
| 4716 | ||||
| 4717 | assert(PromotedOperand &&((void)0) | |||
| 4718 | "TypePromotionHelper should have filtered out those cases")((void)0); | |||
| 4719 | ||||
| 4720 | ExtAddrMode BackupAddrMode = AddrMode; | |||
| 4721 | unsigned OldSize = AddrModeInsts.size(); | |||
| 4722 | ||||
| 4723 | if (!matchAddr(PromotedOperand, Depth) || | |||
| 4724 | // The total of the new cost is equal to the cost of the created | |||
| 4725 | // instructions. | |||
| 4726 | // The total of the old cost is equal to the cost of the extension plus | |||
| 4727 | // what we have saved in the addressing mode. | |||
| 4728 | !isPromotionProfitable(CreatedInstsCost, | |||
| 4729 | ExtCost + (AddrModeInsts.size() - OldSize), | |||
| 4730 | PromotedOperand)) { | |||
| 4731 | AddrMode = BackupAddrMode; | |||
| 4732 | AddrModeInsts.resize(OldSize); | |||
| 4733 | LLVM_DEBUG(dbgs() << "Sign extension does not pay off: rollback\n")do { } while (false); | |||
| 4734 | TPT.rollback(LastKnownGood); | |||
| 4735 | return false; | |||
| 4736 | } | |||
| 4737 | return true; | |||
| 4738 | } | |||
| 4739 | } | |||
| 4740 | return false; | |||
| 4741 | } | |||
| 4742 | ||||
| 4743 | /// If we can, try to add the value of 'Addr' into the current addressing mode. | |||
| 4744 | /// If Addr can't be added to AddrMode this returns false and leaves AddrMode | |||
| 4745 | /// unmodified. This assumes that Addr is either a pointer type or intptr_t | |||
| 4746 | /// for the target. | |||
| 4747 | /// | |||
| 4748 | bool AddressingModeMatcher::matchAddr(Value *Addr, unsigned Depth) { | |||
| 4749 | // Start a transaction at this point that we will rollback if the matching | |||
| 4750 | // fails. | |||
| 4751 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 4752 | TPT.getRestorationPoint(); | |||
| 4753 | if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) { | |||
| 4754 | if (CI->getValue().isSignedIntN(64)) { | |||
| 4755 | // Fold in immediates if legal for the target. | |||
| 4756 | AddrMode.BaseOffs += CI->getSExtValue(); | |||
| 4757 | if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) | |||
| 4758 | return true; | |||
| 4759 | AddrMode.BaseOffs -= CI->getSExtValue(); | |||
| 4760 | } | |||
| 4761 | } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) { | |||
| 4762 | // If this is a global variable, try to fold it into the addressing mode. | |||
| 4763 | if (!AddrMode.BaseGV) { | |||
| 4764 | AddrMode.BaseGV = GV; | |||
| 4765 | if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) | |||
| 4766 | return true; | |||
| 4767 | AddrMode.BaseGV = nullptr; | |||
| 4768 | } | |||
| 4769 | } else if (Instruction *I = dyn_cast<Instruction>(Addr)) { | |||
| 4770 | ExtAddrMode BackupAddrMode = AddrMode; | |||
| 4771 | unsigned OldSize = AddrModeInsts.size(); | |||
| 4772 | ||||
| 4773 | // Check to see if it is possible to fold this operation. | |||
| 4774 | bool MovedAway = false; | |||
| 4775 | if (matchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) { | |||
| 4776 | // This instruction may have been moved away. If so, there is nothing | |||
| 4777 | // to check here. | |||
| 4778 | if (MovedAway) | |||
| 4779 | return true; | |||
| 4780 | // Okay, it's possible to fold this. Check to see if it is actually | |||
| 4781 | // *profitable* to do so. We use a simple cost model to avoid increasing | |||
| 4782 | // register pressure too much. | |||
| 4783 | if (I->hasOneUse() || | |||
| 4784 | isProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) { | |||
| 4785 | AddrModeInsts.push_back(I); | |||
| 4786 | return true; | |||
| 4787 | } | |||
| 4788 | ||||
| 4789 | // It isn't profitable to do this, roll back. | |||
| 4790 | //cerr << "NOT FOLDING: " << *I; | |||
| 4791 | AddrMode = BackupAddrMode; | |||
| 4792 | AddrModeInsts.resize(OldSize); | |||
| 4793 | TPT.rollback(LastKnownGood); | |||
| 4794 | } | |||
| 4795 | } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) { | |||
| 4796 | if (matchOperationAddr(CE, CE->getOpcode(), Depth)) | |||
| 4797 | return true; | |||
| 4798 | TPT.rollback(LastKnownGood); | |||
| 4799 | } else if (isa<ConstantPointerNull>(Addr)) { | |||
| 4800 | // Null pointer gets folded without affecting the addressing mode. | |||
| 4801 | return true; | |||
| 4802 | } | |||
| 4803 | ||||
| 4804 | // Worse case, the target should support [reg] addressing modes. :) | |||
| 4805 | if (!AddrMode.HasBaseReg) { | |||
| 4806 | AddrMode.HasBaseReg = true; | |||
| 4807 | AddrMode.BaseReg = Addr; | |||
| 4808 | // Still check for legality in case the target supports [imm] but not [i+r]. | |||
| 4809 | if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) | |||
| 4810 | return true; | |||
| 4811 | AddrMode.HasBaseReg = false; | |||
| 4812 | AddrMode.BaseReg = nullptr; | |||
| 4813 | } | |||
| 4814 | ||||
| 4815 | // If the base register is already taken, see if we can do [r+r]. | |||
| 4816 | if (AddrMode.Scale == 0) { | |||
| 4817 | AddrMode.Scale = 1; | |||
| 4818 | AddrMode.ScaledReg = Addr; | |||
| 4819 | if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) | |||
| 4820 | return true; | |||
| 4821 | AddrMode.Scale = 0; | |||
| 4822 | AddrMode.ScaledReg = nullptr; | |||
| 4823 | } | |||
| 4824 | // Couldn't match. | |||
| 4825 | TPT.rollback(LastKnownGood); | |||
| 4826 | return false; | |||
| 4827 | } | |||
| 4828 | ||||
| 4829 | /// Check to see if all uses of OpVal by the specified inline asm call are due | |||
| 4830 | /// to memory operands. If so, return true, otherwise return false. | |||
| 4831 | static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal, | |||
| 4832 | const TargetLowering &TLI, | |||
| 4833 | const TargetRegisterInfo &TRI) { | |||
| 4834 | const Function *F = CI->getFunction(); | |||
| 4835 | TargetLowering::AsmOperandInfoVector TargetConstraints = | |||
| 4836 | TLI.ParseConstraints(F->getParent()->getDataLayout(), &TRI, *CI); | |||
| 4837 | ||||
| 4838 | for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) { | |||
| 4839 | TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i]; | |||
| 4840 | ||||
| 4841 | // Compute the constraint code and ConstraintType to use. | |||
| 4842 | TLI.ComputeConstraintToUse(OpInfo, SDValue()); | |||
| 4843 | ||||
| 4844 | // If this asm operand is our Value*, and if it isn't an indirect memory | |||
| 4845 | // operand, we can't fold it! | |||
| 4846 | if (OpInfo.CallOperandVal == OpVal && | |||
| 4847 | (OpInfo.ConstraintType != TargetLowering::C_Memory || | |||
| 4848 | !OpInfo.isIndirect)) | |||
| 4849 | return false; | |||
| 4850 | } | |||
| 4851 | ||||
| 4852 | return true; | |||
| 4853 | } | |||
| 4854 | ||||
| 4855 | // Max number of memory uses to look at before aborting the search to conserve | |||
| 4856 | // compile time. | |||
| 4857 | static constexpr int MaxMemoryUsesToScan = 20; | |||
| 4858 | ||||
| 4859 | /// Recursively walk all the uses of I until we find a memory use. | |||
| 4860 | /// If we find an obviously non-foldable instruction, return true. | |||
| 4861 | /// Add the ultimately found memory instructions to MemoryUses. | |||
| 4862 | static bool FindAllMemoryUses( | |||
| 4863 | Instruction *I, | |||
| 4864 | SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses, | |||
| 4865 | SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetLowering &TLI, | |||
| 4866 | const TargetRegisterInfo &TRI, bool OptSize, ProfileSummaryInfo *PSI, | |||
| 4867 | BlockFrequencyInfo *BFI, int SeenInsts = 0) { | |||
| 4868 | // If we already considered this instruction, we're done. | |||
| 4869 | if (!ConsideredInsts.insert(I).second) | |||
| 4870 | return false; | |||
| 4871 | ||||
| 4872 | // If this is an obviously unfoldable instruction, bail out. | |||
| 4873 | if (!MightBeFoldableInst(I)) | |||
| 4874 | return true; | |||
| 4875 | ||||
| 4876 | // Loop over all the uses, recursively processing them. | |||
| 4877 | for (Use &U : I->uses()) { | |||
| 4878 | // Conservatively return true if we're seeing a large number or a deep chain | |||
| 4879 | // of users. This avoids excessive compilation times in pathological cases. | |||
| 4880 | if (SeenInsts++ >= MaxMemoryUsesToScan) | |||
| 4881 | return true; | |||
| 4882 | ||||
| 4883 | Instruction *UserI = cast<Instruction>(U.getUser()); | |||
| 4884 | if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) { | |||
| 4885 | MemoryUses.push_back(std::make_pair(LI, U.getOperandNo())); | |||
| 4886 | continue; | |||
| 4887 | } | |||
| 4888 | ||||
| 4889 | if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) { | |||
| 4890 | unsigned opNo = U.getOperandNo(); | |||
| 4891 | if (opNo != StoreInst::getPointerOperandIndex()) | |||
| 4892 | return true; // Storing addr, not into addr. | |||
| 4893 | MemoryUses.push_back(std::make_pair(SI, opNo)); | |||
| 4894 | continue; | |||
| 4895 | } | |||
| 4896 | ||||
| 4897 | if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(UserI)) { | |||
| 4898 | unsigned opNo = U.getOperandNo(); | |||
| 4899 | if (opNo != AtomicRMWInst::getPointerOperandIndex()) | |||
| 4900 | return true; // Storing addr, not into addr. | |||
| 4901 | MemoryUses.push_back(std::make_pair(RMW, opNo)); | |||
| 4902 | continue; | |||
| 4903 | } | |||
| 4904 | ||||
| 4905 | if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(UserI)) { | |||
| 4906 | unsigned opNo = U.getOperandNo(); | |||
| 4907 | if (opNo != AtomicCmpXchgInst::getPointerOperandIndex()) | |||
| 4908 | return true; // Storing addr, not into addr. | |||
| 4909 | MemoryUses.push_back(std::make_pair(CmpX, opNo)); | |||
| 4910 | continue; | |||
| 4911 | } | |||
| 4912 | ||||
| 4913 | if (CallInst *CI = dyn_cast<CallInst>(UserI)) { | |||
| 4914 | if (CI->hasFnAttr(Attribute::Cold)) { | |||
| 4915 | // If this is a cold call, we can sink the addressing calculation into | |||
| 4916 | // the cold path. See optimizeCallInst | |||
| 4917 | bool OptForSize = OptSize || | |||
| 4918 | llvm::shouldOptimizeForSize(CI->getParent(), PSI, BFI); | |||
| 4919 | if (!OptForSize) | |||
| 4920 | continue; | |||
| 4921 | } | |||
| 4922 | ||||
| 4923 | InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledOperand()); | |||
| 4924 | if (!IA) return true; | |||
| 4925 | ||||
| 4926 | // If this is a memory operand, we're cool, otherwise bail out. | |||
| 4927 | if (!IsOperandAMemoryOperand(CI, IA, I, TLI, TRI)) | |||
| 4928 | return true; | |||
| 4929 | continue; | |||
| 4930 | } | |||
| 4931 | ||||
| 4932 | if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI, TRI, OptSize, | |||
| 4933 | PSI, BFI, SeenInsts)) | |||
| 4934 | return true; | |||
| 4935 | } | |||
| 4936 | ||||
| 4937 | return false; | |||
| 4938 | } | |||
| 4939 | ||||
| 4940 | /// Return true if Val is already known to be live at the use site that we're | |||
| 4941 | /// folding it into. If so, there is no cost to include it in the addressing | |||
| 4942 | /// mode. KnownLive1 and KnownLive2 are two values that we know are live at the | |||
| 4943 | /// instruction already. | |||
| 4944 | bool AddressingModeMatcher::valueAlreadyLiveAtInst(Value *Val,Value *KnownLive1, | |||
| 4945 | Value *KnownLive2) { | |||
| 4946 | // If Val is either of the known-live values, we know it is live! | |||
| 4947 | if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2) | |||
| 4948 | return true; | |||
| 4949 | ||||
| 4950 | // All values other than instructions and arguments (e.g. constants) are live. | |||
| 4951 | if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true; | |||
| 4952 | ||||
| 4953 | // If Val is a constant sized alloca in the entry block, it is live, this is | |||
| 4954 | // true because it is just a reference to the stack/frame pointer, which is | |||
| 4955 | // live for the whole function. | |||
| 4956 | if (AllocaInst *AI = dyn_cast<AllocaInst>(Val)) | |||
| 4957 | if (AI->isStaticAlloca()) | |||
| 4958 | return true; | |||
| 4959 | ||||
| 4960 | // Check to see if this value is already used in the memory instruction's | |||
| 4961 | // block. If so, it's already live into the block at the very least, so we | |||
| 4962 | // can reasonably fold it. | |||
| 4963 | return Val->isUsedInBasicBlock(MemoryInst->getParent()); | |||
| 4964 | } | |||
| 4965 | ||||
| 4966 | /// It is possible for the addressing mode of the machine to fold the specified | |||
| 4967 | /// instruction into a load or store that ultimately uses it. | |||
| 4968 | /// However, the specified instruction has multiple uses. | |||
| 4969 | /// Given this, it may actually increase register pressure to fold it | |||
| 4970 | /// into the load. For example, consider this code: | |||
| 4971 | /// | |||
| 4972 | /// X = ... | |||
| 4973 | /// Y = X+1 | |||
| 4974 | /// use(Y) -> nonload/store | |||
| 4975 | /// Z = Y+1 | |||
| 4976 | /// load Z | |||
| 4977 | /// | |||
| 4978 | /// In this case, Y has multiple uses, and can be folded into the load of Z | |||
| 4979 | /// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to | |||
| 4980 | /// be live at the use(Y) line. If we don't fold Y into load Z, we use one | |||
| 4981 | /// fewer register. Since Y can't be folded into "use(Y)" we don't increase the | |||
| 4982 | /// number of computations either. | |||
| 4983 | /// | |||
| 4984 | /// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If | |||
| 4985 | /// X was live across 'load Z' for other reasons, we actually *would* want to | |||
| 4986 | /// fold the addressing mode in the Z case. This would make Y die earlier. | |||
| 4987 | bool AddressingModeMatcher:: | |||
| 4988 | isProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore, | |||
| 4989 | ExtAddrMode &AMAfter) { | |||
| 4990 | if (IgnoreProfitability) return true; | |||
| 4991 | ||||
| 4992 | // AMBefore is the addressing mode before this instruction was folded into it, | |||
| 4993 | // and AMAfter is the addressing mode after the instruction was folded. Get | |||
| 4994 | // the set of registers referenced by AMAfter and subtract out those | |||
| 4995 | // referenced by AMBefore: this is the set of values which folding in this | |||
| 4996 | // address extends the lifetime of. | |||
| 4997 | // | |||
| 4998 | // Note that there are only two potential values being referenced here, | |||
| 4999 | // BaseReg and ScaleReg (global addresses are always available, as are any | |||
| 5000 | // folded immediates). | |||
| 5001 | Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg; | |||
| 5002 | ||||
| 5003 | // If the BaseReg or ScaledReg was referenced by the previous addrmode, their | |||
| 5004 | // lifetime wasn't extended by adding this instruction. | |||
| 5005 | if (valueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg)) | |||
| 5006 | BaseReg = nullptr; | |||
| 5007 | if (valueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg)) | |||
| 5008 | ScaledReg = nullptr; | |||
| 5009 | ||||
| 5010 | // If folding this instruction (and it's subexprs) didn't extend any live | |||
| 5011 | // ranges, we're ok with it. | |||
| 5012 | if (!BaseReg && !ScaledReg) | |||
| 5013 | return true; | |||
| 5014 | ||||
| 5015 | // If all uses of this instruction can have the address mode sunk into them, | |||
| 5016 | // we can remove the addressing mode and effectively trade one live register | |||
| 5017 | // for another (at worst.) In this context, folding an addressing mode into | |||
| 5018 | // the use is just a particularly nice way of sinking it. | |||
| 5019 | SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses; | |||
| 5020 | SmallPtrSet<Instruction*, 16> ConsideredInsts; | |||
| 5021 | if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI, TRI, OptSize, | |||
| 5022 | PSI, BFI)) | |||
| 5023 | return false; // Has a non-memory, non-foldable use! | |||
| 5024 | ||||
| 5025 | // Now that we know that all uses of this instruction are part of a chain of | |||
| 5026 | // computation involving only operations that could theoretically be folded | |||
| 5027 | // into a memory use, loop over each of these memory operation uses and see | |||
| 5028 | // if they could *actually* fold the instruction. The assumption is that | |||
| 5029 | // addressing modes are cheap and that duplicating the computation involved | |||
| 5030 | // many times is worthwhile, even on a fastpath. For sinking candidates | |||
| 5031 | // (i.e. cold call sites), this serves as a way to prevent excessive code | |||
| 5032 | // growth since most architectures have some reasonable small and fast way to | |||
| 5033 | // compute an effective address. (i.e LEA on x86) | |||
| 5034 | SmallVector<Instruction*, 32> MatchedAddrModeInsts; | |||
| 5035 | for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) { | |||
| 5036 | Instruction *User = MemoryUses[i].first; | |||
| 5037 | unsigned OpNo = MemoryUses[i].second; | |||
| 5038 | ||||
| 5039 | // Get the access type of this use. If the use isn't a pointer, we don't | |||
| 5040 | // know what it accesses. | |||
| 5041 | Value *Address = User->getOperand(OpNo); | |||
| 5042 | PointerType *AddrTy = dyn_cast<PointerType>(Address->getType()); | |||
| 5043 | if (!AddrTy) | |||
| 5044 | return false; | |||
| 5045 | Type *AddressAccessTy = AddrTy->getElementType(); | |||
| 5046 | unsigned AS = AddrTy->getAddressSpace(); | |||
| 5047 | ||||
| 5048 | // Do a match against the root of this address, ignoring profitability. This | |||
| 5049 | // will tell us if the addressing mode for the memory operation will | |||
| 5050 | // *actually* cover the shared instruction. | |||
| 5051 | ExtAddrMode Result; | |||
| 5052 | std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr, | |||
| 5053 | 0); | |||
| 5054 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 5055 | TPT.getRestorationPoint(); | |||
| 5056 | AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, TRI, LI, getDTFn, | |||
| 5057 | AddressAccessTy, AS, MemoryInst, Result, | |||
| 5058 | InsertedInsts, PromotedInsts, TPT, | |||
| 5059 | LargeOffsetGEP, OptSize, PSI, BFI); | |||
| 5060 | Matcher.IgnoreProfitability = true; | |||
| 5061 | bool Success = Matcher.matchAddr(Address, 0); | |||
| 5062 | (void)Success; assert(Success && "Couldn't select *anything*?")((void)0); | |||
| 5063 | ||||
| 5064 | // The match was to check the profitability, the changes made are not | |||
| 5065 | // part of the original matcher. Therefore, they should be dropped | |||
| 5066 | // otherwise the original matcher will not present the right state. | |||
| 5067 | TPT.rollback(LastKnownGood); | |||
| 5068 | ||||
| 5069 | // If the match didn't cover I, then it won't be shared by it. | |||
| 5070 | if (!is_contained(MatchedAddrModeInsts, I)) | |||
| 5071 | return false; | |||
| 5072 | ||||
| 5073 | MatchedAddrModeInsts.clear(); | |||
| 5074 | } | |||
| 5075 | ||||
| 5076 | return true; | |||
| 5077 | } | |||
| 5078 | ||||
| 5079 | /// Return true if the specified values are defined in a | |||
| 5080 | /// different basic block than BB. | |||
| 5081 | static bool IsNonLocalValue(Value *V, BasicBlock *BB) { | |||
| 5082 | if (Instruction *I = dyn_cast<Instruction>(V)) | |||
| 5083 | return I->getParent() != BB; | |||
| 5084 | return false; | |||
| 5085 | } | |||
| 5086 | ||||
| 5087 | /// Sink addressing mode computation immediate before MemoryInst if doing so | |||
| 5088 | /// can be done without increasing register pressure. The need for the | |||
| 5089 | /// register pressure constraint means this can end up being an all or nothing | |||
| 5090 | /// decision for all uses of the same addressing computation. | |||
| 5091 | /// | |||
| 5092 | /// Load and Store Instructions often have addressing modes that can do | |||
| 5093 | /// significant amounts of computation. As such, instruction selection will try | |||
| 5094 | /// to get the load or store to do as much computation as possible for the | |||
| 5095 | /// program. The problem is that isel can only see within a single block. As | |||
| 5096 | /// such, we sink as much legal addressing mode work into the block as possible. | |||
| 5097 | /// | |||
| 5098 | /// This method is used to optimize both load/store and inline asms with memory | |||
| 5099 | /// operands. It's also used to sink addressing computations feeding into cold | |||
| 5100 | /// call sites into their (cold) basic block. | |||
| 5101 | /// | |||
| 5102 | /// The motivation for handling sinking into cold blocks is that doing so can | |||
| 5103 | /// both enable other address mode sinking (by satisfying the register pressure | |||
| 5104 | /// constraint above), and reduce register pressure globally (by removing the | |||
| 5105 | /// addressing mode computation from the fast path entirely.). | |||
| 5106 | bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr, | |||
| 5107 | Type *AccessTy, unsigned AddrSpace) { | |||
| 5108 | Value *Repl = Addr; | |||
| 5109 | ||||
| 5110 | // Try to collapse single-value PHI nodes. This is necessary to undo | |||
| 5111 | // unprofitable PRE transformations. | |||
| 5112 | SmallVector<Value*, 8> worklist; | |||
| 5113 | SmallPtrSet<Value*, 16> Visited; | |||
| 5114 | worklist.push_back(Addr); | |||
| 5115 | ||||
| 5116 | // Use a worklist to iteratively look through PHI and select nodes, and | |||
| 5117 | // ensure that the addressing mode obtained from the non-PHI/select roots of | |||
| 5118 | // the graph are compatible. | |||
| 5119 | bool PhiOrSelectSeen = false; | |||
| 5120 | SmallVector<Instruction*, 16> AddrModeInsts; | |||
| 5121 | const SimplifyQuery SQ(*DL, TLInfo); | |||
| 5122 | AddressingModeCombiner AddrModes(SQ, Addr); | |||
| 5123 | TypePromotionTransaction TPT(RemovedInsts); | |||
| 5124 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 5125 | TPT.getRestorationPoint(); | |||
| 5126 | while (!worklist.empty()) { | |||
| 5127 | Value *V = worklist.back(); | |||
| 5128 | worklist.pop_back(); | |||
| 5129 | ||||
| 5130 | // We allow traversing cyclic Phi nodes. | |||
| 5131 | // In case of success after this loop we ensure that traversing through | |||
| 5132 | // Phi nodes ends up with all cases to compute address of the form | |||
| 5133 | // BaseGV + Base + Scale * Index + Offset | |||
| 5134 | // where Scale and Offset are constans and BaseGV, Base and Index | |||
| 5135 | // are exactly the same Values in all cases. | |||
| 5136 | // It means that BaseGV, Scale and Offset dominate our memory instruction | |||
| 5137 | // and have the same value as they had in address computation represented | |||
| 5138 | // as Phi. So we can safely sink address computation to memory instruction. | |||
| 5139 | if (!Visited.insert(V).second) | |||
| 5140 | continue; | |||
| 5141 | ||||
| 5142 | // For a PHI node, push all of its incoming values. | |||
| 5143 | if (PHINode *P = dyn_cast<PHINode>(V)) { | |||
| 5144 | append_range(worklist, P->incoming_values()); | |||
| 5145 | PhiOrSelectSeen = true; | |||
| 5146 | continue; | |||
| 5147 | } | |||
| 5148 | // Similar for select. | |||
| 5149 | if (SelectInst *SI = dyn_cast<SelectInst>(V)) { | |||
| 5150 | worklist.push_back(SI->getFalseValue()); | |||
| 5151 | worklist.push_back(SI->getTrueValue()); | |||
| 5152 | PhiOrSelectSeen = true; | |||
| 5153 | continue; | |||
| 5154 | } | |||
| 5155 | ||||
| 5156 | // For non-PHIs, determine the addressing mode being computed. Note that | |||
| 5157 | // the result may differ depending on what other uses our candidate | |||
| 5158 | // addressing instructions might have. | |||
| 5159 | AddrModeInsts.clear(); | |||
| 5160 | std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr, | |||
| 5161 | 0); | |||
| 5162 | // Defer the query (and possible computation of) the dom tree to point of | |||
| 5163 | // actual use. It's expected that most address matches don't actually need | |||
| 5164 | // the domtree. | |||
| 5165 | auto getDTFn = [MemoryInst, this]() -> const DominatorTree & { | |||
| 5166 | Function *F = MemoryInst->getParent()->getParent(); | |||
| 5167 | return this->getDT(*F); | |||
| 5168 | }; | |||
| 5169 | ExtAddrMode NewAddrMode = AddressingModeMatcher::Match( | |||
| 5170 | V, AccessTy, AddrSpace, MemoryInst, AddrModeInsts, *TLI, *LI, getDTFn, | |||
| 5171 | *TRI, InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI, | |||
| 5172 | BFI.get()); | |||
| 5173 | ||||
| 5174 | GetElementPtrInst *GEP = LargeOffsetGEP.first; | |||
| 5175 | if (GEP && !NewGEPBases.count(GEP)) { | |||
| 5176 | // If splitting the underlying data structure can reduce the offset of a | |||
| 5177 | // GEP, collect the GEP. Skip the GEPs that are the new bases of | |||
| 5178 | // previously split data structures. | |||
| 5179 | LargeOffsetGEPMap[GEP->getPointerOperand()].push_back(LargeOffsetGEP); | |||
| 5180 | if (LargeOffsetGEPID.find(GEP) == LargeOffsetGEPID.end()) | |||
| 5181 | LargeOffsetGEPID[GEP] = LargeOffsetGEPID.size(); | |||
| 5182 | } | |||
| 5183 | ||||
| 5184 | NewAddrMode.OriginalValue = V; | |||
| 5185 | if (!AddrModes.addNewAddrMode(NewAddrMode)) | |||
| 5186 | break; | |||
| 5187 | } | |||
| 5188 | ||||
| 5189 | // Try to combine the AddrModes we've collected. If we couldn't collect any, | |||
| 5190 | // or we have multiple but either couldn't combine them or combining them | |||
| 5191 | // wouldn't do anything useful, bail out now. | |||
| 5192 | if (!AddrModes.combineAddrModes()) { | |||
| 5193 | TPT.rollback(LastKnownGood); | |||
| 5194 | return false; | |||
| 5195 | } | |||
| 5196 | bool Modified = TPT.commit(); | |||
| 5197 | ||||
| 5198 | // Get the combined AddrMode (or the only AddrMode, if we only had one). | |||
| 5199 | ExtAddrMode AddrMode = AddrModes.getAddrMode(); | |||
| 5200 | ||||
| 5201 | // If all the instructions matched are already in this BB, don't do anything. | |||
| 5202 | // If we saw a Phi node then it is not local definitely, and if we saw a select | |||
| 5203 | // then we want to push the address calculation past it even if it's already | |||
| 5204 | // in this BB. | |||
| 5205 | if (!PhiOrSelectSeen && none_of(AddrModeInsts, [&](Value *V) { | |||
| 5206 | return IsNonLocalValue(V, MemoryInst->getParent()); | |||
| 5207 | })) { | |||
| 5208 | LLVM_DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrModedo { } while (false) | |||
| 5209 | << "\n")do { } while (false); | |||
| 5210 | return Modified; | |||
| 5211 | } | |||
| 5212 | ||||
| 5213 | // Insert this computation right after this user. Since our caller is | |||
| 5214 | // scanning from the top of the BB to the bottom, reuse of the expr are | |||
| 5215 | // guaranteed to happen later. | |||
| 5216 | IRBuilder<> Builder(MemoryInst); | |||
| 5217 | ||||
| 5218 | // Now that we determined the addressing expression we want to use and know | |||
| 5219 | // that we have to sink it into this block. Check to see if we have already | |||
| 5220 | // done this for some other load/store instr in this block. If so, reuse | |||
| 5221 | // the computation. Before attempting reuse, check if the address is valid | |||
| 5222 | // as it may have been erased. | |||
| 5223 | ||||
| 5224 | WeakTrackingVH SunkAddrVH = SunkAddrs[Addr]; | |||
| 5225 | ||||
| 5226 | Value * SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr; | |||
| 5227 | if (SunkAddr) { | |||
| 5228 | LLVM_DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrModedo { } while (false) | |||
| 5229 | << " for " << *MemoryInst << "\n")do { } while (false); | |||
| 5230 | if (SunkAddr->getType() != Addr->getType()) | |||
| 5231 | SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType()); | |||
| 5232 | } else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() && | |||
| 5233 | SubtargetInfo->addrSinkUsingGEPs())) { | |||
| 5234 | // By default, we use the GEP-based method when AA is used later. This | |||
| 5235 | // prevents new inttoptr/ptrtoint pairs from degrading AA capabilities. | |||
| 5236 | LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { } while (false) | |||
| 5237 | << " for " << *MemoryInst << "\n")do { } while (false); | |||
| 5238 | Type *IntPtrTy = DL->getIntPtrType(Addr->getType()); | |||
| 5239 | Value *ResultPtr = nullptr, *ResultIndex = nullptr; | |||
| 5240 | ||||
| 5241 | // First, find the pointer. | |||
| 5242 | if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) { | |||
| 5243 | ResultPtr = AddrMode.BaseReg; | |||
| 5244 | AddrMode.BaseReg = nullptr; | |||
| 5245 | } | |||
| 5246 | ||||
| 5247 | if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) { | |||
| 5248 | // We can't add more than one pointer together, nor can we scale a | |||
| 5249 | // pointer (both of which seem meaningless). | |||
| 5250 | if (ResultPtr || AddrMode.Scale != 1) | |||
| 5251 | return Modified; | |||
| 5252 | ||||
| 5253 | ResultPtr = AddrMode.ScaledReg; | |||
| 5254 | AddrMode.Scale = 0; | |||
| 5255 | } | |||
| 5256 | ||||
| 5257 | // It is only safe to sign extend the BaseReg if we know that the math | |||
| 5258 | // required to create it did not overflow before we extend it. Since | |||
| 5259 | // the original IR value was tossed in favor of a constant back when | |||
| 5260 | // the AddrMode was created we need to bail out gracefully if widths | |||
| 5261 | // do not match instead of extending it. | |||
| 5262 | // | |||
| 5263 | // (See below for code to add the scale.) | |||
| 5264 | if (AddrMode.Scale) { | |||
| 5265 | Type *ScaledRegTy = AddrMode.ScaledReg->getType(); | |||
| 5266 | if (cast<IntegerType>(IntPtrTy)->getBitWidth() > | |||
| 5267 | cast<IntegerType>(ScaledRegTy)->getBitWidth()) | |||
| 5268 | return Modified; | |||
| 5269 | } | |||
| 5270 | ||||
| 5271 | if (AddrMode.BaseGV) { | |||
| 5272 | if (ResultPtr) | |||
| 5273 | return Modified; | |||
| 5274 | ||||
| 5275 | ResultPtr = AddrMode.BaseGV; | |||
| 5276 | } | |||
| 5277 | ||||
| 5278 | // If the real base value actually came from an inttoptr, then the matcher | |||
| 5279 | // will look through it and provide only the integer value. In that case, | |||
| 5280 | // use it here. | |||
| 5281 | if (!DL->isNonIntegralPointerType(Addr->getType())) { | |||
| 5282 | if (!ResultPtr && AddrMode.BaseReg) { | |||
| 5283 | ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(), | |||
| 5284 | "sunkaddr"); | |||
| 5285 | AddrMode.BaseReg = nullptr; | |||
| 5286 | } else if (!ResultPtr && AddrMode.Scale == 1) { | |||
| 5287 | ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(), | |||
| 5288 | "sunkaddr"); | |||
| 5289 | AddrMode.Scale = 0; | |||
| 5290 | } | |||
| 5291 | } | |||
| 5292 | ||||
| 5293 | if (!ResultPtr && | |||
| 5294 | !AddrMode.BaseReg && !AddrMode.Scale && !AddrMode.BaseOffs) { | |||
| 5295 | SunkAddr = Constant::getNullValue(Addr->getType()); | |||
| 5296 | } else if (!ResultPtr) { | |||
| 5297 | return Modified; | |||
| 5298 | } else { | |||
| 5299 | Type *I8PtrTy = | |||
| 5300 | Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace()); | |||
| 5301 | Type *I8Ty = Builder.getInt8Ty(); | |||
| 5302 | ||||
| 5303 | // Start with the base register. Do this first so that subsequent address | |||
| 5304 | // matching finds it last, which will prevent it from trying to match it | |||
| 5305 | // as the scaled value in case it happens to be a mul. That would be | |||
| 5306 | // problematic if we've sunk a different mul for the scale, because then | |||
| 5307 | // we'd end up sinking both muls. | |||
| 5308 | if (AddrMode.BaseReg) { | |||
| 5309 | Value *V = AddrMode.BaseReg; | |||
| 5310 | if (V->getType() != IntPtrTy) | |||
| 5311 | V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr"); | |||
| 5312 | ||||
| 5313 | ResultIndex = V; | |||
| 5314 | } | |||
| 5315 | ||||
| 5316 | // Add the scale value. | |||
| 5317 | if (AddrMode.Scale) { | |||
| 5318 | Value *V = AddrMode.ScaledReg; | |||
| 5319 | if (V->getType() == IntPtrTy) { | |||
| 5320 | // done. | |||
| 5321 | } else { | |||
| 5322 | assert(cast<IntegerType>(IntPtrTy)->getBitWidth() <((void)0) | |||
| 5323 | cast<IntegerType>(V->getType())->getBitWidth() &&((void)0) | |||
| 5324 | "We can't transform if ScaledReg is too narrow")((void)0); | |||
| 5325 | V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr"); | |||
| 5326 | } | |||
| 5327 | ||||
| 5328 | if (AddrMode.Scale != 1) | |||
| 5329 | V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale), | |||
| 5330 | "sunkaddr"); | |||
| 5331 | if (ResultIndex) | |||
| 5332 | ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr"); | |||
| 5333 | else | |||
| 5334 | ResultIndex = V; | |||
| 5335 | } | |||
| 5336 | ||||
| 5337 | // Add in the Base Offset if present. | |||
| 5338 | if (AddrMode.BaseOffs) { | |||
| 5339 | Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs); | |||
| 5340 | if (ResultIndex) { | |||
| 5341 | // We need to add this separately from the scale above to help with | |||
| 5342 | // SDAG consecutive load/store merging. | |||
| 5343 | if (ResultPtr->getType() != I8PtrTy) | |||
| 5344 | ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy); | |||
| 5345 | ResultPtr = | |||
| 5346 | AddrMode.InBounds | |||
| 5347 | ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex, | |||
| 5348 | "sunkaddr") | |||
| 5349 | : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr"); | |||
| 5350 | } | |||
| 5351 | ||||
| 5352 | ResultIndex = V; | |||
| 5353 | } | |||
| 5354 | ||||
| 5355 | if (!ResultIndex) { | |||
| 5356 | SunkAddr = ResultPtr; | |||
| 5357 | } else { | |||
| 5358 | if (ResultPtr->getType() != I8PtrTy) | |||
| 5359 | ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy); | |||
| 5360 | SunkAddr = | |||
| 5361 | AddrMode.InBounds | |||
| 5362 | ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex, | |||
| 5363 | "sunkaddr") | |||
| 5364 | : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr"); | |||
| 5365 | } | |||
| 5366 | ||||
| 5367 | if (SunkAddr->getType() != Addr->getType()) | |||
| 5368 | SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType()); | |||
| 5369 | } | |||
| 5370 | } else { | |||
| 5371 | // We'd require a ptrtoint/inttoptr down the line, which we can't do for | |||
| 5372 | // non-integral pointers, so in that case bail out now. | |||
| 5373 | Type *BaseTy = AddrMode.BaseReg ? AddrMode.BaseReg->getType() : nullptr; | |||
| 5374 | Type *ScaleTy = AddrMode.Scale ? AddrMode.ScaledReg->getType() : nullptr; | |||
| 5375 | PointerType *BasePtrTy = dyn_cast_or_null<PointerType>(BaseTy); | |||
| 5376 | PointerType *ScalePtrTy = dyn_cast_or_null<PointerType>(ScaleTy); | |||
| 5377 | if (DL->isNonIntegralPointerType(Addr->getType()) || | |||
| 5378 | (BasePtrTy && DL->isNonIntegralPointerType(BasePtrTy)) || | |||
| 5379 | (ScalePtrTy && DL->isNonIntegralPointerType(ScalePtrTy)) || | |||
| 5380 | (AddrMode.BaseGV && | |||
| 5381 | DL->isNonIntegralPointerType(AddrMode.BaseGV->getType()))) | |||
| 5382 | return Modified; | |||
| 5383 | ||||
| 5384 | LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { } while (false) | |||
| 5385 | << " for " << *MemoryInst << "\n")do { } while (false); | |||
| 5386 | Type *IntPtrTy = DL->getIntPtrType(Addr->getType()); | |||
| 5387 | Value *Result = nullptr; | |||
| 5388 | ||||
| 5389 | // Start with the base register. Do this first so that subsequent address | |||
| 5390 | // matching finds it last, which will prevent it from trying to match it | |||
| 5391 | // as the scaled value in case it happens to be a mul. That would be | |||
| 5392 | // problematic if we've sunk a different mul for the scale, because then | |||
| 5393 | // we'd end up sinking both muls. | |||
| 5394 | if (AddrMode.BaseReg) { | |||
| 5395 | Value *V = AddrMode.BaseReg; | |||
| 5396 | if (V->getType()->isPointerTy()) | |||
| 5397 | V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr"); | |||
| 5398 | if (V->getType() != IntPtrTy) | |||
| 5399 | V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr"); | |||
| 5400 | Result = V; | |||
| 5401 | } | |||
| 5402 | ||||
| 5403 | // Add the scale value. | |||
| 5404 | if (AddrMode.Scale) { | |||
| 5405 | Value *V = AddrMode.ScaledReg; | |||
| 5406 | if (V->getType() == IntPtrTy) { | |||
| 5407 | // done. | |||
| 5408 | } else if (V->getType()->isPointerTy()) { | |||
| 5409 | V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr"); | |||
| 5410 | } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() < | |||
| 5411 | cast<IntegerType>(V->getType())->getBitWidth()) { | |||
| 5412 | V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr"); | |||
| 5413 | } else { | |||
| 5414 | // It is only safe to sign extend the BaseReg if we know that the math | |||
| 5415 | // required to create it did not overflow before we extend it. Since | |||
| 5416 | // the original IR value was tossed in favor of a constant back when | |||
| 5417 | // the AddrMode was created we need to bail out gracefully if widths | |||
| 5418 | // do not match instead of extending it. | |||
| 5419 | Instruction *I = dyn_cast_or_null<Instruction>(Result); | |||
| 5420 | if (I && (Result != AddrMode.BaseReg)) | |||
| 5421 | I->eraseFromParent(); | |||
| 5422 | return Modified; | |||
| 5423 | } | |||
| 5424 | if (AddrMode.Scale != 1) | |||
| 5425 | V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale), | |||
| 5426 | "sunkaddr"); | |||
| 5427 | if (Result) | |||
| 5428 | Result = Builder.CreateAdd(Result, V, "sunkaddr"); | |||
| 5429 | else | |||
| 5430 | Result = V; | |||
| 5431 | } | |||
| 5432 | ||||
| 5433 | // Add in the BaseGV if present. | |||
| 5434 | if (AddrMode.BaseGV) { | |||
| 5435 | Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr"); | |||
| 5436 | if (Result) | |||
| 5437 | Result = Builder.CreateAdd(Result, V, "sunkaddr"); | |||
| 5438 | else | |||
| 5439 | Result = V; | |||
| 5440 | } | |||
| 5441 | ||||
| 5442 | // Add in the Base Offset if present. | |||
| 5443 | if (AddrMode.BaseOffs) { | |||
| 5444 | Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs); | |||
| 5445 | if (Result) | |||
| 5446 | Result = Builder.CreateAdd(Result, V, "sunkaddr"); | |||
| 5447 | else | |||
| 5448 | Result = V; | |||
| 5449 | } | |||
| 5450 | ||||
| 5451 | if (!Result) | |||
| 5452 | SunkAddr = Constant::getNullValue(Addr->getType()); | |||
| 5453 | else | |||
| 5454 | SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr"); | |||
| 5455 | } | |||
| 5456 | ||||
| 5457 | MemoryInst->replaceUsesOfWith(Repl, SunkAddr); | |||
| 5458 | // Store the newly computed address into the cache. In the case we reused a | |||
| 5459 | // value, this should be idempotent. | |||
| 5460 | SunkAddrs[Addr] = WeakTrackingVH(SunkAddr); | |||
| 5461 | ||||
| 5462 | // If we have no uses, recursively delete the value and all dead instructions | |||
| 5463 | // using it. | |||
| 5464 | if (Repl->use_empty()) { | |||
| 5465 | resetIteratorIfInvalidatedWhileCalling(CurInstIterator->getParent(), [&]() { | |||
| 5466 | RecursivelyDeleteTriviallyDeadInstructions( | |||
| 5467 | Repl, TLInfo, nullptr, | |||
| 5468 | [&](Value *V) { removeAllAssertingVHReferences(V); }); | |||
| 5469 | }); | |||
| 5470 | } | |||
| 5471 | ++NumMemoryInsts; | |||
| 5472 | return true; | |||
| 5473 | } | |||
| 5474 | ||||
| 5475 | /// Rewrite GEP input to gather/scatter to enable SelectionDAGBuilder to find | |||
| 5476 | /// a uniform base to use for ISD::MGATHER/MSCATTER. SelectionDAGBuilder can | |||
| 5477 | /// only handle a 2 operand GEP in the same basic block or a splat constant | |||
| 5478 | /// vector. The 2 operands to the GEP must have a scalar pointer and a vector | |||
| 5479 | /// index. | |||
| 5480 | /// | |||
| 5481 | /// If the existing GEP has a vector base pointer that is splat, we can look | |||
| 5482 | /// through the splat to find the scalar pointer. If we can't find a scalar | |||
| 5483 | /// pointer there's nothing we can do. | |||
| 5484 | /// | |||
| 5485 | /// If we have a GEP with more than 2 indices where the middle indices are all | |||
| 5486 | /// zeroes, we can replace it with 2 GEPs where the second has 2 operands. | |||
| 5487 | /// | |||
| 5488 | /// If the final index isn't a vector or is a splat, we can emit a scalar GEP | |||
| 5489 | /// followed by a GEP with an all zeroes vector index. This will enable | |||
| 5490 | /// SelectionDAGBuilder to use the scalar GEP as the uniform base and have a | |||
| 5491 | /// zero index. | |||
| 5492 | bool CodeGenPrepare::optimizeGatherScatterInst(Instruction *MemoryInst, | |||
| 5493 | Value *Ptr) { | |||
| 5494 | Value *NewAddr; | |||
| 5495 | ||||
| 5496 | if (const auto *GEP = dyn_cast<GetElementPtrInst>(Ptr)) { | |||
| 5497 | // Don't optimize GEPs that don't have indices. | |||
| 5498 | if (!GEP->hasIndices()) | |||
| 5499 | return false; | |||
| 5500 | ||||
| 5501 | // If the GEP and the gather/scatter aren't in the same BB, don't optimize. | |||
| 5502 | // FIXME: We should support this by sinking the GEP. | |||
| 5503 | if (MemoryInst->getParent() != GEP->getParent()) | |||
| 5504 | return false; | |||
| 5505 | ||||
| 5506 | SmallVector<Value *, 2> Ops(GEP->operands()); | |||
| 5507 | ||||
| 5508 | bool RewriteGEP = false; | |||
| 5509 | ||||
| 5510 | if (Ops[0]->getType()->isVectorTy()) { | |||
| 5511 | Ops[0] = getSplatValue(Ops[0]); | |||
| 5512 | if (!Ops[0]) | |||
| 5513 | return false; | |||
| 5514 | RewriteGEP = true; | |||
| 5515 | } | |||
| 5516 | ||||
| 5517 | unsigned FinalIndex = Ops.size() - 1; | |||
| 5518 | ||||
| 5519 | // Ensure all but the last index is 0. | |||
| 5520 | // FIXME: This isn't strictly required. All that's required is that they are | |||
| 5521 | // all scalars or splats. | |||
| 5522 | for (unsigned i = 1; i < FinalIndex; ++i) { | |||
| 5523 | auto *C = dyn_cast<Constant>(Ops[i]); | |||
| 5524 | if (!C) | |||
| 5525 | return false; | |||
| 5526 | if (isa<VectorType>(C->getType())) | |||
| 5527 | C = C->getSplatValue(); | |||
| 5528 | auto *CI = dyn_cast_or_null<ConstantInt>(C); | |||
| 5529 | if (!CI || !CI->isZero()) | |||
| 5530 | return false; | |||
| 5531 | // Scalarize the index if needed. | |||
| 5532 | Ops[i] = CI; | |||
| 5533 | } | |||
| 5534 | ||||
| 5535 | // Try to scalarize the final index. | |||
| 5536 | if (Ops[FinalIndex]->getType()->isVectorTy()) { | |||
| 5537 | if (Value *V = getSplatValue(Ops[FinalIndex])) { | |||
| 5538 | auto *C = dyn_cast<ConstantInt>(V); | |||
| 5539 | // Don't scalarize all zeros vector. | |||
| 5540 | if (!C || !C->isZero()) { | |||
| 5541 | Ops[FinalIndex] = V; | |||
| 5542 | RewriteGEP = true; | |||
| 5543 | } | |||
| 5544 | } | |||
| 5545 | } | |||
| 5546 | ||||
| 5547 | // If we made any changes or the we have extra operands, we need to generate | |||
| 5548 | // new instructions. | |||
| 5549 | if (!RewriteGEP && Ops.size() == 2) | |||
| 5550 | return false; | |||
| 5551 | ||||
| 5552 | auto NumElts = cast<VectorType>(Ptr->getType())->getElementCount(); | |||
| 5553 | ||||
| 5554 | IRBuilder<> Builder(MemoryInst); | |||
| 5555 | ||||
| 5556 | Type *SourceTy = GEP->getSourceElementType(); | |||
| 5557 | Type *ScalarIndexTy = DL->getIndexType(Ops[0]->getType()->getScalarType()); | |||
| 5558 | ||||
| 5559 | // If the final index isn't a vector, emit a scalar GEP containing all ops | |||
| 5560 | // and a vector GEP with all zeroes final index. | |||
| 5561 | if (!Ops[FinalIndex]->getType()->isVectorTy()) { | |||
| 5562 | NewAddr = Builder.CreateGEP(SourceTy, Ops[0], | |||
| 5563 | makeArrayRef(Ops).drop_front()); | |||
| 5564 | auto *IndexTy = VectorType::get(ScalarIndexTy, NumElts); | |||
| 5565 | auto *SecondTy = GetElementPtrInst::getIndexedType( | |||
| 5566 | SourceTy, makeArrayRef(Ops).drop_front()); | |||
| 5567 | NewAddr = | |||
| 5568 | Builder.CreateGEP(SecondTy, NewAddr, Constant::getNullValue(IndexTy)); | |||
| 5569 | } else { | |||
| 5570 | Value *Base = Ops[0]; | |||
| 5571 | Value *Index = Ops[FinalIndex]; | |||
| 5572 | ||||
| 5573 | // Create a scalar GEP if there are more than 2 operands. | |||
| 5574 | if (Ops.size() != 2) { | |||
| 5575 | // Replace the last index with 0. | |||
| 5576 | Ops[FinalIndex] = Constant::getNullValue(ScalarIndexTy); | |||
| 5577 | Base = Builder.CreateGEP(SourceTy, Base, | |||
| 5578 | makeArrayRef(Ops).drop_front()); | |||
| 5579 | SourceTy = GetElementPtrInst::getIndexedType( | |||
| 5580 | SourceTy, makeArrayRef(Ops).drop_front()); | |||
| 5581 | } | |||
| 5582 | ||||
| 5583 | // Now create the GEP with scalar pointer and vector index. | |||
| 5584 | NewAddr = Builder.CreateGEP(SourceTy, Base, Index); | |||
| 5585 | } | |||
| 5586 | } else if (!isa<Constant>(Ptr)) { | |||
| 5587 | // Not a GEP, maybe its a splat and we can create a GEP to enable | |||
| 5588 | // SelectionDAGBuilder to use it as a uniform base. | |||
| 5589 | Value *V = getSplatValue(Ptr); | |||
| 5590 | if (!V) | |||
| 5591 | return false; | |||
| 5592 | ||||
| 5593 | auto NumElts = cast<VectorType>(Ptr->getType())->getElementCount(); | |||
| 5594 | ||||
| 5595 | IRBuilder<> Builder(MemoryInst); | |||
| 5596 | ||||
| 5597 | // Emit a vector GEP with a scalar pointer and all 0s vector index. | |||
| 5598 | Type *ScalarIndexTy = DL->getIndexType(V->getType()->getScalarType()); | |||
| 5599 | auto *IndexTy = VectorType::get(ScalarIndexTy, NumElts); | |||
| 5600 | Type *ScalarTy; | |||
| 5601 | if (cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() == | |||
| 5602 | Intrinsic::masked_gather) { | |||
| 5603 | ScalarTy = MemoryInst->getType()->getScalarType(); | |||
| 5604 | } else { | |||
| 5605 | assert(cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() ==((void)0) | |||
| 5606 | Intrinsic::masked_scatter)((void)0); | |||
| 5607 | ScalarTy = MemoryInst->getOperand(0)->getType()->getScalarType(); | |||
| 5608 | } | |||
| 5609 | NewAddr = Builder.CreateGEP(ScalarTy, V, Constant::getNullValue(IndexTy)); | |||
| 5610 | } else { | |||
| 5611 | // Constant, SelectionDAGBuilder knows to check if its a splat. | |||
| 5612 | return false; | |||
| 5613 | } | |||
| 5614 | ||||
| 5615 | MemoryInst->replaceUsesOfWith(Ptr, NewAddr); | |||
| 5616 | ||||
| 5617 | // If we have no uses, recursively delete the value and all dead instructions | |||
| 5618 | // using it. | |||
| 5619 | if (Ptr->use_empty()) | |||
| 5620 | RecursivelyDeleteTriviallyDeadInstructions( | |||
| 5621 | Ptr, TLInfo, nullptr, | |||
| 5622 | [&](Value *V) { removeAllAssertingVHReferences(V); }); | |||
| 5623 | ||||
| 5624 | return true; | |||
| 5625 | } | |||
| 5626 | ||||
| 5627 | /// If there are any memory operands, use OptimizeMemoryInst to sink their | |||
| 5628 | /// address computing into the block when possible / profitable. | |||
| 5629 | bool CodeGenPrepare::optimizeInlineAsmInst(CallInst *CS) { | |||
| 5630 | bool MadeChange = false; | |||
| 5631 | ||||
| 5632 | const TargetRegisterInfo *TRI = | |||
| 5633 | TM->getSubtargetImpl(*CS->getFunction())->getRegisterInfo(); | |||
| 5634 | TargetLowering::AsmOperandInfoVector TargetConstraints = | |||
| 5635 | TLI->ParseConstraints(*DL, TRI, *CS); | |||
| 5636 | unsigned ArgNo = 0; | |||
| 5637 | for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) { | |||
| 5638 | TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i]; | |||
| 5639 | ||||
| 5640 | // Compute the constraint code and ConstraintType to use. | |||
| 5641 | TLI->ComputeConstraintToUse(OpInfo, SDValue()); | |||
| 5642 | ||||
| 5643 | if (OpInfo.ConstraintType == TargetLowering::C_Memory && | |||
| 5644 | OpInfo.isIndirect) { | |||
| 5645 | Value *OpVal = CS->getArgOperand(ArgNo++); | |||
| 5646 | MadeChange |= optimizeMemoryInst(CS, OpVal, OpVal->getType(), ~0u); | |||
| 5647 | } else if (OpInfo.Type == InlineAsm::isInput) | |||
| 5648 | ArgNo++; | |||
| 5649 | } | |||
| 5650 | ||||
| 5651 | return MadeChange; | |||
| 5652 | } | |||
| 5653 | ||||
| 5654 | /// Check if all the uses of \p Val are equivalent (or free) zero or | |||
| 5655 | /// sign extensions. | |||
| 5656 | static bool hasSameExtUse(Value *Val, const TargetLowering &TLI) { | |||
| 5657 | assert(!Val->use_empty() && "Input must have at least one use")((void)0); | |||
| 5658 | const Instruction *FirstUser = cast<Instruction>(*Val->user_begin()); | |||
| 5659 | bool IsSExt = isa<SExtInst>(FirstUser); | |||
| 5660 | Type *ExtTy = FirstUser->getType(); | |||
| 5661 | for (const User *U : Val->users()) { | |||
| 5662 | const Instruction *UI = cast<Instruction>(U); | |||
| 5663 | if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI))) | |||
| 5664 | return false; | |||
| 5665 | Type *CurTy = UI->getType(); | |||
| 5666 | // Same input and output types: Same instruction after CSE. | |||
| 5667 | if (CurTy == ExtTy) | |||
| 5668 | continue; | |||
| 5669 | ||||
| 5670 | // If IsSExt is true, we are in this situation: | |||
| 5671 | // a = Val | |||
| 5672 | // b = sext ty1 a to ty2 | |||
| 5673 | // c = sext ty1 a to ty3 | |||
| 5674 | // Assuming ty2 is shorter than ty3, this could be turned into: | |||
| 5675 | // a = Val | |||
| 5676 | // b = sext ty1 a to ty2 | |||
| 5677 | // c = sext ty2 b to ty3 | |||
| 5678 | // However, the last sext is not free. | |||
| 5679 | if (IsSExt) | |||
| 5680 | return false; | |||
| 5681 | ||||
| 5682 | // This is a ZExt, maybe this is free to extend from one type to another. | |||
| 5683 | // In that case, we would not account for a different use. | |||
| 5684 | Type *NarrowTy; | |||
| 5685 | Type *LargeTy; | |||
| 5686 | if (ExtTy->getScalarType()->getIntegerBitWidth() > | |||
| 5687 | CurTy->getScalarType()->getIntegerBitWidth()) { | |||
| 5688 | NarrowTy = CurTy; | |||
| 5689 | LargeTy = ExtTy; | |||
| 5690 | } else { | |||
| 5691 | NarrowTy = ExtTy; | |||
| 5692 | LargeTy = CurTy; | |||
| 5693 | } | |||
| 5694 | ||||
| 5695 | if (!TLI.isZExtFree(NarrowTy, LargeTy)) | |||
| 5696 | return false; | |||
| 5697 | } | |||
| 5698 | // All uses are the same or can be derived from one another for free. | |||
| 5699 | return true; | |||
| 5700 | } | |||
| 5701 | ||||
| 5702 | /// Try to speculatively promote extensions in \p Exts and continue | |||
| 5703 | /// promoting through newly promoted operands recursively as far as doing so is | |||
| 5704 | /// profitable. Save extensions profitably moved up, in \p ProfitablyMovedExts. | |||
| 5705 | /// When some promotion happened, \p TPT contains the proper state to revert | |||
| 5706 | /// them. | |||
| 5707 | /// | |||
| 5708 | /// \return true if some promotion happened, false otherwise. | |||
| 5709 | bool CodeGenPrepare::tryToPromoteExts( | |||
| 5710 | TypePromotionTransaction &TPT, const SmallVectorImpl<Instruction *> &Exts, | |||
| 5711 | SmallVectorImpl<Instruction *> &ProfitablyMovedExts, | |||
| 5712 | unsigned CreatedInstsCost) { | |||
| 5713 | bool Promoted = false; | |||
| 5714 | ||||
| 5715 | // Iterate over all the extensions to try to promote them. | |||
| 5716 | for (auto *I : Exts) { | |||
| 5717 | // Early check if we directly have ext(load). | |||
| 5718 | if (isa<LoadInst>(I->getOperand(0))) { | |||
| 5719 | ProfitablyMovedExts.push_back(I); | |||
| 5720 | continue; | |||
| 5721 | } | |||
| 5722 | ||||
| 5723 | // Check whether or not we want to do any promotion. The reason we have | |||
| 5724 | // this check inside the for loop is to catch the case where an extension | |||
| 5725 | // is directly fed by a load because in such case the extension can be moved | |||
| 5726 | // up without any promotion on its operands. | |||
| 5727 | if (!TLI->enableExtLdPromotion() || DisableExtLdPromotion) | |||
| 5728 | return false; | |||
| 5729 | ||||
| 5730 | // Get the action to perform the promotion. | |||
| 5731 | TypePromotionHelper::Action TPH = | |||
| 5732 | TypePromotionHelper::getAction(I, InsertedInsts, *TLI, PromotedInsts); | |||
| 5733 | // Check if we can promote. | |||
| 5734 | if (!TPH) { | |||
| 5735 | // Save the current extension as we cannot move up through its operand. | |||
| 5736 | ProfitablyMovedExts.push_back(I); | |||
| 5737 | continue; | |||
| 5738 | } | |||
| 5739 | ||||
| 5740 | // Save the current state. | |||
| 5741 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 5742 | TPT.getRestorationPoint(); | |||
| 5743 | SmallVector<Instruction *, 4> NewExts; | |||
| 5744 | unsigned NewCreatedInstsCost = 0; | |||
| 5745 | unsigned ExtCost = !TLI->isExtFree(I); | |||
| 5746 | // Promote. | |||
| 5747 | Value *PromotedVal = TPH(I, TPT, PromotedInsts, NewCreatedInstsCost, | |||
| 5748 | &NewExts, nullptr, *TLI); | |||
| 5749 | assert(PromotedVal &&((void)0) | |||
| 5750 | "TypePromotionHelper should have filtered out those cases")((void)0); | |||
| 5751 | ||||
| 5752 | // We would be able to merge only one extension in a load. | |||
| 5753 | // Therefore, if we have more than 1 new extension we heuristically | |||
| 5754 | // cut this search path, because it means we degrade the code quality. | |||
| 5755 | // With exactly 2, the transformation is neutral, because we will merge | |||
| 5756 | // one extension but leave one. However, we optimistically keep going, | |||
| 5757 | // because the new extension may be removed too. | |||
| 5758 | long long TotalCreatedInstsCost = CreatedInstsCost + NewCreatedInstsCost; | |||
| 5759 | // FIXME: It would be possible to propagate a negative value instead of | |||
| 5760 | // conservatively ceiling it to 0. | |||
| 5761 | TotalCreatedInstsCost = | |||
| 5762 | std::max((long long)0, (TotalCreatedInstsCost - ExtCost)); | |||
| 5763 | if (!StressExtLdPromotion && | |||
| 5764 | (TotalCreatedInstsCost > 1 || | |||
| 5765 | !isPromotedInstructionLegal(*TLI, *DL, PromotedVal))) { | |||
| 5766 | // This promotion is not profitable, rollback to the previous state, and | |||
| 5767 | // save the current extension in ProfitablyMovedExts as the latest | |||
| 5768 | // speculative promotion turned out to be unprofitable. | |||
| 5769 | TPT.rollback(LastKnownGood); | |||
| 5770 | ProfitablyMovedExts.push_back(I); | |||
| 5771 | continue; | |||
| 5772 | } | |||
| 5773 | // Continue promoting NewExts as far as doing so is profitable. | |||
| 5774 | SmallVector<Instruction *, 2> NewlyMovedExts; | |||
| 5775 | (void)tryToPromoteExts(TPT, NewExts, NewlyMovedExts, TotalCreatedInstsCost); | |||
| 5776 | bool NewPromoted = false; | |||
| 5777 | for (auto *ExtInst : NewlyMovedExts) { | |||
| 5778 | Instruction *MovedExt = cast<Instruction>(ExtInst); | |||
| 5779 | Value *ExtOperand = MovedExt->getOperand(0); | |||
| 5780 | // If we have reached to a load, we need this extra profitability check | |||
| 5781 | // as it could potentially be merged into an ext(load). | |||
| 5782 | if (isa<LoadInst>(ExtOperand) && | |||
| 5783 | !(StressExtLdPromotion || NewCreatedInstsCost <= ExtCost || | |||
| 5784 | (ExtOperand->hasOneUse() || hasSameExtUse(ExtOperand, *TLI)))) | |||
| 5785 | continue; | |||
| 5786 | ||||
| 5787 | ProfitablyMovedExts.push_back(MovedExt); | |||
| 5788 | NewPromoted = true; | |||
| 5789 | } | |||
| 5790 | ||||
| 5791 | // If none of speculative promotions for NewExts is profitable, rollback | |||
| 5792 | // and save the current extension (I) as the last profitable extension. | |||
| 5793 | if (!NewPromoted) { | |||
| 5794 | TPT.rollback(LastKnownGood); | |||
| 5795 | ProfitablyMovedExts.push_back(I); | |||
| 5796 | continue; | |||
| 5797 | } | |||
| 5798 | // The promotion is profitable. | |||
| 5799 | Promoted = true; | |||
| 5800 | } | |||
| 5801 | return Promoted; | |||
| 5802 | } | |||
| 5803 | ||||
| 5804 | /// Merging redundant sexts when one is dominating the other. | |||
| 5805 | bool CodeGenPrepare::mergeSExts(Function &F) { | |||
| 5806 | bool Changed = false; | |||
| 5807 | for (auto &Entry : ValToSExtendedUses) { | |||
| 5808 | SExts &Insts = Entry.second; | |||
| 5809 | SExts CurPts; | |||
| 5810 | for (Instruction *Inst : Insts) { | |||
| 5811 | if (RemovedInsts.count(Inst) || !isa<SExtInst>(Inst) || | |||
| 5812 | Inst->getOperand(0) != Entry.first) | |||
| 5813 | continue; | |||
| 5814 | bool inserted = false; | |||
| 5815 | for (auto &Pt : CurPts) { | |||
| 5816 | if (getDT(F).dominates(Inst, Pt)) { | |||
| 5817 | Pt->replaceAllUsesWith(Inst); | |||
| 5818 | RemovedInsts.insert(Pt); | |||
| 5819 | Pt->removeFromParent(); | |||
| 5820 | Pt = Inst; | |||
| 5821 | inserted = true; | |||
| 5822 | Changed = true; | |||
| 5823 | break; | |||
| 5824 | } | |||
| 5825 | if (!getDT(F).dominates(Pt, Inst)) | |||
| 5826 | // Give up if we need to merge in a common dominator as the | |||
| 5827 | // experiments show it is not profitable. | |||
| 5828 | continue; | |||
| 5829 | Inst->replaceAllUsesWith(Pt); | |||
| 5830 | RemovedInsts.insert(Inst); | |||
| 5831 | Inst->removeFromParent(); | |||
| 5832 | inserted = true; | |||
| 5833 | Changed = true; | |||
| 5834 | break; | |||
| 5835 | } | |||
| 5836 | if (!inserted) | |||
| 5837 | CurPts.push_back(Inst); | |||
| 5838 | } | |||
| 5839 | } | |||
| 5840 | return Changed; | |||
| 5841 | } | |||
| 5842 | ||||
| 5843 | // Splitting large data structures so that the GEPs accessing them can have | |||
| 5844 | // smaller offsets so that they can be sunk to the same blocks as their users. | |||
| 5845 | // For example, a large struct starting from %base is split into two parts | |||
| 5846 | // where the second part starts from %new_base. | |||
| 5847 | // | |||
| 5848 | // Before: | |||
| 5849 | // BB0: | |||
| 5850 | // %base = | |||
| 5851 | // | |||
| 5852 | // BB1: | |||
| 5853 | // %gep0 = gep %base, off0 | |||
| 5854 | // %gep1 = gep %base, off1 | |||
| 5855 | // %gep2 = gep %base, off2 | |||
| 5856 | // | |||
| 5857 | // BB2: | |||
| 5858 | // %load1 = load %gep0 | |||
| 5859 | // %load2 = load %gep1 | |||
| 5860 | // %load3 = load %gep2 | |||
| 5861 | // | |||
| 5862 | // After: | |||
| 5863 | // BB0: | |||
| 5864 | // %base = | |||
| 5865 | // %new_base = gep %base, off0 | |||
| 5866 | // | |||
| 5867 | // BB1: | |||
| 5868 | // %new_gep0 = %new_base | |||
| 5869 | // %new_gep1 = gep %new_base, off1 - off0 | |||
| 5870 | // %new_gep2 = gep %new_base, off2 - off0 | |||
| 5871 | // | |||
| 5872 | // BB2: | |||
| 5873 | // %load1 = load i32, i32* %new_gep0 | |||
| 5874 | // %load2 = load i32, i32* %new_gep1 | |||
| 5875 | // %load3 = load i32, i32* %new_gep2 | |||
| 5876 | // | |||
| 5877 | // %new_gep1 and %new_gep2 can be sunk to BB2 now after the splitting because | |||
| 5878 | // their offsets are smaller enough to fit into the addressing mode. | |||
| 5879 | bool CodeGenPrepare::splitLargeGEPOffsets() { | |||
| 5880 | bool Changed = false; | |||
| 5881 | for (auto &Entry : LargeOffsetGEPMap) { | |||
| 5882 | Value *OldBase = Entry.first; | |||
| 5883 | SmallVectorImpl<std::pair<AssertingVH<GetElementPtrInst>, int64_t>> | |||
| 5884 | &LargeOffsetGEPs = Entry.second; | |||
| 5885 | auto compareGEPOffset = | |||
| 5886 | [&](const std::pair<GetElementPtrInst *, int64_t> &LHS, | |||
| 5887 | const std::pair<GetElementPtrInst *, int64_t> &RHS) { | |||
| 5888 | if (LHS.first == RHS.first) | |||
| 5889 | return false; | |||
| 5890 | if (LHS.second != RHS.second) | |||
| 5891 | return LHS.second < RHS.second; | |||
| 5892 | return LargeOffsetGEPID[LHS.first] < LargeOffsetGEPID[RHS.first]; | |||
| 5893 | }; | |||
| 5894 | // Sorting all the GEPs of the same data structures based on the offsets. | |||
| 5895 | llvm::sort(LargeOffsetGEPs, compareGEPOffset); | |||
| 5896 | LargeOffsetGEPs.erase( | |||
| 5897 | std::unique(LargeOffsetGEPs.begin(), LargeOffsetGEPs.end()), | |||
| 5898 | LargeOffsetGEPs.end()); | |||
| 5899 | // Skip if all the GEPs have the same offsets. | |||
| 5900 | if (LargeOffsetGEPs.front().second == LargeOffsetGEPs.back().second) | |||
| 5901 | continue; | |||
| 5902 | GetElementPtrInst *BaseGEP = LargeOffsetGEPs.begin()->first; | |||
| 5903 | int64_t BaseOffset = LargeOffsetGEPs.begin()->second; | |||
| 5904 | Value *NewBaseGEP = nullptr; | |||
| 5905 | ||||
| 5906 | auto *LargeOffsetGEP = LargeOffsetGEPs.begin(); | |||
| 5907 | while (LargeOffsetGEP != LargeOffsetGEPs.end()) { | |||
| 5908 | GetElementPtrInst *GEP = LargeOffsetGEP->first; | |||
| 5909 | int64_t Offset = LargeOffsetGEP->second; | |||
| 5910 | if (Offset != BaseOffset) { | |||
| 5911 | TargetLowering::AddrMode AddrMode; | |||
| 5912 | AddrMode.BaseOffs = Offset - BaseOffset; | |||
| 5913 | // The result type of the GEP might not be the type of the memory | |||
| 5914 | // access. | |||
| 5915 | if (!TLI->isLegalAddressingMode(*DL, AddrMode, | |||
| 5916 | GEP->getResultElementType(), | |||
| 5917 | GEP->getAddressSpace())) { | |||
| 5918 | // We need to create a new base if the offset to the current base is | |||
| 5919 | // too large to fit into the addressing mode. So, a very large struct | |||
| 5920 | // may be split into several parts. | |||
| 5921 | BaseGEP = GEP; | |||
| 5922 | BaseOffset = Offset; | |||
| 5923 | NewBaseGEP = nullptr; | |||
| 5924 | } | |||
| 5925 | } | |||
| 5926 | ||||
| 5927 | // Generate a new GEP to replace the current one. | |||
| 5928 | LLVMContext &Ctx = GEP->getContext(); | |||
| 5929 | Type *IntPtrTy = DL->getIntPtrType(GEP->getType()); | |||
| 5930 | Type *I8PtrTy = | |||
| 5931 | Type::getInt8PtrTy(Ctx, GEP->getType()->getPointerAddressSpace()); | |||
| 5932 | Type *I8Ty = Type::getInt8Ty(Ctx); | |||
| 5933 | ||||
| 5934 | if (!NewBaseGEP) { | |||
| 5935 | // Create a new base if we don't have one yet. Find the insertion | |||
| 5936 | // pointer for the new base first. | |||
| 5937 | BasicBlock::iterator NewBaseInsertPt; | |||
| 5938 | BasicBlock *NewBaseInsertBB; | |||
| 5939 | if (auto *BaseI = dyn_cast<Instruction>(OldBase)) { | |||
| 5940 | // If the base of the struct is an instruction, the new base will be | |||
| 5941 | // inserted close to it. | |||
| 5942 | NewBaseInsertBB = BaseI->getParent(); | |||
| 5943 | if (isa<PHINode>(BaseI)) | |||
| 5944 | NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt(); | |||
| 5945 | else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(BaseI)) { | |||
| 5946 | NewBaseInsertBB = | |||
| 5947 | SplitEdge(NewBaseInsertBB, Invoke->getNormalDest()); | |||
| 5948 | NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt(); | |||
| 5949 | } else | |||
| 5950 | NewBaseInsertPt = std::next(BaseI->getIterator()); | |||
| 5951 | } else { | |||
| 5952 | // If the current base is an argument or global value, the new base | |||
| 5953 | // will be inserted to the entry block. | |||
| 5954 | NewBaseInsertBB = &BaseGEP->getFunction()->getEntryBlock(); | |||
| 5955 | NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt(); | |||
| 5956 | } | |||
| 5957 | IRBuilder<> NewBaseBuilder(NewBaseInsertBB, NewBaseInsertPt); | |||
| 5958 | // Create a new base. | |||
| 5959 | Value *BaseIndex = ConstantInt::get(IntPtrTy, BaseOffset); | |||
| 5960 | NewBaseGEP = OldBase; | |||
| 5961 | if (NewBaseGEP->getType() != I8PtrTy) | |||
| 5962 | NewBaseGEP = NewBaseBuilder.CreatePointerCast(NewBaseGEP, I8PtrTy); | |||
| 5963 | NewBaseGEP = | |||
| 5964 | NewBaseBuilder.CreateGEP(I8Ty, NewBaseGEP, BaseIndex, "splitgep"); | |||
| 5965 | NewGEPBases.insert(NewBaseGEP); | |||
| 5966 | } | |||
| 5967 | ||||
| 5968 | IRBuilder<> Builder(GEP); | |||
| 5969 | Value *NewGEP = NewBaseGEP; | |||
| 5970 | if (Offset == BaseOffset) { | |||
| 5971 | if (GEP->getType() != I8PtrTy) | |||
| 5972 | NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType()); | |||
| 5973 | } else { | |||
| 5974 | // Calculate the new offset for the new GEP. | |||
| 5975 | Value *Index = ConstantInt::get(IntPtrTy, Offset - BaseOffset); | |||
| 5976 | NewGEP = Builder.CreateGEP(I8Ty, NewBaseGEP, Index); | |||
| 5977 | ||||
| 5978 | if (GEP->getType() != I8PtrTy) | |||
| 5979 | NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType()); | |||
| 5980 | } | |||
| 5981 | GEP->replaceAllUsesWith(NewGEP); | |||
| 5982 | LargeOffsetGEPID.erase(GEP); | |||
| 5983 | LargeOffsetGEP = LargeOffsetGEPs.erase(LargeOffsetGEP); | |||
| 5984 | GEP->eraseFromParent(); | |||
| 5985 | Changed = true; | |||
| 5986 | } | |||
| 5987 | } | |||
| 5988 | return Changed; | |||
| 5989 | } | |||
| 5990 | ||||
| 5991 | bool CodeGenPrepare::optimizePhiType( | |||
| 5992 | PHINode *I, SmallPtrSetImpl<PHINode *> &Visited, | |||
| 5993 | SmallPtrSetImpl<Instruction *> &DeletedInstrs) { | |||
| 5994 | // We are looking for a collection on interconnected phi nodes that together | |||
| 5995 | // only use loads/bitcasts and are used by stores/bitcasts, and the bitcasts | |||
| 5996 | // are of the same type. Convert the whole set of nodes to the type of the | |||
| 5997 | // bitcast. | |||
| 5998 | Type *PhiTy = I->getType(); | |||
| 5999 | Type *ConvertTy = nullptr; | |||
| 6000 | if (Visited.count(I) || | |||
| 6001 | (!I->getType()->isIntegerTy() && !I->getType()->isFloatingPointTy())) | |||
| 6002 | return false; | |||
| 6003 | ||||
| 6004 | SmallVector<Instruction *, 4> Worklist; | |||
| 6005 | Worklist.push_back(cast<Instruction>(I)); | |||
| 6006 | SmallPtrSet<PHINode *, 4> PhiNodes; | |||
| 6007 | PhiNodes.insert(I); | |||
| 6008 | Visited.insert(I); | |||
| 6009 | SmallPtrSet<Instruction *, 4> Defs; | |||
| 6010 | SmallPtrSet<Instruction *, 4> Uses; | |||
| 6011 | // This works by adding extra bitcasts between load/stores and removing | |||
| 6012 | // existing bicasts. If we have a phi(bitcast(load)) or a store(bitcast(phi)) | |||
| 6013 | // we can get in the situation where we remove a bitcast in one iteration | |||
| 6014 | // just to add it again in the next. We need to ensure that at least one | |||
| 6015 | // bitcast we remove are anchored to something that will not change back. | |||
| 6016 | bool AnyAnchored = false; | |||
| 6017 | ||||
| 6018 | while (!Worklist.empty()) { | |||
| 6019 | Instruction *II = Worklist.pop_back_val(); | |||
| 6020 | ||||
| 6021 | if (auto *Phi = dyn_cast<PHINode>(II)) { | |||
| 6022 | // Handle Defs, which might also be PHI's | |||
| 6023 | for (Value *V : Phi->incoming_values()) { | |||
| 6024 | if (auto *OpPhi = dyn_cast<PHINode>(V)) { | |||
| 6025 | if (!PhiNodes.count(OpPhi)) { | |||
| 6026 | if (Visited.count(OpPhi)) | |||
| 6027 | return false; | |||
| 6028 | PhiNodes.insert(OpPhi); | |||
| 6029 | Visited.insert(OpPhi); | |||
| 6030 | Worklist.push_back(OpPhi); | |||
| 6031 | } | |||
| 6032 | } else if (auto *OpLoad = dyn_cast<LoadInst>(V)) { | |||
| 6033 | if (!OpLoad->isSimple()) | |||
| 6034 | return false; | |||
| 6035 | if (!Defs.count(OpLoad)) { | |||
| 6036 | Defs.insert(OpLoad); | |||
| 6037 | Worklist.push_back(OpLoad); | |||
| 6038 | } | |||
| 6039 | } else if (auto *OpEx = dyn_cast<ExtractElementInst>(V)) { | |||
| 6040 | if (!Defs.count(OpEx)) { | |||
| 6041 | Defs.insert(OpEx); | |||
| 6042 | Worklist.push_back(OpEx); | |||
| 6043 | } | |||
| 6044 | } else if (auto *OpBC = dyn_cast<BitCastInst>(V)) { | |||
| 6045 | if (!ConvertTy) | |||
| 6046 | ConvertTy = OpBC->getOperand(0)->getType(); | |||
| 6047 | if (OpBC->getOperand(0)->getType() != ConvertTy) | |||
| 6048 | return false; | |||
| 6049 | if (!Defs.count(OpBC)) { | |||
| 6050 | Defs.insert(OpBC); | |||
| 6051 | Worklist.push_back(OpBC); | |||
| 6052 | AnyAnchored |= !isa<LoadInst>(OpBC->getOperand(0)) && | |||
| 6053 | !isa<ExtractElementInst>(OpBC->getOperand(0)); | |||
| 6054 | } | |||
| 6055 | } else if (!isa<UndefValue>(V)) { | |||
| 6056 | return false; | |||
| 6057 | } | |||
| 6058 | } | |||
| 6059 | } | |||
| 6060 | ||||
| 6061 | // Handle uses which might also be phi's | |||
| 6062 | for (User *V : II->users()) { | |||
| 6063 | if (auto *OpPhi = dyn_cast<PHINode>(V)) { | |||
| 6064 | if (!PhiNodes.count(OpPhi)) { | |||
| 6065 | if (Visited.count(OpPhi)) | |||
| 6066 | return false; | |||
| 6067 | PhiNodes.insert(OpPhi); | |||
| 6068 | Visited.insert(OpPhi); | |||
| 6069 | Worklist.push_back(OpPhi); | |||
| 6070 | } | |||
| 6071 | } else if (auto *OpStore = dyn_cast<StoreInst>(V)) { | |||
| 6072 | if (!OpStore->isSimple() || OpStore->getOperand(0) != II) | |||
| 6073 | return false; | |||
| 6074 | Uses.insert(OpStore); | |||
| 6075 | } else if (auto *OpBC = dyn_cast<BitCastInst>(V)) { | |||
| 6076 | if (!ConvertTy) | |||
| 6077 | ConvertTy = OpBC->getType(); | |||
| 6078 | if (OpBC->getType() != ConvertTy) | |||
| 6079 | return false; | |||
| 6080 | Uses.insert(OpBC); | |||
| 6081 | AnyAnchored |= | |||
| 6082 | any_of(OpBC->users(), [](User *U) { return !isa<StoreInst>(U); }); | |||
| 6083 | } else { | |||
| 6084 | return false; | |||
| 6085 | } | |||
| 6086 | } | |||
| 6087 | } | |||
| 6088 | ||||
| 6089 | if (!ConvertTy || !AnyAnchored || !TLI->shouldConvertPhiType(PhiTy, ConvertTy)) | |||
| 6090 | return false; | |||
| 6091 | ||||
| 6092 | LLVM_DEBUG(dbgs() << "Converting " << *I << "\n and connected nodes to "do { } while (false) | |||
| 6093 | << *ConvertTy << "\n")do { } while (false); | |||
| 6094 | ||||
| 6095 | // Create all the new phi nodes of the new type, and bitcast any loads to the | |||
| 6096 | // correct type. | |||
| 6097 | ValueToValueMap ValMap; | |||
| 6098 | ValMap[UndefValue::get(PhiTy)] = UndefValue::get(ConvertTy); | |||
| 6099 | for (Instruction *D : Defs) { | |||
| 6100 | if (isa<BitCastInst>(D)) { | |||
| 6101 | ValMap[D] = D->getOperand(0); | |||
| 6102 | DeletedInstrs.insert(D); | |||
| 6103 | } else { | |||
| 6104 | ValMap[D] = | |||
| 6105 | new BitCastInst(D, ConvertTy, D->getName() + ".bc", D->getNextNode()); | |||
| 6106 | } | |||
| 6107 | } | |||
| 6108 | for (PHINode *Phi : PhiNodes) | |||
| 6109 | ValMap[Phi] = PHINode::Create(ConvertTy, Phi->getNumIncomingValues(), | |||
| 6110 | Phi->getName() + ".tc", Phi); | |||
| 6111 | // Pipe together all the PhiNodes. | |||
| 6112 | for (PHINode *Phi : PhiNodes) { | |||
| 6113 | PHINode *NewPhi = cast<PHINode>(ValMap[Phi]); | |||
| 6114 | for (int i = 0, e = Phi->getNumIncomingValues(); i < e; i++) | |||
| 6115 | NewPhi->addIncoming(ValMap[Phi->getIncomingValue(i)], | |||
| 6116 | Phi->getIncomingBlock(i)); | |||
| 6117 | Visited.insert(NewPhi); | |||
| 6118 | } | |||
| 6119 | // And finally pipe up the stores and bitcasts | |||
| 6120 | for (Instruction *U : Uses) { | |||
| 6121 | if (isa<BitCastInst>(U)) { | |||
| 6122 | DeletedInstrs.insert(U); | |||
| 6123 | U->replaceAllUsesWith(ValMap[U->getOperand(0)]); | |||
| 6124 | } else { | |||
| 6125 | U->setOperand(0, | |||
| 6126 | new BitCastInst(ValMap[U->getOperand(0)], PhiTy, "bc", U)); | |||
| 6127 | } | |||
| 6128 | } | |||
| 6129 | ||||
| 6130 | // Save the removed phis to be deleted later. | |||
| 6131 | for (PHINode *Phi : PhiNodes) | |||
| 6132 | DeletedInstrs.insert(Phi); | |||
| 6133 | return true; | |||
| 6134 | } | |||
| 6135 | ||||
| 6136 | bool CodeGenPrepare::optimizePhiTypes(Function &F) { | |||
| 6137 | if (!OptimizePhiTypes) | |||
| 6138 | return false; | |||
| 6139 | ||||
| 6140 | bool Changed = false; | |||
| 6141 | SmallPtrSet<PHINode *, 4> Visited; | |||
| 6142 | SmallPtrSet<Instruction *, 4> DeletedInstrs; | |||
| 6143 | ||||
| 6144 | // Attempt to optimize all the phis in the functions to the correct type. | |||
| 6145 | for (auto &BB : F) | |||
| 6146 | for (auto &Phi : BB.phis()) | |||
| 6147 | Changed |= optimizePhiType(&Phi, Visited, DeletedInstrs); | |||
| 6148 | ||||
| 6149 | // Remove any old phi's that have been converted. | |||
| 6150 | for (auto *I : DeletedInstrs) { | |||
| 6151 | I->replaceAllUsesWith(UndefValue::get(I->getType())); | |||
| 6152 | I->eraseFromParent(); | |||
| 6153 | } | |||
| 6154 | ||||
| 6155 | return Changed; | |||
| 6156 | } | |||
| 6157 | ||||
| 6158 | /// Return true, if an ext(load) can be formed from an extension in | |||
| 6159 | /// \p MovedExts. | |||
| 6160 | bool CodeGenPrepare::canFormExtLd( | |||
| 6161 | const SmallVectorImpl<Instruction *> &MovedExts, LoadInst *&LI, | |||
| 6162 | Instruction *&Inst, bool HasPromoted) { | |||
| 6163 | for (auto *MovedExtInst : MovedExts) { | |||
| 6164 | if (isa<LoadInst>(MovedExtInst->getOperand(0))) { | |||
| 6165 | LI = cast<LoadInst>(MovedExtInst->getOperand(0)); | |||
| 6166 | Inst = MovedExtInst; | |||
| 6167 | break; | |||
| 6168 | } | |||
| 6169 | } | |||
| 6170 | if (!LI) | |||
| 6171 | return false; | |||
| 6172 | ||||
| 6173 | // If they're already in the same block, there's nothing to do. | |||
| 6174 | // Make the cheap checks first if we did not promote. | |||
| 6175 | // If we promoted, we need to check if it is indeed profitable. | |||
| 6176 | if (!HasPromoted && LI->getParent() == Inst->getParent()) | |||
| 6177 | return false; | |||
| 6178 | ||||
| 6179 | return TLI->isExtLoad(LI, Inst, *DL); | |||
| 6180 | } | |||
| 6181 | ||||
| 6182 | /// Move a zext or sext fed by a load into the same basic block as the load, | |||
| 6183 | /// unless conditions are unfavorable. This allows SelectionDAG to fold the | |||
| 6184 | /// extend into the load. | |||
| 6185 | /// | |||
| 6186 | /// E.g., | |||
| 6187 | /// \code | |||
| 6188 | /// %ld = load i32* %addr | |||
| 6189 | /// %add = add nuw i32 %ld, 4 | |||
| 6190 | /// %zext = zext i32 %add to i64 | |||
| 6191 | // \endcode | |||
| 6192 | /// => | |||
| 6193 | /// \code | |||
| 6194 | /// %ld = load i32* %addr | |||
| 6195 | /// %zext = zext i32 %ld to i64 | |||
| 6196 | /// %add = add nuw i64 %zext, 4 | |||
| 6197 | /// \encode | |||
| 6198 | /// Note that the promotion in %add to i64 is done in tryToPromoteExts(), which | |||
| 6199 | /// allow us to match zext(load i32*) to i64. | |||
| 6200 | /// | |||
| 6201 | /// Also, try to promote the computations used to obtain a sign extended | |||
| 6202 | /// value used into memory accesses. | |||
| 6203 | /// E.g., | |||
| 6204 | /// \code | |||
| 6205 | /// a = add nsw i32 b, 3 | |||
| 6206 | /// d = sext i32 a to i64 | |||
| 6207 | /// e = getelementptr ..., i64 d | |||
| 6208 | /// \endcode | |||
| 6209 | /// => | |||
| 6210 | /// \code | |||
| 6211 | /// f = sext i32 b to i64 | |||
| 6212 | /// a = add nsw i64 f, 3 | |||
| 6213 | /// e = getelementptr ..., i64 a | |||
| 6214 | /// \endcode | |||
| 6215 | /// | |||
| 6216 | /// \p Inst[in/out] the extension may be modified during the process if some | |||
| 6217 | /// promotions apply. | |||
| 6218 | bool CodeGenPrepare::optimizeExt(Instruction *&Inst) { | |||
| 6219 | bool AllowPromotionWithoutCommonHeader = false; | |||
| 6220 | /// See if it is an interesting sext operations for the address type | |||
| 6221 | /// promotion before trying to promote it, e.g., the ones with the right | |||
| 6222 | /// type and used in memory accesses. | |||
| 6223 | bool ATPConsiderable = TTI->shouldConsiderAddressTypePromotion( | |||
| 6224 | *Inst, AllowPromotionWithoutCommonHeader); | |||
| 6225 | TypePromotionTransaction TPT(RemovedInsts); | |||
| 6226 | TypePromotionTransaction::ConstRestorationPt LastKnownGood = | |||
| 6227 | TPT.getRestorationPoint(); | |||
| 6228 | SmallVector<Instruction *, 1> Exts; | |||
| 6229 | SmallVector<Instruction *, 2> SpeculativelyMovedExts; | |||
| 6230 | Exts.push_back(Inst); | |||
| 6231 | ||||
| 6232 | bool HasPromoted = tryToPromoteExts(TPT, Exts, SpeculativelyMovedExts); | |||
| 6233 | ||||
| 6234 | // Look for a load being extended. | |||
| 6235 | LoadInst *LI = nullptr; | |||
| 6236 | Instruction *ExtFedByLoad; | |||
| 6237 | ||||
| 6238 | // Try to promote a chain of computation if it allows to form an extended | |||
| 6239 | // load. | |||
| 6240 | if (canFormExtLd(SpeculativelyMovedExts, LI, ExtFedByLoad, HasPromoted)) { | |||
| 6241 | assert(LI && ExtFedByLoad && "Expect a valid load and extension")((void)0); | |||
| 6242 | TPT.commit(); | |||
| 6243 | // Move the extend into the same block as the load. | |||
| 6244 | ExtFedByLoad->moveAfter(LI); | |||
| 6245 | ++NumExtsMoved; | |||
| 6246 | Inst = ExtFedByLoad; | |||
| 6247 | return true; | |||
| 6248 | } | |||
| 6249 | ||||
| 6250 | // Continue promoting SExts if known as considerable depending on targets. | |||
| 6251 | if (ATPConsiderable && | |||
| 6252 | performAddressTypePromotion(Inst, AllowPromotionWithoutCommonHeader, | |||
| 6253 | HasPromoted, TPT, SpeculativelyMovedExts)) | |||
| 6254 | return true; | |||
| 6255 | ||||
| 6256 | TPT.rollback(LastKnownGood); | |||
| 6257 | return false; | |||
| 6258 | } | |||
| 6259 | ||||
| 6260 | // Perform address type promotion if doing so is profitable. | |||
| 6261 | // If AllowPromotionWithoutCommonHeader == false, we should find other sext | |||
| 6262 | // instructions that sign extended the same initial value. However, if | |||
| 6263 | // AllowPromotionWithoutCommonHeader == true, we expect promoting the | |||
| 6264 | // extension is just profitable. | |||
| 6265 | bool CodeGenPrepare::performAddressTypePromotion( | |||
| 6266 | Instruction *&Inst, bool AllowPromotionWithoutCommonHeader, | |||
| 6267 | bool HasPromoted, TypePromotionTransaction &TPT, | |||
| 6268 | SmallVectorImpl<Instruction *> &SpeculativelyMovedExts) { | |||
| 6269 | bool Promoted = false; | |||
| 6270 | SmallPtrSet<Instruction *, 1> UnhandledExts; | |||
| 6271 | bool AllSeenFirst = true; | |||
| 6272 | for (auto *I : SpeculativelyMovedExts) { | |||
| 6273 | Value *HeadOfChain = I->getOperand(0); | |||
| 6274 | DenseMap<Value *, Instruction *>::iterator AlreadySeen = | |||
| 6275 | SeenChainsForSExt.find(HeadOfChain); | |||
| 6276 | // If there is an unhandled SExt which has the same header, try to promote | |||
| 6277 | // it as well. | |||
| 6278 | if (AlreadySeen != SeenChainsForSExt.end()) { | |||
| 6279 | if (AlreadySeen->second != nullptr) | |||
| 6280 | UnhandledExts.insert(AlreadySeen->second); | |||
| 6281 | AllSeenFirst = false; | |||
| 6282 | } | |||
| 6283 | } | |||
| 6284 | ||||
| 6285 | if (!AllSeenFirst || (AllowPromotionWithoutCommonHeader && | |||
| 6286 | SpeculativelyMovedExts.size() == 1)) { | |||
| 6287 | TPT.commit(); | |||
| 6288 | if (HasPromoted) | |||
| 6289 | Promoted = true; | |||
| 6290 | for (auto *I : SpeculativelyMovedExts) { | |||
| 6291 | Value *HeadOfChain = I->getOperand(0); | |||
| 6292 | SeenChainsForSExt[HeadOfChain] = nullptr; | |||
| 6293 | ValToSExtendedUses[HeadOfChain].push_back(I); | |||
| 6294 | } | |||
| 6295 | // Update Inst as promotion happen. | |||
| 6296 | Inst = SpeculativelyMovedExts.pop_back_val(); | |||
| 6297 | } else { | |||
| 6298 | // This is the first chain visited from the header, keep the current chain | |||
| 6299 | // as unhandled. Defer to promote this until we encounter another SExt | |||
| 6300 | // chain derived from the same header. | |||
| 6301 | for (auto *I : SpeculativelyMovedExts) { | |||
| 6302 | Value *HeadOfChain = I->getOperand(0); | |||
| 6303 | SeenChainsForSExt[HeadOfChain] = Inst; | |||
| 6304 | } | |||
| 6305 | return false; | |||
| 6306 | } | |||
| 6307 | ||||
| 6308 | if (!AllSeenFirst && !UnhandledExts.empty()) | |||
| 6309 | for (auto *VisitedSExt : UnhandledExts) { | |||
| 6310 | if (RemovedInsts.count(VisitedSExt)) | |||
| 6311 | continue; | |||
| 6312 | TypePromotionTransaction TPT(RemovedInsts); | |||
| 6313 | SmallVector<Instruction *, 1> Exts; | |||
| 6314 | SmallVector<Instruction *, 2> Chains; | |||
| 6315 | Exts.push_back(VisitedSExt); | |||
| 6316 | bool HasPromoted = tryToPromoteExts(TPT, Exts, Chains); | |||
| 6317 | TPT.commit(); | |||
| 6318 | if (HasPromoted) | |||
| 6319 | Promoted = true; | |||
| 6320 | for (auto *I : Chains) { | |||
| 6321 | Value *HeadOfChain = I->getOperand(0); | |||
| 6322 | // Mark this as handled. | |||
| 6323 | SeenChainsForSExt[HeadOfChain] = nullptr; | |||
| 6324 | ValToSExtendedUses[HeadOfChain].push_back(I); | |||
| 6325 | } | |||
| 6326 | } | |||
| 6327 | return Promoted; | |||
| 6328 | } | |||
| 6329 | ||||
| 6330 | bool CodeGenPrepare::optimizeExtUses(Instruction *I) { | |||
| 6331 | BasicBlock *DefBB = I->getParent(); | |||
| 6332 | ||||
| 6333 | // If the result of a {s|z}ext and its source are both live out, rewrite all | |||
| 6334 | // other uses of the source with result of extension. | |||
| 6335 | Value *Src = I->getOperand(0); | |||
| 6336 | if (Src->hasOneUse()) | |||
| 6337 | return false; | |||
| 6338 | ||||
| 6339 | // Only do this xform if truncating is free. | |||
| 6340 | if (!TLI->isTruncateFree(I->getType(), Src->getType())) | |||
| 6341 | return false; | |||
| 6342 | ||||
| 6343 | // Only safe to perform the optimization if the source is also defined in | |||
| 6344 | // this block. | |||
| 6345 | if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent()) | |||
| 6346 | return false; | |||
| 6347 | ||||
| 6348 | bool DefIsLiveOut = false; | |||
| 6349 | for (User *U : I->users()) { | |||
| 6350 | Instruction *UI = cast<Instruction>(U); | |||
| 6351 | ||||
| 6352 | // Figure out which BB this ext is used in. | |||
| 6353 | BasicBlock *UserBB = UI->getParent(); | |||
| 6354 | if (UserBB == DefBB) continue; | |||
| 6355 | DefIsLiveOut = true; | |||
| 6356 | break; | |||
| 6357 | } | |||
| 6358 | if (!DefIsLiveOut) | |||
| 6359 | return false; | |||
| 6360 | ||||
| 6361 | // Make sure none of the uses are PHI nodes. | |||
| 6362 | for (User *U : Src->users()) { | |||
| 6363 | Instruction *UI = cast<Instruction>(U); | |||
| 6364 | BasicBlock *UserBB = UI->getParent(); | |||
| 6365 | if (UserBB == DefBB) continue; | |||
| 6366 | // Be conservative. We don't want this xform to end up introducing | |||
| 6367 | // reloads just before load / store instructions. | |||
| 6368 | if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI)) | |||
| 6369 | return false; | |||
| 6370 | } | |||
| 6371 | ||||
| 6372 | // InsertedTruncs - Only insert one trunc in each block once. | |||
| 6373 | DenseMap<BasicBlock*, Instruction*> InsertedTruncs; | |||
| 6374 | ||||
| 6375 | bool MadeChange = false; | |||
| 6376 | for (Use &U : Src->uses()) { | |||
| 6377 | Instruction *User = cast<Instruction>(U.getUser()); | |||
| 6378 | ||||
| 6379 | // Figure out which BB this ext is used in. | |||
| 6380 | BasicBlock *UserBB = User->getParent(); | |||
| 6381 | if (UserBB == DefBB) continue; | |||
| 6382 | ||||
| 6383 | // Both src and def are live in this block. Rewrite the use. | |||
| 6384 | Instruction *&InsertedTrunc = InsertedTruncs[UserBB]; | |||
| 6385 | ||||
| 6386 | if (!InsertedTrunc) { | |||
| 6387 | BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt(); | |||
| 6388 | assert(InsertPt != UserBB->end())((void)0); | |||
| 6389 | InsertedTrunc = new TruncInst(I, Src->getType(), "", &*InsertPt); | |||
| 6390 | InsertedInsts.insert(InsertedTrunc); | |||
| 6391 | } | |||
| 6392 | ||||
| 6393 | // Replace a use of the {s|z}ext source with a use of the result. | |||
| 6394 | U = InsertedTrunc; | |||
| 6395 | ++NumExtUses; | |||
| 6396 | MadeChange = true; | |||
| 6397 | } | |||
| 6398 | ||||
| 6399 | return MadeChange; | |||
| 6400 | } | |||
| 6401 | ||||
| 6402 | // Find loads whose uses only use some of the loaded value's bits. Add an "and" | |||
| 6403 | // just after the load if the target can fold this into one extload instruction, | |||
| 6404 | // with the hope of eliminating some of the other later "and" instructions using | |||
| 6405 | // the loaded value. "and"s that are made trivially redundant by the insertion | |||
| 6406 | // of the new "and" are removed by this function, while others (e.g. those whose | |||
| 6407 | // path from the load goes through a phi) are left for isel to potentially | |||
| 6408 | // remove. | |||
| 6409 | // | |||
| 6410 | // For example: | |||
| 6411 | // | |||
| 6412 | // b0: | |||
| 6413 | // x = load i32 | |||
| 6414 | // ... | |||
| 6415 | // b1: | |||
| 6416 | // y = and x, 0xff | |||
| 6417 | // z = use y | |||
| 6418 | // | |||
| 6419 | // becomes: | |||
| 6420 | // | |||
| 6421 | // b0: | |||
| 6422 | // x = load i32 | |||
| 6423 | // x' = and x, 0xff | |||
| 6424 | // ... | |||
| 6425 | // b1: | |||
| 6426 | // z = use x' | |||
| 6427 | // | |||
| 6428 | // whereas: | |||
| 6429 | // | |||
| 6430 | // b0: | |||
| 6431 | // x1 = load i32 | |||
| 6432 | // ... | |||
| 6433 | // b1: | |||
| 6434 | // x2 = load i32 | |||
| 6435 | // ... | |||
| 6436 | // b2: | |||
| 6437 | // x = phi x1, x2 | |||
| 6438 | // y = and x, 0xff | |||
| 6439 | // | |||
| 6440 | // becomes (after a call to optimizeLoadExt for each load): | |||
| 6441 | // | |||
| 6442 | // b0: | |||
| 6443 | // x1 = load i32 | |||
| 6444 | // x1' = and x1, 0xff | |||
| 6445 | // ... | |||
| 6446 | // b1: | |||
| 6447 | // x2 = load i32 | |||
| 6448 | // x2' = and x2, 0xff | |||
| 6449 | // ... | |||
| 6450 | // b2: | |||
| 6451 | // x = phi x1', x2' | |||
| 6452 | // y = and x, 0xff | |||
| 6453 | bool CodeGenPrepare::optimizeLoadExt(LoadInst *Load) { | |||
| 6454 | if (!Load->isSimple() || !Load->getType()->isIntOrPtrTy()) | |||
| 6455 | return false; | |||
| 6456 | ||||
| 6457 | // Skip loads we've already transformed. | |||
| 6458 | if (Load->hasOneUse() && | |||
| 6459 | InsertedInsts.count(cast<Instruction>(*Load->user_begin()))) | |||
| 6460 | return false; | |||
| 6461 | ||||
| 6462 | // Look at all uses of Load, looking through phis, to determine how many bits | |||
| 6463 | // of the loaded value are needed. | |||
| 6464 | SmallVector<Instruction *, 8> WorkList; | |||
| 6465 | SmallPtrSet<Instruction *, 16> Visited; | |||
| 6466 | SmallVector<Instruction *, 8> AndsToMaybeRemove; | |||
| 6467 | for (auto *U : Load->users()) | |||
| 6468 | WorkList.push_back(cast<Instruction>(U)); | |||
| 6469 | ||||
| 6470 | EVT LoadResultVT = TLI->getValueType(*DL, Load->getType()); | |||
| 6471 | unsigned BitWidth = LoadResultVT.getSizeInBits(); | |||
| 6472 | // If the BitWidth is 0, do not try to optimize the type | |||
| 6473 | if (BitWidth == 0) | |||
| 6474 | return false; | |||
| 6475 | ||||
| 6476 | APInt DemandBits(BitWidth, 0); | |||
| 6477 | APInt WidestAndBits(BitWidth, 0); | |||
| 6478 | ||||
| 6479 | while (!WorkList.empty()) { | |||
| 6480 | Instruction *I = WorkList.back(); | |||
| 6481 | WorkList.pop_back(); | |||
| 6482 | ||||
| 6483 | // Break use-def graph loops. | |||
| 6484 | if (!Visited.insert(I).second) | |||
| 6485 | continue; | |||
| 6486 | ||||
| 6487 | // For a PHI node, push all of its users. | |||
| 6488 | if (auto *Phi = dyn_cast<PHINode>(I)) { | |||
| 6489 | for (auto *U : Phi->users()) | |||
| 6490 | WorkList.push_back(cast<Instruction>(U)); | |||
| 6491 | continue; | |||
| 6492 | } | |||
| 6493 | ||||
| 6494 | switch (I->getOpcode()) { | |||
| 6495 | case Instruction::And: { | |||
| 6496 | auto *AndC = dyn_cast<ConstantInt>(I->getOperand(1)); | |||
| 6497 | if (!AndC) | |||
| 6498 | return false; | |||
| 6499 | APInt AndBits = AndC->getValue(); | |||
| 6500 | DemandBits |= AndBits; | |||
| 6501 | // Keep track of the widest and mask we see. | |||
| 6502 | if (AndBits.ugt(WidestAndBits)) | |||
| 6503 | WidestAndBits = AndBits; | |||
| 6504 | if (AndBits == WidestAndBits && I->getOperand(0) == Load) | |||
| 6505 | AndsToMaybeRemove.push_back(I); | |||
| 6506 | break; | |||
| 6507 | } | |||
| 6508 | ||||
| 6509 | case Instruction::Shl: { | |||
| 6510 | auto *ShlC = dyn_cast<ConstantInt>(I->getOperand(1)); | |||
| 6511 | if (!ShlC) | |||
| 6512 | return false; | |||
| 6513 | uint64_t ShiftAmt = ShlC->getLimitedValue(BitWidth - 1); | |||
| 6514 | DemandBits.setLowBits(BitWidth - ShiftAmt); | |||
| 6515 | break; | |||
| 6516 | } | |||
| 6517 | ||||
| 6518 | case Instruction::Trunc: { | |||
| 6519 | EVT TruncVT = TLI->getValueType(*DL, I->getType()); | |||
| 6520 | unsigned TruncBitWidth = TruncVT.getSizeInBits(); | |||
| 6521 | DemandBits.setLowBits(TruncBitWidth); | |||
| 6522 | break; | |||
| 6523 | } | |||
| 6524 | ||||
| 6525 | default: | |||
| 6526 | return false; | |||
| 6527 | } | |||
| 6528 | } | |||
| 6529 | ||||
| 6530 | uint32_t ActiveBits = DemandBits.getActiveBits(); | |||
| 6531 | // Avoid hoisting (and (load x) 1) since it is unlikely to be folded by the | |||
| 6532 | // target even if isLoadExtLegal says an i1 EXTLOAD is valid. For example, | |||
| 6533 | // for the AArch64 target isLoadExtLegal(ZEXTLOAD, i32, i1) returns true, but | |||
| 6534 | // (and (load x) 1) is not matched as a single instruction, rather as a LDR | |||
| 6535 | // followed by an AND. | |||
| 6536 | // TODO: Look into removing this restriction by fixing backends to either | |||
| 6537 | // return false for isLoadExtLegal for i1 or have them select this pattern to | |||
| 6538 | // a single instruction. | |||
| 6539 | // | |||
| 6540 | // Also avoid hoisting if we didn't see any ands with the exact DemandBits | |||
| 6541 | // mask, since these are the only ands that will be removed by isel. | |||
| 6542 | if (ActiveBits <= 1 || !DemandBits.isMask(ActiveBits) || | |||
| 6543 | WidestAndBits != DemandBits) | |||
| 6544 | return false; | |||
| 6545 | ||||
| 6546 | LLVMContext &Ctx = Load->getType()->getContext(); | |||
| 6547 | Type *TruncTy = Type::getIntNTy(Ctx, ActiveBits); | |||
| 6548 | EVT TruncVT = TLI->getValueType(*DL, TruncTy); | |||
| 6549 | ||||
| 6550 | // Reject cases that won't be matched as extloads. | |||
| 6551 | if (!LoadResultVT.bitsGT(TruncVT) || !TruncVT.isRound() || | |||
| 6552 | !TLI->isLoadExtLegal(ISD::ZEXTLOAD, LoadResultVT, TruncVT)) | |||
| 6553 | return false; | |||
| 6554 | ||||
| 6555 | IRBuilder<> Builder(Load->getNextNode()); | |||
| 6556 | auto *NewAnd = cast<Instruction>( | |||
| 6557 | Builder.CreateAnd(Load, ConstantInt::get(Ctx, DemandBits))); | |||
| 6558 | // Mark this instruction as "inserted by CGP", so that other | |||
| 6559 | // optimizations don't touch it. | |||
| 6560 | InsertedInsts.insert(NewAnd); | |||
| 6561 | ||||
| 6562 | // Replace all uses of load with new and (except for the use of load in the | |||
| 6563 | // new and itself). | |||
| 6564 | Load->replaceAllUsesWith(NewAnd); | |||
| 6565 | NewAnd->setOperand(0, Load); | |||
| 6566 | ||||
| 6567 | // Remove any and instructions that are now redundant. | |||
| 6568 | for (auto *And : AndsToMaybeRemove) | |||
| 6569 | // Check that the and mask is the same as the one we decided to put on the | |||
| 6570 | // new and. | |||
| 6571 | if (cast<ConstantInt>(And->getOperand(1))->getValue() == DemandBits) { | |||
| 6572 | And->replaceAllUsesWith(NewAnd); | |||
| 6573 | if (&*CurInstIterator == And) | |||
| 6574 | CurInstIterator = std::next(And->getIterator()); | |||
| 6575 | And->eraseFromParent(); | |||
| 6576 | ++NumAndUses; | |||
| 6577 | } | |||
| 6578 | ||||
| 6579 | ++NumAndsAdded; | |||
| 6580 | return true; | |||
| 6581 | } | |||
| 6582 | ||||
| 6583 | /// Check if V (an operand of a select instruction) is an expensive instruction | |||
| 6584 | /// that is only used once. | |||
| 6585 | static bool sinkSelectOperand(const TargetTransformInfo *TTI, Value *V) { | |||
| 6586 | auto *I = dyn_cast<Instruction>(V); | |||
| 6587 | // If it's safe to speculatively execute, then it should not have side | |||
| 6588 | // effects; therefore, it's safe to sink and possibly *not* execute. | |||
| 6589 | return I && I->hasOneUse() && isSafeToSpeculativelyExecute(I) && | |||
| 6590 | TTI->getUserCost(I, TargetTransformInfo::TCK_SizeAndLatency) >= | |||
| 6591 | TargetTransformInfo::TCC_Expensive; | |||
| 6592 | } | |||
| 6593 | ||||
| 6594 | /// Returns true if a SelectInst should be turned into an explicit branch. | |||
| 6595 | static bool isFormingBranchFromSelectProfitable(const TargetTransformInfo *TTI, | |||
| 6596 | const TargetLowering *TLI, | |||
| 6597 | SelectInst *SI) { | |||
| 6598 | // If even a predictable select is cheap, then a branch can't be cheaper. | |||
| 6599 | if (!TLI->isPredictableSelectExpensive()) | |||
| 6600 | return false; | |||
| 6601 | ||||
| 6602 | // FIXME: This should use the same heuristics as IfConversion to determine | |||
| 6603 | // whether a select is better represented as a branch. | |||
| 6604 | ||||
| 6605 | // If metadata tells us that the select condition is obviously predictable, | |||
| 6606 | // then we want to replace the select with a branch. | |||
| 6607 | uint64_t TrueWeight, FalseWeight; | |||
| 6608 | if (SI->extractProfMetadata(TrueWeight, FalseWeight)) { | |||
| 6609 | uint64_t Max = std::max(TrueWeight, FalseWeight); | |||
| 6610 | uint64_t Sum = TrueWeight + FalseWeight; | |||
| 6611 | if (Sum != 0) { | |||
| 6612 | auto Probability = BranchProbability::getBranchProbability(Max, Sum); | |||
| 6613 | if (Probability > TTI->getPredictableBranchThreshold()) | |||
| 6614 | return true; | |||
| 6615 | } | |||
| 6616 | } | |||
| 6617 | ||||
| 6618 | CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition()); | |||
| 6619 | ||||
| 6620 | // If a branch is predictable, an out-of-order CPU can avoid blocking on its | |||
| 6621 | // comparison condition. If the compare has more than one use, there's | |||
| 6622 | // probably another cmov or setcc around, so it's not worth emitting a branch. | |||
| 6623 | if (!Cmp || !Cmp->hasOneUse()) | |||
| 6624 | return false; | |||
| 6625 | ||||
| 6626 | // If either operand of the select is expensive and only needed on one side | |||
| 6627 | // of the select, we should form a branch. | |||
| 6628 | if (sinkSelectOperand(TTI, SI->getTrueValue()) || | |||
| 6629 | sinkSelectOperand(TTI, SI->getFalseValue())) | |||
| 6630 | return true; | |||
| 6631 | ||||
| 6632 | return false; | |||
| 6633 | } | |||
| 6634 | ||||
| 6635 | /// If \p isTrue is true, return the true value of \p SI, otherwise return | |||
| 6636 | /// false value of \p SI. If the true/false value of \p SI is defined by any | |||
| 6637 | /// select instructions in \p Selects, look through the defining select | |||
| 6638 | /// instruction until the true/false value is not defined in \p Selects. | |||
| 6639 | static Value *getTrueOrFalseValue( | |||
| 6640 | SelectInst *SI, bool isTrue, | |||
| 6641 | const SmallPtrSet<const Instruction *, 2> &Selects) { | |||
| 6642 | Value *V = nullptr; | |||
| 6643 | ||||
| 6644 | for (SelectInst *DefSI = SI; DefSI != nullptr && Selects.count(DefSI); | |||
| 6645 | DefSI = dyn_cast<SelectInst>(V)) { | |||
| 6646 | assert(DefSI->getCondition() == SI->getCondition() &&((void)0) | |||
| 6647 | "The condition of DefSI does not match with SI")((void)0); | |||
| 6648 | V = (isTrue ? DefSI->getTrueValue() : DefSI->getFalseValue()); | |||
| 6649 | } | |||
| 6650 | ||||
| 6651 | assert(V && "Failed to get select true/false value")((void)0); | |||
| 6652 | return V; | |||
| 6653 | } | |||
| 6654 | ||||
| 6655 | bool CodeGenPrepare::optimizeShiftInst(BinaryOperator *Shift) { | |||
| 6656 | assert(Shift->isShift() && "Expected a shift")((void)0); | |||
| 6657 | ||||
| 6658 | // If this is (1) a vector shift, (2) shifts by scalars are cheaper than | |||
| 6659 | // general vector shifts, and (3) the shift amount is a select-of-splatted | |||
| 6660 | // values, hoist the shifts before the select: | |||
| 6661 | // shift Op0, (select Cond, TVal, FVal) --> | |||
| 6662 | // select Cond, (shift Op0, TVal), (shift Op0, FVal) | |||
| 6663 | // | |||
| 6664 | // This is inverting a generic IR transform when we know that the cost of a | |||
| 6665 | // general vector shift is more than the cost of 2 shift-by-scalars. | |||
| 6666 | // We can't do this effectively in SDAG because we may not be able to | |||
| 6667 | // determine if the select operands are splats from within a basic block. | |||
| 6668 | Type *Ty = Shift->getType(); | |||
| 6669 | if (!Ty->isVectorTy() || !TLI->isVectorShiftByScalarCheap(Ty)) | |||
| 6670 | return false; | |||
| 6671 | Value *Cond, *TVal, *FVal; | |||
| 6672 | if (!match(Shift->getOperand(1), | |||
| 6673 | m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal))))) | |||
| 6674 | return false; | |||
| 6675 | if (!isSplatValue(TVal) || !isSplatValue(FVal)) | |||
| 6676 | return false; | |||
| 6677 | ||||
| 6678 | IRBuilder<> Builder(Shift); | |||
| 6679 | BinaryOperator::BinaryOps Opcode = Shift->getOpcode(); | |||
| 6680 | Value *NewTVal = Builder.CreateBinOp(Opcode, Shift->getOperand(0), TVal); | |||
| 6681 | Value *NewFVal = Builder.CreateBinOp(Opcode, Shift->getOperand(0), FVal); | |||
| 6682 | Value *NewSel = Builder.CreateSelect(Cond, NewTVal, NewFVal); | |||
| 6683 | Shift->replaceAllUsesWith(NewSel); | |||
| 6684 | Shift->eraseFromParent(); | |||
| 6685 | return true; | |||
| 6686 | } | |||
| 6687 | ||||
| 6688 | bool CodeGenPrepare::optimizeFunnelShift(IntrinsicInst *Fsh) { | |||
| 6689 | Intrinsic::ID Opcode = Fsh->getIntrinsicID(); | |||
| 6690 | assert((Opcode == Intrinsic::fshl || Opcode == Intrinsic::fshr) &&((void)0) | |||
| 6691 | "Expected a funnel shift")((void)0); | |||
| 6692 | ||||
| 6693 | // If this is (1) a vector funnel shift, (2) shifts by scalars are cheaper | |||
| 6694 | // than general vector shifts, and (3) the shift amount is select-of-splatted | |||
| 6695 | // values, hoist the funnel shifts before the select: | |||
| 6696 | // fsh Op0, Op1, (select Cond, TVal, FVal) --> | |||
| 6697 | // select Cond, (fsh Op0, Op1, TVal), (fsh Op0, Op1, FVal) | |||
| 6698 | // | |||
| 6699 | // This is inverting a generic IR transform when we know that the cost of a | |||
| 6700 | // general vector shift is more than the cost of 2 shift-by-scalars. | |||
| 6701 | // We can't do this effectively in SDAG because we may not be able to | |||
| 6702 | // determine if the select operands are splats from within a basic block. | |||
| 6703 | Type *Ty = Fsh->getType(); | |||
| 6704 | if (!Ty->isVectorTy() || !TLI->isVectorShiftByScalarCheap(Ty)) | |||
| 6705 | return false; | |||
| 6706 | Value *Cond, *TVal, *FVal; | |||
| 6707 | if (!match(Fsh->getOperand(2), | |||
| 6708 | m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal))))) | |||
| 6709 | return false; | |||
| 6710 | if (!isSplatValue(TVal) || !isSplatValue(FVal)) | |||
| 6711 | return false; | |||
| 6712 | ||||
| 6713 | IRBuilder<> Builder(Fsh); | |||
| 6714 | Value *X = Fsh->getOperand(0), *Y = Fsh->getOperand(1); | |||
| 6715 | Value *NewTVal = Builder.CreateIntrinsic(Opcode, Ty, { X, Y, TVal }); | |||
| 6716 | Value *NewFVal = Builder.CreateIntrinsic(Opcode, Ty, { X, Y, FVal }); | |||
| 6717 | Value *NewSel = Builder.CreateSelect(Cond, NewTVal, NewFVal); | |||
| 6718 | Fsh->replaceAllUsesWith(NewSel); | |||
| 6719 | Fsh->eraseFromParent(); | |||
| 6720 | return true; | |||
| 6721 | } | |||
| 6722 | ||||
| 6723 | /// If we have a SelectInst that will likely profit from branch prediction, | |||
| 6724 | /// turn it into a branch. | |||
| 6725 | bool CodeGenPrepare::optimizeSelectInst(SelectInst *SI) { | |||
| 6726 | if (DisableSelectToBranch) | |||
| 6727 | return false; | |||
| 6728 | ||||
| 6729 | // Find all consecutive select instructions that share the same condition. | |||
| 6730 | SmallVector<SelectInst *, 2> ASI; | |||
| 6731 | ASI.push_back(SI); | |||
| 6732 | for (BasicBlock::iterator It = ++BasicBlock::iterator(SI); | |||
| 6733 | It != SI->getParent()->end(); ++It) { | |||
| 6734 | SelectInst *I = dyn_cast<SelectInst>(&*It); | |||
| 6735 | if (I && SI->getCondition() == I->getCondition()) { | |||
| 6736 | ASI.push_back(I); | |||
| 6737 | } else { | |||
| 6738 | break; | |||
| 6739 | } | |||
| 6740 | } | |||
| 6741 | ||||
| 6742 | SelectInst *LastSI = ASI.back(); | |||
| 6743 | // Increment the current iterator to skip all the rest of select instructions | |||
| 6744 | // because they will be either "not lowered" or "all lowered" to branch. | |||
| 6745 | CurInstIterator = std::next(LastSI->getIterator()); | |||
| 6746 | ||||
| 6747 | bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1); | |||
| 6748 | ||||
| 6749 | // Can we convert the 'select' to CF ? | |||
| 6750 | if (VectorCond || SI->getMetadata(LLVMContext::MD_unpredictable)) | |||
| 6751 | return false; | |||
| 6752 | ||||
| 6753 | TargetLowering::SelectSupportKind SelectKind; | |||
| 6754 | if (VectorCond) | |||
| 6755 | SelectKind = TargetLowering::VectorMaskSelect; | |||
| 6756 | else if (SI->getType()->isVectorTy()) | |||
| 6757 | SelectKind = TargetLowering::ScalarCondVectorVal; | |||
| 6758 | else | |||
| 6759 | SelectKind = TargetLowering::ScalarValSelect; | |||
| 6760 | ||||
| 6761 | if (TLI->isSelectSupported(SelectKind) && | |||
| 6762 | (!isFormingBranchFromSelectProfitable(TTI, TLI, SI) || OptSize || | |||
| 6763 | llvm::shouldOptimizeForSize(SI->getParent(), PSI, BFI.get()))) | |||
| 6764 | return false; | |||
| 6765 | ||||
| 6766 | // The DominatorTree needs to be rebuilt by any consumers after this | |||
| 6767 | // transformation. We simply reset here rather than setting the ModifiedDT | |||
| 6768 | // flag to avoid restarting the function walk in runOnFunction for each | |||
| 6769 | // select optimized. | |||
| 6770 | DT.reset(); | |||
| 6771 | ||||
| 6772 | // Transform a sequence like this: | |||
| 6773 | // start: | |||
| 6774 | // %cmp = cmp uge i32 %a, %b | |||
| 6775 | // %sel = select i1 %cmp, i32 %c, i32 %d | |||
| 6776 | // | |||
| 6777 | // Into: | |||
| 6778 | // start: | |||
| 6779 | // %cmp = cmp uge i32 %a, %b | |||
| 6780 | // %cmp.frozen = freeze %cmp | |||
| 6781 | // br i1 %cmp.frozen, label %select.true, label %select.false | |||
| 6782 | // select.true: | |||
| 6783 | // br label %select.end | |||
| 6784 | // select.false: | |||
| 6785 | // br label %select.end | |||
| 6786 | // select.end: | |||
| 6787 | // %sel = phi i32 [ %c, %select.true ], [ %d, %select.false ] | |||
| 6788 | // | |||
| 6789 | // %cmp should be frozen, otherwise it may introduce undefined behavior. | |||
| 6790 | // In addition, we may sink instructions that produce %c or %d from | |||
| 6791 | // the entry block into the destination(s) of the new branch. | |||
| 6792 | // If the true or false blocks do not contain a sunken instruction, that | |||
| 6793 | // block and its branch may be optimized away. In that case, one side of the | |||
| 6794 | // first branch will point directly to select.end, and the corresponding PHI | |||
| 6795 | // predecessor block will be the start block. | |||
| 6796 | ||||
| 6797 | // First, we split the block containing the select into 2 blocks. | |||
| 6798 | BasicBlock *StartBlock = SI->getParent(); | |||
| 6799 | BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(LastSI)); | |||
| 6800 | BasicBlock *EndBlock = StartBlock->splitBasicBlock(SplitPt, "select.end"); | |||
| 6801 | BFI->setBlockFreq(EndBlock, BFI->getBlockFreq(StartBlock).getFrequency()); | |||
| 6802 | ||||
| 6803 | // Delete the unconditional branch that was just created by the split. | |||
| 6804 | StartBlock->getTerminator()->eraseFromParent(); | |||
| 6805 | ||||
| 6806 | // These are the new basic blocks for the conditional branch. | |||
| 6807 | // At least one will become an actual new basic block. | |||
| 6808 | BasicBlock *TrueBlock = nullptr; | |||
| 6809 | BasicBlock *FalseBlock = nullptr; | |||
| 6810 | BranchInst *TrueBranch = nullptr; | |||
| 6811 | BranchInst *FalseBranch = nullptr; | |||
| 6812 | ||||
| 6813 | // Sink expensive instructions into the conditional blocks to avoid executing | |||
| 6814 | // them speculatively. | |||
| 6815 | for (SelectInst *SI : ASI) { | |||
| 6816 | if (sinkSelectOperand(TTI, SI->getTrueValue())) { | |||
| 6817 | if (TrueBlock == nullptr) { | |||
| 6818 | TrueBlock = BasicBlock::Create(SI->getContext(), "select.true.sink", | |||
| 6819 | EndBlock->getParent(), EndBlock); | |||
| 6820 | TrueBranch = BranchInst::Create(EndBlock, TrueBlock); | |||
| 6821 | TrueBranch->setDebugLoc(SI->getDebugLoc()); | |||
| 6822 | } | |||
| 6823 | auto *TrueInst = cast<Instruction>(SI->getTrueValue()); | |||
| 6824 | TrueInst->moveBefore(TrueBranch); | |||
| 6825 | } | |||
| 6826 | if (sinkSelectOperand(TTI, SI->getFalseValue())) { | |||
| 6827 | if (FalseBlock == nullptr) { | |||
| 6828 | FalseBlock = BasicBlock::Create(SI->getContext(), "select.false.sink", | |||
| 6829 | EndBlock->getParent(), EndBlock); | |||
| 6830 | FalseBranch = BranchInst::Create(EndBlock, FalseBlock); | |||
| 6831 | FalseBranch->setDebugLoc(SI->getDebugLoc()); | |||
| 6832 | } | |||
| 6833 | auto *FalseInst = cast<Instruction>(SI->getFalseValue()); | |||
| 6834 | FalseInst->moveBefore(FalseBranch); | |||
| 6835 | } | |||
| 6836 | } | |||
| 6837 | ||||
| 6838 | // If there was nothing to sink, then arbitrarily choose the 'false' side | |||
| 6839 | // for a new input value to the PHI. | |||
| 6840 | if (TrueBlock == FalseBlock) { | |||
| 6841 | assert(TrueBlock == nullptr &&((void)0) | |||
| 6842 | "Unexpected basic block transform while optimizing select")((void)0); | |||
| 6843 | ||||
| 6844 | FalseBlock = BasicBlock::Create(SI->getContext(), "select.false", | |||
| 6845 | EndBlock->getParent(), EndBlock); | |||
| 6846 | auto *FalseBranch = BranchInst::Create(EndBlock, FalseBlock); | |||
| 6847 | FalseBranch->setDebugLoc(SI->getDebugLoc()); | |||
| 6848 | } | |||
| 6849 | ||||
| 6850 | // Insert the real conditional branch based on the original condition. | |||
| 6851 | // If we did not create a new block for one of the 'true' or 'false' paths | |||
| 6852 | // of the condition, it means that side of the branch goes to the end block | |||
| 6853 | // directly and the path originates from the start block from the point of | |||
| 6854 | // view of the new PHI. | |||
| 6855 | BasicBlock *TT, *FT; | |||
| 6856 | if (TrueBlock == nullptr) { | |||
| 6857 | TT = EndBlock; | |||
| 6858 | FT = FalseBlock; | |||
| 6859 | TrueBlock = StartBlock; | |||
| 6860 | } else if (FalseBlock == nullptr) { | |||
| 6861 | TT = TrueBlock; | |||
| 6862 | FT = EndBlock; | |||
| 6863 | FalseBlock = StartBlock; | |||
| 6864 | } else { | |||
| 6865 | TT = TrueBlock; | |||
| 6866 | FT = FalseBlock; | |||
| 6867 | } | |||
| 6868 | IRBuilder<> IB(SI); | |||
| 6869 | auto *CondFr = IB.CreateFreeze(SI->getCondition(), SI->getName() + ".frozen"); | |||
| 6870 | IB.CreateCondBr(CondFr, TT, FT, SI); | |||
| 6871 | ||||
| 6872 | SmallPtrSet<const Instruction *, 2> INS; | |||
| 6873 | INS.insert(ASI.begin(), ASI.end()); | |||
| 6874 | // Use reverse iterator because later select may use the value of the | |||
| 6875 | // earlier select, and we need to propagate value through earlier select | |||
| 6876 | // to get the PHI operand. | |||
| 6877 | for (auto It = ASI.rbegin(); It != ASI.rend(); ++It) { | |||
| 6878 | SelectInst *SI = *It; | |||
| 6879 | // The select itself is replaced with a PHI Node. | |||
| 6880 | PHINode *PN = PHINode::Create(SI->getType(), 2, "", &EndBlock->front()); | |||
| 6881 | PN->takeName(SI); | |||
| 6882 | PN->addIncoming(getTrueOrFalseValue(SI, true, INS), TrueBlock); | |||
| 6883 | PN->addIncoming(getTrueOrFalseValue(SI, false, INS), FalseBlock); | |||
| 6884 | PN->setDebugLoc(SI->getDebugLoc()); | |||
| 6885 | ||||
| 6886 | SI->replaceAllUsesWith(PN); | |||
| 6887 | SI->eraseFromParent(); | |||
| 6888 | INS.erase(SI); | |||
| 6889 | ++NumSelectsExpanded; | |||
| 6890 | } | |||
| 6891 | ||||
| 6892 | // Instruct OptimizeBlock to skip to the next block. | |||
| 6893 | CurInstIterator = StartBlock->end(); | |||
| 6894 | return true; | |||
| 6895 | } | |||
| 6896 | ||||
| 6897 | /// Some targets only accept certain types for splat inputs. For example a VDUP | |||
| 6898 | /// in MVE takes a GPR (integer) register, and the instruction that incorporate | |||
| 6899 | /// a VDUP (such as a VADD qd, qm, rm) also require a gpr register. | |||
| 6900 | bool CodeGenPrepare::optimizeShuffleVectorInst(ShuffleVectorInst *SVI) { | |||
| 6901 | // Accept shuf(insertelem(undef/poison, val, 0), undef/poison, <0,0,..>) only | |||
| 6902 | if (!match(SVI, m_Shuffle(m_InsertElt(m_Undef(), m_Value(), m_ZeroInt()), | |||
| 6903 | m_Undef(), m_ZeroMask()))) | |||
| 6904 | return false; | |||
| 6905 | Type *NewType = TLI->shouldConvertSplatType(SVI); | |||
| 6906 | if (!NewType) | |||
| 6907 | return false; | |||
| 6908 | ||||
| 6909 | auto *SVIVecType = cast<FixedVectorType>(SVI->getType()); | |||
| 6910 | assert(!NewType->isVectorTy() && "Expected a scalar type!")((void)0); | |||
| 6911 | assert(NewType->getScalarSizeInBits() == SVIVecType->getScalarSizeInBits() &&((void)0) | |||
| 6912 | "Expected a type of the same size!")((void)0); | |||
| 6913 | auto *NewVecType = | |||
| 6914 | FixedVectorType::get(NewType, SVIVecType->getNumElements()); | |||
| 6915 | ||||
| 6916 | // Create a bitcast (shuffle (insert (bitcast(..)))) | |||
| 6917 | IRBuilder<> Builder(SVI->getContext()); | |||
| 6918 | Builder.SetInsertPoint(SVI); | |||
| 6919 | Value *BC1 = Builder.CreateBitCast( | |||
| 6920 | cast<Instruction>(SVI->getOperand(0))->getOperand(1), NewType); | |||
| 6921 | Value *Shuffle = Builder.CreateVectorSplat(NewVecType->getNumElements(), BC1); | |||
| 6922 | Value *BC2 = Builder.CreateBitCast(Shuffle, SVIVecType); | |||
| 6923 | ||||
| 6924 | SVI->replaceAllUsesWith(BC2); | |||
| 6925 | RecursivelyDeleteTriviallyDeadInstructions( | |||
| 6926 | SVI, TLInfo, nullptr, [&](Value *V) { removeAllAssertingVHReferences(V); }); | |||
| 6927 | ||||
| 6928 | // Also hoist the bitcast up to its operand if it they are not in the same | |||
| 6929 | // block. | |||
| 6930 | if (auto *BCI = dyn_cast<Instruction>(BC1)) | |||
| 6931 | if (auto *Op = dyn_cast<Instruction>(BCI->getOperand(0))) | |||
| 6932 | if (BCI->getParent() != Op->getParent() && !isa<PHINode>(Op) && | |||
| 6933 | !Op->isTerminator() && !Op->isEHPad()) | |||
| 6934 | BCI->moveAfter(Op); | |||
| 6935 | ||||
| 6936 | return true; | |||
| 6937 | } | |||
| 6938 | ||||
| 6939 | bool CodeGenPrepare::tryToSinkFreeOperands(Instruction *I) { | |||
| 6940 | // If the operands of I can be folded into a target instruction together with | |||
| 6941 | // I, duplicate and sink them. | |||
| 6942 | SmallVector<Use *, 4> OpsToSink; | |||
| 6943 | if (!TLI->shouldSinkOperands(I, OpsToSink)) | |||
| 6944 | return false; | |||
| 6945 | ||||
| 6946 | // OpsToSink can contain multiple uses in a use chain (e.g. | |||
| 6947 | // (%u1 with %u1 = shufflevector), (%u2 with %u2 = zext %u1)). The dominating | |||
| 6948 | // uses must come first, so we process the ops in reverse order so as to not | |||
| 6949 | // create invalid IR. | |||
| 6950 | BasicBlock *TargetBB = I->getParent(); | |||
| 6951 | bool Changed = false; | |||
| 6952 | SmallVector<Use *, 4> ToReplace; | |||
| 6953 | for (Use *U : reverse(OpsToSink)) { | |||
| 6954 | auto *UI = cast<Instruction>(U->get()); | |||
| 6955 | if (UI->getParent() == TargetBB || isa<PHINode>(UI)) | |||
| 6956 | continue; | |||
| 6957 | ToReplace.push_back(U); | |||
| 6958 | } | |||
| 6959 | ||||
| 6960 | SetVector<Instruction *> MaybeDead; | |||
| 6961 | DenseMap<Instruction *, Instruction *> NewInstructions; | |||
| 6962 | Instruction *InsertPoint = I; | |||
| 6963 | for (Use *U : ToReplace) { | |||
| 6964 | auto *UI = cast<Instruction>(U->get()); | |||
| 6965 | Instruction *NI = UI->clone(); | |||
| 6966 | NewInstructions[UI] = NI; | |||
| 6967 | MaybeDead.insert(UI); | |||
| 6968 | LLVM_DEBUG(dbgs() << "Sinking " << *UI << " to user " << *I << "\n")do { } while (false); | |||
| 6969 | NI->insertBefore(InsertPoint); | |||
| 6970 | InsertPoint = NI; | |||
| 6971 | InsertedInsts.insert(NI); | |||
| 6972 | ||||
| 6973 | // Update the use for the new instruction, making sure that we update the | |||
| 6974 | // sunk instruction uses, if it is part of a chain that has already been | |||
| 6975 | // sunk. | |||
| 6976 | Instruction *OldI = cast<Instruction>(U->getUser()); | |||
| 6977 | if (NewInstructions.count(OldI)) | |||
| 6978 | NewInstructions[OldI]->setOperand(U->getOperandNo(), NI); | |||
| 6979 | else | |||
| 6980 | U->set(NI); | |||
| 6981 | Changed = true; | |||
| 6982 | } | |||
| 6983 | ||||
| 6984 | // Remove instructions that are dead after sinking. | |||
| 6985 | for (auto *I : MaybeDead) { | |||
| 6986 | if (!I->hasNUsesOrMore(1)) { | |||
| 6987 | LLVM_DEBUG(dbgs() << "Removing dead instruction: " << *I << "\n")do { } while (false); | |||
| 6988 | I->eraseFromParent(); | |||
| 6989 | } | |||
| 6990 | } | |||
| 6991 | ||||
| 6992 | return Changed; | |||
| 6993 | } | |||
| 6994 | ||||
| 6995 | bool CodeGenPrepare::optimizeSwitchInst(SwitchInst *SI) { | |||
| 6996 | Value *Cond = SI->getCondition(); | |||
| 6997 | Type *OldType = Cond->getType(); | |||
| 6998 | LLVMContext &Context = Cond->getContext(); | |||
| 6999 | EVT OldVT = TLI->getValueType(*DL, OldType); | |||
| 7000 | MVT RegType = TLI->getRegisterType(Context, OldVT); | |||
| 7001 | unsigned RegWidth = RegType.getSizeInBits(); | |||
| 7002 | ||||
| 7003 | if (RegWidth <= cast<IntegerType>(OldType)->getBitWidth()) | |||
| 7004 | return false; | |||
| 7005 | ||||
| 7006 | // If the register width is greater than the type width, expand the condition | |||
| 7007 | // of the switch instruction and each case constant to the width of the | |||
| 7008 | // register. By widening the type of the switch condition, subsequent | |||
| 7009 | // comparisons (for case comparisons) will not need to be extended to the | |||
| 7010 | // preferred register width, so we will potentially eliminate N-1 extends, | |||
| 7011 | // where N is the number of cases in the switch. | |||
| 7012 | auto *NewType = Type::getIntNTy(Context, RegWidth); | |||
| 7013 | ||||
| 7014 | // Extend the switch condition and case constants using the target preferred | |||
| 7015 | // extend unless the switch condition is a function argument with an extend | |||
| 7016 | // attribute. In that case, we can avoid an unnecessary mask/extension by | |||
| 7017 | // matching the argument extension instead. | |||
| 7018 | Instruction::CastOps ExtType = Instruction::ZExt; | |||
| 7019 | // Some targets prefer SExt over ZExt. | |||
| 7020 | if (TLI->isSExtCheaperThanZExt(OldVT, RegType)) | |||
| 7021 | ExtType = Instruction::SExt; | |||
| 7022 | ||||
| 7023 | if (auto *Arg = dyn_cast<Argument>(Cond)) { | |||
| 7024 | if (Arg->hasSExtAttr()) | |||
| 7025 | ExtType = Instruction::SExt; | |||
| 7026 | if (Arg->hasZExtAttr()) | |||
| 7027 | ExtType = Instruction::ZExt; | |||
| 7028 | } | |||
| 7029 | ||||
| 7030 | auto *ExtInst = CastInst::Create(ExtType, Cond, NewType); | |||
| 7031 | ExtInst->insertBefore(SI); | |||
| 7032 | ExtInst->setDebugLoc(SI->getDebugLoc()); | |||
| 7033 | SI->setCondition(ExtInst); | |||
| 7034 | for (auto Case : SI->cases()) { | |||
| 7035 | APInt NarrowConst = Case.getCaseValue()->getValue(); | |||
| 7036 | APInt WideConst = (ExtType == Instruction::ZExt) ? | |||
| 7037 | NarrowConst.zext(RegWidth) : NarrowConst.sext(RegWidth); | |||
| 7038 | Case.setValue(ConstantInt::get(Context, WideConst)); | |||
| 7039 | } | |||
| 7040 | ||||
| 7041 | return true; | |||
| 7042 | } | |||
| 7043 | ||||
| 7044 | ||||
| 7045 | namespace { | |||
| 7046 | ||||
| 7047 | /// Helper class to promote a scalar operation to a vector one. | |||
| 7048 | /// This class is used to move downward extractelement transition. | |||
| 7049 | /// E.g., | |||
| 7050 | /// a = vector_op <2 x i32> | |||
| 7051 | /// b = extractelement <2 x i32> a, i32 0 | |||
| 7052 | /// c = scalar_op b | |||
| 7053 | /// store c | |||
| 7054 | /// | |||
| 7055 | /// => | |||
| 7056 | /// a = vector_op <2 x i32> | |||
| 7057 | /// c = vector_op a (equivalent to scalar_op on the related lane) | |||
| 7058 | /// * d = extractelement <2 x i32> c, i32 0 | |||
| 7059 | /// * store d | |||
| 7060 | /// Assuming both extractelement and store can be combine, we get rid of the | |||
| 7061 | /// transition. | |||
| 7062 | class VectorPromoteHelper { | |||
| 7063 | /// DataLayout associated with the current module. | |||
| 7064 | const DataLayout &DL; | |||
| 7065 | ||||
| 7066 | /// Used to perform some checks on the legality of vector operations. | |||
| 7067 | const TargetLowering &TLI; | |||
| 7068 | ||||
| 7069 | /// Used to estimated the cost of the promoted chain. | |||
| 7070 | const TargetTransformInfo &TTI; | |||
| 7071 | ||||
| 7072 | /// The transition being moved downwards. | |||
| 7073 | Instruction *Transition; | |||
| 7074 | ||||
| 7075 | /// The sequence of instructions to be promoted. | |||
| 7076 | SmallVector<Instruction *, 4> InstsToBePromoted; | |||
| 7077 | ||||
| 7078 | /// Cost of combining a store and an extract. | |||
| 7079 | unsigned StoreExtractCombineCost; | |||
| 7080 | ||||
| 7081 | /// Instruction that will be combined with the transition. | |||
| 7082 | Instruction *CombineInst = nullptr; | |||
| 7083 | ||||
| 7084 | /// The instruction that represents the current end of the transition. | |||
| 7085 | /// Since we are faking the promotion until we reach the end of the chain | |||
| 7086 | /// of computation, we need a way to get the current end of the transition. | |||
| 7087 | Instruction *getEndOfTransition() const { | |||
| 7088 | if (InstsToBePromoted.empty()) | |||
| 7089 | return Transition; | |||
| 7090 | return InstsToBePromoted.back(); | |||
| 7091 | } | |||
| 7092 | ||||
| 7093 | /// Return the index of the original value in the transition. | |||
| 7094 | /// E.g., for "extractelement <2 x i32> c, i32 1" the original value, | |||
| 7095 | /// c, is at index 0. | |||
| 7096 | unsigned getTransitionOriginalValueIdx() const { | |||
| 7097 | assert(isa<ExtractElementInst>(Transition) &&((void)0) | |||
| 7098 | "Other kind of transitions are not supported yet")((void)0); | |||
| 7099 | return 0; | |||
| 7100 | } | |||
| 7101 | ||||
| 7102 | /// Return the index of the index in the transition. | |||
| 7103 | /// E.g., for "extractelement <2 x i32> c, i32 0" the index | |||
| 7104 | /// is at index 1. | |||
| 7105 | unsigned getTransitionIdx() const { | |||
| 7106 | assert(isa<ExtractElementInst>(Transition) &&((void)0) | |||
| 7107 | "Other kind of transitions are not supported yet")((void)0); | |||
| 7108 | return 1; | |||
| 7109 | } | |||
| 7110 | ||||
| 7111 | /// Get the type of the transition. | |||
| 7112 | /// This is the type of the original value. | |||
| 7113 | /// E.g., for "extractelement <2 x i32> c, i32 1" the type of the | |||
| 7114 | /// transition is <2 x i32>. | |||
| 7115 | Type *getTransitionType() const { | |||
| 7116 | return Transition->getOperand(getTransitionOriginalValueIdx())->getType(); | |||
| 7117 | } | |||
| 7118 | ||||
| 7119 | /// Promote \p ToBePromoted by moving \p Def downward through. | |||
| 7120 | /// I.e., we have the following sequence: | |||
| 7121 | /// Def = Transition <ty1> a to <ty2> | |||
| 7122 | /// b = ToBePromoted <ty2> Def, ... | |||
| 7123 | /// => | |||
| 7124 | /// b = ToBePromoted <ty1> a, ... | |||
| 7125 | /// Def = Transition <ty1> ToBePromoted to <ty2> | |||
| 7126 | void promoteImpl(Instruction *ToBePromoted); | |||
| 7127 | ||||
| 7128 | /// Check whether or not it is profitable to promote all the | |||
| 7129 | /// instructions enqueued to be promoted. | |||
| 7130 | bool isProfitableToPromote() { | |||
| 7131 | Value *ValIdx = Transition->getOperand(getTransitionOriginalValueIdx()); | |||
| 7132 | unsigned Index = isa<ConstantInt>(ValIdx) | |||
| 7133 | ? cast<ConstantInt>(ValIdx)->getZExtValue() | |||
| 7134 | : -1; | |||
| 7135 | Type *PromotedType = getTransitionType(); | |||
| 7136 | ||||
| 7137 | StoreInst *ST = cast<StoreInst>(CombineInst); | |||
| 7138 | unsigned AS = ST->getPointerAddressSpace(); | |||
| 7139 | // Check if this store is supported. | |||
| 7140 | if (!TLI.allowsMisalignedMemoryAccesses( | |||
| 7141 | TLI.getValueType(DL, ST->getValueOperand()->getType()), AS, | |||
| 7142 | ST->getAlign())) { | |||
| 7143 | // If this is not supported, there is no way we can combine | |||
| 7144 | // the extract with the store. | |||
| 7145 | return false; | |||
| 7146 | } | |||
| 7147 | ||||
| 7148 | // The scalar chain of computation has to pay for the transition | |||
| 7149 | // scalar to vector. | |||
| 7150 | // The vector chain has to account for the combining cost. | |||
| 7151 | InstructionCost ScalarCost = | |||
| 7152 | TTI.getVectorInstrCost(Transition->getOpcode(), PromotedType, Index); | |||
| 7153 | InstructionCost VectorCost = StoreExtractCombineCost; | |||
| 7154 | enum TargetTransformInfo::TargetCostKind CostKind = | |||
| 7155 | TargetTransformInfo::TCK_RecipThroughput; | |||
| 7156 | for (const auto &Inst : InstsToBePromoted) { | |||
| 7157 | // Compute the cost. | |||
| 7158 | // By construction, all instructions being promoted are arithmetic ones. | |||
| 7159 | // Moreover, one argument is a constant that can be viewed as a splat | |||
| 7160 | // constant. | |||
| 7161 | Value *Arg0 = Inst->getOperand(0); | |||
| 7162 | bool IsArg0Constant = isa<UndefValue>(Arg0) || isa<ConstantInt>(Arg0) || | |||
| 7163 | isa<ConstantFP>(Arg0); | |||
| 7164 | TargetTransformInfo::OperandValueKind Arg0OVK = | |||
| 7165 | IsArg0Constant ? TargetTransformInfo::OK_UniformConstantValue | |||
| 7166 | : TargetTransformInfo::OK_AnyValue; | |||
| 7167 | TargetTransformInfo::OperandValueKind Arg1OVK = | |||
| 7168 | !IsArg0Constant ? TargetTransformInfo::OK_UniformConstantValue | |||
| 7169 | : TargetTransformInfo::OK_AnyValue; | |||
| 7170 | ScalarCost += TTI.getArithmeticInstrCost( | |||
| 7171 | Inst->getOpcode(), Inst->getType(), CostKind, Arg0OVK, Arg1OVK); | |||
| 7172 | VectorCost += TTI.getArithmeticInstrCost(Inst->getOpcode(), PromotedType, | |||
| 7173 | CostKind, | |||
| 7174 | Arg0OVK, Arg1OVK); | |||
| 7175 | } | |||
| 7176 | LLVM_DEBUG(do { } while (false) | |||
| 7177 | dbgs() << "Estimated cost of computation to be promoted:\nScalar: "do { } while (false) | |||
| 7178 | << ScalarCost << "\nVector: " << VectorCost << '\n')do { } while (false); | |||
| 7179 | return ScalarCost > VectorCost; | |||
| 7180 | } | |||
| 7181 | ||||
| 7182 | /// Generate a constant vector with \p Val with the same | |||
| 7183 | /// number of elements as the transition. | |||
| 7184 | /// \p UseSplat defines whether or not \p Val should be replicated | |||
| 7185 | /// across the whole vector. | |||
| 7186 | /// In other words, if UseSplat == true, we generate <Val, Val, ..., Val>, | |||
| 7187 | /// otherwise we generate a vector with as many undef as possible: | |||
| 7188 | /// <undef, ..., undef, Val, undef, ..., undef> where \p Val is only | |||
| 7189 | /// used at the index of the extract. | |||
| 7190 | Value *getConstantVector(Constant *Val, bool UseSplat) const { | |||
| 7191 | unsigned ExtractIdx = std::numeric_limits<unsigned>::max(); | |||
| 7192 | if (!UseSplat) { | |||
| 7193 | // If we cannot determine where the constant must be, we have to | |||
| 7194 | // use a splat constant. | |||
| 7195 | Value *ValExtractIdx = Transition->getOperand(getTransitionIdx()); | |||
| 7196 | if (ConstantInt *CstVal = dyn_cast<ConstantInt>(ValExtractIdx)) | |||
| 7197 | ExtractIdx = CstVal->getSExtValue(); | |||
| 7198 | else | |||
| 7199 | UseSplat = true; | |||
| 7200 | } | |||
| 7201 | ||||
| 7202 | ElementCount EC = cast<VectorType>(getTransitionType())->getElementCount(); | |||
| 7203 | if (UseSplat) | |||
| 7204 | return ConstantVector::getSplat(EC, Val); | |||
| 7205 | ||||
| 7206 | if (!EC.isScalable()) { | |||
| 7207 | SmallVector<Constant *, 4> ConstVec; | |||
| 7208 | UndefValue *UndefVal = UndefValue::get(Val->getType()); | |||
| 7209 | for (unsigned Idx = 0; Idx != EC.getKnownMinValue(); ++Idx) { | |||
| 7210 | if (Idx == ExtractIdx) | |||
| 7211 | ConstVec.push_back(Val); | |||
| 7212 | else | |||
| 7213 | ConstVec.push_back(UndefVal); | |||
| 7214 | } | |||
| 7215 | return ConstantVector::get(ConstVec); | |||
| 7216 | } else | |||
| 7217 | llvm_unreachable(__builtin_unreachable() | |||
| 7218 | "Generate scalable vector for non-splat is unimplemented")__builtin_unreachable(); | |||
| 7219 | } | |||
| 7220 | ||||
| 7221 | /// Check if promoting to a vector type an operand at \p OperandIdx | |||
| 7222 | /// in \p Use can trigger undefined behavior. | |||
| 7223 | static bool canCauseUndefinedBehavior(const Instruction *Use, | |||
| 7224 | unsigned OperandIdx) { | |||
| 7225 | // This is not safe to introduce undef when the operand is on | |||
| 7226 | // the right hand side of a division-like instruction. | |||
| 7227 | if (OperandIdx != 1) | |||
| 7228 | return false; | |||
| 7229 | switch (Use->getOpcode()) { | |||
| 7230 | default: | |||
| 7231 | return false; | |||
| 7232 | case Instruction::SDiv: | |||
| 7233 | case Instruction::UDiv: | |||
| 7234 | case Instruction::SRem: | |||
| 7235 | case Instruction::URem: | |||
| 7236 | return true; | |||
| 7237 | case Instruction::FDiv: | |||
| 7238 | case Instruction::FRem: | |||
| 7239 | return !Use->hasNoNaNs(); | |||
| 7240 | } | |||
| 7241 | llvm_unreachable(nullptr)__builtin_unreachable(); | |||
| 7242 | } | |||
| 7243 | ||||
| 7244 | public: | |||
| 7245 | VectorPromoteHelper(const DataLayout &DL, const TargetLowering &TLI, | |||
| 7246 | const TargetTransformInfo &TTI, Instruction *Transition, | |||
| 7247 | unsigned CombineCost) | |||
| 7248 | : DL(DL), TLI(TLI), TTI(TTI), Transition(Transition), | |||
| 7249 | StoreExtractCombineCost(CombineCost) { | |||
| 7250 | assert(Transition && "Do not know how to promote null")((void)0); | |||
| 7251 | } | |||
| 7252 | ||||
| 7253 | /// Check if we can promote \p ToBePromoted to \p Type. | |||
| 7254 | bool canPromote(const Instruction *ToBePromoted) const { | |||
| 7255 | // We could support CastInst too. | |||
| 7256 | return isa<BinaryOperator>(ToBePromoted); | |||
| 7257 | } | |||
| 7258 | ||||
| 7259 | /// Check if it is profitable to promote \p ToBePromoted | |||
| 7260 | /// by moving downward the transition through. | |||
| 7261 | bool shouldPromote(const Instruction *ToBePromoted) const { | |||
| 7262 | // Promote only if all the operands can be statically expanded. | |||
| 7263 | // Indeed, we do not want to introduce any new kind of transitions. | |||
| 7264 | for (const Use &U : ToBePromoted->operands()) { | |||
| 7265 | const Value *Val = U.get(); | |||
| 7266 | if (Val == getEndOfTransition()) { | |||
| 7267 | // If the use is a division and the transition is on the rhs, | |||
| 7268 | // we cannot promote the operation, otherwise we may create a | |||
| 7269 | // division by zero. | |||
| 7270 | if (canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo())) | |||
| 7271 | return false; | |||
| 7272 | continue; | |||
| 7273 | } | |||
| 7274 | if (!isa<ConstantInt>(Val) && !isa<UndefValue>(Val) && | |||
| 7275 | !isa<ConstantFP>(Val)) | |||
| 7276 | return false; | |||
| 7277 | } | |||
| 7278 | // Check that the resulting operation is legal. | |||
| 7279 | int ISDOpcode = TLI.InstructionOpcodeToISD(ToBePromoted->getOpcode()); | |||
| 7280 | if (!ISDOpcode) | |||
| 7281 | return false; | |||
| 7282 | return StressStoreExtract || | |||
| 7283 | TLI.isOperationLegalOrCustom( | |||
| 7284 | ISDOpcode, TLI.getValueType(DL, getTransitionType(), true)); | |||
| 7285 | } | |||
| 7286 | ||||
| 7287 | /// Check whether or not \p Use can be combined | |||
| 7288 | /// with the transition. | |||
| 7289 | /// I.e., is it possible to do Use(Transition) => AnotherUse? | |||
| 7290 | bool canCombine(const Instruction *Use) { return isa<StoreInst>(Use); } | |||
| 7291 | ||||
| 7292 | /// Record \p ToBePromoted as part of the chain to be promoted. | |||
| 7293 | void enqueueForPromotion(Instruction *ToBePromoted) { | |||
| 7294 | InstsToBePromoted.push_back(ToBePromoted); | |||
| 7295 | } | |||
| 7296 | ||||
| 7297 | /// Set the instruction that will be combined with the transition. | |||
| 7298 | void recordCombineInstruction(Instruction *ToBeCombined) { | |||
| 7299 | assert(canCombine(ToBeCombined) && "Unsupported instruction to combine")((void)0); | |||
| 7300 | CombineInst = ToBeCombined; | |||
| 7301 | } | |||
| 7302 | ||||
| 7303 | /// Promote all the instructions enqueued for promotion if it is | |||
| 7304 | /// is profitable. | |||
| 7305 | /// \return True if the promotion happened, false otherwise. | |||
| 7306 | bool promote() { | |||
| 7307 | // Check if there is something to promote. | |||
| 7308 | // Right now, if we do not have anything to combine with, | |||
| 7309 | // we assume the promotion is not profitable. | |||
| 7310 | if (InstsToBePromoted.empty() || !CombineInst) | |||
| 7311 | return false; | |||
| 7312 | ||||
| 7313 | // Check cost. | |||
| 7314 | if (!StressStoreExtract && !isProfitableToPromote()) | |||
| 7315 | return false; | |||
| 7316 | ||||
| 7317 | // Promote. | |||
| 7318 | for (auto &ToBePromoted : InstsToBePromoted) | |||
| 7319 | promoteImpl(ToBePromoted); | |||
| 7320 | InstsToBePromoted.clear(); | |||
| 7321 | return true; | |||
| 7322 | } | |||
| 7323 | }; | |||
| 7324 | ||||
| 7325 | } // end anonymous namespace | |||
| 7326 | ||||
| 7327 | void VectorPromoteHelper::promoteImpl(Instruction *ToBePromoted) { | |||
| 7328 | // At this point, we know that all the operands of ToBePromoted but Def | |||
| 7329 | // can be statically promoted. | |||
| 7330 | // For Def, we need to use its parameter in ToBePromoted: | |||
| 7331 | // b = ToBePromoted ty1 a | |||
| 7332 | // Def = Transition ty1 b to ty2 | |||
| 7333 | // Move the transition down. | |||
| 7334 | // 1. Replace all uses of the promoted operation by the transition. | |||
| 7335 | // = ... b => = ... Def. | |||
| 7336 | assert(ToBePromoted->getType() == Transition->getType() &&((void)0) | |||
| 7337 | "The type of the result of the transition does not match "((void)0) | |||
| 7338 | "the final type")((void)0); | |||
| 7339 | ToBePromoted->replaceAllUsesWith(Transition); | |||
| 7340 | // 2. Update the type of the uses. | |||
| 7341 | // b = ToBePromoted ty2 Def => b = ToBePromoted ty1 Def. | |||
| 7342 | Type *TransitionTy = getTransitionType(); | |||
| 7343 | ToBePromoted->mutateType(TransitionTy); | |||
| 7344 | // 3. Update all the operands of the promoted operation with promoted | |||
| 7345 | // operands. | |||
| 7346 | // b = ToBePromoted ty1 Def => b = ToBePromoted ty1 a. | |||
| 7347 | for (Use &U : ToBePromoted->operands()) { | |||
| 7348 | Value *Val = U.get(); | |||
| 7349 | Value *NewVal = nullptr; | |||
| 7350 | if (Val == Transition) | |||
| 7351 | NewVal = Transition->getOperand(getTransitionOriginalValueIdx()); | |||
| 7352 | else if (isa<UndefValue>(Val) || isa<ConstantInt>(Val) || | |||
| 7353 | isa<ConstantFP>(Val)) { | |||
| 7354 | // Use a splat constant if it is not safe to use undef. | |||
| 7355 | NewVal = getConstantVector( | |||
| 7356 | cast<Constant>(Val), | |||
| 7357 | isa<UndefValue>(Val) || | |||
| 7358 | canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo())); | |||
| 7359 | } else | |||
| 7360 | llvm_unreachable("Did you modified shouldPromote and forgot to update "__builtin_unreachable() | |||
| 7361 | "this?")__builtin_unreachable(); | |||
| 7362 | ToBePromoted->setOperand(U.getOperandNo(), NewVal); | |||
| 7363 | } | |||
| 7364 | Transition->moveAfter(ToBePromoted); | |||
| 7365 | Transition->setOperand(getTransitionOriginalValueIdx(), ToBePromoted); | |||
| 7366 | } | |||
| 7367 | ||||
| 7368 | /// Some targets can do store(extractelement) with one instruction. | |||
| 7369 | /// Try to push the extractelement towards the stores when the target | |||
| 7370 | /// has this feature and this is profitable. | |||
| 7371 | bool CodeGenPrepare::optimizeExtractElementInst(Instruction *Inst) { | |||
| 7372 | unsigned CombineCost = std::numeric_limits<unsigned>::max(); | |||
| 7373 | if (DisableStoreExtract || | |||
| 7374 | (!StressStoreExtract && | |||
| 7375 | !TLI->canCombineStoreAndExtract(Inst->getOperand(0)->getType(), | |||
| 7376 | Inst->getOperand(1), CombineCost))) | |||
| 7377 | return false; | |||
| 7378 | ||||
| 7379 | // At this point we know that Inst is a vector to scalar transition. | |||
| 7380 | // Try to move it down the def-use chain, until: | |||
| 7381 | // - We can combine the transition with its single use | |||
| 7382 | // => we got rid of the transition. | |||
| 7383 | // - We escape the current basic block | |||
| 7384 | // => we would need to check that we are moving it at a cheaper place and | |||
| 7385 | // we do not do that for now. | |||
| 7386 | BasicBlock *Parent = Inst->getParent(); | |||
| 7387 | LLVM_DEBUG(dbgs() << "Found an interesting transition: " << *Inst << '\n')do { } while (false); | |||
| 7388 | VectorPromoteHelper VPH(*DL, *TLI, *TTI, Inst, CombineCost); | |||
| 7389 | // If the transition has more than one use, assume this is not going to be | |||
| 7390 | // beneficial. | |||
| 7391 | while (Inst->hasOneUse()) { | |||
| 7392 | Instruction *ToBePromoted = cast<Instruction>(*Inst->user_begin()); | |||
| 7393 | LLVM_DEBUG(dbgs() << "Use: " << *ToBePromoted << '\n')do { } while (false); | |||
| 7394 | ||||
| 7395 | if (ToBePromoted->getParent() != Parent) { | |||
| 7396 | LLVM_DEBUG(dbgs() << "Instruction to promote is in a different block ("do { } while (false) | |||
| 7397 | << ToBePromoted->getParent()->getName()do { } while (false) | |||
| 7398 | << ") than the transition (" << Parent->getName()do { } while (false) | |||
| 7399 | << ").\n")do { } while (false); | |||
| 7400 | return false; | |||
| 7401 | } | |||
| 7402 | ||||
| 7403 | if (VPH.canCombine(ToBePromoted)) { | |||
| 7404 | LLVM_DEBUG(dbgs() << "Assume " << *Inst << '\n'do { } while (false) | |||
| 7405 | << "will be combined with: " << *ToBePromoted << '\n')do { } while (false); | |||
| 7406 | VPH.recordCombineInstruction(ToBePromoted); | |||
| 7407 | bool Changed = VPH.promote(); | |||
| 7408 | NumStoreExtractExposed += Changed; | |||
| 7409 | return Changed; | |||
| 7410 | } | |||
| 7411 | ||||
| 7412 | LLVM_DEBUG(dbgs() << "Try promoting.\n")do { } while (false); | |||
| 7413 | if (!VPH.canPromote(ToBePromoted) || !VPH.shouldPromote(ToBePromoted)) | |||
| 7414 | return false; | |||
| 7415 | ||||
| 7416 | LLVM_DEBUG(dbgs() << "Promoting is possible... Enqueue for promotion!\n")do { } while (false); | |||
| 7417 | ||||
| 7418 | VPH.enqueueForPromotion(ToBePromoted); | |||
| 7419 | Inst = ToBePromoted; | |||
| 7420 | } | |||
| 7421 | return false; | |||
| 7422 | } | |||
| 7423 | ||||
| 7424 | /// For the instruction sequence of store below, F and I values | |||
| 7425 | /// are bundled together as an i64 value before being stored into memory. | |||
| 7426 | /// Sometimes it is more efficient to generate separate stores for F and I, | |||
| 7427 | /// which can remove the bitwise instructions or sink them to colder places. | |||
| 7428 | /// | |||
| 7429 | /// (store (or (zext (bitcast F to i32) to i64), | |||
| 7430 | /// (shl (zext I to i64), 32)), addr) --> | |||
| 7431 | /// (store F, addr) and (store I, addr+4) | |||
| 7432 | /// | |||
| 7433 | /// Similarly, splitting for other merged store can also be beneficial, like: | |||
| 7434 | /// For pair of {i32, i32}, i64 store --> two i32 stores. | |||
| 7435 | /// For pair of {i32, i16}, i64 store --> two i32 stores. | |||
| 7436 | /// For pair of {i16, i16}, i32 store --> two i16 stores. | |||
| 7437 | /// For pair of {i16, i8}, i32 store --> two i16 stores. | |||
| 7438 | /// For pair of {i8, i8}, i16 store --> two i8 stores. | |||
| 7439 | /// | |||
| 7440 | /// We allow each target to determine specifically which kind of splitting is | |||
| 7441 | /// supported. | |||
| 7442 | /// | |||
| 7443 | /// The store patterns are commonly seen from the simple code snippet below | |||
| 7444 | /// if only std::make_pair(...) is sroa transformed before inlined into hoo. | |||
| 7445 | /// void goo(const std::pair<int, float> &); | |||
| 7446 | /// hoo() { | |||
| 7447 | /// ... | |||
| 7448 | /// goo(std::make_pair(tmp, ftmp)); | |||
| 7449 | /// ... | |||
| 7450 | /// } | |||
| 7451 | /// | |||
| 7452 | /// Although we already have similar splitting in DAG Combine, we duplicate | |||
| 7453 | /// it in CodeGenPrepare to catch the case in which pattern is across | |||
| 7454 | /// multiple BBs. The logic in DAG Combine is kept to catch case generated | |||
| 7455 | /// during code expansion. | |||
| 7456 | static bool splitMergedValStore(StoreInst &SI, const DataLayout &DL, | |||
| 7457 | const TargetLowering &TLI) { | |||
| 7458 | // Handle simple but common cases only. | |||
| 7459 | Type *StoreType = SI.getValueOperand()->getType(); | |||
| 7460 | ||||
| 7461 | // The code below assumes shifting a value by <number of bits>, | |||
| 7462 | // whereas scalable vectors would have to be shifted by | |||
| 7463 | // <2log(vscale) + number of bits> in order to store the | |||
| 7464 | // low/high parts. Bailing out for now. | |||
| 7465 | if (isa<ScalableVectorType>(StoreType)) | |||
| 7466 | return false; | |||
| 7467 | ||||
| 7468 | if (!DL.typeSizeEqualsStoreSize(StoreType) || | |||
| 7469 | DL.getTypeSizeInBits(StoreType) == 0) | |||
| 7470 | return false; | |||
| 7471 | ||||
| 7472 | unsigned HalfValBitSize = DL.getTypeSizeInBits(StoreType) / 2; | |||
| 7473 | Type *SplitStoreType = Type::getIntNTy(SI.getContext(), HalfValBitSize); | |||
| 7474 | if (!DL.typeSizeEqualsStoreSize(SplitStoreType)) | |||
| 7475 | return false; | |||
| 7476 | ||||
| 7477 | // Don't split the store if it is volatile. | |||
| 7478 | if (SI.isVolatile()) | |||
| 7479 | return false; | |||
| 7480 | ||||
| 7481 | // Match the following patterns: | |||
| 7482 | // (store (or (zext LValue to i64), | |||
| 7483 | // (shl (zext HValue to i64), 32)), HalfValBitSize) | |||
| 7484 | // or | |||
| 7485 | // (store (or (shl (zext HValue to i64), 32)), HalfValBitSize) | |||
| 7486 | // (zext LValue to i64), | |||
| 7487 | // Expect both operands of OR and the first operand of SHL have only | |||
| 7488 | // one use. | |||
| 7489 | Value *LValue, *HValue; | |||
| 7490 | if (!match(SI.getValueOperand(), | |||
| 7491 | m_c_Or(m_OneUse(m_ZExt(m_Value(LValue))), | |||
| 7492 | m_OneUse(m_Shl(m_OneUse(m_ZExt(m_Value(HValue))), | |||
| 7493 | m_SpecificInt(HalfValBitSize)))))) | |||
| 7494 | return false; | |||
| 7495 | ||||
| 7496 | // Check LValue and HValue are int with size less or equal than 32. | |||
| 7497 | if (!LValue->getType()->isIntegerTy() || | |||
| 7498 | DL.getTypeSizeInBits(LValue->getType()) > HalfValBitSize || | |||
| 7499 | !HValue->getType()->isIntegerTy() || | |||
| 7500 | DL.getTypeSizeInBits(HValue->getType()) > HalfValBitSize) | |||
| 7501 | return false; | |||
| 7502 | ||||
| 7503 | // If LValue/HValue is a bitcast instruction, use the EVT before bitcast | |||
| 7504 | // as the input of target query. | |||
| 7505 | auto *LBC = dyn_cast<BitCastInst>(LValue); | |||
| 7506 | auto *HBC = dyn_cast<BitCastInst>(HValue); | |||
| 7507 | EVT LowTy = LBC ? EVT::getEVT(LBC->getOperand(0)->getType()) | |||
| 7508 | : EVT::getEVT(LValue->getType()); | |||
| 7509 | EVT HighTy = HBC ? EVT::getEVT(HBC->getOperand(0)->getType()) | |||
| 7510 | : EVT::getEVT(HValue->getType()); | |||
| 7511 | if (!ForceSplitStore && !TLI.isMultiStoresCheaperThanBitsMerge(LowTy, HighTy)) | |||
| 7512 | return false; | |||
| 7513 | ||||
| 7514 | // Start to split store. | |||
| 7515 | IRBuilder<> Builder(SI.getContext()); | |||
| 7516 | Builder.SetInsertPoint(&SI); | |||
| 7517 | ||||
| 7518 | // If LValue/HValue is a bitcast in another BB, create a new one in current | |||
| 7519 | // BB so it may be merged with the splitted stores by dag combiner. | |||
| 7520 | if (LBC && LBC->getParent() != SI.getParent()) | |||
| 7521 | LValue = Builder.CreateBitCast(LBC->getOperand(0), LBC->getType()); | |||
| 7522 | if (HBC && HBC->getParent() != SI.getParent()) | |||
| 7523 | HValue = Builder.CreateBitCast(HBC->getOperand(0), HBC->getType()); | |||
| 7524 | ||||
| 7525 | bool IsLE = SI.getModule()->getDataLayout().isLittleEndian(); | |||
| 7526 | auto CreateSplitStore = [&](Value *V, bool Upper) { | |||
| 7527 | V = Builder.CreateZExtOrBitCast(V, SplitStoreType); | |||
| 7528 | Value *Addr = Builder.CreateBitCast( | |||
| 7529 | SI.getOperand(1), | |||
| 7530 | SplitStoreType->getPointerTo(SI.getPointerAddressSpace())); | |||
| 7531 | Align Alignment = SI.getAlign(); | |||
| 7532 | const bool IsOffsetStore = (IsLE && Upper) || (!IsLE && !Upper); | |||
| 7533 | if (IsOffsetStore) { | |||
| 7534 | Addr = Builder.CreateGEP( | |||
| 7535 | SplitStoreType, Addr, | |||
| 7536 | ConstantInt::get(Type::getInt32Ty(SI.getContext()), 1)); | |||
| 7537 | ||||
| 7538 | // When splitting the store in half, naturally one half will retain the | |||
| 7539 | // alignment of the original wider store, regardless of whether it was | |||
| 7540 | // over-aligned or not, while the other will require adjustment. | |||
| 7541 | Alignment = commonAlignment(Alignment, HalfValBitSize / 8); | |||
| 7542 | } | |||
| 7543 | Builder.CreateAlignedStore(V, Addr, Alignment); | |||
| 7544 | }; | |||
| 7545 | ||||
| 7546 | CreateSplitStore(LValue, false); | |||
| 7547 | CreateSplitStore(HValue, true); | |||
| 7548 | ||||
| 7549 | // Delete the old store. | |||
| 7550 | SI.eraseFromParent(); | |||
| 7551 | return true; | |||
| 7552 | } | |||
| 7553 | ||||
| 7554 | // Return true if the GEP has two operands, the first operand is of a sequential | |||
| 7555 | // type, and the second operand is a constant. | |||
| 7556 | static bool GEPSequentialConstIndexed(GetElementPtrInst *GEP) { | |||
| 7557 | gep_type_iterator I = gep_type_begin(*GEP); | |||
| 7558 | return GEP->getNumOperands() == 2 && | |||
| 7559 | I.isSequential() && | |||
| 7560 | isa<ConstantInt>(GEP->getOperand(1)); | |||
| 7561 | } | |||
| 7562 | ||||
| 7563 | // Try unmerging GEPs to reduce liveness interference (register pressure) across | |||
| 7564 | // IndirectBr edges. Since IndirectBr edges tend to touch on many blocks, | |||
| 7565 | // reducing liveness interference across those edges benefits global register | |||
| 7566 | // allocation. Currently handles only certain cases. | |||
| 7567 | // | |||
| 7568 | // For example, unmerge %GEPI and %UGEPI as below. | |||
| 7569 | // | |||
| 7570 | // ---------- BEFORE ---------- | |||
| 7571 | // SrcBlock: | |||
| 7572 | // ... | |||
| 7573 | // %GEPIOp = ... | |||
| 7574 | // ... | |||
| 7575 | // %GEPI = gep %GEPIOp, Idx | |||
| 7576 | // ... | |||
| 7577 | // indirectbr ... [ label %DstB0, label %DstB1, ... label %DstBi ... ] | |||
| 7578 | // (* %GEPI is alive on the indirectbr edges due to other uses ahead) | |||
| 7579 | // (* %GEPIOp is alive on the indirectbr edges only because of it's used by | |||
| 7580 | // %UGEPI) | |||
| 7581 | // | |||
| 7582 | // DstB0: ... (there may be a gep similar to %UGEPI to be unmerged) | |||
| 7583 | // DstB1: ... (there may be a gep similar to %UGEPI to be unmerged) | |||
| 7584 | // ... | |||
| 7585 | // | |||
| 7586 | // DstBi: | |||
| 7587 | // ... | |||
| 7588 | // %UGEPI = gep %GEPIOp, UIdx | |||
| 7589 | // ... | |||
| 7590 | // --------------------------- | |||
| 7591 | // | |||
| 7592 | // ---------- AFTER ---------- | |||
| 7593 | // SrcBlock: | |||
| 7594 | // ... (same as above) | |||
| 7595 | // (* %GEPI is still alive on the indirectbr edges) | |||
| 7596 | // (* %GEPIOp is no longer alive on the indirectbr edges as a result of the | |||
| 7597 | // unmerging) | |||
| 7598 | // ... | |||
| 7599 | // | |||
| 7600 | // DstBi: | |||
| 7601 | // ... | |||
| 7602 | // %UGEPI = gep %GEPI, (UIdx-Idx) | |||
| 7603 | // ... | |||
| 7604 | // --------------------------- | |||
| 7605 | // | |||
| 7606 | // The register pressure on the IndirectBr edges is reduced because %GEPIOp is | |||
| 7607 | // no longer alive on them. | |||
| 7608 | // | |||
| 7609 | // We try to unmerge GEPs here in CodGenPrepare, as opposed to limiting merging | |||
| 7610 | // of GEPs in the first place in InstCombiner::visitGetElementPtrInst() so as | |||
| 7611 | // not to disable further simplications and optimizations as a result of GEP | |||
| 7612 | // merging. | |||
| 7613 | // | |||
| 7614 | // Note this unmerging may increase the length of the data flow critical path | |||
| 7615 | // (the path from %GEPIOp to %UGEPI would go through %GEPI), which is a tradeoff | |||
| 7616 | // between the register pressure and the length of data-flow critical | |||
| 7617 | // path. Restricting this to the uncommon IndirectBr case would minimize the | |||
| 7618 | // impact of potentially longer critical path, if any, and the impact on compile | |||
| 7619 | // time. | |||
| 7620 | static bool tryUnmergingGEPsAcrossIndirectBr(GetElementPtrInst *GEPI, | |||
| 7621 | const TargetTransformInfo *TTI) { | |||
| 7622 | BasicBlock *SrcBlock = GEPI->getParent(); | |||
| 7623 | // Check that SrcBlock ends with an IndirectBr. If not, give up. The common | |||
| 7624 | // (non-IndirectBr) cases exit early here. | |||
| 7625 | if (!isa<IndirectBrInst>(SrcBlock->getTerminator())) | |||
| 7626 | return false; | |||
| 7627 | // Check that GEPI is a simple gep with a single constant index. | |||
| 7628 | if (!GEPSequentialConstIndexed(GEPI)) | |||
| 7629 | return false; | |||
| 7630 | ConstantInt *GEPIIdx = cast<ConstantInt>(GEPI->getOperand(1)); | |||
| 7631 | // Check that GEPI is a cheap one. | |||
| 7632 | if (TTI->getIntImmCost(GEPIIdx->getValue(), GEPIIdx->getType(), | |||
| 7633 | TargetTransformInfo::TCK_SizeAndLatency) | |||
| 7634 | > TargetTransformInfo::TCC_Basic) | |||
| 7635 | return false; | |||
| 7636 | Value *GEPIOp = GEPI->getOperand(0); | |||
| 7637 | // Check that GEPIOp is an instruction that's also defined in SrcBlock. | |||
| 7638 | if (!isa<Instruction>(GEPIOp)) | |||
| 7639 | return false; | |||
| 7640 | auto *GEPIOpI = cast<Instruction>(GEPIOp); | |||
| 7641 | if (GEPIOpI->getParent() != SrcBlock) | |||
| 7642 | return false; | |||
| 7643 | // Check that GEP is used outside the block, meaning it's alive on the | |||
| 7644 | // IndirectBr edge(s). | |||
| 7645 | if (find_if(GEPI->users(), [&](User *Usr) { | |||
| 7646 | if (auto *I = dyn_cast<Instruction>(Usr)) { | |||
| 7647 | if (I->getParent() != SrcBlock) { | |||
| 7648 | return true; | |||
| 7649 | } | |||
| 7650 | } | |||
| 7651 | return false; | |||
| 7652 | }) == GEPI->users().end()) | |||
| 7653 | return false; | |||
| 7654 | // The second elements of the GEP chains to be unmerged. | |||
| 7655 | std::vector<GetElementPtrInst *> UGEPIs; | |||
| 7656 | // Check each user of GEPIOp to check if unmerging would make GEPIOp not alive | |||
| 7657 | // on IndirectBr edges. | |||
| 7658 | for (User *Usr : GEPIOp->users()) { | |||
| 7659 | if (Usr == GEPI) continue; | |||
| 7660 | // Check if Usr is an Instruction. If not, give up. | |||
| 7661 | if (!isa<Instruction>(Usr)) | |||
| 7662 | return false; | |||
| 7663 | auto *UI = cast<Instruction>(Usr); | |||
| 7664 | // Check if Usr in the same block as GEPIOp, which is fine, skip. | |||
| 7665 | if (UI->getParent() == SrcBlock) | |||
| 7666 | continue; | |||
| 7667 | // Check if Usr is a GEP. If not, give up. | |||
| 7668 | if (!isa<GetElementPtrInst>(Usr)) | |||
| 7669 | return false; | |||
| 7670 | auto *UGEPI = cast<GetElementPtrInst>(Usr); | |||
| 7671 | // Check if UGEPI is a simple gep with a single constant index and GEPIOp is | |||
| 7672 | // the pointer operand to it. If so, record it in the vector. If not, give | |||
| 7673 | // up. | |||
| 7674 | if (!GEPSequentialConstIndexed(UGEPI)) | |||
| 7675 | return false; | |||
| 7676 | if (UGEPI->getOperand(0) != GEPIOp) | |||
| 7677 | return false; | |||
| 7678 | if (GEPIIdx->getType() != | |||
| 7679 | cast<ConstantInt>(UGEPI->getOperand(1))->getType()) | |||
| 7680 | return false; | |||
| 7681 | ConstantInt *UGEPIIdx = cast<ConstantInt>(UGEPI->getOperand(1)); | |||
| 7682 | if (TTI->getIntImmCost(UGEPIIdx->getValue(), UGEPIIdx->getType(), | |||
| 7683 | TargetTransformInfo::TCK_SizeAndLatency) | |||
| 7684 | > TargetTransformInfo::TCC_Basic) | |||
| 7685 | return false; | |||
| 7686 | UGEPIs.push_back(UGEPI); | |||
| 7687 | } | |||
| 7688 | if (UGEPIs.size() == 0) | |||
| 7689 | return false; | |||
| 7690 | // Check the materializing cost of (Uidx-Idx). | |||
| 7691 | for (GetElementPtrInst *UGEPI : UGEPIs) { | |||
| 7692 | ConstantInt *UGEPIIdx = cast<ConstantInt>(UGEPI->getOperand(1)); | |||
| 7693 | APInt NewIdx = UGEPIIdx->getValue() - GEPIIdx->getValue(); | |||
| 7694 | InstructionCost ImmCost = TTI->getIntImmCost( | |||
| 7695 | NewIdx, GEPIIdx->getType(), TargetTransformInfo::TCK_SizeAndLatency); | |||
| 7696 | if (ImmCost > TargetTransformInfo::TCC_Basic) | |||
| 7697 | return false; | |||
| 7698 | } | |||
| 7699 | // Now unmerge between GEPI and UGEPIs. | |||
| 7700 | for (GetElementPtrInst *UGEPI : UGEPIs) { | |||
| 7701 | UGEPI->setOperand(0, GEPI); | |||
| 7702 | ConstantInt *UGEPIIdx = cast<ConstantInt>(UGEPI->getOperand(1)); | |||
| 7703 | Constant *NewUGEPIIdx = | |||
| 7704 | ConstantInt::get(GEPIIdx->getType(), | |||
| 7705 | UGEPIIdx->getValue() - GEPIIdx->getValue()); | |||
| 7706 | UGEPI->setOperand(1, NewUGEPIIdx); | |||
| 7707 | // If GEPI is not inbounds but UGEPI is inbounds, change UGEPI to not | |||
| 7708 | // inbounds to avoid UB. | |||
| 7709 | if (!GEPI->isInBounds()) { | |||
| 7710 | UGEPI->setIsInBounds(false); | |||
| 7711 | } | |||
| 7712 | } | |||
| 7713 | // After unmerging, verify that GEPIOp is actually only used in SrcBlock (not | |||
| 7714 | // alive on IndirectBr edges). | |||
| 7715 | assert(find_if(GEPIOp->users(), [&](User *Usr) {((void)0) | |||
| 7716 | return cast<Instruction>(Usr)->getParent() != SrcBlock;((void)0) | |||
| 7717 | }) == GEPIOp->users().end() && "GEPIOp is used outside SrcBlock")((void)0); | |||
| 7718 | return true; | |||
| 7719 | } | |||
| 7720 | ||||
| 7721 | static bool optimizeBranch(BranchInst *Branch, const TargetLowering &TLI) { | |||
| 7722 | // Try and convert | |||
| 7723 | // %c = icmp ult %x, 8 | |||
| 7724 | // br %c, bla, blb | |||
| 7725 | // %tc = lshr %x, 3 | |||
| 7726 | // to | |||
| 7727 | // %tc = lshr %x, 3 | |||
| 7728 | // %c = icmp eq %tc, 0 | |||
| 7729 | // br %c, bla, blb | |||
| 7730 | // Creating the cmp to zero can be better for the backend, especially if the | |||
| 7731 | // lshr produces flags that can be used automatically. | |||
| 7732 | if (!TLI.preferZeroCompareBranch() || !Branch->isConditional()) | |||
| 7733 | return false; | |||
| 7734 | ||||
| 7735 | ICmpInst *Cmp = dyn_cast<ICmpInst>(Branch->getCondition()); | |||
| 7736 | if (!Cmp || !isa<ConstantInt>(Cmp->getOperand(1)) || !Cmp->hasOneUse()) | |||
| 7737 | return false; | |||
| 7738 | ||||
| 7739 | Value *X = Cmp->getOperand(0); | |||
| 7740 | APInt CmpC = cast<ConstantInt>(Cmp->getOperand(1))->getValue(); | |||
| 7741 | ||||
| 7742 | for (auto *U : X->users()) { | |||
| 7743 | Instruction *UI = dyn_cast<Instruction>(U); | |||
| 7744 | // A quick dominance check | |||
| 7745 | if (!UI || | |||
| 7746 | (UI->getParent() != Branch->getParent() && | |||
| 7747 | UI->getParent() != Branch->getSuccessor(0) && | |||
| 7748 | UI->getParent() != Branch->getSuccessor(1)) || | |||
| 7749 | (UI->getParent() != Branch->getParent() && | |||
| 7750 | !UI->getParent()->getSinglePredecessor())) | |||
| 7751 | continue; | |||
| 7752 | ||||
| 7753 | if (CmpC.isPowerOf2() && Cmp->getPredicate() == ICmpInst::ICMP_ULT && | |||
| 7754 | match(UI, m_Shr(m_Specific(X), m_SpecificInt(CmpC.logBase2())))) { | |||
| 7755 | IRBuilder<> Builder(Branch); | |||
| 7756 | if (UI->getParent() != Branch->getParent()) | |||
| 7757 | UI->moveBefore(Branch); | |||
| 7758 | Value *NewCmp = Builder.CreateCmp(ICmpInst::ICMP_EQ, UI, | |||
| 7759 | ConstantInt::get(UI->getType(), 0)); | |||
| 7760 | LLVM_DEBUG(dbgs() << "Converting " << *Cmp << "\n")do { } while (false); | |||
| 7761 | LLVM_DEBUG(dbgs() << " to compare on zero: " << *NewCmp << "\n")do { } while (false); | |||
| 7762 | Cmp->replaceAllUsesWith(NewCmp); | |||
| 7763 | return true; | |||
| 7764 | } | |||
| 7765 | if (Cmp->isEquality() && | |||
| 7766 | (match(UI, m_Add(m_Specific(X), m_SpecificInt(-CmpC))) || | |||
| 7767 | match(UI, m_Sub(m_Specific(X), m_SpecificInt(CmpC))))) { | |||
| 7768 | IRBuilder<> Builder(Branch); | |||
| 7769 | if (UI->getParent() != Branch->getParent()) | |||
| 7770 | UI->moveBefore(Branch); | |||
| 7771 | Value *NewCmp = Builder.CreateCmp(Cmp->getPredicate(), UI, | |||
| 7772 | ConstantInt::get(UI->getType(), 0)); | |||
| 7773 | LLVM_DEBUG(dbgs() << "Converting " << *Cmp << "\n")do { } while (false); | |||
| 7774 | LLVM_DEBUG(dbgs() << " to compare on zero: " << *NewCmp << "\n")do { } while (false); | |||
| 7775 | Cmp->replaceAllUsesWith(NewCmp); | |||
| 7776 | return true; | |||
| 7777 | } | |||
| 7778 | } | |||
| 7779 | return false; | |||
| 7780 | } | |||
| 7781 | ||||
| 7782 | bool CodeGenPrepare::optimizeInst(Instruction *I, bool &ModifiedDT) { | |||
| 7783 | // Bail out if we inserted the instruction to prevent optimizations from | |||
| 7784 | // stepping on each other's toes. | |||
| 7785 | if (InsertedInsts.count(I)) | |||
| 7786 | return false; | |||
| 7787 | ||||
| 7788 | // TODO: Move into the switch on opcode below here. | |||
| 7789 | if (PHINode *P = dyn_cast<PHINode>(I)) { | |||
| 7790 | // It is possible for very late stage optimizations (such as SimplifyCFG) | |||
| 7791 | // to introduce PHI nodes too late to be cleaned up. If we detect such a | |||
| 7792 | // trivial PHI, go ahead and zap it here. | |||
| 7793 | if (Value *V = SimplifyInstruction(P, {*DL, TLInfo})) { | |||
| 7794 | LargeOffsetGEPMap.erase(P); | |||
| 7795 | P->replaceAllUsesWith(V); | |||
| 7796 | P->eraseFromParent(); | |||
| 7797 | ++NumPHIsElim; | |||
| 7798 | return true; | |||
| 7799 | } | |||
| 7800 | return false; | |||
| 7801 | } | |||
| 7802 | ||||
| 7803 | if (CastInst *CI = dyn_cast<CastInst>(I)) { | |||
| 7804 | // If the source of the cast is a constant, then this should have | |||
| 7805 | // already been constant folded. The only reason NOT to constant fold | |||
| 7806 | // it is if something (e.g. LSR) was careful to place the constant | |||
| 7807 | // evaluation in a block other than then one that uses it (e.g. to hoist | |||
| 7808 | // the address of globals out of a loop). If this is the case, we don't | |||
| 7809 | // want to forward-subst the cast. | |||
| 7810 | if (isa<Constant>(CI->getOperand(0))) | |||
| 7811 | return false; | |||
| 7812 | ||||
| 7813 | if (OptimizeNoopCopyExpression(CI, *TLI, *DL)) | |||
| 7814 | return true; | |||
| 7815 | ||||
| 7816 | if (isa<ZExtInst>(I) || isa<SExtInst>(I)) { | |||
| 7817 | /// Sink a zext or sext into its user blocks if the target type doesn't | |||
| 7818 | /// fit in one register | |||
| 7819 | if (TLI->getTypeAction(CI->getContext(), | |||
| 7820 | TLI->getValueType(*DL, CI->getType())) == | |||
| 7821 | TargetLowering::TypeExpandInteger) { | |||
| 7822 | return SinkCast(CI); | |||
| 7823 | } else { | |||
| 7824 | bool MadeChange = optimizeExt(I); | |||
| 7825 | return MadeChange | optimizeExtUses(I); | |||
| 7826 | } | |||
| 7827 | } | |||
| 7828 | return false; | |||
| 7829 | } | |||
| 7830 | ||||
| 7831 | if (auto *Cmp = dyn_cast<CmpInst>(I)) | |||
| 7832 | if (optimizeCmp(Cmp, ModifiedDT)) | |||
| 7833 | return true; | |||
| 7834 | ||||
| 7835 | if (LoadInst *LI = dyn_cast<LoadInst>(I)) { | |||
| 7836 | LI->setMetadata(LLVMContext::MD_invariant_group, nullptr); | |||
| 7837 | bool Modified = optimizeLoadExt(LI); | |||
| 7838 | unsigned AS = LI->getPointerAddressSpace(); | |||
| 7839 | Modified |= optimizeMemoryInst(I, I->getOperand(0), LI->getType(), AS); | |||
| 7840 | return Modified; | |||
| 7841 | } | |||
| 7842 | ||||
| 7843 | if (StoreInst *SI = dyn_cast<StoreInst>(I)) { | |||
| 7844 | if (splitMergedValStore(*SI, *DL, *TLI)) | |||
| 7845 | return true; | |||
| 7846 | SI->setMetadata(LLVMContext::MD_invariant_group, nullptr); | |||
| 7847 | unsigned AS = SI->getPointerAddressSpace(); | |||
| 7848 | return optimizeMemoryInst(I, SI->getOperand(1), | |||
| 7849 | SI->getOperand(0)->getType(), AS); | |||
| 7850 | } | |||
| 7851 | ||||
| 7852 | if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) { | |||
| 7853 | unsigned AS = RMW->getPointerAddressSpace(); | |||
| 7854 | return optimizeMemoryInst(I, RMW->getPointerOperand(), | |||
| 7855 | RMW->getType(), AS); | |||
| 7856 | } | |||
| 7857 | ||||
| 7858 | if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(I)) { | |||
| 7859 | unsigned AS = CmpX->getPointerAddressSpace(); | |||
| 7860 | return optimizeMemoryInst(I, CmpX->getPointerOperand(), | |||
| 7861 | CmpX->getCompareOperand()->getType(), AS); | |||
| 7862 | } | |||
| 7863 | ||||
| 7864 | BinaryOperator *BinOp = dyn_cast<BinaryOperator>(I); | |||
| 7865 | ||||
| 7866 | if (BinOp && (BinOp->getOpcode() == Instruction::And) && EnableAndCmpSinking) | |||
| 7867 | return sinkAndCmp0Expression(BinOp, *TLI, InsertedInsts); | |||
| 7868 | ||||
| 7869 | // TODO: Move this into the switch on opcode - it handles shifts already. | |||
| 7870 | if (BinOp && (BinOp->getOpcode() == Instruction::AShr || | |||
| 7871 | BinOp->getOpcode() == Instruction::LShr)) { | |||
| 7872 | ConstantInt *CI = dyn_cast<ConstantInt>(BinOp->getOperand(1)); | |||
| 7873 | if (CI && TLI->hasExtractBitsInsn()) | |||
| 7874 | if (OptimizeExtractBits(BinOp, CI, *TLI, *DL)) | |||
| 7875 | return true; | |||
| 7876 | } | |||
| 7877 | ||||
| 7878 | if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) { | |||
| 7879 | if (GEPI->hasAllZeroIndices()) { | |||
| 7880 | /// The GEP operand must be a pointer, so must its result -> BitCast | |||
| 7881 | Instruction *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(), | |||
| 7882 | GEPI->getName(), GEPI); | |||
| 7883 | NC->setDebugLoc(GEPI->getDebugLoc()); | |||
| 7884 | GEPI->replaceAllUsesWith(NC); | |||
| 7885 | GEPI->eraseFromParent(); | |||
| 7886 | ++NumGEPsElim; | |||
| 7887 | optimizeInst(NC, ModifiedDT); | |||
| 7888 | return true; | |||
| 7889 | } | |||
| 7890 | if (tryUnmergingGEPsAcrossIndirectBr(GEPI, TTI)) { | |||
| 7891 | return true; | |||
| 7892 | } | |||
| 7893 | return false; | |||
| 7894 | } | |||
| 7895 | ||||
| 7896 | if (FreezeInst *FI = dyn_cast<FreezeInst>(I)) { | |||
| 7897 | // freeze(icmp a, const)) -> icmp (freeze a), const | |||
| 7898 | // This helps generate efficient conditional jumps. | |||
| 7899 | Instruction *CmpI = nullptr; | |||
| 7900 | if (ICmpInst *II = dyn_cast<ICmpInst>(FI->getOperand(0))) | |||
| 7901 | CmpI = II; | |||
| 7902 | else if (FCmpInst *F = dyn_cast<FCmpInst>(FI->getOperand(0))) | |||
| 7903 | CmpI = F->getFastMathFlags().none() ? F : nullptr; | |||
| 7904 | ||||
| 7905 | if (CmpI && CmpI->hasOneUse()) { | |||
| 7906 | auto Op0 = CmpI->getOperand(0), Op1 = CmpI->getOperand(1); | |||
| 7907 | bool Const0 = isa<ConstantInt>(Op0) || isa<ConstantFP>(Op0) || | |||
| 7908 | isa<ConstantPointerNull>(Op0); | |||
| 7909 | bool Const1 = isa<ConstantInt>(Op1) || isa<ConstantFP>(Op1) || | |||
| 7910 | isa<ConstantPointerNull>(Op1); | |||
| 7911 | if (Const0 || Const1) { | |||
| 7912 | if (!Const0 || !Const1) { | |||
| 7913 | auto *F = new FreezeInst(Const0 ? Op1 : Op0, "", CmpI); | |||
| 7914 | F->takeName(FI); | |||
| 7915 | CmpI->setOperand(Const0 ? 1 : 0, F); | |||
| 7916 | } | |||
| 7917 | FI->replaceAllUsesWith(CmpI); | |||
| 7918 | FI->eraseFromParent(); | |||
| 7919 | return true; | |||
| 7920 | } | |||
| 7921 | } | |||
| 7922 | return false; | |||
| 7923 | } | |||
| 7924 | ||||
| 7925 | if (tryToSinkFreeOperands(I)) | |||
| 7926 | return true; | |||
| 7927 | ||||
| 7928 | switch (I->getOpcode()) { | |||
| 7929 | case Instruction::Shl: | |||
| 7930 | case Instruction::LShr: | |||
| 7931 | case Instruction::AShr: | |||
| 7932 | return optimizeShiftInst(cast<BinaryOperator>(I)); | |||
| 7933 | case Instruction::Call: | |||
| 7934 | return optimizeCallInst(cast<CallInst>(I), ModifiedDT); | |||
| 7935 | case Instruction::Select: | |||
| 7936 | return optimizeSelectInst(cast<SelectInst>(I)); | |||
| 7937 | case Instruction::ShuffleVector: | |||
| 7938 | return optimizeShuffleVectorInst(cast<ShuffleVectorInst>(I)); | |||
| 7939 | case Instruction::Switch: | |||
| 7940 | return optimizeSwitchInst(cast<SwitchInst>(I)); | |||
| 7941 | case Instruction::ExtractElement: | |||
| 7942 | return optimizeExtractElementInst(cast<ExtractElementInst>(I)); | |||
| 7943 | case Instruction::Br: | |||
| 7944 | return optimizeBranch(cast<BranchInst>(I), *TLI); | |||
| 7945 | } | |||
| 7946 | ||||
| 7947 | return false; | |||
| 7948 | } | |||
| 7949 | ||||
| 7950 | /// Given an OR instruction, check to see if this is a bitreverse | |||
| 7951 | /// idiom. If so, insert the new intrinsic and return true. | |||
| 7952 | bool CodeGenPrepare::makeBitReverse(Instruction &I) { | |||
| 7953 | if (!I.getType()->isIntegerTy() || | |||
| 7954 | !TLI->isOperationLegalOrCustom(ISD::BITREVERSE, | |||
| 7955 | TLI->getValueType(*DL, I.getType(), true))) | |||
| 7956 | return false; | |||
| 7957 | ||||
| 7958 | SmallVector<Instruction*, 4> Insts; | |||
| 7959 | if (!recognizeBSwapOrBitReverseIdiom(&I, false, true, Insts)) | |||
| 7960 | return false; | |||
| 7961 | Instruction *LastInst = Insts.back(); | |||
| 7962 | I.replaceAllUsesWith(LastInst); | |||
| 7963 | RecursivelyDeleteTriviallyDeadInstructions( | |||
| 7964 | &I, TLInfo, nullptr, [&](Value *V) { removeAllAssertingVHReferences(V); }); | |||
| 7965 | return true; | |||
| 7966 | } | |||
| 7967 | ||||
| 7968 | // In this pass we look for GEP and cast instructions that are used | |||
| 7969 | // across basic blocks and rewrite them to improve basic-block-at-a-time | |||
| 7970 | // selection. | |||
| 7971 | bool CodeGenPrepare::optimizeBlock(BasicBlock &BB, bool &ModifiedDT) { | |||
| 7972 | SunkAddrs.clear(); | |||
| 7973 | bool MadeChange = false; | |||
| 7974 | ||||
| 7975 | CurInstIterator = BB.begin(); | |||
| 7976 | while (CurInstIterator != BB.end()) { | |||
| 7977 | MadeChange |= optimizeInst(&*CurInstIterator++, ModifiedDT); | |||
| 7978 | if (ModifiedDT) | |||
| 7979 | return true; | |||
| 7980 | } | |||
| 7981 | ||||
| 7982 | bool MadeBitReverse = true; | |||
| 7983 | while (MadeBitReverse) { | |||
| 7984 | MadeBitReverse = false; | |||
| 7985 | for (auto &I : reverse(BB)) { | |||
| 7986 | if (makeBitReverse(I)) { | |||
| 7987 | MadeBitReverse = MadeChange = true; | |||
| 7988 | break; | |||
| 7989 | } | |||
| 7990 | } | |||
| 7991 | } | |||
| 7992 | MadeChange |= dupRetToEnableTailCallOpts(&BB, ModifiedDT); | |||
| 7993 | ||||
| 7994 | return MadeChange; | |||
| 7995 | } | |||
| 7996 | ||||
| 7997 | // Some CGP optimizations may move or alter what's computed in a block. Check | |||
| 7998 | // whether a dbg.value intrinsic could be pointed at a more appropriate operand. | |||
| 7999 | bool CodeGenPrepare::fixupDbgValue(Instruction *I) { | |||
| 8000 | assert(isa<DbgValueInst>(I))((void)0); | |||
| 8001 | DbgValueInst &DVI = *cast<DbgValueInst>(I); | |||
| 8002 | ||||
| 8003 | // Does this dbg.value refer to a sunk address calculation? | |||
| 8004 | bool AnyChange = false; | |||
| 8005 | SmallDenseSet<Value *> LocationOps(DVI.location_ops().begin(), | |||
| 8006 | DVI.location_ops().end()); | |||
| 8007 | for (Value *Location : LocationOps) { | |||
| 8008 | WeakTrackingVH SunkAddrVH = SunkAddrs[Location]; | |||
| 8009 | Value *SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr; | |||
| 8010 | if (SunkAddr) { | |||
| 8011 | // Point dbg.value at locally computed address, which should give the best | |||
| 8012 | // opportunity to be accurately lowered. This update may change the type | |||
| 8013 | // of pointer being referred to; however this makes no difference to | |||
| 8014 | // debugging information, and we can't generate bitcasts that may affect | |||
| 8015 | // codegen. | |||
| 8016 | DVI.replaceVariableLocationOp(Location, SunkAddr); | |||
| 8017 | AnyChange = true; | |||
| 8018 | } | |||
| 8019 | } | |||
| 8020 | return AnyChange; | |||
| 8021 | } | |||
| 8022 | ||||
| 8023 | // A llvm.dbg.value may be using a value before its definition, due to | |||
| 8024 | // optimizations in this pass and others. Scan for such dbg.values, and rescue | |||
| 8025 | // them by moving the dbg.value to immediately after the value definition. | |||
| 8026 | // FIXME: Ideally this should never be necessary, and this has the potential | |||
| 8027 | // to re-order dbg.value intrinsics. | |||
| 8028 | bool CodeGenPrepare::placeDbgValues(Function &F) { | |||
| 8029 | bool MadeChange = false; | |||
| 8030 | DominatorTree DT(F); | |||
| 8031 | ||||
| 8032 | for (BasicBlock &BB : F) { | |||
| 8033 | for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); BI != BE;) { | |||
| 8034 | Instruction *Insn = &*BI++; | |||
| 8035 | DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn); | |||
| 8036 | if (!DVI) | |||
| 8037 | continue; | |||
| 8038 | ||||
| 8039 | SmallVector<Instruction *, 4> VIs; | |||
| 8040 | for (Value *V : DVI->getValues()) | |||
| 8041 | if (Instruction *VI = dyn_cast_or_null<Instruction>(V)) | |||
| 8042 | VIs.push_back(VI); | |||
| 8043 | ||||
| 8044 | // This DVI may depend on multiple instructions, complicating any | |||
| 8045 | // potential sink. This block takes the defensive approach, opting to | |||
| 8046 | // "undef" the DVI if it has more than one instruction and any of them do | |||
| 8047 | // not dominate DVI. | |||
| 8048 | for (Instruction *VI : VIs) { | |||
| 8049 | if (VI->isTerminator()) | |||
| 8050 | continue; | |||
| 8051 | ||||
| 8052 | // If VI is a phi in a block with an EHPad terminator, we can't insert | |||
| 8053 | // after it. | |||
| 8054 | if (isa<PHINode>(VI) && VI->getParent()->getTerminator()->isEHPad()) | |||
| 8055 | continue; | |||
| 8056 | ||||
| 8057 | // If the defining instruction dominates the dbg.value, we do not need | |||
| 8058 | // to move the dbg.value. | |||
| 8059 | if (DT.dominates(VI, DVI)) | |||
| 8060 | continue; | |||
| 8061 | ||||
| 8062 | // If we depend on multiple instructions and any of them doesn't | |||
| 8063 | // dominate this DVI, we probably can't salvage it: moving it to | |||
| 8064 | // after any of the instructions could cause us to lose the others. | |||
| 8065 | if (VIs.size() > 1) { | |||
| 8066 | LLVM_DEBUG(do { } while (false) | |||
| 8067 | dbgs()do { } while (false) | |||
| 8068 | << "Unable to find valid location for Debug Value, undefing:\n"do { } while (false) | |||
| 8069 | << *DVI)do { } while (false); | |||
| 8070 | DVI->setUndef(); | |||
| 8071 | break; | |||
| 8072 | } | |||
| 8073 | ||||
| 8074 | LLVM_DEBUG(dbgs() << "Moving Debug Value before :\n"do { } while (false) | |||
| 8075 | << *DVI << ' ' << *VI)do { } while (false); | |||
| 8076 | DVI->removeFromParent(); | |||
| 8077 | if (isa<PHINode>(VI)) | |||
| 8078 | DVI->insertBefore(&*VI->getParent()->getFirstInsertionPt()); | |||
| 8079 | else | |||
| 8080 | DVI->insertAfter(VI); | |||
| 8081 | MadeChange = true; | |||
| 8082 | ++NumDbgValueMoved; | |||
| 8083 | } | |||
| 8084 | } | |||
| 8085 | } | |||
| 8086 | return MadeChange; | |||
| 8087 | } | |||
| 8088 | ||||
| 8089 | // Group scattered pseudo probes in a block to favor SelectionDAG. Scattered | |||
| 8090 | // probes can be chained dependencies of other regular DAG nodes and block DAG | |||
| 8091 | // combine optimizations. | |||
| 8092 | bool CodeGenPrepare::placePseudoProbes(Function &F) { | |||
| 8093 | bool MadeChange = false; | |||
| 8094 | for (auto &Block : F) { | |||
| 8095 | // Move the rest probes to the beginning of the block. | |||
| 8096 | auto FirstInst = Block.getFirstInsertionPt(); | |||
| 8097 | while (FirstInst != Block.end() && FirstInst->isDebugOrPseudoInst()) | |||
| 8098 | ++FirstInst; | |||
| 8099 | BasicBlock::iterator I(FirstInst); | |||
| 8100 | I++; | |||
| 8101 | while (I != Block.end()) { | |||
| 8102 | if (auto *II = dyn_cast<PseudoProbeInst>(I++)) { | |||
| 8103 | II->moveBefore(&*FirstInst); | |||
| 8104 | MadeChange = true; | |||
| 8105 | } | |||
| 8106 | } | |||
| 8107 | } | |||
| 8108 | return MadeChange; | |||
| 8109 | } | |||
| 8110 | ||||
| 8111 | /// Scale down both weights to fit into uint32_t. | |||
| 8112 | static void scaleWeights(uint64_t &NewTrue, uint64_t &NewFalse) { | |||
| 8113 | uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse; | |||
| 8114 | uint32_t Scale = (NewMax / std::numeric_limits<uint32_t>::max()) + 1; | |||
| 8115 | NewTrue = NewTrue / Scale; | |||
| 8116 | NewFalse = NewFalse / Scale; | |||
| 8117 | } | |||
| 8118 | ||||
| 8119 | /// Some targets prefer to split a conditional branch like: | |||
| 8120 | /// \code | |||
| 8121 | /// %0 = icmp ne i32 %a, 0 | |||
| 8122 | /// %1 = icmp ne i32 %b, 0 | |||
| 8123 | /// %or.cond = or i1 %0, %1 | |||
| 8124 | /// br i1 %or.cond, label %TrueBB, label %FalseBB | |||
| 8125 | /// \endcode | |||
| 8126 | /// into multiple branch instructions like: | |||
| 8127 | /// \code | |||
| 8128 | /// bb1: | |||
| 8129 | /// %0 = icmp ne i32 %a, 0 | |||
| 8130 | /// br i1 %0, label %TrueBB, label %bb2 | |||
| 8131 | /// bb2: | |||
| 8132 | /// %1 = icmp ne i32 %b, 0 | |||
| 8133 | /// br i1 %1, label %TrueBB, label %FalseBB | |||
| 8134 | /// \endcode | |||
| 8135 | /// This usually allows instruction selection to do even further optimizations | |||
| 8136 | /// and combine the compare with the branch instruction. Currently this is | |||
| 8137 | /// applied for targets which have "cheap" jump instructions. | |||
| 8138 | /// | |||
| 8139 | /// FIXME: Remove the (equivalent?) implementation in SelectionDAG. | |||
| 8140 | /// | |||
| 8141 | bool CodeGenPrepare::splitBranchCondition(Function &F, bool &ModifiedDT) { | |||
| 8142 | if (!TM->Options.EnableFastISel || TLI->isJumpExpensive()) | |||
| 8143 | return false; | |||
| 8144 | ||||
| 8145 | bool MadeChange = false; | |||
| 8146 | for (auto &BB : F) { | |||
| 8147 | // Does this BB end with the following? | |||
| 8148 | // %cond1 = icmp|fcmp|binary instruction ... | |||
| 8149 | // %cond2 = icmp|fcmp|binary instruction ... | |||
| 8150 | // %cond.or = or|and i1 %cond1, cond2 | |||
| 8151 | // br i1 %cond.or label %dest1, label %dest2" | |||
| 8152 | Instruction *LogicOp; | |||
| 8153 | BasicBlock *TBB, *FBB; | |||
| 8154 | if (!match(BB.getTerminator(), | |||
| 8155 | m_Br(m_OneUse(m_Instruction(LogicOp)), TBB, FBB))) | |||
| 8156 | continue; | |||
| 8157 | ||||
| 8158 | auto *Br1 = cast<BranchInst>(BB.getTerminator()); | |||
| 8159 | if (Br1->getMetadata(LLVMContext::MD_unpredictable)) | |||
| 8160 | continue; | |||
| 8161 | ||||
| 8162 | // The merging of mostly empty BB can cause a degenerate branch. | |||
| 8163 | if (TBB == FBB) | |||
| 8164 | continue; | |||
| 8165 | ||||
| 8166 | unsigned Opc; | |||
| 8167 | Value *Cond1, *Cond2; | |||
| 8168 | if (match(LogicOp, | |||
| 8169 | m_LogicalAnd(m_OneUse(m_Value(Cond1)), m_OneUse(m_Value(Cond2))))) | |||
| 8170 | Opc = Instruction::And; | |||
| 8171 | else if (match(LogicOp, m_LogicalOr(m_OneUse(m_Value(Cond1)), | |||
| 8172 | m_OneUse(m_Value(Cond2))))) | |||
| 8173 | Opc = Instruction::Or; | |||
| 8174 | else | |||
| 8175 | continue; | |||
| 8176 | ||||
| 8177 | auto IsGoodCond = [](Value *Cond) { | |||
| 8178 | return match( | |||
| 8179 | Cond, | |||
| 8180 | m_CombineOr(m_Cmp(), m_CombineOr(m_LogicalAnd(m_Value(), m_Value()), | |||
| 8181 | m_LogicalOr(m_Value(), m_Value())))); | |||
| 8182 | }; | |||
| 8183 | if (!IsGoodCond(Cond1) || !IsGoodCond(Cond2)) | |||
| 8184 | continue; | |||
| 8185 | ||||
| 8186 | LLVM_DEBUG(dbgs() << "Before branch condition splitting\n"; BB.dump())do { } while (false); | |||
| 8187 | ||||
| 8188 | // Create a new BB. | |||
| 8189 | auto *TmpBB = | |||
| 8190 | BasicBlock::Create(BB.getContext(), BB.getName() + ".cond.split", | |||
| 8191 | BB.getParent(), BB.getNextNode()); | |||
| 8192 | ||||
| 8193 | // Update original basic block by using the first condition directly by the | |||
| 8194 | // branch instruction and removing the no longer needed and/or instruction. | |||
| 8195 | Br1->setCondition(Cond1); | |||
| 8196 | LogicOp->eraseFromParent(); | |||
| 8197 | ||||
| 8198 | // Depending on the condition we have to either replace the true or the | |||
| 8199 | // false successor of the original branch instruction. | |||
| 8200 | if (Opc == Instruction::And) | |||
| 8201 | Br1->setSuccessor(0, TmpBB); | |||
| 8202 | else | |||
| 8203 | Br1->setSuccessor(1, TmpBB); | |||
| 8204 | ||||
| 8205 | // Fill in the new basic block. | |||
| 8206 | auto *Br2 = IRBuilder<>(TmpBB).CreateCondBr(Cond2, TBB, FBB); | |||
| 8207 | if (auto *I = dyn_cast<Instruction>(Cond2)) { | |||
| 8208 | I->removeFromParent(); | |||
| 8209 | I->insertBefore(Br2); | |||
| 8210 | } | |||
| 8211 | ||||
| 8212 | // Update PHI nodes in both successors. The original BB needs to be | |||
| 8213 | // replaced in one successor's PHI nodes, because the branch comes now from | |||
| 8214 | // the newly generated BB (NewBB). In the other successor we need to add one | |||
| 8215 | // incoming edge to the PHI nodes, because both branch instructions target | |||
| 8216 | // now the same successor. Depending on the original branch condition | |||
| 8217 | // (and/or) we have to swap the successors (TrueDest, FalseDest), so that | |||
| 8218 | // we perform the correct update for the PHI nodes. | |||
| 8219 | // This doesn't change the successor order of the just created branch | |||
| 8220 | // instruction (or any other instruction). | |||
| 8221 | if (Opc == Instruction::Or) | |||
| 8222 | std::swap(TBB, FBB); | |||
| 8223 | ||||
| 8224 | // Replace the old BB with the new BB. | |||
| 8225 | TBB->replacePhiUsesWith(&BB, TmpBB); | |||
| 8226 | ||||
| 8227 | // Add another incoming edge form the new BB. | |||
| 8228 | for (PHINode &PN : FBB->phis()) { | |||
| 8229 | auto *Val = PN.getIncomingValueForBlock(&BB); | |||
| 8230 | PN.addIncoming(Val, TmpBB); | |||
| 8231 | } | |||
| 8232 | ||||
| 8233 | // Update the branch weights (from SelectionDAGBuilder:: | |||
| 8234 | // FindMergedConditions). | |||
| 8235 | if (Opc == Instruction::Or) { | |||
| 8236 | // Codegen X | Y as: | |||
| 8237 | // BB1: | |||
| 8238 | // jmp_if_X TBB | |||
| 8239 | // jmp TmpBB | |||
| 8240 | // TmpBB: | |||
| 8241 | // jmp_if_Y TBB | |||
| 8242 | // jmp FBB | |||
| 8243 | // | |||
| 8244 | ||||
| 8245 | // We have flexibility in setting Prob for BB1 and Prob for NewBB. | |||
| 8246 | // The requirement is that | |||
| 8247 | // TrueProb for BB1 + (FalseProb for BB1 * TrueProb for TmpBB) | |||
| 8248 | // = TrueProb for original BB. | |||
| 8249 | // Assuming the original weights are A and B, one choice is to set BB1's | |||
| 8250 | // weights to A and A+2B, and set TmpBB's weights to A and 2B. This choice | |||
| 8251 | // assumes that | |||
| 8252 | // TrueProb for BB1 == FalseProb for BB1 * TrueProb for TmpBB. | |||
| 8253 | // Another choice is to assume TrueProb for BB1 equals to TrueProb for | |||
| 8254 | // TmpBB, but the math is more complicated. | |||
| 8255 | uint64_t TrueWeight, FalseWeight; | |||
| 8256 | if (Br1->extractProfMetadata(TrueWeight, FalseWeight)) { | |||
| 8257 | uint64_t NewTrueWeight = TrueWeight; | |||
| 8258 | uint64_t NewFalseWeight = TrueWeight + 2 * FalseWeight; | |||
| 8259 | scaleWeights(NewTrueWeight, NewFalseWeight); | |||
| 8260 | Br1->setMetadata(LLVMContext::MD_prof, MDBuilder(Br1->getContext()) | |||
| 8261 | .createBranchWeights(TrueWeight, FalseWeight)); | |||
| 8262 | ||||
| 8263 | NewTrueWeight = TrueWeight; | |||
| 8264 | NewFalseWeight = 2 * FalseWeight; | |||
| 8265 | scaleWeights(NewTrueWeight, NewFalseWeight); | |||
| 8266 | Br2->setMetadata(LLVMContext::MD_prof, MDBuilder(Br2->getContext()) | |||
| 8267 | .createBranchWeights(TrueWeight, FalseWeight)); | |||
| 8268 | } | |||
| 8269 | } else { | |||
| 8270 | // Codegen X & Y as: | |||
| 8271 | // BB1: | |||
| 8272 | // jmp_if_X TmpBB | |||
| 8273 | // jmp FBB | |||
| 8274 | // TmpBB: | |||
| 8275 | // jmp_if_Y TBB | |||
| 8276 | // jmp FBB | |||
| 8277 | // | |||
| 8278 | // This requires creation of TmpBB after CurBB. | |||
| 8279 | ||||
| 8280 | // We have flexibility in setting Prob for BB1 and Prob for TmpBB. | |||
| 8281 | // The requirement is that | |||
| 8282 | // FalseProb for BB1 + (TrueProb for BB1 * FalseProb for TmpBB) | |||
| 8283 | // = FalseProb for original BB. | |||
| 8284 | // Assuming the original weights are A and B, one choice is to set BB1's | |||
| 8285 | // weights to 2A+B and B, and set TmpBB's weights to 2A and B. This choice | |||
| 8286 | // assumes that | |||
| 8287 | // FalseProb for BB1 == TrueProb for BB1 * FalseProb for TmpBB. | |||
| 8288 | uint64_t TrueWeight, FalseWeight; | |||
| 8289 | if (Br1->extractProfMetadata(TrueWeight, FalseWeight)) { | |||
| 8290 | uint64_t NewTrueWeight = 2 * TrueWeight + FalseWeight; | |||
| 8291 | uint64_t NewFalseWeight = FalseWeight; | |||
| 8292 | scaleWeights(NewTrueWeight, NewFalseWeight); | |||
| 8293 | Br1->setMetadata(LLVMContext::MD_prof, MDBuilder(Br1->getContext()) | |||
| 8294 | .createBranchWeights(TrueWeight, FalseWeight)); | |||
| 8295 | ||||
| 8296 | NewTrueWeight = 2 * TrueWeight; | |||
| 8297 | NewFalseWeight = FalseWeight; | |||
| 8298 | scaleWeights(NewTrueWeight, NewFalseWeight); | |||
| 8299 | Br2->setMetadata(LLVMContext::MD_prof, MDBuilder(Br2->getContext()) | |||
| 8300 | .createBranchWeights(TrueWeight, FalseWeight)); | |||
| 8301 | } | |||
| 8302 | } | |||
| 8303 | ||||
| 8304 | ModifiedDT = true; | |||
| 8305 | MadeChange = true; | |||
| 8306 | ||||
| 8307 | LLVM_DEBUG(dbgs() << "After branch condition splitting\n"; BB.dump();do { } while (false) | |||
| 8308 | TmpBB->dump())do { } while (false); | |||
| 8309 | } | |||
| 8310 | return MadeChange; | |||
| 8311 | } |