/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/CodeGen/SelectionDAGNodes.h

Bug Summary

File:	src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/CodeGen/SelectionDAGNodes.h
Warning:	line 1114, column 10 Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name X86SelectionDAGInfo.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I 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/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData/Coverage -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/CodeView -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/DWARF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/MSF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/PDB -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Demangle -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/JITLink -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/Orc -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenACC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenMP -I /include/llvm/CodeGen/GlobalISel -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IRReader -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/LTO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Linker -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC/MCParser -I /include/llvm/CodeGen/MIRParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Object -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Option -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Passes -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Scalar -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ADT -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/Symbolize -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Target -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Utils -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Vectorize -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/IPO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libLLVM/../include -I /usr/src/gnu/usr.bin/clang/libLLVM/obj -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -D PIC -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -D_RET_PROTECTOR -ret-protector -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86/X86SelectionDAGInfo.cpp

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86/X86SelectionDAGInfo.cpp

→

1//===-- X86SelectionDAGInfo.cpp - X86 SelectionDAG Info -------------------===//
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 file implements the X86SelectionDAGInfo class.
10//
11//===----------------------------------------------------------------------===//

13#include "X86SelectionDAGInfo.h"
14#include "X86ISelLowering.h"
15#include "X86InstrInfo.h"
16#include "X86RegisterInfo.h"
17#include "X86Subtarget.h"
18#include "llvm/CodeGen/MachineFrameInfo.h"
19#include "llvm/CodeGen/SelectionDAG.h"
20#include "llvm/CodeGen/TargetLowering.h"
21#include "llvm/IR/DerivedTypes.h"

23using namespace llvm;

25#define DEBUG_TYPE"x86-selectiondag-info" "x86-selectiondag-info"

27static cl::opt<bool>
  UseFSRMForMemcpy("x86-use-fsrm-for-memcpy", cl::Hidden, cl::init(false),
                   cl::desc("Use fast short rep mov in memcpy lowering"));

31bool X86SelectionDAGInfo::isBaseRegConflictPossible(
  SelectionDAG &DAG, ArrayRef<MCPhysReg> ClobberSet) const {
// We cannot use TRI->hasBasePointer() until *after* we select all basic
// blocks.  Legalization may introduce new stack temporaries with large
// alignment requirements.  Fall back to generic code if there are any
// dynamic stack adjustments (hopefully rare) and the base pointer would
// conflict if we had to use it.
MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
if (!MFI.hasVarSizedObjects() && !MFI.hasOpaqueSPAdjustment())
  return false;

const X86RegisterInfo *TRI = static_cast<const X86RegisterInfo *>(
    DAG.getSubtarget().getRegisterInfo());
return llvm::is_contained(ClobberSet, TRI->getBaseRegister());
45}

47SDValue X86SelectionDAGInfo::EmitTargetCodeForMemset(
  SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Val,
  SDValue Size, Align Alignment, bool isVolatile,
  MachinePointerInfo DstPtrInfo) const {
ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
const X86Subtarget &Subtarget =
    DAG.getMachineFunction().getSubtarget<X86Subtarget>();

55#ifndef NDEBUG1
// If the base register might conflict with our physical registers, bail out.
const MCPhysReg ClobberSet[] = {X86::RCX, X86::RAX, X86::RDI,
                                X86::ECX, X86::EAX, X86::EDI};
assert(!isBaseRegConflictPossible(DAG, ClobberSet))((void)0);
60#endif

// If to a segment-relative address space, use the default lowering.
if (DstPtrInfo.getAddrSpace() >= 256)
1
Assuming the condition is false→
2
←
Taking false branch→
  return SDValue();

// If not DWORD aligned or size is more than the threshold, call the library.
// The libc version is likely to be faster for these cases. It can use the
// address value and run time information about the CPU.
if (Alignment < Align(4) || !ConstantSize ||
3
←
Assuming 'ConstantSize' is non-null→
5
←
Taking false branch→
    ConstantSize->getZExtValue() > Subtarget.getMaxInlineSizeThreshold()) {
4
←
Assuming the condition is false→
  // Check to see if there is a specialized entry-point for memory zeroing.
  ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);

  if (const char *bzeroName = (ValC && ValC->isNullValue())
      ? DAG.getTargetLoweringInfo().getLibcallName(RTLIB::BZERO)
      : nullptr) {
    const TargetLowering &TLI = DAG.getTargetLoweringInfo();
    EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
    Type *IntPtrTy = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
    TargetLowering::ArgListTy Args;
    TargetLowering::ArgListEntry Entry;
    Entry.Node = Dst;
    Entry.Ty = IntPtrTy;
    Args.push_back(Entry);
    Entry.Node = Size;
    Args.push_back(Entry);

    TargetLowering::CallLoweringInfo CLI(DAG);
    CLI.setDebugLoc(dl)
        .setChain(Chain)
        .setLibCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
                      DAG.getExternalSymbol(bzeroName, IntPtr),
                      std::move(Args))
        .setDiscardResult();

    std::pair<SDValue,SDValue> CallResult = TLI.LowerCallTo(CLI);
    return CallResult.second;
  }

  // Otherwise have the target-independent code call memset.
  return SDValue();
}

uint64_t SizeVal = ConstantSize->getZExtValue();
SDValue InFlag;
EVT AVT;
SDValue Count;
ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);
unsigned BytesLeft = 0;
if (ValC) {
6
←
Assuming 'ValC' is null→
7
←
Taking false branch→
  unsigned ValReg;
  uint64_t Val = ValC->getZExtValue() & 255;

  // If the value is a constant, then we can potentially use larger sets.
  if (Alignment > Align(2)) {
    // DWORD aligned
    AVT = MVT::i32;
    ValReg = X86::EAX;
    Val = (Val << 8)  | Val;
    Val = (Val << 16) | Val;
    if (Subtarget.is64Bit() && Alignment > Align(8)) { // QWORD aligned
      AVT = MVT::i64;
      ValReg = X86::RAX;
      Val = (Val << 32) | Val;
    }
  } else if (Alignment == Align(2)) {
    // WORD aligned
    AVT = MVT::i16;
    ValReg = X86::AX;
    Val = (Val << 8) | Val;
  } else {
    // Byte aligned
    AVT = MVT::i8;
    ValReg = X86::AL;
    Count = DAG.getIntPtrConstant(SizeVal, dl);
  }

  if (AVT.bitsGT(MVT::i8)) {
    unsigned UBytes = AVT.getSizeInBits() / 8;
    Count = DAG.getIntPtrConstant(SizeVal / UBytes, dl);
    BytesLeft = SizeVal % UBytes;
  }

  Chain = DAG.getCopyToReg(Chain, dl, ValReg, DAG.getConstant(Val, dl, AVT),
                           InFlag);
  InFlag = Chain.getValue(1);
} else {
  AVT = MVT::i8;
  Count  = DAG.getIntPtrConstant(SizeVal, dl);
  Chain  = DAG.getCopyToReg(Chain, dl, X86::AL, Val, InFlag);
8
←
Value assigned to 'N.Node'→
9
←
Calling 'SelectionDAG::getCopyToReg'→
  InFlag = Chain.getValue(1);
}

bool Use64BitRegs = Subtarget.isTarget64BitLP64();
Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RCX : X86::ECX,
                         Count, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, dl, Use64BitRegs ? X86::RDI : X86::EDI,
                         Dst, InFlag);
InFlag = Chain.getValue(1);

SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
SDValue Ops[] = { Chain, DAG.getValueType(AVT), InFlag };
Chain = DAG.getNode(X86ISD::REP_STOS, dl, Tys, Ops);

if (BytesLeft) {
  // Handle the last 1 - 7 bytes.
  unsigned Offset = SizeVal - BytesLeft;
  EVT AddrVT = Dst.getValueType();
  EVT SizeVT = Size.getValueType();

  Chain =
      DAG.getMemset(Chain, dl,
                    DAG.getNode(ISD::ADD, dl, AddrVT, Dst,
                                DAG.getConstant(Offset, dl, AddrVT)),
                    Val, DAG.getConstant(BytesLeft, dl, SizeVT), Alignment,
                    isVolatile, false, DstPtrInfo.getWithOffset(Offset));
}

// TODO: Use a Tokenfactor, as in memcpy, instead of a single chain.
return Chain;
182}

184/// Emit a single REP MOVS{B,W,D,Q} instruction.
185static SDValue emitRepmovs(const X86Subtarget &Subtarget, SelectionDAG &DAG,
                         const SDLoc &dl, SDValue Chain, SDValue Dst,
                         SDValue Src, SDValue Size, MVT AVT) {
const bool Use64BitRegs = Subtarget.isTarget64BitLP64();
const unsigned CX = Use64BitRegs ? X86::RCX : X86::ECX;
const unsigned DI = Use64BitRegs ? X86::RDI : X86::EDI;
const unsigned SI = Use64BitRegs ? X86::RSI : X86::ESI;

SDValue InFlag;
Chain = DAG.getCopyToReg(Chain, dl, CX, Size, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, dl, DI, Dst, InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, dl, SI, Src, InFlag);
InFlag = Chain.getValue(1);

SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
SDValue Ops[] = {Chain, DAG.getValueType(AVT), InFlag};
return DAG.getNode(X86ISD::REP_MOVS, dl, Tys, Ops);
204}

206/// Emit a single REP MOVSB instruction for a particular constant size.
207static SDValue emitRepmovsB(const X86Subtarget &Subtarget, SelectionDAG &DAG,
                          const SDLoc &dl, SDValue Chain, SDValue Dst,
                          SDValue Src, uint64_t Size) {
return emitRepmovs(Subtarget, DAG, dl, Chain, Dst, Src,
                   DAG.getIntPtrConstant(Size, dl), MVT::i8);
212}

214/// Returns the best type to use with repmovs depending on alignment.
215static MVT getOptimalRepmovsType(const X86Subtarget &Subtarget,
                               uint64_t Align) {
assert((Align != 0) && "Align is normalized")((void)0);
assert(isPowerOf2_64(Align) && "Align is a power of 2")((void)0);
switch (Align) {
case 1:
  return MVT::i8;
case 2:
  return MVT::i16;
case 4:
  return MVT::i32;
default:
  return Subtarget.is64Bit() ? MVT::i64 : MVT::i32;
}
229}

231/// Returns a REP MOVS instruction, possibly with a few load/stores to implement
232/// a constant size memory copy. In some cases where we know REP MOVS is
233/// inefficient we return an empty SDValue so the calling code can either
234/// generate a load/store sequence or call the runtime memcpy function.
235static SDValue emitConstantSizeRepmov(
  SelectionDAG &DAG, const X86Subtarget &Subtarget, const SDLoc &dl,
  SDValue Chain, SDValue Dst, SDValue Src, uint64_t Size, EVT SizeVT,
  unsigned Align, bool isVolatile, bool AlwaysInline,
  MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) {

/// TODO: Revisit next line: big copy with ERMSB on march >= haswell are very
/// efficient.
if (!AlwaysInline && Size > Subtarget.getMaxInlineSizeThreshold())
  return SDValue();

/// If we have enhanced repmovs we use it.
if (Subtarget.hasERMSB())
  return emitRepmovsB(Subtarget, DAG, dl, Chain, Dst, Src, Size);

assert(!Subtarget.hasERMSB() && "No efficient RepMovs")((void)0);
/// We assume runtime memcpy will do a better job for unaligned copies when
/// ERMS is not present.
if (!AlwaysInline && (Align & 3) != 0)
  return SDValue();

const MVT BlockType = getOptimalRepmovsType(Subtarget, Align);
const uint64_t BlockBytes = BlockType.getSizeInBits() / 8;
const uint64_t BlockCount = Size / BlockBytes;
const uint64_t BytesLeft = Size % BlockBytes;
SDValue RepMovs =
    emitRepmovs(Subtarget, DAG, dl, Chain, Dst, Src,
                DAG.getIntPtrConstant(BlockCount, dl), BlockType);

/// RepMov can process the whole length.
if (BytesLeft == 0)
  return RepMovs;

assert(BytesLeft && "We have leftover at this point")((void)0);

/// In case we optimize for size we use repmovsb even if it's less efficient
/// so we can save the loads/stores of the leftover.
if (DAG.getMachineFunction().getFunction().hasMinSize())
  return emitRepmovsB(Subtarget, DAG, dl, Chain, Dst, Src, Size);

// Handle the last 1 - 7 bytes.
SmallVector<SDValue, 4> Results;
Results.push_back(RepMovs);
unsigned Offset = Size - BytesLeft;
EVT DstVT = Dst.getValueType();
EVT SrcVT = Src.getValueType();
Results.push_back(DAG.getMemcpy(
    Chain, dl,
    DAG.getNode(ISD::ADD, dl, DstVT, Dst, DAG.getConstant(Offset, dl, DstVT)),
    DAG.getNode(ISD::ADD, dl, SrcVT, Src, DAG.getConstant(Offset, dl, SrcVT)),
    DAG.getConstant(BytesLeft, dl, SizeVT), llvm::Align(Align), isVolatile,
    /*AlwaysInline*/ true, /*isTailCall*/ false,
    DstPtrInfo.getWithOffset(Offset), SrcPtrInfo.getWithOffset(Offset)));
return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Results);
289}

291SDValue X86SelectionDAGInfo::EmitTargetCodeForMemcpy(
  SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
  SDValue Size, Align Alignment, bool isVolatile, bool AlwaysInline,
  MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
// If to a segment-relative address space, use the default lowering.
if (DstPtrInfo.getAddrSpace() >= 256 || SrcPtrInfo.getAddrSpace() >= 256)
  return SDValue();

// If the base registers conflict with our physical registers, use the default
// lowering.
const MCPhysReg ClobberSet[] = {X86::RCX, X86::RSI, X86::RDI,
                                X86::ECX, X86::ESI, X86::EDI};
if (isBaseRegConflictPossible(DAG, ClobberSet))
  return SDValue();

const X86Subtarget &Subtarget =
    DAG.getMachineFunction().getSubtarget<X86Subtarget>();

// If enabled and available, use fast short rep mov.
if (UseFSRMForMemcpy && Subtarget.hasFSRM())
  return emitRepmovs(Subtarget, DAG, dl, Chain, Dst, Src, Size, MVT::i8);

/// Handle constant sizes,
if (ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size))
  return emitConstantSizeRepmov(
      DAG, Subtarget, dl, Chain, Dst, Src, ConstantSize->getZExtValue(),
      Size.getValueType(), Alignment.value(), isVolatile, AlwaysInline,
      DstPtrInfo, SrcPtrInfo);

return SDValue();
321}

←

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/CodeGen/SelectionDAG.h

→

1//===- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ----------*- C++ -*-===//
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 file declares the SelectionDAG class, and transitively defines the
10// SDNode class and subclasses.
11//
12//===----------------------------------------------------------------------===//

14#ifndef LLVM_CODEGEN_SELECTIONDAG_H
15#define LLVM_CODEGEN_SELECTIONDAG_H

17#include "llvm/ADT/APFloat.h"
18#include "llvm/ADT/APInt.h"
19#include "llvm/ADT/ArrayRef.h"
20#include "llvm/ADT/DenseMap.h"
21#include "llvm/ADT/DenseSet.h"
22#include "llvm/ADT/FoldingSet.h"
23#include "llvm/ADT/SetVector.h"
24#include "llvm/ADT/SmallVector.h"
25#include "llvm/ADT/StringMap.h"
26#include "llvm/ADT/ilist.h"
27#include "llvm/ADT/iterator.h"
28#include "llvm/ADT/iterator_range.h"
29#include "llvm/CodeGen/DAGCombine.h"
30#include "llvm/CodeGen/ISDOpcodes.h"
31#include "llvm/CodeGen/MachineFunction.h"
32#include "llvm/CodeGen/MachineMemOperand.h"
33#include "llvm/CodeGen/SelectionDAGNodes.h"
34#include "llvm/CodeGen/ValueTypes.h"
35#include "llvm/IR/DebugLoc.h"
36#include "llvm/IR/Instructions.h"
37#include "llvm/IR/Metadata.h"
38#include "llvm/Support/Allocator.h"
39#include "llvm/Support/ArrayRecycler.h"
40#include "llvm/Support/AtomicOrdering.h"
41#include "llvm/Support/Casting.h"
42#include "llvm/Support/CodeGen.h"
43#include "llvm/Support/ErrorHandling.h"
44#include "llvm/Support/MachineValueType.h"
45#include "llvm/Support/RecyclingAllocator.h"
46#include <algorithm>
47#include <cassert>
48#include <cstdint>
49#include <functional>
50#include <map>
51#include <string>
52#include <tuple>
53#include <utility>
54#include <vector>

56namespace llvm {

58class AAResults;
59class BlockAddress;
60class BlockFrequencyInfo;
61class Constant;
62class ConstantFP;
63class ConstantInt;
64class DataLayout;
65struct fltSemantics;
66class FunctionLoweringInfo;
67class GlobalValue;
68struct KnownBits;
69class LegacyDivergenceAnalysis;
70class LLVMContext;
71class MachineBasicBlock;
72class MachineConstantPoolValue;
73class MCSymbol;
74class OptimizationRemarkEmitter;
75class ProfileSummaryInfo;
76class SDDbgValue;
77class SDDbgOperand;
78class SDDbgLabel;
79class SelectionDAG;
80class SelectionDAGTargetInfo;
81class TargetLibraryInfo;
82class TargetLowering;
83class TargetMachine;
84class TargetSubtargetInfo;
85class Value;

87class SDVTListNode : public FoldingSetNode {
friend struct FoldingSetTrait<SDVTListNode>;

/// A reference to an Interned FoldingSetNodeID for this node.
/// The Allocator in SelectionDAG holds the data.
/// SDVTList contains all types which are frequently accessed in SelectionDAG.
/// The size of this list is not expected to be big so it won't introduce
/// a memory penalty.
FoldingSetNodeIDRef FastID;
const EVT *VTs;
unsigned int NumVTs;
/// The hash value for SDVTList is fixed, so cache it to avoid
/// hash calculation.
unsigned HashValue;

102public:
SDVTListNode(const FoldingSetNodeIDRef ID, const EVT *VT, unsigned int Num) :
    FastID(ID), VTs(VT), NumVTs(Num) {
  HashValue = ID.ComputeHash();
}

SDVTList getSDVTList() {
  SDVTList result = {VTs, NumVTs};
  return result;
}
112};

114/// Specialize FoldingSetTrait for SDVTListNode
115/// to avoid computing temp FoldingSetNodeID and hash value.
116template<> struct FoldingSetTrait<SDVTListNode> : DefaultFoldingSetTrait<SDVTListNode> {
static void Profile(const SDVTListNode &X, FoldingSetNodeID& ID) {
  ID = X.FastID;
}

static bool Equals(const SDVTListNode &X, const FoldingSetNodeID &ID,
                   unsigned IDHash, FoldingSetNodeID &TempID) {
  if (X.HashValue != IDHash)
    return false;
  return ID == X.FastID;
}

static unsigned ComputeHash(const SDVTListNode &X, FoldingSetNodeID &TempID) {
  return X.HashValue;
}
131};

133template <> struct ilist_alloc_traits<SDNode> {
static void deleteNode(SDNode *) {
  llvm_unreachable("ilist_traits<SDNode> shouldn't see a deleteNode call!")__builtin_unreachable();
}
137};

139/// Keeps track of dbg_value information through SDISel.  We do
140/// not build SDNodes for these so as not to perturb the generated code;
141/// instead the info is kept off to the side in this structure. Each SDNode may
142/// have one or more associated dbg_value entries. This information is kept in
143/// DbgValMap.
144/// Byval parameters are handled separately because they don't use alloca's,
145/// which busts the normal mechanism.  There is good reason for handling all
146/// parameters separately:  they may not have code generated for them, they
147/// should always go at the beginning of the function regardless of other code
148/// motion, and debug info for them is potentially useful even if the parameter
149/// is unused.  Right now only byval parameters are handled separately.
150class SDDbgInfo {
BumpPtrAllocator Alloc;
SmallVector<SDDbgValue*, 32> DbgValues;
SmallVector<SDDbgValue*, 32> ByvalParmDbgValues;
SmallVector<SDDbgLabel*, 4> DbgLabels;
using DbgValMapType = DenseMap<const SDNode *, SmallVector<SDDbgValue *, 2>>;
DbgValMapType DbgValMap;

158public:
SDDbgInfo() = default;
SDDbgInfo(const SDDbgInfo &) = delete;
SDDbgInfo &operator=(const SDDbgInfo &) = delete;

void add(SDDbgValue *V, bool isParameter);

void add(SDDbgLabel *L) { DbgLabels.push_back(L); }

/// Invalidate all DbgValues attached to the node and remove
/// it from the Node-to-DbgValues map.
void erase(const SDNode *Node);

void clear() {
  DbgValMap.clear();
  DbgValues.clear();
  ByvalParmDbgValues.clear();
  DbgLabels.clear();
  Alloc.Reset();
}

BumpPtrAllocator &getAlloc() { return Alloc; }

bool empty() const {
  return DbgValues.empty() && ByvalParmDbgValues.empty() && DbgLabels.empty();
}

ArrayRef<SDDbgValue*> getSDDbgValues(const SDNode *Node) const {
  auto I = DbgValMap.find(Node);
  if (I != DbgValMap.end())
    return I->second;
  return ArrayRef<SDDbgValue*>();
}

using DbgIterator = SmallVectorImpl<SDDbgValue*>::iterator;
using DbgLabelIterator = SmallVectorImpl<SDDbgLabel*>::iterator;

DbgIterator DbgBegin() { return DbgValues.begin(); }
DbgIterator DbgEnd()   { return DbgValues.end(); }
DbgIterator ByvalParmDbgBegin() { return ByvalParmDbgValues.begin(); }
DbgIterator ByvalParmDbgEnd()   { return ByvalParmDbgValues.end(); }
DbgLabelIterator DbgLabelBegin() { return DbgLabels.begin(); }
DbgLabelIterator DbgLabelEnd()   { return DbgLabels.end(); }
201};

203void checkForCycles(const SelectionDAG *DAG, bool force = false);

205/// This is used to represent a portion of an LLVM function in a low-level
206/// Data Dependence DAG representation suitable for instruction selection.
207/// This DAG is constructed as the first step of instruction selection in order
208/// to allow implementation of machine specific optimizations
209/// and code simplifications.
210///
211/// The representation used by the SelectionDAG is a target-independent
212/// representation, which has some similarities to the GCC RTL representation,
213/// but is significantly more simple, powerful, and is a graph form instead of a
214/// linear form.
215///
216class SelectionDAG {
const TargetMachine &TM;
const SelectionDAGTargetInfo *TSI = nullptr;
const TargetLowering *TLI = nullptr;
const TargetLibraryInfo *LibInfo = nullptr;
MachineFunction *MF;
Pass *SDAGISelPass = nullptr;
LLVMContext *Context;
CodeGenOpt::Level OptLevel;

LegacyDivergenceAnalysis * DA = nullptr;
FunctionLoweringInfo * FLI = nullptr;

/// The function-level optimization remark emitter.  Used to emit remarks
/// whenever manipulating the DAG.
OptimizationRemarkEmitter *ORE;

ProfileSummaryInfo *PSI = nullptr;
BlockFrequencyInfo *BFI = nullptr;

/// The starting token.
SDNode EntryNode;

/// The root of the entire DAG.
SDValue Root;

/// A linked list of nodes in the current DAG.
ilist<SDNode> AllNodes;

/// The AllocatorType for allocating SDNodes. We use
/// pool allocation with recycling.
using NodeAllocatorType = RecyclingAllocator<BumpPtrAllocator, SDNode,
                                             sizeof(LargestSDNode),
                                             alignof(MostAlignedSDNode)>;

/// Pool allocation for nodes.
NodeAllocatorType NodeAllocator;

/// This structure is used to memoize nodes, automatically performing
/// CSE with existing nodes when a duplicate is requested.
FoldingSet<SDNode> CSEMap;

/// Pool allocation for machine-opcode SDNode operands.
BumpPtrAllocator OperandAllocator;
ArrayRecycler<SDUse> OperandRecycler;

/// Pool allocation for misc. objects that are created once per SelectionDAG.
BumpPtrAllocator Allocator;

/// Tracks dbg_value and dbg_label information through SDISel.
SDDbgInfo *DbgInfo;

using CallSiteInfo = MachineFunction::CallSiteInfo;
using CallSiteInfoImpl = MachineFunction::CallSiteInfoImpl;

struct CallSiteDbgInfo {
  CallSiteInfo CSInfo;
  MDNode *HeapAllocSite = nullptr;
  bool NoMerge = false;
};

DenseMap<const SDNode *, CallSiteDbgInfo> SDCallSiteDbgInfo;

uint16_t NextPersistentId = 0;

281public:
/// Clients of various APIs that cause global effects on
/// the DAG can optionally implement this interface.  This allows the clients
/// to handle the various sorts of updates that happen.
///
/// A DAGUpdateListener automatically registers itself with DAG when it is
/// constructed, and removes itself when destroyed in RAII fashion.
struct DAGUpdateListener {
  DAGUpdateListener *const Next;
  SelectionDAG &DAG;

  explicit DAGUpdateListener(SelectionDAG &D)
    : Next(D.UpdateListeners), DAG(D) {
    DAG.UpdateListeners = this;
  }

  virtual ~DAGUpdateListener() {
    assert(DAG.UpdateListeners == this &&((void)0)
           "DAGUpdateListeners must be destroyed in LIFO order")((void)0);
    DAG.UpdateListeners = Next;
  }

  /// The node N that was deleted and, if E is not null, an
  /// equivalent node E that replaced it.
  virtual void NodeDeleted(SDNode *N, SDNode *E);

  /// The node N that was updated.
  virtual void NodeUpdated(SDNode *N);

  /// The node N that was inserted.
  virtual void NodeInserted(SDNode *N);
};

struct DAGNodeDeletedListener : public DAGUpdateListener {
  std::function<void(SDNode *, SDNode *)> Callback;

  DAGNodeDeletedListener(SelectionDAG &DAG,
                         std::function<void(SDNode *, SDNode *)> Callback)
      : DAGUpdateListener(DAG), Callback(std::move(Callback)) {}

  void NodeDeleted(SDNode *N, SDNode *E) override { Callback(N, E); }

 private:
  virtual void anchor();
};

/// Help to insert SDNodeFlags automatically in transforming. Use
/// RAII to save and resume flags in current scope.
class FlagInserter {
  SelectionDAG &DAG;
  SDNodeFlags Flags;
  FlagInserter *LastInserter;

public:
  FlagInserter(SelectionDAG &SDAG, SDNodeFlags Flags)
      : DAG(SDAG), Flags(Flags),
        LastInserter(SDAG.getFlagInserter()) {
    SDAG.setFlagInserter(this);
  }
  FlagInserter(SelectionDAG &SDAG, SDNode *N)
      : FlagInserter(SDAG, N->getFlags()) {}

  FlagInserter(const FlagInserter &) = delete;
  FlagInserter &operator=(const FlagInserter &) = delete;
  ~FlagInserter() { DAG.setFlagInserter(LastInserter); }

  SDNodeFlags getFlags() const { return Flags; }
};

/// When true, additional steps are taken to
/// ensure that getConstant() and similar functions return DAG nodes that
/// have legal types. This is important after type legalization since
/// any illegally typed nodes generated after this point will not experience
/// type legalization.
bool NewNodesMustHaveLegalTypes = false;

357private:
/// DAGUpdateListener is a friend so it can manipulate the listener stack.
friend struct DAGUpdateListener;

/// Linked list of registered DAGUpdateListener instances.
/// This stack is maintained by DAGUpdateListener RAII.
DAGUpdateListener *UpdateListeners = nullptr;

/// Implementation of setSubgraphColor.
/// Return whether we had to truncate the search.
bool setSubgraphColorHelper(SDNode *N, const char *Color,
                            DenseSet<SDNode *> &visited,
                            int level, bool &printed);

template <typename SDNodeT, typename... ArgTypes>
SDNodeT *newSDNode(ArgTypes &&... Args) {
  return new (NodeAllocator.template Allocate<SDNodeT>())
      SDNodeT(std::forward<ArgTypes>(Args)...);
}

/// Build a synthetic SDNodeT with the given args and extract its subclass
/// data as an integer (e.g. for use in a folding set).
///
/// The args to this function are the same as the args to SDNodeT's
/// constructor, except the second arg (assumed to be a const DebugLoc&) is
/// omitted.
template <typename SDNodeT, typename... ArgTypes>
static uint16_t getSyntheticNodeSubclassData(unsigned IROrder,
                                             ArgTypes &&... Args) {
  // The compiler can reduce this expression to a constant iff we pass an
  // empty DebugLoc.  Thankfully, the debug location doesn't have any bearing
  // on the subclass data.
  return SDNodeT(IROrder, DebugLoc(), std::forward<ArgTypes>(Args)...)
      .getRawSubclassData();
}

template <typename SDNodeTy>
static uint16_t getSyntheticNodeSubclassData(unsigned Opc, unsigned Order,
                                              SDVTList VTs, EVT MemoryVT,
                                              MachineMemOperand *MMO) {
  return SDNodeTy(Opc, Order, DebugLoc(), VTs, MemoryVT, MMO)
       .getRawSubclassData();
}

void createOperands(SDNode *Node, ArrayRef<SDValue> Vals);

void removeOperands(SDNode *Node) {
  if (!Node->OperandList)
    return;
  OperandRecycler.deallocate(
      ArrayRecycler<SDUse>::Capacity::get(Node->NumOperands),
      Node->OperandList);
  Node->NumOperands = 0;
  Node->OperandList = nullptr;
}
void CreateTopologicalOrder(std::vector<SDNode*>& Order);

414public:
// Maximum depth for recursive analysis such as computeKnownBits, etc.
static constexpr unsigned MaxRecursionDepth = 6;

explicit SelectionDAG(const TargetMachine &TM, CodeGenOpt::Level);
SelectionDAG(const SelectionDAG &) = delete;
SelectionDAG &operator=(const SelectionDAG &) = delete;
~SelectionDAG();

/// Prepare this SelectionDAG to process code in the given MachineFunction.
void init(MachineFunction &NewMF, OptimizationRemarkEmitter &NewORE,
          Pass *PassPtr, const TargetLibraryInfo *LibraryInfo,
          LegacyDivergenceAnalysis * Divergence,
          ProfileSummaryInfo *PSIin, BlockFrequencyInfo *BFIin);

void setFunctionLoweringInfo(FunctionLoweringInfo * FuncInfo) {
  FLI = FuncInfo;
}

/// Clear state and free memory necessary to make this
/// SelectionDAG ready to process a new block.
void clear();

MachineFunction &getMachineFunction() const { return *MF; }
const Pass *getPass() const { return SDAGISelPass; }

const DataLayout &getDataLayout() const { return MF->getDataLayout(); }
const TargetMachine &getTarget() const { return TM; }
const TargetSubtargetInfo &getSubtarget() const { return MF->getSubtarget(); }
const TargetLowering &getTargetLoweringInfo() const { return *TLI; }
const TargetLibraryInfo &getLibInfo() const { return *LibInfo; }
const SelectionDAGTargetInfo &getSelectionDAGInfo() const { return *TSI; }
const LegacyDivergenceAnalysis *getDivergenceAnalysis() const { return DA; }
LLVMContext *getContext() const { return Context; }
OptimizationRemarkEmitter &getORE() const { return *ORE; }
ProfileSummaryInfo *getPSI() const { return PSI; }
BlockFrequencyInfo *getBFI() const { return BFI; }

FlagInserter *getFlagInserter() { return Inserter; }
void setFlagInserter(FlagInserter *FI) { Inserter = FI; }

/// Just dump dot graph to a user-provided path and title.
/// This doesn't open the dot viewer program and
/// helps visualization when outside debugging session.
/// FileName expects absolute path. If provided
/// without any path separators then the file
/// will be created in the current directory.
/// Error will be emitted if the path is insane.
462#if !defined(NDEBUG1) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD__attribute__((noinline)) void dumpDotGraph(const Twine &FileName, const Twine &Title);
464#endif

/// Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
void viewGraph(const std::string &Title);
void viewGraph();

470#ifndef NDEBUG1
std::map<const SDNode *, std::string> NodeGraphAttrs;
472#endif

/// Clear all previously defined node graph attributes.
/// Intended to be used from a debugging tool (eg. gdb).
void clearGraphAttrs();

/// Set graph attributes for a node. (eg. "color=red".)
void setGraphAttrs(const SDNode *N, const char *Attrs);

/// Get graph attributes for a node. (eg. "color=red".)
/// Used from getNodeAttributes.
std::string getGraphAttrs(const SDNode *N) const;

/// Convenience for setting node color attribute.
void setGraphColor(const SDNode *N, const char *Color);

/// Convenience for setting subgraph color attribute.
void setSubgraphColor(SDNode *N, const char *Color);

using allnodes_const_iterator = ilist<SDNode>::const_iterator;

allnodes_const_iterator allnodes_begin() const { return AllNodes.begin(); }
allnodes_const_iterator allnodes_end() const { return AllNodes.end(); }

using allnodes_iterator = ilist<SDNode>::iterator;

allnodes_iterator allnodes_begin() { return AllNodes.begin(); }
allnodes_iterator allnodes_end() { return AllNodes.end(); }

ilist<SDNode>::size_type allnodes_size() const {
  return AllNodes.size();
}

iterator_range<allnodes_iterator> allnodes() {
  return make_range(allnodes_begin(), allnodes_end());
}
iterator_range<allnodes_const_iterator> allnodes() const {
  return make_range(allnodes_begin(), allnodes_end());
}

/// Return the root tag of the SelectionDAG.
const SDValue &getRoot() const { return Root; }

/// Return the token chain corresponding to the entry of the function.
SDValue getEntryNode() const {
  return SDValue(const_cast<SDNode *>(&EntryNode), 0);
}

/// Set the current root tag of the SelectionDAG.
///
const SDValue &setRoot(SDValue N) {
  assert((!N.getNode() || N.getValueType() == MVT::Other) &&((void)0)
         "DAG root value is not a chain!")((void)0);
  if (N.getNode())
    checkForCycles(N.getNode(), this);
  Root = N;
  if (N.getNode())
    checkForCycles(this);
  return Root;
}

533#ifndef NDEBUG1
void VerifyDAGDiverence();
535#endif

/// This iterates over the nodes in the SelectionDAG, folding
/// certain types of nodes together, or eliminating superfluous nodes.  The
/// Level argument controls whether Combine is allowed to produce nodes and
/// types that are illegal on the target.
void Combine(CombineLevel Level, AAResults *AA,
             CodeGenOpt::Level OptLevel);

/// This transforms the SelectionDAG into a SelectionDAG that
/// only uses types natively supported by the target.
/// Returns "true" if it made any changes.
///
/// Note that this is an involved process that may invalidate pointers into
/// the graph.
bool LegalizeTypes();

/// This transforms the SelectionDAG into a SelectionDAG that is
/// compatible with the target instruction selector, as indicated by the
/// TargetLowering object.
///
/// Note that this is an involved process that may invalidate pointers into
/// the graph.
void Legalize();

/// Transforms a SelectionDAG node and any operands to it into a node
/// that is compatible with the target instruction selector, as indicated by
/// the TargetLowering object.
///
/// \returns true if \c N is a valid, legal node after calling this.
///
/// This essentially runs a single recursive walk of the \c Legalize process
/// over the given node (and its operands). This can be used to incrementally
/// legalize the DAG. All of the nodes which are directly replaced,
/// potentially including N, are added to the output parameter \c
/// UpdatedNodes so that the delta to the DAG can be understood by the
/// caller.
///
/// When this returns false, N has been legalized in a way that make the
/// pointer passed in no longer valid. It may have even been deleted from the
/// DAG, and so it shouldn't be used further. When this returns true, the
/// N passed in is a legal node, and can be immediately processed as such.
/// This may still have done some work on the DAG, and will still populate
/// UpdatedNodes with any new nodes replacing those originally in the DAG.
bool LegalizeOp(SDNode *N, SmallSetVector<SDNode *, 16> &UpdatedNodes);

/// This transforms the SelectionDAG into a SelectionDAG
/// that only uses vector math operations supported by the target.  This is
/// necessary as a separate step from Legalize because unrolling a vector
/// operation can introduce illegal types, which requires running
/// LegalizeTypes again.
///
/// This returns true if it made any changes; in that case, LegalizeTypes
/// is called again before Legalize.
///
/// Note that this is an involved process that may invalidate pointers into
/// the graph.
bool LegalizeVectors();

/// This method deletes all unreachable nodes in the SelectionDAG.
void RemoveDeadNodes();

/// Remove the specified node from the system.  This node must
/// have no referrers.
void DeleteNode(SDNode *N);

/// Return an SDVTList that represents the list of values specified.
SDVTList getVTList(EVT VT);
SDVTList getVTList(EVT VT1, EVT VT2);
SDVTList getVTList(EVT VT1, EVT VT2, EVT VT3);
SDVTList getVTList(EVT VT1, EVT VT2, EVT VT3, EVT VT4);
SDVTList getVTList(ArrayRef<EVT> VTs);

//===--------------------------------------------------------------------===//
// Node creation methods.

/// Create a ConstantSDNode wrapping a constant value.
/// If VT is a vector type, the constant is splatted into a BUILD_VECTOR.
///
/// If only legal types can be produced, this does the necessary
/// transformations (e.g., if the vector element type is illegal).
/// @{
SDValue getConstant(uint64_t Val, const SDLoc &DL, EVT VT,
                    bool isTarget = false, bool isOpaque = false);
SDValue getConstant(const APInt &Val, const SDLoc &DL, EVT VT,
                    bool isTarget = false, bool isOpaque = false);

SDValue getAllOnesConstant(const SDLoc &DL, EVT VT, bool IsTarget = false,
                           bool IsOpaque = false) {
  return getConstant(APInt::getAllOnesValue(VT.getScalarSizeInBits()), DL,
                     VT, IsTarget, IsOpaque);
}

SDValue getConstant(const ConstantInt &Val, const SDLoc &DL, EVT VT,
                    bool isTarget = false, bool isOpaque = false);
SDValue getIntPtrConstant(uint64_t Val, const SDLoc &DL,
                          bool isTarget = false);
SDValue getShiftAmountConstant(uint64_t Val, EVT VT, const SDLoc &DL,
                               bool LegalTypes = true);
SDValue getVectorIdxConstant(uint64_t Val, const SDLoc &DL,
                             bool isTarget = false);

SDValue getTargetConstant(uint64_t Val, const SDLoc &DL, EVT VT,
                          bool isOpaque = false) {
  return getConstant(Val, DL, VT, true, isOpaque);
}
SDValue getTargetConstant(const APInt &Val, const SDLoc &DL, EVT VT,
                          bool isOpaque = false) {
  return getConstant(Val, DL, VT, true, isOpaque);
}
SDValue getTargetConstant(const ConstantInt &Val, const SDLoc &DL, EVT VT,
                          bool isOpaque = false) {
  return getConstant(Val, DL, VT, true, isOpaque);
}

/// Create a true or false constant of type \p VT using the target's
/// BooleanContent for type \p OpVT.
SDValue getBoolConstant(bool V, const SDLoc &DL, EVT VT, EVT OpVT);
/// @}

/// Create a ConstantFPSDNode wrapping a constant value.
/// If VT is a vector type, the constant is splatted into a BUILD_VECTOR.
///
/// If only legal types can be produced, this does the necessary
/// transformations (e.g., if the vector element type is illegal).
/// The forms that take a double should only be used for simple constants
/// that can be exactly represented in VT.  No checks are made.
/// @{
SDValue getConstantFP(double Val, const SDLoc &DL, EVT VT,
                      bool isTarget = false);
SDValue getConstantFP(const APFloat &Val, const SDLoc &DL, EVT VT,
                      bool isTarget = false);
SDValue getConstantFP(const ConstantFP &V, const SDLoc &DL, EVT VT,
                      bool isTarget = false);
SDValue getTargetConstantFP(double Val, const SDLoc &DL, EVT VT) {
  return getConstantFP(Val, DL, VT, true);
}
SDValue getTargetConstantFP(const APFloat &Val, const SDLoc &DL, EVT VT) {
  return getConstantFP(Val, DL, VT, true);
}
SDValue getTargetConstantFP(const ConstantFP &Val, const SDLoc &DL, EVT VT) {
  return getConstantFP(Val, DL, VT, true);
}
/// @}

SDValue getGlobalAddress(const GlobalValue *GV, const SDLoc &DL, EVT VT,
                         int64_t offset = 0, bool isTargetGA = false,
                         unsigned TargetFlags = 0);
SDValue getTargetGlobalAddress(const GlobalValue *GV, const SDLoc &DL, EVT VT,
                               int64_t offset = 0, unsigned TargetFlags = 0) {
  return getGlobalAddress(GV, DL, VT, offset, true, TargetFlags);
}
SDValue getFrameIndex(int FI, EVT VT, bool isTarget = false);
SDValue getTargetFrameIndex(int FI, EVT VT) {
  return getFrameIndex(FI, VT, true);
}
SDValue getJumpTable(int JTI, EVT VT, bool isTarget = false,
                     unsigned TargetFlags = 0);
SDValue getTargetJumpTable(int JTI, EVT VT, unsigned TargetFlags = 0) {
  return getJumpTable(JTI, VT, true, TargetFlags);
}
SDValue getConstantPool(const Constant *C, EVT VT, MaybeAlign Align = None,
                        int Offs = 0, bool isT = false,
                        unsigned TargetFlags = 0);
SDValue getTargetConstantPool(const Constant *C, EVT VT,
                              MaybeAlign Align = None, int Offset = 0,
                              unsigned TargetFlags = 0) {
  return getConstantPool(C, VT, Align, Offset, true, TargetFlags);
}
SDValue getConstantPool(MachineConstantPoolValue *C, EVT VT,
                        MaybeAlign Align = None, int Offs = 0,
                        bool isT = false, unsigned TargetFlags = 0);
SDValue getTargetConstantPool(MachineConstantPoolValue *C, EVT VT,
                              MaybeAlign Align = None, int Offset = 0,
                              unsigned TargetFlags = 0) {
  return getConstantPool(C, VT, Align, Offset, true, TargetFlags);
}
SDValue getTargetIndex(int Index, EVT VT, int64_t Offset = 0,
                       unsigned TargetFlags = 0);
// When generating a branch to a BB, we don't in general know enough
// to provide debug info for the BB at that time, so keep this one around.
SDValue getBasicBlock(MachineBasicBlock *MBB);
SDValue getExternalSymbol(const char *Sym, EVT VT);
SDValue getTargetExternalSymbol(const char *Sym, EVT VT,
                                unsigned TargetFlags = 0);
SDValue getMCSymbol(MCSymbol *Sym, EVT VT);

SDValue getValueType(EVT);
SDValue getRegister(unsigned Reg, EVT VT);
SDValue getRegisterMask(const uint32_t *RegMask);
SDValue getEHLabel(const SDLoc &dl, SDValue Root, MCSymbol *Label);
SDValue getLabelNode(unsigned Opcode, const SDLoc &dl, SDValue Root,
                     MCSymbol *Label);
SDValue getBlockAddress(const BlockAddress *BA, EVT VT, int64_t Offset = 0,
                        bool isTarget = false, unsigned TargetFlags = 0);
SDValue getTargetBlockAddress(const BlockAddress *BA, EVT VT,
                              int64_t Offset = 0, unsigned TargetFlags = 0) {
  return getBlockAddress(BA, VT, Offset, true, TargetFlags);
}

SDValue getCopyToReg(SDValue Chain, const SDLoc &dl, unsigned Reg,
                     SDValue N) {
  return getNode(ISD::CopyToReg, dl, MVT::Other, Chain,
                 getRegister(Reg, N.getValueType()), N);
}

// This version of the getCopyToReg method takes an extra operand, which
// indicates that there is potentially an incoming glue value (if Glue is not
// null) and that there should be a glue result.
SDValue getCopyToReg(SDValue Chain, const SDLoc &dl, unsigned Reg, SDValue N,
                     SDValue Glue) {
  SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
  SDValue Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Glue };
10
←
Calling 'SDValue::getValueType'→
  return getNode(ISD::CopyToReg, dl, VTs,
                 makeArrayRef(Ops, Glue.getNode() ? 4 : 3));
}

// Similar to last getCopyToReg() except parameter Reg is a SDValue
SDValue getCopyToReg(SDValue Chain, const SDLoc &dl, SDValue Reg, SDValue N,
                     SDValue Glue) {
  SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
  SDValue Ops[] = { Chain, Reg, N, Glue };
  return getNode(ISD::CopyToReg, dl, VTs,
                 makeArrayRef(Ops, Glue.getNode() ? 4 : 3));
}

SDValue getCopyFromReg(SDValue Chain, const SDLoc &dl, unsigned Reg, EVT VT) {
  SDVTList VTs = getVTList(VT, MVT::Other);
  SDValue Ops[] = { Chain, getRegister(Reg, VT) };
  return getNode(ISD::CopyFromReg, dl, VTs, Ops);
}

// This version of the getCopyFromReg method takes an extra operand, which
// indicates that there is potentially an incoming glue value (if Glue is not
// null) and that there should be a glue result.
SDValue getCopyFromReg(SDValue Chain, const SDLoc &dl, unsigned Reg, EVT VT,
                       SDValue Glue) {
  SDVTList VTs = getVTList(VT, MVT::Other, MVT::Glue);
  SDValue Ops[] = { Chain, getRegister(Reg, VT), Glue };
  return getNode(ISD::CopyFromReg, dl, VTs,
                 makeArrayRef(Ops, Glue.getNode() ? 3 : 2));
}

SDValue getCondCode(ISD::CondCode Cond);

/// Return an ISD::VECTOR_SHUFFLE node. The number of elements in VT,
/// which must be a vector type, must match the number of mask elements
/// NumElts. An integer mask element equal to -1 is treated as undefined.
SDValue getVectorShuffle(EVT VT, const SDLoc &dl, SDValue N1, SDValue N2,
                         ArrayRef<int> Mask);

/// Return an ISD::BUILD_VECTOR node. The number of elements in VT,
/// which must be a vector type, must match the number of operands in Ops.
/// The operands must have the same type as (or, for integers, a type wider
/// than) VT's element type.
SDValue getBuildVector(EVT VT, const SDLoc &DL, ArrayRef<SDValue> Ops) {
  // VerifySDNode (via InsertNode) checks BUILD_VECTOR later.
  return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
}

/// Return an ISD::BUILD_VECTOR node. The number of elements in VT,
/// which must be a vector type, must match the number of operands in Ops.
/// The operands must have the same type as (or, for integers, a type wider
/// than) VT's element type.
SDValue getBuildVector(EVT VT, const SDLoc &DL, ArrayRef<SDUse> Ops) {
  // VerifySDNode (via InsertNode) checks BUILD_VECTOR later.
  return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
}

/// Return a splat ISD::BUILD_VECTOR node, consisting of Op splatted to all
/// elements. VT must be a vector type. Op's type must be the same as (or,
/// for integers, a type wider than) VT's element type.
SDValue getSplatBuildVector(EVT VT, const SDLoc &DL, SDValue Op) {
  // VerifySDNode (via InsertNode) checks BUILD_VECTOR later.
  if (Op.getOpcode() == ISD::UNDEF) {
    assert((VT.getVectorElementType() == Op.getValueType() ||((void)0)
            (VT.isInteger() &&((void)0)
             VT.getVectorElementType().bitsLE(Op.getValueType()))) &&((void)0)
           "A splatted value must have a width equal or (for integers) "((void)0)
           "greater than the vector element type!")((void)0);
    return getNode(ISD::UNDEF, SDLoc(), VT);
  }

  SmallVector<SDValue, 16> Ops(VT.getVectorNumElements(), Op);
  return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
}

// Return a splat ISD::SPLAT_VECTOR node, consisting of Op splatted to all
// elements.
SDValue getSplatVector(EVT VT, const SDLoc &DL, SDValue Op) {
  if (Op.getOpcode() == ISD::UNDEF) {
    assert((VT.getVectorElementType() == Op.getValueType() ||((void)0)
            (VT.isInteger() &&((void)0)
             VT.getVectorElementType().bitsLE(Op.getValueType()))) &&((void)0)
           "A splatted value must have a width equal or (for integers) "((void)0)
           "greater than the vector element type!")((void)0);
    return getNode(ISD::UNDEF, SDLoc(), VT);
  }
  return getNode(ISD::SPLAT_VECTOR, DL, VT, Op);
}

/// Returns a vector of type ResVT whose elements contain the linear sequence
///   <0, Step, Step * 2, Step * 3, ...>
SDValue getStepVector(const SDLoc &DL, EVT ResVT, APInt StepVal);

/// Returns a vector of type ResVT whose elements contain the linear sequence
///   <0, 1, 2, 3, ...>
SDValue getStepVector(const SDLoc &DL, EVT ResVT);

/// Returns an ISD::VECTOR_SHUFFLE node semantically equivalent to
/// the shuffle node in input but with swapped operands.
///
/// Example: shuffle A, B, <0,5,2,7> -> shuffle B, A, <4,1,6,3>
SDValue getCommutedVectorShuffle(const ShuffleVectorSDNode &SV);

/// Convert Op, which must be of float type, to the
/// float type VT, by either extending or rounding (by truncation).
SDValue getFPExtendOrRound(SDValue Op, const SDLoc &DL, EVT VT);

/// Convert Op, which must be a STRICT operation of float type, to the
/// float type VT, by either extending or rounding (by truncation).
std::pair<SDValue, SDValue>
getStrictFPExtendOrRound(SDValue Op, SDValue Chain, const SDLoc &DL, EVT VT);

/// Convert Op, which must be of integer type, to the
/// integer type VT, by either any-extending or truncating it.
SDValue getAnyExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);

/// Convert Op, which must be of integer type, to the
/// integer type VT, by either sign-extending or truncating it.
SDValue getSExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);

/// Convert Op, which must be of integer type, to the
/// integer type VT, by either zero-extending or truncating it.
SDValue getZExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);

/// Return the expression required to zero extend the Op
/// value assuming it was the smaller SrcTy value.
SDValue getZeroExtendInReg(SDValue Op, const SDLoc &DL, EVT VT);

/// Convert Op, which must be of integer type, to the integer type VT, by
/// either truncating it or performing either zero or sign extension as
/// appropriate extension for the pointer's semantics.
SDValue getPtrExtOrTrunc(SDValue Op, const SDLoc &DL, EVT VT);

/// Return the expression required to extend the Op as a pointer value
/// assuming it was the smaller SrcTy value. This may be either a zero extend
/// or a sign extend.
SDValue getPtrExtendInReg(SDValue Op, const SDLoc &DL, EVT VT);

/// Convert Op, which must be of integer type, to the integer type VT,
/// by using an extension appropriate for the target's
/// BooleanContent for type OpVT or truncating it.
SDValue getBoolExtOrTrunc(SDValue Op, const SDLoc &SL, EVT VT, EVT OpVT);

/// Create a bitwise NOT operation as (XOR Val, -1).
SDValue getNOT(const SDLoc &DL, SDValue Val, EVT VT);

/// Create a logical NOT operation as (XOR Val, BooleanOne).
SDValue getLogicalNOT(const SDLoc &DL, SDValue Val, EVT VT);

/// Returns sum of the base pointer and offset.
/// Unlike getObjectPtrOffset this does not set NoUnsignedWrap by default.
SDValue getMemBasePlusOffset(SDValue Base, TypeSize Offset, const SDLoc &DL,
                             const SDNodeFlags Flags = SDNodeFlags());
SDValue getMemBasePlusOffset(SDValue Base, SDValue Offset, const SDLoc &DL,
                             const SDNodeFlags Flags = SDNodeFlags());

/// Create an add instruction with appropriate flags when used for
/// addressing some offset of an object. i.e. if a load is split into multiple
/// components, create an add nuw from the base pointer to the offset.
SDValue getObjectPtrOffset(const SDLoc &SL, SDValue Ptr, TypeSize Offset) {
  SDNodeFlags Flags;
  Flags.setNoUnsignedWrap(true);
  return getMemBasePlusOffset(Ptr, Offset, SL, Flags);
}

SDValue getObjectPtrOffset(const SDLoc &SL, SDValue Ptr, SDValue Offset) {
  // The object itself can't wrap around the address space, so it shouldn't be
  // possible for the adds of the offsets to the split parts to overflow.
  SDNodeFlags Flags;
  Flags.setNoUnsignedWrap(true);
  return getMemBasePlusOffset(Ptr, Offset, SL, Flags);
}

/// Return a new CALLSEQ_START node, that starts new call frame, in which
/// InSize bytes are set up inside CALLSEQ_START..CALLSEQ_END sequence and
/// OutSize specifies part of the frame set up prior to the sequence.
SDValue getCALLSEQ_START(SDValue Chain, uint64_t InSize, uint64_t OutSize,
                         const SDLoc &DL) {
  SDVTList VTs = getVTList(MVT::Other, MVT::Glue);
  SDValue Ops[] = { Chain,
                    getIntPtrConstant(InSize, DL, true),
                    getIntPtrConstant(OutSize, DL, true) };
  return getNode(ISD::CALLSEQ_START, DL, VTs, Ops);
}

/// Return a new CALLSEQ_END node, which always must have a
/// glue result (to ensure it's not CSE'd).
/// CALLSEQ_END does not have a useful SDLoc.
SDValue getCALLSEQ_END(SDValue Chain, SDValue Op1, SDValue Op2,
                       SDValue InGlue, const SDLoc &DL) {
  SDVTList NodeTys = getVTList(MVT::Other, MVT::Glue);
  SmallVector<SDValue, 4> Ops;
  Ops.push_back(Chain);
  Ops.push_back(Op1);
  Ops.push_back(Op2);
  if (InGlue.getNode())
    Ops.push_back(InGlue);
  return getNode(ISD::CALLSEQ_END, DL, NodeTys, Ops);
}

/// Return true if the result of this operation is always undefined.
bool isUndef(unsigned Opcode, ArrayRef<SDValue> Ops);

/// Return an UNDEF node. UNDEF does not have a useful SDLoc.
SDValue getUNDEF(EVT VT) {
  return getNode(ISD::UNDEF, SDLoc(), VT);
}

/// Return a node that represents the runtime scaling 'MulImm * RuntimeVL'.
SDValue getVScale(const SDLoc &DL, EVT VT, APInt MulImm) {
  assert(MulImm.getMinSignedBits() <= VT.getSizeInBits() &&((void)0)
         "Immediate does not fit VT")((void)0);
  return getNode(ISD::VSCALE, DL, VT,
                 getConstant(MulImm.sextOrTrunc(VT.getSizeInBits()), DL, VT));
}

/// Return a GLOBAL_OFFSET_TABLE node. This does not have a useful SDLoc.
SDValue getGLOBAL_OFFSET_TABLE(EVT VT) {
  return getNode(ISD::GLOBAL_OFFSET_TABLE, SDLoc(), VT);
}

/// Gets or creates the specified node.
///
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                ArrayRef<SDUse> Ops);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                ArrayRef<SDValue> Ops, const SDNodeFlags Flags);
SDValue getNode(unsigned Opcode, const SDLoc &DL, ArrayRef<EVT> ResultTys,
                ArrayRef<SDValue> Ops);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                ArrayRef<SDValue> Ops, const SDNodeFlags Flags);

// Use flags from current flag inserter.
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
                ArrayRef<SDValue> Ops);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
                ArrayRef<SDValue> Ops);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue Operand);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                SDValue N2);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                SDValue N2, SDValue N3);

// Specialize based on number of operands.
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue Operand,
                const SDNodeFlags Flags);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                SDValue N2, const SDNodeFlags Flags);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                SDValue N2, SDValue N3, const SDNodeFlags Flags);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                SDValue N2, SDValue N3, SDValue N4);
SDValue getNode(unsigned Opcode, const SDLoc &DL, EVT VT, SDValue N1,
                SDValue N2, SDValue N3, SDValue N4, SDValue N5);

// Specialize again based on number of operands for nodes with a VTList
// rather than a single VT.
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList, SDValue N);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList, SDValue N1,
                SDValue N2);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList, SDValue N1,
                SDValue N2, SDValue N3);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList, SDValue N1,
                SDValue N2, SDValue N3, SDValue N4);
SDValue getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList, SDValue N1,
                SDValue N2, SDValue N3, SDValue N4, SDValue N5);

/// Compute a TokenFactor to force all the incoming stack arguments to be
/// loaded from the stack. This is used in tail call lowering to protect
/// stack arguments from being clobbered.
SDValue getStackArgumentTokenFactor(SDValue Chain);

SDValue getMemcpy(SDValue Chain, const SDLoc &dl, SDValue Dst, SDValue Src,
                  SDValue Size, Align Alignment, bool isVol,
                  bool AlwaysInline, bool isTailCall,
                  MachinePointerInfo DstPtrInfo,
                  MachinePointerInfo SrcPtrInfo,
                  const AAMDNodes &AAInfo = AAMDNodes());

SDValue getMemmove(SDValue Chain, const SDLoc &dl, SDValue Dst, SDValue Src,
                   SDValue Size, Align Alignment, bool isVol, bool isTailCall,
                   MachinePointerInfo DstPtrInfo,
                   MachinePointerInfo SrcPtrInfo,
                   const AAMDNodes &AAInfo = AAMDNodes());

SDValue getMemset(SDValue Chain, const SDLoc &dl, SDValue Dst, SDValue Src,
                  SDValue Size, Align Alignment, bool isVol, bool isTailCall,
                  MachinePointerInfo DstPtrInfo,
                  const AAMDNodes &AAInfo = AAMDNodes());

SDValue getAtomicMemcpy(SDValue Chain, const SDLoc &dl, SDValue Dst,
                        unsigned DstAlign, SDValue Src, unsigned SrcAlign,
                        SDValue Size, Type *SizeTy, unsigned ElemSz,
                        bool isTailCall, MachinePointerInfo DstPtrInfo,
                        MachinePointerInfo SrcPtrInfo);

SDValue getAtomicMemmove(SDValue Chain, const SDLoc &dl, SDValue Dst,
                         unsigned DstAlign, SDValue Src, unsigned SrcAlign,
                         SDValue Size, Type *SizeTy, unsigned ElemSz,
                         bool isTailCall, MachinePointerInfo DstPtrInfo,
                         MachinePointerInfo SrcPtrInfo);

SDValue getAtomicMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
                        unsigned DstAlign, SDValue Value, SDValue Size,
                        Type *SizeTy, unsigned ElemSz, bool isTailCall,
                        MachinePointerInfo DstPtrInfo);

/// Helper function to make it easier to build SetCC's if you just have an
/// ISD::CondCode instead of an SDValue.
SDValue getSetCC(const SDLoc &DL, EVT VT, SDValue LHS, SDValue RHS,
                 ISD::CondCode Cond, SDValue Chain = SDValue(),
                 bool IsSignaling = false) {
  assert(LHS.getValueType().isVector() == RHS.getValueType().isVector() &&((void)0)
         "Cannot compare scalars to vectors")((void)0);
  assert(LHS.getValueType().isVector() == VT.isVector() &&((void)0)
         "Cannot compare scalars to vectors")((void)0);
  assert(Cond != ISD::SETCC_INVALID &&((void)0)
         "Cannot create a setCC of an invalid node.")((void)0);
  if (Chain)
    return getNode(IsSignaling ? ISD::STRICT_FSETCCS : ISD::STRICT_FSETCC, DL,
                   {VT, MVT::Other}, {Chain, LHS, RHS, getCondCode(Cond)});
  return getNode(ISD::SETCC, DL, VT, LHS, RHS, getCondCode(Cond));
}

/// Helper function to make it easier to build Select's if you just have
/// operands and don't want to check for vector.
SDValue getSelect(const SDLoc &DL, EVT VT, SDValue Cond, SDValue LHS,
                  SDValue RHS) {
  assert(LHS.getValueType() == RHS.getValueType() &&((void)0)
         "Cannot use select on differing types")((void)0);
  assert(VT.isVector() == LHS.getValueType().isVector() &&((void)0)
         "Cannot mix vectors and scalars")((void)0);
  auto Opcode = Cond.getValueType().isVector() ? ISD::VSELECT : ISD::SELECT;
  return getNode(Opcode, DL, VT, Cond, LHS, RHS);
}

/// Helper function to make it easier to build SelectCC's if you just have an
/// ISD::CondCode instead of an SDValue.
SDValue getSelectCC(const SDLoc &DL, SDValue LHS, SDValue RHS, SDValue True,
                    SDValue False, ISD::CondCode Cond) {
  return getNode(ISD::SELECT_CC, DL, True.getValueType(), LHS, RHS, True,
                 False, getCondCode(Cond));
}

/// Try to simplify a select/vselect into 1 of its operands or a constant.
SDValue simplifySelect(SDValue Cond, SDValue TVal, SDValue FVal);

/// Try to simplify a shift into 1 of its operands or a constant.
SDValue simplifyShift(SDValue X, SDValue Y);

/// Try to simplify a floating-point binary operation into 1 of its operands
/// or a constant.
SDValue simplifyFPBinop(unsigned Opcode, SDValue X, SDValue Y,
                        SDNodeFlags Flags);

/// VAArg produces a result and token chain, and takes a pointer
/// and a source value as input.
SDValue getVAArg(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
                 SDValue SV, unsigned Align);

/// Gets a node for an atomic cmpxchg op. There are two
/// valid Opcodes. ISD::ATOMIC_CMO_SWAP produces the value loaded and a
/// chain result. ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS produces the value loaded,
/// a success flag (initially i1), and a chain.
SDValue getAtomicCmpSwap(unsigned Opcode, const SDLoc &dl, EVT MemVT,
                         SDVTList VTs, SDValue Chain, SDValue Ptr,
                         SDValue Cmp, SDValue Swp, MachineMemOperand *MMO);

/// Gets a node for an atomic op, produces result (if relevant)
/// and chain and takes 2 operands.
SDValue getAtomic(unsigned Opcode, const SDLoc &dl, EVT MemVT, SDValue Chain,
                  SDValue Ptr, SDValue Val, MachineMemOperand *MMO);

/// Gets a node for an atomic op, produces result and chain and
/// takes 1 operand.
SDValue getAtomic(unsigned Opcode, const SDLoc &dl, EVT MemVT, EVT VT,
                  SDValue Chain, SDValue Ptr, MachineMemOperand *MMO);

/// Gets a node for an atomic op, produces result and chain and takes N
/// operands.
SDValue getAtomic(unsigned Opcode, const SDLoc &dl, EVT MemVT,
                  SDVTList VTList, ArrayRef<SDValue> Ops,
                  MachineMemOperand *MMO);

/// Creates a MemIntrinsicNode that may produce a
/// result and takes a list of operands. Opcode may be INTRINSIC_VOID,
/// INTRINSIC_W_CHAIN, or a target-specific opcode with a value not
/// less than FIRST_TARGET_MEMORY_OPCODE.
SDValue getMemIntrinsicNode(
    unsigned Opcode, const SDLoc &dl, SDVTList VTList, ArrayRef<SDValue> Ops,
    EVT MemVT, MachinePointerInfo PtrInfo, Align Alignment,
    MachineMemOperand::Flags Flags = MachineMemOperand::MOLoad |
                                     MachineMemOperand::MOStore,
    uint64_t Size = 0, const AAMDNodes &AAInfo = AAMDNodes());

inline SDValue getMemIntrinsicNode(
    unsigned Opcode, const SDLoc &dl, SDVTList VTList, ArrayRef<SDValue> Ops,
    EVT MemVT, MachinePointerInfo PtrInfo, MaybeAlign Alignment = None,
    MachineMemOperand::Flags Flags = MachineMemOperand::MOLoad |
                                     MachineMemOperand::MOStore,
    uint64_t Size = 0, const AAMDNodes &AAInfo = AAMDNodes()) {
  // Ensure that codegen never sees alignment 0
  return getMemIntrinsicNode(Opcode, dl, VTList, Ops, MemVT, PtrInfo,
                             Alignment.getValueOr(getEVTAlign(MemVT)), Flags,
                             Size, AAInfo);
}

SDValue getMemIntrinsicNode(unsigned Opcode, const SDLoc &dl, SDVTList VTList,
                            ArrayRef<SDValue> Ops, EVT MemVT,
                            MachineMemOperand *MMO);

/// Creates a LifetimeSDNode that starts (`IsStart==true`) or ends
/// (`IsStart==false`) the lifetime of the portion of `FrameIndex` between
/// offsets `Offset` and `Offset + Size`.
SDValue getLifetimeNode(bool IsStart, const SDLoc &dl, SDValue Chain,
                        int FrameIndex, int64_t Size, int64_t Offset = -1);

/// Creates a PseudoProbeSDNode with function GUID `Guid` and
/// the index of the block `Index` it is probing, as well as the attributes
/// `attr` of the probe.
SDValue getPseudoProbeNode(const SDLoc &Dl, SDValue Chain, uint64_t Guid,
                           uint64_t Index, uint32_t Attr);

/// Create a MERGE_VALUES node from the given operands.
SDValue getMergeValues(ArrayRef<SDValue> Ops, const SDLoc &dl);

/// Loads are not normal binary operators: their result type is not
/// determined by their operands, and they produce a value AND a token chain.
///
/// This function will set the MOLoad flag on MMOFlags, but you can set it if
/// you want.  The MOStore flag must not be set.
SDValue getLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
                MachinePointerInfo PtrInfo,
                MaybeAlign Alignment = MaybeAlign(),
                MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
                const AAMDNodes &AAInfo = AAMDNodes(),
                const MDNode *Ranges = nullptr);
/// FIXME: Remove once transition to Align is over.
inline SDValue
getLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
        MachinePointerInfo PtrInfo, unsigned Alignment,
        MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
        const AAMDNodes &AAInfo = AAMDNodes(),
        const MDNode *Ranges = nullptr) {
  return getLoad(VT, dl, Chain, Ptr, PtrInfo, MaybeAlign(Alignment), MMOFlags,
                 AAInfo, Ranges);
}
SDValue getLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Ptr,
                MachineMemOperand *MMO);
SDValue
getExtLoad(ISD::LoadExtType ExtType, const SDLoc &dl, EVT VT, SDValue Chain,
           SDValue Ptr, MachinePointerInfo PtrInfo, EVT MemVT,
           MaybeAlign Alignment = MaybeAlign(),
           MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
           const AAMDNodes &AAInfo = AAMDNodes());
/// FIXME: Remove once transition to Align is over.
inline SDValue
getExtLoad(ISD::LoadExtType ExtType, const SDLoc &dl, EVT VT, SDValue Chain,
           SDValue Ptr, MachinePointerInfo PtrInfo, EVT MemVT,
           unsigned Alignment,
           MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
           const AAMDNodes &AAInfo = AAMDNodes()) {
  return getExtLoad(ExtType, dl, VT, Chain, Ptr, PtrInfo, MemVT,
                    MaybeAlign(Alignment), MMOFlags, AAInfo);
}
SDValue getExtLoad(ISD::LoadExtType ExtType, const SDLoc &dl, EVT VT,
                   SDValue Chain, SDValue Ptr, EVT MemVT,
                   MachineMemOperand *MMO);
SDValue getIndexedLoad(SDValue OrigLoad, const SDLoc &dl, SDValue Base,
                       SDValue Offset, ISD::MemIndexedMode AM);
SDValue getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT,
                const SDLoc &dl, SDValue Chain, SDValue Ptr, SDValue Offset,
                MachinePointerInfo PtrInfo, EVT MemVT, Align Alignment,
                MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
                const AAMDNodes &AAInfo = AAMDNodes(),
                const MDNode *Ranges = nullptr);
inline SDValue getLoad(
    ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT, const SDLoc &dl,
    SDValue Chain, SDValue Ptr, SDValue Offset, MachinePointerInfo PtrInfo,
    EVT MemVT, MaybeAlign Alignment = MaybeAlign(),
    MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
    const AAMDNodes &AAInfo = AAMDNodes(), const MDNode *Ranges = nullptr) {
  // Ensures that codegen never sees a None Alignment.
  return getLoad(AM, ExtType, VT, dl, Chain, Ptr, Offset, PtrInfo, MemVT,
                 Alignment.getValueOr(getEVTAlign(MemVT)), MMOFlags, AAInfo,
                 Ranges);
}
/// FIXME: Remove once transition to Align is over.
inline SDValue
getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT,
        const SDLoc &dl, SDValue Chain, SDValue Ptr, SDValue Offset,
        MachinePointerInfo PtrInfo, EVT MemVT, unsigned Alignment,
        MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
        const AAMDNodes &AAInfo = AAMDNodes(),
        const MDNode *Ranges = nullptr) {
  return getLoad(AM, ExtType, VT, dl, Chain, Ptr, Offset, PtrInfo, MemVT,
                 MaybeAlign(Alignment), MMOFlags, AAInfo, Ranges);
}
SDValue getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType, EVT VT,
                const SDLoc &dl, SDValue Chain, SDValue Ptr, SDValue Offset,
                EVT MemVT, MachineMemOperand *MMO);

/// Helper function to build ISD::STORE nodes.
///
/// This function will set the MOStore flag on MMOFlags, but you can set it if
/// you want.  The MOLoad and MOInvariant flags must not be set.

SDValue
getStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
         MachinePointerInfo PtrInfo, Align Alignment,
         MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
         const AAMDNodes &AAInfo = AAMDNodes());
inline SDValue
getStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
         MachinePointerInfo PtrInfo, MaybeAlign Alignment = MaybeAlign(),
         MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
         const AAMDNodes &AAInfo = AAMDNodes()) {
  return getStore(Chain, dl, Val, Ptr, PtrInfo,
                  Alignment.getValueOr(getEVTAlign(Val.getValueType())),
                  MMOFlags, AAInfo);
}
/// FIXME: Remove once transition to Align is over.
inline SDValue
getStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
         MachinePointerInfo PtrInfo, unsigned Alignment,
         MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
         const AAMDNodes &AAInfo = AAMDNodes()) {
  return getStore(Chain, dl, Val, Ptr, PtrInfo, MaybeAlign(Alignment),
                  MMOFlags, AAInfo);
}
SDValue getStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
                 MachineMemOperand *MMO);
SDValue
getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
              MachinePointerInfo PtrInfo, EVT SVT, Align Alignment,
              MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
              const AAMDNodes &AAInfo = AAMDNodes());
inline SDValue
getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
              MachinePointerInfo PtrInfo, EVT SVT,
              MaybeAlign Alignment = MaybeAlign(),
              MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
              const AAMDNodes &AAInfo = AAMDNodes()) {
  return getTruncStore(Chain, dl, Val, Ptr, PtrInfo, SVT,
                       Alignment.getValueOr(getEVTAlign(SVT)), MMOFlags,
                       AAInfo);
}
/// FIXME: Remove once transition to Align is over.
inline SDValue
getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val, SDValue Ptr,
              MachinePointerInfo PtrInfo, EVT SVT, unsigned Alignment,
              MachineMemOperand::Flags MMOFlags = MachineMemOperand::MONone,
              const AAMDNodes &AAInfo = AAMDNodes()) {
  return getTruncStore(Chain, dl, Val, Ptr, PtrInfo, SVT,
                       MaybeAlign(Alignment), MMOFlags, AAInfo);
}
SDValue getTruncStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                      SDValue Ptr, EVT SVT, MachineMemOperand *MMO);
SDValue getIndexedStore(SDValue OrigStore, const SDLoc &dl, SDValue Base,
                        SDValue Offset, ISD::MemIndexedMode AM);

SDValue getMaskedLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Base,
                      SDValue Offset, SDValue Mask, SDValue Src0, EVT MemVT,
                      MachineMemOperand *MMO, ISD::MemIndexedMode AM,
                      ISD::LoadExtType, bool IsExpanding = false);
SDValue getIndexedMaskedLoad(SDValue OrigLoad, const SDLoc &dl, SDValue Base,
                             SDValue Offset, ISD::MemIndexedMode AM);
SDValue getMaskedStore(SDValue Chain, const SDLoc &dl, SDValue Val,
                       SDValue Base, SDValue Offset, SDValue Mask, EVT MemVT,
                       MachineMemOperand *MMO, ISD::MemIndexedMode AM,
                       bool IsTruncating = false, bool IsCompressing = false);
SDValue getIndexedMaskedStore(SDValue OrigStore, const SDLoc &dl,
                              SDValue Base, SDValue Offset,
                              ISD::MemIndexedMode AM);
SDValue getMaskedGather(SDVTList VTs, EVT MemVT, const SDLoc &dl,
                        ArrayRef<SDValue> Ops, MachineMemOperand *MMO,
                        ISD::MemIndexType IndexType, ISD::LoadExtType ExtTy);
SDValue getMaskedScatter(SDVTList VTs, EVT MemVT, const SDLoc &dl,
                         ArrayRef<SDValue> Ops, MachineMemOperand *MMO,
                         ISD::MemIndexType IndexType,
                         bool IsTruncating = false);

/// Construct a node to track a Value* through the backend.
SDValue getSrcValue(const Value *v);

/// Return an MDNodeSDNode which holds an MDNode.
SDValue getMDNode(const MDNode *MD);

/// Return a bitcast using the SDLoc of the value operand, and casting to the
/// provided type. Use getNode to set a custom SDLoc.
SDValue getBitcast(EVT VT, SDValue V);

/// Return an AddrSpaceCastSDNode.
SDValue getAddrSpaceCast(const SDLoc &dl, EVT VT, SDValue Ptr, unsigned SrcAS,
                         unsigned DestAS);

/// Return a freeze using the SDLoc of the value operand.
SDValue getFreeze(SDValue V);

/// Return an AssertAlignSDNode.
SDValue getAssertAlign(const SDLoc &DL, SDValue V, Align A);

/// Return the specified value casted to
/// the target's desired shift amount type.
SDValue getShiftAmountOperand(EVT LHSTy, SDValue Op);

/// Expand the specified \c ISD::VAARG node as the Legalize pass would.
SDValue expandVAArg(SDNode *Node);

/// Expand the specified \c ISD::VACOPY node as the Legalize pass would.
SDValue expandVACopy(SDNode *Node);

/// Returs an GlobalAddress of the function from the current module with
/// name matching the given ExternalSymbol. Additionally can provide the
/// matched function.
/// Panics the function doesn't exists.
SDValue getSymbolFunctionGlobalAddress(SDValue Op,
                                       Function **TargetFunction = nullptr);

/// *Mutate* the specified node in-place to have the
/// specified operands.  If the resultant node already exists in the DAG,
/// this does not modify the specified node, instead it returns the node that
/// already exists.  If the resultant node does not exist in the DAG, the
/// input node is returned.  As a degenerate case, if you specify the same
/// input operands as the node already has, the input node is returned.
SDNode *UpdateNodeOperands(SDNode *N, SDValue Op);
SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2);
SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2,
                             SDValue Op3);
SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2,
                             SDValue Op3, SDValue Op4);
SDNode *UpdateNodeOperands(SDNode *N, SDValue Op1, SDValue Op2,
                             SDValue Op3, SDValue Op4, SDValue Op5);
SDNode *UpdateNodeOperands(SDNode *N, ArrayRef<SDValue> Ops);

/// Creates a new TokenFactor containing \p Vals. If \p Vals contains 64k
/// values or more, move values into new TokenFactors in 64k-1 blocks, until
/// the final TokenFactor has less than 64k operands.
SDValue getTokenFactor(const SDLoc &DL, SmallVectorImpl<SDValue> &Vals);

/// *Mutate* the specified machine node's memory references to the provided
/// list.
void setNodeMemRefs(MachineSDNode *N,
                    ArrayRef<MachineMemOperand *> NewMemRefs);

// Calculate divergence of node \p N based on its operands.
bool calculateDivergence(SDNode *N);

// Propagates the change in divergence to users
void updateDivergence(SDNode * N);

/// These are used for target selectors to *mutate* the
/// specified node to have the specified return type, Target opcode, and
/// operands.  Note that target opcodes are stored as
/// ~TargetOpcode in the node opcode field.  The resultant node is returned.
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT, SDValue Op1);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                     SDValue Op1, SDValue Op2);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                     SDValue Op1, SDValue Op2, SDValue Op3);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT,
                     ArrayRef<SDValue> Ops);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1, EVT VT2);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                     EVT VT2, ArrayRef<SDValue> Ops);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                     EVT VT2, EVT VT3, ArrayRef<SDValue> Ops);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
                     EVT VT2, SDValue Op1, SDValue Op2);
SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, SDVTList VTs,
                     ArrayRef<SDValue> Ops);

/// This *mutates* the specified node to have the specified
/// return type, opcode, and operands.
SDNode *MorphNodeTo(SDNode *N, unsigned Opc, SDVTList VTs,
                    ArrayRef<SDValue> Ops);

/// Mutate the specified strict FP node to its non-strict equivalent,
/// unlinking the node from its chain and dropping the metadata arguments.
/// The node must be a strict FP node.
SDNode *mutateStrictFPToFP(SDNode *Node);

/// These are used for target selectors to create a new node
/// with specified return type(s), MachineInstr opcode, and operands.
///
/// Note that getMachineNode returns the resultant node.  If there is already
/// a node of the specified opcode and operands, it returns that node instead
/// of the current one.
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT,
                              SDValue Op1);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT,
                              SDValue Op1, SDValue Op2);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT,
                              SDValue Op1, SDValue Op2, SDValue Op3);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT,
                              ArrayRef<SDValue> Ops);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT1,
                              EVT VT2, SDValue Op1, SDValue Op2);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT1,
                              EVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT1,
                              EVT VT2, ArrayRef<SDValue> Ops);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT1,
                              EVT VT2, EVT VT3, SDValue Op1, SDValue Op2);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT1,
                              EVT VT2, EVT VT3, SDValue Op1, SDValue Op2,
                              SDValue Op3);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, EVT VT1,
                              EVT VT2, EVT VT3, ArrayRef<SDValue> Ops);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl,
                              ArrayRef<EVT> ResultTys, ArrayRef<SDValue> Ops);
MachineSDNode *getMachineNode(unsigned Opcode, const SDLoc &dl, SDVTList VTs,
                              ArrayRef<SDValue> Ops);

/// A convenience function for creating TargetInstrInfo::EXTRACT_SUBREG nodes.
SDValue getTargetExtractSubreg(int SRIdx, const SDLoc &DL, EVT VT,
                               SDValue Operand);

/// A convenience function for creating TargetInstrInfo::INSERT_SUBREG nodes.
SDValue getTargetInsertSubreg(int SRIdx, const SDLoc &DL, EVT VT,
                              SDValue Operand, SDValue Subreg);

/// Get the specified node if it's already available, or else return NULL.
SDNode *getNodeIfExists(unsigned Opcode, SDVTList VTList,
                        ArrayRef<SDValue> Ops, const SDNodeFlags Flags);
SDNode *getNodeIfExists(unsigned Opcode, SDVTList VTList,
                        ArrayRef<SDValue> Ops);

/// Check if a node exists without modifying its flags.
bool doesNodeExist(unsigned Opcode, SDVTList VTList, ArrayRef<SDValue> Ops);

/// Creates a SDDbgValue node.
SDDbgValue *getDbgValue(DIVariable *Var, DIExpression *Expr, SDNode *N,
                        unsigned R, bool IsIndirect, const DebugLoc &DL,
                        unsigned O);

/// Creates a constant SDDbgValue node.
SDDbgValue *getConstantDbgValue(DIVariable *Var, DIExpression *Expr,
                                const Value *C, const DebugLoc &DL,
                                unsigned O);

/// Creates a FrameIndex SDDbgValue node.
SDDbgValue *getFrameIndexDbgValue(DIVariable *Var, DIExpression *Expr,
                                  unsigned FI, bool IsIndirect,
                                  const DebugLoc &DL, unsigned O);

/// Creates a FrameIndex SDDbgValue node.
SDDbgValue *getFrameIndexDbgValue(DIVariable *Var, DIExpression *Expr,
                                  unsigned FI,
                                  ArrayRef<SDNode *> Dependencies,
                                  bool IsIndirect, const DebugLoc &DL,
                                  unsigned O);

/// Creates a VReg SDDbgValue node.
SDDbgValue *getVRegDbgValue(DIVariable *Var, DIExpression *Expr,
                            unsigned VReg, bool IsIndirect,
                            const DebugLoc &DL, unsigned O);

/// Creates a SDDbgValue node from a list of locations.
SDDbgValue *getDbgValueList(DIVariable *Var, DIExpression *Expr,
                            ArrayRef<SDDbgOperand> Locs,
                            ArrayRef<SDNode *> Dependencies, bool IsIndirect,
                            const DebugLoc &DL, unsigned O, bool IsVariadic);

/// Creates a SDDbgLabel node.
SDDbgLabel *getDbgLabel(DILabel *Label, const DebugLoc &DL, unsigned O);

/// Transfer debug values from one node to another, while optionally
/// generating fragment expressions for split-up values. If \p InvalidateDbg
/// is set, debug values are invalidated after they are transferred.
void transferDbgValues(SDValue From, SDValue To, unsigned OffsetInBits = 0,
                       unsigned SizeInBits = 0, bool InvalidateDbg = true);

/// Remove the specified node from the system. If any of its
/// operands then becomes dead, remove them as well. Inform UpdateListener
/// for each node deleted.
void RemoveDeadNode(SDNode *N);

/// This method deletes the unreachable nodes in the
/// given list, and any nodes that become unreachable as a result.
void RemoveDeadNodes(SmallVectorImpl<SDNode *> &DeadNodes);

/// Modify anything using 'From' to use 'To' instead.
/// This can cause recursive merging of nodes in the DAG.  Use the first
/// version if 'From' is known to have a single result, use the second
/// if you have two nodes with identical results (or if 'To' has a superset
/// of the results of 'From'), use the third otherwise.
///
/// These methods all take an optional UpdateListener, which (if not null) is
/// informed about nodes that are deleted and modified due to recursive
/// changes in the dag.
///
/// These functions only replace all existing uses. It's possible that as
/// these replacements are being performed, CSE may cause the From node
/// to be given new uses. These new uses of From are left in place, and
/// not automatically transferred to To.
///
void ReplaceAllUsesWith(SDValue From, SDValue To);
void ReplaceAllUsesWith(SDNode *From, SDNode *To);
void ReplaceAllUsesWith(SDNode *From, const SDValue *To);

/// Replace any uses of From with To, leaving
/// uses of other values produced by From.getNode() alone.
void ReplaceAllUsesOfValueWith(SDValue From, SDValue To);

/// Like ReplaceAllUsesOfValueWith, but for multiple values at once.
/// This correctly handles the case where
/// there is an overlap between the From values and the To values.
void ReplaceAllUsesOfValuesWith(const SDValue *From, const SDValue *To,
                                unsigned Num);

/// If an existing load has uses of its chain, create a token factor node with
/// that chain and the new memory node's chain and update users of the old
/// chain to the token factor. This ensures that the new memory node will have
/// the same relative memory dependency position as the old load. Returns the
/// new merged load chain.
SDValue makeEquivalentMemoryOrdering(SDValue OldChain, SDValue NewMemOpChain);

/// If an existing load has uses of its chain, create a token factor node with
/// that chain and the new memory node's chain and update users of the old
/// chain to the token factor. This ensures that the new memory node will have
/// the same relative memory dependency position as the old load. Returns the
/// new merged load chain.
SDValue makeEquivalentMemoryOrdering(LoadSDNode *OldLoad, SDValue NewMemOp);

/// Topological-sort the AllNodes list and a
/// assign a unique node id for each node in the DAG based on their
/// topological order. Returns the number of nodes.
unsigned AssignTopologicalOrder();

/// Move node N in the AllNodes list to be immediately
/// before the given iterator Position. This may be used to update the
/// topological ordering when the list of nodes is modified.
void RepositionNode(allnodes_iterator Position, SDNode *N) {
  AllNodes.insert(Position, AllNodes.remove(N));
}

/// Returns an APFloat semantics tag appropriate for the given type. If VT is
/// a vector type, the element semantics are returned.
static const fltSemantics &EVTToAPFloatSemantics(EVT VT) {
  switch (VT.getScalarType().getSimpleVT().SimpleTy) {
  default: llvm_unreachable("Unknown FP format")__builtin_unreachable();
  case MVT::f16:     return APFloat::IEEEhalf();
  case MVT::bf16:    return APFloat::BFloat();
  case MVT::f32:     return APFloat::IEEEsingle();
  case MVT::f64:     return APFloat::IEEEdouble();
  case MVT::f80:     return APFloat::x87DoubleExtended();
  case MVT::f128:    return APFloat::IEEEquad();
  case MVT::ppcf128: return APFloat::PPCDoubleDouble();
  }
}

/// Add a dbg_value SDNode. If SD is non-null that means the
/// value is produced by SD.
void AddDbgValue(SDDbgValue *DB, bool isParameter);

/// Add a dbg_label SDNode.
void AddDbgLabel(SDDbgLabel *DB);

/// Get the debug values which reference the given SDNode.
ArrayRef<SDDbgValue*> GetDbgValues(const SDNode* SD) const {
  return DbgInfo->getSDDbgValues(SD);
}

1615public:
/// Return true if there are any SDDbgValue nodes associated
/// with this SelectionDAG.
bool hasDebugValues() const { return !DbgInfo->empty(); }

SDDbgInfo::DbgIterator DbgBegin() const { return DbgInfo->DbgBegin(); }
SDDbgInfo::DbgIterator DbgEnd() const  { return DbgInfo->DbgEnd(); }

SDDbgInfo::DbgIterator ByvalParmDbgBegin() const {
  return DbgInfo->ByvalParmDbgBegin();
}
SDDbgInfo::DbgIterator ByvalParmDbgEnd() const {
  return DbgInfo->ByvalParmDbgEnd();
}

SDDbgInfo::DbgLabelIterator DbgLabelBegin() const {
  return DbgInfo->DbgLabelBegin();
}
SDDbgInfo::DbgLabelIterator DbgLabelEnd() const {
  return DbgInfo->DbgLabelEnd();
}

/// To be invoked on an SDNode that is slated to be erased. This
/// function mirrors \c llvm::salvageDebugInfo.
void salvageDebugInfo(SDNode &N);

void dump() const;

/// In most cases this function returns the ABI alignment for a given type,
/// except for illegal vector types where the alignment exceeds that of the
/// stack. In such cases we attempt to break the vector down to a legal type
/// and return the ABI alignment for that instead.
Align getReducedAlign(EVT VT, bool UseABI);

/// Create a stack temporary based on the size in bytes and the alignment
SDValue CreateStackTemporary(TypeSize Bytes, Align Alignment);

/// Create a stack temporary, suitable for holding the specified value type.
/// If minAlign is specified, the slot size will have at least that alignment.
SDValue CreateStackTemporary(EVT VT, unsigned minAlign = 1);

/// Create a stack temporary suitable for holding either of the specified
/// value types.
SDValue CreateStackTemporary(EVT VT1, EVT VT2);

SDValue FoldSymbolOffset(unsigned Opcode, EVT VT,
                         const GlobalAddressSDNode *GA,
                         const SDNode *N2);

SDValue FoldConstantArithmetic(unsigned Opcode, const SDLoc &DL, EVT VT,
                               ArrayRef<SDValue> Ops);

SDValue FoldConstantVectorArithmetic(unsigned Opcode, const SDLoc &DL, EVT VT,
                                     ArrayRef<SDValue> Ops,
                                     const SDNodeFlags Flags = SDNodeFlags());

/// Fold floating-point operations with 2 operands when both operands are
/// constants and/or undefined.
SDValue foldConstantFPMath(unsigned Opcode, const SDLoc &DL, EVT VT,
                           SDValue N1, SDValue N2);

/// Constant fold a setcc to true or false.
SDValue FoldSetCC(EVT VT, SDValue N1, SDValue N2, ISD::CondCode Cond,
                  const SDLoc &dl);

/// See if the specified operand can be simplified with the knowledge that
/// only the bits specified by DemandedBits are used.  If so, return the
/// simpler operand, otherwise return a null SDValue.
///
/// (This exists alongside SimplifyDemandedBits because GetDemandedBits can
/// simplify nodes with multiple uses more aggressively.)
SDValue GetDemandedBits(SDValue V, const APInt &DemandedBits);

/// See if the specified operand can be simplified with the knowledge that
/// only the bits specified by DemandedBits are used in the elements specified
/// by DemandedElts.  If so, return the simpler operand, otherwise return a
/// null SDValue.
///
/// (This exists alongside SimplifyDemandedBits because GetDemandedBits can
/// simplify nodes with multiple uses more aggressively.)
SDValue GetDemandedBits(SDValue V, const APInt &DemandedBits,
                        const APInt &DemandedElts);

/// Return true if the sign bit of Op is known to be zero.
/// We use this predicate to simplify operations downstream.
bool SignBitIsZero(SDValue Op, unsigned Depth = 0) const;

/// Return true if 'Op & Mask' is known to be zero.  We
/// use this predicate to simplify operations downstream.  Op and Mask are
/// known to be the same type.
bool MaskedValueIsZero(SDValue Op, const APInt &Mask,
                       unsigned Depth = 0) const;

/// Return true if 'Op & Mask' is known to be zero in DemandedElts.  We
/// use this predicate to simplify operations downstream.  Op and Mask are
/// known to be the same type.
bool MaskedValueIsZero(SDValue Op, const APInt &Mask,
                       const APInt &DemandedElts, unsigned Depth = 0) const;

/// Return true if '(Op & Mask) == Mask'.
/// Op and Mask are known to be the same type.
bool MaskedValueIsAllOnes(SDValue Op, const APInt &Mask,
                          unsigned Depth = 0) const;

/// Determine which bits of Op are known to be either zero or one and return
/// them in Known. For vectors, the known bits are those that are shared by
/// every vector element.
/// Targets can implement the computeKnownBitsForTargetNode method in the
/// TargetLowering class to allow target nodes to be understood.
KnownBits computeKnownBits(SDValue Op, unsigned Depth = 0) const;

/// Determine which bits of Op are known to be either zero or one and return
/// them in Known. The DemandedElts argument allows us to only collect the
/// known bits that are shared by the requested vector elements.
/// Targets can implement the computeKnownBitsForTargetNode method in the
/// TargetLowering class to allow target nodes to be understood.
KnownBits computeKnownBits(SDValue Op, const APInt &DemandedElts,
                           unsigned Depth = 0) const;

/// Used to represent the possible overflow behavior of an operation.
/// Never: the operation cannot overflow.
/// Always: the operation will always overflow.
/// Sometime: the operation may or may not overflow.
enum OverflowKind {
  OFK_Never,
  OFK_Sometime,
  OFK_Always,
};

/// Determine if the result of the addition of 2 node can overflow.
OverflowKind computeOverflowKind(SDValue N0, SDValue N1) const;

/// Test if the given value is known to have exactly one bit set. This differs
/// from computeKnownBits in that it doesn't necessarily determine which bit
/// is set.
bool isKnownToBeAPowerOfTwo(SDValue Val) const;

/// Return the number of times the sign bit of the register is replicated into
/// the other bits. We know that at least 1 bit is always equal to the sign
/// bit (itself), but other cases can give us information. For example,
/// immediately after an "SRA X, 2", we know that the top 3 bits are all equal
/// to each other, so we return 3. Targets can implement the
/// ComputeNumSignBitsForTarget method in the TargetLowering class to allow
/// target nodes to be understood.
unsigned ComputeNumSignBits(SDValue Op, unsigned Depth = 0) const;

/// Return the number of times the sign bit of the register is replicated into
/// the other bits. We know that at least 1 bit is always equal to the sign
/// bit (itself), but other cases can give us information. For example,
/// immediately after an "SRA X, 2", we know that the top 3 bits are all equal
/// to each other, so we return 3. The DemandedElts argument allows
/// us to only collect the minimum sign bits of the requested vector elements.
/// Targets can implement the ComputeNumSignBitsForTarget method in the
/// TargetLowering class to allow target nodes to be understood.
unsigned ComputeNumSignBits(SDValue Op, const APInt &DemandedElts,
                            unsigned Depth = 0) const;

/// Return true if this function can prove that \p Op is never poison
/// and, if \p PoisonOnly is false, does not have undef bits.
bool isGuaranteedNotToBeUndefOrPoison(SDValue Op, bool PoisonOnly = false,
                                      unsigned Depth = 0) const;

/// Return true if this function can prove that \p Op is never poison
/// and, if \p PoisonOnly is false, does not have undef bits. The DemandedElts
/// argument limits the check to the requested vector elements.
bool isGuaranteedNotToBeUndefOrPoison(SDValue Op, const APInt &DemandedElts,
                                      bool PoisonOnly = false,
                                      unsigned Depth = 0) const;

/// Return true if this function can prove that \p Op is never poison.
bool isGuaranteedNotToBePoison(SDValue Op, unsigned Depth = 0) const {
  return isGuaranteedNotToBeUndefOrPoison(Op, /*PoisonOnly*/ true, Depth);
}

/// Return true if this function can prove that \p Op is never poison. The
/// DemandedElts argument limits the check to the requested vector elements.
bool isGuaranteedNotToBePoison(SDValue Op, const APInt &DemandedElts,
                               unsigned Depth = 0) const {
  return isGuaranteedNotToBeUndefOrPoison(Op, DemandedElts,
                                          /*PoisonOnly*/ true, Depth);
}

/// Return true if the specified operand is an ISD::ADD with a ConstantSDNode
/// on the right-hand side, or if it is an ISD::OR with a ConstantSDNode that
/// is guaranteed to have the same semantics as an ADD. This handles the
/// equivalence:
///     X|Cst == X+Cst iff X&Cst = 0.
bool isBaseWithConstantOffset(SDValue Op) const;

/// Test whether the given SDValue is known to never be NaN. If \p SNaN is
/// true, returns if \p Op is known to never be a signaling NaN (it may still
/// be a qNaN).
bool isKnownNeverNaN(SDValue Op, bool SNaN = false, unsigned Depth = 0) const;

/// \returns true if \p Op is known to never be a signaling NaN.
bool isKnownNeverSNaN(SDValue Op, unsigned Depth = 0) const {
  return isKnownNeverNaN(Op, true, Depth);
}

/// Test whether the given floating point SDValue is known to never be
/// positive or negative zero.
bool isKnownNeverZeroFloat(SDValue Op) const;

/// Test whether the given SDValue is known to contain non-zero value(s).
bool isKnownNeverZero(SDValue Op) const;

/// Test whether two SDValues are known to compare equal. This
/// is true if they are the same value, or if one is negative zero and the
/// other positive zero.
bool isEqualTo(SDValue A, SDValue B) const;

/// Return true if A and B have no common bits set. As an example, this can
/// allow an 'add' to be transformed into an 'or'.
bool haveNoCommonBitsSet(SDValue A, SDValue B) const;

/// Test whether \p V has a splatted value for all the demanded elements.
///
/// On success \p UndefElts will indicate the elements that have UNDEF
/// values instead of the splat value, this is only guaranteed to be correct
/// for \p DemandedElts.
///
/// NOTE: The function will return true for a demanded splat of UNDEF values.
bool isSplatValue(SDValue V, const APInt &DemandedElts, APInt &UndefElts,
                  unsigned Depth = 0);

/// Test whether \p V has a splatted value.
bool isSplatValue(SDValue V, bool AllowUndefs = false);

/// If V is a splatted value, return the source vector and its splat index.
SDValue getSplatSourceVector(SDValue V, int &SplatIndex);

/// If V is a splat vector, return its scalar source operand by extracting
/// that element from the source vector. If LegalTypes is true, this method
/// may only return a legally-typed splat value. If it cannot legalize the
/// splatted value it will return SDValue().
SDValue getSplatValue(SDValue V, bool LegalTypes = false);

/// If a SHL/SRA/SRL node \p V has a constant or splat constant shift amount
/// that is less than the element bit-width of the shift node, return it.
const APInt *getValidShiftAmountConstant(SDValue V,
                                         const APInt &DemandedElts) const;

/// If a SHL/SRA/SRL node \p V has constant shift amounts that are all less
/// than the element bit-width of the shift node, return the minimum value.
const APInt *
getValidMinimumShiftAmountConstant(SDValue V,
                                   const APInt &DemandedElts) const;

/// If a SHL/SRA/SRL node \p V has constant shift amounts that are all less
/// than the element bit-width of the shift node, return the maximum value.
const APInt *
getValidMaximumShiftAmountConstant(SDValue V,
                                   const APInt &DemandedElts) const;

/// Match a binop + shuffle pyramid that represents a horizontal reduction
/// over the elements of a vector starting from the EXTRACT_VECTOR_ELT node /p
/// Extract. The reduction must use one of the opcodes listed in /p
/// CandidateBinOps and on success /p BinOp will contain the matching opcode.
/// Returns the vector that is being reduced on, or SDValue() if a reduction
/// was not matched. If \p AllowPartials is set then in the case of a
/// reduction pattern that only matches the first few stages, the extracted
/// subvector of the start of the reduction is returned.
SDValue matchBinOpReduction(SDNode *Extract, ISD::NodeType &BinOp,
                            ArrayRef<ISD::NodeType> CandidateBinOps,
                            bool AllowPartials = false);

/// Utility function used by legalize and lowering to
/// "unroll" a vector operation by splitting out the scalars and operating
/// on each element individually.  If the ResNE is 0, fully unroll the vector
/// op. If ResNE is less than the width of the vector op, unroll up to ResNE.
/// If the  ResNE is greater than the width of the vector op, unroll the
/// vector op and fill the end of the resulting vector with UNDEFS.
SDValue UnrollVectorOp(SDNode *N, unsigned ResNE = 0);

/// Like UnrollVectorOp(), but for the [US](ADD|SUB|MUL)O family of opcodes.
/// This is a separate function because those opcodes have two results.
std::pair<SDValue, SDValue> UnrollVectorOverflowOp(SDNode *N,
                                                   unsigned ResNE = 0);

/// Return true if loads are next to each other and can be
/// merged. Check that both are nonvolatile and if LD is loading
/// 'Bytes' bytes from a location that is 'Dist' units away from the
/// location that the 'Base' load is loading from.
bool areNonVolatileConsecutiveLoads(LoadSDNode *LD, LoadSDNode *Base,
                                    unsigned Bytes, int Dist) const;

/// Infer alignment of a load / store address. Return None if it cannot be
/// inferred.
MaybeAlign InferPtrAlign(SDValue Ptr) const;

/// Compute the VTs needed for the low/hi parts of a type
/// which is split (or expanded) into two not necessarily identical pieces.
std::pair<EVT, EVT> GetSplitDestVTs(const EVT &VT) const;

/// Compute the VTs needed for the low/hi parts of a type, dependent on an
/// enveloping VT that has been split into two identical pieces. Sets the
/// HisIsEmpty flag when hi type has zero storage size.
std::pair<EVT, EVT> GetDependentSplitDestVTs(const EVT &VT, const EVT &EnvVT,
                                             bool *HiIsEmpty) const;

/// Split the vector with EXTRACT_SUBVECTOR using the provides
/// VTs and return the low/high part.
std::pair<SDValue, SDValue> SplitVector(const SDValue &N, const SDLoc &DL,
                                        const EVT &LoVT, const EVT &HiVT);

/// Split the vector with EXTRACT_SUBVECTOR and return the low/high part.
std::pair<SDValue, SDValue> SplitVector(const SDValue &N, const SDLoc &DL) {
  EVT LoVT, HiVT;
  std::tie(LoVT, HiVT) = GetSplitDestVTs(N.getValueType());
  return SplitVector(N, DL, LoVT, HiVT);
}

/// Split the node's operand with EXTRACT_SUBVECTOR and
/// return the low/high part.
std::pair<SDValue, SDValue> SplitVectorOperand(const SDNode *N, unsigned OpNo)
{
  return SplitVector(N->getOperand(OpNo), SDLoc(N));
}

/// Widen the vector up to the next power of two using INSERT_SUBVECTOR.
SDValue WidenVector(const SDValue &N, const SDLoc &DL);

/// Append the extracted elements from Start to Count out of the vector Op in
/// Args. If Count is 0, all of the elements will be extracted. The extracted
/// elements will have type EVT if it is provided, and otherwise their type
/// will be Op's element type.
void ExtractVectorElements(SDValue Op, SmallVectorImpl<SDValue> &Args,
                           unsigned Start = 0, unsigned Count = 0,
                           EVT EltVT = EVT());

/// Compute the default alignment value for the given type.
Align getEVTAlign(EVT MemoryVT) const;
/// Compute the default alignment value for the given type.
/// FIXME: Remove once transition to Align is over.
inline unsigned getEVTAlignment(EVT MemoryVT) const {
  return getEVTAlign(MemoryVT).value();
}

/// Test whether the given value is a constant int or similar node.
SDNode *isConstantIntBuildVectorOrConstantInt(SDValue N) const;

/// Test whether the given value is a constant FP or similar node.
SDNode *isConstantFPBuildVectorOrConstantFP(SDValue N) const ;

/// \returns true if \p N is any kind of constant or build_vector of
/// constants, int or float. If a vector, it may not necessarily be a splat.
inline bool isConstantValueOfAnyType(SDValue N) const {
  return isConstantIntBuildVectorOrConstantInt(N) ||
         isConstantFPBuildVectorOrConstantFP(N);
}

void addCallSiteInfo(const SDNode *CallNode, CallSiteInfoImpl &&CallInfo) {
  SDCallSiteDbgInfo[CallNode].CSInfo = std::move(CallInfo);
}

CallSiteInfo getSDCallSiteInfo(const SDNode *CallNode) {
  auto I = SDCallSiteDbgInfo.find(CallNode);
  if (I != SDCallSiteDbgInfo.end())
    return std::move(I->second).CSInfo;
  return CallSiteInfo();
}

void addHeapAllocSite(const SDNode *Node, MDNode *MD) {
  SDCallSiteDbgInfo[Node].HeapAllocSite = MD;
}

/// Return the HeapAllocSite type associated with the SDNode, if it exists.
MDNode *getHeapAllocSite(const SDNode *Node) {
  auto It = SDCallSiteDbgInfo.find(Node);
  if (It == SDCallSiteDbgInfo.end())
    return nullptr;
  return It->second.HeapAllocSite;
}

void addNoMergeSiteInfo(const SDNode *Node, bool NoMerge) {
  if (NoMerge)
    SDCallSiteDbgInfo[Node].NoMerge = NoMerge;
}

bool getNoMergeSiteInfo(const SDNode *Node) {
  auto I = SDCallSiteDbgInfo.find(Node);
  if (I == SDCallSiteDbgInfo.end())
    return false;
  return I->second.NoMerge;
}

/// Return the current function's default denormal handling kind for the given
/// floating point type.
DenormalMode getDenormalMode(EVT VT) const {
  return MF->getDenormalMode(EVTToAPFloatSemantics(VT));
}

bool shouldOptForSize() const;

/// Get the (commutative) neutral element for the given opcode, if it exists.
SDValue getNeutralElement(unsigned Opcode, const SDLoc &DL, EVT VT,
                          SDNodeFlags Flags);

2013private:
void InsertNode(SDNode *N);
bool RemoveNodeFromCSEMaps(SDNode *N);
void AddModifiedNodeToCSEMaps(SDNode *N);
SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op, void *&InsertPos);
SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op1, SDValue Op2,
                             void *&InsertPos);
SDNode *FindModifiedNodeSlot(SDNode *N, ArrayRef<SDValue> Ops,
                             void *&InsertPos);
SDNode *UpdateSDLocOnMergeSDNode(SDNode *N, const SDLoc &loc);

void DeleteNodeNotInCSEMaps(SDNode *N);
void DeallocateNode(SDNode *N);

void allnodes_clear();

/// Look up the node specified by ID in CSEMap.  If it exists, return it.  If
/// not, return the insertion token that will make insertion faster.  This
/// overload is for nodes other than Constant or ConstantFP, use the other one
/// for those.
SDNode *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos);

/// Look up the node specified by ID in CSEMap.  If it exists, return it.  If
/// not, return the insertion token that will make insertion faster.  Performs
/// additional processing for constant nodes.
SDNode *FindNodeOrInsertPos(const FoldingSetNodeID &ID, const SDLoc &DL,
                            void *&InsertPos);

/// List of non-single value types.
FoldingSet<SDVTListNode> VTListMap;

/// Maps to auto-CSE operations.
std::vector<CondCodeSDNode*> CondCodeNodes;

std::vector<SDNode*> ValueTypeNodes;
std::map<EVT, SDNode*, EVT::compareRawBits> ExtendedValueTypeNodes;
StringMap<SDNode*> ExternalSymbols;

std::map<std::pair<std::string, unsigned>, SDNode *> TargetExternalSymbols;
DenseMap<MCSymbol *, SDNode *> MCSymbols;

FlagInserter *Inserter = nullptr;
2055};

2057template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
using nodes_iterator = pointer_iterator<SelectionDAG::allnodes_iterator>;

static nodes_iterator nodes_begin(SelectionDAG *G) {
  return nodes_iterator(G->allnodes_begin());
}

static nodes_iterator nodes_end(SelectionDAG *G) {
  return nodes_iterator(G->allnodes_end());
}
2067};

2069} // end namespace llvm

2071#endif // LLVM_CODEGEN_SELECTIONDAG_H

←

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/CodeGen/SelectionDAGNodes.h

1//===- llvm/CodeGen/SelectionDAGNodes.h - SelectionDAG Nodes ----*- C++ -*-===//
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 file declares the SDNode class and derived classes, which are used to
10// represent the nodes and operations present in a SelectionDAG.  These nodes
11// and operations are machine code level operations, with some similarities to
12// the GCC RTL representation.
13//
14// Clients should include the SelectionDAG.h file instead of this file directly.
15//
16//===----------------------------------------------------------------------===//

18#ifndef LLVM_CODEGEN_SELECTIONDAGNODES_H
19#define LLVM_CODEGEN_SELECTIONDAGNODES_H

21#include "llvm/ADT/APFloat.h"
22#include "llvm/ADT/ArrayRef.h"
23#include "llvm/ADT/BitVector.h"
24#include "llvm/ADT/FoldingSet.h"
25#include "llvm/ADT/GraphTraits.h"
26#include "llvm/ADT/SmallPtrSet.h"
27#include "llvm/ADT/SmallVector.h"
28#include "llvm/ADT/ilist_node.h"
29#include "llvm/ADT/iterator.h"
30#include "llvm/ADT/iterator_range.h"
31#include "llvm/CodeGen/ISDOpcodes.h"
32#include "llvm/CodeGen/MachineMemOperand.h"
33#include "llvm/CodeGen/Register.h"
34#include "llvm/CodeGen/ValueTypes.h"
35#include "llvm/IR/Constants.h"
36#include "llvm/IR/DebugLoc.h"
37#include "llvm/IR/Instruction.h"
38#include "llvm/IR/Instructions.h"
39#include "llvm/IR/Metadata.h"
40#include "llvm/IR/Operator.h"
41#include "llvm/Support/AlignOf.h"
42#include "llvm/Support/AtomicOrdering.h"
43#include "llvm/Support/Casting.h"
44#include "llvm/Support/ErrorHandling.h"
45#include "llvm/Support/MachineValueType.h"
46#include "llvm/Support/TypeSize.h"
47#include <algorithm>
48#include <cassert>
49#include <climits>
50#include <cstddef>
51#include <cstdint>
52#include <cstring>
53#include <iterator>
54#include <string>
55#include <tuple>

57namespace llvm {

59class APInt;
60class Constant;
61template <typename T> struct DenseMapInfo;
62class GlobalValue;
63class MachineBasicBlock;
64class MachineConstantPoolValue;
65class MCSymbol;
66class raw_ostream;
67class SDNode;
68class SelectionDAG;
69class Type;
70class Value;

72void checkForCycles(const SDNode *N, const SelectionDAG *DAG = nullptr,
                  bool force = false);

75/// This represents a list of ValueType's that has been intern'd by
76/// a SelectionDAG.  Instances of this simple value class are returned by
77/// SelectionDAG::getVTList(...).
78///
79struct SDVTList {
const EVT *VTs;
unsigned int NumVTs;
82};

84namespace ISD {

/// Node predicates

88/// If N is a BUILD_VECTOR or SPLAT_VECTOR node whose elements are all the
89/// same constant or undefined, return true and return the constant value in
90/// \p SplatValue.
91bool isConstantSplatVector(const SDNode *N, APInt &SplatValue);

93/// Return true if the specified node is a BUILD_VECTOR or SPLAT_VECTOR where
94/// all of the elements are ~0 or undef. If \p BuildVectorOnly is set to
95/// true, it only checks BUILD_VECTOR.
96bool isConstantSplatVectorAllOnes(const SDNode *N,
                                bool BuildVectorOnly = false);

99/// Return true if the specified node is a BUILD_VECTOR or SPLAT_VECTOR where
100/// all of the elements are 0 or undef. If \p BuildVectorOnly is set to true, it
101/// only checks BUILD_VECTOR.
102bool isConstantSplatVectorAllZeros(const SDNode *N,
                                 bool BuildVectorOnly = false);

105/// Return true if the specified node is a BUILD_VECTOR where all of the
106/// elements are ~0 or undef.
107bool isBuildVectorAllOnes(const SDNode *N);

109/// Return true if the specified node is a BUILD_VECTOR where all of the
110/// elements are 0 or undef.
111bool isBuildVectorAllZeros(const SDNode *N);

113/// Return true if the specified node is a BUILD_VECTOR node of all
114/// ConstantSDNode or undef.
115bool isBuildVectorOfConstantSDNodes(const SDNode *N);

117/// Return true if the specified node is a BUILD_VECTOR node of all
118/// ConstantFPSDNode or undef.
119bool isBuildVectorOfConstantFPSDNodes(const SDNode *N);

121/// Return true if the node has at least one operand and all operands of the
122/// specified node are ISD::UNDEF.
123bool allOperandsUndef(const SDNode *N);

125} // end namespace ISD

127//===----------------------------------------------------------------------===//
128/// Unlike LLVM values, Selection DAG nodes may return multiple
129/// values as the result of a computation.  Many nodes return multiple values,
130/// from loads (which define a token and a return value) to ADDC (which returns
131/// a result and a carry value), to calls (which may return an arbitrary number
132/// of values).
133///
134/// As such, each use of a SelectionDAG computation must indicate the node that
135/// computes it as well as which return value to use from that node.  This pair
136/// of information is represented with the SDValue value type.
137///
138class SDValue {
friend struct DenseMapInfo<SDValue>;

SDNode *Node = nullptr; // The node defining the value we are using.
unsigned ResNo = 0;     // Which return value of the node we are using.

144public:
SDValue() = default;
SDValue(SDNode *node, unsigned resno);

/// get the index which selects a specific result in the SDNode
unsigned getResNo() const { return ResNo; }

/// get the SDNode which holds the desired result
SDNode *getNode() const { return Node; }

/// set the SDNode
void setNode(SDNode *N) { Node = N; }

inline SDNode *operator->() const { return Node; }

bool operator==(const SDValue &O) const {
  return Node == O.Node && ResNo == O.ResNo;
}
bool operator!=(const SDValue &O) const {
  return !operator==(O);
}
bool operator<(const SDValue &O) const {
  return std::tie(Node, ResNo) < std::tie(O.Node, O.ResNo);
}
explicit operator bool() const {
  return Node != nullptr;
}

SDValue getValue(unsigned R) const {
  return SDValue(Node, R);
}

/// Return true if this node is an operand of N.
bool isOperandOf(const SDNode *N) const;

/// Return the ValueType of the referenced return value.
inline EVT getValueType() const;

/// Return the simple ValueType of the referenced return value.
MVT getSimpleValueType() const {
  return getValueType().getSimpleVT();
}

/// Returns the size of the value in bits.
///
/// If the value type is a scalable vector type, the scalable property will
/// be set and the runtime size will be a positive integer multiple of the
/// base size.
TypeSize getValueSizeInBits() const {
  return getValueType().getSizeInBits();
}

uint64_t getScalarValueSizeInBits() const {
  return getValueType().getScalarType().getFixedSizeInBits();
}

// Forwarding methods - These forward to the corresponding methods in SDNode.
inline unsigned getOpcode() const;
inline unsigned getNumOperands() const;
inline const SDValue &getOperand(unsigned i) const;
inline uint64_t getConstantOperandVal(unsigned i) const;
inline const APInt &getConstantOperandAPInt(unsigned i) const;
inline bool isTargetMemoryOpcode() const;
inline bool isTargetOpcode() const;
inline bool isMachineOpcode() const;
inline bool isUndef() const;
inline unsigned getMachineOpcode() const;
inline const DebugLoc &getDebugLoc() const;
inline void dump() const;
inline void dump(const SelectionDAG *G) const;
inline void dumpr() const;
inline void dumpr(const SelectionDAG *G) const;

/// Return true if this operand (which must be a chain) reaches the
/// specified operand without crossing any side-effecting instructions.
/// In practice, this looks through token factors and non-volatile loads.
/// In order to remain efficient, this only
/// looks a couple of nodes in, it does not do an exhaustive search.
bool reachesChainWithoutSideEffects(SDValue Dest,
                                    unsigned Depth = 2) const;

/// Return true if there are no nodes using value ResNo of Node.
inline bool use_empty() const;

/// Return true if there is exactly one node using value ResNo of Node.
inline bool hasOneUse() const;
230};

232template<> struct DenseMapInfo<SDValue> {
static inline SDValue getEmptyKey() {
  SDValue V;
  V.ResNo = -1U;
  return V;
}

static inline SDValue getTombstoneKey() {
  SDValue V;
  V.ResNo = -2U;
  return V;
}

static unsigned getHashValue(const SDValue &Val) {
  return ((unsigned)((uintptr_t)Val.getNode() >> 4) ^
          (unsigned)((uintptr_t)Val.getNode() >> 9)) + Val.getResNo();
}

static bool isEqual(const SDValue &LHS, const SDValue &RHS) {
  return LHS == RHS;
}
253};

255/// Allow casting operators to work directly on
256/// SDValues as if they were SDNode*'s.
257template<> struct simplify_type<SDValue> {
using SimpleType = SDNode *;

static SimpleType getSimplifiedValue(SDValue &Val) {
  return Val.getNode();
}
263};
264template<> struct simplify_type<const SDValue> {
using SimpleType = /*const*/ SDNode *;

static SimpleType getSimplifiedValue(const SDValue &Val) {
  return Val.getNode();
}
270};

272/// Represents a use of a SDNode. This class holds an SDValue,
273/// which records the SDNode being used and the result number, a
274/// pointer to the SDNode using the value, and Next and Prev pointers,
275/// which link together all the uses of an SDNode.
276///
277class SDUse {
/// Val - The value being used.
SDValue Val;
/// User - The user of this value.
SDNode *User = nullptr;
/// Prev, Next - Pointers to the uses list of the SDNode referred by
/// this operand.
SDUse **Prev = nullptr;
SDUse *Next = nullptr;

287public:
SDUse() = default;
SDUse(const SDUse &U) = delete;
SDUse &operator=(const SDUse &) = delete;

/// Normally SDUse will just implicitly convert to an SDValue that it holds.
operator const SDValue&() const { return Val; }

/// If implicit conversion to SDValue doesn't work, the get() method returns
/// the SDValue.
const SDValue &get() const { return Val; }

/// This returns the SDNode that contains this Use.
SDNode *getUser() { return User; }

/// Get the next SDUse in the use list.
SDUse *getNext() const { return Next; }

/// Convenience function for get().getNode().
SDNode *getNode() const { return Val.getNode(); }
/// Convenience function for get().getResNo().
unsigned getResNo() const { return Val.getResNo(); }
/// Convenience function for get().getValueType().
EVT getValueType() const { return Val.getValueType(); }

/// Convenience function for get().operator==
bool operator==(const SDValue &V) const {
  return Val == V;
}

/// Convenience function for get().operator!=
bool operator!=(const SDValue &V) const {
  return Val != V;
}

/// Convenience function for get().operator<
bool operator<(const SDValue &V) const {
  return Val < V;
}

327private:
friend class SelectionDAG;
friend class SDNode;
// TODO: unfriend HandleSDNode once we fix its operand handling.
friend class HandleSDNode;

void setUser(SDNode *p) { User = p; }

/// Remove this use from its existing use list, assign it the
/// given value, and add it to the new value's node's use list.
inline void set(const SDValue &V);
/// Like set, but only supports initializing a newly-allocated
/// SDUse with a non-null value.
inline void setInitial(const SDValue &V);
/// Like set, but only sets the Node portion of the value,
/// leaving the ResNo portion unmodified.
inline void setNode(SDNode *N);

void addToList(SDUse **List) {
  Next = *List;
  if (Next) Next->Prev = &Next;
  Prev = List;
  *List = this;
}

void removeFromList() {
  *Prev = Next;
  if (Next) Next->Prev = Prev;
}
356};

358/// simplify_type specializations - Allow casting operators to work directly on
359/// SDValues as if they were SDNode*'s.
360template<> struct simplify_type<SDUse> {
using SimpleType = SDNode *;

static SimpleType getSimplifiedValue(SDUse &Val) {
  return Val.getNode();
}
366};

368/// These are IR-level optimization flags that may be propagated to SDNodes.
369/// TODO: This data structure should be shared by the IR optimizer and the
370/// the backend.
371struct SDNodeFlags {
372private:
bool NoUnsignedWrap : 1;
bool NoSignedWrap : 1;
bool Exact : 1;
bool NoNaNs : 1;
bool NoInfs : 1;
bool NoSignedZeros : 1;
bool AllowReciprocal : 1;
bool AllowContract : 1;
bool ApproximateFuncs : 1;
bool AllowReassociation : 1;

// We assume instructions do not raise floating-point exceptions by default,
// and only those marked explicitly may do so.  We could choose to represent
// this via a positive "FPExcept" flags like on the MI level, but having a
// negative "NoFPExcept" flag here (that defaults to true) makes the flag
// intersection logic more straightforward.
bool NoFPExcept : 1;

391public:
/// Default constructor turns off all optimization flags.
SDNodeFlags()
    : NoUnsignedWrap(false), NoSignedWrap(false), Exact(false), NoNaNs(false),
      NoInfs(false), NoSignedZeros(false), AllowReciprocal(false),
      AllowContract(false), ApproximateFuncs(false),
      AllowReassociation(false), NoFPExcept(false) {}

/// Propagate the fast-math-flags from an IR FPMathOperator.
void copyFMF(const FPMathOperator &FPMO) {
  setNoNaNs(FPMO.hasNoNaNs());
  setNoInfs(FPMO.hasNoInfs());
  setNoSignedZeros(FPMO.hasNoSignedZeros());
  setAllowReciprocal(FPMO.hasAllowReciprocal());
  setAllowContract(FPMO.hasAllowContract());
  setApproximateFuncs(FPMO.hasApproxFunc());
  setAllowReassociation(FPMO.hasAllowReassoc());
}

// These are mutators for each flag.
void setNoUnsignedWrap(bool b) { NoUnsignedWrap = b; }
void setNoSignedWrap(bool b) { NoSignedWrap = b; }
void setExact(bool b) { Exact = b; }
void setNoNaNs(bool b) { NoNaNs = b; }
void setNoInfs(bool b) { NoInfs = b; }
void setNoSignedZeros(bool b) { NoSignedZeros = b; }
void setAllowReciprocal(bool b) { AllowReciprocal = b; }
void setAllowContract(bool b) { AllowContract = b; }
void setApproximateFuncs(bool b) { ApproximateFuncs = b; }
void setAllowReassociation(bool b) { AllowReassociation = b; }
void setNoFPExcept(bool b) { NoFPExcept = b; }

// These are accessors for each flag.
bool hasNoUnsignedWrap() const { return NoUnsignedWrap; }
bool hasNoSignedWrap() const { return NoSignedWrap; }
bool hasExact() const { return Exact; }
bool hasNoNaNs() const { return NoNaNs; }
bool hasNoInfs() const { return NoInfs; }
bool hasNoSignedZeros() const { return NoSignedZeros; }
bool hasAllowReciprocal() const { return AllowReciprocal; }
bool hasAllowContract() const { return AllowContract; }
bool hasApproximateFuncs() const { return ApproximateFuncs; }
bool hasAllowReassociation() const { return AllowReassociation; }
bool hasNoFPExcept() const { return NoFPExcept; }

/// Clear any flags in this flag set that aren't also set in Flags. All
/// flags will be cleared if Flags are undefined.
void intersectWith(const SDNodeFlags Flags) {
  NoUnsignedWrap &= Flags.NoUnsignedWrap;
  NoSignedWrap &= Flags.NoSignedWrap;
  Exact &= Flags.Exact;
  NoNaNs &= Flags.NoNaNs;
  NoInfs &= Flags.NoInfs;
  NoSignedZeros &= Flags.NoSignedZeros;
  AllowReciprocal &= Flags.AllowReciprocal;
  AllowContract &= Flags.AllowContract;
  ApproximateFuncs &= Flags.ApproximateFuncs;
  AllowReassociation &= Flags.AllowReassociation;
  NoFPExcept &= Flags.NoFPExcept;
}
451};

453/// Represents one node in the SelectionDAG.
454///
455class SDNode : public FoldingSetNode, public ilist_node<SDNode> {
456private:
/// The operation that this node performs.
int16_t NodeType;

460protected:
// We define a set of mini-helper classes to help us interpret the bits in our
// SubclassData.  These are designed to fit within a uint16_t so they pack
// with NodeType.

465#if defined(_AIX) && (!defined(__GNUC__4) || defined(__clang__1))
466// Except for GCC; by default, AIX compilers store bit-fields in 4-byte words
467// and give the `pack` pragma push semantics.
468#define BEGIN_TWO_BYTE_PACK() _Pragma("pack(2)")pack(2)
469#define END_TWO_BYTE_PACK() _Pragma("pack(pop)")pack(pop)
470#else
471#define BEGIN_TWO_BYTE_PACK()
472#define END_TWO_BYTE_PACK()
473#endif

475BEGIN_TWO_BYTE_PACK()
class SDNodeBitfields {
  friend class SDNode;
  friend class MemIntrinsicSDNode;
  friend class MemSDNode;
  friend class SelectionDAG;

  uint16_t HasDebugValue : 1;
  uint16_t IsMemIntrinsic : 1;
  uint16_t IsDivergent : 1;
};
enum { NumSDNodeBits = 3 };

class ConstantSDNodeBitfields {
  friend class ConstantSDNode;

  uint16_t : NumSDNodeBits;

  uint16_t IsOpaque : 1;
};

class MemSDNodeBitfields {
  friend class MemSDNode;
  friend class MemIntrinsicSDNode;
  friend class AtomicSDNode;

  uint16_t : NumSDNodeBits;

  uint16_t IsVolatile : 1;
  uint16_t IsNonTemporal : 1;
  uint16_t IsDereferenceable : 1;
  uint16_t IsInvariant : 1;
};
enum { NumMemSDNodeBits = NumSDNodeBits + 4 };

class LSBaseSDNodeBitfields {
  friend class LSBaseSDNode;
  friend class MaskedLoadStoreSDNode;
  friend class MaskedGatherScatterSDNode;

  uint16_t : NumMemSDNodeBits;

  // This storage is shared between disparate class hierarchies to hold an
  // enumeration specific to the class hierarchy in use.
  //   LSBaseSDNode => enum ISD::MemIndexedMode
  //   MaskedLoadStoreBaseSDNode => enum ISD::MemIndexedMode
  //   MaskedGatherScatterSDNode => enum ISD::MemIndexType
  uint16_t AddressingMode : 3;
};
enum { NumLSBaseSDNodeBits = NumMemSDNodeBits + 3 };

class LoadSDNodeBitfields {
  friend class LoadSDNode;
  friend class MaskedLoadSDNode;
  friend class MaskedGatherSDNode;

  uint16_t : NumLSBaseSDNodeBits;

  uint16_t ExtTy : 2; // enum ISD::LoadExtType
  uint16_t IsExpanding : 1;
};

class StoreSDNodeBitfields {
  friend class StoreSDNode;
  friend class MaskedStoreSDNode;
  friend class MaskedScatterSDNode;

  uint16_t : NumLSBaseSDNodeBits;

  uint16_t IsTruncating : 1;
  uint16_t IsCompressing : 1;
};

union {
  char RawSDNodeBits[sizeof(uint16_t)];
  SDNodeBitfields SDNodeBits;
  ConstantSDNodeBitfields ConstantSDNodeBits;
  MemSDNodeBitfields MemSDNodeBits;
  LSBaseSDNodeBitfields LSBaseSDNodeBits;
  LoadSDNodeBitfields LoadSDNodeBits;
  StoreSDNodeBitfields StoreSDNodeBits;
};
557END_TWO_BYTE_PACK()
558#undef BEGIN_TWO_BYTE_PACK
559#undef END_TWO_BYTE_PACK

// RawSDNodeBits must cover the entirety of the union.  This means that all of
// the union's members must have size <= RawSDNodeBits.  We write the RHS as
// "2" instead of sizeof(RawSDNodeBits) because MSVC can't handle the latter.
static_assert(sizeof(SDNodeBitfields) <= 2, "field too wide");
static_assert(sizeof(ConstantSDNodeBitfields) <= 2, "field too wide");
static_assert(sizeof(MemSDNodeBitfields) <= 2, "field too wide");
static_assert(sizeof(LSBaseSDNodeBitfields) <= 2, "field too wide");
static_assert(sizeof(LoadSDNodeBitfields) <= 2, "field too wide");
static_assert(sizeof(StoreSDNodeBitfields) <= 2, "field too wide");

571private:
friend class SelectionDAG;
// TODO: unfriend HandleSDNode once we fix its operand handling.
friend class HandleSDNode;

/// Unique id per SDNode in the DAG.
int NodeId = -1;

/// The values that are used by this operation.
SDUse *OperandList = nullptr;

/// The types of the values this node defines.  SDNode's may
/// define multiple values simultaneously.
const EVT *ValueList;

/// List of uses for this SDNode.
SDUse *UseList = nullptr;

/// The number of entries in the Operand/Value list.
unsigned short NumOperands = 0;
unsigned short NumValues;

// The ordering of the SDNodes. It roughly corresponds to the ordering of the
// original LLVM instructions.
// This is used for turning off scheduling, because we'll forgo
// the normal scheduling algorithms and output the instructions according to
// this ordering.
unsigned IROrder;

/// Source line information.
DebugLoc debugLoc;

/// Return a pointer to the specified value type.
static const EVT *getValueTypeList(EVT VT);

SDNodeFlags Flags;

608public:
/// Unique and persistent id per SDNode in the DAG.
/// Used for debug printing.
uint16_t PersistentId;

//===--------------------------------------------------------------------===//
//  Accessors
//

/// Return the SelectionDAG opcode value for this node. For
/// pre-isel nodes (those for which isMachineOpcode returns false), these
/// are the opcode values in the ISD and <target>ISD namespaces. For
/// post-isel opcodes, see getMachineOpcode.
unsigned getOpcode()  const { return (unsigned short)NodeType; }

/// Test if this node has a target-specific opcode (in the
/// \<target\>ISD namespace).
bool isTargetOpcode() const { return NodeType >= ISD::BUILTIN_OP_END; }

/// Test if this node has a target-specific opcode that may raise
/// FP exceptions (in the \<target\>ISD namespace and greater than
/// FIRST_TARGET_STRICTFP_OPCODE).  Note that all target memory
/// opcode are currently automatically considered to possibly raise
/// FP exceptions as well.
bool isTargetStrictFPOpcode() const {
  return NodeType >= ISD::FIRST_TARGET_STRICTFP_OPCODE;
}

/// Test if this node has a target-specific
/// memory-referencing opcode (in the \<target\>ISD namespace and
/// greater than FIRST_TARGET_MEMORY_OPCODE).
bool isTargetMemoryOpcode() const {
  return NodeType >= ISD::FIRST_TARGET_MEMORY_OPCODE;
}

/// Return true if the type of the node type undefined.
bool isUndef() const { return NodeType == ISD::UNDEF; }

/// Test if this node is a memory intrinsic (with valid pointer information).
/// INTRINSIC_W_CHAIN and INTRINSIC_VOID nodes are sometimes created for
/// non-memory intrinsics (with chains) that are not really instances of
/// MemSDNode. For such nodes, we need some extra state to determine the
/// proper classof relationship.
bool isMemIntrinsic() const {
  return (NodeType == ISD::INTRINSIC_W_CHAIN ||
          NodeType == ISD::INTRINSIC_VOID) &&
         SDNodeBits.IsMemIntrinsic;
}

/// Test if this node is a strict floating point pseudo-op.
bool isStrictFPOpcode() {
  switch (NodeType) {
    default:
      return false;
    case ISD::STRICT_FP16_TO_FP:
    case ISD::STRICT_FP_TO_FP16:
664#define DAG_INSTRUCTION(NAME, NARG, ROUND_MODE, INTRINSIC, DAGN)               \
    case ISD::STRICT_##DAGN:
666#include "llvm/IR/ConstrainedOps.def"
      return true;
  }
}

/// Test if this node has a post-isel opcode, directly
/// corresponding to a MachineInstr opcode.
bool isMachineOpcode() const { return NodeType < 0; }

/// This may only be called if isMachineOpcode returns
/// true. It returns the MachineInstr opcode value that the node's opcode
/// corresponds to.
unsigned getMachineOpcode() const {
  assert(isMachineOpcode() && "Not a MachineInstr opcode!")((void)0);
  return ~NodeType;
}

bool getHasDebugValue() const { return SDNodeBits.HasDebugValue; }
void setHasDebugValue(bool b) { SDNodeBits.HasDebugValue = b; }

bool isDivergent() const { return SDNodeBits.IsDivergent; }

/// Return true if there are no uses of this node.
bool use_empty() const { return UseList == nullptr; }

/// Return true if there is exactly one use of this node.
bool hasOneUse() const { return hasSingleElement(uses()); }

/// Return the number of uses of this node. This method takes
/// time proportional to the number of uses.
size_t use_size() const { return std::distance(use_begin(), use_end()); }

/// Return the unique node id.
int getNodeId() const { return NodeId; }

/// Set unique node id.
void setNodeId(int Id) { NodeId = Id; }

/// Return the node ordering.
unsigned getIROrder() const { return IROrder; }

/// Set the node ordering.
void setIROrder(unsigned Order) { IROrder = Order; }

/// Return the source location info.
const DebugLoc &getDebugLoc() const { return debugLoc; }

/// Set source location info.  Try to avoid this, putting
/// it in the constructor is preferable.
void setDebugLoc(DebugLoc dl) { debugLoc = std::move(dl); }

/// This class provides iterator support for SDUse
/// operands that use a specific SDNode.
class use_iterator {
  friend class SDNode;

  SDUse *Op = nullptr;

  explicit use_iterator(SDUse *op) : Op(op) {}

public:
  using iterator_category = std::forward_iterator_tag;
  using value_type = SDUse;
  using difference_type = std::ptrdiff_t;
  using pointer = value_type *;
  using reference = value_type &;

  use_iterator() = default;
  use_iterator(const use_iterator &I) : Op(I.Op) {}

  bool operator==(const use_iterator &x) const {
    return Op == x.Op;
  }
  bool operator!=(const use_iterator &x) const {
    return !operator==(x);
  }

  /// Return true if this iterator is at the end of uses list.
  bool atEnd() const { return Op == nullptr; }

  // Iterator traversal: forward iteration only.
  use_iterator &operator++() {          // Preincrement
    assert(Op && "Cannot increment end iterator!")((void)0);
    Op = Op->getNext();
    return *this;
  }

  use_iterator operator++(int) {        // Postincrement
    use_iterator tmp = *this; ++*this; return tmp;
  }

  /// Retrieve a pointer to the current user node.
  SDNode *operator*() const {
    assert(Op && "Cannot dereference end iterator!")((void)0);
    return Op->getUser();
  }

  SDNode *operator->() const { return operator*(); }

  SDUse &getUse() const { return *Op; }

  /// Retrieve the operand # of this use in its user.
  unsigned getOperandNo() const {
    assert(Op && "Cannot dereference end iterator!")((void)0);
    return (unsigned)(Op - Op->getUser()->OperandList);
  }
};

/// Provide iteration support to walk over all uses of an SDNode.
use_iterator use_begin() const {
  return use_iterator(UseList);
}

static use_iterator use_end() { return use_iterator(nullptr); }

inline iterator_range<use_iterator> uses() {
  return make_range(use_begin(), use_end());
}
inline iterator_range<use_iterator> uses() const {
  return make_range(use_begin(), use_end());
}

/// Return true if there are exactly NUSES uses of the indicated value.
/// This method ignores uses of other values defined by this operation.
bool hasNUsesOfValue(unsigned NUses, unsigned Value) const;

/// Return true if there are any use of the indicated value.
/// This method ignores uses of other values defined by this operation.
bool hasAnyUseOfValue(unsigned Value) const;

/// Return true if this node is the only use of N.
bool isOnlyUserOf(const SDNode *N) const;

/// Return true if this node is an operand of N.
bool isOperandOf(const SDNode *N) const;

/// Return true if this node is a predecessor of N.
/// NOTE: Implemented on top of hasPredecessor and every bit as
/// expensive. Use carefully.
bool isPredecessorOf(const SDNode *N) const {
  return N->hasPredecessor(this);
}

/// Return true if N is a predecessor of this node.
/// N is either an operand of this node, or can be reached by recursively
/// traversing up the operands.
/// NOTE: This is an expensive method. Use it carefully.
bool hasPredecessor(const SDNode *N) const;

/// Returns true if N is a predecessor of any node in Worklist. This
/// helper keeps Visited and Worklist sets externally to allow unions
/// searches to be performed in parallel, caching of results across
/// queries and incremental addition to Worklist. Stops early if N is
/// found but will resume. Remember to clear Visited and Worklists
/// if DAG changes. MaxSteps gives a maximum number of nodes to visit before
/// giving up. The TopologicalPrune flag signals that positive NodeIds are
/// topologically ordered (Operands have strictly smaller node id) and search
/// can be pruned leveraging this.
static bool hasPredecessorHelper(const SDNode *N,
                                 SmallPtrSetImpl<const SDNode *> &Visited,
                                 SmallVectorImpl<const SDNode *> &Worklist,
                                 unsigned int MaxSteps = 0,
                                 bool TopologicalPrune = false) {
  SmallVector<const SDNode *, 8> DeferredNodes;
  if (Visited.count(N))
    return true;

  // Node Id's are assigned in three places: As a topological
  // ordering (> 0), during legalization (results in values set to
  // 0), new nodes (set to -1). If N has a topolgical id then we
  // know that all nodes with ids smaller than it cannot be
  // successors and we need not check them. Filter out all node
  // that can't be matches. We add them to the worklist before exit
  // in case of multiple calls. Note that during selection the topological id
  // may be violated if a node's predecessor is selected before it. We mark
  // this at selection negating the id of unselected successors and
  // restricting topological pruning to positive ids.

  int NId = N->getNodeId();
  // If we Invalidated the Id, reconstruct original NId.
  if (NId < -1)
    NId = -(NId + 1);

  bool Found = false;
  while (!Worklist.empty()) {
    const SDNode *M = Worklist.pop_back_val();
    int MId = M->getNodeId();
    if (TopologicalPrune && M->getOpcode() != ISD::TokenFactor && (NId > 0) &&
        (MId > 0) && (MId < NId)) {
      DeferredNodes.push_back(M);
      continue;
    }
    for (const SDValue &OpV : M->op_values()) {
      SDNode *Op = OpV.getNode();
      if (Visited.insert(Op).second)
        Worklist.push_back(Op);
      if (Op == N)
        Found = true;
    }
    if (Found)
      break;
    if (MaxSteps != 0 && Visited.size() >= MaxSteps)
      break;
  }
  // Push deferred nodes back on worklist.
  Worklist.append(DeferredNodes.begin(), DeferredNodes.end());
  // If we bailed early, conservatively return found.
  if (MaxSteps != 0 && Visited.size() >= MaxSteps)
    return true;
  return Found;
}

/// Return true if all the users of N are contained in Nodes.
/// NOTE: Requires at least one match, but doesn't require them all.
static bool areOnlyUsersOf(ArrayRef<const SDNode *> Nodes, const SDNode *N);

/// Return the number of values used by this operation.
unsigned getNumOperands() const { return NumOperands; }

/// Return the maximum number of operands that a SDNode can hold.
static constexpr size_t getMaxNumOperands() {
  return std::numeric_limits<decltype(SDNode::NumOperands)>::max();
}

/// Helper method returns the integer value of a ConstantSDNode operand.
inline uint64_t getConstantOperandVal(unsigned Num) const;

/// Helper method returns the APInt of a ConstantSDNode operand.
inline const APInt &getConstantOperandAPInt(unsigned Num) const;

const SDValue &getOperand(unsigned Num) const {
  assert(Num < NumOperands && "Invalid child # of SDNode!")((void)0);
  return OperandList[Num];
}

using op_iterator = SDUse *;

op_iterator op_begin() const { return OperandList; }
op_iterator op_end() const { return OperandList+NumOperands; }
ArrayRef<SDUse> ops() const { return makeArrayRef(op_begin(), op_end()); }

/// Iterator for directly iterating over the operand SDValue's.
struct value_op_iterator
    : iterator_adaptor_base<value_op_iterator, op_iterator,
                            std::random_access_iterator_tag, SDValue,
                            ptrdiff_t, value_op_iterator *,
                            value_op_iterator *> {
  explicit value_op_iterator(SDUse *U = nullptr)
    : iterator_adaptor_base(U) {}

  const SDValue &operator*() const { return I->get(); }
};

iterator_range<value_op_iterator> op_values() const {
  return make_range(value_op_iterator(op_begin()),
                    value_op_iterator(op_end()));
}

SDVTList getVTList() const {
  SDVTList X = { ValueList, NumValues };
  return X;
}

/// If this node has a glue operand, return the node
/// to which the glue operand points. Otherwise return NULL.
SDNode *getGluedNode() const {
  if (getNumOperands() != 0 &&
      getOperand(getNumOperands()-1).getValueType() == MVT::Glue)
    return getOperand(getNumOperands()-1).getNode();
  return nullptr;
}

/// If this node has a glue value with a user, return
/// the user (there is at most one). Otherwise return NULL.
SDNode *getGluedUser() const {
  for (use_iterator UI = use_begin(), UE = use_end(); UI != UE; ++UI)
    if (UI.getUse().get().getValueType() == MVT::Glue)
      return *UI;
  return nullptr;
}

SDNodeFlags getFlags() const { return Flags; }
void setFlags(SDNodeFlags NewFlags) { Flags = NewFlags; }

/// Clear any flags in this node that aren't also set in Flags.
/// If Flags is not in a defined state then this has no effect.
void intersectFlagsWith(const SDNodeFlags Flags);

/// Return the number of values defined/returned by this operator.
unsigned getNumValues() const { return NumValues; }

/// Return the type of a specified result.
EVT getValueType(unsigned ResNo) const {
  assert(ResNo < NumValues && "Illegal result number!")((void)0);
  return ValueList[ResNo];
}

/// Return the type of a specified result as a simple type.
MVT getSimpleValueType(unsigned ResNo) const {
  return getValueType(ResNo).getSimpleVT();
}

/// Returns MVT::getSizeInBits(getValueType(ResNo)).
///
/// If the value type is a scalable vector type, the scalable property will
/// be set and the runtime size will be a positive integer multiple of the
/// base size.
TypeSize getValueSizeInBits(unsigned ResNo) const {
  return getValueType(ResNo).getSizeInBits();
}

using value_iterator = const EVT *;

value_iterator value_begin() const { return ValueList; }
value_iterator value_end() const { return ValueList+NumValues; }
iterator_range<value_iterator> values() const {
  return llvm::make_range(value_begin(), value_end());
}

/// Return the opcode of this operation for printing.
std::string getOperationName(const SelectionDAG *G = nullptr) const;
static const char* getIndexedModeName(ISD::MemIndexedMode AM);
void print_types(raw_ostream &OS, const SelectionDAG *G) const;
void print_details(raw_ostream &OS, const SelectionDAG *G) const;
void print(raw_ostream &OS, const SelectionDAG *G = nullptr) const;
void printr(raw_ostream &OS, const SelectionDAG *G = nullptr) const;

/// Print a SelectionDAG node and all children down to
/// the leaves.  The given SelectionDAG allows target-specific nodes
/// to be printed in human-readable form.  Unlike printr, this will
/// print the whole DAG, including children that appear multiple
/// times.
///
void printrFull(raw_ostream &O, const SelectionDAG *G = nullptr) const;

/// Print a SelectionDAG node and children up to
/// depth "depth."  The given SelectionDAG allows target-specific
/// nodes to be printed in human-readable form.  Unlike printr, this
/// will print children that appear multiple times wherever they are
/// used.
///
void printrWithDepth(raw_ostream &O, const SelectionDAG *G = nullptr,
                     unsigned depth = 100) const;

/// Dump this node, for debugging.
void dump() const;

/// Dump (recursively) this node and its use-def subgraph.
void dumpr() const;

/// Dump this node, for debugging.
/// The given SelectionDAG allows target-specific nodes to be printed
/// in human-readable form.
void dump(const SelectionDAG *G) const;

/// Dump (recursively) this node and its use-def subgraph.
/// The given SelectionDAG allows target-specific nodes to be printed
/// in human-readable form.
void dumpr(const SelectionDAG *G) const;

/// printrFull to dbgs().  The given SelectionDAG allows
/// target-specific nodes to be printed in human-readable form.
/// Unlike dumpr, this will print the whole DAG, including children
/// that appear multiple times.
void dumprFull(const SelectionDAG *G = nullptr) const;

/// printrWithDepth to dbgs().  The given
/// SelectionDAG allows target-specific nodes to be printed in
/// human-readable form.  Unlike dumpr, this will print children
/// that appear multiple times wherever they are used.
///
void dumprWithDepth(const SelectionDAG *G = nullptr,
                    unsigned depth = 100) const;

/// Gather unique data for the node.
void Profile(FoldingSetNodeID &ID) const;

/// This method should only be used by the SDUse class.
void addUse(SDUse &U) { U.addToList(&UseList); }

1046protected:
static SDVTList getSDVTList(EVT VT) {
  SDVTList Ret = { getValueTypeList(VT), 1 };
  return Ret;
}

/// Create an SDNode.
///
/// SDNodes are created without any operands, and never own the operand
/// storage. To add operands, see SelectionDAG::createOperands.
SDNode(unsigned Opc, unsigned Order, DebugLoc dl, SDVTList VTs)
    : NodeType(Opc), ValueList(VTs.VTs), NumValues(VTs.NumVTs),
      IROrder(Order), debugLoc(std::move(dl)) {
  memset(&RawSDNodeBits, 0, sizeof(RawSDNodeBits));
  assert(debugLoc.hasTrivialDestructor() && "Expected trivial destructor")((void)0);
  assert(NumValues == VTs.NumVTs &&((void)0)
         "NumValues wasn't wide enough for its operands!")((void)0);
}

/// Release the operands and set this node to have zero operands.
void DropOperands();
1067};

1069/// Wrapper class for IR location info (IR ordering and DebugLoc) to be passed
1070/// into SDNode creation functions.
1071/// When an SDNode is created from the DAGBuilder, the DebugLoc is extracted
1072/// from the original Instruction, and IROrder is the ordinal position of
1073/// the instruction.
1074/// When an SDNode is created after the DAG is being built, both DebugLoc and
1075/// the IROrder are propagated from the original SDNode.
1076/// So SDLoc class provides two constructors besides the default one, one to
1077/// be used by the DAGBuilder, the other to be used by others.
1078class SDLoc {
1079private:
DebugLoc DL;
int IROrder = 0;

1083public:
SDLoc() = default;
SDLoc(const SDNode *N) : DL(N->getDebugLoc()), IROrder(N->getIROrder()) {}
SDLoc(const SDValue V) : SDLoc(V.getNode()) {}
SDLoc(const Instruction *I, int Order) : IROrder(Order) {
  assert(Order >= 0 && "bad IROrder")((void)0);
  if (I)
    DL = I->getDebugLoc();
}

unsigned getIROrder() const { return IROrder; }
const DebugLoc &getDebugLoc() const { return DL; }
1095};

1097// Define inline functions from the SDValue class.

1099inline SDValue::SDValue(SDNode *node, unsigned resno)
  : Node(node), ResNo(resno) {
// Explicitly check for !ResNo to avoid use-after-free, because there are
// callers that use SDValue(N, 0) with a deleted N to indicate successful
// combines.
assert((!Node || !ResNo || ResNo < Node->getNumValues()) &&((void)0)
       "Invalid result number for the given node!")((void)0);
assert(ResNo < -2U && "Cannot use result numbers reserved for DenseMaps.")((void)0);
1107}

1109inline unsigned SDValue::getOpcode() const {
return Node->getOpcode();
1111}

1113inline EVT SDValue::getValueType() const {
return Node->getValueType(ResNo);
11
←
Called C++ object pointer is null
1115}

1117inline unsigned SDValue::getNumOperands() const {
return Node->getNumOperands();
1119}

1121inline const SDValue &SDValue::getOperand(unsigned i) const {
return Node->getOperand(i);
1123}

1125inline uint64_t SDValue::getConstantOperandVal(unsigned i) const {
return Node->getConstantOperandVal(i);
1127}

1129inline const APInt &SDValue::getConstantOperandAPInt(unsigned i) const {
return Node->getConstantOperandAPInt(i);
1131}

1133inline bool SDValue::isTargetOpcode() const {
return Node->isTargetOpcode();
1135}

1137inline bool SDValue::isTargetMemoryOpcode() const {
return Node->isTargetMemoryOpcode();
1139}

1141inline bool SDValue::isMachineOpcode() const {
return Node->isMachineOpcode();
1143}

1145inline unsigned SDValue::getMachineOpcode() const {
return Node->getMachineOpcode();
1147}

1149inline bool SDValue::isUndef() const {
return Node->isUndef();
1151}

1153inline bool SDValue::use_empty() const {
return !Node->hasAnyUseOfValue(ResNo);
1155}

1157inline bool SDValue::hasOneUse() const {
return Node->hasNUsesOfValue(1, ResNo);
1159}

1161inline const DebugLoc &SDValue::getDebugLoc() const {
return Node->getDebugLoc();
1163}

1165inline void SDValue::dump() const {
return Node->dump();
1167}

1169inline void SDValue::dump(const SelectionDAG *G) const {
return Node->dump(G);
1171}

1173inline void SDValue::dumpr() const {
return Node->dumpr();
1175}

1177inline void SDValue::dumpr(const SelectionDAG *G) const {
return Node->dumpr(G);
1179}

1181// Define inline functions from the SDUse class.

1183inline void SDUse::set(const SDValue &V) {
if (Val.getNode()) removeFromList();
Val = V;
if (V.getNode()) V.getNode()->addUse(*this);
1187}

1189inline void SDUse::setInitial(const SDValue &V) {
Val = V;
V.getNode()->addUse(*this);
1192}

1194inline void SDUse::setNode(SDNode *N) {
if (Val.getNode()) removeFromList();
Val.setNode(N);
if (N) N->addUse(*this);
1198}

1200/// This class is used to form a handle around another node that
1201/// is persistent and is updated across invocations of replaceAllUsesWith on its
1202/// operand.  This node should be directly created by end-users and not added to
1203/// the AllNodes list.
1204class HandleSDNode : public SDNode {
SDUse Op;

1207public:
explicit HandleSDNode(SDValue X)
  : SDNode(ISD::HANDLENODE, 0, DebugLoc(), getSDVTList(MVT::Other)) {
  // HandleSDNodes are never inserted into the DAG, so they won't be
  // auto-numbered. Use ID 65535 as a sentinel.
  PersistentId = 0xffff;

  // Manually set up the operand list. This node type is special in that it's
  // always stack allocated and SelectionDAG does not manage its operands.
  // TODO: This should either (a) not be in the SDNode hierarchy, or (b) not
  // be so special.
  Op.setUser(this);
  Op.setInitial(X);
  NumOperands = 1;
  OperandList = &Op;
}
~HandleSDNode();

const SDValue &getValue() const { return Op; }
1226};

1228class AddrSpaceCastSDNode : public SDNode {
1229private:
unsigned SrcAddrSpace;
unsigned DestAddrSpace;

1233public:
AddrSpaceCastSDNode(unsigned Order, const DebugLoc &dl, EVT VT,
                    unsigned SrcAS, unsigned DestAS);

unsigned getSrcAddressSpace() const { return SrcAddrSpace; }
unsigned getDestAddressSpace() const { return DestAddrSpace; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::ADDRSPACECAST;
}
1243};

1245/// This is an abstract virtual class for memory operations.
1246class MemSDNode : public SDNode {
1247private:
// VT of in-memory value.
EVT MemoryVT;

1251protected:
/// Memory reference information.
MachineMemOperand *MMO;

1255public:
MemSDNode(unsigned Opc, unsigned Order, const DebugLoc &dl, SDVTList VTs,
          EVT memvt, MachineMemOperand *MMO);

bool readMem() const { return MMO->isLoad(); }
bool writeMem() const { return MMO->isStore(); }

/// Returns alignment and volatility of the memory access
Align getOriginalAlign() const { return MMO->getBaseAlign(); }
Align getAlign() const { return MMO->getAlign(); }
// FIXME: Remove once transition to getAlign is over.
unsigned getAlignment() const { return MMO->getAlign().value(); }

/// Return the SubclassData value, without HasDebugValue. This contains an
/// encoding of the volatile flag, as well as bits used by subclasses. This
/// function should only be used to compute a FoldingSetNodeID value.
/// The HasDebugValue bit is masked out because CSE map needs to match
/// nodes with debug info with nodes without debug info. Same is about
/// isDivergent bit.
unsigned getRawSubclassData() const {
  uint16_t Data;
  union {
    char RawSDNodeBits[sizeof(uint16_t)];
    SDNodeBitfields SDNodeBits;
  };
  memcpy(&RawSDNodeBits, &this->RawSDNodeBits, sizeof(this->RawSDNodeBits));
  SDNodeBits.HasDebugValue = 0;
  SDNodeBits.IsDivergent = false;
  memcpy(&Data, &RawSDNodeBits, sizeof(RawSDNodeBits));
  return Data;
}

bool isVolatile() const { return MemSDNodeBits.IsVolatile; }
bool isNonTemporal() const { return MemSDNodeBits.IsNonTemporal; }
bool isDereferenceable() const { return MemSDNodeBits.IsDereferenceable; }
bool isInvariant() const { return MemSDNodeBits.IsInvariant; }

// Returns the offset from the location of the access.
int64_t getSrcValueOffset() const { return MMO->getOffset(); }

/// Returns the AA info that describes the dereference.
AAMDNodes getAAInfo() const { return MMO->getAAInfo(); }

/// Returns the Ranges that describes the dereference.
const MDNode *getRanges() const { return MMO->getRanges(); }

/// Returns the synchronization scope ID for this memory operation.
SyncScope::ID getSyncScopeID() const { return MMO->getSyncScopeID(); }

/// Return the atomic ordering requirements for this memory operation. For
/// cmpxchg atomic operations, return the atomic ordering requirements when
/// store occurs.
AtomicOrdering getSuccessOrdering() const {
  return MMO->getSuccessOrdering();
}

/// Return a single atomic ordering that is at least as strong as both the
/// success and failure orderings for an atomic operation.  (For operations
/// other than cmpxchg, this is equivalent to getSuccessOrdering().)
AtomicOrdering getMergedOrdering() const { return MMO->getMergedOrdering(); }

/// Return true if the memory operation ordering is Unordered or higher.
bool isAtomic() const { return MMO->isAtomic(); }

/// Returns true if the memory operation doesn't imply any ordering
/// constraints on surrounding memory operations beyond the normal memory
/// aliasing rules.
bool isUnordered() const { return MMO->isUnordered(); }

/// Returns true if the memory operation is neither atomic or volatile.
bool isSimple() const { return !isAtomic() && !isVolatile(); }

/// Return the type of the in-memory value.
EVT getMemoryVT() const { return MemoryVT; }

/// Return a MachineMemOperand object describing the memory
/// reference performed by operation.
MachineMemOperand *getMemOperand() const { return MMO; }

const MachinePointerInfo &getPointerInfo() const {
  return MMO->getPointerInfo();
}

/// Return the address space for the associated pointer
unsigned getAddressSpace() const {
  return getPointerInfo().getAddrSpace();
}

/// Update this MemSDNode's MachineMemOperand information
/// to reflect the alignment of NewMMO, if it has a greater alignment.
/// This must only be used when the new alignment applies to all users of
/// this MachineMemOperand.
void refineAlignment(const MachineMemOperand *NewMMO) {
  MMO->refineAlignment(NewMMO);
}

const SDValue &getChain() const { return getOperand(0); }

const SDValue &getBasePtr() const {
  switch (getOpcode()) {
  case ISD::STORE:
  case ISD::MSTORE:
    return getOperand(2);
  case ISD::MGATHER:
  case ISD::MSCATTER:
    return getOperand(3);
  default:
    return getOperand(1);
  }
}

// Methods to support isa and dyn_cast
static bool classof(const SDNode *N) {
  // For some targets, we lower some target intrinsics to a MemIntrinsicNode
  // with either an intrinsic or a target opcode.
  switch (N->getOpcode()) {
  case ISD::LOAD:
  case ISD::STORE:
  case ISD::PREFETCH:
  case ISD::ATOMIC_CMP_SWAP:
  case ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS:
  case ISD::ATOMIC_SWAP:
  case ISD::ATOMIC_LOAD_ADD:
  case ISD::ATOMIC_LOAD_SUB:
  case ISD::ATOMIC_LOAD_AND:
  case ISD::ATOMIC_LOAD_CLR:
  case ISD::ATOMIC_LOAD_OR:
  case ISD::ATOMIC_LOAD_XOR:
  case ISD::ATOMIC_LOAD_NAND:
  case ISD::ATOMIC_LOAD_MIN:
  case ISD::ATOMIC_LOAD_MAX:
  case ISD::ATOMIC_LOAD_UMIN:
  case ISD::ATOMIC_LOAD_UMAX:
  case ISD::ATOMIC_LOAD_FADD:
  case ISD::ATOMIC_LOAD_FSUB:
  case ISD::ATOMIC_LOAD:
  case ISD::ATOMIC_STORE:
  case ISD::MLOAD:
  case ISD::MSTORE:
  case ISD::MGATHER:
  case ISD::MSCATTER:
    return true;
  default:
    return N->isMemIntrinsic() || N->isTargetMemoryOpcode();
  }
}
1401};

1403/// This is an SDNode representing atomic operations.
1404class AtomicSDNode : public MemSDNode {
1405public:
AtomicSDNode(unsigned Opc, unsigned Order, const DebugLoc &dl, SDVTList VTL,
             EVT MemVT, MachineMemOperand *MMO)
  : MemSDNode(Opc, Order, dl, VTL, MemVT, MMO) {
  assert(((Opc != ISD::ATOMIC_LOAD && Opc != ISD::ATOMIC_STORE) ||((void)0)
          MMO->isAtomic()) && "then why are we using an AtomicSDNode?")((void)0);
}

const SDValue &getBasePtr() const { return getOperand(1); }
const SDValue &getVal() const { return getOperand(2); }

/// Returns true if this SDNode represents cmpxchg atomic operation, false
/// otherwise.
bool isCompareAndSwap() const {
  unsigned Op = getOpcode();
  return Op == ISD::ATOMIC_CMP_SWAP ||
         Op == ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS;
}

/// For cmpxchg atomic operations, return the atomic ordering requirements
/// when store does not occur.
AtomicOrdering getFailureOrdering() const {
  assert(isCompareAndSwap() && "Must be cmpxchg operation")((void)0);
  return MMO->getFailureOrdering();
}

// Methods to support isa and dyn_cast
static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::ATOMIC_CMP_SWAP     ||
         N->getOpcode() == ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS ||
         N->getOpcode() == ISD::ATOMIC_SWAP         ||
         N->getOpcode() == ISD::ATOMIC_LOAD_ADD     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_SUB     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_AND     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_CLR     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_OR      ||
         N->getOpcode() == ISD::ATOMIC_LOAD_XOR     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_NAND    ||
         N->getOpcode() == ISD::ATOMIC_LOAD_MIN     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_MAX     ||
         N->getOpcode() == ISD::ATOMIC_LOAD_UMIN    ||
         N->getOpcode() == ISD::ATOMIC_LOAD_UMAX    ||
         N->getOpcode() == ISD::ATOMIC_LOAD_FADD    ||
         N->getOpcode() == ISD::ATOMIC_LOAD_FSUB    ||
         N->getOpcode() == ISD::ATOMIC_LOAD         ||
         N->getOpcode() == ISD::ATOMIC_STORE;
}
1452};

1454/// This SDNode is used for target intrinsics that touch
1455/// memory and need an associated MachineMemOperand. Its opcode may be
1456/// INTRINSIC_VOID, INTRINSIC_W_CHAIN, PREFETCH, or a target-specific opcode
1457/// with a value not less than FIRST_TARGET_MEMORY_OPCODE.
1458class MemIntrinsicSDNode : public MemSDNode {
1459public:
MemIntrinsicSDNode(unsigned Opc, unsigned Order, const DebugLoc &dl,
                   SDVTList VTs, EVT MemoryVT, MachineMemOperand *MMO)
    : MemSDNode(Opc, Order, dl, VTs, MemoryVT, MMO) {
  SDNodeBits.IsMemIntrinsic = true;
}

// Methods to support isa and dyn_cast
static bool classof(const SDNode *N) {
  // We lower some target intrinsics to their target opcode
  // early a node with a target opcode can be of this class
  return N->isMemIntrinsic()             ||
         N->getOpcode() == ISD::PREFETCH ||
         N->isTargetMemoryOpcode();
}
1474};

1476/// This SDNode is used to implement the code generator
1477/// support for the llvm IR shufflevector instruction.  It combines elements
1478/// from two input vectors into a new input vector, with the selection and
1479/// ordering of elements determined by an array of integers, referred to as
1480/// the shuffle mask.  For input vectors of width N, mask indices of 0..N-1
1481/// refer to elements from the LHS input, and indices from N to 2N-1 the RHS.
1482/// An index of -1 is treated as undef, such that the code generator may put
1483/// any value in the corresponding element of the result.
1484class ShuffleVectorSDNode : public SDNode {
// The memory for Mask is owned by the SelectionDAG's OperandAllocator, and
// is freed when the SelectionDAG object is destroyed.
const int *Mask;

1489protected:
friend class SelectionDAG;

ShuffleVectorSDNode(EVT VT, unsigned Order, const DebugLoc &dl, const int *M)
    : SDNode(ISD::VECTOR_SHUFFLE, Order, dl, getSDVTList(VT)), Mask(M) {}

1495public:
ArrayRef<int> getMask() const {
  EVT VT = getValueType(0);
  return makeArrayRef(Mask, VT.getVectorNumElements());
}

int getMaskElt(unsigned Idx) const {
  assert(Idx < getValueType(0).getVectorNumElements() && "Idx out of range!")((void)0);
  return Mask[Idx];
}

bool isSplat() const { return isSplatMask(Mask, getValueType(0)); }

int getSplatIndex() const {
  assert(isSplat() && "Cannot get splat index for non-splat!")((void)0);
  EVT VT = getValueType(0);
  for (unsigned i = 0, e = VT.getVectorNumElements(); i != e; ++i)
    if (Mask[i] >= 0)
      return Mask[i];

  // We can choose any index value here and be correct because all elements
  // are undefined. Return 0 for better potential for callers to simplify.
  return 0;
}

static bool isSplatMask(const int *Mask, EVT VT);

/// Change values in a shuffle permute mask assuming
/// the two vector operands have swapped position.
static void commuteMask(MutableArrayRef<int> Mask) {
  unsigned NumElems = Mask.size();
  for (unsigned i = 0; i != NumElems; ++i) {
    int idx = Mask[i];
    if (idx < 0)
      continue;
    else if (idx < (int)NumElems)
      Mask[i] = idx + NumElems;
    else
      Mask[i] = idx - NumElems;
  }
}

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::VECTOR_SHUFFLE;
}
1540};

1542class ConstantSDNode : public SDNode {
friend class SelectionDAG;

const ConstantInt *Value;

ConstantSDNode(bool isTarget, bool isOpaque, const ConstantInt *val, EVT VT)
    : SDNode(isTarget ? ISD::TargetConstant : ISD::Constant, 0, DebugLoc(),
             getSDVTList(VT)),
      Value(val) {
  ConstantSDNodeBits.IsOpaque = isOpaque;
}

1554public:
const ConstantInt *getConstantIntValue() const { return Value; }
const APInt &getAPIntValue() const { return Value->getValue(); }
uint64_t getZExtValue() const { return Value->getZExtValue(); }
int64_t getSExtValue() const { return Value->getSExtValue(); }
uint64_t getLimitedValue(uint64_t Limit = UINT64_MAX0xffffffffffffffffULL) {
  return Value->getLimitedValue(Limit);
}
MaybeAlign getMaybeAlignValue() const { return Value->getMaybeAlignValue(); }
Align getAlignValue() const { return Value->getAlignValue(); }

bool isOne() const { return Value->isOne(); }
bool isNullValue() const { return Value->isZero(); }
bool isAllOnesValue() const { return Value->isMinusOne(); }
bool isMaxSignedValue() const { return Value->isMaxValue(true); }
bool isMinSignedValue() const { return Value->isMinValue(true); }

bool isOpaque() const { return ConstantSDNodeBits.IsOpaque; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::Constant ||
         N->getOpcode() == ISD::TargetConstant;
}
1577};

1579uint64_t SDNode::getConstantOperandVal(unsigned Num) const {
return cast<ConstantSDNode>(getOperand(Num))->getZExtValue();
1581}

1583const APInt &SDNode::getConstantOperandAPInt(unsigned Num) const {
return cast<ConstantSDNode>(getOperand(Num))->getAPIntValue();
1585}

1587class ConstantFPSDNode : public SDNode {
friend class SelectionDAG;

const ConstantFP *Value;

ConstantFPSDNode(bool isTarget, const ConstantFP *val, EVT VT)
    : SDNode(isTarget ? ISD::TargetConstantFP : ISD::ConstantFP, 0,
             DebugLoc(), getSDVTList(VT)),
      Value(val) {}

1597public:
const APFloat& getValueAPF() const { return Value->getValueAPF(); }
const ConstantFP *getConstantFPValue() const { return Value; }

/// Return true if the value is positive or negative zero.
bool isZero() const { return Value->isZero(); }

/// Return true if the value is a NaN.
bool isNaN() const { return Value->isNaN(); }

/// Return true if the value is an infinity
bool isInfinity() const { return Value->isInfinity(); }

/// Return true if the value is negative.
bool isNegative() const { return Value->isNegative(); }

/// We don't rely on operator== working on double values, as
/// it returns true for things that are clearly not equal, like -0.0 and 0.0.
/// As such, this method can be used to do an exact bit-for-bit comparison of
/// two floating point values.

/// We leave the version with the double argument here because it's just so
/// convenient to write "2.0" and the like.  Without this function we'd
/// have to duplicate its logic everywhere it's called.
bool isExactlyValue(double V) const {
  return Value->getValueAPF().isExactlyValue(V);
}
bool isExactlyValue(const APFloat& V) const;

static bool isValueValidForType(EVT VT, const APFloat& Val);

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::ConstantFP ||
         N->getOpcode() == ISD::TargetConstantFP;
}
1632};

1634/// Returns true if \p V is a constant integer zero.
1635bool isNullConstant(SDValue V);

1637/// Returns true if \p V is an FP constant with a value of positive zero.
1638bool isNullFPConstant(SDValue V);

1640/// Returns true if \p V is an integer constant with all bits set.
1641bool isAllOnesConstant(SDValue V);

1643/// Returns true if \p V is a constant integer one.
1644bool isOneConstant(SDValue V);

1646/// Return the non-bitcasted source operand of \p V if it exists.
1647/// If \p V is not a bitcasted value, it is returned as-is.
1648SDValue peekThroughBitcasts(SDValue V);

1650/// Return the non-bitcasted and one-use source operand of \p V if it exists.
1651/// If \p V is not a bitcasted one-use value, it is returned as-is.
1652SDValue peekThroughOneUseBitcasts(SDValue V);

1654/// Return the non-extracted vector source operand of \p V if it exists.
1655/// If \p V is not an extracted subvector, it is returned as-is.
1656SDValue peekThroughExtractSubvectors(SDValue V);

1658/// Returns true if \p V is a bitwise not operation. Assumes that an all ones
1659/// constant is canonicalized to be operand 1.
1660bool isBitwiseNot(SDValue V, bool AllowUndefs = false);

1662/// Returns the SDNode if it is a constant splat BuildVector or constant int.
1663ConstantSDNode *isConstOrConstSplat(SDValue N, bool AllowUndefs = false,
                                  bool AllowTruncation = false);

1666/// Returns the SDNode if it is a demanded constant splat BuildVector or
1667/// constant int.
1668ConstantSDNode *isConstOrConstSplat(SDValue N, const APInt &DemandedElts,
                                  bool AllowUndefs = false,
                                  bool AllowTruncation = false);

1672/// Returns the SDNode if it is a constant splat BuildVector or constant float.
1673ConstantFPSDNode *isConstOrConstSplatFP(SDValue N, bool AllowUndefs = false);

1675/// Returns the SDNode if it is a demanded constant splat BuildVector or
1676/// constant float.
1677ConstantFPSDNode *isConstOrConstSplatFP(SDValue N, const APInt &DemandedElts,
                                      bool AllowUndefs = false);

1680/// Return true if the value is a constant 0 integer or a splatted vector of
1681/// a constant 0 integer (with no undefs by default).
1682/// Build vector implicit truncation is not an issue for null values.
1683bool isNullOrNullSplat(SDValue V, bool AllowUndefs = false);

1685/// Return true if the value is a constant 1 integer or a splatted vector of a
1686/// constant 1 integer (with no undefs).
1687/// Does not permit build vector implicit truncation.
1688bool isOneOrOneSplat(SDValue V, bool AllowUndefs = false);

1690/// Return true if the value is a constant -1 integer or a splatted vector of a
1691/// constant -1 integer (with no undefs).
1692/// Does not permit build vector implicit truncation.
1693bool isAllOnesOrAllOnesSplat(SDValue V, bool AllowUndefs = false);

1695/// Return true if \p V is either a integer or FP constant.
1696inline bool isIntOrFPConstant(SDValue V) {
return isa<ConstantSDNode>(V) || isa<ConstantFPSDNode>(V);
1698}

1700class GlobalAddressSDNode : public SDNode {
friend class SelectionDAG;

const GlobalValue *TheGlobal;
int64_t Offset;
unsigned TargetFlags;

GlobalAddressSDNode(unsigned Opc, unsigned Order, const DebugLoc &DL,
                    const GlobalValue *GA, EVT VT, int64_t o,
                    unsigned TF);

1711public:
const GlobalValue *getGlobal() const { return TheGlobal; }
int64_t getOffset() const { return Offset; }
unsigned getTargetFlags() const { return TargetFlags; }
// Return the address space this GlobalAddress belongs to.
unsigned getAddressSpace() const;

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::GlobalAddress ||
         N->getOpcode() == ISD::TargetGlobalAddress ||
         N->getOpcode() == ISD::GlobalTLSAddress ||
         N->getOpcode() == ISD::TargetGlobalTLSAddress;
}
1724};

1726class FrameIndexSDNode : public SDNode {
friend class SelectionDAG;

int FI;

FrameIndexSDNode(int fi, EVT VT, bool isTarg)
  : SDNode(isTarg ? ISD::TargetFrameIndex : ISD::FrameIndex,
    0, DebugLoc(), getSDVTList(VT)), FI(fi) {
}

1736public:
int getIndex() const { return FI; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::FrameIndex ||
         N->getOpcode() == ISD::TargetFrameIndex;
}
1743};

1745/// This SDNode is used for LIFETIME_START/LIFETIME_END values, which indicate
1746/// the offet and size that are started/ended in the underlying FrameIndex.
1747class LifetimeSDNode : public SDNode {
friend class SelectionDAG;
int64_t Size;
int64_t Offset; // -1 if offset is unknown.

LifetimeSDNode(unsigned Opcode, unsigned Order, const DebugLoc &dl,
               SDVTList VTs, int64_t Size, int64_t Offset)
    : SDNode(Opcode, Order, dl, VTs), Size(Size), Offset(Offset) {}
1755public:
int64_t getFrameIndex() const {
  return cast<FrameIndexSDNode>(getOperand(1))->getIndex();
}

bool hasOffset() const { return Offset >= 0; }
int64_t getOffset() const {
  assert(hasOffset() && "offset is unknown")((void)0);
  return Offset;
}
int64_t getSize() const {
  assert(hasOffset() && "offset is unknown")((void)0);
  return Size;
}

// Methods to support isa and dyn_cast
static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::LIFETIME_START ||
         N->getOpcode() == ISD::LIFETIME_END;
}
1775};

1777/// This SDNode is used for PSEUDO_PROBE values, which are the function guid and
1778/// the index of the basic block being probed. A pseudo probe serves as a place
1779/// holder and will be removed at the end of compilation. It does not have any
1780/// operand because we do not want the instruction selection to deal with any.
1781class PseudoProbeSDNode : public SDNode {
friend class SelectionDAG;
uint64_t Guid;
uint64_t Index;
uint32_t Attributes;

PseudoProbeSDNode(unsigned Opcode, unsigned Order, const DebugLoc &Dl,
                  SDVTList VTs, uint64_t Guid, uint64_t Index, uint32_t Attr)
    : SDNode(Opcode, Order, Dl, VTs), Guid(Guid), Index(Index),
      Attributes(Attr) {}

1792public:
uint64_t getGuid() const { return Guid; }
uint64_t getIndex() const { return Index; }
uint32_t getAttributes() const { return Attributes; }

// Methods to support isa and dyn_cast
static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::PSEUDO_PROBE;
}
1801};

1803class JumpTableSDNode : public SDNode {
friend class SelectionDAG;

int JTI;
unsigned TargetFlags;

JumpTableSDNode(int jti, EVT VT, bool isTarg, unsigned TF)
  : SDNode(isTarg ? ISD::TargetJumpTable : ISD::JumpTable,
    0, DebugLoc(), getSDVTList(VT)), JTI(jti), TargetFlags(TF) {
}

1814public:
int getIndex() const { return JTI; }
unsigned getTargetFlags() const { return TargetFlags; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::JumpTable ||
         N->getOpcode() == ISD::TargetJumpTable;
}
1822};

1824class ConstantPoolSDNode : public SDNode {
friend class SelectionDAG;

union {
  const Constant *ConstVal;
  MachineConstantPoolValue *MachineCPVal;
} Val;
int Offset;  // It's a MachineConstantPoolValue if top bit is set.
Align Alignment; // Minimum alignment requirement of CP.
unsigned TargetFlags;

ConstantPoolSDNode(bool isTarget, const Constant *c, EVT VT, int o,
                   Align Alignment, unsigned TF)
    : SDNode(isTarget ? ISD::TargetConstantPool : ISD::ConstantPool, 0,
             DebugLoc(), getSDVTList(VT)),
      Offset(o), Alignment(Alignment), TargetFlags(TF) {
  assert(Offset >= 0 && "Offset is too large")((void)0);
  Val.ConstVal = c;
}

ConstantPoolSDNode(bool isTarget, MachineConstantPoolValue *v, EVT VT, int o,
                   Align Alignment, unsigned TF)
    : SDNode(isTarget ? ISD::TargetConstantPool : ISD::ConstantPool, 0,
             DebugLoc(), getSDVTList(VT)),
      Offset(o), Alignment(Alignment), TargetFlags(TF) {
  assert(Offset >= 0 && "Offset is too large")((void)0);
  Val.MachineCPVal = v;
  Offset |= 1 << (sizeof(unsigned)*CHAR_BIT8-1);
}

1854public:
bool isMachineConstantPoolEntry() const {
  return Offset < 0;
}

const Constant *getConstVal() const {
  assert(!isMachineConstantPoolEntry() && "Wrong constantpool type")((void)0);
  return Val.ConstVal;
}

MachineConstantPoolValue *getMachineCPVal() const {
  assert(isMachineConstantPoolEntry() && "Wrong constantpool type")((void)0);
  return Val.MachineCPVal;
}

int getOffset() const {
  return Offset & ~(1 << (sizeof(unsigned)*CHAR_BIT8-1));
}

// Return the alignment of this constant pool object, which is either 0 (for
// default alignment) or the desired value.
Align getAlign() const { return Alignment; }
unsigned getTargetFlags() const { return TargetFlags; }

Type *getType() const;

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::ConstantPool ||
         N->getOpcode() == ISD::TargetConstantPool;
}
1884};

1886/// Completely target-dependent object reference.
1887class TargetIndexSDNode : public SDNode {
friend class SelectionDAG;

unsigned TargetFlags;
int Index;
int64_t Offset;

1894public:
TargetIndexSDNode(int Idx, EVT VT, int64_t Ofs, unsigned TF)
    : SDNode(ISD::TargetIndex, 0, DebugLoc(), getSDVTList(VT)),
      TargetFlags(TF), Index(Idx), Offset(Ofs) {}

unsigned getTargetFlags() const { return TargetFlags; }
int getIndex() const { return Index; }
int64_t getOffset() const { return Offset; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::TargetIndex;
}
1906};

1908class BasicBlockSDNode : public SDNode {
friend class SelectionDAG;

MachineBasicBlock *MBB;

/// Debug info is meaningful and potentially useful here, but we create
/// blocks out of order when they're jumped to, which makes it a bit
/// harder.  Let's see if we need it first.
explicit BasicBlockSDNode(MachineBasicBlock *mbb)
  : SDNode(ISD::BasicBlock, 0, DebugLoc(), getSDVTList(MVT::Other)), MBB(mbb)
{}

1920public:
MachineBasicBlock *getBasicBlock() const { return MBB; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::BasicBlock;
}
1926};

1928/// A "pseudo-class" with methods for operating on BUILD_VECTORs.
1929class BuildVectorSDNode : public SDNode {
1930public:
// These are constructed as SDNodes and then cast to BuildVectorSDNodes.
explicit BuildVectorSDNode() = delete;

/// Check if this is a constant splat, and if so, find the
/// smallest element size that splats the vector.  If MinSplatBits is
/// nonzero, the element size must be at least that large.  Note that the
/// splat element may be the entire vector (i.e., a one element vector).
/// Returns the splat element value in SplatValue.  Any undefined bits in
/// that value are zero, and the corresponding bits in the SplatUndef mask
/// are set.  The SplatBitSize value is set to the splat element size in
/// bits.  HasAnyUndefs is set to true if any bits in the vector are
/// undefined.  isBigEndian describes the endianness of the target.
bool isConstantSplat(APInt &SplatValue, APInt &SplatUndef,
                     unsigned &SplatBitSize, bool &HasAnyUndefs,
                     unsigned MinSplatBits = 0,
                     bool isBigEndian = false) const;

/// Returns the demanded splatted value or a null value if this is not a
/// splat.
///
/// The DemandedElts mask indicates the elements that must be in the splat.
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the vector width and set the bits where elements are undef.
SDValue getSplatValue(const APInt &DemandedElts,
                      BitVector *UndefElements = nullptr) const;

/// Returns the splatted value or a null value if this is not a splat.
///
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the vector width and set the bits where elements are undef.
SDValue getSplatValue(BitVector *UndefElements = nullptr) const;

/// Find the shortest repeating sequence of values in the build vector.
///
/// e.g. { u, X, u, X, u, u, X, u } -> { X }
///      { X, Y, u, Y, u, u, X, u } -> { X, Y }
///
/// Currently this must be a power-of-2 build vector.
/// The DemandedElts mask indicates the elements that must be present,
/// undemanded elements in Sequence may be null (SDValue()). If passed a
/// non-null UndefElements bitvector, it will resize it to match the original
/// vector width and set the bits where elements are undef. If result is
/// false, Sequence will be empty.
bool getRepeatedSequence(const APInt &DemandedElts,
                         SmallVectorImpl<SDValue> &Sequence,
                         BitVector *UndefElements = nullptr) const;

/// Find the shortest repeating sequence of values in the build vector.
///
/// e.g. { u, X, u, X, u, u, X, u } -> { X }
///      { X, Y, u, Y, u, u, X, u } -> { X, Y }
///
/// Currently this must be a power-of-2 build vector.
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the original vector width and set the bits where elements are undef.
/// If result is false, Sequence will be empty.
bool getRepeatedSequence(SmallVectorImpl<SDValue> &Sequence,
                         BitVector *UndefElements = nullptr) const;

/// Returns the demanded splatted constant or null if this is not a constant
/// splat.
///
/// The DemandedElts mask indicates the elements that must be in the splat.
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the vector width and set the bits where elements are undef.
ConstantSDNode *
getConstantSplatNode(const APInt &DemandedElts,
                     BitVector *UndefElements = nullptr) const;

/// Returns the splatted constant or null if this is not a constant
/// splat.
///
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the vector width and set the bits where elements are undef.
ConstantSDNode *
getConstantSplatNode(BitVector *UndefElements = nullptr) const;

/// Returns the demanded splatted constant FP or null if this is not a
/// constant FP splat.
///
/// The DemandedElts mask indicates the elements that must be in the splat.
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the vector width and set the bits where elements are undef.
ConstantFPSDNode *
getConstantFPSplatNode(const APInt &DemandedElts,
                       BitVector *UndefElements = nullptr) const;

/// Returns the splatted constant FP or null if this is not a constant
/// FP splat.
///
/// If passed a non-null UndefElements bitvector, it will resize it to match
/// the vector width and set the bits where elements are undef.
ConstantFPSDNode *
getConstantFPSplatNode(BitVector *UndefElements = nullptr) const;

/// If this is a constant FP splat and the splatted constant FP is an
/// exact power or 2, return the log base 2 integer value.  Otherwise,
/// return -1.
///
/// The BitWidth specifies the necessary bit precision.
int32_t getConstantFPSplatPow2ToLog2Int(BitVector *UndefElements,
                                        uint32_t BitWidth) const;

bool isConstant() const;

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::BUILD_VECTOR;
}
2039};

2041/// An SDNode that holds an arbitrary LLVM IR Value. This is
2042/// used when the SelectionDAG needs to make a simple reference to something
2043/// in the LLVM IR representation.
2044///
2045class SrcValueSDNode : public SDNode {
friend class SelectionDAG;

const Value *V;

/// Create a SrcValue for a general value.
explicit SrcValueSDNode(const Value *v)
  : SDNode(ISD::SRCVALUE, 0, DebugLoc(), getSDVTList(MVT::Other)), V(v) {}

2054public:
/// Return the contained Value.
const Value *getValue() const { return V; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::SRCVALUE;
}
2061};

2063class MDNodeSDNode : public SDNode {
friend class SelectionDAG;

const MDNode *MD;

explicit MDNodeSDNode(const MDNode *md)
: SDNode(ISD::MDNODE_SDNODE, 0, DebugLoc(), getSDVTList(MVT::Other)), MD(md)
{}

2072public:
const MDNode *getMD() const { return MD; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MDNODE_SDNODE;
}
2078};

2080class RegisterSDNode : public SDNode {
friend class SelectionDAG;

Register Reg;

RegisterSDNode(Register reg, EVT VT)
  : SDNode(ISD::Register, 0, DebugLoc(), getSDVTList(VT)), Reg(reg) {}

2088public:
Register getReg() const { return Reg; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::Register;
}
2094};

2096class RegisterMaskSDNode : public SDNode {
friend class SelectionDAG;

// The memory for RegMask is not owned by the node.
const uint32_t *RegMask;

RegisterMaskSDNode(const uint32_t *mask)
  : SDNode(ISD::RegisterMask, 0, DebugLoc(), getSDVTList(MVT::Untyped)),
    RegMask(mask) {}

2106public:
const uint32_t *getRegMask() const { return RegMask; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::RegisterMask;
}
2112};

2114class BlockAddressSDNode : public SDNode {
friend class SelectionDAG;

const BlockAddress *BA;
int64_t Offset;
unsigned TargetFlags;

BlockAddressSDNode(unsigned NodeTy, EVT VT, const BlockAddress *ba,
                   int64_t o, unsigned Flags)
  : SDNode(NodeTy, 0, DebugLoc(), getSDVTList(VT)),
           BA(ba), Offset(o), TargetFlags(Flags) {}

2126public:
const BlockAddress *getBlockAddress() const { return BA; }
int64_t getOffset() const { return Offset; }
unsigned getTargetFlags() const { return TargetFlags; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::BlockAddress ||
         N->getOpcode() == ISD::TargetBlockAddress;
}
2135};

2137class LabelSDNode : public SDNode {
friend class SelectionDAG;

MCSymbol *Label;

LabelSDNode(unsigned Opcode, unsigned Order, const DebugLoc &dl, MCSymbol *L)
    : SDNode(Opcode, Order, dl, getSDVTList(MVT::Other)), Label(L) {
  assert(LabelSDNode::classof(this) && "not a label opcode")((void)0);
}

2147public:
MCSymbol *getLabel() const { return Label; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::EH_LABEL ||
         N->getOpcode() == ISD::ANNOTATION_LABEL;
}
2154};

2156class ExternalSymbolSDNode : public SDNode {
friend class SelectionDAG;

const char *Symbol;
unsigned TargetFlags;

ExternalSymbolSDNode(bool isTarget, const char *Sym, unsigned TF, EVT VT)
    : SDNode(isTarget ? ISD::TargetExternalSymbol : ISD::ExternalSymbol, 0,
             DebugLoc(), getSDVTList(VT)),
      Symbol(Sym), TargetFlags(TF) {}

2167public:
const char *getSymbol() const { return Symbol; }
unsigned getTargetFlags() const { return TargetFlags; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::ExternalSymbol ||
         N->getOpcode() == ISD::TargetExternalSymbol;
}
2175};

2177class MCSymbolSDNode : public SDNode {
friend class SelectionDAG;

MCSymbol *Symbol;

MCSymbolSDNode(MCSymbol *Symbol, EVT VT)
    : SDNode(ISD::MCSymbol, 0, DebugLoc(), getSDVTList(VT)), Symbol(Symbol) {}

2185public:
MCSymbol *getMCSymbol() const { return Symbol; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MCSymbol;
}
2191};

2193class CondCodeSDNode : public SDNode {
friend class SelectionDAG;

ISD::CondCode Condition;

explicit CondCodeSDNode(ISD::CondCode Cond)
  : SDNode(ISD::CONDCODE, 0, DebugLoc(), getSDVTList(MVT::Other)),
    Condition(Cond) {}

2202public:
ISD::CondCode get() const { return Condition; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::CONDCODE;
}
2208};

2210/// This class is used to represent EVT's, which are used
2211/// to parameterize some operations.
2212class VTSDNode : public SDNode {
friend class SelectionDAG;

EVT ValueType;

explicit VTSDNode(EVT VT)
  : SDNode(ISD::VALUETYPE, 0, DebugLoc(), getSDVTList(MVT::Other)),
    ValueType(VT) {}

2221public:
EVT getVT() const { return ValueType; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::VALUETYPE;
}
2227};

2229/// Base class for LoadSDNode and StoreSDNode
2230class LSBaseSDNode : public MemSDNode {
2231public:
LSBaseSDNode(ISD::NodeType NodeTy, unsigned Order, const DebugLoc &dl,
             SDVTList VTs, ISD::MemIndexedMode AM, EVT MemVT,
             MachineMemOperand *MMO)
    : MemSDNode(NodeTy, Order, dl, VTs, MemVT, MMO) {
  LSBaseSDNodeBits.AddressingMode = AM;
  assert(getAddressingMode() == AM && "Value truncated")((void)0);
}

const SDValue &getOffset() const {
  return getOperand(getOpcode() == ISD::LOAD ? 2 : 3);
}

/// Return the addressing mode for this load or store:
/// unindexed, pre-inc, pre-dec, post-inc, or post-dec.
ISD::MemIndexedMode getAddressingMode() const {
  return static_cast<ISD::MemIndexedMode>(LSBaseSDNodeBits.AddressingMode);
}

/// Return true if this is a pre/post inc/dec load/store.
bool isIndexed() const { return getAddressingMode() != ISD::UNINDEXED; }

/// Return true if this is NOT a pre/post inc/dec load/store.
bool isUnindexed() const { return getAddressingMode() == ISD::UNINDEXED; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::LOAD ||
         N->getOpcode() == ISD::STORE;
}
2260};

2262/// This class is used to represent ISD::LOAD nodes.
2263class LoadSDNode : public LSBaseSDNode {
friend class SelectionDAG;

LoadSDNode(unsigned Order, const DebugLoc &dl, SDVTList VTs,
           ISD::MemIndexedMode AM, ISD::LoadExtType ETy, EVT MemVT,
           MachineMemOperand *MMO)
    : LSBaseSDNode(ISD::LOAD, Order, dl, VTs, AM, MemVT, MMO) {
  LoadSDNodeBits.ExtTy = ETy;
  assert(readMem() && "Load MachineMemOperand is not a load!")((void)0);
  assert(!writeMem() && "Load MachineMemOperand is a store!")((void)0);
}

2275public:
/// Return whether this is a plain node,
/// or one of the varieties of value-extending loads.
ISD::LoadExtType getExtensionType() const {
  return static_cast<ISD::LoadExtType>(LoadSDNodeBits.ExtTy);
}

const SDValue &getBasePtr() const { return getOperand(1); }
const SDValue &getOffset() const { return getOperand(2); }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::LOAD;
}
2288};

2290/// This class is used to represent ISD::STORE nodes.
2291class StoreSDNode : public LSBaseSDNode {
friend class SelectionDAG;

StoreSDNode(unsigned Order, const DebugLoc &dl, SDVTList VTs,
            ISD::MemIndexedMode AM, bool isTrunc, EVT MemVT,
            MachineMemOperand *MMO)
    : LSBaseSDNode(ISD::STORE, Order, dl, VTs, AM, MemVT, MMO) {
  StoreSDNodeBits.IsTruncating = isTrunc;
  assert(!readMem() && "Store MachineMemOperand is a load!")((void)0);
  assert(writeMem() && "Store MachineMemOperand is not a store!")((void)0);
}

2303public:
/// Return true if the op does a truncation before store.
/// For integers this is the same as doing a TRUNCATE and storing the result.
/// For floats, it is the same as doing an FP_ROUND and storing the result.
bool isTruncatingStore() const { return StoreSDNodeBits.IsTruncating; }
void setTruncatingStore(bool Truncating) {
  StoreSDNodeBits.IsTruncating = Truncating;
}

const SDValue &getValue() const { return getOperand(1); }
const SDValue &getBasePtr() const { return getOperand(2); }
const SDValue &getOffset() const { return getOperand(3); }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::STORE;
}
2319};

2321/// This base class is used to represent MLOAD and MSTORE nodes
2322class MaskedLoadStoreSDNode : public MemSDNode {
2323public:
friend class SelectionDAG;

MaskedLoadStoreSDNode(ISD::NodeType NodeTy, unsigned Order,
                      const DebugLoc &dl, SDVTList VTs,
                      ISD::MemIndexedMode AM, EVT MemVT,
                      MachineMemOperand *MMO)
    : MemSDNode(NodeTy, Order, dl, VTs, MemVT, MMO) {
  LSBaseSDNodeBits.AddressingMode = AM;
  assert(getAddressingMode() == AM && "Value truncated")((void)0);
}

// MaskedLoadSDNode (Chain, ptr, offset, mask, passthru)
// MaskedStoreSDNode (Chain, data, ptr, offset, mask)
// Mask is a vector of i1 elements
const SDValue &getOffset() const {
  return getOperand(getOpcode() == ISD::MLOAD ? 2 : 3);
}
const SDValue &getMask() const {
  return getOperand(getOpcode() == ISD::MLOAD ? 3 : 4);
}

/// Return the addressing mode for this load or store:
/// unindexed, pre-inc, pre-dec, post-inc, or post-dec.
ISD::MemIndexedMode getAddressingMode() const {
  return static_cast<ISD::MemIndexedMode>(LSBaseSDNodeBits.AddressingMode);
}

/// Return true if this is a pre/post inc/dec load/store.
bool isIndexed() const { return getAddressingMode() != ISD::UNINDEXED; }

/// Return true if this is NOT a pre/post inc/dec load/store.
bool isUnindexed() const { return getAddressingMode() == ISD::UNINDEXED; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MLOAD ||
         N->getOpcode() == ISD::MSTORE;
}
2361};

2363/// This class is used to represent an MLOAD node
2364class MaskedLoadSDNode : public MaskedLoadStoreSDNode {
2365public:
friend class SelectionDAG;

MaskedLoadSDNode(unsigned Order, const DebugLoc &dl, SDVTList VTs,
                 ISD::MemIndexedMode AM, ISD::LoadExtType ETy,
                 bool IsExpanding, EVT MemVT, MachineMemOperand *MMO)
    : MaskedLoadStoreSDNode(ISD::MLOAD, Order, dl, VTs, AM, MemVT, MMO) {
  LoadSDNodeBits.ExtTy = ETy;
  LoadSDNodeBits.IsExpanding = IsExpanding;
}

ISD::LoadExtType getExtensionType() const {
  return static_cast<ISD::LoadExtType>(LoadSDNodeBits.ExtTy);
}

const SDValue &getBasePtr() const { return getOperand(1); }
const SDValue &getOffset() const { return getOperand(2); }
const SDValue &getMask() const { return getOperand(3); }
const SDValue &getPassThru() const { return getOperand(4); }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MLOAD;
}

bool isExpandingLoad() const { return LoadSDNodeBits.IsExpanding; }
2390};

2392/// This class is used to represent an MSTORE node
2393class MaskedStoreSDNode : public MaskedLoadStoreSDNode {
2394public:
friend class SelectionDAG;

MaskedStoreSDNode(unsigned Order, const DebugLoc &dl, SDVTList VTs,
                  ISD::MemIndexedMode AM, bool isTrunc, bool isCompressing,
                  EVT MemVT, MachineMemOperand *MMO)
    : MaskedLoadStoreSDNode(ISD::MSTORE, Order, dl, VTs, AM, MemVT, MMO) {
  StoreSDNodeBits.IsTruncating = isTrunc;
  StoreSDNodeBits.IsCompressing = isCompressing;
}

/// Return true if the op does a truncation before store.
/// For integers this is the same as doing a TRUNCATE and storing the result.
/// For floats, it is the same as doing an FP_ROUND and storing the result.
bool isTruncatingStore() const { return StoreSDNodeBits.IsTruncating; }

/// Returns true if the op does a compression to the vector before storing.
/// The node contiguously stores the active elements (integers or floats)
/// in src (those with their respective bit set in writemask k) to unaligned
/// memory at base_addr.
bool isCompressingStore() const { return StoreSDNodeBits.IsCompressing; }

const SDValue &getValue() const { return getOperand(1); }
const SDValue &getBasePtr() const { return getOperand(2); }
const SDValue &getOffset() const { return getOperand(3); }
const SDValue &getMask() const { return getOperand(4); }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MSTORE;
}
2424};

2426/// This is a base class used to represent
2427/// MGATHER and MSCATTER nodes
2428///
2429class MaskedGatherScatterSDNode : public MemSDNode {
2430public:
friend class SelectionDAG;

MaskedGatherScatterSDNode(ISD::NodeType NodeTy, unsigned Order,
                          const DebugLoc &dl, SDVTList VTs, EVT MemVT,
                          MachineMemOperand *MMO, ISD::MemIndexType IndexType)
    : MemSDNode(NodeTy, Order, dl, VTs, MemVT, MMO) {
  LSBaseSDNodeBits.AddressingMode = IndexType;
  assert(getIndexType() == IndexType && "Value truncated")((void)0);
}

/// How is Index applied to BasePtr when computing addresses.
ISD::MemIndexType getIndexType() const {
  return static_cast<ISD::MemIndexType>(LSBaseSDNodeBits.AddressingMode);
}
void setIndexType(ISD::MemIndexType IndexType) {
  LSBaseSDNodeBits.AddressingMode = IndexType;
}
bool isIndexScaled() const {
  return (getIndexType() == ISD::SIGNED_SCALED) ||
         (getIndexType() == ISD::UNSIGNED_SCALED);
}
bool isIndexSigned() const {
  return (getIndexType() == ISD::SIGNED_SCALED) ||
         (getIndexType() == ISD::SIGNED_UNSCALED);
}

// In the both nodes address is Op1, mask is Op2:
// MaskedGatherSDNode  (Chain, passthru, mask, base, index, scale)
// MaskedScatterSDNode (Chain, value, mask, base, index, scale)
// Mask is a vector of i1 elements
const SDValue &getBasePtr() const { return getOperand(3); }
const SDValue &getIndex()   const { return getOperand(4); }
const SDValue &getMask()    const { return getOperand(2); }
const SDValue &getScale()   const { return getOperand(5); }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MGATHER ||
         N->getOpcode() == ISD::MSCATTER;
}
2470};

2472/// This class is used to represent an MGATHER node
2473///
2474class MaskedGatherSDNode : public MaskedGatherScatterSDNode {
2475public:
friend class SelectionDAG;

MaskedGatherSDNode(unsigned Order, const DebugLoc &dl, SDVTList VTs,
                   EVT MemVT, MachineMemOperand *MMO,
                   ISD::MemIndexType IndexType, ISD::LoadExtType ETy)
    : MaskedGatherScatterSDNode(ISD::MGATHER, Order, dl, VTs, MemVT, MMO,
                                IndexType) {
  LoadSDNodeBits.ExtTy = ETy;
}

const SDValue &getPassThru() const { return getOperand(1); }

ISD::LoadExtType getExtensionType() const {
  return ISD::LoadExtType(LoadSDNodeBits.ExtTy);
}

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MGATHER;
}
2495};

2497/// This class is used to represent an MSCATTER node
2498///
2499class MaskedScatterSDNode : public MaskedGatherScatterSDNode {
2500public:
friend class SelectionDAG;

MaskedScatterSDNode(unsigned Order, const DebugLoc &dl, SDVTList VTs,
                    EVT MemVT, MachineMemOperand *MMO,
                    ISD::MemIndexType IndexType, bool IsTrunc)
    : MaskedGatherScatterSDNode(ISD::MSCATTER, Order, dl, VTs, MemVT, MMO,
                                IndexType) {
  StoreSDNodeBits.IsTruncating = IsTrunc;
}

/// Return true if the op does a truncation before store.
/// For integers this is the same as doing a TRUNCATE and storing the result.
/// For floats, it is the same as doing an FP_ROUND and storing the result.
bool isTruncatingStore() const { return StoreSDNodeBits.IsTruncating; }

const SDValue &getValue() const { return getOperand(1); }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::MSCATTER;
}
2521};

2523/// An SDNode that represents everything that will be needed
2524/// to construct a MachineInstr. These nodes are created during the
2525/// instruction selection proper phase.
2526///
2527/// Note that the only supported way to set the `memoperands` is by calling the
2528/// `SelectionDAG::setNodeMemRefs` function as the memory management happens
2529/// inside the DAG rather than in the node.
2530class MachineSDNode : public SDNode {
2531private:
friend class SelectionDAG;

MachineSDNode(unsigned Opc, unsigned Order, const DebugLoc &DL, SDVTList VTs)
    : SDNode(Opc, Order, DL, VTs) {}

// We use a pointer union between a single `MachineMemOperand` pointer and
// a pointer to an array of `MachineMemOperand` pointers. This is null when
// the number of these is zero, the single pointer variant used when the
// number is one, and the array is used for larger numbers.
//
// The array is allocated via the `SelectionDAG`'s allocator and so will
// always live until the DAG is cleaned up and doesn't require ownership here.
//
// We can't use something simpler like `TinyPtrVector` here because `SDNode`
// subclasses aren't managed in a conforming C++ manner. See the comments on
// `SelectionDAG::MorphNodeTo` which details what all goes on, but the
// constraint here is that these don't manage memory with their constructor or
// destructor and can be initialized to a good state even if they start off
// uninitialized.
PointerUnion<MachineMemOperand *, MachineMemOperand **> MemRefs = {};

// Note that this could be folded into the above `MemRefs` member if doing so
// is advantageous at some point. We don't need to store this in most cases.
// However, at the moment this doesn't appear to make the allocation any
// smaller and makes the code somewhat simpler to read.
int NumMemRefs = 0;

2559public:
using mmo_iterator = ArrayRef<MachineMemOperand *>::const_iterator;

ArrayRef<MachineMemOperand *> memoperands() const {
  // Special case the common cases.
  if (NumMemRefs == 0)
    return {};
  if (NumMemRefs == 1)
    return makeArrayRef(MemRefs.getAddrOfPtr1(), 1);

  // Otherwise we have an actual array.
  return makeArrayRef(MemRefs.get<MachineMemOperand **>(), NumMemRefs);
}
mmo_iterator memoperands_begin() const { return memoperands().begin(); }
mmo_iterator memoperands_end() const { return memoperands().end(); }
bool memoperands_empty() const { return memoperands().empty(); }

/// Clear out the memory reference descriptor list.
void clearMemRefs() {
  MemRefs = nullptr;
  NumMemRefs = 0;
}

static bool classof(const SDNode *N) {
  return N->isMachineOpcode();
}
2585};

2587/// An SDNode that records if a register contains a value that is guaranteed to
2588/// be aligned accordingly.
2589class AssertAlignSDNode : public SDNode {
Align Alignment;

2592public:
AssertAlignSDNode(unsigned Order, const DebugLoc &DL, EVT VT, Align A)
    : SDNode(ISD::AssertAlign, Order, DL, getSDVTList(VT)), Alignment(A) {}

Align getAlign() const { return Alignment; }

static bool classof(const SDNode *N) {
  return N->getOpcode() == ISD::AssertAlign;
}
2601};

2603class SDNodeIterator {
const SDNode *Node;
unsigned Operand;

SDNodeIterator(const SDNode *N, unsigned Op) : Node(N), Operand(Op) {}

2609public:
using iterator_category = std::forward_iterator_tag;
using value_type = SDNode;
using difference_type = std::ptrdiff_t;
using pointer = value_type *;
using reference = value_type &;

bool operator==(const SDNodeIterator& x) const {
  return Operand == x.Operand;
}
bool operator!=(const SDNodeIterator& x) const { return !operator==(x); }

pointer operator*() const {
  return Node->getOperand(Operand).getNode();
}
pointer operator->() const { return operator*(); }

SDNodeIterator& operator++() {                // Preincrement
  ++Operand;
  return *this;
}
SDNodeIterator operator++(int) { // Postincrement
  SDNodeIterator tmp = *this; ++*this; return tmp;
}
size_t operator-(SDNodeIterator Other) const {
  assert(Node == Other.Node &&((void)0)
         "Cannot compare iterators of two different nodes!")((void)0);
  return Operand - Other.Operand;
}

static SDNodeIterator begin(const SDNode *N) { return SDNodeIterator(N, 0); }
static SDNodeIterator end  (const SDNode *N) {
  return SDNodeIterator(N, N->getNumOperands());
}

unsigned getOperand() const { return Operand; }
const SDNode *getNode() const { return Node; }
2646};

2648template <> struct GraphTraits<SDNode*> {
using NodeRef = SDNode *;
using ChildIteratorType = SDNodeIterator;

static NodeRef getEntryNode(SDNode *N) { return N; }

static ChildIteratorType child_begin(NodeRef N) {
  return SDNodeIterator::begin(N);
}

static ChildIteratorType child_end(NodeRef N) {
  return SDNodeIterator::end(N);
}
2661};

2663/// A representation of the largest SDNode, for use in sizeof().
2664///
2665/// This needs to be a union because the largest node differs on 32 bit systems
2666/// with 4 and 8 byte pointer alignment, respectively.
2667using LargestSDNode = AlignedCharArrayUnion<AtomicSDNode, TargetIndexSDNode,
                                          BlockAddressSDNode,
                                          GlobalAddressSDNode,
                                          PseudoProbeSDNode>;

2672/// The SDNode class with the greatest alignment requirement.
2673using MostAlignedSDNode = GlobalAddressSDNode;

2675namespace ISD {

/// Returns true if the specified node is a non-extending and unindexed load.
inline bool isNormalLoad(const SDNode *N) {
  const LoadSDNode *Ld = dyn_cast<LoadSDNode>(N);
  return Ld && Ld->getExtensionType() == ISD::NON_EXTLOAD &&
    Ld->getAddressingMode() == ISD::UNINDEXED;
}

/// Returns true if the specified node is a non-extending load.
inline bool isNON_EXTLoad(const SDNode *N) {
  return isa<LoadSDNode>(N) &&
    cast<LoadSDNode>(N)->getExtensionType() == ISD::NON_EXTLOAD;
}

/// Returns true if the specified node is a EXTLOAD.
inline bool isEXTLoad(const SDNode *N) {
  return isa<LoadSDNode>(N) &&
    cast<LoadSDNode>(N)->getExtensionType() == ISD::EXTLOAD;
}

/// Returns true if the specified node is a SEXTLOAD.
inline bool isSEXTLoad(const SDNode *N) {
  return isa<LoadSDNode>(N) &&
    cast<LoadSDNode>(N)->getExtensionType() == ISD::SEXTLOAD;
}

/// Returns true if the specified node is a ZEXTLOAD.
inline bool isZEXTLoad(const SDNode *N) {
  return isa<LoadSDNode>(N) &&
    cast<LoadSDNode>(N)->getExtensionType() == ISD::ZEXTLOAD;
}

/// Returns true if the specified node is an unindexed load.
inline bool isUNINDEXEDLoad(const SDNode *N) {
  return isa<LoadSDNode>(N) &&
    cast<LoadSDNode>(N)->getAddressingMode() == ISD::UNINDEXED;
}

/// Returns true if the specified node is a non-truncating
/// and unindexed store.
inline bool isNormalStore(const SDNode *N) {
  const StoreSDNode *St = dyn_cast<StoreSDNode>(N);
  return St && !St->isTruncatingStore() &&
    St->getAddressingMode() == ISD::UNINDEXED;
}

/// Returns true if the specified node is an unindexed store.
inline bool isUNINDEXEDStore(const SDNode *N) {
  return isa<StoreSDNode>(N) &&
    cast<StoreSDNode>(N)->getAddressingMode() == ISD::UNINDEXED;
}

/// Attempt to match a unary predicate against a scalar/splat constant or
/// every element of a constant BUILD_VECTOR.
/// If AllowUndef is true, then UNDEF elements will pass nullptr to Match.
bool matchUnaryPredicate(SDValue Op,
                         std::function<bool(ConstantSDNode *)> Match,
                         bool AllowUndefs = false);

/// Attempt to match a binary predicate against a pair of scalar/splat
/// constants or every element of a pair of constant BUILD_VECTORs.
/// If AllowUndef is true, then UNDEF elements will pass nullptr to Match.
/// If AllowTypeMismatch is true then RetType + ArgTypes don't need to match.
bool matchBinaryPredicate(
    SDValue LHS, SDValue RHS,
    std::function<bool(ConstantSDNode *, ConstantSDNode *)> Match,
    bool AllowUndefs = false, bool AllowTypeMismatch = false);

/// Returns true if the specified value is the overflow result from one
/// of the overflow intrinsic nodes.
inline bool isOverflowIntrOpRes(SDValue Op) {
  unsigned Opc = Op.getOpcode();
  return (Op.getResNo() == 1 &&
          (Opc == ISD::SADDO || Opc == ISD::UADDO || Opc == ISD::SSUBO ||
           Opc == ISD::USUBO || Opc == ISD::SMULO || Opc == ISD::UMULO));
}

2753} // end namespace ISD

2755} // end namespace llvm

2757#endif // LLVM_CODEGEN_SELECTIONDAGNODES_H