| File: | src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/ScheduleDAG.cpp |
| Warning: | line 647, column 3 Value stored to 'Found' is never read |
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| 1 | //===- ScheduleDAG.cpp - Implement the ScheduleDAG class ------------------===// |
| 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 | /// \file Implements the ScheduleDAG class, which is a base class used by |
| 10 | /// scheduling implementation classes. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "llvm/CodeGen/ScheduleDAG.h" |
| 15 | #include "llvm/ADT/STLExtras.h" |
| 16 | #include "llvm/ADT/SmallVector.h" |
| 17 | #include "llvm/ADT/Statistic.h" |
| 18 | #include "llvm/ADT/iterator_range.h" |
| 19 | #include "llvm/CodeGen/MachineFunction.h" |
| 20 | #include "llvm/CodeGen/ScheduleHazardRecognizer.h" |
| 21 | #include "llvm/CodeGen/SelectionDAGNodes.h" |
| 22 | #include "llvm/CodeGen/TargetInstrInfo.h" |
| 23 | #include "llvm/CodeGen/TargetRegisterInfo.h" |
| 24 | #include "llvm/CodeGen/TargetSubtargetInfo.h" |
| 25 | #include "llvm/Config/llvm-config.h" |
| 26 | #include "llvm/Support/CommandLine.h" |
| 27 | #include "llvm/Support/Compiler.h" |
| 28 | #include "llvm/Support/Debug.h" |
| 29 | #include "llvm/Support/raw_ostream.h" |
| 30 | #include <algorithm> |
| 31 | #include <cassert> |
| 32 | #include <iterator> |
| 33 | #include <limits> |
| 34 | #include <utility> |
| 35 | #include <vector> |
| 36 | |
| 37 | using namespace llvm; |
| 38 | |
| 39 | #define DEBUG_TYPE"pre-RA-sched" "pre-RA-sched" |
| 40 | |
| 41 | STATISTIC(NumNewPredsAdded, "Number of times a single predecessor was added")static llvm::Statistic NumNewPredsAdded = {"pre-RA-sched", "NumNewPredsAdded" , "Number of times a single predecessor was added"}; |
| 42 | STATISTIC(NumTopoInits,static llvm::Statistic NumTopoInits = {"pre-RA-sched", "NumTopoInits" , "Number of times the topological order has been recomputed" } |
| 43 | "Number of times the topological order has been recomputed")static llvm::Statistic NumTopoInits = {"pre-RA-sched", "NumTopoInits" , "Number of times the topological order has been recomputed" }; |
| 44 | |
| 45 | #ifndef NDEBUG1 |
| 46 | static cl::opt<bool> StressSchedOpt( |
| 47 | "stress-sched", cl::Hidden, cl::init(false), |
| 48 | cl::desc("Stress test instruction scheduling")); |
| 49 | #endif |
| 50 | |
| 51 | void SchedulingPriorityQueue::anchor() {} |
| 52 | |
| 53 | ScheduleDAG::ScheduleDAG(MachineFunction &mf) |
| 54 | : TM(mf.getTarget()), TII(mf.getSubtarget().getInstrInfo()), |
| 55 | TRI(mf.getSubtarget().getRegisterInfo()), MF(mf), |
| 56 | MRI(mf.getRegInfo()) { |
| 57 | #ifndef NDEBUG1 |
| 58 | StressSched = StressSchedOpt; |
| 59 | #endif |
| 60 | } |
| 61 | |
| 62 | ScheduleDAG::~ScheduleDAG() = default; |
| 63 | |
| 64 | void ScheduleDAG::clearDAG() { |
| 65 | SUnits.clear(); |
| 66 | EntrySU = SUnit(); |
| 67 | ExitSU = SUnit(); |
| 68 | } |
| 69 | |
| 70 | const MCInstrDesc *ScheduleDAG::getNodeDesc(const SDNode *Node) const { |
| 71 | if (!Node || !Node->isMachineOpcode()) return nullptr; |
| 72 | return &TII->get(Node->getMachineOpcode()); |
| 73 | } |
| 74 | |
| 75 | LLVM_DUMP_METHOD__attribute__((noinline)) void SDep::dump(const TargetRegisterInfo *TRI) const { |
| 76 | switch (getKind()) { |
| 77 | case Data: dbgs() << "Data"; break; |
| 78 | case Anti: dbgs() << "Anti"; break; |
| 79 | case Output: dbgs() << "Out "; break; |
| 80 | case Order: dbgs() << "Ord "; break; |
| 81 | } |
| 82 | |
| 83 | switch (getKind()) { |
| 84 | case Data: |
| 85 | dbgs() << " Latency=" << getLatency(); |
| 86 | if (TRI && isAssignedRegDep()) |
| 87 | dbgs() << " Reg=" << printReg(getReg(), TRI); |
| 88 | break; |
| 89 | case Anti: |
| 90 | case Output: |
| 91 | dbgs() << " Latency=" << getLatency(); |
| 92 | break; |
| 93 | case Order: |
| 94 | dbgs() << " Latency=" << getLatency(); |
| 95 | switch(Contents.OrdKind) { |
| 96 | case Barrier: dbgs() << " Barrier"; break; |
| 97 | case MayAliasMem: |
| 98 | case MustAliasMem: dbgs() << " Memory"; break; |
| 99 | case Artificial: dbgs() << " Artificial"; break; |
| 100 | case Weak: dbgs() << " Weak"; break; |
| 101 | case Cluster: dbgs() << " Cluster"; break; |
| 102 | } |
| 103 | break; |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | bool SUnit::addPred(const SDep &D, bool Required) { |
| 108 | // If this node already has this dependence, don't add a redundant one. |
| 109 | for (SDep &PredDep : Preds) { |
| 110 | // Zero-latency weak edges may be added purely for heuristic ordering. Don't |
| 111 | // add them if another kind of edge already exists. |
| 112 | if (!Required && PredDep.getSUnit() == D.getSUnit()) |
| 113 | return false; |
| 114 | if (PredDep.overlaps(D)) { |
| 115 | // Extend the latency if needed. Equivalent to |
| 116 | // removePred(PredDep) + addPred(D). |
| 117 | if (PredDep.getLatency() < D.getLatency()) { |
| 118 | SUnit *PredSU = PredDep.getSUnit(); |
| 119 | // Find the corresponding successor in N. |
| 120 | SDep ForwardD = PredDep; |
| 121 | ForwardD.setSUnit(this); |
| 122 | for (SDep &SuccDep : PredSU->Succs) { |
| 123 | if (SuccDep == ForwardD) { |
| 124 | SuccDep.setLatency(D.getLatency()); |
| 125 | break; |
| 126 | } |
| 127 | } |
| 128 | PredDep.setLatency(D.getLatency()); |
| 129 | } |
| 130 | return false; |
| 131 | } |
| 132 | } |
| 133 | // Now add a corresponding succ to N. |
| 134 | SDep P = D; |
| 135 | P.setSUnit(this); |
| 136 | SUnit *N = D.getSUnit(); |
| 137 | // Update the bookkeeping. |
| 138 | if (D.getKind() == SDep::Data) { |
| 139 | assert(NumPreds < std::numeric_limits<unsigned>::max() &&((void)0) |
| 140 | "NumPreds will overflow!")((void)0); |
| 141 | assert(N->NumSuccs < std::numeric_limits<unsigned>::max() &&((void)0) |
| 142 | "NumSuccs will overflow!")((void)0); |
| 143 | ++NumPreds; |
| 144 | ++N->NumSuccs; |
| 145 | } |
| 146 | if (!N->isScheduled) { |
| 147 | if (D.isWeak()) { |
| 148 | ++WeakPredsLeft; |
| 149 | } |
| 150 | else { |
| 151 | assert(NumPredsLeft < std::numeric_limits<unsigned>::max() &&((void)0) |
| 152 | "NumPredsLeft will overflow!")((void)0); |
| 153 | ++NumPredsLeft; |
| 154 | } |
| 155 | } |
| 156 | if (!isScheduled) { |
| 157 | if (D.isWeak()) { |
| 158 | ++N->WeakSuccsLeft; |
| 159 | } |
| 160 | else { |
| 161 | assert(N->NumSuccsLeft < std::numeric_limits<unsigned>::max() &&((void)0) |
| 162 | "NumSuccsLeft will overflow!")((void)0); |
| 163 | ++N->NumSuccsLeft; |
| 164 | } |
| 165 | } |
| 166 | Preds.push_back(D); |
| 167 | N->Succs.push_back(P); |
| 168 | if (P.getLatency() != 0) { |
| 169 | this->setDepthDirty(); |
| 170 | N->setHeightDirty(); |
| 171 | } |
| 172 | return true; |
| 173 | } |
| 174 | |
| 175 | void SUnit::removePred(const SDep &D) { |
| 176 | // Find the matching predecessor. |
| 177 | SmallVectorImpl<SDep>::iterator I = llvm::find(Preds, D); |
| 178 | if (I == Preds.end()) |
| 179 | return; |
| 180 | // Find the corresponding successor in N. |
| 181 | SDep P = D; |
| 182 | P.setSUnit(this); |
| 183 | SUnit *N = D.getSUnit(); |
| 184 | SmallVectorImpl<SDep>::iterator Succ = llvm::find(N->Succs, P); |
| 185 | assert(Succ != N->Succs.end() && "Mismatching preds / succs lists!")((void)0); |
| 186 | N->Succs.erase(Succ); |
| 187 | Preds.erase(I); |
| 188 | // Update the bookkeeping. |
| 189 | if (P.getKind() == SDep::Data) { |
| 190 | assert(NumPreds > 0 && "NumPreds will underflow!")((void)0); |
| 191 | assert(N->NumSuccs > 0 && "NumSuccs will underflow!")((void)0); |
| 192 | --NumPreds; |
| 193 | --N->NumSuccs; |
| 194 | } |
| 195 | if (!N->isScheduled) { |
| 196 | if (D.isWeak()) |
| 197 | --WeakPredsLeft; |
| 198 | else { |
| 199 | assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!")((void)0); |
| 200 | --NumPredsLeft; |
| 201 | } |
| 202 | } |
| 203 | if (!isScheduled) { |
| 204 | if (D.isWeak()) |
| 205 | --N->WeakSuccsLeft; |
| 206 | else { |
| 207 | assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!")((void)0); |
| 208 | --N->NumSuccsLeft; |
| 209 | } |
| 210 | } |
| 211 | if (P.getLatency() != 0) { |
| 212 | this->setDepthDirty(); |
| 213 | N->setHeightDirty(); |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | void SUnit::setDepthDirty() { |
| 218 | if (!isDepthCurrent) return; |
| 219 | SmallVector<SUnit*, 8> WorkList; |
| 220 | WorkList.push_back(this); |
| 221 | do { |
| 222 | SUnit *SU = WorkList.pop_back_val(); |
| 223 | SU->isDepthCurrent = false; |
| 224 | for (SDep &SuccDep : SU->Succs) { |
| 225 | SUnit *SuccSU = SuccDep.getSUnit(); |
| 226 | if (SuccSU->isDepthCurrent) |
| 227 | WorkList.push_back(SuccSU); |
| 228 | } |
| 229 | } while (!WorkList.empty()); |
| 230 | } |
| 231 | |
| 232 | void SUnit::setHeightDirty() { |
| 233 | if (!isHeightCurrent) return; |
| 234 | SmallVector<SUnit*, 8> WorkList; |
| 235 | WorkList.push_back(this); |
| 236 | do { |
| 237 | SUnit *SU = WorkList.pop_back_val(); |
| 238 | SU->isHeightCurrent = false; |
| 239 | for (SDep &PredDep : SU->Preds) { |
| 240 | SUnit *PredSU = PredDep.getSUnit(); |
| 241 | if (PredSU->isHeightCurrent) |
| 242 | WorkList.push_back(PredSU); |
| 243 | } |
| 244 | } while (!WorkList.empty()); |
| 245 | } |
| 246 | |
| 247 | void SUnit::setDepthToAtLeast(unsigned NewDepth) { |
| 248 | if (NewDepth <= getDepth()) |
| 249 | return; |
| 250 | setDepthDirty(); |
| 251 | Depth = NewDepth; |
| 252 | isDepthCurrent = true; |
| 253 | } |
| 254 | |
| 255 | void SUnit::setHeightToAtLeast(unsigned NewHeight) { |
| 256 | if (NewHeight <= getHeight()) |
| 257 | return; |
| 258 | setHeightDirty(); |
| 259 | Height = NewHeight; |
| 260 | isHeightCurrent = true; |
| 261 | } |
| 262 | |
| 263 | /// Calculates the maximal path from the node to the exit. |
| 264 | void SUnit::ComputeDepth() { |
| 265 | SmallVector<SUnit*, 8> WorkList; |
| 266 | WorkList.push_back(this); |
| 267 | do { |
| 268 | SUnit *Cur = WorkList.back(); |
| 269 | |
| 270 | bool Done = true; |
| 271 | unsigned MaxPredDepth = 0; |
| 272 | for (const SDep &PredDep : Cur->Preds) { |
| 273 | SUnit *PredSU = PredDep.getSUnit(); |
| 274 | if (PredSU->isDepthCurrent) |
| 275 | MaxPredDepth = std::max(MaxPredDepth, |
| 276 | PredSU->Depth + PredDep.getLatency()); |
| 277 | else { |
| 278 | Done = false; |
| 279 | WorkList.push_back(PredSU); |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | if (Done) { |
| 284 | WorkList.pop_back(); |
| 285 | if (MaxPredDepth != Cur->Depth) { |
| 286 | Cur->setDepthDirty(); |
| 287 | Cur->Depth = MaxPredDepth; |
| 288 | } |
| 289 | Cur->isDepthCurrent = true; |
| 290 | } |
| 291 | } while (!WorkList.empty()); |
| 292 | } |
| 293 | |
| 294 | /// Calculates the maximal path from the node to the entry. |
| 295 | void SUnit::ComputeHeight() { |
| 296 | SmallVector<SUnit*, 8> WorkList; |
| 297 | WorkList.push_back(this); |
| 298 | do { |
| 299 | SUnit *Cur = WorkList.back(); |
| 300 | |
| 301 | bool Done = true; |
| 302 | unsigned MaxSuccHeight = 0; |
| 303 | for (const SDep &SuccDep : Cur->Succs) { |
| 304 | SUnit *SuccSU = SuccDep.getSUnit(); |
| 305 | if (SuccSU->isHeightCurrent) |
| 306 | MaxSuccHeight = std::max(MaxSuccHeight, |
| 307 | SuccSU->Height + SuccDep.getLatency()); |
| 308 | else { |
| 309 | Done = false; |
| 310 | WorkList.push_back(SuccSU); |
| 311 | } |
| 312 | } |
| 313 | |
| 314 | if (Done) { |
| 315 | WorkList.pop_back(); |
| 316 | if (MaxSuccHeight != Cur->Height) { |
| 317 | Cur->setHeightDirty(); |
| 318 | Cur->Height = MaxSuccHeight; |
| 319 | } |
| 320 | Cur->isHeightCurrent = true; |
| 321 | } |
| 322 | } while (!WorkList.empty()); |
| 323 | } |
| 324 | |
| 325 | void SUnit::biasCriticalPath() { |
| 326 | if (NumPreds < 2) |
| 327 | return; |
| 328 | |
| 329 | SUnit::pred_iterator BestI = Preds.begin(); |
| 330 | unsigned MaxDepth = BestI->getSUnit()->getDepth(); |
| 331 | for (SUnit::pred_iterator I = std::next(BestI), E = Preds.end(); I != E; |
| 332 | ++I) { |
| 333 | if (I->getKind() == SDep::Data && I->getSUnit()->getDepth() > MaxDepth) |
| 334 | BestI = I; |
| 335 | } |
| 336 | if (BestI != Preds.begin()) |
| 337 | std::swap(*Preds.begin(), *BestI); |
| 338 | } |
| 339 | |
| 340 | #if !defined(NDEBUG1) || defined(LLVM_ENABLE_DUMP) |
| 341 | LLVM_DUMP_METHOD__attribute__((noinline)) void SUnit::dumpAttributes() const { |
| 342 | dbgs() << " # preds left : " << NumPredsLeft << "\n"; |
| 343 | dbgs() << " # succs left : " << NumSuccsLeft << "\n"; |
| 344 | if (WeakPredsLeft) |
| 345 | dbgs() << " # weak preds left : " << WeakPredsLeft << "\n"; |
| 346 | if (WeakSuccsLeft) |
| 347 | dbgs() << " # weak succs left : " << WeakSuccsLeft << "\n"; |
| 348 | dbgs() << " # rdefs left : " << NumRegDefsLeft << "\n"; |
| 349 | dbgs() << " Latency : " << Latency << "\n"; |
| 350 | dbgs() << " Depth : " << getDepth() << "\n"; |
| 351 | dbgs() << " Height : " << getHeight() << "\n"; |
| 352 | } |
| 353 | |
| 354 | LLVM_DUMP_METHOD__attribute__((noinline)) void ScheduleDAG::dumpNodeName(const SUnit &SU) const { |
| 355 | if (&SU == &EntrySU) |
| 356 | dbgs() << "EntrySU"; |
| 357 | else if (&SU == &ExitSU) |
| 358 | dbgs() << "ExitSU"; |
| 359 | else |
| 360 | dbgs() << "SU(" << SU.NodeNum << ")"; |
| 361 | } |
| 362 | |
| 363 | LLVM_DUMP_METHOD__attribute__((noinline)) void ScheduleDAG::dumpNodeAll(const SUnit &SU) const { |
| 364 | dumpNode(SU); |
| 365 | SU.dumpAttributes(); |
| 366 | if (SU.Preds.size() > 0) { |
| 367 | dbgs() << " Predecessors:\n"; |
| 368 | for (const SDep &Dep : SU.Preds) { |
| 369 | dbgs() << " "; |
| 370 | dumpNodeName(*Dep.getSUnit()); |
| 371 | dbgs() << ": "; |
| 372 | Dep.dump(TRI); |
| 373 | dbgs() << '\n'; |
| 374 | } |
| 375 | } |
| 376 | if (SU.Succs.size() > 0) { |
| 377 | dbgs() << " Successors:\n"; |
| 378 | for (const SDep &Dep : SU.Succs) { |
| 379 | dbgs() << " "; |
| 380 | dumpNodeName(*Dep.getSUnit()); |
| 381 | dbgs() << ": "; |
| 382 | Dep.dump(TRI); |
| 383 | dbgs() << '\n'; |
| 384 | } |
| 385 | } |
| 386 | } |
| 387 | #endif |
| 388 | |
| 389 | #ifndef NDEBUG1 |
| 390 | unsigned ScheduleDAG::VerifyScheduledDAG(bool isBottomUp) { |
| 391 | bool AnyNotSched = false; |
| 392 | unsigned DeadNodes = 0; |
| 393 | for (const SUnit &SUnit : SUnits) { |
| 394 | if (!SUnit.isScheduled) { |
| 395 | if (SUnit.NumPreds == 0 && SUnit.NumSuccs == 0) { |
| 396 | ++DeadNodes; |
| 397 | continue; |
| 398 | } |
| 399 | if (!AnyNotSched) |
| 400 | dbgs() << "*** Scheduling failed! ***\n"; |
| 401 | dumpNode(SUnit); |
| 402 | dbgs() << "has not been scheduled!\n"; |
| 403 | AnyNotSched = true; |
| 404 | } |
| 405 | if (SUnit.isScheduled && |
| 406 | (isBottomUp ? SUnit.getHeight() : SUnit.getDepth()) > |
| 407 | unsigned(std::numeric_limits<int>::max())) { |
| 408 | if (!AnyNotSched) |
| 409 | dbgs() << "*** Scheduling failed! ***\n"; |
| 410 | dumpNode(SUnit); |
| 411 | dbgs() << "has an unexpected " |
| 412 | << (isBottomUp ? "Height" : "Depth") << " value!\n"; |
| 413 | AnyNotSched = true; |
| 414 | } |
| 415 | if (isBottomUp) { |
| 416 | if (SUnit.NumSuccsLeft != 0) { |
| 417 | if (!AnyNotSched) |
| 418 | dbgs() << "*** Scheduling failed! ***\n"; |
| 419 | dumpNode(SUnit); |
| 420 | dbgs() << "has successors left!\n"; |
| 421 | AnyNotSched = true; |
| 422 | } |
| 423 | } else { |
| 424 | if (SUnit.NumPredsLeft != 0) { |
| 425 | if (!AnyNotSched) |
| 426 | dbgs() << "*** Scheduling failed! ***\n"; |
| 427 | dumpNode(SUnit); |
| 428 | dbgs() << "has predecessors left!\n"; |
| 429 | AnyNotSched = true; |
| 430 | } |
| 431 | } |
| 432 | } |
| 433 | assert(!AnyNotSched)((void)0); |
| 434 | return SUnits.size() - DeadNodes; |
| 435 | } |
| 436 | #endif |
| 437 | |
| 438 | void ScheduleDAGTopologicalSort::InitDAGTopologicalSorting() { |
| 439 | // The idea of the algorithm is taken from |
| 440 | // "Online algorithms for managing the topological order of |
| 441 | // a directed acyclic graph" by David J. Pearce and Paul H.J. Kelly |
| 442 | // This is the MNR algorithm, which was first introduced by |
| 443 | // A. Marchetti-Spaccamela, U. Nanni and H. Rohnert in |
| 444 | // "Maintaining a topological order under edge insertions". |
| 445 | // |
| 446 | // Short description of the algorithm: |
| 447 | // |
| 448 | // Topological ordering, ord, of a DAG maps each node to a topological |
| 449 | // index so that for all edges X->Y it is the case that ord(X) < ord(Y). |
| 450 | // |
| 451 | // This means that if there is a path from the node X to the node Z, |
| 452 | // then ord(X) < ord(Z). |
| 453 | // |
| 454 | // This property can be used to check for reachability of nodes: |
| 455 | // if Z is reachable from X, then an insertion of the edge Z->X would |
| 456 | // create a cycle. |
| 457 | // |
| 458 | // The algorithm first computes a topological ordering for the DAG by |
| 459 | // initializing the Index2Node and Node2Index arrays and then tries to keep |
| 460 | // the ordering up-to-date after edge insertions by reordering the DAG. |
| 461 | // |
| 462 | // On insertion of the edge X->Y, the algorithm first marks by calling DFS |
| 463 | // the nodes reachable from Y, and then shifts them using Shift to lie |
| 464 | // immediately after X in Index2Node. |
| 465 | |
| 466 | // Cancel pending updates, mark as valid. |
| 467 | Dirty = false; |
| 468 | Updates.clear(); |
| 469 | |
| 470 | unsigned DAGSize = SUnits.size(); |
| 471 | std::vector<SUnit*> WorkList; |
| 472 | WorkList.reserve(DAGSize); |
| 473 | |
| 474 | Index2Node.resize(DAGSize); |
| 475 | Node2Index.resize(DAGSize); |
| 476 | |
| 477 | // Initialize the data structures. |
| 478 | if (ExitSU) |
| 479 | WorkList.push_back(ExitSU); |
| 480 | for (SUnit &SU : SUnits) { |
| 481 | int NodeNum = SU.NodeNum; |
| 482 | unsigned Degree = SU.Succs.size(); |
| 483 | // Temporarily use the Node2Index array as scratch space for degree counts. |
| 484 | Node2Index[NodeNum] = Degree; |
| 485 | |
| 486 | // Is it a node without dependencies? |
| 487 | if (Degree == 0) { |
| 488 | assert(SU.Succs.empty() && "SUnit should have no successors")((void)0); |
| 489 | // Collect leaf nodes. |
| 490 | WorkList.push_back(&SU); |
| 491 | } |
| 492 | } |
| 493 | |
| 494 | int Id = DAGSize; |
| 495 | while (!WorkList.empty()) { |
| 496 | SUnit *SU = WorkList.back(); |
| 497 | WorkList.pop_back(); |
| 498 | if (SU->NodeNum < DAGSize) |
| 499 | Allocate(SU->NodeNum, --Id); |
| 500 | for (const SDep &PredDep : SU->Preds) { |
| 501 | SUnit *SU = PredDep.getSUnit(); |
| 502 | if (SU->NodeNum < DAGSize && !--Node2Index[SU->NodeNum]) |
| 503 | // If all dependencies of the node are processed already, |
| 504 | // then the node can be computed now. |
| 505 | WorkList.push_back(SU); |
| 506 | } |
| 507 | } |
| 508 | |
| 509 | Visited.resize(DAGSize); |
| 510 | NumTopoInits++; |
| 511 | |
| 512 | #ifndef NDEBUG1 |
| 513 | // Check correctness of the ordering |
| 514 | for (SUnit &SU : SUnits) { |
| 515 | for (const SDep &PD : SU.Preds) { |
| 516 | assert(Node2Index[SU.NodeNum] > Node2Index[PD.getSUnit()->NodeNum] &&((void)0) |
| 517 | "Wrong topological sorting")((void)0); |
| 518 | } |
| 519 | } |
| 520 | #endif |
| 521 | } |
| 522 | |
| 523 | void ScheduleDAGTopologicalSort::FixOrder() { |
| 524 | // Recompute from scratch after new nodes have been added. |
| 525 | if (Dirty) { |
| 526 | InitDAGTopologicalSorting(); |
| 527 | return; |
| 528 | } |
| 529 | |
| 530 | // Otherwise apply updates one-by-one. |
| 531 | for (auto &U : Updates) |
| 532 | AddPred(U.first, U.second); |
| 533 | Updates.clear(); |
| 534 | } |
| 535 | |
| 536 | void ScheduleDAGTopologicalSort::AddPredQueued(SUnit *Y, SUnit *X) { |
| 537 | // Recomputing the order from scratch is likely more efficient than applying |
| 538 | // updates one-by-one for too many updates. The current cut-off is arbitrarily |
| 539 | // chosen. |
| 540 | Dirty = Dirty || Updates.size() > 10; |
| 541 | |
| 542 | if (Dirty) |
| 543 | return; |
| 544 | |
| 545 | Updates.emplace_back(Y, X); |
| 546 | } |
| 547 | |
| 548 | void ScheduleDAGTopologicalSort::AddPred(SUnit *Y, SUnit *X) { |
| 549 | int UpperBound, LowerBound; |
| 550 | LowerBound = Node2Index[Y->NodeNum]; |
| 551 | UpperBound = Node2Index[X->NodeNum]; |
| 552 | bool HasLoop = false; |
| 553 | // Is Ord(X) < Ord(Y) ? |
| 554 | if (LowerBound < UpperBound) { |
| 555 | // Update the topological order. |
| 556 | Visited.reset(); |
| 557 | DFS(Y, UpperBound, HasLoop); |
| 558 | assert(!HasLoop && "Inserted edge creates a loop!")((void)0); |
| 559 | // Recompute topological indexes. |
| 560 | Shift(Visited, LowerBound, UpperBound); |
| 561 | } |
| 562 | |
| 563 | NumNewPredsAdded++; |
| 564 | } |
| 565 | |
| 566 | void ScheduleDAGTopologicalSort::RemovePred(SUnit *M, SUnit *N) { |
| 567 | // InitDAGTopologicalSorting(); |
| 568 | } |
| 569 | |
| 570 | void ScheduleDAGTopologicalSort::DFS(const SUnit *SU, int UpperBound, |
| 571 | bool &HasLoop) { |
| 572 | std::vector<const SUnit*> WorkList; |
| 573 | WorkList.reserve(SUnits.size()); |
| 574 | |
| 575 | WorkList.push_back(SU); |
| 576 | do { |
| 577 | SU = WorkList.back(); |
| 578 | WorkList.pop_back(); |
| 579 | Visited.set(SU->NodeNum); |
| 580 | for (const SDep &SuccDep |
| 581 | : make_range(SU->Succs.rbegin(), SU->Succs.rend())) { |
| 582 | unsigned s = SuccDep.getSUnit()->NodeNum; |
| 583 | // Edges to non-SUnits are allowed but ignored (e.g. ExitSU). |
| 584 | if (s >= Node2Index.size()) |
| 585 | continue; |
| 586 | if (Node2Index[s] == UpperBound) { |
| 587 | HasLoop = true; |
| 588 | return; |
| 589 | } |
| 590 | // Visit successors if not already and in affected region. |
| 591 | if (!Visited.test(s) && Node2Index[s] < UpperBound) { |
| 592 | WorkList.push_back(SuccDep.getSUnit()); |
| 593 | } |
| 594 | } |
| 595 | } while (!WorkList.empty()); |
| 596 | } |
| 597 | |
| 598 | std::vector<int> ScheduleDAGTopologicalSort::GetSubGraph(const SUnit &StartSU, |
| 599 | const SUnit &TargetSU, |
| 600 | bool &Success) { |
| 601 | std::vector<const SUnit*> WorkList; |
| 602 | int LowerBound = Node2Index[StartSU.NodeNum]; |
| 603 | int UpperBound = Node2Index[TargetSU.NodeNum]; |
| 604 | bool Found = false; |
| 605 | BitVector VisitedBack; |
| 606 | std::vector<int> Nodes; |
| 607 | |
| 608 | if (LowerBound > UpperBound) { |
| 609 | Success = false; |
| 610 | return Nodes; |
| 611 | } |
| 612 | |
| 613 | WorkList.reserve(SUnits.size()); |
| 614 | Visited.reset(); |
| 615 | |
| 616 | // Starting from StartSU, visit all successors up |
| 617 | // to UpperBound. |
| 618 | WorkList.push_back(&StartSU); |
| 619 | do { |
| 620 | const SUnit *SU = WorkList.back(); |
| 621 | WorkList.pop_back(); |
| 622 | for (int I = SU->Succs.size()-1; I >= 0; --I) { |
| 623 | const SUnit *Succ = SU->Succs[I].getSUnit(); |
| 624 | unsigned s = Succ->NodeNum; |
| 625 | // Edges to non-SUnits are allowed but ignored (e.g. ExitSU). |
| 626 | if (Succ->isBoundaryNode()) |
| 627 | continue; |
| 628 | if (Node2Index[s] == UpperBound) { |
| 629 | Found = true; |
| 630 | continue; |
| 631 | } |
| 632 | // Visit successors if not already and in affected region. |
| 633 | if (!Visited.test(s) && Node2Index[s] < UpperBound) { |
| 634 | Visited.set(s); |
| 635 | WorkList.push_back(Succ); |
| 636 | } |
| 637 | } |
| 638 | } while (!WorkList.empty()); |
| 639 | |
| 640 | if (!Found) { |
| 641 | Success = false; |
| 642 | return Nodes; |
| 643 | } |
| 644 | |
| 645 | WorkList.clear(); |
| 646 | VisitedBack.resize(SUnits.size()); |
| 647 | Found = false; |
Value stored to 'Found' is never read | |
| 648 | |
| 649 | // Starting from TargetSU, visit all predecessors up |
| 650 | // to LowerBound. SUs that are visited by the two |
| 651 | // passes are added to Nodes. |
| 652 | WorkList.push_back(&TargetSU); |
| 653 | do { |
| 654 | const SUnit *SU = WorkList.back(); |
| 655 | WorkList.pop_back(); |
| 656 | for (int I = SU->Preds.size()-1; I >= 0; --I) { |
| 657 | const SUnit *Pred = SU->Preds[I].getSUnit(); |
| 658 | unsigned s = Pred->NodeNum; |
| 659 | // Edges to non-SUnits are allowed but ignored (e.g. EntrySU). |
| 660 | if (Pred->isBoundaryNode()) |
| 661 | continue; |
| 662 | if (Node2Index[s] == LowerBound) { |
| 663 | Found = true; |
| 664 | continue; |
| 665 | } |
| 666 | if (!VisitedBack.test(s) && Visited.test(s)) { |
| 667 | VisitedBack.set(s); |
| 668 | WorkList.push_back(Pred); |
| 669 | Nodes.push_back(s); |
| 670 | } |
| 671 | } |
| 672 | } while (!WorkList.empty()); |
| 673 | |
| 674 | assert(Found && "Error in SUnit Graph!")((void)0); |
| 675 | Success = true; |
| 676 | return Nodes; |
| 677 | } |
| 678 | |
| 679 | void ScheduleDAGTopologicalSort::Shift(BitVector& Visited, int LowerBound, |
| 680 | int UpperBound) { |
| 681 | std::vector<int> L; |
| 682 | int shift = 0; |
| 683 | int i; |
| 684 | |
| 685 | for (i = LowerBound; i <= UpperBound; ++i) { |
| 686 | // w is node at topological index i. |
| 687 | int w = Index2Node[i]; |
| 688 | if (Visited.test(w)) { |
| 689 | // Unmark. |
| 690 | Visited.reset(w); |
| 691 | L.push_back(w); |
| 692 | shift = shift + 1; |
| 693 | } else { |
| 694 | Allocate(w, i - shift); |
| 695 | } |
| 696 | } |
| 697 | |
| 698 | for (unsigned LI : L) { |
| 699 | Allocate(LI, i - shift); |
| 700 | i = i + 1; |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | bool ScheduleDAGTopologicalSort::WillCreateCycle(SUnit *TargetSU, SUnit *SU) { |
| 705 | FixOrder(); |
| 706 | // Is SU reachable from TargetSU via successor edges? |
| 707 | if (IsReachable(SU, TargetSU)) |
| 708 | return true; |
| 709 | for (const SDep &PredDep : TargetSU->Preds) |
| 710 | if (PredDep.isAssignedRegDep() && |
| 711 | IsReachable(SU, PredDep.getSUnit())) |
| 712 | return true; |
| 713 | return false; |
| 714 | } |
| 715 | |
| 716 | void ScheduleDAGTopologicalSort::AddSUnitWithoutPredecessors(const SUnit *SU) { |
| 717 | assert(SU->NodeNum == Index2Node.size() && "Node cannot be added at the end")((void)0); |
| 718 | assert(SU->NumPreds == 0 && "Can only add SU's with no predecessors")((void)0); |
| 719 | Node2Index.push_back(Index2Node.size()); |
| 720 | Index2Node.push_back(SU->NodeNum); |
| 721 | Visited.resize(Node2Index.size()); |
| 722 | } |
| 723 | |
| 724 | bool ScheduleDAGTopologicalSort::IsReachable(const SUnit *SU, |
| 725 | const SUnit *TargetSU) { |
| 726 | FixOrder(); |
| 727 | // If insertion of the edge SU->TargetSU would create a cycle |
| 728 | // then there is a path from TargetSU to SU. |
| 729 | int UpperBound, LowerBound; |
| 730 | LowerBound = Node2Index[TargetSU->NodeNum]; |
| 731 | UpperBound = Node2Index[SU->NodeNum]; |
| 732 | bool HasLoop = false; |
| 733 | // Is Ord(TargetSU) < Ord(SU) ? |
| 734 | if (LowerBound < UpperBound) { |
| 735 | Visited.reset(); |
| 736 | // There may be a path from TargetSU to SU. Check for it. |
| 737 | DFS(TargetSU, UpperBound, HasLoop); |
| 738 | } |
| 739 | return HasLoop; |
| 740 | } |
| 741 | |
| 742 | void ScheduleDAGTopologicalSort::Allocate(int n, int index) { |
| 743 | Node2Index[n] = index; |
| 744 | Index2Node[index] = n; |
| 745 | } |
| 746 | |
| 747 | ScheduleDAGTopologicalSort:: |
| 748 | ScheduleDAGTopologicalSort(std::vector<SUnit> &sunits, SUnit *exitsu) |
| 749 | : SUnits(sunits), ExitSU(exitsu) {} |
| 750 | |
| 751 | ScheduleHazardRecognizer::~ScheduleHazardRecognizer() = default; |