/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstCombineInternal.h

Bug Summary

File:	llvm/lib/Transforms/InstCombine/InstCombineInternal.h
Warning:	line 412, column 5 Forming reference to null pointer

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name InstructionCombining.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 -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/build-llvm/lib/Transforms/InstCombine -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/build-llvm/lib/Transforms/InstCombine -I /build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine -I /build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/build-llvm/lib/Transforms/InstCombine -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-08-28-193554-24367-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

→

1//===- InstructionCombining.cpp - Combine multiple instructions -----------===//
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// InstructionCombining - Combine instructions to form fewer, simple
10// instructions.  This pass does not modify the CFG.  This pass is where
11// algebraic simplification happens.
12//
13// This pass combines things like:
14//    %Y = add i32 %X, 1
15//    %Z = add i32 %Y, 1
16// into:
17//    %Z = add i32 %X, 2
18//
19// This is a simple worklist driven algorithm.
20//
21// This pass guarantees that the following canonicalizations are performed on
22// the program:
23//    1. If a binary operator has a constant operand, it is moved to the RHS
24//    2. Bitwise operators with constant operands are always grouped so that
25//       shifts are performed first, then or's, then and's, then xor's.
26//    3. Compare instructions are converted from <,>,<=,>= to ==,!= if possible
27//    4. All cmp instructions on boolean values are replaced with logical ops
28//    5. add X, X is represented as (X*2) => (X << 1)
29//    6. Multiplies with a power-of-two constant argument are transformed into
30//       shifts.
31//   ... etc.
32//
33//===----------------------------------------------------------------------===//

35#include "InstCombineInternal.h"
36#include "llvm-c/Initialization.h"
37#include "llvm-c/Transforms/InstCombine.h"
38#include "llvm/ADT/APInt.h"
39#include "llvm/ADT/ArrayRef.h"
40#include "llvm/ADT/DenseMap.h"
41#include "llvm/ADT/None.h"
42#include "llvm/ADT/SmallPtrSet.h"
43#include "llvm/ADT/SmallVector.h"
44#include "llvm/ADT/Statistic.h"
45#include "llvm/ADT/TinyPtrVector.h"
46#include "llvm/Analysis/AliasAnalysis.h"
47#include "llvm/Analysis/AssumptionCache.h"
48#include "llvm/Analysis/BasicAliasAnalysis.h"
49#include "llvm/Analysis/BlockFrequencyInfo.h"
50#include "llvm/Analysis/CFG.h"
51#include "llvm/Analysis/ConstantFolding.h"
52#include "llvm/Analysis/EHPersonalities.h"
53#include "llvm/Analysis/GlobalsModRef.h"
54#include "llvm/Analysis/InstructionSimplify.h"
55#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
56#include "llvm/Analysis/LoopInfo.h"
57#include "llvm/Analysis/MemoryBuiltins.h"
58#include "llvm/Analysis/OptimizationRemarkEmitter.h"
59#include "llvm/Analysis/ProfileSummaryInfo.h"
60#include "llvm/Analysis/TargetFolder.h"
61#include "llvm/Analysis/TargetLibraryInfo.h"
62#include "llvm/Analysis/TargetTransformInfo.h"
63#include "llvm/Analysis/ValueTracking.h"
64#include "llvm/Analysis/VectorUtils.h"
65#include "llvm/IR/BasicBlock.h"
66#include "llvm/IR/CFG.h"
67#include "llvm/IR/Constant.h"
68#include "llvm/IR/Constants.h"
69#include "llvm/IR/DIBuilder.h"
70#include "llvm/IR/DataLayout.h"
71#include "llvm/IR/DerivedTypes.h"
72#include "llvm/IR/Dominators.h"
73#include "llvm/IR/Function.h"
74#include "llvm/IR/GetElementPtrTypeIterator.h"
75#include "llvm/IR/IRBuilder.h"
76#include "llvm/IR/InstrTypes.h"
77#include "llvm/IR/Instruction.h"
78#include "llvm/IR/Instructions.h"
79#include "llvm/IR/IntrinsicInst.h"
80#include "llvm/IR/Intrinsics.h"
81#include "llvm/IR/LegacyPassManager.h"
82#include "llvm/IR/Metadata.h"
83#include "llvm/IR/Operator.h"
84#include "llvm/IR/PassManager.h"
85#include "llvm/IR/PatternMatch.h"
86#include "llvm/IR/Type.h"
87#include "llvm/IR/Use.h"
88#include "llvm/IR/User.h"
89#include "llvm/IR/Value.h"
90#include "llvm/IR/ValueHandle.h"
91#include "llvm/InitializePasses.h"
92#include "llvm/Pass.h"
93#include "llvm/Support/CBindingWrapping.h"
94#include "llvm/Support/Casting.h"
95#include "llvm/Support/CommandLine.h"
96#include "llvm/Support/Compiler.h"
97#include "llvm/Support/Debug.h"
98#include "llvm/Support/DebugCounter.h"
99#include "llvm/Support/ErrorHandling.h"
100#include "llvm/Support/KnownBits.h"
101#include "llvm/Support/raw_ostream.h"
102#include "llvm/Transforms/InstCombine/InstCombine.h"
103#include "llvm/Transforms/InstCombine/InstCombineWorklist.h"
104#include "llvm/Transforms/Utils/Local.h"
105#include <algorithm>
106#include <cassert>
107#include <cstdint>
108#include <memory>
109#include <string>
110#include <utility>

112using namespace llvm;
113using namespace llvm::PatternMatch;

115#define DEBUG_TYPE"instcombine" "instcombine"

117STATISTIC(NumWorklistIterations,static llvm::Statistic NumWorklistIterations = {"instcombine"
, "NumWorklistIterations", "Number of instruction combining iterations performed"
}
        "Number of instruction combining iterations performed")static llvm::Statistic NumWorklistIterations = {"instcombine"
, "NumWorklistIterations", "Number of instruction combining iterations performed"
};

120STATISTIC(NumCombined , "Number of insts combined")static llvm::Statistic NumCombined = {"instcombine", "NumCombined"
, "Number of insts combined"};
121STATISTIC(NumConstProp, "Number of constant folds")static llvm::Statistic NumConstProp = {"instcombine", "NumConstProp"
, "Number of constant folds"};
122STATISTIC(NumDeadInst , "Number of dead inst eliminated")static llvm::Statistic NumDeadInst = {"instcombine", "NumDeadInst"
, "Number of dead inst eliminated"};
123STATISTIC(NumSunkInst , "Number of instructions sunk")static llvm::Statistic NumSunkInst = {"instcombine", "NumSunkInst"
, "Number of instructions sunk"};
124STATISTIC(NumExpand,    "Number of expansions")static llvm::Statistic NumExpand = {"instcombine", "NumExpand"
, "Number of expansions"};
125STATISTIC(NumFactor   , "Number of factorizations")static llvm::Statistic NumFactor = {"instcombine", "NumFactor"
, "Number of factorizations"};
126STATISTIC(NumReassoc  , "Number of reassociations")static llvm::Statistic NumReassoc = {"instcombine", "NumReassoc"
, "Number of reassociations"};
127DEBUG_COUNTER(VisitCounter, "instcombine-visit",static const unsigned VisitCounter = DebugCounter::registerCounter
("instcombine-visit", "Controls which instructions are visited"
)
            "Controls which instructions are visited")static const unsigned VisitCounter = DebugCounter::registerCounter
("instcombine-visit", "Controls which instructions are visited"
);

130// FIXME: these limits eventually should be as low as 2.
131static constexpr unsigned InstCombineDefaultMaxIterations = 1000;
132#ifndef NDEBUG
133static constexpr unsigned InstCombineDefaultInfiniteLoopThreshold = 100;
134#else
135static constexpr unsigned InstCombineDefaultInfiniteLoopThreshold = 1000;
136#endif

138static cl::opt<bool>
139EnableCodeSinking("instcombine-code-sinking", cl::desc("Enable code sinking"),
                                            cl::init(true));

142static cl::opt<unsigned> LimitMaxIterations(
  "instcombine-max-iterations",
  cl::desc("Limit the maximum number of instruction combining iterations"),
  cl::init(InstCombineDefaultMaxIterations));

147static cl::opt<unsigned> InfiniteLoopDetectionThreshold(
  "instcombine-infinite-loop-threshold",
  cl::desc("Number of instruction combining iterations considered an "
           "infinite loop"),
  cl::init(InstCombineDefaultInfiniteLoopThreshold), cl::Hidden);

153static cl::opt<unsigned>
154MaxArraySize("instcombine-maxarray-size", cl::init(1024),
           cl::desc("Maximum array size considered when doing a combine"));

157// FIXME: Remove this flag when it is no longer necessary to convert
158// llvm.dbg.declare to avoid inaccurate debug info. Setting this to false
159// increases variable availability at the cost of accuracy. Variables that
160// cannot be promoted by mem2reg or SROA will be described as living in memory
161// for their entire lifetime. However, passes like DSE and instcombine can
162// delete stores to the alloca, leading to misleading and inaccurate debug
163// information. This flag can be removed when those passes are fixed.
164static cl::opt<unsigned> ShouldLowerDbgDeclare("instcombine-lower-dbg-declare",
                                             cl::Hidden, cl::init(true));

167Optional<Instruction *>
168InstCombiner::targetInstCombineIntrinsic(IntrinsicInst &II) {
// Handle target specific intrinsics
if (II.getCalledFunction()->isTargetIntrinsic()) {
  return TTI.instCombineIntrinsic(*this, II);
}
return None;
174}

176Optional<Value *> InstCombiner::targetSimplifyDemandedUseBitsIntrinsic(
  IntrinsicInst &II, APInt DemandedMask, KnownBits &Known,
  bool &KnownBitsComputed) {
// Handle target specific intrinsics
if (II.getCalledFunction()->isTargetIntrinsic()) {
  return TTI.simplifyDemandedUseBitsIntrinsic(*this, II, DemandedMask, Known,
                                              KnownBitsComputed);
}
return None;
185}

187Optional<Value *> InstCombiner::targetSimplifyDemandedVectorEltsIntrinsic(
  IntrinsicInst &II, APInt DemandedElts, APInt &UndefElts, APInt &UndefElts2,
  APInt &UndefElts3,
  std::function<void(Instruction *, unsigned, APInt, APInt &)>
      SimplifyAndSetOp) {
// Handle target specific intrinsics
if (II.getCalledFunction()->isTargetIntrinsic()) {
  return TTI.simplifyDemandedVectorEltsIntrinsic(
      *this, II, DemandedElts, UndefElts, UndefElts2, UndefElts3,
      SimplifyAndSetOp);
}
return None;
199}

201Value *InstCombinerImpl::EmitGEPOffset(User *GEP) {
return llvm::EmitGEPOffset(&Builder, DL, GEP);
203}

205/// Return true if it is desirable to convert an integer computation from a
206/// given bit width to a new bit width.
207/// We don't want to convert from a legal to an illegal type or from a smaller
208/// to a larger illegal type. A width of '1' is always treated as a legal type
209/// because i1 is a fundamental type in IR, and there are many specialized
210/// optimizations for i1 types. Widths of 8, 16 or 32 are equally treated as
211/// legal to convert to, in order to open up more combining opportunities.
212/// NOTE: this treats i8, i16 and i32 specially, due to them being so common
213/// from frontend languages.
214bool InstCombinerImpl::shouldChangeType(unsigned FromWidth,
                                      unsigned ToWidth) const {
bool FromLegal = FromWidth == 1 || DL.isLegalInteger(FromWidth);
bool ToLegal = ToWidth == 1 || DL.isLegalInteger(ToWidth);

// Convert to widths of 8, 16 or 32 even if they are not legal types. Only
// shrink types, to prevent infinite loops.
if (ToWidth < FromWidth && (ToWidth == 8 || ToWidth == 16 || ToWidth == 32))
  return true;

// If this is a legal integer from type, and the result would be an illegal
// type, don't do the transformation.
if (FromLegal && !ToLegal)
  return false;

// Otherwise, if both are illegal, do not increase the size of the result. We
// do allow things like i160 -> i64, but not i64 -> i160.
if (!FromLegal && !ToLegal && ToWidth > FromWidth)
  return false;

return true;
235}

237/// Return true if it is desirable to convert a computation from 'From' to 'To'.
238/// We don't want to convert from a legal to an illegal type or from a smaller
239/// to a larger illegal type. i1 is always treated as a legal type because it is
240/// a fundamental type in IR, and there are many specialized optimizations for
241/// i1 types.
242bool InstCombinerImpl::shouldChangeType(Type *From, Type *To) const {
// TODO: This could be extended to allow vectors. Datalayout changes might be
// needed to properly support that.
if (!From->isIntegerTy() || !To->isIntegerTy())
  return false;

unsigned FromWidth = From->getPrimitiveSizeInBits();
unsigned ToWidth = To->getPrimitiveSizeInBits();
return shouldChangeType(FromWidth, ToWidth);
251}

253// Return true, if No Signed Wrap should be maintained for I.
254// The No Signed Wrap flag can be kept if the operation "B (I.getOpcode) C",
255// where both B and C should be ConstantInts, results in a constant that does
256// not overflow. This function only handles the Add and Sub opcodes. For
257// all other opcodes, the function conservatively returns false.
258static bool maintainNoSignedWrap(BinaryOperator &I, Value *B, Value *C) {
auto *OBO = dyn_cast<OverflowingBinaryOperator>(&I);
if (!OBO || !OBO->hasNoSignedWrap())
  return false;

// We reason about Add and Sub Only.
Instruction::BinaryOps Opcode = I.getOpcode();
if (Opcode != Instruction::Add && Opcode != Instruction::Sub)
  return false;

const APInt *BVal, *CVal;
if (!match(B, m_APInt(BVal)) || !match(C, m_APInt(CVal)))
  return false;

bool Overflow = false;
if (Opcode == Instruction::Add)
  (void)BVal->sadd_ov(*CVal, Overflow);
else
  (void)BVal->ssub_ov(*CVal, Overflow);

return !Overflow;
279}

281static bool hasNoUnsignedWrap(BinaryOperator &I) {
auto *OBO = dyn_cast<OverflowingBinaryOperator>(&I);
return OBO && OBO->hasNoUnsignedWrap();
284}

286static bool hasNoSignedWrap(BinaryOperator &I) {
auto *OBO = dyn_cast<OverflowingBinaryOperator>(&I);
return OBO && OBO->hasNoSignedWrap();
289}

291/// Conservatively clears subclassOptionalData after a reassociation or
292/// commutation. We preserve fast-math flags when applicable as they can be
293/// preserved.
294static void ClearSubclassDataAfterReassociation(BinaryOperator &I) {
FPMathOperator *FPMO = dyn_cast<FPMathOperator>(&I);
if (!FPMO) {
  I.clearSubclassOptionalData();
  return;
}

FastMathFlags FMF = I.getFastMathFlags();
I.clearSubclassOptionalData();
I.setFastMathFlags(FMF);
304}

306/// Combine constant operands of associative operations either before or after a
307/// cast to eliminate one of the associative operations:
308/// (op (cast (op X, C2)), C1) --> (cast (op X, op (C1, C2)))
309/// (op (cast (op X, C2)), C1) --> (op (cast X), op (C1, C2))
310static bool simplifyAssocCastAssoc(BinaryOperator *BinOp1,
                                 InstCombinerImpl &IC) {
auto *Cast = dyn_cast<CastInst>(BinOp1->getOperand(0));
if (!Cast || !Cast->hasOneUse())
  return false;

// TODO: Enhance logic for other casts and remove this check.
auto CastOpcode = Cast->getOpcode();
if (CastOpcode != Instruction::ZExt)
  return false;

// TODO: Enhance logic for other BinOps and remove this check.
if (!BinOp1->isBitwiseLogicOp())
  return false;

auto AssocOpcode = BinOp1->getOpcode();
auto *BinOp2 = dyn_cast<BinaryOperator>(Cast->getOperand(0));
if (!BinOp2 || !BinOp2->hasOneUse() || BinOp2->getOpcode() != AssocOpcode)
  return false;

Constant *C1, *C2;
if (!match(BinOp1->getOperand(1), m_Constant(C1)) ||
    !match(BinOp2->getOperand(1), m_Constant(C2)))
  return false;

// TODO: This assumes a zext cast.
// Eg, if it was a trunc, we'd cast C1 to the source type because casting C2
// to the destination type might lose bits.

// Fold the constants together in the destination type:
// (op (cast (op X, C2)), C1) --> (op (cast X), FoldedC)
Type *DestTy = C1->getType();
Constant *CastC2 = ConstantExpr::getCast(CastOpcode, C2, DestTy);
Constant *FoldedC = ConstantExpr::get(AssocOpcode, C1, CastC2);
IC.replaceOperand(*Cast, 0, BinOp2->getOperand(0));
IC.replaceOperand(*BinOp1, 1, FoldedC);
return true;
347}

349// Simplifies IntToPtr/PtrToInt RoundTrip Cast To BitCast.
350// inttoptr ( ptrtoint (x) ) --> x
351Value *InstCombinerImpl::simplifyIntToPtrRoundTripCast(Value *Val) {
auto *IntToPtr = dyn_cast<IntToPtrInst>(Val);
if (IntToPtr && DL.getPointerTypeSizeInBits(IntToPtr->getDestTy()) ==
                    DL.getTypeSizeInBits(IntToPtr->getSrcTy())) {
  auto *PtrToInt = dyn_cast<PtrToIntInst>(IntToPtr->getOperand(0));
  Type *CastTy = IntToPtr->getDestTy();
  if (PtrToInt &&
      CastTy->getPointerAddressSpace() ==
          PtrToInt->getSrcTy()->getPointerAddressSpace() &&
      DL.getPointerTypeSizeInBits(PtrToInt->getSrcTy()) ==
          DL.getTypeSizeInBits(PtrToInt->getDestTy())) {
    return CastInst::CreateBitOrPointerCast(PtrToInt->getOperand(0), CastTy,
                                            "", PtrToInt);
  }
}
return nullptr;
367}

369/// This performs a few simplifications for operators that are associative or
370/// commutative:
371///
372///  Commutative operators:
373///
374///  1. Order operands such that they are listed from right (least complex) to
375///     left (most complex).  This puts constants before unary operators before
376///     binary operators.
377///
378///  Associative operators:
379///
380///  2. Transform: "(A op B) op C" ==> "A op (B op C)" if "B op C" simplifies.
381///  3. Transform: "A op (B op C)" ==> "(A op B) op C" if "A op B" simplifies.
382///
383///  Associative and commutative operators:
384///
385///  4. Transform: "(A op B) op C" ==> "(C op A) op B" if "C op A" simplifies.
386///  5. Transform: "A op (B op C)" ==> "B op (C op A)" if "C op A" simplifies.
387///  6. Transform: "(A op C1) op (B op C2)" ==> "(A op B) op (C1 op C2)"
388///     if C1 and C2 are constants.
389bool InstCombinerImpl::SimplifyAssociativeOrCommutative(BinaryOperator &I) {
Instruction::BinaryOps Opcode = I.getOpcode();
bool Changed = false;

do {
  // Order operands such that they are listed from right (least complex) to
  // left (most complex).  This puts constants before unary operators before
  // binary operators.
  if (I.isCommutative() && getComplexity(I.getOperand(0)) <
      getComplexity(I.getOperand(1)))
    Changed = !I.swapOperands();

  BinaryOperator *Op0 = dyn_cast<BinaryOperator>(I.getOperand(0));
  BinaryOperator *Op1 = dyn_cast<BinaryOperator>(I.getOperand(1));

  if (I.isAssociative()) {
    // Transform: "(A op B) op C" ==> "A op (B op C)" if "B op C" simplifies.
    if (Op0 && Op0->getOpcode() == Opcode) {
      Value *A = Op0->getOperand(0);
      Value *B = Op0->getOperand(1);
      Value *C = I.getOperand(1);

      // Does "B op C" simplify?
      if (Value *V = SimplifyBinOp(Opcode, B, C, SQ.getWithInstruction(&I))) {
        // It simplifies to V.  Form "A op V".
        replaceOperand(I, 0, A);
        replaceOperand(I, 1, V);
        bool IsNUW = hasNoUnsignedWrap(I) && hasNoUnsignedWrap(*Op0);
        bool IsNSW = maintainNoSignedWrap(I, B, C) && hasNoSignedWrap(*Op0);

        // Conservatively clear all optional flags since they may not be
        // preserved by the reassociation. Reset nsw/nuw based on the above
        // analysis.
        ClearSubclassDataAfterReassociation(I);

        // Note: this is only valid because SimplifyBinOp doesn't look at
        // the operands to Op0.
        if (IsNUW)
          I.setHasNoUnsignedWrap(true);

        if (IsNSW)
          I.setHasNoSignedWrap(true);

        Changed = true;
        ++NumReassoc;
        continue;
      }
    }

    // Transform: "A op (B op C)" ==> "(A op B) op C" if "A op B" simplifies.
    if (Op1 && Op1->getOpcode() == Opcode) {
      Value *A = I.getOperand(0);
      Value *B = Op1->getOperand(0);
      Value *C = Op1->getOperand(1);

      // Does "A op B" simplify?
      if (Value *V = SimplifyBinOp(Opcode, A, B, SQ.getWithInstruction(&I))) {
        // It simplifies to V.  Form "V op C".
        replaceOperand(I, 0, V);
        replaceOperand(I, 1, C);
        // Conservatively clear the optional flags, since they may not be
        // preserved by the reassociation.
        ClearSubclassDataAfterReassociation(I);
        Changed = true;
        ++NumReassoc;
        continue;
      }
    }
  }

  if (I.isAssociative() && I.isCommutative()) {
    if (simplifyAssocCastAssoc(&I, *this)) {
      Changed = true;
      ++NumReassoc;
      continue;
    }

    // Transform: "(A op B) op C" ==> "(C op A) op B" if "C op A" simplifies.
    if (Op0 && Op0->getOpcode() == Opcode) {
      Value *A = Op0->getOperand(0);
      Value *B = Op0->getOperand(1);
      Value *C = I.getOperand(1);

      // Does "C op A" simplify?
      if (Value *V = SimplifyBinOp(Opcode, C, A, SQ.getWithInstruction(&I))) {
        // It simplifies to V.  Form "V op B".
        replaceOperand(I, 0, V);
        replaceOperand(I, 1, B);
        // Conservatively clear the optional flags, since they may not be
        // preserved by the reassociation.
        ClearSubclassDataAfterReassociation(I);
        Changed = true;
        ++NumReassoc;
        continue;
      }
    }

    // Transform: "A op (B op C)" ==> "B op (C op A)" if "C op A" simplifies.
    if (Op1 && Op1->getOpcode() == Opcode) {
      Value *A = I.getOperand(0);
      Value *B = Op1->getOperand(0);
      Value *C = Op1->getOperand(1);

      // Does "C op A" simplify?
      if (Value *V = SimplifyBinOp(Opcode, C, A, SQ.getWithInstruction(&I))) {
        // It simplifies to V.  Form "B op V".
        replaceOperand(I, 0, B);
        replaceOperand(I, 1, V);
        // Conservatively clear the optional flags, since they may not be
        // preserved by the reassociation.
        ClearSubclassDataAfterReassociation(I);
        Changed = true;
        ++NumReassoc;
        continue;
      }
    }

    // Transform: "(A op C1) op (B op C2)" ==> "(A op B) op (C1 op C2)"
    // if C1 and C2 are constants.
    Value *A, *B;
    Constant *C1, *C2;
    if (Op0 && Op1 &&
        Op0->getOpcode() == Opcode && Op1->getOpcode() == Opcode &&
        match(Op0, m_OneUse(m_BinOp(m_Value(A), m_Constant(C1)))) &&
        match(Op1, m_OneUse(m_BinOp(m_Value(B), m_Constant(C2))))) {
      bool IsNUW = hasNoUnsignedWrap(I) &&
         hasNoUnsignedWrap(*Op0) &&
         hasNoUnsignedWrap(*Op1);
       BinaryOperator *NewBO = (IsNUW && Opcode == Instruction::Add) ?
         BinaryOperator::CreateNUW(Opcode, A, B) :
         BinaryOperator::Create(Opcode, A, B);

       if (isa<FPMathOperator>(NewBO)) {
        FastMathFlags Flags = I.getFastMathFlags();
        Flags &= Op0->getFastMathFlags();
        Flags &= Op1->getFastMathFlags();
        NewBO->setFastMathFlags(Flags);
      }
      InsertNewInstWith(NewBO, I);
      NewBO->takeName(Op1);
      replaceOperand(I, 0, NewBO);
      replaceOperand(I, 1, ConstantExpr::get(Opcode, C1, C2));
      // Conservatively clear the optional flags, since they may not be
      // preserved by the reassociation.
      ClearSubclassDataAfterReassociation(I);
      if (IsNUW)
        I.setHasNoUnsignedWrap(true);

      Changed = true;
      continue;
    }
  }

  // No further simplifications.
  return Changed;
} while (true);
545}

547/// Return whether "X LOp (Y ROp Z)" is always equal to
548/// "(X LOp Y) ROp (X LOp Z)".
549static bool leftDistributesOverRight(Instruction::BinaryOps LOp,
                                   Instruction::BinaryOps ROp) {
// X & (Y | Z) <--> (X & Y) | (X & Z)
// X & (Y ^ Z) <--> (X & Y) ^ (X & Z)
if (LOp == Instruction::And)
  return ROp == Instruction::Or || ROp == Instruction::Xor;

// X | (Y & Z) <--> (X | Y) & (X | Z)
if (LOp == Instruction::Or)
  return ROp == Instruction::And;

// X * (Y + Z) <--> (X * Y) + (X * Z)
// X * (Y - Z) <--> (X * Y) - (X * Z)
if (LOp == Instruction::Mul)
  return ROp == Instruction::Add || ROp == Instruction::Sub;

return false;
566}

568/// Return whether "(X LOp Y) ROp Z" is always equal to
569/// "(X ROp Z) LOp (Y ROp Z)".
570static bool rightDistributesOverLeft(Instruction::BinaryOps LOp,
                                   Instruction::BinaryOps ROp) {
if (Instruction::isCommutative(ROp))
  return leftDistributesOverRight(ROp, LOp);

// (X {&|^} Y) >> Z <--> (X >> Z) {&|^} (Y >> Z) for all shifts.
return Instruction::isBitwiseLogicOp(LOp) && Instruction::isShift(ROp);

// TODO: It would be nice to handle division, aka "(X + Y)/Z = X/Z + Y/Z",
// but this requires knowing that the addition does not overflow and other
// such subtleties.
581}

583/// This function returns identity value for given opcode, which can be used to
584/// factor patterns like (X * 2) + X ==> (X * 2) + (X * 1) ==> X * (2 + 1).
585static Value *getIdentityValue(Instruction::BinaryOps Opcode, Value *V) {
if (isa<Constant>(V))
  return nullptr;

return ConstantExpr::getBinOpIdentity(Opcode, V->getType());
590}

592/// This function predicates factorization using distributive laws. By default,
593/// it just returns the 'Op' inputs. But for special-cases like
594/// 'add(shl(X, 5), ...)', this function will have TopOpcode == Instruction::Add
595/// and Op = shl(X, 5). The 'shl' is treated as the more general 'mul X, 32' to
596/// allow more factorization opportunities.
597static Instruction::BinaryOps
598getBinOpsForFactorization(Instruction::BinaryOps TopOpcode, BinaryOperator *Op,
                        Value *&LHS, Value *&RHS) {
assert(Op && "Expected a binary operator")(static_cast <bool> (Op && "Expected a binary operator"
) ? void (0) : __assert_fail ("Op && \"Expected a binary operator\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 600, __extension__ __PRETTY_FUNCTION__));
LHS = Op->getOperand(0);
RHS = Op->getOperand(1);
if (TopOpcode == Instruction::Add || TopOpcode == Instruction::Sub) {
  Constant *C;
  if (match(Op, m_Shl(m_Value(), m_Constant(C)))) {
    // X << C --> X * (1 << C)
    RHS = ConstantExpr::getShl(ConstantInt::get(Op->getType(), 1), C);
    return Instruction::Mul;
  }
  // TODO: We can add other conversions e.g. shr => div etc.
}
return Op->getOpcode();
613}

615/// This tries to simplify binary operations by factorizing out common terms
616/// (e. g. "(A*B)+(A*C)" -> "A*(B+C)").
617Value *InstCombinerImpl::tryFactorization(BinaryOperator &I,
                                        Instruction::BinaryOps InnerOpcode,
                                        Value *A, Value *B, Value *C,
                                        Value *D) {
assert(A && B && C && D && "All values must be provided")(static_cast <bool> (A && B && C &&
 D && "All values must be provided") ? void (0) : __assert_fail
 ("A && B && C && D && \"All values must be provided\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 621, __extension__ __PRETTY_FUNCTION__));

Value *V = nullptr;
Value *SimplifiedInst = nullptr;
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
Instruction::BinaryOps TopLevelOpcode = I.getOpcode();

// Does "X op' Y" always equal "Y op' X"?
bool InnerCommutative = Instruction::isCommutative(InnerOpcode);

// Does "X op' (Y op Z)" always equal "(X op' Y) op (X op' Z)"?
if (leftDistributesOverRight(InnerOpcode, TopLevelOpcode))
  // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
  // commutative case, "(A op' B) op (C op' A)"?
  if (A == C || (InnerCommutative && A == D)) {
    if (A != C)
      std::swap(C, D);
    // Consider forming "A op' (B op D)".
    // If "B op D" simplifies then it can be formed with no cost.
    V = SimplifyBinOp(TopLevelOpcode, B, D, SQ.getWithInstruction(&I));
    // If "B op D" doesn't simplify then only go on if both of the existing
    // operations "A op' B" and "C op' D" will be zapped as no longer used.
    if (!V && LHS->hasOneUse() && RHS->hasOneUse())
      V = Builder.CreateBinOp(TopLevelOpcode, B, D, RHS->getName());
    if (V) {
      SimplifiedInst = Builder.CreateBinOp(InnerOpcode, A, V);
    }
  }

// Does "(X op Y) op' Z" always equal "(X op' Z) op (Y op' Z)"?
if (!SimplifiedInst && rightDistributesOverLeft(TopLevelOpcode, InnerOpcode))
  // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
  // commutative case, "(A op' B) op (B op' D)"?
  if (B == D || (InnerCommutative && B == C)) {
    if (B != D)
      std::swap(C, D);
    // Consider forming "(A op C) op' B".
    // If "A op C" simplifies then it can be formed with no cost.
    V = SimplifyBinOp(TopLevelOpcode, A, C, SQ.getWithInstruction(&I));

    // If "A op C" doesn't simplify then only go on if both of the existing
    // operations "A op' B" and "C op' D" will be zapped as no longer used.
    if (!V && LHS->hasOneUse() && RHS->hasOneUse())
      V = Builder.CreateBinOp(TopLevelOpcode, A, C, LHS->getName());
    if (V) {
      SimplifiedInst = Builder.CreateBinOp(InnerOpcode, V, B);
    }
  }

if (SimplifiedInst) {
  ++NumFactor;
  SimplifiedInst->takeName(&I);

  // Check if we can add NSW/NUW flags to SimplifiedInst. If so, set them.
  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(SimplifiedInst)) {
    if (isa<OverflowingBinaryOperator>(SimplifiedInst)) {
      bool HasNSW = false;
      bool HasNUW = false;
      if (isa<OverflowingBinaryOperator>(&I)) {
        HasNSW = I.hasNoSignedWrap();
        HasNUW = I.hasNoUnsignedWrap();
      }

      if (auto *LOBO = dyn_cast<OverflowingBinaryOperator>(LHS)) {
        HasNSW &= LOBO->hasNoSignedWrap();
        HasNUW &= LOBO->hasNoUnsignedWrap();
      }

      if (auto *ROBO = dyn_cast<OverflowingBinaryOperator>(RHS)) {
        HasNSW &= ROBO->hasNoSignedWrap();
        HasNUW &= ROBO->hasNoUnsignedWrap();
      }

      if (TopLevelOpcode == Instruction::Add &&
          InnerOpcode == Instruction::Mul) {
        // We can propagate 'nsw' if we know that
        //  %Y = mul nsw i16 %X, C
        //  %Z = add nsw i16 %Y, %X
        // =>
        //  %Z = mul nsw i16 %X, C+1
        //
        // iff C+1 isn't INT_MIN
        const APInt *CInt;
        if (match(V, m_APInt(CInt))) {
          if (!CInt->isMinSignedValue())
            BO->setHasNoSignedWrap(HasNSW);
        }

        // nuw can be propagated with any constant or nuw value.
        BO->setHasNoUnsignedWrap(HasNUW);
      }
    }
  }
}
return SimplifiedInst;
716}

718/// This tries to simplify binary operations which some other binary operation
719/// distributes over either by factorizing out common terms
720/// (eg "(A*B)+(A*C)" -> "A*(B+C)") or expanding out if this results in
721/// simplifications (eg: "A & (B | C) -> (A&B) | (A&C)" if this is a win).
722/// Returns the simplified value, or null if it didn't simplify.
723Value *InstCombinerImpl::SimplifyUsingDistributiveLaws(BinaryOperator &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
Instruction::BinaryOps TopLevelOpcode = I.getOpcode();

{
  // Factorization.
  Value *A, *B, *C, *D;
  Instruction::BinaryOps LHSOpcode, RHSOpcode;
  if (Op0)
    LHSOpcode = getBinOpsForFactorization(TopLevelOpcode, Op0, A, B);
  if (Op1)
    RHSOpcode = getBinOpsForFactorization(TopLevelOpcode, Op1, C, D);

  // The instruction has the form "(A op' B) op (C op' D)".  Try to factorize
  // a common term.
  if (Op0 && Op1 && LHSOpcode == RHSOpcode)
    if (Value *V = tryFactorization(I, LHSOpcode, A, B, C, D))
      return V;

  // The instruction has the form "(A op' B) op (C)".  Try to factorize common
  // term.
  if (Op0)
    if (Value *Ident = getIdentityValue(LHSOpcode, RHS))
      if (Value *V = tryFactorization(I, LHSOpcode, A, B, RHS, Ident))
        return V;

  // The instruction has the form "(B) op (C op' D)".  Try to factorize common
  // term.
  if (Op1)
    if (Value *Ident = getIdentityValue(RHSOpcode, LHS))
      if (Value *V = tryFactorization(I, RHSOpcode, LHS, Ident, C, D))
        return V;
}

// Expansion.
if (Op0 && rightDistributesOverLeft(Op0->getOpcode(), TopLevelOpcode)) {
  // The instruction has the form "(A op' B) op C".  See if expanding it out
  // to "(A op C) op' (B op C)" results in simplifications.
  Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
  Instruction::BinaryOps InnerOpcode = Op0->getOpcode(); // op'

  // Disable the use of undef because it's not safe to distribute undef.
  auto SQDistributive = SQ.getWithInstruction(&I).getWithoutUndef();
  Value *L = SimplifyBinOp(TopLevelOpcode, A, C, SQDistributive);
  Value *R = SimplifyBinOp(TopLevelOpcode, B, C, SQDistributive);

  // Do "A op C" and "B op C" both simplify?
  if (L && R) {
    // They do! Return "L op' R".
    ++NumExpand;
    C = Builder.CreateBinOp(InnerOpcode, L, R);
    C->takeName(&I);
    return C;
  }

  // Does "A op C" simplify to the identity value for the inner opcode?
  if (L && L == ConstantExpr::getBinOpIdentity(InnerOpcode, L->getType())) {
    // They do! Return "B op C".
    ++NumExpand;
    C = Builder.CreateBinOp(TopLevelOpcode, B, C);
    C->takeName(&I);
    return C;
  }

  // Does "B op C" simplify to the identity value for the inner opcode?
  if (R && R == ConstantExpr::getBinOpIdentity(InnerOpcode, R->getType())) {
    // They do! Return "A op C".
    ++NumExpand;
    C = Builder.CreateBinOp(TopLevelOpcode, A, C);
    C->takeName(&I);
    return C;
  }
}

if (Op1 && leftDistributesOverRight(TopLevelOpcode, Op1->getOpcode())) {
  // The instruction has the form "A op (B op' C)".  See if expanding it out
  // to "(A op B) op' (A op C)" results in simplifications.
  Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
  Instruction::BinaryOps InnerOpcode = Op1->getOpcode(); // op'

  // Disable the use of undef because it's not safe to distribute undef.
  auto SQDistributive = SQ.getWithInstruction(&I).getWithoutUndef();
  Value *L = SimplifyBinOp(TopLevelOpcode, A, B, SQDistributive);
  Value *R = SimplifyBinOp(TopLevelOpcode, A, C, SQDistributive);

  // Do "A op B" and "A op C" both simplify?
  if (L && R) {
    // They do! Return "L op' R".
    ++NumExpand;
    A = Builder.CreateBinOp(InnerOpcode, L, R);
    A->takeName(&I);
    return A;
  }

  // Does "A op B" simplify to the identity value for the inner opcode?
  if (L && L == ConstantExpr::getBinOpIdentity(InnerOpcode, L->getType())) {
    // They do! Return "A op C".
    ++NumExpand;
    A = Builder.CreateBinOp(TopLevelOpcode, A, C);
    A->takeName(&I);
    return A;
  }

  // Does "A op C" simplify to the identity value for the inner opcode?
  if (R && R == ConstantExpr::getBinOpIdentity(InnerOpcode, R->getType())) {
    // They do! Return "A op B".
    ++NumExpand;
    A = Builder.CreateBinOp(TopLevelOpcode, A, B);
    A->takeName(&I);
    return A;
  }
}

return SimplifySelectsFeedingBinaryOp(I, LHS, RHS);
839}

841Value *InstCombinerImpl::SimplifySelectsFeedingBinaryOp(BinaryOperator &I,
                                                      Value *LHS,
                                                      Value *RHS) {
Value *A, *B, *C, *D, *E, *F;
bool LHSIsSelect = match(LHS, m_Select(m_Value(A), m_Value(B), m_Value(C)));
bool RHSIsSelect = match(RHS, m_Select(m_Value(D), m_Value(E), m_Value(F)));
if (!LHSIsSelect && !RHSIsSelect)
  return nullptr;

FastMathFlags FMF;
BuilderTy::FastMathFlagGuard Guard(Builder);
if (isa<FPMathOperator>(&I)) {
  FMF = I.getFastMathFlags();
  Builder.setFastMathFlags(FMF);
}

Instruction::BinaryOps Opcode = I.getOpcode();
SimplifyQuery Q = SQ.getWithInstruction(&I);

Value *Cond, *True = nullptr, *False = nullptr;
if (LHSIsSelect && RHSIsSelect && A == D) {
  // (A ? B : C) op (A ? E : F) -> A ? (B op E) : (C op F)
  Cond = A;
  True = SimplifyBinOp(Opcode, B, E, FMF, Q);
  False = SimplifyBinOp(Opcode, C, F, FMF, Q);

  if (LHS->hasOneUse() && RHS->hasOneUse()) {
    if (False && !True)
      True = Builder.CreateBinOp(Opcode, B, E);
    else if (True && !False)
      False = Builder.CreateBinOp(Opcode, C, F);
  }
} else if (LHSIsSelect && LHS->hasOneUse()) {
  // (A ? B : C) op Y -> A ? (B op Y) : (C op Y)
  Cond = A;
  True = SimplifyBinOp(Opcode, B, RHS, FMF, Q);
  False = SimplifyBinOp(Opcode, C, RHS, FMF, Q);
} else if (RHSIsSelect && RHS->hasOneUse()) {
  // X op (D ? E : F) -> D ? (X op E) : (X op F)
  Cond = D;
  True = SimplifyBinOp(Opcode, LHS, E, FMF, Q);
  False = SimplifyBinOp(Opcode, LHS, F, FMF, Q);
}

if (!True || !False)
  return nullptr;

Value *SI = Builder.CreateSelect(Cond, True, False);
SI->takeName(&I);
return SI;
891}

893/// Freely adapt every user of V as-if V was changed to !V.
894/// WARNING: only if canFreelyInvertAllUsersOf() said this can be done.
895void InstCombinerImpl::freelyInvertAllUsersOf(Value *I) {
for (User *U : I->users()) {
  switch (cast<Instruction>(U)->getOpcode()) {
  case Instruction::Select: {
    auto *SI = cast<SelectInst>(U);
    SI->swapValues();
    SI->swapProfMetadata();
    break;
  }
  case Instruction::Br:
    cast<BranchInst>(U)->swapSuccessors(); // swaps prof metadata too
    break;
  case Instruction::Xor:
    replaceInstUsesWith(cast<Instruction>(*U), I);
    break;
  default:
    llvm_unreachable("Got unexpected user - out of sync with "::llvm::llvm_unreachable_internal("Got unexpected user - out of sync with "
 "canFreelyInvertAllUsersOf() ?", "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 912)
                     "canFreelyInvertAllUsersOf() ?")::llvm::llvm_unreachable_internal("Got unexpected user - out of sync with "
 "canFreelyInvertAllUsersOf() ?", "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 912);
  }
}
915}

917/// Given a 'sub' instruction, return the RHS of the instruction if the LHS is a
918/// constant zero (which is the 'negate' form).
919Value *InstCombinerImpl::dyn_castNegVal(Value *V) const {
Value *NegV;
if (match(V, m_Neg(m_Value(NegV))))
  return NegV;

// Constants can be considered to be negated values if they can be folded.
if (ConstantInt *C = dyn_cast<ConstantInt>(V))
  return ConstantExpr::getNeg(C);

if (ConstantDataVector *C = dyn_cast<ConstantDataVector>(V))
  if (C->getType()->getElementType()->isIntegerTy())
    return ConstantExpr::getNeg(C);

if (ConstantVector *CV = dyn_cast<ConstantVector>(V)) {
  for (unsigned i = 0, e = CV->getNumOperands(); i != e; ++i) {
    Constant *Elt = CV->getAggregateElement(i);
    if (!Elt)
      return nullptr;

    if (isa<UndefValue>(Elt))
      continue;

    if (!isa<ConstantInt>(Elt))
      return nullptr;
  }
  return ConstantExpr::getNeg(CV);
}

// Negate integer vector splats.
if (auto *CV = dyn_cast<Constant>(V))
  if (CV->getType()->isVectorTy() &&
      CV->getType()->getScalarType()->isIntegerTy() && CV->getSplatValue())
    return ConstantExpr::getNeg(CV);

return nullptr;
954}

956static Value *foldOperationIntoSelectOperand(Instruction &I, Value *SO,
                                           InstCombiner::BuilderTy &Builder) {
if (auto *Cast = dyn_cast<CastInst>(&I))
  return Builder.CreateCast(Cast->getOpcode(), SO, I.getType());

if (auto *II = dyn_cast<IntrinsicInst>(&I)) {
  assert(canConstantFoldCallTo(II, cast<Function>(II->getCalledOperand())) &&(static_cast <bool> (canConstantFoldCallTo(II, cast<
Function>(II->getCalledOperand())) && "Expected constant-foldable intrinsic"
) ? void (0) : __assert_fail ("canConstantFoldCallTo(II, cast<Function>(II->getCalledOperand())) && \"Expected constant-foldable intrinsic\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 963, __extension__ __PRETTY_FUNCTION__))
         "Expected constant-foldable intrinsic")(static_cast <bool> (canConstantFoldCallTo(II, cast<
Function>(II->getCalledOperand())) && "Expected constant-foldable intrinsic"
) ? void (0) : __assert_fail ("canConstantFoldCallTo(II, cast<Function>(II->getCalledOperand())) && \"Expected constant-foldable intrinsic\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 963, __extension__ __PRETTY_FUNCTION__));
  Intrinsic::ID IID = II->getIntrinsicID();
  if (II->getNumArgOperands() == 1)
    return Builder.CreateUnaryIntrinsic(IID, SO);

  // This works for real binary ops like min/max (where we always expect the
  // constant operand to be canonicalized as op1) and unary ops with a bonus
  // constant argument like ctlz/cttz.
  // TODO: Handle non-commutative binary intrinsics as below for binops.
  assert(II->getNumArgOperands() == 2 && "Expected binary intrinsic")(static_cast <bool> (II->getNumArgOperands() == 2 &&
 "Expected binary intrinsic") ? void (0) : __assert_fail ("II->getNumArgOperands() == 2 && \"Expected binary intrinsic\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 972, __extension__ __PRETTY_FUNCTION__));
  assert(isa<Constant>(II->getArgOperand(1)) && "Expected constant operand")(static_cast <bool> (isa<Constant>(II->getArgOperand
(1)) && "Expected constant operand") ? void (0) : __assert_fail
 ("isa<Constant>(II->getArgOperand(1)) && \"Expected constant operand\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 973, __extension__ __PRETTY_FUNCTION__));
  return Builder.CreateBinaryIntrinsic(IID, SO, II->getArgOperand(1));
}

assert(I.isBinaryOp() && "Unexpected opcode for select folding")(static_cast <bool> (I.isBinaryOp() && "Unexpected opcode for select folding"
) ? void (0) : __assert_fail ("I.isBinaryOp() && \"Unexpected opcode for select folding\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 977, __extension__ __PRETTY_FUNCTION__));

// Figure out if the constant is the left or the right argument.
bool ConstIsRHS = isa<Constant>(I.getOperand(1));
Constant *ConstOperand = cast<Constant>(I.getOperand(ConstIsRHS));

if (auto *SOC = dyn_cast<Constant>(SO)) {
  if (ConstIsRHS)
    return ConstantExpr::get(I.getOpcode(), SOC, ConstOperand);
  return ConstantExpr::get(I.getOpcode(), ConstOperand, SOC);
}

Value *Op0 = SO, *Op1 = ConstOperand;
if (!ConstIsRHS)
  std::swap(Op0, Op1);

auto *BO = cast<BinaryOperator>(&I);
Value *RI = Builder.CreateBinOp(BO->getOpcode(), Op0, Op1,
                                SO->getName() + ".op");
auto *FPInst = dyn_cast<Instruction>(RI);
if (FPInst && isa<FPMathOperator>(FPInst))
  FPInst->copyFastMathFlags(BO);
return RI;
1000}

1002Instruction *InstCombinerImpl::FoldOpIntoSelect(Instruction &Op,
                                              SelectInst *SI) {
// Don't modify shared select instructions.
if (!SI->hasOneUse())
  return nullptr;

Value *TV = SI->getTrueValue();
Value *FV = SI->getFalseValue();
if (!(isa<Constant>(TV) || isa<Constant>(FV)))
  return nullptr;

// Bool selects with constant operands can be folded to logical ops.
if (SI->getType()->isIntOrIntVectorTy(1))
  return nullptr;

// If it's a bitcast involving vectors, make sure it has the same number of
// elements on both sides.
if (auto *BC = dyn_cast<BitCastInst>(&Op)) {
  VectorType *DestTy = dyn_cast<VectorType>(BC->getDestTy());
  VectorType *SrcTy = dyn_cast<VectorType>(BC->getSrcTy());

  // Verify that either both or neither are vectors.
  if ((SrcTy == nullptr) != (DestTy == nullptr))
    return nullptr;

  // If vectors, verify that they have the same number of elements.
  if (SrcTy && SrcTy->getElementCount() != DestTy->getElementCount())
    return nullptr;
}

// Test if a CmpInst instruction is used exclusively by a select as
// part of a minimum or maximum operation. If so, refrain from doing
// any other folding. This helps out other analyses which understand
// non-obfuscated minimum and maximum idioms, such as ScalarEvolution
// and CodeGen. And in this case, at least one of the comparison
// operands has at least one user besides the compare (the select),
// which would often largely negate the benefit of folding anyway.
if (auto *CI = dyn_cast<CmpInst>(SI->getCondition())) {
  if (CI->hasOneUse()) {
    Value *Op0 = CI->getOperand(0), *Op1 = CI->getOperand(1);

    // FIXME: This is a hack to avoid infinite looping with min/max patterns.
    //        We have to ensure that vector constants that only differ with
    //        undef elements are treated as equivalent.
    auto areLooselyEqual = [](Value *A, Value *B) {
      if (A == B)
        return true;

      // Test for vector constants.
      Constant *ConstA, *ConstB;
      if (!match(A, m_Constant(ConstA)) || !match(B, m_Constant(ConstB)))
        return false;

      // TODO: Deal with FP constants?
      if (!A->getType()->isIntOrIntVectorTy() || A->getType() != B->getType())
        return false;

      // Compare for equality including undefs as equal.
      auto *Cmp = ConstantExpr::getCompare(ICmpInst::ICMP_EQ, ConstA, ConstB);
      const APInt *C;
      return match(Cmp, m_APIntAllowUndef(C)) && C->isOneValue();
    };

    if ((areLooselyEqual(TV, Op0) && areLooselyEqual(FV, Op1)) ||
        (areLooselyEqual(FV, Op0) && areLooselyEqual(TV, Op1)))
      return nullptr;
  }
}

Value *NewTV = foldOperationIntoSelectOperand(Op, TV, Builder);
Value *NewFV = foldOperationIntoSelectOperand(Op, FV, Builder);
return SelectInst::Create(SI->getCondition(), NewTV, NewFV, "", nullptr, SI);
1074}

1076static Value *foldOperationIntoPhiValue(BinaryOperator *I, Value *InV,
                                      InstCombiner::BuilderTy &Builder) {
bool ConstIsRHS = isa<Constant>(I->getOperand(1));
Constant *C = cast<Constant>(I->getOperand(ConstIsRHS));

if (auto *InC = dyn_cast<Constant>(InV)) {
  if (ConstIsRHS)
    return ConstantExpr::get(I->getOpcode(), InC, C);
  return ConstantExpr::get(I->getOpcode(), C, InC);
}

Value *Op0 = InV, *Op1 = C;
if (!ConstIsRHS)
  std::swap(Op0, Op1);

Value *RI = Builder.CreateBinOp(I->getOpcode(), Op0, Op1, "phi.bo");
auto *FPInst = dyn_cast<Instruction>(RI);
if (FPInst && isa<FPMathOperator>(FPInst))
  FPInst->copyFastMathFlags(I);
return RI;
1096}

1098Instruction *InstCombinerImpl::foldOpIntoPhi(Instruction &I, PHINode *PN) {
unsigned NumPHIValues = PN->getNumIncomingValues();
if (NumPHIValues == 0)
  return nullptr;

// We normally only transform phis with a single use.  However, if a PHI has
// multiple uses and they are all the same operation, we can fold *all* of the
// uses into the PHI.
if (!PN->hasOneUse()) {
  // Walk the use list for the instruction, comparing them to I.
  for (User *U : PN->users()) {
    Instruction *UI = cast<Instruction>(U);
    if (UI != &I && !I.isIdenticalTo(UI))
      return nullptr;
  }
  // Otherwise, we can replace *all* users with the new PHI we form.
}

// Check to see if all of the operands of the PHI are simple constants
// (constantint/constantfp/undef).  If there is one non-constant value,
// remember the BB it is in.  If there is more than one or if *it* is a PHI,
// bail out.  We don't do arbitrary constant expressions here because moving
// their computation can be expensive without a cost model.
BasicBlock *NonConstBB = nullptr;
for (unsigned i = 0; i != NumPHIValues; ++i) {
  Value *InVal = PN->getIncomingValue(i);
  // If I is a freeze instruction, count undef as a non-constant.
  if (match(InVal, m_ImmConstant()) &&
      (!isa<FreezeInst>(I) || isGuaranteedNotToBeUndefOrPoison(InVal)))
    continue;

  if (isa<PHINode>(InVal)) return nullptr;  // Itself a phi.
  if (NonConstBB) return nullptr;  // More than one non-const value.

  NonConstBB = PN->getIncomingBlock(i);

  // If the InVal is an invoke at the end of the pred block, then we can't
  // insert a computation after it without breaking the edge.
  if (isa<InvokeInst>(InVal))
    if (cast<Instruction>(InVal)->getParent() == NonConstBB)
      return nullptr;

  // If the incoming non-constant value is in I's block, we will remove one
  // instruction, but insert another equivalent one, leading to infinite
  // instcombine.
  if (isPotentiallyReachable(I.getParent(), NonConstBB, nullptr, &DT, LI))
    return nullptr;
}

// If there is exactly one non-constant value, we can insert a copy of the
// operation in that block.  However, if this is a critical edge, we would be
// inserting the computation on some other paths (e.g. inside a loop).  Only
// do this if the pred block is unconditionally branching into the phi block.
// Also, make sure that the pred block is not dead code.
if (NonConstBB != nullptr) {
  BranchInst *BI = dyn_cast<BranchInst>(NonConstBB->getTerminator());
  if (!BI || !BI->isUnconditional() || !DT.isReachableFromEntry(NonConstBB))
    return nullptr;
}

// Okay, we can do the transformation: create the new PHI node.
PHINode *NewPN = PHINode::Create(I.getType(), PN->getNumIncomingValues());
InsertNewInstBefore(NewPN, *PN);
NewPN->takeName(PN);

// If we are going to have to insert a new computation, do so right before the
// predecessor's terminator.
if (NonConstBB)
  Builder.SetInsertPoint(NonConstBB->getTerminator());

// Next, add all of the operands to the PHI.
if (SelectInst *SI = dyn_cast<SelectInst>(&I)) {
  // We only currently try to fold the condition of a select when it is a phi,
  // not the true/false values.
  Value *TrueV = SI->getTrueValue();
  Value *FalseV = SI->getFalseValue();
  BasicBlock *PhiTransBB = PN->getParent();
  for (unsigned i = 0; i != NumPHIValues; ++i) {
    BasicBlock *ThisBB = PN->getIncomingBlock(i);
    Value *TrueVInPred = TrueV->DoPHITranslation(PhiTransBB, ThisBB);
    Value *FalseVInPred = FalseV->DoPHITranslation(PhiTransBB, ThisBB);
    Value *InV = nullptr;
    // Beware of ConstantExpr:  it may eventually evaluate to getNullValue,
    // even if currently isNullValue gives false.
    Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i));
    // For vector constants, we cannot use isNullValue to fold into
    // FalseVInPred versus TrueVInPred. When we have individual nonzero
    // elements in the vector, we will incorrectly fold InC to
    // `TrueVInPred`.
    if (InC && isa<ConstantInt>(InC))
      InV = InC->isNullValue() ? FalseVInPred : TrueVInPred;
    else {
      // Generate the select in the same block as PN's current incoming block.
      // Note: ThisBB need not be the NonConstBB because vector constants
      // which are constants by definition are handled here.
      // FIXME: This can lead to an increase in IR generation because we might
      // generate selects for vector constant phi operand, that could not be
      // folded to TrueVInPred or FalseVInPred as done for ConstantInt. For
      // non-vector phis, this transformation was always profitable because
      // the select would be generated exactly once in the NonConstBB.
      Builder.SetInsertPoint(ThisBB->getTerminator());
      InV = Builder.CreateSelect(PN->getIncomingValue(i), TrueVInPred,
                                 FalseVInPred, "phi.sel");
    }
    NewPN->addIncoming(InV, ThisBB);
  }
} else if (CmpInst *CI = dyn_cast<CmpInst>(&I)) {
  Constant *C = cast<Constant>(I.getOperand(1));
  for (unsigned i = 0; i != NumPHIValues; ++i) {
    Value *InV = nullptr;
    if (auto *InC = dyn_cast<Constant>(PN->getIncomingValue(i)))
      InV = ConstantExpr::getCompare(CI->getPredicate(), InC, C);
    else
      InV = Builder.CreateCmp(CI->getPredicate(), PN->getIncomingValue(i),
                              C, "phi.cmp");
    NewPN->addIncoming(InV, PN->getIncomingBlock(i));
  }
} else if (auto *BO = dyn_cast<BinaryOperator>(&I)) {
  for (unsigned i = 0; i != NumPHIValues; ++i) {
    Value *InV = foldOperationIntoPhiValue(BO, PN->getIncomingValue(i),
                                           Builder);
    NewPN->addIncoming(InV, PN->getIncomingBlock(i));
  }
} else if (isa<FreezeInst>(&I)) {
  for (unsigned i = 0; i != NumPHIValues; ++i) {
    Value *InV;
    if (NonConstBB == PN->getIncomingBlock(i))
      InV = Builder.CreateFreeze(PN->getIncomingValue(i), "phi.fr");
    else
      InV = PN->getIncomingValue(i);
    NewPN->addIncoming(InV, PN->getIncomingBlock(i));
  }
} else {
  CastInst *CI = cast<CastInst>(&I);
  Type *RetTy = CI->getType();
  for (unsigned i = 0; i != NumPHIValues; ++i) {
    Value *InV;
    if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i)))
      InV = ConstantExpr::getCast(CI->getOpcode(), InC, RetTy);
    else
      InV = Builder.CreateCast(CI->getOpcode(), PN->getIncomingValue(i),
                               I.getType(), "phi.cast");
    NewPN->addIncoming(InV, PN->getIncomingBlock(i));
  }
}

for (User *U : make_early_inc_range(PN->users())) {
  Instruction *User = cast<Instruction>(U);
  if (User == &I) continue;
  replaceInstUsesWith(*User, NewPN);
  eraseInstFromFunction(*User);
}
return replaceInstUsesWith(I, NewPN);
1251}

1253Instruction *InstCombinerImpl::foldBinOpIntoSelectOrPhi(BinaryOperator &I) {
if (!isa<Constant>(I.getOperand(1)))
  return nullptr;

if (auto *Sel = dyn_cast<SelectInst>(I.getOperand(0))) {
  if (Instruction *NewSel = FoldOpIntoSelect(I, Sel))
    return NewSel;
} else if (auto *PN = dyn_cast<PHINode>(I.getOperand(0))) {
  if (Instruction *NewPhi = foldOpIntoPhi(I, PN))
    return NewPhi;
}
return nullptr;
1265}

1267/// Given a pointer type and a constant offset, determine whether or not there
1268/// is a sequence of GEP indices into the pointed type that will land us at the
1269/// specified offset. If so, fill them into NewIndices and return the resultant
1270/// element type, otherwise return null.
1271Type *
1272InstCombinerImpl::FindElementAtOffset(PointerType *PtrTy, int64_t Offset,
                                    SmallVectorImpl<Value *> &NewIndices) {
Type *Ty = PtrTy->getElementType();
if (!Ty->isSized())
  return nullptr;

// Start with the index over the outer type.  Note that the type size
// might be zero (even if the offset isn't zero) if the indexed type
// is something like [0 x {int, int}]
Type *IndexTy = DL.getIndexType(PtrTy);
int64_t FirstIdx = 0;
if (int64_t TySize = DL.getTypeAllocSize(Ty)) {
  FirstIdx = Offset/TySize;
  Offset -= FirstIdx*TySize;

  // Handle hosts where % returns negative instead of values [0..TySize).
  if (Offset < 0) {
    --FirstIdx;
    Offset += TySize;
    assert(Offset >= 0)(static_cast <bool> (Offset >= 0) ? void (0) : __assert_fail
 ("Offset >= 0", "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1291, __extension__ __PRETTY_FUNCTION__));
  }
  assert((uint64_t)Offset < (uint64_t)TySize && "Out of range offset")(static_cast <bool> ((uint64_t)Offset < (uint64_t)TySize
 && "Out of range offset") ? void (0) : __assert_fail
 ("(uint64_t)Offset < (uint64_t)TySize && \"Out of range offset\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1293, __extension__ __PRETTY_FUNCTION__));
}

NewIndices.push_back(ConstantInt::get(IndexTy, FirstIdx));

// Index into the types.  If we fail, set OrigBase to null.
while (Offset) {
  // Indexing into tail padding between struct/array elements.
  if (uint64_t(Offset * 8) >= DL.getTypeSizeInBits(Ty))
    return nullptr;

  if (StructType *STy = dyn_cast<StructType>(Ty)) {
    const StructLayout *SL = DL.getStructLayout(STy);
    assert(Offset < (int64_t)SL->getSizeInBytes() &&(static_cast <bool> (Offset < (int64_t)SL->getSizeInBytes
() && "Offset must stay within the indexed type") ? void
 (0) : __assert_fail ("Offset < (int64_t)SL->getSizeInBytes() && \"Offset must stay within the indexed type\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1307, __extension__ __PRETTY_FUNCTION__))
           "Offset must stay within the indexed type")(static_cast <bool> (Offset < (int64_t)SL->getSizeInBytes
() && "Offset must stay within the indexed type") ? void
 (0) : __assert_fail ("Offset < (int64_t)SL->getSizeInBytes() && \"Offset must stay within the indexed type\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1307, __extension__ __PRETTY_FUNCTION__));

    unsigned Elt = SL->getElementContainingOffset(Offset);
    NewIndices.push_back(ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
                                          Elt));

    Offset -= SL->getElementOffset(Elt);
    Ty = STy->getElementType(Elt);
  } else if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
    uint64_t EltSize = DL.getTypeAllocSize(AT->getElementType());
    assert(EltSize && "Cannot index into a zero-sized array")(static_cast <bool> (EltSize && "Cannot index into a zero-sized array"
) ? void (0) : __assert_fail ("EltSize && \"Cannot index into a zero-sized array\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1317, __extension__ __PRETTY_FUNCTION__));
    NewIndices.push_back(ConstantInt::get(IndexTy,Offset/EltSize));
    Offset %= EltSize;
    Ty = AT->getElementType();
  } else {
    // Otherwise, we can't index into the middle of this atomic type, bail.
    return nullptr;
  }
}

return Ty;
1328}

1330static bool shouldMergeGEPs(GEPOperator &GEP, GEPOperator &Src) {
// If this GEP has only 0 indices, it is the same pointer as
// Src. If Src is not a trivial GEP too, don't combine
// the indices.
if (GEP.hasAllZeroIndices() && !Src.hasAllZeroIndices() &&
    !Src.hasOneUse())
  return false;
return true;
1338}

1340/// Return a value X such that Val = X * Scale, or null if none.
1341/// If the multiplication is known not to overflow, then NoSignedWrap is set.
1342Value *InstCombinerImpl::Descale(Value *Val, APInt Scale, bool &NoSignedWrap) {
assert(isa<IntegerType>(Val->getType()) && "Can only descale integers!")(static_cast <bool> (isa<IntegerType>(Val->getType
()) && "Can only descale integers!") ? void (0) : __assert_fail
 ("isa<IntegerType>(Val->getType()) && \"Can only descale integers!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1343, __extension__ __PRETTY_FUNCTION__));
assert(cast<IntegerType>(Val->getType())->getBitWidth() ==(static_cast <bool> (cast<IntegerType>(Val->getType
())->getBitWidth() == Scale.getBitWidth() && "Scale not compatible with value!"
) ? void (0) : __assert_fail ("cast<IntegerType>(Val->getType())->getBitWidth() == Scale.getBitWidth() && \"Scale not compatible with value!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1345, __extension__ __PRETTY_FUNCTION__))
       Scale.getBitWidth() && "Scale not compatible with value!")(static_cast <bool> (cast<IntegerType>(Val->getType
())->getBitWidth() == Scale.getBitWidth() && "Scale not compatible with value!"
) ? void (0) : __assert_fail ("cast<IntegerType>(Val->getType())->getBitWidth() == Scale.getBitWidth() && \"Scale not compatible with value!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1345, __extension__ __PRETTY_FUNCTION__));

// If Val is zero or Scale is one then Val = Val * Scale.
if (match(Val, m_Zero()) || Scale == 1) {
  NoSignedWrap = true;
  return Val;
}

// If Scale is zero then it does not divide Val.
if (Scale.isMinValue())
  return nullptr;

// Look through chains of multiplications, searching for a constant that is
// divisible by Scale.  For example, descaling X*(Y*(Z*4)) by a factor of 4
// will find the constant factor 4 and produce X*(Y*Z).  Descaling X*(Y*8) by
// a factor of 4 will produce X*(Y*2).  The principle of operation is to bore
// down from Val:
//
//     Val = M1 * X          ||   Analysis starts here and works down
//      M1 = M2 * Y          ||   Doesn't descend into terms with more
//      M2 =  Z * 4          \/   than one use
//
// Then to modify a term at the bottom:
//
//     Val = M1 * X
//      M1 =  Z * Y          ||   Replaced M2 with Z
//
// Then to work back up correcting nsw flags.

// Op - the term we are currently analyzing.  Starts at Val then drills down.
// Replaced with its descaled value before exiting from the drill down loop.
Value *Op = Val;

// Parent - initially null, but after drilling down notes where Op came from.
// In the example above, Parent is (Val, 0) when Op is M1, because M1 is the
// 0'th operand of Val.
std::pair<Instruction *, unsigned> Parent;

// Set if the transform requires a descaling at deeper levels that doesn't
// overflow.
bool RequireNoSignedWrap = false;

// Log base 2 of the scale. Negative if not a power of 2.
int32_t logScale = Scale.exactLogBase2();

for (;; Op = Parent.first->getOperand(Parent.second)) { // Drill down
  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
    // If Op is a constant divisible by Scale then descale to the quotient.
    APInt Quotient(Scale), Remainder(Scale); // Init ensures right bitwidth.
    APInt::sdivrem(CI->getValue(), Scale, Quotient, Remainder);
    if (!Remainder.isMinValue())
      // Not divisible by Scale.
      return nullptr;
    // Replace with the quotient in the parent.
    Op = ConstantInt::get(CI->getType(), Quotient);
    NoSignedWrap = true;
    break;
  }

  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op)) {
    if (BO->getOpcode() == Instruction::Mul) {
      // Multiplication.
      NoSignedWrap = BO->hasNoSignedWrap();
      if (RequireNoSignedWrap && !NoSignedWrap)
        return nullptr;

      // There are three cases for multiplication: multiplication by exactly
      // the scale, multiplication by a constant different to the scale, and
      // multiplication by something else.
      Value *LHS = BO->getOperand(0);
      Value *RHS = BO->getOperand(1);

      if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
        // Multiplication by a constant.
        if (CI->getValue() == Scale) {
          // Multiplication by exactly the scale, replace the multiplication
          // by its left-hand side in the parent.
          Op = LHS;
          break;
        }

        // Otherwise drill down into the constant.
        if (!Op->hasOneUse())
          return nullptr;

        Parent = std::make_pair(BO, 1);
        continue;
      }

      // Multiplication by something else. Drill down into the left-hand side
      // since that's where the reassociate pass puts the good stuff.
      if (!Op->hasOneUse())
        return nullptr;

      Parent = std::make_pair(BO, 0);
      continue;
    }

    if (logScale > 0 && BO->getOpcode() == Instruction::Shl &&
        isa<ConstantInt>(BO->getOperand(1))) {
      // Multiplication by a power of 2.
      NoSignedWrap = BO->hasNoSignedWrap();
      if (RequireNoSignedWrap && !NoSignedWrap)
        return nullptr;

      Value *LHS = BO->getOperand(0);
      int32_t Amt = cast<ConstantInt>(BO->getOperand(1))->
        getLimitedValue(Scale.getBitWidth());
      // Op = LHS << Amt.

      if (Amt == logScale) {
        // Multiplication by exactly the scale, replace the multiplication
        // by its left-hand side in the parent.
        Op = LHS;
        break;
      }
      if (Amt < logScale || !Op->hasOneUse())
        return nullptr;

      // Multiplication by more than the scale.  Reduce the multiplying amount
      // by the scale in the parent.
      Parent = std::make_pair(BO, 1);
      Op = ConstantInt::get(BO->getType(), Amt - logScale);
      break;
    }
  }

  if (!Op->hasOneUse())
    return nullptr;

  if (CastInst *Cast = dyn_cast<CastInst>(Op)) {
    if (Cast->getOpcode() == Instruction::SExt) {
      // Op is sign-extended from a smaller type, descale in the smaller type.
      unsigned SmallSize = Cast->getSrcTy()->getPrimitiveSizeInBits();
      APInt SmallScale = Scale.trunc(SmallSize);
      // Suppose Op = sext X, and we descale X as Y * SmallScale.  We want to
      // descale Op as (sext Y) * Scale.  In order to have
      //   sext (Y * SmallScale) = (sext Y) * Scale
      // some conditions need to hold however: SmallScale must sign-extend to
      // Scale and the multiplication Y * SmallScale should not overflow.
      if (SmallScale.sext(Scale.getBitWidth()) != Scale)
        // SmallScale does not sign-extend to Scale.
        return nullptr;
      assert(SmallScale.exactLogBase2() == logScale)(static_cast <bool> (SmallScale.exactLogBase2() == logScale
) ? void (0) : __assert_fail ("SmallScale.exactLogBase2() == logScale"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1488, __extension__ __PRETTY_FUNCTION__));
      // Require that Y * SmallScale must not overflow.
      RequireNoSignedWrap = true;

      // Drill down through the cast.
      Parent = std::make_pair(Cast, 0);
      Scale = SmallScale;
      continue;
    }

    if (Cast->getOpcode() == Instruction::Trunc) {
      // Op is truncated from a larger type, descale in the larger type.
      // Suppose Op = trunc X, and we descale X as Y * sext Scale.  Then
      //   trunc (Y * sext Scale) = (trunc Y) * Scale
      // always holds.  However (trunc Y) * Scale may overflow even if
      // trunc (Y * sext Scale) does not, so nsw flags need to be cleared
      // from this point up in the expression (see later).
      if (RequireNoSignedWrap)
        return nullptr;

      // Drill down through the cast.
      unsigned LargeSize = Cast->getSrcTy()->getPrimitiveSizeInBits();
      Parent = std::make_pair(Cast, 0);
      Scale = Scale.sext(LargeSize);
      if (logScale + 1 == (int32_t)Cast->getType()->getPrimitiveSizeInBits())
        logScale = -1;
      assert(Scale.exactLogBase2() == logScale)(static_cast <bool> (Scale.exactLogBase2() == logScale)
 ? void (0) : __assert_fail ("Scale.exactLogBase2() == logScale"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1514, __extension__ __PRETTY_FUNCTION__));
      continue;
    }
  }

  // Unsupported expression, bail out.
  return nullptr;
}

// If Op is zero then Val = Op * Scale.
if (match(Op, m_Zero())) {
  NoSignedWrap = true;
  return Op;
}

// We know that we can successfully descale, so from here on we can safely
// modify the IR.  Op holds the descaled version of the deepest term in the
// expression.  NoSignedWrap is 'true' if multiplying Op by Scale is known
// not to overflow.

if (!Parent.first)
  // The expression only had one term.
  return Op;

// Rewrite the parent using the descaled version of its operand.
assert(Parent.first->hasOneUse() && "Drilled down when more than one use!")(static_cast <bool> (Parent.first->hasOneUse() &&
 "Drilled down when more than one use!") ? void (0) : __assert_fail
 ("Parent.first->hasOneUse() && \"Drilled down when more than one use!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1539, __extension__ __PRETTY_FUNCTION__));
assert(Op != Parent.first->getOperand(Parent.second) &&(static_cast <bool> (Op != Parent.first->getOperand(
Parent.second) && "Descaling was a no-op?") ? void (0
) : __assert_fail ("Op != Parent.first->getOperand(Parent.second) && \"Descaling was a no-op?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1541, __extension__ __PRETTY_FUNCTION__))
       "Descaling was a no-op?")(static_cast <bool> (Op != Parent.first->getOperand(
Parent.second) && "Descaling was a no-op?") ? void (0
) : __assert_fail ("Op != Parent.first->getOperand(Parent.second) && \"Descaling was a no-op?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1541, __extension__ __PRETTY_FUNCTION__));
replaceOperand(*Parent.first, Parent.second, Op);
Worklist.push(Parent.first);

// Now work back up the expression correcting nsw flags.  The logic is based
// on the following observation: if X * Y is known not to overflow as a signed
// multiplication, and Y is replaced by a value Z with smaller absolute value,
// then X * Z will not overflow as a signed multiplication either.  As we work
// our way up, having NoSignedWrap 'true' means that the descaled value at the
// current level has strictly smaller absolute value than the original.
Instruction *Ancestor = Parent.first;
do {
  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Ancestor)) {
    // If the multiplication wasn't nsw then we can't say anything about the
    // value of the descaled multiplication, and we have to clear nsw flags
    // from this point on up.
    bool OpNoSignedWrap = BO->hasNoSignedWrap();
    NoSignedWrap &= OpNoSignedWrap;
    if (NoSignedWrap != OpNoSignedWrap) {
      BO->setHasNoSignedWrap(NoSignedWrap);
      Worklist.push(Ancestor);
    }
  } else if (Ancestor->getOpcode() == Instruction::Trunc) {
    // The fact that the descaled input to the trunc has smaller absolute
    // value than the original input doesn't tell us anything useful about
    // the absolute values of the truncations.
    NoSignedWrap = false;
  }
  assert((Ancestor->getOpcode() != Instruction::SExt || NoSignedWrap) &&(static_cast <bool> ((Ancestor->getOpcode() != Instruction
::SExt || NoSignedWrap) && "Failed to keep proper track of nsw flags while drilling down?"
) ? void (0) : __assert_fail ("(Ancestor->getOpcode() != Instruction::SExt || NoSignedWrap) && \"Failed to keep proper track of nsw flags while drilling down?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1570, __extension__ __PRETTY_FUNCTION__))
         "Failed to keep proper track of nsw flags while drilling down?")(static_cast <bool> ((Ancestor->getOpcode() != Instruction
::SExt || NoSignedWrap) && "Failed to keep proper track of nsw flags while drilling down?"
) ? void (0) : __assert_fail ("(Ancestor->getOpcode() != Instruction::SExt || NoSignedWrap) && \"Failed to keep proper track of nsw flags while drilling down?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1570, __extension__ __PRETTY_FUNCTION__));

  if (Ancestor == Val)
    // Got to the top, all done!
    return Val;

  // Move up one level in the expression.
  assert(Ancestor->hasOneUse() && "Drilled down when more than one use!")(static_cast <bool> (Ancestor->hasOneUse() &&
 "Drilled down when more than one use!") ? void (0) : __assert_fail
 ("Ancestor->hasOneUse() && \"Drilled down when more than one use!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1577, __extension__ __PRETTY_FUNCTION__));
  Ancestor = Ancestor->user_back();
} while (true);
1580}

1582Instruction *InstCombinerImpl::foldVectorBinop(BinaryOperator &Inst) {
if (!isa<VectorType>(Inst.getType()))
  return nullptr;

BinaryOperator::BinaryOps Opcode = Inst.getOpcode();
Value *LHS = Inst.getOperand(0), *RHS = Inst.getOperand(1);
assert(cast<VectorType>(LHS->getType())->getElementCount() ==(static_cast <bool> (cast<VectorType>(LHS->getType
())->getElementCount() == cast<VectorType>(Inst.getType
())->getElementCount()) ? void (0) : __assert_fail ("cast<VectorType>(LHS->getType())->getElementCount() == cast<VectorType>(Inst.getType())->getElementCount()"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1589, __extension__ __PRETTY_FUNCTION__))
       cast<VectorType>(Inst.getType())->getElementCount())(static_cast <bool> (cast<VectorType>(LHS->getType
())->getElementCount() == cast<VectorType>(Inst.getType
())->getElementCount()) ? void (0) : __assert_fail ("cast<VectorType>(LHS->getType())->getElementCount() == cast<VectorType>(Inst.getType())->getElementCount()"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1589, __extension__ __PRETTY_FUNCTION__));
assert(cast<VectorType>(RHS->getType())->getElementCount() ==(static_cast <bool> (cast<VectorType>(RHS->getType
())->getElementCount() == cast<VectorType>(Inst.getType
())->getElementCount()) ? void (0) : __assert_fail ("cast<VectorType>(RHS->getType())->getElementCount() == cast<VectorType>(Inst.getType())->getElementCount()"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1591, __extension__ __PRETTY_FUNCTION__))
       cast<VectorType>(Inst.getType())->getElementCount())(static_cast <bool> (cast<VectorType>(RHS->getType
())->getElementCount() == cast<VectorType>(Inst.getType
())->getElementCount()) ? void (0) : __assert_fail ("cast<VectorType>(RHS->getType())->getElementCount() == cast<VectorType>(Inst.getType())->getElementCount()"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1591, __extension__ __PRETTY_FUNCTION__));

// If both operands of the binop are vector concatenations, then perform the
// narrow binop on each pair of the source operands followed by concatenation
// of the results.
Value *L0, *L1, *R0, *R1;
ArrayRef<int> Mask;
if (match(LHS, m_Shuffle(m_Value(L0), m_Value(L1), m_Mask(Mask))) &&
    match(RHS, m_Shuffle(m_Value(R0), m_Value(R1), m_SpecificMask(Mask))) &&
    LHS->hasOneUse() && RHS->hasOneUse() &&
    cast<ShuffleVectorInst>(LHS)->isConcat() &&
    cast<ShuffleVectorInst>(RHS)->isConcat()) {
  // This transform does not have the speculative execution constraint as
  // below because the shuffle is a concatenation. The new binops are
  // operating on exactly the same elements as the existing binop.
  // TODO: We could ease the mask requirement to allow different undef lanes,
  //       but that requires an analysis of the binop-with-undef output value.
  Value *NewBO0 = Builder.CreateBinOp(Opcode, L0, R0);
  if (auto *BO = dyn_cast<BinaryOperator>(NewBO0))
    BO->copyIRFlags(&Inst);
  Value *NewBO1 = Builder.CreateBinOp(Opcode, L1, R1);
  if (auto *BO = dyn_cast<BinaryOperator>(NewBO1))
    BO->copyIRFlags(&Inst);
  return new ShuffleVectorInst(NewBO0, NewBO1, Mask);
}

// It may not be safe to reorder shuffles and things like div, urem, etc.
// because we may trap when executing those ops on unknown vector elements.
// See PR20059.
if (!isSafeToSpeculativelyExecute(&Inst))
  return nullptr;

auto createBinOpShuffle = [&](Value *X, Value *Y, ArrayRef<int> M) {
  Value *XY = Builder.CreateBinOp(Opcode, X, Y);
  if (auto *BO = dyn_cast<BinaryOperator>(XY))
    BO->copyIRFlags(&Inst);
  return new ShuffleVectorInst(XY, UndefValue::get(XY->getType()), M);
};

// If both arguments of the binary operation are shuffles that use the same
// mask and shuffle within a single vector, move the shuffle after the binop.
Value *V1, *V2;
if (match(LHS, m_Shuffle(m_Value(V1), m_Undef(), m_Mask(Mask))) &&
    match(RHS, m_Shuffle(m_Value(V2), m_Undef(), m_SpecificMask(Mask))) &&
    V1->getType() == V2->getType() &&
    (LHS->hasOneUse() || RHS->hasOneUse() || LHS == RHS)) {
  // Op(shuffle(V1, Mask), shuffle(V2, Mask)) -> shuffle(Op(V1, V2), Mask)
  return createBinOpShuffle(V1, V2, Mask);
}

// If both arguments of a commutative binop are select-shuffles that use the
// same mask with commuted operands, the shuffles are unnecessary.
if (Inst.isCommutative() &&
    match(LHS, m_Shuffle(m_Value(V1), m_Value(V2), m_Mask(Mask))) &&
    match(RHS,
          m_Shuffle(m_Specific(V2), m_Specific(V1), m_SpecificMask(Mask)))) {
  auto *LShuf = cast<ShuffleVectorInst>(LHS);
  auto *RShuf = cast<ShuffleVectorInst>(RHS);
  // TODO: Allow shuffles that contain undefs in the mask?
  //       That is legal, but it reduces undef knowledge.
  // TODO: Allow arbitrary shuffles by shuffling after binop?
  //       That might be legal, but we have to deal with poison.
  if (LShuf->isSelect() &&
      !is_contained(LShuf->getShuffleMask(), UndefMaskElem) &&
      RShuf->isSelect() &&
      !is_contained(RShuf->getShuffleMask(), UndefMaskElem)) {
    // Example:
    // LHS = shuffle V1, V2, <0, 5, 6, 3>
    // RHS = shuffle V2, V1, <0, 5, 6, 3>
    // LHS + RHS --> (V10+V20, V21+V11, V22+V12, V13+V23) --> V1 + V2
    Instruction *NewBO = BinaryOperator::Create(Opcode, V1, V2);
    NewBO->copyIRFlags(&Inst);
    return NewBO;
  }
}

// If one argument is a shuffle within one vector and the other is a constant,
// try moving the shuffle after the binary operation. This canonicalization
// intends to move shuffles closer to other shuffles and binops closer to
// other binops, so they can be folded. It may also enable demanded elements
// transforms.
Constant *C;
auto *InstVTy = dyn_cast<FixedVectorType>(Inst.getType());
if (InstVTy &&
    match(&Inst,
          m_c_BinOp(m_OneUse(m_Shuffle(m_Value(V1), m_Undef(), m_Mask(Mask))),
                    m_ImmConstant(C))) &&
    cast<FixedVectorType>(V1->getType())->getNumElements() <=
        InstVTy->getNumElements()) {
  assert(InstVTy->getScalarType() == V1->getType()->getScalarType() &&(static_cast <bool> (InstVTy->getScalarType() == V1->
getType()->getScalarType() && "Shuffle should not change scalar type"
) ? void (0) : __assert_fail ("InstVTy->getScalarType() == V1->getType()->getScalarType() && \"Shuffle should not change scalar type\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1681, __extension__ __PRETTY_FUNCTION__))
         "Shuffle should not change scalar type")(static_cast <bool> (InstVTy->getScalarType() == V1->
getType()->getScalarType() && "Shuffle should not change scalar type"
) ? void (0) : __assert_fail ("InstVTy->getScalarType() == V1->getType()->getScalarType() && \"Shuffle should not change scalar type\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1681, __extension__ __PRETTY_FUNCTION__));

  // Find constant NewC that has property:
  //   shuffle(NewC, ShMask) = C
  // If such constant does not exist (example: ShMask=<0,0> and C=<1,2>)
  // reorder is not possible. A 1-to-1 mapping is not required. Example:
  // ShMask = <1,1,2,2> and C = <5,5,6,6> --> NewC = <undef,5,6,undef>
  bool ConstOp1 = isa<Constant>(RHS);
  ArrayRef<int> ShMask = Mask;
  unsigned SrcVecNumElts =
      cast<FixedVectorType>(V1->getType())->getNumElements();
  UndefValue *UndefScalar = UndefValue::get(C->getType()->getScalarType());
  SmallVector<Constant *, 16> NewVecC(SrcVecNumElts, UndefScalar);
  bool MayChange = true;
  unsigned NumElts = InstVTy->getNumElements();
  for (unsigned I = 0; I < NumElts; ++I) {
    Constant *CElt = C->getAggregateElement(I);
    if (ShMask[I] >= 0) {
      assert(ShMask[I] < (int)NumElts && "Not expecting narrowing shuffle")(static_cast <bool> (ShMask[I] < (int)NumElts &&
 "Not expecting narrowing shuffle") ? void (0) : __assert_fail
 ("ShMask[I] < (int)NumElts && \"Not expecting narrowing shuffle\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 1699, __extension__ __PRETTY_FUNCTION__));
      Constant *NewCElt = NewVecC[ShMask[I]];
      // Bail out if:
      // 1. The constant vector contains a constant expression.
      // 2. The shuffle needs an element of the constant vector that can't
      //    be mapped to a new constant vector.
      // 3. This is a widening shuffle that copies elements of V1 into the
      //    extended elements (extending with undef is allowed).
      if (!CElt || (!isa<UndefValue>(NewCElt) && NewCElt != CElt) ||
          I >= SrcVecNumElts) {
        MayChange = false;
        break;
      }
      NewVecC[ShMask[I]] = CElt;
    }
    // If this is a widening shuffle, we must be able to extend with undef
    // elements. If the original binop does not produce an undef in the high
    // lanes, then this transform is not safe.
    // Similarly for undef lanes due to the shuffle mask, we can only
    // transform binops that preserve undef.
    // TODO: We could shuffle those non-undef constant values into the
    //       result by using a constant vector (rather than an undef vector)
    //       as operand 1 of the new binop, but that might be too aggressive
    //       for target-independent shuffle creation.
    if (I >= SrcVecNumElts || ShMask[I] < 0) {
      Constant *MaybeUndef =
          ConstOp1 ? ConstantExpr::get(Opcode, UndefScalar, CElt)
                   : ConstantExpr::get(Opcode, CElt, UndefScalar);
      if (!match(MaybeUndef, m_Undef())) {
        MayChange = false;
        break;
      }
    }
  }
  if (MayChange) {
    Constant *NewC = ConstantVector::get(NewVecC);
    // It may not be safe to execute a binop on a vector with undef elements
    // because the entire instruction can be folded to undef or create poison
    // that did not exist in the original code.
    if (Inst.isIntDivRem() || (Inst.isShift() && ConstOp1))
      NewC = getSafeVectorConstantForBinop(Opcode, NewC, ConstOp1);

    // Op(shuffle(V1, Mask), C) -> shuffle(Op(V1, NewC), Mask)
    // Op(C, shuffle(V1, Mask)) -> shuffle(Op(NewC, V1), Mask)
    Value *NewLHS = ConstOp1 ? V1 : NewC;
    Value *NewRHS = ConstOp1 ? NewC : V1;
    return createBinOpShuffle(NewLHS, NewRHS, Mask);
  }
}

// Try to reassociate to sink a splat shuffle after a binary operation.
if (Inst.isAssociative() && Inst.isCommutative()) {
  // Canonicalize shuffle operand as LHS.
  if (isa<ShuffleVectorInst>(RHS))
    std::swap(LHS, RHS);

  Value *X;
  ArrayRef<int> MaskC;
  int SplatIndex;
  BinaryOperator *BO;
  if (!match(LHS,
             m_OneUse(m_Shuffle(m_Value(X), m_Undef(), m_Mask(MaskC)))) ||
      !match(MaskC, m_SplatOrUndefMask(SplatIndex)) ||
      X->getType() != Inst.getType() || !match(RHS, m_OneUse(m_BinOp(BO))) ||
      BO->getOpcode() != Opcode)
    return nullptr;

  // FIXME: This may not be safe if the analysis allows undef elements. By
  //        moving 'Y' before the splat shuffle, we are implicitly assuming
  //        that it is not undef/poison at the splat index.
  Value *Y, *OtherOp;
  if (isSplatValue(BO->getOperand(0), SplatIndex)) {
    Y = BO->getOperand(0);
    OtherOp = BO->getOperand(1);
  } else if (isSplatValue(BO->getOperand(1), SplatIndex)) {
    Y = BO->getOperand(1);
    OtherOp = BO->getOperand(0);
  } else {
    return nullptr;
  }

  // X and Y are splatted values, so perform the binary operation on those
  // values followed by a splat followed by the 2nd binary operation:
  // bo (splat X), (bo Y, OtherOp) --> bo (splat (bo X, Y)), OtherOp
  Value *NewBO = Builder.CreateBinOp(Opcode, X, Y);
  SmallVector<int, 8> NewMask(MaskC.size(), SplatIndex);
  Value *NewSplat = Builder.CreateShuffleVector(NewBO, NewMask);
  Instruction *R = BinaryOperator::Create(Opcode, NewSplat, OtherOp);

  // Intersect FMF on both new binops. Other (poison-generating) flags are
  // dropped to be safe.
  if (isa<FPMathOperator>(R)) {
    R->copyFastMathFlags(&Inst);
    R->andIRFlags(BO);
  }
  if (auto *NewInstBO = dyn_cast<BinaryOperator>(NewBO))
    NewInstBO->copyIRFlags(R);
  return R;
}

return nullptr;
1800}

1802/// Try to narrow the width of a binop if at least 1 operand is an extend of
1803/// of a value. This requires a potentially expensive known bits check to make
1804/// sure the narrow op does not overflow.
1805Instruction *InstCombinerImpl::narrowMathIfNoOverflow(BinaryOperator &BO) {
// We need at least one extended operand.
Value *Op0 = BO.getOperand(0), *Op1 = BO.getOperand(1);

// If this is a sub, we swap the operands since we always want an extension
// on the RHS. The LHS can be an extension or a constant.
if (BO.getOpcode() == Instruction::Sub)
  std::swap(Op0, Op1);

Value *X;
bool IsSext = match(Op0, m_SExt(m_Value(X)));
if (!IsSext && !match(Op0, m_ZExt(m_Value(X))))
  return nullptr;

// If both operands are the same extension from the same source type and we
// can eliminate at least one (hasOneUse), this might work.
CastInst::CastOps CastOpc = IsSext ? Instruction::SExt : Instruction::ZExt;
Value *Y;
if (!(match(Op1, m_ZExtOrSExt(m_Value(Y))) && X->getType() == Y->getType() &&
      cast<Operator>(Op1)->getOpcode() == CastOpc &&
      (Op0->hasOneUse() || Op1->hasOneUse()))) {
  // If that did not match, see if we have a suitable constant operand.
  // Truncating and extending must produce the same constant.
  Constant *WideC;
  if (!Op0->hasOneUse() || !match(Op1, m_Constant(WideC)))
    return nullptr;
  Constant *NarrowC = ConstantExpr::getTrunc(WideC, X->getType());
  if (ConstantExpr::getCast(CastOpc, NarrowC, BO.getType()) != WideC)
    return nullptr;
  Y = NarrowC;
}

// Swap back now that we found our operands.
if (BO.getOpcode() == Instruction::Sub)
  std::swap(X, Y);

// Both operands have narrow versions. Last step: the math must not overflow
// in the narrow width.
if (!willNotOverflow(BO.getOpcode(), X, Y, BO, IsSext))
  return nullptr;

// bo (ext X), (ext Y) --> ext (bo X, Y)
// bo (ext X), C       --> ext (bo X, C')
Value *NarrowBO = Builder.CreateBinOp(BO.getOpcode(), X, Y, "narrow");
if (auto *NewBinOp = dyn_cast<BinaryOperator>(NarrowBO)) {
  if (IsSext)
    NewBinOp->setHasNoSignedWrap();
  else
    NewBinOp->setHasNoUnsignedWrap();
}
return CastInst::Create(CastOpc, NarrowBO, BO.getType());
1856}

1858static bool isMergedGEPInBounds(GEPOperator &GEP1, GEPOperator &GEP2) {
// At least one GEP must be inbounds.
if (!GEP1.isInBounds() && !GEP2.isInBounds())
  return false;

return (GEP1.isInBounds() || GEP1.hasAllZeroIndices()) &&
       (GEP2.isInBounds() || GEP2.hasAllZeroIndices());
1865}

1867/// Thread a GEP operation with constant indices through the constant true/false
1868/// arms of a select.
1869static Instruction *foldSelectGEP(GetElementPtrInst &GEP,
                                InstCombiner::BuilderTy &Builder) {
if (!GEP.hasAllConstantIndices())
  return nullptr;

Instruction *Sel;
Value *Cond;
Constant *TrueC, *FalseC;
if (!match(GEP.getPointerOperand(), m_Instruction(Sel)) ||
    !match(Sel,
           m_Select(m_Value(Cond), m_Constant(TrueC), m_Constant(FalseC))))
  return nullptr;

// gep (select Cond, TrueC, FalseC), IndexC --> select Cond, TrueC', FalseC'
// Propagate 'inbounds' and metadata from existing instructions.
// Note: using IRBuilder to create the constants for efficiency.
SmallVector<Value *, 4> IndexC(GEP.indices());
bool IsInBounds = GEP.isInBounds();
Type *Ty = GEP.getSourceElementType();
Value *NewTrueC = IsInBounds ? Builder.CreateInBoundsGEP(Ty, TrueC, IndexC)
                             : Builder.CreateGEP(Ty, TrueC, IndexC);
Value *NewFalseC = IsInBounds ? Builder.CreateInBoundsGEP(Ty, FalseC, IndexC)
                              : Builder.CreateGEP(Ty, FalseC, IndexC);
return SelectInst::Create(Cond, NewTrueC, NewFalseC, "", nullptr, Sel);
1893}

1895Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
SmallVector<Value *, 8> Ops(GEP.operands());
Type *GEPType = GEP.getType();
Type *GEPEltType = GEP.getSourceElementType();
bool IsGEPSrcEleScalable = isa<ScalableVectorType>(GEPEltType);
if (Value *V = SimplifyGEPInst(GEPEltType, Ops, SQ.getWithInstruction(&GEP)))
  return replaceInstUsesWith(GEP, V);

// For vector geps, use the generic demanded vector support.
// Skip if GEP return type is scalable. The number of elements is unknown at
// compile-time.
if (auto *GEPFVTy = dyn_cast<FixedVectorType>(GEPType)) {
  auto VWidth = GEPFVTy->getNumElements();
  APInt UndefElts(VWidth, 0);
  APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
  if (Value *V = SimplifyDemandedVectorElts(&GEP, AllOnesEltMask,
                                            UndefElts)) {
    if (V != &GEP)
      return replaceInstUsesWith(GEP, V);
    return &GEP;
  }

  // TODO: 1) Scalarize splat operands, 2) scalarize entire instruction if
  // possible (decide on canonical form for pointer broadcast), 3) exploit
  // undef elements to decrease demanded bits
}

Value *PtrOp = GEP.getOperand(0);

// Eliminate unneeded casts for indices, and replace indices which displace
// by multiples of a zero size type with zero.
bool MadeChange = false;

// Index width may not be the same width as pointer width.
// Data layout chooses the right type based on supported integer types.
Type *NewScalarIndexTy =
    DL.getIndexType(GEP.getPointerOperandType()->getScalarType());

gep_type_iterator GTI = gep_type_begin(GEP);
for (User::op_iterator I = GEP.op_begin() + 1, E = GEP.op_end(); I != E;
     ++I, ++GTI) {
  // Skip indices into struct types.
  if (GTI.isStruct())
    continue;

  Type *IndexTy = (*I)->getType();
  Type *NewIndexType =
      IndexTy->isVectorTy()
          ? VectorType::get(NewScalarIndexTy,
                            cast<VectorType>(IndexTy)->getElementCount())
          : NewScalarIndexTy;

  // If the element type has zero size then any index over it is equivalent
  // to an index of zero, so replace it with zero if it is not zero already.
  Type *EltTy = GTI.getIndexedType();
  if (EltTy->isSized() && DL.getTypeAllocSize(EltTy).isZero())
    if (!isa<Constant>(*I) || !match(I->get(), m_Zero())) {
      *I = Constant::getNullValue(NewIndexType);
      MadeChange = true;
    }

  if (IndexTy != NewIndexType) {
    // If we are using a wider index than needed for this platform, shrink
    // it to what we need.  If narrower, sign-extend it to what we need.
    // This explicit cast can make subsequent optimizations more obvious.
    *I = Builder.CreateIntCast(*I, NewIndexType, true);
    MadeChange = true;
  }
}
if (MadeChange)
  return &GEP;

// Check to see if the inputs to the PHI node are getelementptr instructions.
if (auto *PN = dyn_cast<PHINode>(PtrOp)) {
  auto *Op1 = dyn_cast<GetElementPtrInst>(PN->getOperand(0));
  if (!Op1)
    return nullptr;

  // Don't fold a GEP into itself through a PHI node. This can only happen
  // through the back-edge of a loop. Folding a GEP into itself means that
  // the value of the previous iteration needs to be stored in the meantime,
  // thus requiring an additional register variable to be live, but not
  // actually achieving anything (the GEP still needs to be executed once per
  // loop iteration).
  if (Op1 == &GEP)
    return nullptr;

  int DI = -1;

  for (auto I = PN->op_begin()+1, E = PN->op_end(); I !=E; ++I) {
    auto *Op2 = dyn_cast<GetElementPtrInst>(*I);
    if (!Op2 || Op1->getNumOperands() != Op2->getNumOperands())
      return nullptr;

    // As for Op1 above, don't try to fold a GEP into itself.
    if (Op2 == &GEP)
      return nullptr;

    // Keep track of the type as we walk the GEP.
    Type *CurTy = nullptr;

    for (unsigned J = 0, F = Op1->getNumOperands(); J != F; ++J) {
      if (Op1->getOperand(J)->getType() != Op2->getOperand(J)->getType())
        return nullptr;

      if (Op1->getOperand(J) != Op2->getOperand(J)) {
        if (DI == -1) {
          // We have not seen any differences yet in the GEPs feeding the
          // PHI yet, so we record this one if it is allowed to be a
          // variable.

          // The first two arguments can vary for any GEP, the rest have to be
          // static for struct slots
          if (J > 1) {
            assert(CurTy && "No current type?")(static_cast <bool> (CurTy && "No current type?"
) ? void (0) : __assert_fail ("CurTy && \"No current type?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2009, __extension__ __PRETTY_FUNCTION__));
            if (CurTy->isStructTy())
              return nullptr;
          }

          DI = J;
        } else {
          // The GEP is different by more than one input. While this could be
          // extended to support GEPs that vary by more than one variable it
          // doesn't make sense since it greatly increases the complexity and
          // would result in an R+R+R addressing mode which no backend
          // directly supports and would need to be broken into several
          // simpler instructions anyway.
          return nullptr;
        }
      }

      // Sink down a layer of the type for the next iteration.
      if (J > 0) {
        if (J == 1) {
          CurTy = Op1->getSourceElementType();
        } else {
          CurTy =
              GetElementPtrInst::getTypeAtIndex(CurTy, Op1->getOperand(J));
        }
      }
    }
  }

  // If not all GEPs are identical we'll have to create a new PHI node.
  // Check that the old PHI node has only one use so that it will get
  // removed.
  if (DI != -1 && !PN->hasOneUse())
    return nullptr;

  auto *NewGEP = cast<GetElementPtrInst>(Op1->clone());
  if (DI == -1) {
    // All the GEPs feeding the PHI are identical. Clone one down into our
    // BB so that it can be merged with the current GEP.
  } else {
    // All the GEPs feeding the PHI differ at a single offset. Clone a GEP
    // into the current block so it can be merged, and create a new PHI to
    // set that index.
    PHINode *NewPN;
    {
      IRBuilderBase::InsertPointGuard Guard(Builder);
      Builder.SetInsertPoint(PN);
      NewPN = Builder.CreatePHI(Op1->getOperand(DI)->getType(),
                                PN->getNumOperands());
    }

    for (auto &I : PN->operands())
      NewPN->addIncoming(cast<GEPOperator>(I)->getOperand(DI),
                         PN->getIncomingBlock(I));

    NewGEP->setOperand(DI, NewPN);
  }

  GEP.getParent()->getInstList().insert(
      GEP.getParent()->getFirstInsertionPt(), NewGEP);
  replaceOperand(GEP, 0, NewGEP);
  PtrOp = NewGEP;
}

// Combine Indices - If the source pointer to this getelementptr instruction
// is a getelementptr instruction, combine the indices of the two
// getelementptr instructions into a single instruction.
if (auto *Src = dyn_cast<GEPOperator>(PtrOp)) {
  if (!shouldMergeGEPs(*cast<GEPOperator>(&GEP), *Src))
    return nullptr;

  if (Src->getNumOperands() == 2 && GEP.getNumOperands() == 2 &&
      Src->hasOneUse()) {
    Value *GO1 = GEP.getOperand(1);
    Value *SO1 = Src->getOperand(1);

    if (LI) {
      // Try to reassociate loop invariant GEP chains to enable LICM.
      if (Loop *L = LI->getLoopFor(GEP.getParent())) {
        // Reassociate the two GEPs if SO1 is variant in the loop and GO1 is
        // invariant: this breaks the dependence between GEPs and allows LICM
        // to hoist the invariant part out of the loop.
        if (L->isLoopInvariant(GO1) && !L->isLoopInvariant(SO1)) {
          // We have to be careful here.
          // We have something like:
          //  %src = getelementptr <ty>, <ty>* %base, <ty> %idx
          //  %gep = getelementptr <ty>, <ty>* %src, <ty> %idx2
          // If we just swap idx & idx2 then we could inadvertantly
          // change %src from a vector to a scalar, or vice versa.
          // Cases:
          //  1) %base a scalar & idx a scalar & idx2 a vector
          //      => Swapping idx & idx2 turns %src into a vector type.
          //  2) %base a scalar & idx a vector & idx2 a scalar
          //      => Swapping idx & idx2 turns %src in a scalar type
          //  3) %base, %idx, and %idx2 are scalars
          //      => %src & %gep are scalars
          //      => swapping idx & idx2 is safe
          //  4) %base a vector
          //      => %src is a vector
          //      => swapping idx & idx2 is safe.
          auto *SO0 = Src->getOperand(0);
          auto *SO0Ty = SO0->getType();
          if (!isa<VectorType>(GEPType) || // case 3
              isa<VectorType>(SO0Ty)) {    // case 4
            Src->setOperand(1, GO1);
            GEP.setOperand(1, SO1);
            return &GEP;
          } else {
            // Case 1 or 2
            // -- have to recreate %src & %gep
            // put NewSrc at same location as %src
            Builder.SetInsertPoint(cast<Instruction>(PtrOp));
            Value *NewSrc =
                Builder.CreateGEP(GEPEltType, SO0, GO1, Src->getName());
            // Propagate 'inbounds' if the new source was not constant-folded.
            if (auto *NewSrcGEPI = dyn_cast<GetElementPtrInst>(NewSrc))
              NewSrcGEPI->setIsInBounds(Src->isInBounds());
            GetElementPtrInst *NewGEP =
                GetElementPtrInst::Create(GEPEltType, NewSrc, {SO1});
            NewGEP->setIsInBounds(GEP.isInBounds());
            return NewGEP;
          }
        }
      }
    }
  }

  // Note that if our source is a gep chain itself then we wait for that
  // chain to be resolved before we perform this transformation.  This
  // avoids us creating a TON of code in some cases.
  if (auto *SrcGEP = dyn_cast<GEPOperator>(Src->getOperand(0)))
    if (SrcGEP->getNumOperands() == 2 && shouldMergeGEPs(*Src, *SrcGEP))
      return nullptr;   // Wait until our source is folded to completion.

  SmallVector<Value*, 8> Indices;

  // Find out whether the last index in the source GEP is a sequential idx.
  bool EndsWithSequential = false;
  for (gep_type_iterator I = gep_type_begin(*Src), E = gep_type_end(*Src);
       I != E; ++I)
    EndsWithSequential = I.isSequential();

  // Can we combine the two pointer arithmetics offsets?
  if (EndsWithSequential) {
    // Replace: gep (gep %P, long B), long A, ...
    // With:    T = long A+B; gep %P, T, ...
    Value *SO1 = Src->getOperand(Src->getNumOperands()-1);
    Value *GO1 = GEP.getOperand(1);

    // If they aren't the same type, then the input hasn't been processed
    // by the loop above yet (which canonicalizes sequential index types to
    // intptr_t).  Just avoid transforming this until the input has been
    // normalized.
    if (SO1->getType() != GO1->getType())
      return nullptr;

    Value *Sum =
        SimplifyAddInst(GO1, SO1, false, false, SQ.getWithInstruction(&GEP));
    // Only do the combine when we are sure the cost after the
    // merge is never more than that before the merge.
    if (Sum == nullptr)
      return nullptr;

    // Update the GEP in place if possible.
    if (Src->getNumOperands() == 2) {
      GEP.setIsInBounds(isMergedGEPInBounds(*Src, *cast<GEPOperator>(&GEP)));
      replaceOperand(GEP, 0, Src->getOperand(0));
      replaceOperand(GEP, 1, Sum);
      return &GEP;
    }
    Indices.append(Src->op_begin()+1, Src->op_end()-1);
    Indices.push_back(Sum);
    Indices.append(GEP.op_begin()+2, GEP.op_end());
  } else if (isa<Constant>(*GEP.idx_begin()) &&
             cast<Constant>(*GEP.idx_begin())->isNullValue() &&
             Src->getNumOperands() != 1) {
    // Otherwise we can do the fold if the first index of the GEP is a zero
    Indices.append(Src->op_begin()+1, Src->op_end());
    Indices.append(GEP.idx_begin()+1, GEP.idx_end());
  }

  if (!Indices.empty())
    return isMergedGEPInBounds(*Src, *cast<GEPOperator>(&GEP))
               ? GetElementPtrInst::CreateInBounds(
                     Src->getSourceElementType(), Src->getOperand(0), Indices,
                     GEP.getName())
               : GetElementPtrInst::Create(Src->getSourceElementType(),
                                           Src->getOperand(0), Indices,
                                           GEP.getName());
}

// Skip if GEP source element type is scalable. The type alloc size is unknown
// at compile-time.
if (GEP.getNumIndices() == 1 && !IsGEPSrcEleScalable) {
  unsigned AS = GEP.getPointerAddressSpace();
  if (GEP.getOperand(1)->getType()->getScalarSizeInBits() ==
      DL.getIndexSizeInBits(AS)) {
    uint64_t TyAllocSize = DL.getTypeAllocSize(GEPEltType).getFixedSize();

    bool Matched = false;
    uint64_t C;
    Value *V = nullptr;
    if (TyAllocSize == 1) {
      V = GEP.getOperand(1);
      Matched = true;
    } else if (match(GEP.getOperand(1),
                     m_AShr(m_Value(V), m_ConstantInt(C)))) {
      if (TyAllocSize == 1ULL << C)
        Matched = true;
    } else if (match(GEP.getOperand(1),
                     m_SDiv(m_Value(V), m_ConstantInt(C)))) {
      if (TyAllocSize == C)
        Matched = true;
    }

    // Canonicalize (gep i8* X, (ptrtoint Y)-(ptrtoint X)) to (bitcast Y), but
    // only if both point to the same underlying object (otherwise provenance
    // is not necessarily retained).
    Value *Y;
    Value *X = GEP.getOperand(0);
    if (Matched &&
        match(V, m_Sub(m_PtrToInt(m_Value(Y)), m_PtrToInt(m_Specific(X)))) &&
        getUnderlyingObject(X) == getUnderlyingObject(Y))
      return CastInst::CreatePointerBitCastOrAddrSpaceCast(Y, GEPType);
  }
}

// We do not handle pointer-vector geps here.
if (GEPType->isVectorTy())
  return nullptr;

// Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
Value *StrippedPtr = PtrOp->stripPointerCasts();
PointerType *StrippedPtrTy = cast<PointerType>(StrippedPtr->getType());

if (StrippedPtr != PtrOp) {
  bool HasZeroPointerIndex = false;
  Type *StrippedPtrEltTy = StrippedPtrTy->getElementType();

  if (auto *C = dyn_cast<ConstantInt>(GEP.getOperand(1)))
    HasZeroPointerIndex = C->isZero();

  // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ...
  // into     : GEP [10 x i8]* X, i32 0, ...
  //
  // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ...
  //           into     : GEP i8* X, ...
  //
  // This occurs when the program declares an array extern like "int X[];"
  if (HasZeroPointerIndex) {
    if (auto *CATy = dyn_cast<ArrayType>(GEPEltType)) {
      // GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ?
      if (CATy->getElementType() == StrippedPtrEltTy) {
        // -> GEP i8* X, ...
        SmallVector<Value *, 8> Idx(drop_begin(GEP.indices()));
        GetElementPtrInst *Res = GetElementPtrInst::Create(
            StrippedPtrEltTy, StrippedPtr, Idx, GEP.getName());
        Res->setIsInBounds(GEP.isInBounds());
        if (StrippedPtrTy->getAddressSpace() == GEP.getAddressSpace())
          return Res;
        // Insert Res, and create an addrspacecast.
        // e.g.,
        // GEP (addrspacecast i8 addrspace(1)* X to [0 x i8]*), i32 0, ...
        // ->
        // %0 = GEP i8 addrspace(1)* X, ...
        // addrspacecast i8 addrspace(1)* %0 to i8*
        return new AddrSpaceCastInst(Builder.Insert(Res), GEPType);
      }

      if (auto *XATy = dyn_cast<ArrayType>(StrippedPtrEltTy)) {
        // GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
        if (CATy->getElementType() == XATy->getElementType()) {
          // -> GEP [10 x i8]* X, i32 0, ...
          // At this point, we know that the cast source type is a pointer
          // to an array of the same type as the destination pointer
          // array.  Because the array type is never stepped over (there
          // is a leading zero) we can fold the cast into this GEP.
          if (StrippedPtrTy->getAddressSpace() == GEP.getAddressSpace()) {
            GEP.setSourceElementType(XATy);
            return replaceOperand(GEP, 0, StrippedPtr);
          }
          // Cannot replace the base pointer directly because StrippedPtr's
          // address space is different. Instead, create a new GEP followed by
          // an addrspacecast.
          // e.g.,
          // GEP (addrspacecast [10 x i8] addrspace(1)* X to [0 x i8]*),
          //   i32 0, ...
          // ->
          // %0 = GEP [10 x i8] addrspace(1)* X, ...
          // addrspacecast i8 addrspace(1)* %0 to i8*
          SmallVector<Value *, 8> Idx(GEP.indices());
          Value *NewGEP =
              GEP.isInBounds()
                  ? Builder.CreateInBoundsGEP(StrippedPtrEltTy, StrippedPtr,
                                              Idx, GEP.getName())
                  : Builder.CreateGEP(StrippedPtrEltTy, StrippedPtr, Idx,
                                      GEP.getName());
          return new AddrSpaceCastInst(NewGEP, GEPType);
        }
      }
    }
  } else if (GEP.getNumOperands() == 2 && !IsGEPSrcEleScalable) {
    // Skip if GEP source element type is scalable. The type alloc size is
    // unknown at compile-time.
    // Transform things like: %t = getelementptr i32*
    // bitcast ([2 x i32]* %str to i32*), i32 %V into:  %t1 = getelementptr [2
    // x i32]* %str, i32 0, i32 %V; bitcast
    if (StrippedPtrEltTy->isArrayTy() &&
        DL.getTypeAllocSize(StrippedPtrEltTy->getArrayElementType()) ==
            DL.getTypeAllocSize(GEPEltType)) {
      Type *IdxType = DL.getIndexType(GEPType);
      Value *Idx[2] = { Constant::getNullValue(IdxType), GEP.getOperand(1) };
      Value *NewGEP =
          GEP.isInBounds()
              ? Builder.CreateInBoundsGEP(StrippedPtrEltTy, StrippedPtr, Idx,
                                          GEP.getName())
              : Builder.CreateGEP(StrippedPtrEltTy, StrippedPtr, Idx,
                                  GEP.getName());

      // V and GEP are both pointer types --> BitCast
      return CastInst::CreatePointerBitCastOrAddrSpaceCast(NewGEP, GEPType);
    }

    // Transform things like:
    // %V = mul i64 %N, 4
    // %t = getelementptr i8* bitcast (i32* %arr to i8*), i32 %V
    // into:  %t1 = getelementptr i32* %arr, i32 %N; bitcast
    if (GEPEltType->isSized() && StrippedPtrEltTy->isSized()) {
      // Check that changing the type amounts to dividing the index by a scale
      // factor.
      uint64_t ResSize = DL.getTypeAllocSize(GEPEltType).getFixedSize();
      uint64_t SrcSize = DL.getTypeAllocSize(StrippedPtrEltTy).getFixedSize();
      if (ResSize && SrcSize % ResSize == 0) {
        Value *Idx = GEP.getOperand(1);
        unsigned BitWidth = Idx->getType()->getPrimitiveSizeInBits();
        uint64_t Scale = SrcSize / ResSize;

        // Earlier transforms ensure that the index has the right type
        // according to Data Layout, which considerably simplifies the
        // logic by eliminating implicit casts.
        assert(Idx->getType() == DL.getIndexType(GEPType) &&(static_cast <bool> (Idx->getType() == DL.getIndexType
(GEPType) && "Index type does not match the Data Layout preferences"
) ? void (0) : __assert_fail ("Idx->getType() == DL.getIndexType(GEPType) && \"Index type does not match the Data Layout preferences\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2350, __extension__ __PRETTY_FUNCTION__))
               "Index type does not match the Data Layout preferences")(static_cast <bool> (Idx->getType() == DL.getIndexType
(GEPType) && "Index type does not match the Data Layout preferences"
) ? void (0) : __assert_fail ("Idx->getType() == DL.getIndexType(GEPType) && \"Index type does not match the Data Layout preferences\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2350, __extension__ __PRETTY_FUNCTION__));

        bool NSW;
        if (Value *NewIdx = Descale(Idx, APInt(BitWidth, Scale), NSW)) {
          // Successfully decomposed Idx as NewIdx * Scale, form a new GEP.
          // If the multiplication NewIdx * Scale may overflow then the new
          // GEP may not be "inbounds".
          Value *NewGEP =
              GEP.isInBounds() && NSW
                  ? Builder.CreateInBoundsGEP(StrippedPtrEltTy, StrippedPtr,
                                              NewIdx, GEP.getName())
                  : Builder.CreateGEP(StrippedPtrEltTy, StrippedPtr, NewIdx,
                                      GEP.getName());

          // The NewGEP must be pointer typed, so must the old one -> BitCast
          return CastInst::CreatePointerBitCastOrAddrSpaceCast(NewGEP,
                                                               GEPType);
        }
      }
    }

    // Similarly, transform things like:
    // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp
    //   (where tmp = 8*tmp2) into:
    // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast
    if (GEPEltType->isSized() && StrippedPtrEltTy->isSized() &&
        StrippedPtrEltTy->isArrayTy()) {
      // Check that changing to the array element type amounts to dividing the
      // index by a scale factor.
      uint64_t ResSize = DL.getTypeAllocSize(GEPEltType).getFixedSize();
      uint64_t ArrayEltSize =
          DL.getTypeAllocSize(StrippedPtrEltTy->getArrayElementType())
              .getFixedSize();
      if (ResSize && ArrayEltSize % ResSize == 0) {
        Value *Idx = GEP.getOperand(1);
        unsigned BitWidth = Idx->getType()->getPrimitiveSizeInBits();
        uint64_t Scale = ArrayEltSize / ResSize;

        // Earlier transforms ensure that the index has the right type
        // according to the Data Layout, which considerably simplifies
        // the logic by eliminating implicit casts.
        assert(Idx->getType() == DL.getIndexType(GEPType) &&(static_cast <bool> (Idx->getType() == DL.getIndexType
(GEPType) && "Index type does not match the Data Layout preferences"
) ? void (0) : __assert_fail ("Idx->getType() == DL.getIndexType(GEPType) && \"Index type does not match the Data Layout preferences\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2392, __extension__ __PRETTY_FUNCTION__))
               "Index type does not match the Data Layout preferences")(static_cast <bool> (Idx->getType() == DL.getIndexType
(GEPType) && "Index type does not match the Data Layout preferences"
) ? void (0) : __assert_fail ("Idx->getType() == DL.getIndexType(GEPType) && \"Index type does not match the Data Layout preferences\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2392, __extension__ __PRETTY_FUNCTION__));

        bool NSW;
        if (Value *NewIdx = Descale(Idx, APInt(BitWidth, Scale), NSW)) {
          // Successfully decomposed Idx as NewIdx * Scale, form a new GEP.
          // If the multiplication NewIdx * Scale may overflow then the new
          // GEP may not be "inbounds".
          Type *IndTy = DL.getIndexType(GEPType);
          Value *Off[2] = {Constant::getNullValue(IndTy), NewIdx};

          Value *NewGEP =
              GEP.isInBounds() && NSW
                  ? Builder.CreateInBoundsGEP(StrippedPtrEltTy, StrippedPtr,
                                              Off, GEP.getName())
                  : Builder.CreateGEP(StrippedPtrEltTy, StrippedPtr, Off,
                                      GEP.getName());
          // The NewGEP must be pointer typed, so must the old one -> BitCast
          return CastInst::CreatePointerBitCastOrAddrSpaceCast(NewGEP,
                                                               GEPType);
        }
      }
    }
  }
}

// addrspacecast between types is canonicalized as a bitcast, then an
// addrspacecast. To take advantage of the below bitcast + struct GEP, look
// through the addrspacecast.
Value *ASCStrippedPtrOp = PtrOp;
if (auto *ASC = dyn_cast<AddrSpaceCastInst>(PtrOp)) {
  //   X = bitcast A addrspace(1)* to B addrspace(1)*
  //   Y = addrspacecast A addrspace(1)* to B addrspace(2)*
  //   Z = gep Y, <...constant indices...>
  // Into an addrspacecasted GEP of the struct.
  if (auto *BC = dyn_cast<BitCastInst>(ASC->getOperand(0)))
    ASCStrippedPtrOp = BC;
}

if (auto *BCI = dyn_cast<BitCastInst>(ASCStrippedPtrOp)) {
  Value *SrcOp = BCI->getOperand(0);
  PointerType *SrcType = cast<PointerType>(BCI->getSrcTy());
  Type *SrcEltType = SrcType->getElementType();

  // GEP directly using the source operand if this GEP is accessing an element
  // of a bitcasted pointer to vector or array of the same dimensions:
  // gep (bitcast <c x ty>* X to [c x ty]*), Y, Z --> gep X, Y, Z
  // gep (bitcast [c x ty]* X to <c x ty>*), Y, Z --> gep X, Y, Z
  auto areMatchingArrayAndVecTypes = [](Type *ArrTy, Type *VecTy,
                                        const DataLayout &DL) {
    auto *VecVTy = cast<FixedVectorType>(VecTy);
    return ArrTy->getArrayElementType() == VecVTy->getElementType() &&
           ArrTy->getArrayNumElements() == VecVTy->getNumElements() &&
           DL.getTypeAllocSize(ArrTy) == DL.getTypeAllocSize(VecTy);
  };
  if (GEP.getNumOperands() == 3 &&
      ((GEPEltType->isArrayTy() && isa<FixedVectorType>(SrcEltType) &&
        areMatchingArrayAndVecTypes(GEPEltType, SrcEltType, DL)) ||
       (isa<FixedVectorType>(GEPEltType) && SrcEltType->isArrayTy() &&
        areMatchingArrayAndVecTypes(SrcEltType, GEPEltType, DL)))) {

    // Create a new GEP here, as using `setOperand()` followed by
    // `setSourceElementType()` won't actually update the type of the
    // existing GEP Value. Causing issues if this Value is accessed when
    // constructing an AddrSpaceCastInst
    Value *NGEP =
        GEP.isInBounds()
            ? Builder.CreateInBoundsGEP(SrcEltType, SrcOp, {Ops[1], Ops[2]})
            : Builder.CreateGEP(SrcEltType, SrcOp, {Ops[1], Ops[2]});
    NGEP->takeName(&GEP);

    // Preserve GEP address space to satisfy users
    if (NGEP->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
      return new AddrSpaceCastInst(NGEP, GEPType);

    return replaceInstUsesWith(GEP, NGEP);
  }

  // See if we can simplify:
  //   X = bitcast A* to B*
  //   Y = gep X, <...constant indices...>
  // into a gep of the original struct. This is important for SROA and alias
  // analysis of unions. If "A" is also a bitcast, wait for A/X to be merged.
  unsigned OffsetBits = DL.getIndexTypeSizeInBits(GEPType);
  APInt Offset(OffsetBits, 0);

  // If the bitcast argument is an allocation, The bitcast is for convertion
  // to actual type of allocation. Removing such bitcasts, results in having
  // GEPs with i8* base and pure byte offsets. That means GEP is not aware of
  // struct or array hierarchy.
  // By avoiding such GEPs, phi translation and MemoryDependencyAnalysis have
  // a better chance to succeed.
  if (!isa<BitCastInst>(SrcOp) && GEP.accumulateConstantOffset(DL, Offset) &&
      !isAllocationFn(SrcOp, &TLI)) {
    // If this GEP instruction doesn't move the pointer, just replace the GEP
    // with a bitcast of the real input to the dest type.
    if (!Offset) {
      // If the bitcast is of an allocation, and the allocation will be
      // converted to match the type of the cast, don't touch this.
      if (isa<AllocaInst>(SrcOp)) {
        // See if the bitcast simplifies, if so, don't nuke this GEP yet.
        if (Instruction *I = visitBitCast(*BCI)) {
          if (I != BCI) {
            I->takeName(BCI);
            BCI->getParent()->getInstList().insert(BCI->getIterator(), I);
            replaceInstUsesWith(*BCI, I);
          }
          return &GEP;
        }
      }

      if (SrcType->getPointerAddressSpace() != GEP.getAddressSpace())
        return new AddrSpaceCastInst(SrcOp, GEPType);
      return new BitCastInst(SrcOp, GEPType);
    }

    // Otherwise, if the offset is non-zero, we need to find out if there is a
    // field at Offset in 'A's type.  If so, we can pull the cast through the
    // GEP.
    SmallVector<Value*, 8> NewIndices;
    if (FindElementAtOffset(SrcType, Offset.getSExtValue(), NewIndices)) {
      Value *NGEP =
          GEP.isInBounds()
              ? Builder.CreateInBoundsGEP(SrcEltType, SrcOp, NewIndices)
              : Builder.CreateGEP(SrcEltType, SrcOp, NewIndices);

      if (NGEP->getType() == GEPType)
        return replaceInstUsesWith(GEP, NGEP);
      NGEP->takeName(&GEP);

      if (NGEP->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
        return new AddrSpaceCastInst(NGEP, GEPType);
      return new BitCastInst(NGEP, GEPType);
    }
  }
}

if (!GEP.isInBounds()) {
  unsigned IdxWidth =
      DL.getIndexSizeInBits(PtrOp->getType()->getPointerAddressSpace());
  APInt BasePtrOffset(IdxWidth, 0);
  Value *UnderlyingPtrOp =
          PtrOp->stripAndAccumulateInBoundsConstantOffsets(DL,
                                                           BasePtrOffset);
  if (auto *AI = dyn_cast<AllocaInst>(UnderlyingPtrOp)) {
    if (GEP.accumulateConstantOffset(DL, BasePtrOffset) &&
        BasePtrOffset.isNonNegative()) {
      APInt AllocSize(
          IdxWidth,
          DL.getTypeAllocSize(AI->getAllocatedType()).getKnownMinSize());
      if (BasePtrOffset.ule(AllocSize)) {
        return GetElementPtrInst::CreateInBounds(
            GEP.getSourceElementType(), PtrOp, makeArrayRef(Ops).slice(1),
            GEP.getName());
      }
    }
  }
}

if (Instruction *R = foldSelectGEP(GEP, Builder))
  return R;

return nullptr;
2554}

2556static bool isNeverEqualToUnescapedAlloc(Value *V, const TargetLibraryInfo *TLI,
                                       Instruction *AI) {
if (isa<ConstantPointerNull>(V))
  return true;
if (auto *LI = dyn_cast<LoadInst>(V))
  return isa<GlobalVariable>(LI->getPointerOperand());
// Two distinct allocations will never be equal.
// We rely on LookThroughBitCast in isAllocLikeFn being false, since looking
// through bitcasts of V can cause
// the result statement below to be true, even when AI and V (ex:
// i8* ->i32* ->i8* of AI) are the same allocations.
return isAllocLikeFn(V, TLI) && V != AI;
2568}

2570static bool isAllocSiteRemovable(Instruction *AI,
                               SmallVectorImpl<WeakTrackingVH> &Users,
                               const TargetLibraryInfo *TLI) {
SmallVector<Instruction*, 4> Worklist;
Worklist.push_back(AI);

do {
  Instruction *PI = Worklist.pop_back_val();
  for (User *U : PI->users()) {
    Instruction *I = cast<Instruction>(U);
    switch (I->getOpcode()) {
    default:
      // Give up the moment we see something we can't handle.
      return false;

    case Instruction::AddrSpaceCast:
    case Instruction::BitCast:
    case Instruction::GetElementPtr:
      Users.emplace_back(I);
      Worklist.push_back(I);
      continue;

    case Instruction::ICmp: {
      ICmpInst *ICI = cast<ICmpInst>(I);
      // We can fold eq/ne comparisons with null to false/true, respectively.
      // We also fold comparisons in some conditions provided the alloc has
      // not escaped (see isNeverEqualToUnescapedAlloc).
      if (!ICI->isEquality())
        return false;
      unsigned OtherIndex = (ICI->getOperand(0) == PI) ? 1 : 0;
      if (!isNeverEqualToUnescapedAlloc(ICI->getOperand(OtherIndex), TLI, AI))
        return false;
      Users.emplace_back(I);
      continue;
    }

    case Instruction::Call:
      // Ignore no-op and store intrinsics.
      if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
        switch (II->getIntrinsicID()) {
        default:
          return false;

        case Intrinsic::memmove:
        case Intrinsic::memcpy:
        case Intrinsic::memset: {
          MemIntrinsic *MI = cast<MemIntrinsic>(II);
          if (MI->isVolatile() || MI->getRawDest() != PI)
            return false;
          LLVM_FALLTHROUGH[[gnu::fallthrough]];
        }
        case Intrinsic::assume:
        case Intrinsic::invariant_start:
        case Intrinsic::invariant_end:
        case Intrinsic::lifetime_start:
        case Intrinsic::lifetime_end:
        case Intrinsic::objectsize:
          Users.emplace_back(I);
          continue;
        case Intrinsic::launder_invariant_group:
        case Intrinsic::strip_invariant_group:
          Users.emplace_back(I);
          Worklist.push_back(I);
          continue;
        }
      }

      if (isFreeCall(I, TLI)) {
        Users.emplace_back(I);
        continue;
      }
      return false;

    case Instruction::Store: {
      StoreInst *SI = cast<StoreInst>(I);
      if (SI->isVolatile() || SI->getPointerOperand() != PI)
        return false;
      Users.emplace_back(I);
      continue;
    }
    }
    llvm_unreachable("missing a return?")::llvm::llvm_unreachable_internal("missing a return?", "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2651);
  }
} while (!Worklist.empty());
return true;
2655}

2657Instruction *InstCombinerImpl::visitAllocSite(Instruction &MI) {
// If we have a malloc call which is only used in any amount of comparisons to
// null and free calls, delete the calls and replace the comparisons with true
// or false as appropriate.

// This is based on the principle that we can substitute our own allocation
// function (which will never return null) rather than knowledge of the
// specific function being called. In some sense this can change the permitted
// outputs of a program (when we convert a malloc to an alloca, the fact that
// the allocation is now on the stack is potentially visible, for example),
// but we believe in a permissible manner.
SmallVector<WeakTrackingVH, 64> Users;

// If we are removing an alloca with a dbg.declare, insert dbg.value calls
// before each store.
SmallVector<DbgVariableIntrinsic *, 8> DVIs;
std::unique_ptr<DIBuilder> DIB;
if (isa<AllocaInst>(MI)) {
  findDbgUsers(DVIs, &MI);
  DIB.reset(new DIBuilder(*MI.getModule(), /*AllowUnresolved=*/false));
}

if (isAllocSiteRemovable(&MI, Users, &TLI)) {
  for (unsigned i = 0, e = Users.size(); i != e; ++i) {
    // Lowering all @llvm.objectsize calls first because they may
    // use a bitcast/GEP of the alloca we are removing.
    if (!Users[i])
     continue;

    Instruction *I = cast<Instruction>(&*Users[i]);

    if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
      if (II->getIntrinsicID() == Intrinsic::objectsize) {
        Value *Result =
            lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/true);
        replaceInstUsesWith(*I, Result);
        eraseInstFromFunction(*I);
        Users[i] = nullptr; // Skip examining in the next loop.
      }
    }
  }
  for (unsigned i = 0, e = Users.size(); i != e; ++i) {
    if (!Users[i])
      continue;

    Instruction *I = cast<Instruction>(&*Users[i]);

    if (ICmpInst *C = dyn_cast<ICmpInst>(I)) {
      replaceInstUsesWith(*C,
                          ConstantInt::get(Type::getInt1Ty(C->getContext()),
                                           C->isFalseWhenEqual()));
    } else if (auto *SI = dyn_cast<StoreInst>(I)) {
      for (auto *DVI : DVIs)
        if (DVI->isAddressOfVariable())
          ConvertDebugDeclareToDebugValue(DVI, SI, *DIB);
    } else {
      // Casts, GEP, or anything else: we're about to delete this instruction,
      // so it can not have any valid uses.
      replaceInstUsesWith(*I, PoisonValue::get(I->getType()));
    }
    eraseInstFromFunction(*I);
  }

  if (InvokeInst *II = dyn_cast<InvokeInst>(&MI)) {
    // Replace invoke with a NOP intrinsic to maintain the original CFG
    Module *M = II->getModule();
    Function *F = Intrinsic::getDeclaration(M, Intrinsic::donothing);
    InvokeInst::Create(F, II->getNormalDest(), II->getUnwindDest(),
                       None, "", II->getParent());
  }

  // Remove debug intrinsics which describe the value contained within the
  // alloca. In addition to removing dbg.{declare,addr} which simply point to
  // the alloca, remove dbg.value(<alloca>, ..., DW_OP_deref)'s as well, e.g.:
  //
  // ```
  //   define void @foo(i32 %0) {
  //     %a = alloca i32                              ; Deleted.
  //     store i32 %0, i32* %a
  //     dbg.value(i32 %0, "arg0")                    ; Not deleted.
  //     dbg.value(i32* %a, "arg0", DW_OP_deref)      ; Deleted.
  //     call void @trivially_inlinable_no_op(i32* %a)
  //     ret void
  //  }
  // ```
  //
  // This may not be required if we stop describing the contents of allocas
  // using dbg.value(<alloca>, ..., DW_OP_deref), but we currently do this in
  // the LowerDbgDeclare utility.
  //
  // If there is a dead store to `%a` in @trivially_inlinable_no_op, the
  // "arg0" dbg.value may be stale after the call. However, failing to remove
  // the DW_OP_deref dbg.value causes large gaps in location coverage.
  for (auto *DVI : DVIs)
    if (DVI->isAddressOfVariable() || DVI->getExpression()->startsWithDeref())
      DVI->eraseFromParent();

  return eraseInstFromFunction(MI);
}
return nullptr;
2757}

2759/// Move the call to free before a NULL test.
2760///
2761/// Check if this free is accessed after its argument has been test
2762/// against NULL (property 0).
2763/// If yes, it is legal to move this call in its predecessor block.
2764///
2765/// The move is performed only if the block containing the call to free
2766/// will be removed, i.e.:
2767/// 1. it has only one predecessor P, and P has two successors
2768/// 2. it contains the call, noops, and an unconditional branch
2769/// 3. its successor is the same as its predecessor's successor
2770///
2771/// The profitability is out-of concern here and this function should
2772/// be called only if the caller knows this transformation would be
2773/// profitable (e.g., for code size).
2774static Instruction *tryToMoveFreeBeforeNullTest(CallInst &FI,
                                              const DataLayout &DL) {
Value *Op = FI.getArgOperand(0);
BasicBlock *FreeInstrBB = FI.getParent();
BasicBlock *PredBB = FreeInstrBB->getSinglePredecessor();

// Validate part of constraint #1: Only one predecessor
// FIXME: We can extend the number of predecessor, but in that case, we
//        would duplicate the call to free in each predecessor and it may
//        not be profitable even for code size.
if (!PredBB)
  return nullptr;

// Validate constraint #2: Does this block contains only the call to
//                         free, noops, and an unconditional branch?
BasicBlock *SuccBB;
Instruction *FreeInstrBBTerminator = FreeInstrBB->getTerminator();
if (!match(FreeInstrBBTerminator, m_UnconditionalBr(SuccBB)))
  return nullptr;

// If there are only 2 instructions in the block, at this point,
// this is the call to free and unconditional.
// If there are more than 2 instructions, check that they are noops
// i.e., they won't hurt the performance of the generated code.
if (FreeInstrBB->size() != 2) {
  for (const Instruction &Inst : FreeInstrBB->instructionsWithoutDebug()) {
    if (&Inst == &FI || &Inst == FreeInstrBBTerminator)
      continue;
    auto *Cast = dyn_cast<CastInst>(&Inst);
    if (!Cast || !Cast->isNoopCast(DL))
      return nullptr;
  }
}
// Validate the rest of constraint #1 by matching on the pred branch.
Instruction *TI = PredBB->getTerminator();
BasicBlock *TrueBB, *FalseBB;
ICmpInst::Predicate Pred;
if (!match(TI, m_Br(m_ICmp(Pred,
                           m_CombineOr(m_Specific(Op),
                                       m_Specific(Op->stripPointerCasts())),
                           m_Zero()),
                    TrueBB, FalseBB)))
  return nullptr;
if (Pred != ICmpInst::ICMP_EQ && Pred != ICmpInst::ICMP_NE)
  return nullptr;

// Validate constraint #3: Ensure the null case just falls through.
if (SuccBB != (Pred == ICmpInst::ICMP_EQ ? TrueBB : FalseBB))
  return nullptr;
assert(FreeInstrBB == (Pred == ICmpInst::ICMP_EQ ? FalseBB : TrueBB) &&(static_cast <bool> (FreeInstrBB == (Pred == ICmpInst::
ICMP_EQ ? FalseBB : TrueBB) && "Broken CFG: missing edge from predecessor to successor"
) ? void (0) : __assert_fail ("FreeInstrBB == (Pred == ICmpInst::ICMP_EQ ? FalseBB : TrueBB) && \"Broken CFG: missing edge from predecessor to successor\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2824, __extension__ __PRETTY_FUNCTION__))
       "Broken CFG: missing edge from predecessor to successor")(static_cast <bool> (FreeInstrBB == (Pred == ICmpInst::
ICMP_EQ ? FalseBB : TrueBB) && "Broken CFG: missing edge from predecessor to successor"
) ? void (0) : __assert_fail ("FreeInstrBB == (Pred == ICmpInst::ICMP_EQ ? FalseBB : TrueBB) && \"Broken CFG: missing edge from predecessor to successor\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2824, __extension__ __PRETTY_FUNCTION__));

// At this point, we know that everything in FreeInstrBB can be moved
// before TI.
for (BasicBlock::iterator It = FreeInstrBB->begin(), End = FreeInstrBB->end();
     It != End;) {
  Instruction &Instr = *It++;
  if (&Instr == FreeInstrBBTerminator)
    break;
  Instr.moveBefore(TI);
}
assert(FreeInstrBB->size() == 1 &&(static_cast <bool> (FreeInstrBB->size() == 1 &&
 "Only the branch instruction should remain") ? void (0) : __assert_fail
 ("FreeInstrBB->size() == 1 && \"Only the branch instruction should remain\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2836, __extension__ __PRETTY_FUNCTION__))
       "Only the branch instruction should remain")(static_cast <bool> (FreeInstrBB->size() == 1 &&
 "Only the branch instruction should remain") ? void (0) : __assert_fail
 ("FreeInstrBB->size() == 1 && \"Only the branch instruction should remain\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2836, __extension__ __PRETTY_FUNCTION__));
return &FI;
2838}

2840Instruction *InstCombinerImpl::visitFree(CallInst &FI) {
Value *Op = FI.getArgOperand(0);

// free undef -> unreachable.
if (isa<UndefValue>(Op)) {
  // Leave a marker since we can't modify the CFG here.
  CreateNonTerminatorUnreachable(&FI);
  return eraseInstFromFunction(FI);
}

// If we have 'free null' delete the instruction.  This can happen in stl code
// when lots of inlining happens.
if (isa<ConstantPointerNull>(Op))
  return eraseInstFromFunction(FI);

// If we optimize for code size, try to move the call to free before the null
// test so that simplify cfg can remove the empty block and dead code
// elimination the branch. I.e., helps to turn something like:
// if (foo) free(foo);
// into
// free(foo);
//
// Note that we can only do this for 'free' and not for any flavor of
// 'operator delete'; there is no 'operator delete' symbol for which we are
// permitted to invent a call, even if we're passing in a null pointer.
if (MinimizeSize) {
  LibFunc Func;
  if (TLI.getLibFunc(FI, Func) && TLI.has(Func) && Func == LibFunc_free)
    if (Instruction *I = tryToMoveFreeBeforeNullTest(FI, DL))
      return I;
}

return nullptr;
2873}

2875static bool isMustTailCall(Value *V) {
if (auto *CI = dyn_cast<CallInst>(V))
  return CI->isMustTailCall();
return false;
2879}

2881Instruction *InstCombinerImpl::visitReturnInst(ReturnInst &RI) {
if (RI.getNumOperands() == 0) // ret void
  return nullptr;

Value *ResultOp = RI.getOperand(0);
Type *VTy = ResultOp->getType();
if (!VTy->isIntegerTy() || isa<Constant>(ResultOp))
  return nullptr;

// Don't replace result of musttail calls.
if (isMustTailCall(ResultOp))
  return nullptr;

// There might be assume intrinsics dominating this return that completely
// determine the value. If so, constant fold it.
KnownBits Known = computeKnownBits(ResultOp, 0, &RI);
if (Known.isConstant())
  return replaceOperand(RI, 0,
      Constant::getIntegerValue(VTy, Known.getConstant()));

return nullptr;
2902}

2904// WARNING: keep in sync with SimplifyCFGOpt::simplifyUnreachable()!
2905Instruction *InstCombinerImpl::visitUnreachableInst(UnreachableInst &I) {
// Try to remove the previous instruction if it must lead to unreachable.
// This includes instructions like stores and "llvm.assume" that may not get
// removed by simple dead code elimination.
while (Instruction *Prev = I.getPrevNonDebugInstruction()) {
  // While we theoretically can erase EH, that would result in a block that
  // used to start with an EH no longer starting with EH, which is invalid.
  // To make it valid, we'd need to fixup predecessors to no longer refer to
  // this block, but that changes CFG, which is not allowed in InstCombine.
  if (Prev->isEHPad())
    return nullptr; // Can not drop any more instructions. We're done here.

  if (!isGuaranteedToTransferExecutionToSuccessor(Prev))
    return nullptr; // Can not drop any more instructions. We're done here.
  // Otherwise, this instruction can be freely erased,
  // even if it is not side-effect free.

  // A value may still have uses before we process it here (for example, in
  // another unreachable block), so convert those to poison.
  replaceInstUsesWith(*Prev, PoisonValue::get(Prev->getType()));
  eraseInstFromFunction(*Prev);
}
assert(I.getParent()->sizeWithoutDebug() == 1 && "The block is now empty.")(static_cast <bool> (I.getParent()->sizeWithoutDebug
() == 1 && "The block is now empty.") ? void (0) : __assert_fail
 ("I.getParent()->sizeWithoutDebug() == 1 && \"The block is now empty.\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2927, __extension__ __PRETTY_FUNCTION__));
// FIXME: recurse into unconditional predecessors?
return nullptr;
2930}

2932Instruction *InstCombinerImpl::visitUnconditionalBranchInst(BranchInst &BI) {
assert(BI.isUnconditional() && "Only for unconditional branches.")(static_cast <bool> (BI.isUnconditional() && "Only for unconditional branches."
) ? void (0) : __assert_fail ("BI.isUnconditional() && \"Only for unconditional branches.\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 2933, __extension__ __PRETTY_FUNCTION__));

// If this store is the second-to-last instruction in the basic block
// (excluding debug info and bitcasts of pointers) and if the block ends with
// an unconditional branch, try to move the store to the successor block.

auto GetLastSinkableStore = [](BasicBlock::iterator BBI) {
  auto IsNoopInstrForStoreMerging = [](BasicBlock::iterator BBI) {
    return isa<DbgInfoIntrinsic>(BBI) ||
           (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy());
  };

  BasicBlock::iterator FirstInstr = BBI->getParent()->begin();
  do {
    if (BBI != FirstInstr)
      --BBI;
  } while (BBI != FirstInstr && IsNoopInstrForStoreMerging(BBI));

  return dyn_cast<StoreInst>(BBI);
};

if (StoreInst *SI = GetLastSinkableStore(BasicBlock::iterator(BI)))
  if (mergeStoreIntoSuccessor(*SI))
    return &BI;

return nullptr;
2959}

2961Instruction *InstCombinerImpl::visitBranchInst(BranchInst &BI) {
if (BI.isUnconditional())
  return visitUnconditionalBranchInst(BI);

// Change br (not X), label True, label False to: br X, label False, True
Value *X = nullptr;
if (match(&BI, m_Br(m_Not(m_Value(X)), m_BasicBlock(), m_BasicBlock())) &&
    !isa<Constant>(X)) {
  // Swap Destinations and condition...
  BI.swapSuccessors();
  return replaceOperand(BI, 0, X);
}

// If the condition is irrelevant, remove the use so that other
// transforms on the condition become more effective.
if (!isa<ConstantInt>(BI.getCondition()) &&
    BI.getSuccessor(0) == BI.getSuccessor(1))
  return replaceOperand(
      BI, 0, ConstantInt::getFalse(BI.getCondition()->getType()));

// Canonicalize, for example, fcmp_one -> fcmp_oeq.
CmpInst::Predicate Pred;
if (match(&BI, m_Br(m_OneUse(m_FCmp(Pred, m_Value(), m_Value())),
                    m_BasicBlock(), m_BasicBlock())) &&
    !isCanonicalPredicate(Pred)) {
  // Swap destinations and condition.
  CmpInst *Cond = cast<CmpInst>(BI.getCondition());
  Cond->setPredicate(CmpInst::getInversePredicate(Pred));
  BI.swapSuccessors();
  Worklist.push(Cond);
  return &BI;
}

return nullptr;
2995}

2997Instruction *InstCombinerImpl::visitSwitchInst(SwitchInst &SI) {
Value *Cond = SI.getCondition();
Value *Op0;
ConstantInt *AddRHS;
if (match(Cond, m_Add(m_Value(Op0), m_ConstantInt(AddRHS)))) {
  // Change 'switch (X+4) case 1:' into 'switch (X) case -3'.
  for (auto Case : SI.cases()) {
    Constant *NewCase = ConstantExpr::getSub(Case.getCaseValue(), AddRHS);
    assert(isa<ConstantInt>(NewCase) &&(static_cast <bool> (isa<ConstantInt>(NewCase) &&
 "Result of expression should be constant") ? void (0) : __assert_fail
 ("isa<ConstantInt>(NewCase) && \"Result of expression should be constant\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3006, __extension__ __PRETTY_FUNCTION__))
           "Result of expression should be constant")(static_cast <bool> (isa<ConstantInt>(NewCase) &&
 "Result of expression should be constant") ? void (0) : __assert_fail
 ("isa<ConstantInt>(NewCase) && \"Result of expression should be constant\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3006, __extension__ __PRETTY_FUNCTION__));
    Case.setValue(cast<ConstantInt>(NewCase));
  }
  return replaceOperand(SI, 0, Op0);
}

KnownBits Known = computeKnownBits(Cond, 0, &SI);
unsigned LeadingKnownZeros = Known.countMinLeadingZeros();
unsigned LeadingKnownOnes = Known.countMinLeadingOnes();

// Compute the number of leading bits we can ignore.
// TODO: A better way to determine this would use ComputeNumSignBits().
for (auto &C : SI.cases()) {
  LeadingKnownZeros = std::min(
      LeadingKnownZeros, C.getCaseValue()->getValue().countLeadingZeros());
  LeadingKnownOnes = std::min(
      LeadingKnownOnes, C.getCaseValue()->getValue().countLeadingOnes());
}

unsigned NewWidth = Known.getBitWidth() - std::max(LeadingKnownZeros, LeadingKnownOnes);

// Shrink the condition operand if the new type is smaller than the old type.
// But do not shrink to a non-standard type, because backend can't generate
// good code for that yet.
// TODO: We can make it aggressive again after fixing PR39569.
if (NewWidth > 0 && NewWidth < Known.getBitWidth() &&
    shouldChangeType(Known.getBitWidth(), NewWidth)) {
  IntegerType *Ty = IntegerType::get(SI.getContext(), NewWidth);
  Builder.SetInsertPoint(&SI);
  Value *NewCond = Builder.CreateTrunc(Cond, Ty, "trunc");

  for (auto Case : SI.cases()) {
    APInt TruncatedCase = Case.getCaseValue()->getValue().trunc(NewWidth);
    Case.setValue(ConstantInt::get(SI.getContext(), TruncatedCase));
  }
  return replaceOperand(SI, 0, NewCond);
}

return nullptr;
3045}

3047Instruction *InstCombinerImpl::visitExtractValueInst(ExtractValueInst &EV) {
Value *Agg = EV.getAggregateOperand();

if (!EV.hasIndices())
  return replaceInstUsesWith(EV, Agg);

if (Value *V = SimplifyExtractValueInst(Agg, EV.getIndices(),
                                        SQ.getWithInstruction(&EV)))
  return replaceInstUsesWith(EV, V);

if (InsertValueInst *IV = dyn_cast<InsertValueInst>(Agg)) {
  // We're extracting from an insertvalue instruction, compare the indices
  const unsigned *exti, *exte, *insi, *inse;
  for (exti = EV.idx_begin(), insi = IV->idx_begin(),
       exte = EV.idx_end(), inse = IV->idx_end();
       exti != exte && insi != inse;
       ++exti, ++insi) {
    if (*insi != *exti)
      // The insert and extract both reference distinctly different elements.
      // This means the extract is not influenced by the insert, and we can
      // replace the aggregate operand of the extract with the aggregate
      // operand of the insert. i.e., replace
      // %I = insertvalue { i32, { i32 } } %A, { i32 } { i32 42 }, 1
      // %E = extractvalue { i32, { i32 } } %I, 0
      // with
      // %E = extractvalue { i32, { i32 } } %A, 0
      return ExtractValueInst::Create(IV->getAggregateOperand(),
                                      EV.getIndices());
  }
  if (exti == exte && insi == inse)
    // Both iterators are at the end: Index lists are identical. Replace
    // %B = insertvalue { i32, { i32 } } %A, i32 42, 1, 0
    // %C = extractvalue { i32, { i32 } } %B, 1, 0
    // with "i32 42"
    return replaceInstUsesWith(EV, IV->getInsertedValueOperand());
  if (exti == exte) {
    // The extract list is a prefix of the insert list. i.e. replace
    // %I = insertvalue { i32, { i32 } } %A, i32 42, 1, 0
    // %E = extractvalue { i32, { i32 } } %I, 1
    // with
    // %X = extractvalue { i32, { i32 } } %A, 1
    // %E = insertvalue { i32 } %X, i32 42, 0
    // by switching the order of the insert and extract (though the
    // insertvalue should be left in, since it may have other uses).
    Value *NewEV = Builder.CreateExtractValue(IV->getAggregateOperand(),
                                              EV.getIndices());
    return InsertValueInst::Create(NewEV, IV->getInsertedValueOperand(),
                                   makeArrayRef(insi, inse));
  }
  if (insi == inse)
    // The insert list is a prefix of the extract list
    // We can simply remove the common indices from the extract and make it
    // operate on the inserted value instead of the insertvalue result.
    // i.e., replace
    // %I = insertvalue { i32, { i32 } } %A, { i32 } { i32 42 }, 1
    // %E = extractvalue { i32, { i32 } } %I, 1, 0
    // with
    // %E extractvalue { i32 } { i32 42 }, 0
    return ExtractValueInst::Create(IV->getInsertedValueOperand(),
                                    makeArrayRef(exti, exte));
}
if (WithOverflowInst *WO = dyn_cast<WithOverflowInst>(Agg)) {
  // We're extracting from an overflow intrinsic, see if we're the only user,
  // which allows us to simplify multiple result intrinsics to simpler
  // things that just get one value.
  if (WO->hasOneUse()) {
    // Check if we're grabbing only the result of a 'with overflow' intrinsic
    // and replace it with a traditional binary instruction.
    if (*EV.idx_begin() == 0) {
      Instruction::BinaryOps BinOp = WO->getBinaryOp();
      Value *LHS = WO->getLHS(), *RHS = WO->getRHS();
      // Replace the old instruction's uses with poison.
      replaceInstUsesWith(*WO, PoisonValue::get(WO->getType()));
      eraseInstFromFunction(*WO);
      return BinaryOperator::Create(BinOp, LHS, RHS);
    }

    assert(*EV.idx_begin() == 1 &&(static_cast <bool> (*EV.idx_begin() == 1 && "unexpected extract index for overflow inst"
) ? void (0) : __assert_fail ("*EV.idx_begin() == 1 && \"unexpected extract index for overflow inst\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3125, __extension__ __PRETTY_FUNCTION__))
           "unexpected extract index for overflow inst")(static_cast <bool> (*EV.idx_begin() == 1 && "unexpected extract index for overflow inst"
) ? void (0) : __assert_fail ("*EV.idx_begin() == 1 && \"unexpected extract index for overflow inst\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3125, __extension__ __PRETTY_FUNCTION__));

    // If only the overflow result is used, and the right hand side is a
    // constant (or constant splat), we can remove the intrinsic by directly
    // checking for overflow.
    const APInt *C;
    if (match(WO->getRHS(), m_APInt(C))) {
      // Compute the no-wrap range [X,Y) for LHS given RHS=C, then
      // check for the inverted range using range offset trick (i.e.
      // use a subtract to shift the range to bottom of either the
      // signed or unsigned domain and then use a single compare to
      // check range membership).
      ConstantRange NWR =
        ConstantRange::makeExactNoWrapRegion(WO->getBinaryOp(), *C,
                                             WO->getNoWrapKind());
      APInt Min = WO->isSigned() ? NWR.getSignedMin() : NWR.getUnsignedMin();
      NWR = NWR.subtract(Min);

      CmpInst::Predicate Pred;
      APInt NewRHSC;
      if (NWR.getEquivalentICmp(Pred, NewRHSC)) {
        auto *OpTy = WO->getRHS()->getType();
        auto *NewLHS = Builder.CreateSub(WO->getLHS(),
                                         ConstantInt::get(OpTy, Min));
        return new ICmpInst(ICmpInst::getInversePredicate(Pred), NewLHS,
                            ConstantInt::get(OpTy, NewRHSC));
      }
    }
  }
}
if (LoadInst *L = dyn_cast<LoadInst>(Agg))
  // If the (non-volatile) load only has one use, we can rewrite this to a
  // load from a GEP. This reduces the size of the load. If a load is used
  // only by extractvalue instructions then this either must have been
  // optimized before, or it is a struct with padding, in which case we
  // don't want to do the transformation as it loses padding knowledge.
  if (L->isSimple() && L->hasOneUse()) {
    // extractvalue has integer indices, getelementptr has Value*s. Convert.
    SmallVector<Value*, 4> Indices;
    // Prefix an i32 0 since we need the first element.
    Indices.push_back(Builder.getInt32(0));
    for (unsigned Idx : EV.indices())
      Indices.push_back(Builder.getInt32(Idx));

    // We need to insert these at the location of the old load, not at that of
    // the extractvalue.
    Builder.SetInsertPoint(L);
    Value *GEP = Builder.CreateInBoundsGEP(L->getType(),
                                           L->getPointerOperand(), Indices);
    Instruction *NL = Builder.CreateLoad(EV.getType(), GEP);
    // Whatever aliasing information we had for the orignal load must also
    // hold for the smaller load, so propagate the annotations.
    AAMDNodes Nodes;
    L->getAAMetadata(Nodes);
    NL->setAAMetadata(Nodes);
    // Returning the load directly will cause the main loop to insert it in
    // the wrong spot, so use replaceInstUsesWith().
    return replaceInstUsesWith(EV, NL);
  }
// We could simplify extracts from other values. Note that nested extracts may
// already be simplified implicitly by the above: extract (extract (insert) )
// will be translated into extract ( insert ( extract ) ) first and then just
// the value inserted, if appropriate. Similarly for extracts from single-use
// loads: extract (extract (load)) will be translated to extract (load (gep))
// and if again single-use then via load (gep (gep)) to load (gep).
// However, double extracts from e.g. function arguments or return values
// aren't handled yet.
return nullptr;
3193}

3195/// Return 'true' if the given typeinfo will match anything.
3196static bool isCatchAll(EHPersonality Personality, Constant *TypeInfo) {
switch (Personality) {
case EHPersonality::GNU_C:
case EHPersonality::GNU_C_SjLj:
case EHPersonality::Rust:
  // The GCC C EH and Rust personality only exists to support cleanups, so
  // it's not clear what the semantics of catch clauses are.
  return false;
case EHPersonality::Unknown:
  return false;
case EHPersonality::GNU_Ada:
  // While __gnat_all_others_value will match any Ada exception, it doesn't
  // match foreign exceptions (or didn't, before gcc-4.7).
  return false;
case EHPersonality::GNU_CXX:
case EHPersonality::GNU_CXX_SjLj:
case EHPersonality::GNU_ObjC:
case EHPersonality::MSVC_X86SEH:
case EHPersonality::MSVC_TableSEH:
case EHPersonality::MSVC_CXX:
case EHPersonality::CoreCLR:
case EHPersonality::Wasm_CXX:
case EHPersonality::XL_CXX:
  return TypeInfo->isNullValue();
}
llvm_unreachable("invalid enum")::llvm::llvm_unreachable_internal("invalid enum", "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3221);
3222}

3224static bool shorter_filter(const Value *LHS, const Value *RHS) {
return
  cast<ArrayType>(LHS->getType())->getNumElements()
<
  cast<ArrayType>(RHS->getType())->getNumElements();
3229}

3231Instruction *InstCombinerImpl::visitLandingPadInst(LandingPadInst &LI) {
// The logic here should be correct for any real-world personality function.
// However if that turns out not to be true, the offending logic can always
// be conditioned on the personality function, like the catch-all logic is.
EHPersonality Personality =
    classifyEHPersonality(LI.getParent()->getParent()->getPersonalityFn());

// Simplify the list of clauses, eg by removing repeated catch clauses
// (these are often created by inlining).
bool MakeNewInstruction = false; // If true, recreate using the following:
SmallVector<Constant *, 16> NewClauses; // - Clauses for the new instruction;
bool CleanupFlag = LI.isCleanup();   // - The new instruction is a cleanup.

SmallPtrSet<Value *, 16> AlreadyCaught; // Typeinfos known caught already.
for (unsigned i = 0, e = LI.getNumClauses(); i != e; ++i) {
  bool isLastClause = i + 1 == e;
  if (LI.isCatch(i)) {
    // A catch clause.
    Constant *CatchClause = LI.getClause(i);
    Constant *TypeInfo = CatchClause->stripPointerCasts();

    // If we already saw this clause, there is no point in having a second
    // copy of it.
    if (AlreadyCaught.insert(TypeInfo).second) {
      // This catch clause was not already seen.
      NewClauses.push_back(CatchClause);
    } else {
      // Repeated catch clause - drop the redundant copy.
      MakeNewInstruction = true;
    }

    // If this is a catch-all then there is no point in keeping any following
    // clauses or marking the landingpad as having a cleanup.
    if (isCatchAll(Personality, TypeInfo)) {
      if (!isLastClause)
        MakeNewInstruction = true;
      CleanupFlag = false;
      break;
    }
  } else {
    // A filter clause.  If any of the filter elements were already caught
    // then they can be dropped from the filter.  It is tempting to try to
    // exploit the filter further by saying that any typeinfo that does not
    // occur in the filter can't be caught later (and thus can be dropped).
    // However this would be wrong, since typeinfos can match without being
    // equal (for example if one represents a C++ class, and the other some
    // class derived from it).
    assert(LI.isFilter(i) && "Unsupported landingpad clause!")(static_cast <bool> (LI.isFilter(i) && "Unsupported landingpad clause!"
) ? void (0) : __assert_fail ("LI.isFilter(i) && \"Unsupported landingpad clause!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3278, __extension__ __PRETTY_FUNCTION__));
    Constant *FilterClause = LI.getClause(i);
    ArrayType *FilterType = cast<ArrayType>(FilterClause->getType());
    unsigned NumTypeInfos = FilterType->getNumElements();

    // An empty filter catches everything, so there is no point in keeping any
    // following clauses or marking the landingpad as having a cleanup.  By
    // dealing with this case here the following code is made a bit simpler.
    if (!NumTypeInfos) {
      NewClauses.push_back(FilterClause);
      if (!isLastClause)
        MakeNewInstruction = true;
      CleanupFlag = false;
      break;
    }

    bool MakeNewFilter = false; // If true, make a new filter.
    SmallVector<Constant *, 16> NewFilterElts; // New elements.
    if (isa<ConstantAggregateZero>(FilterClause)) {
      // Not an empty filter - it contains at least one null typeinfo.
      assert(NumTypeInfos > 0 && "Should have handled empty filter already!")(static_cast <bool> (NumTypeInfos > 0 && "Should have handled empty filter already!"
) ? void (0) : __assert_fail ("NumTypeInfos > 0 && \"Should have handled empty filter already!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3298, __extension__ __PRETTY_FUNCTION__));
      Constant *TypeInfo =
        Constant::getNullValue(FilterType->getElementType());
      // If this typeinfo is a catch-all then the filter can never match.
      if (isCatchAll(Personality, TypeInfo)) {
        // Throw the filter away.
        MakeNewInstruction = true;
        continue;
      }

      // There is no point in having multiple copies of this typeinfo, so
      // discard all but the first copy if there is more than one.
      NewFilterElts.push_back(TypeInfo);
      if (NumTypeInfos > 1)
        MakeNewFilter = true;
    } else {
      ConstantArray *Filter = cast<ConstantArray>(FilterClause);
      SmallPtrSet<Value *, 16> SeenInFilter; // For uniquing the elements.
      NewFilterElts.reserve(NumTypeInfos);

      // Remove any filter elements that were already caught or that already
      // occurred in the filter.  While there, see if any of the elements are
      // catch-alls.  If so, the filter can be discarded.
      bool SawCatchAll = false;
      for (unsigned j = 0; j != NumTypeInfos; ++j) {
        Constant *Elt = Filter->getOperand(j);
        Constant *TypeInfo = Elt->stripPointerCasts();
        if (isCatchAll(Personality, TypeInfo)) {
          // This element is a catch-all.  Bail out, noting this fact.
          SawCatchAll = true;
          break;
        }

        // Even if we've seen a type in a catch clause, we don't want to
        // remove it from the filter.  An unexpected type handler may be
        // set up for a call site which throws an exception of the same
        // type caught.  In order for the exception thrown by the unexpected
        // handler to propagate correctly, the filter must be correctly
        // described for the call site.
        //
        // Example:
        //
        // void unexpected() { throw 1;}
        // void foo() throw (int) {
        //   std::set_unexpected(unexpected);
        //   try {
        //     throw 2.0;
        //   } catch (int i) {}
        // }

        // There is no point in having multiple copies of the same typeinfo in
        // a filter, so only add it if we didn't already.
        if (SeenInFilter.insert(TypeInfo).second)
          NewFilterElts.push_back(cast<Constant>(Elt));
      }
      // A filter containing a catch-all cannot match anything by definition.
      if (SawCatchAll) {
        // Throw the filter away.
        MakeNewInstruction = true;
        continue;
      }

      // If we dropped something from the filter, make a new one.
      if (NewFilterElts.size() < NumTypeInfos)
        MakeNewFilter = true;
    }
    if (MakeNewFilter) {
      FilterType = ArrayType::get(FilterType->getElementType(),
                                  NewFilterElts.size());
      FilterClause = ConstantArray::get(FilterType, NewFilterElts);
      MakeNewInstruction = true;
    }

    NewClauses.push_back(FilterClause);

    // If the new filter is empty then it will catch everything so there is
    // no point in keeping any following clauses or marking the landingpad
    // as having a cleanup.  The case of the original filter being empty was
    // already handled above.
    if (MakeNewFilter && !NewFilterElts.size()) {
      assert(MakeNewInstruction && "New filter but not a new instruction!")(static_cast <bool> (MakeNewInstruction && "New filter but not a new instruction!"
) ? void (0) : __assert_fail ("MakeNewInstruction && \"New filter but not a new instruction!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3378, __extension__ __PRETTY_FUNCTION__));
      CleanupFlag = false;
      break;
    }
  }
}

// If several filters occur in a row then reorder them so that the shortest
// filters come first (those with the smallest number of elements).  This is
// advantageous because shorter filters are more likely to match, speeding up
// unwinding, but mostly because it increases the effectiveness of the other
// filter optimizations below.
for (unsigned i = 0, e = NewClauses.size(); i + 1 < e; ) {
  unsigned j;
  // Find the maximal 'j' s.t. the range [i, j) consists entirely of filters.
  for (j = i; j != e; ++j)
    if (!isa<ArrayType>(NewClauses[j]->getType()))
      break;

  // Check whether the filters are already sorted by length.  We need to know
  // if sorting them is actually going to do anything so that we only make a
  // new landingpad instruction if it does.
  for (unsigned k = i; k + 1 < j; ++k)
    if (shorter_filter(NewClauses[k+1], NewClauses[k])) {
      // Not sorted, so sort the filters now.  Doing an unstable sort would be
      // correct too but reordering filters pointlessly might confuse users.
      std::stable_sort(NewClauses.begin() + i, NewClauses.begin() + j,
                       shorter_filter);
      MakeNewInstruction = true;
      break;
    }

  // Look for the next batch of filters.
  i = j + 1;
}

// If typeinfos matched if and only if equal, then the elements of a filter L
// that occurs later than a filter F could be replaced by the intersection of
// the elements of F and L.  In reality two typeinfos can match without being
// equal (for example if one represents a C++ class, and the other some class
// derived from it) so it would be wrong to perform this transform in general.
// However the transform is correct and useful if F is a subset of L.  In that
// case L can be replaced by F, and thus removed altogether since repeating a
// filter is pointless.  So here we look at all pairs of filters F and L where
// L follows F in the list of clauses, and remove L if every element of F is
// an element of L.  This can occur when inlining C++ functions with exception
// specifications.
for (unsigned i = 0; i + 1 < NewClauses.size(); ++i) {
  // Examine each filter in turn.
  Value *Filter = NewClauses[i];
  ArrayType *FTy = dyn_cast<ArrayType>(Filter->getType());
  if (!FTy)
    // Not a filter - skip it.
    continue;
  unsigned FElts = FTy->getNumElements();
  // Examine each filter following this one.  Doing this backwards means that
  // we don't have to worry about filters disappearing under us when removed.
  for (unsigned j = NewClauses.size() - 1; j != i; --j) {
    Value *LFilter = NewClauses[j];
    ArrayType *LTy = dyn_cast<ArrayType>(LFilter->getType());
    if (!LTy)
      // Not a filter - skip it.
      continue;
    // If Filter is a subset of LFilter, i.e. every element of Filter is also
    // an element of LFilter, then discard LFilter.
    SmallVectorImpl<Constant *>::iterator J = NewClauses.begin() + j;
    // If Filter is empty then it is a subset of LFilter.
    if (!FElts) {
      // Discard LFilter.
      NewClauses.erase(J);
      MakeNewInstruction = true;
      // Move on to the next filter.
      continue;
    }
    unsigned LElts = LTy->getNumElements();
    // If Filter is longer than LFilter then it cannot be a subset of it.
    if (FElts > LElts)
      // Move on to the next filter.
      continue;
    // At this point we know that LFilter has at least one element.
    if (isa<ConstantAggregateZero>(LFilter)) { // LFilter only contains zeros.
      // Filter is a subset of LFilter iff Filter contains only zeros (as we
      // already know that Filter is not longer than LFilter).
      if (isa<ConstantAggregateZero>(Filter)) {
        assert(FElts <= LElts && "Should have handled this case earlier!")(static_cast <bool> (FElts <= LElts && "Should have handled this case earlier!"
) ? void (0) : __assert_fail ("FElts <= LElts && \"Should have handled this case earlier!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3462, __extension__ __PRETTY_FUNCTION__));
        // Discard LFilter.
        NewClauses.erase(J);
        MakeNewInstruction = true;
      }
      // Move on to the next filter.
      continue;
    }
    ConstantArray *LArray = cast<ConstantArray>(LFilter);
    if (isa<ConstantAggregateZero>(Filter)) { // Filter only contains zeros.
      // Since Filter is non-empty and contains only zeros, it is a subset of
      // LFilter iff LFilter contains a zero.
      assert(FElts > 0 && "Should have eliminated the empty filter earlier!")(static_cast <bool> (FElts > 0 && "Should have eliminated the empty filter earlier!"
) ? void (0) : __assert_fail ("FElts > 0 && \"Should have eliminated the empty filter earlier!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3474, __extension__ __PRETTY_FUNCTION__));
      for (unsigned l = 0; l != LElts; ++l)
        if (LArray->getOperand(l)->isNullValue()) {
          // LFilter contains a zero - discard it.
          NewClauses.erase(J);
          MakeNewInstruction = true;
          break;
        }
      // Move on to the next filter.
      continue;
    }
    // At this point we know that both filters are ConstantArrays.  Loop over
    // operands to see whether every element of Filter is also an element of
    // LFilter.  Since filters tend to be short this is probably faster than
    // using a method that scales nicely.
    ConstantArray *FArray = cast<ConstantArray>(Filter);
    bool AllFound = true;
    for (unsigned f = 0; f != FElts; ++f) {
      Value *FTypeInfo = FArray->getOperand(f)->stripPointerCasts();
      AllFound = false;
      for (unsigned l = 0; l != LElts; ++l) {
        Value *LTypeInfo = LArray->getOperand(l)->stripPointerCasts();
        if (LTypeInfo == FTypeInfo) {
          AllFound = true;
          break;
        }
      }
      if (!AllFound)
        break;
    }
    if (AllFound) {
      // Discard LFilter.
      NewClauses.erase(J);
      MakeNewInstruction = true;
    }
    // Move on to the next filter.
  }
}

// If we changed any of the clauses, replace the old landingpad instruction
// with a new one.
if (MakeNewInstruction) {
  LandingPadInst *NLI = LandingPadInst::Create(LI.getType(),
                                               NewClauses.size());
  for (unsigned i = 0, e = NewClauses.size(); i != e; ++i)
    NLI->addClause(NewClauses[i]);
  // A landing pad with no clauses must have the cleanup flag set.  It is
  // theoretically possible, though highly unlikely, that we eliminated all
  // clauses.  If so, force the cleanup flag to true.
  if (NewClauses.empty())
    CleanupFlag = true;
  NLI->setCleanup(CleanupFlag);
  return NLI;
}

// Even if none of the clauses changed, we may nonetheless have understood
// that the cleanup flag is pointless.  Clear it if so.
if (LI.isCleanup() != CleanupFlag) {
  assert(!CleanupFlag && "Adding a cleanup, not removing one?!")(static_cast <bool> (!CleanupFlag && "Adding a cleanup, not removing one?!"
) ? void (0) : __assert_fail ("!CleanupFlag && \"Adding a cleanup, not removing one?!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3532, __extension__ __PRETTY_FUNCTION__));
  LI.setCleanup(CleanupFlag);
  return &LI;
}

return nullptr;
3538}

3540Value *
3541InstCombinerImpl::pushFreezeToPreventPoisonFromPropagating(FreezeInst &OrigFI) {
// Try to push freeze through instructions that propagate but don't produce
// poison as far as possible.  If an operand of freeze follows three
// conditions 1) one-use, 2) does not produce poison, and 3) has all but one
// guaranteed-non-poison operands then push the freeze through to the one
// operand that is not guaranteed non-poison.  The actual transform is as
// follows.
//   Op1 = ...                        ; Op1 can be posion
//   Op0 = Inst(Op1, NonPoisonOps...) ; Op0 has only one use and only have
//                                    ; single guaranteed-non-poison operands
//   ... = Freeze(Op0)
// =>
//   Op1 = ...
//   Op1.fr = Freeze(Op1)
//   ... = Inst(Op1.fr, NonPoisonOps...)
auto *OrigOp = OrigFI.getOperand(0);
auto *OrigOpInst = dyn_cast<Instruction>(OrigOp);

// While we could change the other users of OrigOp to use freeze(OrigOp), that
// potentially reduces their optimization potential, so let's only do this iff
// the OrigOp is only used by the freeze.
if (!OrigOpInst || !OrigOpInst->hasOneUse() || isa<PHINode>(OrigOp) ||
6
←
Assuming 'OrigOpInst' is null→
    canCreateUndefOrPoison(dyn_cast<Operator>(OrigOp)))
  return nullptr;
7
←
Returning null pointer, which participates in a condition later→

// If operand is guaranteed not to be poison, there is no need to add freeze
// to the operand. So we first find the operand that is not guaranteed to be
// poison.
Use *MaybePoisonOperand = nullptr;
for (Use &U : OrigOpInst->operands()) {
  if (isGuaranteedNotToBeUndefOrPoison(U.get()))
    continue;
  if (!MaybePoisonOperand)
    MaybePoisonOperand = &U;
  else
    return nullptr;
}

// If all operands are guaranteed to be non-poison, we can drop freeze.
if (!MaybePoisonOperand)
  return OrigOp;

auto *FrozenMaybePoisonOperand = new FreezeInst(
    MaybePoisonOperand->get(), MaybePoisonOperand->get()->getName() + ".fr");

replaceUse(*MaybePoisonOperand, FrozenMaybePoisonOperand);
FrozenMaybePoisonOperand->insertBefore(OrigOpInst);
return OrigOp;
3589}

3591bool InstCombinerImpl::freezeDominatedUses(FreezeInst &FI) {
Value *Op = FI.getOperand(0);

if (isa<Constant>(Op))
  return false;

bool Changed = false;
Op->replaceUsesWithIf(&FI, [&](Use &U) -> bool {
  bool Dominates = DT.dominates(&FI, U);
  Changed |= Dominates;
  return Dominates;
});

return Changed;
3605}

3607Instruction *InstCombinerImpl::visitFreeze(FreezeInst &I) {
Value *Op0 = I.getOperand(0);

if (Value *V = SimplifyFreezeInst(Op0, SQ.getWithInstruction(&I)))
1
Assuming 'V' is null→
2
←
Taking false branch→
  return replaceInstUsesWith(I, V);

// freeze (phi const, x) --> phi const, (freeze x)
if (auto *PN = dyn_cast<PHINode>(Op0)) {
3
←
Assuming 'PN' is null→
4
←
Taking false branch→
  if (Instruction *NV = foldOpIntoPhi(I, PN))
    return NV;
}

if (Value *NI8.1
'NI' is null
1
'NI' is null
1
'NI' is null
 = pushFreezeToPreventPoisonFromPropagating(I))
5
←
Calling 'InstCombinerImpl::pushFreezeToPreventPoisonFromPropagating'→
8
←
Returning from 'InstCombinerImpl::pushFreezeToPreventPoisonFromPropagating'→
9
←
Taking false branch→
  return replaceInstUsesWith(I, NI);

if (match(Op0, m_Undef())) {
10
←
Assuming the condition is true→
11
←
Taking true branch→
  // If I is freeze(undef), see its uses and fold it to the best constant.
  // - or: pick -1
  // - select's condition: pick the value that leads to choosing a constant
  // - other ops: pick 0
  Constant *BestValue = nullptr;
12
←
'BestValue' initialized to a null pointer value→
  Constant *NullValue = Constant::getNullValue(I.getType());
  for (const auto *U : I.users()) {
    Constant *C = NullValue;

    if (match(U, m_Or(m_Value(), m_Value())))
      C = Constant::getAllOnesValue(I.getType());
    else if (const auto *SI = dyn_cast<SelectInst>(U)) {
      if (SI->getCondition() == &I) {
        APInt CondVal(1, isa<Constant>(SI->getFalseValue()) ? 0 : 1);
        C = Constant::getIntegerValue(I.getType(), CondVal);
      }
    }

    if (!BestValue)
      BestValue = C;
    else if (BestValue != C)
      BestValue = NullValue;
  }

  return replaceInstUsesWith(I, BestValue);
13
←
Passing null pointer value via 2nd parameter 'V'→
14
←
Calling 'InstCombinerImpl::replaceInstUsesWith'→
}

// Replace all dominated uses of Op to freeze(Op).
if (freezeDominatedUses(I))
  return &I;

return nullptr;
3655}

3657/// Try to move the specified instruction from its current block into the
3658/// beginning of DestBlock, which can only happen if it's safe to move the
3659/// instruction past all of the instructions between it and the end of its
3660/// block.
3661static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) {
assert(I->getSingleUndroppableUse() && "Invariants didn't hold!")(static_cast <bool> (I->getSingleUndroppableUse() &&
 "Invariants didn't hold!") ? void (0) : __assert_fail ("I->getSingleUndroppableUse() && \"Invariants didn't hold!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3662, __extension__ __PRETTY_FUNCTION__));
BasicBlock *SrcBlock = I->getParent();

// Cannot move control-flow-involving, volatile loads, vaarg, etc.
if (isa<PHINode>(I) || I->isEHPad() || I->mayHaveSideEffects() ||
    I->isTerminator())
  return false;

// Do not sink static or dynamic alloca instructions. Static allocas must
// remain in the entry block, and dynamic allocas must not be sunk in between
// a stacksave / stackrestore pair, which would incorrectly shorten its
// lifetime.
if (isa<AllocaInst>(I))
  return false;

// Do not sink into catchswitch blocks.
if (isa<CatchSwitchInst>(DestBlock->getTerminator()))
  return false;

// Do not sink convergent call instructions.
if (auto *CI = dyn_cast<CallInst>(I)) {
  if (CI->isConvergent())
    return false;
}
// We can only sink load instructions if there is nothing between the load and
// the end of block that could change the value.
if (I->mayReadFromMemory()) {
  // We don't want to do any sophisticated alias analysis, so we only check
  // the instructions after I in I's parent block if we try to sink to its
  // successor block.
  if (DestBlock->getUniquePredecessor() != I->getParent())
    return false;
  for (BasicBlock::iterator Scan = I->getIterator(),
                            E = I->getParent()->end();
       Scan != E; ++Scan)
    if (Scan->mayWriteToMemory())
      return false;
}

I->dropDroppableUses([DestBlock](const Use *U) {
  if (auto *I = dyn_cast<Instruction>(U->getUser()))
    return I->getParent() != DestBlock;
  return true;
});
/// FIXME: We could remove droppable uses that are not dominated by
/// the new position.

BasicBlock::iterator InsertPos = DestBlock->getFirstInsertionPt();
I->moveBefore(&*InsertPos);
++NumSunkInst;

// Also sink all related debug uses from the source basic block. Otherwise we
// get debug use before the def. Attempt to salvage debug uses first, to
// maximise the range variables have location for. If we cannot salvage, then
// mark the location undef: we know it was supposed to receive a new location
// here, but that computation has been sunk.
SmallVector<DbgVariableIntrinsic *, 2> DbgUsers;
findDbgUsers(DbgUsers, I);
// Process the sinking DbgUsers in reverse order, as we only want to clone the
// last appearing debug intrinsic for each given variable.
SmallVector<DbgVariableIntrinsic *, 2> DbgUsersToSink;
for (DbgVariableIntrinsic *DVI : DbgUsers)
  if (DVI->getParent() == SrcBlock)
    DbgUsersToSink.push_back(DVI);
llvm::sort(DbgUsersToSink,
           [](auto *A, auto *B) { return B->comesBefore(A); });

SmallVector<DbgVariableIntrinsic *, 2> DIIClones;
SmallSet<DebugVariable, 4> SunkVariables;
for (auto User : DbgUsersToSink) {
  // A dbg.declare instruction should not be cloned, since there can only be
  // one per variable fragment. It should be left in the original place
  // because the sunk instruction is not an alloca (otherwise we could not be
  // here).
  if (isa<DbgDeclareInst>(User))
    continue;

  DebugVariable DbgUserVariable =
      DebugVariable(User->getVariable(), User->getExpression(),
                    User->getDebugLoc()->getInlinedAt());

  if (!SunkVariables.insert(DbgUserVariable).second)
    continue;

  DIIClones.emplace_back(cast<DbgVariableIntrinsic>(User->clone()));
  if (isa<DbgDeclareInst>(User) && isa<CastInst>(I))
    DIIClones.back()->replaceVariableLocationOp(I, I->getOperand(0));
  LLVM_DEBUG(dbgs() << "CLONE: " << *DIIClones.back() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "CLONE: " << *DIIClones
.back() << '\n'; } } while (false);
}

// Perform salvaging without the clones, then sink the clones.
if (!DIIClones.empty()) {
  salvageDebugInfoForDbgValues(*I, DbgUsers);
  // The clones are in reverse order of original appearance, reverse again to
  // maintain the original order.
  for (auto &DIIClone : llvm::reverse(DIIClones)) {
    DIIClone->insertBefore(&*InsertPos);
    LLVM_DEBUG(dbgs() << "SINK: " << *DIIClone << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "SINK: " << *DIIClone
 << '\n'; } } while (false);
  }
}

return true;
3764}

3766bool InstCombinerImpl::run() {
while (!Worklist.isEmpty()) {
  // Walk deferred instructions in reverse order, and push them to the
  // worklist, which means they'll end up popped from the worklist in-order.
  while (Instruction *I = Worklist.popDeferred()) {
    // Check to see if we can DCE the instruction. We do this already here to
    // reduce the number of uses and thus allow other folds to trigger.
    // Note that eraseInstFromFunction() may push additional instructions on
    // the deferred worklist, so this will DCE whole instruction chains.
    if (isInstructionTriviallyDead(I, &TLI)) {
      eraseInstFromFunction(*I);
      ++NumDeadInst;
      continue;
    }

    Worklist.push(I);
  }

  Instruction *I = Worklist.removeOne();
  if (I == nullptr) continue;  // skip null values.

  // Check to see if we can DCE the instruction.
  if (isInstructionTriviallyDead(I, &TLI)) {
    eraseInstFromFunction(*I);
    ++NumDeadInst;
    continue;
  }

  if (!DebugCounter::shouldExecute(VisitCounter))
    continue;

  // Instruction isn't dead, see if we can constant propagate it.
  if (!I->use_empty() &&
      (I->getNumOperands() == 0 || isa<Constant>(I->getOperand(0)))) {
    if (Constant *C = ConstantFoldInstruction(I, DL, &TLI)) {
      LLVM_DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: " << *Ido { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold to: " <<
 *C << " from: " << *I << '\n'; } } while (
false)
                        << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold to: " <<
 *C << " from: " << *I << '\n'; } } while (
false);

      // Add operands to the worklist.
      replaceInstUsesWith(*I, C);
      ++NumConstProp;
      if (isInstructionTriviallyDead(I, &TLI))
        eraseInstFromFunction(*I);
      MadeIRChange = true;
      continue;
    }
  }

  // See if we can trivially sink this instruction to its user if we can
  // prove that the successor is not executed more frequently than our block.
  if (EnableCodeSinking)
    if (Use *SingleUse = I->getSingleUndroppableUse()) {
      BasicBlock *BB = I->getParent();
      Instruction *UserInst = cast<Instruction>(SingleUse->getUser());
      BasicBlock *UserParent;

      // Get the block the use occurs in.
      if (PHINode *PN = dyn_cast<PHINode>(UserInst))
        UserParent = PN->getIncomingBlock(*SingleUse);
      else
        UserParent = UserInst->getParent();

      // Try sinking to another block. If that block is unreachable, then do
      // not bother. SimplifyCFG should handle it.
      if (UserParent != BB && DT.isReachableFromEntry(UserParent)) {
        // See if the user is one of our successors that has only one
        // predecessor, so that we don't have to split the critical edge.
        bool ShouldSink = UserParent->getUniquePredecessor() == BB;
        // Another option where we can sink is a block that ends with a
        // terminator that does not pass control to other block (such as
        // return or unreachable). In this case:
        //   - I dominates the User (by SSA form);
        //   - the User will be executed at most once.
        // So sinking I down to User is always profitable or neutral.
        if (!ShouldSink) {
          auto *Term = UserParent->getTerminator();
          ShouldSink = isa<ReturnInst>(Term) || isa<UnreachableInst>(Term);
        }
        if (ShouldSink) {
          assert(DT.dominates(BB, UserParent) &&(static_cast <bool> (DT.dominates(BB, UserParent) &&
 "Dominance relation broken?") ? void (0) : __assert_fail ("DT.dominates(BB, UserParent) && \"Dominance relation broken?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3846, __extension__ __PRETTY_FUNCTION__))
                 "Dominance relation broken?")(static_cast <bool> (DT.dominates(BB, UserParent) &&
 "Dominance relation broken?") ? void (0) : __assert_fail ("DT.dominates(BB, UserParent) && \"Dominance relation broken?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3846, __extension__ __PRETTY_FUNCTION__));
          // Okay, the CFG is simple enough, try to sink this instruction.
          if (TryToSinkInstruction(I, UserParent)) {
            LLVM_DEBUG(dbgs() << "IC: Sink: " << *I << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Sink: " << *I <<
 '\n'; } } while (false);
            MadeIRChange = true;
            // We'll add uses of the sunk instruction below, but since sinking
            // can expose opportunities for it's *operands* add them to the
            // worklist
            for (Use &U : I->operands())
              if (Instruction *OpI = dyn_cast<Instruction>(U.get()))
                Worklist.push(OpI);
          }
        }
      }
    }

  // Now that we have an instruction, try combining it to simplify it.
  Builder.SetInsertPoint(I);
  Builder.CollectMetadataToCopy(
      I, {LLVMContext::MD_dbg, LLVMContext::MD_annotation});

3867#ifndef NDEBUG
  std::string OrigI;
3869#endif
  LLVM_DEBUG(raw_string_ostream SS(OrigI); I->print(SS); OrigI = SS.str();)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { raw_string_ostream SS(OrigI); I->print(
SS); OrigI = SS.str();; } } while (false);
  LLVM_DEBUG(dbgs() << "IC: Visiting: " << OrigI << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Visiting: " << OrigI
 << '\n'; } } while (false);

  if (Instruction *Result = visit(*I)) {
    ++NumCombined;
    // Should we replace the old instruction with a new one?
    if (Result != I) {
      LLVM_DEBUG(dbgs() << "IC: Old = " << *I << '\n'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Old = " << *I <<
 '\n' << "    New = " << *Result << '\n'; }
 } while (false)
                        << "    New = " << *Result << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Old = " << *I <<
 '\n' << "    New = " << *Result << '\n'; }
 } while (false);

      Result->copyMetadata(*I,
                           {LLVMContext::MD_dbg, LLVMContext::MD_annotation});
      // Everything uses the new instruction now.
      I->replaceAllUsesWith(Result);

      // Move the name to the new instruction first.
      Result->takeName(I);

      // Insert the new instruction into the basic block...
      BasicBlock *InstParent = I->getParent();
      BasicBlock::iterator InsertPos = I->getIterator();

      // Are we replace a PHI with something that isn't a PHI, or vice versa?
      if (isa<PHINode>(Result) != isa<PHINode>(I)) {
        // We need to fix up the insertion point.
        if (isa<PHINode>(I)) // PHI -> Non-PHI
          InsertPos = InstParent->getFirstInsertionPt();
        else // Non-PHI -> PHI
          InsertPos = InstParent->getFirstNonPHI()->getIterator();
      }

      InstParent->getInstList().insert(InsertPos, Result);

      // Push the new instruction and any users onto the worklist.
      Worklist.pushUsersToWorkList(*Result);
      Worklist.push(Result);

      eraseInstFromFunction(*I);
    } else {
      LLVM_DEBUG(dbgs() << "IC: Mod = " << OrigI << '\n'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Mod = " << OrigI
 << '\n' << "    New = " << *I << '\n'
; } } while (false)
                        << "    New = " << *I << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Mod = " << OrigI
 << '\n' << "    New = " << *I << '\n'
; } } while (false);

      // If the instruction was modified, it's possible that it is now dead.
      // if so, remove it.
      if (isInstructionTriviallyDead(I, &TLI)) {
        eraseInstFromFunction(*I);
      } else {
        Worklist.pushUsersToWorkList(*I);
        Worklist.push(I);
      }
    }
    MadeIRChange = true;
  }
}

Worklist.zap();
return MadeIRChange;
3927}

3929// Track the scopes used by !alias.scope and !noalias. In a function, a
3930// @llvm.experimental.noalias.scope.decl is only useful if that scope is used
3931// by both sets. If not, the declaration of the scope can be safely omitted.
3932// The MDNode of the scope can be omitted as well for the instructions that are
3933// part of this function. We do not do that at this point, as this might become
3934// too time consuming to do.
3935class AliasScopeTracker {
SmallPtrSet<const MDNode *, 8> UsedAliasScopesAndLists;
SmallPtrSet<const MDNode *, 8> UsedNoAliasScopesAndLists;

3939public:
void analyse(Instruction *I) {
  // This seems to be faster than checking 'mayReadOrWriteMemory()'.
  if (!I->hasMetadataOtherThanDebugLoc())
    return;

  auto Track = [](Metadata *ScopeList, auto &Container) {
    const auto *MDScopeList = dyn_cast_or_null<MDNode>(ScopeList);
    if (!MDScopeList || !Container.insert(MDScopeList).second)
      return;
    for (auto &MDOperand : MDScopeList->operands())
      if (auto *MDScope = dyn_cast<MDNode>(MDOperand))
        Container.insert(MDScope);
  };

  Track(I->getMetadata(LLVMContext::MD_alias_scope), UsedAliasScopesAndLists);
  Track(I->getMetadata(LLVMContext::MD_noalias), UsedNoAliasScopesAndLists);
}

bool isNoAliasScopeDeclDead(Instruction *Inst) {
  NoAliasScopeDeclInst *Decl = dyn_cast<NoAliasScopeDeclInst>(Inst);
  if (!Decl)
    return false;

  assert(Decl->use_empty() &&(static_cast <bool> (Decl->use_empty() && "llvm.experimental.noalias.scope.decl in use ?"
) ? void (0) : __assert_fail ("Decl->use_empty() && \"llvm.experimental.noalias.scope.decl in use ?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3964, __extension__ __PRETTY_FUNCTION__))
         "llvm.experimental.noalias.scope.decl in use ?")(static_cast <bool> (Decl->use_empty() && "llvm.experimental.noalias.scope.decl in use ?"
) ? void (0) : __assert_fail ("Decl->use_empty() && \"llvm.experimental.noalias.scope.decl in use ?\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3964, __extension__ __PRETTY_FUNCTION__));
  const MDNode *MDSL = Decl->getScopeList();
  assert(MDSL->getNumOperands() == 1 &&(static_cast <bool> (MDSL->getNumOperands() == 1 &&
 "llvm.experimental.noalias.scope should refer to a single scope"
) ? void (0) : __assert_fail ("MDSL->getNumOperands() == 1 && \"llvm.experimental.noalias.scope should refer to a single scope\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3967, __extension__ __PRETTY_FUNCTION__))
         "llvm.experimental.noalias.scope should refer to a single scope")(static_cast <bool> (MDSL->getNumOperands() == 1 &&
 "llvm.experimental.noalias.scope should refer to a single scope"
) ? void (0) : __assert_fail ("MDSL->getNumOperands() == 1 && \"llvm.experimental.noalias.scope should refer to a single scope\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp"
, 3967, __extension__ __PRETTY_FUNCTION__));
  auto &MDOperand = MDSL->getOperand(0);
  if (auto *MD = dyn_cast<MDNode>(MDOperand))
    return !UsedAliasScopesAndLists.contains(MD) ||
           !UsedNoAliasScopesAndLists.contains(MD);

  // Not an MDNode ? throw away.
  return true;
}
3976};

3978/// Populate the IC worklist from a function, by walking it in depth-first
3979/// order and adding all reachable code to the worklist.
3980///
3981/// This has a couple of tricks to make the code faster and more powerful.  In
3982/// particular, we constant fold and DCE instructions as we go, to avoid adding
3983/// them to the worklist (this significantly speeds up instcombine on code where
3984/// many instructions are dead or constant).  Additionally, if we find a branch
3985/// whose condition is a known constant, we only visit the reachable successors.
3986static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
                                        const TargetLibraryInfo *TLI,
                                        InstCombineWorklist &ICWorklist) {
bool MadeIRChange = false;
SmallPtrSet<BasicBlock *, 32> Visited;
SmallVector<BasicBlock*, 256> Worklist;
Worklist.push_back(&F.front());

SmallVector<Instruction*, 128> InstrsForInstCombineWorklist;
DenseMap<Constant *, Constant *> FoldedConstants;
AliasScopeTracker SeenAliasScopes;

do {
  BasicBlock *BB = Worklist.pop_back_val();

  // We have now visited this block!  If we've already been here, ignore it.
  if (!Visited.insert(BB).second)
    continue;

  for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
    Instruction *Inst = &*BBI++;

    // ConstantProp instruction if trivially constant.
    if (!Inst->use_empty() &&
        (Inst->getNumOperands() == 0 || isa<Constant>(Inst->getOperand(0))))
      if (Constant *C = ConstantFoldInstruction(Inst, DL, TLI)) {
        LLVM_DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: " << *Instdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold to: " <<
 *C << " from: " << *Inst << '\n'; } } while
 (false)
                          << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold to: " <<
 *C << " from: " << *Inst << '\n'; } } while
 (false);
        Inst->replaceAllUsesWith(C);
        ++NumConstProp;
        if (isInstructionTriviallyDead(Inst, TLI))
          Inst->eraseFromParent();
        MadeIRChange = true;
        continue;
      }

    // See if we can constant fold its operands.
    for (Use &U : Inst->operands()) {
      if (!isa<ConstantVector>(U) && !isa<ConstantExpr>(U))
        continue;

      auto *C = cast<Constant>(U);
      Constant *&FoldRes = FoldedConstants[C];
      if (!FoldRes)
        FoldRes = ConstantFoldConstant(C, DL, TLI);

      if (FoldRes != C) {
        LLVM_DEBUG(dbgs() << "IC: ConstFold operand of: " << *Instdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold operand of: "
 << *Inst << "\n    Old = " << *C << "\n    New = "
 << *FoldRes << '\n'; } } while (false)
                          << "\n    Old = " << *Cdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold operand of: "
 << *Inst << "\n    Old = " << *C << "\n    New = "
 << *FoldRes << '\n'; } } while (false)
                          << "\n    New = " << *FoldRes << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ConstFold operand of: "
 << *Inst << "\n    Old = " << *C << "\n    New = "
 << *FoldRes << '\n'; } } while (false);
        U = FoldRes;
        MadeIRChange = true;
      }
    }

    // Skip processing debug and pseudo intrinsics in InstCombine. Processing
    // these call instructions consumes non-trivial amount of time and
    // provides no value for the optimization.
    if (!Inst->isDebugOrPseudoInst()) {
      InstrsForInstCombineWorklist.push_back(Inst);
      SeenAliasScopes.analyse(Inst);
    }
  }

  // Recursively visit successors.  If this is a branch or switch on a
  // constant, only visit the reachable successor.
  Instruction *TI = BB->getTerminator();
  if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
    if (BI->isConditional() && isa<ConstantInt>(BI->getCondition())) {
      bool CondVal = cast<ConstantInt>(BI->getCondition())->getZExtValue();
      BasicBlock *ReachableBB = BI->getSuccessor(!CondVal);
      Worklist.push_back(ReachableBB);
      continue;
    }
  } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
    if (ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition())) {
      Worklist.push_back(SI->findCaseValue(Cond)->getCaseSuccessor());
      continue;
    }
  }

  append_range(Worklist, successors(TI));
} while (!Worklist.empty());

// Remove instructions inside unreachable blocks. This prevents the
// instcombine code from having to deal with some bad special cases, and
// reduces use counts of instructions.
for (BasicBlock &BB : F) {
  if (Visited.count(&BB))
    continue;

  unsigned NumDeadInstInBB;
  unsigned NumDeadDbgInstInBB;
  std::tie(NumDeadInstInBB, NumDeadDbgInstInBB) =
      removeAllNonTerminatorAndEHPadInstructions(&BB);

  MadeIRChange |= NumDeadInstInBB + NumDeadDbgInstInBB > 0;
  NumDeadInst += NumDeadInstInBB;
}

// Once we've found all of the instructions to add to instcombine's worklist,
// add them in reverse order.  This way instcombine will visit from the top
// of the function down.  This jives well with the way that it adds all uses
// of instructions to the worklist after doing a transformation, thus avoiding
// some N^2 behavior in pathological cases.
ICWorklist.reserve(InstrsForInstCombineWorklist.size());
for (Instruction *Inst : reverse(InstrsForInstCombineWorklist)) {
  // DCE instruction if trivially dead. As we iterate in reverse program
  // order here, we will clean up whole chains of dead instructions.
  if (isInstructionTriviallyDead(Inst, TLI) ||
      SeenAliasScopes.isNoAliasScopeDeclDead(Inst)) {
    ++NumDeadInst;
    LLVM_DEBUG(dbgs() << "IC: DCE: " << *Inst << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: DCE: " << *Inst
 << '\n'; } } while (false);
    salvageDebugInfo(*Inst);
    Inst->eraseFromParent();
    MadeIRChange = true;
    continue;
  }

  ICWorklist.push(Inst);
}

return MadeIRChange;
4109}

4111static bool combineInstructionsOverFunction(
  Function &F, InstCombineWorklist &Worklist, AliasAnalysis *AA,
  AssumptionCache &AC, TargetLibraryInfo &TLI, TargetTransformInfo &TTI,
  DominatorTree &DT, OptimizationRemarkEmitter &ORE, BlockFrequencyInfo *BFI,
  ProfileSummaryInfo *PSI, unsigned MaxIterations, LoopInfo *LI) {
auto &DL = F.getParent()->getDataLayout();
MaxIterations = std::min(MaxIterations, LimitMaxIterations.getValue());

/// Builder - This is an IRBuilder that automatically inserts new
/// instructions into the worklist when they are created.
IRBuilder<TargetFolder, IRBuilderCallbackInserter> Builder(
    F.getContext(), TargetFolder(DL),
    IRBuilderCallbackInserter([&Worklist, &AC](Instruction *I) {
      Worklist.add(I);
      if (auto *Assume = dyn_cast<AssumeInst>(I))
        AC.registerAssumption(Assume);
    }));

// Lower dbg.declare intrinsics otherwise their value may be clobbered
// by instcombiner.
bool MadeIRChange = false;
if (ShouldLowerDbgDeclare)
  MadeIRChange = LowerDbgDeclare(F);

// Iterate while there is work to do.
unsigned Iteration = 0;
while (true) {
  ++NumWorklistIterations;
  ++Iteration;

  if (Iteration > InfiniteLoopDetectionThreshold) {
    report_fatal_error(
        "Instruction Combining seems stuck in an infinite loop after " +
        Twine(InfiniteLoopDetectionThreshold) + " iterations.");
  }

  if (Iteration > MaxIterations) {
    LLVM_DEBUG(dbgs() << "\n\n[IC] Iteration limit #" << MaxIterationsdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "\n\n[IC] Iteration limit #"
 << MaxIterations << " on " << F.getName() <<
 " reached; stopping before reaching a fixpoint\n"; } } while
 (false)
                      << " on " << F.getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "\n\n[IC] Iteration limit #"
 << MaxIterations << " on " << F.getName() <<
 " reached; stopping before reaching a fixpoint\n"; } } while
 (false)
                      << " reached; stopping before reaching a fixpoint\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "\n\n[IC] Iteration limit #"
 << MaxIterations << " on " << F.getName() <<
 " reached; stopping before reaching a fixpoint\n"; } } while
 (false);
    break;
  }

  LLVM_DEBUG(dbgs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "\n\nINSTCOMBINE ITERATION #"
 << Iteration << " on " << F.getName() <<
 "\n"; } } while (false)
                    << F.getName() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "\n\nINSTCOMBINE ITERATION #"
 << Iteration << " on " << F.getName() <<
 "\n"; } } while (false);

  MadeIRChange |= prepareICWorklistFromFunction(F, DL, &TLI, Worklist);

  InstCombinerImpl IC(Worklist, Builder, F.hasMinSize(), AA, AC, TLI, TTI, DT,
                      ORE, BFI, PSI, DL, LI);
  IC.MaxArraySizeForCombine = MaxArraySize;

  if (!IC.run())
    break;

  MadeIRChange = true;
}

return MadeIRChange;
4170}

4172InstCombinePass::InstCombinePass() : MaxIterations(LimitMaxIterations) {}

4174InstCombinePass::InstCombinePass(unsigned MaxIterations)
  : MaxIterations(MaxIterations) {}

4177PreservedAnalyses InstCombinePass::run(Function &F,
                                     FunctionAnalysisManager &AM) {
auto &AC = AM.getResult<AssumptionAnalysis>(F);
auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
auto &TTI = AM.getResult<TargetIRAnalysis>(F);

auto *LI = AM.getCachedResult<LoopAnalysis>(F);

auto *AA = &AM.getResult<AAManager>(F);
auto &MAMProxy = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
ProfileSummaryInfo *PSI =
    MAMProxy.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
auto *BFI = (PSI && PSI->hasProfileSummary()) ?
    &AM.getResult<BlockFrequencyAnalysis>(F) : nullptr;

if (!combineInstructionsOverFunction(F, Worklist, AA, AC, TLI, TTI, DT, ORE,
                                     BFI, PSI, MaxIterations, LI))
  // No changes, all analyses are preserved.
  return PreservedAnalyses::all();

// Mark all the analyses that instcombine updates as preserved.
PreservedAnalyses PA;
PA.preserveSet<CFGAnalyses>();
return PA;
4203}

4205void InstructionCombiningPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
AU.addRequired<TargetTransformInfoWrapperPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<AAResultsWrapperPass>();
AU.addPreserved<BasicAAWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
AU.addRequired<ProfileSummaryInfoWrapperPass>();
LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AU);
4219}

4221bool InstructionCombiningPass::runOnFunction(Function &F) {
if (skipFunction(F))
  return false;

// Required analyses.
auto AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto &ORE = getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();

// Optional analyses.
auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
ProfileSummaryInfo *PSI =
    &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
BlockFrequencyInfo *BFI =
    (PSI && PSI->hasProfileSummary()) ?
    &getAnalysis<LazyBlockFrequencyInfoPass>().getBFI() :
    nullptr;

return combineInstructionsOverFunction(F, Worklist, AA, AC, TLI, TTI, DT, ORE,
                                       BFI, PSI, MaxIterations, LI);
4245}

4247char InstructionCombiningPass::ID = 0;

4249InstructionCombiningPass::InstructionCombiningPass()
  : FunctionPass(ID), MaxIterations(InstCombineDefaultMaxIterations) {
initializeInstructionCombiningPassPass(*PassRegistry::getPassRegistry());
4252}

4254InstructionCombiningPass::InstructionCombiningPass(unsigned MaxIterations)
  : FunctionPass(ID), MaxIterations(MaxIterations) {
initializeInstructionCombiningPassPass(*PassRegistry::getPassRegistry());
4257}

4259INITIALIZE_PASS_BEGIN(InstructionCombiningPass, "instcombine",static void *initializeInstructionCombiningPassPassOnce(PassRegistry
 &Registry) {
                    "Combine redundant instructions", false, false)static void *initializeInstructionCombiningPassPassOnce(PassRegistry
 &Registry) {
4261INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
4262INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
4263INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
4264INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
4265INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
4266INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)initializeGlobalsAAWrapperPassPass(Registry);
4267INITIALIZE_PASS_DEPENDENCY(OptimizationRemarkEmitterWrapperPass)initializeOptimizationRemarkEmitterWrapperPassPass(Registry);
4268INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass)initializeLazyBlockFrequencyInfoPassPass(Registry);
4269INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry);
4270INITIALIZE_PASS_END(InstructionCombiningPass, "instcombine",PassInfo *PI = new PassInfo( "Combine redundant instructions"
, "instcombine", &InstructionCombiningPass::ID, PassInfo::
NormalCtor_t(callDefaultCtor<InstructionCombiningPass>)
, false, false); Registry.registerPass(*PI, true); return PI;
 } static llvm::once_flag InitializeInstructionCombiningPassPassFlag
; void llvm::initializeInstructionCombiningPassPass(PassRegistry
 &Registry) { llvm::call_once(InitializeInstructionCombiningPassPassFlag
, initializeInstructionCombiningPassPassOnce, std::ref(Registry
)); }
                  "Combine redundant instructions", false, false)PassInfo *PI = new PassInfo( "Combine redundant instructions"
, "instcombine", &InstructionCombiningPass::ID, PassInfo::
NormalCtor_t(callDefaultCtor<InstructionCombiningPass>)
, false, false); Registry.registerPass(*PI, true); return PI;
 } static llvm::once_flag InitializeInstructionCombiningPassPassFlag
; void llvm::initializeInstructionCombiningPassPass(PassRegistry
 &Registry) { llvm::call_once(InitializeInstructionCombiningPassPassFlag
, initializeInstructionCombiningPassPassOnce, std::ref(Registry
)); }

4273// Initialization Routines
4274void llvm::initializeInstCombine(PassRegistry &Registry) {
initializeInstructionCombiningPassPass(Registry);
4276}

4278void LLVMInitializeInstCombine(LLVMPassRegistryRef R) {
initializeInstructionCombiningPassPass(*unwrap(R));
4280}

4282FunctionPass *llvm::createInstructionCombiningPass() {
return new InstructionCombiningPass();
4284}

4286FunctionPass *llvm::createInstructionCombiningPass(unsigned MaxIterations) {
return new InstructionCombiningPass(MaxIterations);
4288}

4290void LLVMAddInstructionCombiningPass(LLVMPassManagerRef PM) {
unwrap(PM)->add(createInstructionCombiningPass());
4292}

←

/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstCombineInternal.h

→

1//===- InstCombineInternal.h - InstCombine pass internals -------*- 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/// \file
10///
11/// This file provides internal interfaces used to implement the InstCombine.
12//
13//===----------------------------------------------------------------------===//

15#ifndef LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
16#define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H

18#include "llvm/ADT/Statistic.h"
19#include "llvm/Analysis/InstructionSimplify.h"
20#include "llvm/Analysis/TargetFolder.h"
21#include "llvm/Analysis/ValueTracking.h"
22#include "llvm/IR/IRBuilder.h"
23#include "llvm/IR/InstVisitor.h"
24#include "llvm/IR/PatternMatch.h"
25#include "llvm/IR/Value.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/Support/KnownBits.h"
28#include "llvm/Transforms/InstCombine/InstCombineWorklist.h"
29#include "llvm/Transforms/InstCombine/InstCombiner.h"
30#include "llvm/Transforms/Utils/Local.h"
31#include <cassert>

33#define DEBUG_TYPE"instcombine" "instcombine"

35using namespace llvm::PatternMatch;

37// As a default, let's assume that we want to be aggressive,
38// and attempt to traverse with no limits in attempt to sink negation.
39static constexpr unsigned NegatorDefaultMaxDepth = ~0U;

41// Let's guesstimate that most often we will end up visiting/producing
42// fairly small number of new instructions.
43static constexpr unsigned NegatorMaxNodesSSO = 16;

45namespace llvm {

47class AAResults;
48class APInt;
49class AssumptionCache;
50class BlockFrequencyInfo;
51class DataLayout;
52class DominatorTree;
53class GEPOperator;
54class GlobalVariable;
55class LoopInfo;
56class OptimizationRemarkEmitter;
57class ProfileSummaryInfo;
58class TargetLibraryInfo;
59class User;

61class LLVM_LIBRARY_VISIBILITY__attribute__ ((visibility("hidden"))) InstCombinerImpl final
  : public InstCombiner,
    public InstVisitor<InstCombinerImpl, Instruction *> {
64public:
InstCombinerImpl(InstCombineWorklist &Worklist, BuilderTy &Builder,
                 bool MinimizeSize, AAResults *AA, AssumptionCache &AC,
                 TargetLibraryInfo &TLI, TargetTransformInfo &TTI,
                 DominatorTree &DT, OptimizationRemarkEmitter &ORE,
                 BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI,
                 const DataLayout &DL, LoopInfo *LI)
    : InstCombiner(Worklist, Builder, MinimizeSize, AA, AC, TLI, TTI, DT, ORE,
                   BFI, PSI, DL, LI) {}

virtual ~InstCombinerImpl() {}

/// Run the combiner over the entire worklist until it is empty.
///
/// \returns true if the IR is changed.
bool run();

// Visitation implementation - Implement instruction combining for different
// instruction types.  The semantics are as follows:
// Return Value:
//    null        - No change was made
//     I          - Change was made, I is still valid, I may be dead though
//   otherwise    - Change was made, replace I with returned instruction
//
Instruction *visitFNeg(UnaryOperator &I);
Instruction *visitAdd(BinaryOperator &I);
Instruction *visitFAdd(BinaryOperator &I);
Value *OptimizePointerDifference(
    Value *LHS, Value *RHS, Type *Ty, bool isNUW);
Instruction *visitSub(BinaryOperator &I);
Instruction *visitFSub(BinaryOperator &I);
Instruction *visitMul(BinaryOperator &I);
Instruction *visitFMul(BinaryOperator &I);
Instruction *visitURem(BinaryOperator &I);
Instruction *visitSRem(BinaryOperator &I);
Instruction *visitFRem(BinaryOperator &I);
bool simplifyDivRemOfSelectWithZeroOp(BinaryOperator &I);
Instruction *commonIRemTransforms(BinaryOperator &I);
Instruction *commonIDivTransforms(BinaryOperator &I);
Instruction *visitUDiv(BinaryOperator &I);
Instruction *visitSDiv(BinaryOperator &I);
Instruction *visitFDiv(BinaryOperator &I);
Value *simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1, bool Inverted);
Instruction *visitAnd(BinaryOperator &I);
Instruction *visitOr(BinaryOperator &I);
bool sinkNotIntoOtherHandOfAndOrOr(BinaryOperator &I);
Instruction *visitXor(BinaryOperator &I);
Instruction *visitShl(BinaryOperator &I);
Value *reassociateShiftAmtsOfTwoSameDirectionShifts(
    BinaryOperator *Sh0, const SimplifyQuery &SQ,
    bool AnalyzeForSignBitExtraction = false);
Instruction *canonicalizeCondSignextOfHighBitExtractToSignextHighBitExtract(
    BinaryOperator &I);
Instruction *foldVariableSignZeroExtensionOfVariableHighBitExtract(
    BinaryOperator &OldAShr);
Instruction *visitAShr(BinaryOperator &I);
Instruction *visitLShr(BinaryOperator &I);
Instruction *commonShiftTransforms(BinaryOperator &I);
Instruction *visitFCmpInst(FCmpInst &I);
CmpInst *canonicalizeICmpPredicate(CmpInst &I);
Instruction *visitICmpInst(ICmpInst &I);
Instruction *FoldShiftByConstant(Value *Op0, Constant *Op1,
                                 BinaryOperator &I);
Instruction *commonCastTransforms(CastInst &CI);
Instruction *commonPointerCastTransforms(CastInst &CI);
Instruction *visitTrunc(TruncInst &CI);
Instruction *visitZExt(ZExtInst &CI);
Instruction *visitSExt(SExtInst &CI);
Instruction *visitFPTrunc(FPTruncInst &CI);
Instruction *visitFPExt(CastInst &CI);
Instruction *visitFPToUI(FPToUIInst &FI);
Instruction *visitFPToSI(FPToSIInst &FI);
Instruction *visitUIToFP(CastInst &CI);
Instruction *visitSIToFP(CastInst &CI);
Instruction *visitPtrToInt(PtrToIntInst &CI);
Instruction *visitIntToPtr(IntToPtrInst &CI);
Instruction *visitBitCast(BitCastInst &CI);
Instruction *visitAddrSpaceCast(AddrSpaceCastInst &CI);
Instruction *foldItoFPtoI(CastInst &FI);
Instruction *visitSelectInst(SelectInst &SI);
Instruction *visitCallInst(CallInst &CI);
Instruction *visitInvokeInst(InvokeInst &II);
Instruction *visitCallBrInst(CallBrInst &CBI);

Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
Instruction *visitPHINode(PHINode &PN);
Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
Instruction *visitAllocaInst(AllocaInst &AI);
Instruction *visitAllocSite(Instruction &FI);
Instruction *visitFree(CallInst &FI);
Instruction *visitLoadInst(LoadInst &LI);
Instruction *visitStoreInst(StoreInst &SI);
Instruction *visitAtomicRMWInst(AtomicRMWInst &SI);
Instruction *visitUnconditionalBranchInst(BranchInst &BI);
Instruction *visitBranchInst(BranchInst &BI);
Instruction *visitFenceInst(FenceInst &FI);
Instruction *visitSwitchInst(SwitchInst &SI);
Instruction *visitReturnInst(ReturnInst &RI);
Instruction *visitUnreachableInst(UnreachableInst &I);
Instruction *
foldAggregateConstructionIntoAggregateReuse(InsertValueInst &OrigIVI);
Instruction *visitInsertValueInst(InsertValueInst &IV);
Instruction *visitInsertElementInst(InsertElementInst &IE);
Instruction *visitExtractElementInst(ExtractElementInst &EI);
Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
Instruction *visitExtractValueInst(ExtractValueInst &EV);
Instruction *visitLandingPadInst(LandingPadInst &LI);
Instruction *visitVAEndInst(VAEndInst &I);
Value *pushFreezeToPreventPoisonFromPropagating(FreezeInst &FI);
bool freezeDominatedUses(FreezeInst &FI);
Instruction *visitFreeze(FreezeInst &I);

/// Specify what to return for unhandled instructions.
Instruction *visitInstruction(Instruction &I) { return nullptr; }

/// True when DB dominates all uses of DI except UI.
/// UI must be in the same block as DI.
/// The routine checks that the DI parent and DB are different.
bool dominatesAllUses(const Instruction *DI, const Instruction *UI,
                      const BasicBlock *DB) const;

/// Try to replace select with select operand SIOpd in SI-ICmp sequence.
bool replacedSelectWithOperand(SelectInst *SI, const ICmpInst *Icmp,
                               const unsigned SIOpd);

LoadInst *combineLoadToNewType(LoadInst &LI, Type *NewTy,
                               const Twine &Suffix = "");

192private:
void annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI);
bool shouldChangeType(unsigned FromBitWidth, unsigned ToBitWidth) const;
bool shouldChangeType(Type *From, Type *To) const;
Value *dyn_castNegVal(Value *V) const;
Type *FindElementAtOffset(PointerType *PtrTy, int64_t Offset,
                          SmallVectorImpl<Value *> &NewIndices);

/// Classify whether a cast is worth optimizing.
///
/// This is a helper to decide whether the simplification of
/// logic(cast(A), cast(B)) to cast(logic(A, B)) should be performed.
///
/// \param CI The cast we are interested in.
///
/// \return true if this cast actually results in any code being generated and
/// if it cannot already be eliminated by some other transformation.
bool shouldOptimizeCast(CastInst *CI);

/// Try to optimize a sequence of instructions checking if an operation
/// on LHS and RHS overflows.
///
/// If this overflow check is done via one of the overflow check intrinsics,
/// then CtxI has to be the call instruction calling that intrinsic.  If this
/// overflow check is done by arithmetic followed by a compare, then CtxI has
/// to be the arithmetic instruction.
///
/// If a simplification is possible, stores the simplified result of the
/// operation in OperationResult and result of the overflow check in
/// OverflowResult, and return true.  If no simplification is possible,
/// returns false.
bool OptimizeOverflowCheck(Instruction::BinaryOps BinaryOp, bool IsSigned,
                           Value *LHS, Value *RHS,
                           Instruction &CtxI, Value *&OperationResult,
                           Constant *&OverflowResult);

Instruction *visitCallBase(CallBase &Call);
Instruction *tryOptimizeCall(CallInst *CI);
bool transformConstExprCastCall(CallBase &Call);
Instruction *transformCallThroughTrampoline(CallBase &Call,
                                            IntrinsicInst &Tramp);

Value *simplifyMaskedLoad(IntrinsicInst &II);
Instruction *simplifyMaskedStore(IntrinsicInst &II);
Instruction *simplifyMaskedGather(IntrinsicInst &II);
Instruction *simplifyMaskedScatter(IntrinsicInst &II);

/// Transform (zext icmp) to bitwise / integer operations in order to
/// eliminate it.
///
/// \param ICI The icmp of the (zext icmp) pair we are interested in.
/// \parem CI The zext of the (zext icmp) pair we are interested in.
/// \param DoTransform Pass false to just test whether the given (zext icmp)
/// would be transformed. Pass true to actually perform the transformation.
///
/// \return null if the transformation cannot be performed. If the
/// transformation can be performed the new instruction that replaces the
/// (zext icmp) pair will be returned (if \p DoTransform is false the
/// unmodified \p ICI will be returned in this case).
Instruction *transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
                               bool DoTransform = true);

Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);

bool willNotOverflowSignedAdd(const Value *LHS, const Value *RHS,
                              const Instruction &CxtI) const {
  return computeOverflowForSignedAdd(LHS, RHS, &CxtI) ==
         OverflowResult::NeverOverflows;
}

bool willNotOverflowUnsignedAdd(const Value *LHS, const Value *RHS,
                                const Instruction &CxtI) const {
  return computeOverflowForUnsignedAdd(LHS, RHS, &CxtI) ==
         OverflowResult::NeverOverflows;
}

bool willNotOverflowAdd(const Value *LHS, const Value *RHS,
                        const Instruction &CxtI, bool IsSigned) const {
  return IsSigned ? willNotOverflowSignedAdd(LHS, RHS, CxtI)
                  : willNotOverflowUnsignedAdd(LHS, RHS, CxtI);
}

bool willNotOverflowSignedSub(const Value *LHS, const Value *RHS,
                              const Instruction &CxtI) const {
  return computeOverflowForSignedSub(LHS, RHS, &CxtI) ==
         OverflowResult::NeverOverflows;
}

bool willNotOverflowUnsignedSub(const Value *LHS, const Value *RHS,
                                const Instruction &CxtI) const {
  return computeOverflowForUnsignedSub(LHS, RHS, &CxtI) ==
         OverflowResult::NeverOverflows;
}

bool willNotOverflowSub(const Value *LHS, const Value *RHS,
                        const Instruction &CxtI, bool IsSigned) const {
  return IsSigned ? willNotOverflowSignedSub(LHS, RHS, CxtI)
                  : willNotOverflowUnsignedSub(LHS, RHS, CxtI);
}

bool willNotOverflowSignedMul(const Value *LHS, const Value *RHS,
                              const Instruction &CxtI) const {
  return computeOverflowForSignedMul(LHS, RHS, &CxtI) ==
         OverflowResult::NeverOverflows;
}

bool willNotOverflowUnsignedMul(const Value *LHS, const Value *RHS,
                                const Instruction &CxtI) const {
  return computeOverflowForUnsignedMul(LHS, RHS, &CxtI) ==
         OverflowResult::NeverOverflows;
}

bool willNotOverflowMul(const Value *LHS, const Value *RHS,
                        const Instruction &CxtI, bool IsSigned) const {
  return IsSigned ? willNotOverflowSignedMul(LHS, RHS, CxtI)
                  : willNotOverflowUnsignedMul(LHS, RHS, CxtI);
}

bool willNotOverflow(BinaryOperator::BinaryOps Opcode, const Value *LHS,
                     const Value *RHS, const Instruction &CxtI,
                     bool IsSigned) const {
  switch (Opcode) {
  case Instruction::Add: return willNotOverflowAdd(LHS, RHS, CxtI, IsSigned);
  case Instruction::Sub: return willNotOverflowSub(LHS, RHS, CxtI, IsSigned);
  case Instruction::Mul: return willNotOverflowMul(LHS, RHS, CxtI, IsSigned);
  default: llvm_unreachable("Unexpected opcode for overflow query")::llvm::llvm_unreachable_internal("Unexpected opcode for overflow query"
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstCombineInternal.h"
, 317);
  }
}

Value *EmitGEPOffset(User *GEP);
Instruction *scalarizePHI(ExtractElementInst &EI, PHINode *PN);
Instruction *foldCastedBitwiseLogic(BinaryOperator &I);
Instruction *narrowBinOp(TruncInst &Trunc);
Instruction *narrowMaskedBinOp(BinaryOperator &And);
Instruction *narrowMathIfNoOverflow(BinaryOperator &I);
Instruction *narrowFunnelShift(TruncInst &Trunc);
Instruction *optimizeBitCastFromPhi(CastInst &CI, PHINode *PN);
Instruction *matchSAddSubSat(Instruction &MinMax1);

void freelyInvertAllUsersOf(Value *V);

/// Determine if a pair of casts can be replaced by a single cast.
///
/// \param CI1 The first of a pair of casts.
/// \param CI2 The second of a pair of casts.
///
/// \return 0 if the cast pair cannot be eliminated, otherwise returns an
/// Instruction::CastOps value for a cast that can replace the pair, casting
/// CI1->getSrcTy() to CI2->getDstTy().
///
/// \see CastInst::isEliminableCastPair
Instruction::CastOps isEliminableCastPair(const CastInst *CI1,
                                          const CastInst *CI2);
Value *simplifyIntToPtrRoundTripCast(Value *Val);

Value *foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS, BinaryOperator &And);
Value *foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, BinaryOperator &Or);
Value *foldXorOfICmps(ICmpInst *LHS, ICmpInst *RHS, BinaryOperator &Xor);

Value *foldEqOfParts(ICmpInst *Cmp0, ICmpInst *Cmp1, bool IsAnd);

/// Optimize (fcmp)&(fcmp) or (fcmp)|(fcmp).
/// NOTE: Unlike most of instcombine, this returns a Value which should
/// already be inserted into the function.
Value *foldLogicOfFCmps(FCmpInst *LHS, FCmpInst *RHS, bool IsAnd);

Value *foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS, ICmpInst *RHS,
                                     Instruction *CxtI, bool IsAnd,
                                     bool IsLogical = false);
Value *matchSelectFromAndOr(Value *A, Value *B, Value *C, Value *D);
Value *getSelectCondition(Value *A, Value *B);

Instruction *foldIntrinsicWithOverflowCommon(IntrinsicInst *II);
Instruction *foldFPSignBitOps(BinaryOperator &I);

// Optimize one of these forms:
//   and i1 Op, SI / select i1 Op, i1 SI, i1 false (if IsAnd = true)
//   or i1 Op, SI  / select i1 Op, i1 true, i1 SI  (if IsAnd = false)
// into simplier select instruction using isImpliedCondition.
Instruction *foldAndOrOfSelectUsingImpliedCond(Value *Op, SelectInst &SI,
                                               bool IsAnd);

374public:
/// Inserts an instruction \p New before instruction \p Old
///
/// Also adds the new instruction to the worklist and returns \p New so that
/// it is suitable for use as the return from the visitation patterns.
Instruction *InsertNewInstBefore(Instruction *New, Instruction &Old) {
  assert(New && !New->getParent() &&(static_cast <bool> (New && !New->getParent(
) && "New instruction already inserted into a basic block!"
) ? void (0) : __assert_fail ("New && !New->getParent() && \"New instruction already inserted into a basic block!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstCombineInternal.h"
, 381, __extension__ __PRETTY_FUNCTION__))
         "New instruction already inserted into a basic block!")(static_cast <bool> (New && !New->getParent(
) && "New instruction already inserted into a basic block!"
) ? void (0) : __assert_fail ("New && !New->getParent() && \"New instruction already inserted into a basic block!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstCombineInternal.h"
, 381, __extension__ __PRETTY_FUNCTION__));
  BasicBlock *BB = Old.getParent();
  BB->getInstList().insert(Old.getIterator(), New); // Insert inst
  Worklist.add(New);
  return New;
}

/// Same as InsertNewInstBefore, but also sets the debug loc.
Instruction *InsertNewInstWith(Instruction *New, Instruction &Old) {
  New->setDebugLoc(Old.getDebugLoc());
  return InsertNewInstBefore(New, Old);
}

/// A combiner-aware RAUW-like routine.
///
/// This method is to be used when an instruction is found to be dead,
/// replaceable with another preexisting expression. Here we add all uses of
/// I to the worklist, replace all uses of I with the new value, then return
/// I, so that the inst combiner will know that I was modified.
Instruction *replaceInstUsesWith(Instruction &I, Value *V) {
  // If there are no uses to replace, then we return nullptr to indicate that
  // no changes were made to the program.
  if (I.use_empty()) return nullptr;
15
←
Calling 'Value::use_empty'→
18
←
Returning from 'Value::use_empty'→
19
←
Taking false branch→

  Worklist.pushUsersToWorkList(I); // Add all modified instrs to worklist.

  // If we are replacing the instruction with itself, this must be in a
  // segment of unreachable code, so just clobber the instruction.
  if (&I == V)
    V = UndefValue::get(I.getType());

  LLVM_DEBUG(dbgs() << "IC: Replacing " << I << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Replacing " << I
 << "\n" << "    with " << *V << '\n'
; } } while (false)
20
←
Taking false branch→
21
←
Assuming 'DebugFlag' is true→
22
←
Assuming the condition is true→
23
←
Taking true branch→
24
←
Forming reference to null pointer
                    << "    with " << *V << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: Replacing " << I
 << "\n" << "    with " << *V << '\n'
; } } while (false);

  I.replaceAllUsesWith(V);
  MadeIRChange = true;
  return &I;
}

/// Replace operand of instruction and add old operand to the worklist.
Instruction *replaceOperand(Instruction &I, unsigned OpNum, Value *V) {
  Worklist.addValue(I.getOperand(OpNum));
  I.setOperand(OpNum, V);
  return &I;
}

/// Replace use and add the previously used value to the worklist.
void replaceUse(Use &U, Value *NewValue) {
  Worklist.addValue(U);
  U = NewValue;
}

/// Create and insert the idiom we use to indicate a block is unreachable
/// without having to rewrite the CFG from within InstCombine.
void CreateNonTerminatorUnreachable(Instruction *InsertAt) {
  auto &Ctx = InsertAt->getContext();
  new StoreInst(ConstantInt::getTrue(Ctx),
                UndefValue::get(Type::getInt1PtrTy(Ctx)),
                InsertAt);
}


/// Combiner aware instruction erasure.
///
/// When dealing with an instruction that has side effects or produces a void
/// value, we can't rely on DCE to delete the instruction. Instead, visit
/// methods should return the value returned by this function.
Instruction *eraseInstFromFunction(Instruction &I) override {
  LLVM_DEBUG(dbgs() << "IC: ERASE " << I << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("instcombine")) { dbgs() << "IC: ERASE " << I <<
 '\n'; } } while (false);
  assert(I.use_empty() && "Cannot erase instruction that is used!")(static_cast <bool> (I.use_empty() && "Cannot erase instruction that is used!"
) ? void (0) : __assert_fail ("I.use_empty() && \"Cannot erase instruction that is used!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/lib/Transforms/InstCombine/InstCombineInternal.h"
, 450, __extension__ __PRETTY_FUNCTION__));
  salvageDebugInfo(I);

  // Make sure that we reprocess all operands now that we reduced their
  // use counts.
  for (Use &Operand : I.operands())
    if (auto *Inst = dyn_cast<Instruction>(Operand))
      Worklist.add(Inst);

  Worklist.remove(&I);
  I.eraseFromParent();
  MadeIRChange = true;
  return nullptr; // Don't do anything with FI
}

void computeKnownBits(const Value *V, KnownBits &Known,
                      unsigned Depth, const Instruction *CxtI) const {
  llvm::computeKnownBits(V, Known, DL, Depth, &AC, CxtI, &DT);
}

KnownBits computeKnownBits(const Value *V, unsigned Depth,
                           const Instruction *CxtI) const {
  return llvm::computeKnownBits(V, DL, Depth, &AC, CxtI, &DT);
}

bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero = false,
                            unsigned Depth = 0,
                            const Instruction *CxtI = nullptr) {
  return llvm::isKnownToBeAPowerOfTwo(V, DL, OrZero, Depth, &AC, CxtI, &DT);
}

bool MaskedValueIsZero(const Value *V, const APInt &Mask, unsigned Depth = 0,
                       const Instruction *CxtI = nullptr) const {
  return llvm::MaskedValueIsZero(V, Mask, DL, Depth, &AC, CxtI, &DT);
}

unsigned ComputeNumSignBits(const Value *Op, unsigned Depth = 0,
                            const Instruction *CxtI = nullptr) const {
  return llvm::ComputeNumSignBits(Op, DL, Depth, &AC, CxtI, &DT);
}

OverflowResult computeOverflowForUnsignedMul(const Value *LHS,
                                             const Value *RHS,
                                             const Instruction *CxtI) const {
  return llvm::computeOverflowForUnsignedMul(LHS, RHS, DL, &AC, CxtI, &DT);
}

OverflowResult computeOverflowForSignedMul(const Value *LHS,
                                           const Value *RHS,
                                           const Instruction *CxtI) const {
  return llvm::computeOverflowForSignedMul(LHS, RHS, DL, &AC, CxtI, &DT);
}

OverflowResult computeOverflowForUnsignedAdd(const Value *LHS,
                                             const Value *RHS,
                                             const Instruction *CxtI) const {
  return llvm::computeOverflowForUnsignedAdd(LHS, RHS, DL, &AC, CxtI, &DT);
}

OverflowResult computeOverflowForSignedAdd(const Value *LHS,
                                           const Value *RHS,
                                           const Instruction *CxtI) const {
  return llvm::computeOverflowForSignedAdd(LHS, RHS, DL, &AC, CxtI, &DT);
}

OverflowResult computeOverflowForUnsignedSub(const Value *LHS,
                                             const Value *RHS,
                                             const Instruction *CxtI) const {
  return llvm::computeOverflowForUnsignedSub(LHS, RHS, DL, &AC, CxtI, &DT);
}

OverflowResult computeOverflowForSignedSub(const Value *LHS, const Value *RHS,
                                           const Instruction *CxtI) const {
  return llvm::computeOverflowForSignedSub(LHS, RHS, DL, &AC, CxtI, &DT);
}

OverflowResult computeOverflow(
    Instruction::BinaryOps BinaryOp, bool IsSigned,
    Value *LHS, Value *RHS, Instruction *CxtI) const;

/// Performs a few simplifications for operators which are associative
/// or commutative.
bool SimplifyAssociativeOrCommutative(BinaryOperator &I);

/// Tries to simplify binary operations which some other binary
/// operation distributes over.
///
/// It does this by either by factorizing out common terms (eg "(A*B)+(A*C)"
/// -> "A*(B+C)") or expanding out if this results in simplifications (eg: "A
/// & (B | C) -> (A&B) | (A&C)" if this is a win).  Returns the simplified
/// value, or null if it didn't simplify.
Value *SimplifyUsingDistributiveLaws(BinaryOperator &I);

/// Tries to simplify add operations using the definition of remainder.
///
/// The definition of remainder is X % C = X - (X / C ) * C. The add
/// expression X % C0 + (( X / C0 ) % C1) * C0 can be simplified to
/// X % (C0 * C1)
Value *SimplifyAddWithRemainder(BinaryOperator &I);

// Binary Op helper for select operations where the expression can be
// efficiently reorganized.
Value *SimplifySelectsFeedingBinaryOp(BinaryOperator &I, Value *LHS,
                                      Value *RHS);

/// This tries to simplify binary operations by factorizing out common terms
/// (e. g. "(A*B)+(A*C)" -> "A*(B+C)").
Value *tryFactorization(BinaryOperator &, Instruction::BinaryOps, Value *,
                        Value *, Value *, Value *);

/// Match a select chain which produces one of three values based on whether
/// the LHS is less than, equal to, or greater than RHS respectively.
/// Return true if we matched a three way compare idiom. The LHS, RHS, Less,
/// Equal and Greater values are saved in the matching process and returned to
/// the caller.
bool matchThreeWayIntCompare(SelectInst *SI, Value *&LHS, Value *&RHS,
                             ConstantInt *&Less, ConstantInt *&Equal,
                             ConstantInt *&Greater);

/// Attempts to replace V with a simpler value based on the demanded
/// bits.
Value *SimplifyDemandedUseBits(Value *V, APInt DemandedMask, KnownBits &Known,
                               unsigned Depth, Instruction *CxtI);
bool SimplifyDemandedBits(Instruction *I, unsigned Op,
                          const APInt &DemandedMask, KnownBits &Known,
                          unsigned Depth = 0) override;

/// Helper routine of SimplifyDemandedUseBits. It computes KnownZero/KnownOne
/// bits. It also tries to handle simplifications that can be done based on
/// DemandedMask, but without modifying the Instruction.
Value *SimplifyMultipleUseDemandedBits(Instruction *I,
                                       const APInt &DemandedMask,
                                       KnownBits &Known,
                                       unsigned Depth, Instruction *CxtI);

/// Helper routine of SimplifyDemandedUseBits. It tries to simplify demanded
/// bit for "r1 = shr x, c1; r2 = shl r1, c2" instruction sequence.
Value *simplifyShrShlDemandedBits(
    Instruction *Shr, const APInt &ShrOp1, Instruction *Shl,
    const APInt &ShlOp1, const APInt &DemandedMask, KnownBits &Known);

/// Tries to simplify operands to an integer instruction based on its
/// demanded bits.
bool SimplifyDemandedInstructionBits(Instruction &Inst);

virtual Value *
SimplifyDemandedVectorElts(Value *V, APInt DemandedElts, APInt &UndefElts,
                           unsigned Depth = 0,
                           bool AllowMultipleUsers = false) override;

/// Canonicalize the position of binops relative to shufflevector.
Instruction *foldVectorBinop(BinaryOperator &Inst);
Instruction *foldVectorSelect(SelectInst &Sel);

/// Given a binary operator, cast instruction, or select which has a PHI node
/// as operand #0, see if we can fold the instruction into the PHI (which is
/// only possible if all operands to the PHI are constants).
Instruction *foldOpIntoPhi(Instruction &I, PHINode *PN);

/// Given an instruction with a select as one operand and a constant as the
/// other operand, try to fold the binary operator into the select arguments.
/// This also works for Cast instructions, which obviously do not have a
/// second operand.
Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);

/// This is a convenience wrapper function for the above two functions.
Instruction *foldBinOpIntoSelectOrPhi(BinaryOperator &I);

Instruction *foldAddWithConstant(BinaryOperator &Add);

/// Try to rotate an operation below a PHI node, using PHI nodes for
/// its operands.
Instruction *foldPHIArgOpIntoPHI(PHINode &PN);
Instruction *foldPHIArgBinOpIntoPHI(PHINode &PN);
Instruction *foldPHIArgInsertValueInstructionIntoPHI(PHINode &PN);
Instruction *foldPHIArgExtractValueInstructionIntoPHI(PHINode &PN);
Instruction *foldPHIArgGEPIntoPHI(PHINode &PN);
Instruction *foldPHIArgLoadIntoPHI(PHINode &PN);
Instruction *foldPHIArgZextsIntoPHI(PHINode &PN);
Instruction *foldPHIArgIntToPtrToPHI(PHINode &PN);

/// If an integer typed PHI has only one use which is an IntToPtr operation,
/// replace the PHI with an existing pointer typed PHI if it exists. Otherwise
/// insert a new pointer typed PHI and replace the original one.
Instruction *foldIntegerTypedPHI(PHINode &PN);

/// Helper function for FoldPHIArgXIntoPHI() to set debug location for the
/// folded operation.
void PHIArgMergedDebugLoc(Instruction *Inst, PHINode &PN);

Instruction *foldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
                         ICmpInst::Predicate Cond, Instruction &I);
Instruction *foldAllocaCmp(ICmpInst &ICI, const AllocaInst *Alloca,
                           const Value *Other);
Instruction *foldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
                                          GlobalVariable *GV, CmpInst &ICI,
                                          ConstantInt *AndCst = nullptr);
Instruction *foldFCmpIntToFPConst(FCmpInst &I, Instruction *LHSI,
                                  Constant *RHSC);
Instruction *foldICmpAddOpConst(Value *X, const APInt &C,
                                ICmpInst::Predicate Pred);
Instruction *foldICmpWithCastOp(ICmpInst &ICI);

Instruction *foldICmpUsingKnownBits(ICmpInst &Cmp);
Instruction *foldICmpWithDominatingICmp(ICmpInst &Cmp);
Instruction *foldICmpWithConstant(ICmpInst &Cmp);
Instruction *foldICmpInstWithConstant(ICmpInst &Cmp);
Instruction *foldICmpInstWithConstantNotInt(ICmpInst &Cmp);
Instruction *foldICmpBinOp(ICmpInst &Cmp, const SimplifyQuery &SQ);
Instruction *foldICmpEquality(ICmpInst &Cmp);
Instruction *foldIRemByPowerOfTwoToBitTest(ICmpInst &I);
Instruction *foldSignBitTest(ICmpInst &I);
Instruction *foldICmpWithZero(ICmpInst &Cmp);

Value *foldUnsignedMultiplicationOverflowCheck(ICmpInst &Cmp);

Instruction *foldICmpSelectConstant(ICmpInst &Cmp, SelectInst *Select,
                                    ConstantInt *C);
Instruction *foldICmpTruncConstant(ICmpInst &Cmp, TruncInst *Trunc,
                                   const APInt &C);
Instruction *foldICmpAndConstant(ICmpInst &Cmp, BinaryOperator *And,
                                 const APInt &C);
Instruction *foldICmpXorConstant(ICmpInst &Cmp, BinaryOperator *Xor,
                                 const APInt &C);
Instruction *foldICmpOrConstant(ICmpInst &Cmp, BinaryOperator *Or,
                                const APInt &C);
Instruction *foldICmpMulConstant(ICmpInst &Cmp, BinaryOperator *Mul,
                                 const APInt &C);
Instruction *foldICmpShlConstant(ICmpInst &Cmp, BinaryOperator *Shl,
                                 const APInt &C);
Instruction *foldICmpShrConstant(ICmpInst &Cmp, BinaryOperator *Shr,
                                 const APInt &C);
Instruction *foldICmpSRemConstant(ICmpInst &Cmp, BinaryOperator *UDiv,
                                  const APInt &C);
Instruction *foldICmpUDivConstant(ICmpInst &Cmp, BinaryOperator *UDiv,
                                  const APInt &C);
Instruction *foldICmpDivConstant(ICmpInst &Cmp, BinaryOperator *Div,
                                 const APInt &C);
Instruction *foldICmpSubConstant(ICmpInst &Cmp, BinaryOperator *Sub,
                                 const APInt &C);
Instruction *foldICmpAddConstant(ICmpInst &Cmp, BinaryOperator *Add,
                                 const APInt &C);
Instruction *foldICmpAndConstConst(ICmpInst &Cmp, BinaryOperator *And,
                                   const APInt &C1);
Instruction *foldICmpAndShift(ICmpInst &Cmp, BinaryOperator *And,
                              const APInt &C1, const APInt &C2);
Instruction *foldICmpShrConstConst(ICmpInst &I, Value *ShAmt, const APInt &C1,
                                   const APInt &C2);
Instruction *foldICmpShlConstConst(ICmpInst &I, Value *ShAmt, const APInt &C1,
                                   const APInt &C2);

Instruction *foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
                                               BinaryOperator *BO,
                                               const APInt &C);
Instruction *foldICmpIntrinsicWithConstant(ICmpInst &ICI, IntrinsicInst *II,
                                           const APInt &C);
Instruction *foldICmpEqIntrinsicWithConstant(ICmpInst &ICI, IntrinsicInst *II,
                                             const APInt &C);
Instruction *foldICmpBitCast(ICmpInst &Cmp);

// Helpers of visitSelectInst().
Instruction *foldSelectExtConst(SelectInst &Sel);
Instruction *foldSelectOpOp(SelectInst &SI, Instruction *TI, Instruction *FI);
Instruction *foldSelectIntoOp(SelectInst &SI, Value *, Value *);
Instruction *foldSPFofSPF(Instruction *Inner, SelectPatternFlavor SPF1,
                          Value *A, Value *B, Instruction &Outer,
                          SelectPatternFlavor SPF2, Value *C);
Instruction *foldSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
Instruction *foldSelectValueEquivalence(SelectInst &SI, ICmpInst &ICI);

Value *insertRangeTest(Value *V, const APInt &Lo, const APInt &Hi,
                       bool isSigned, bool Inside);
Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocaInst &AI);
bool mergeStoreIntoSuccessor(StoreInst &SI);

/// Given an initial instruction, check to see if it is the root of a
/// bswap/bitreverse idiom. If so, return the equivalent bswap/bitreverse
/// intrinsic.
Instruction *matchBSwapOrBitReverse(Instruction &I, bool MatchBSwaps,
                                    bool MatchBitReversals);

Instruction *SimplifyAnyMemTransfer(AnyMemTransferInst *MI);
Instruction *SimplifyAnyMemSet(AnyMemSetInst *MI);

Value *EvaluateInDifferentType(Value *V, Type *Ty, bool isSigned);

/// Returns a value X such that Val = X * Scale, or null if none.
///
/// If the multiplication is known not to overflow then NoSignedWrap is set.
Value *Descale(Value *Val, APInt Scale, bool &NoSignedWrap);
740};

742class Negator final {
/// Top-to-bottom, def-to-use negated instruction tree we produced.
SmallVector<Instruction *, NegatorMaxNodesSSO> NewInstructions;

using BuilderTy = IRBuilder<TargetFolder, IRBuilderCallbackInserter>;
BuilderTy Builder;

const DataLayout &DL;
AssumptionCache &AC;
const DominatorTree &DT;

const bool IsTrulyNegation;

SmallDenseMap<Value *, Value *> NegationsCache;

Negator(LLVMContext &C, const DataLayout &DL, AssumptionCache &AC,
        const DominatorTree &DT, bool IsTrulyNegation);

760#if LLVM_ENABLE_STATS1
unsigned NumValuesVisitedInThisNegator = 0;
~Negator();
763#endif

using Result = std::pair<ArrayRef<Instruction *> /*NewInstructions*/,
                         Value * /*NegatedRoot*/>;

std::array<Value *, 2> getSortedOperandsOfBinOp(Instruction *I);

LLVM_NODISCARD[[clang::warn_unused_result]] Value *visitImpl(Value *V, unsigned Depth);

LLVM_NODISCARD[[clang::warn_unused_result]] Value *negate(Value *V, unsigned Depth);

/// Recurse depth-first and attempt to sink the negation.
/// FIXME: use worklist?
LLVM_NODISCARD[[clang::warn_unused_result]] Optional<Result> run(Value *Root);

Negator(const Negator &) = delete;
Negator(Negator &&) = delete;
Negator &operator=(const Negator &) = delete;
Negator &operator=(Negator &&) = delete;

783public:
/// Attempt to negate \p Root. Retuns nullptr if negation can't be performed,
/// otherwise returns negated value.
LLVM_NODISCARD[[clang::warn_unused_result]] static Value *Negate(bool LHSIsZero, Value *Root,
                                    InstCombinerImpl &IC);
788};

790} // end namespace llvm

792#undef DEBUG_TYPE"instcombine"

794#endif // LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H

←

/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/IR/Value.h

1//===- llvm/Value.h - Definition of the Value class -------------*- 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 Value class.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_IR_VALUE_H
14#define LLVM_IR_VALUE_H

16#include "llvm-c/Types.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/ADT/iterator_range.h"
20#include "llvm/IR/Use.h"
21#include "llvm/Support/Alignment.h"
22#include "llvm/Support/CBindingWrapping.h"
23#include "llvm/Support/Casting.h"
24#include <cassert>
25#include <iterator>
26#include <memory>

28namespace llvm {

30class APInt;
31class Argument;
32class BasicBlock;
33class Constant;
34class ConstantData;
35class ConstantAggregate;
36class DataLayout;
37class Function;
38class GlobalAlias;
39class GlobalIFunc;
40class GlobalIndirectSymbol;
41class GlobalObject;
42class GlobalValue;
43class GlobalVariable;
44class InlineAsm;
45class Instruction;
46class LLVMContext;
47class MDNode;
48class Module;
49class ModuleSlotTracker;
50class raw_ostream;
51template<typename ValueTy> class StringMapEntry;
52class Twine;
53class Type;
54class User;

56using ValueName = StringMapEntry<Value *>;

58//===----------------------------------------------------------------------===//
59//                                 Value Class
60//===----------------------------------------------------------------------===//

62/// LLVM Value Representation
63///
64/// This is a very important LLVM class. It is the base class of all values
65/// computed by a program that may be used as operands to other values. Value is
66/// the super class of other important classes such as Instruction and Function.
67/// All Values have a Type. Type is not a subclass of Value. Some values can
68/// have a name and they belong to some Module.  Setting the name on the Value
69/// automatically updates the module's symbol table.
70///
71/// Every value has a "use list" that keeps track of which other Values are
72/// using this Value.  A Value can also have an arbitrary number of ValueHandle
73/// objects that watch it and listen to RAUW and Destroy events.  See
74/// llvm/IR/ValueHandle.h for details.
75class Value {
Type *VTy;
Use *UseList;

friend class ValueAsMetadata; // Allow access to IsUsedByMD.
friend class ValueHandleBase;

const unsigned char SubclassID;   // Subclass identifier (for isa/dyn_cast)
unsigned char HasValueHandle : 1; // Has a ValueHandle pointing to this?

85protected:
/// Hold subclass data that can be dropped.
///
/// This member is similar to SubclassData, however it is for holding
/// information which may be used to aid optimization, but which may be
/// cleared to zero without affecting conservative interpretation.
unsigned char SubclassOptionalData : 7;

93private:
/// Hold arbitrary subclass data.
///
/// This member is defined by this class, but is not used for anything.
/// Subclasses can use it to hold whatever state they find useful.  This
/// field is initialized to zero by the ctor.
unsigned short SubclassData;

101protected:
/// The number of operands in the subclass.
///
/// This member is defined by this class, but not used for anything.
/// Subclasses can use it to store their number of operands, if they have
/// any.
///
/// This is stored here to save space in User on 64-bit hosts.  Since most
/// instances of Value have operands, 32-bit hosts aren't significantly
/// affected.
///
/// Note, this should *NOT* be used directly by any class other than User.
/// User uses this value to find the Use list.
enum : unsigned { NumUserOperandsBits = 27 };
unsigned NumUserOperands : NumUserOperandsBits;

// Use the same type as the bitfield above so that MSVC will pack them.
unsigned IsUsedByMD : 1;
unsigned HasName : 1;
unsigned HasMetadata : 1; // Has metadata attached to this?
unsigned HasHungOffUses : 1;
unsigned HasDescriptor : 1;

124private:
template <typename UseT> // UseT == 'Use' or 'const Use'
class use_iterator_impl {
  friend class Value;

  UseT *U;

  explicit use_iterator_impl(UseT *u) : U(u) {}

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

  use_iterator_impl() : U() {}

  bool operator==(const use_iterator_impl &x) const { return U == x.U; }
  bool operator!=(const use_iterator_impl &x) const { return !operator==(x); }

  use_iterator_impl &operator++() { // Preincrement
    assert(U && "Cannot increment end iterator!")(static_cast <bool> (U && "Cannot increment end iterator!"
) ? void (0) : __assert_fail ("U && \"Cannot increment end iterator!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/IR/Value.h"
, 146, __extension__ __PRETTY_FUNCTION__));
    U = U->getNext();
    return *this;
  }

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

  UseT &operator*() const {
    assert(U && "Cannot dereference end iterator!")(static_cast <bool> (U && "Cannot dereference end iterator!"
) ? void (0) : __assert_fail ("U && \"Cannot dereference end iterator!\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/IR/Value.h"
, 158, __extension__ __PRETTY_FUNCTION__));
    return *U;
  }

  UseT *operator->() const { return &operator*(); }

  operator use_iterator_impl<const UseT>() const {
    return use_iterator_impl<const UseT>(U);
  }
};

template <typename UserTy> // UserTy == 'User' or 'const User'
class user_iterator_impl {
  use_iterator_impl<Use> UI;
  explicit user_iterator_impl(Use *U) : UI(U) {}
  friend class Value;

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

  user_iterator_impl() = default;

  bool operator==(const user_iterator_impl &x) const { return UI == x.UI; }
  bool operator!=(const user_iterator_impl &x) const { return !operator==(x); }

  /// Returns true if this iterator is equal to user_end() on the value.
  bool atEnd() const { return *this == user_iterator_impl(); }

  user_iterator_impl &operator++() { // Preincrement
    ++UI;
    return *this;
  }

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

  // Retrieve a pointer to the current User.
  UserTy *operator*() const {
    return UI->getUser();
  }

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

  operator user_iterator_impl<const UserTy>() const {
    return user_iterator_impl<const UserTy>(*UI);
  }

  Use &getUse() const { return *UI; }
};

215protected:
Value(Type *Ty, unsigned scid);

/// Value's destructor should be virtual by design, but that would require
/// that Value and all of its subclasses have a vtable that effectively
/// duplicates the information in the value ID. As a size optimization, the
/// destructor has been protected, and the caller should manually call
/// deleteValue.
~Value(); // Use deleteValue() to delete a generic Value.

225public:
Value(const Value &) = delete;
Value &operator=(const Value &) = delete;

/// Delete a pointer to a generic Value.
void deleteValue();

/// Support for debugging, callable in GDB: V->dump()
void dump() const;

/// Implement operator<< on Value.
/// @{
void print(raw_ostream &O, bool IsForDebug = false) const;
void print(raw_ostream &O, ModuleSlotTracker &MST,
           bool IsForDebug = false) const;
/// @}

/// Print the name of this Value out to the specified raw_ostream.
///
/// This is useful when you just want to print 'int %reg126', not the
/// instruction that generated it. If you specify a Module for context, then
/// even constanst get pretty-printed; for example, the type of a null
/// pointer is printed symbolically.
/// @{
void printAsOperand(raw_ostream &O, bool PrintType = true,
                    const Module *M = nullptr) const;
void printAsOperand(raw_ostream &O, bool PrintType,
                    ModuleSlotTracker &MST) const;
/// @}

/// All values are typed, get the type of this value.
Type *getType() const { return VTy; }

/// All values hold a context through their type.
LLVMContext &getContext() const;

// All values can potentially be named.
bool hasName() const { return HasName; }
ValueName *getValueName() const;
void setValueName(ValueName *VN);

266private:
void destroyValueName();
enum class ReplaceMetadataUses { No, Yes };
void doRAUW(Value *New, ReplaceMetadataUses);
void setNameImpl(const Twine &Name);

272public:
/// Return a constant reference to the value's name.
///
/// This guaranteed to return the same reference as long as the value is not
/// modified.  If the value has a name, this does a hashtable lookup, so it's
/// not free.
StringRef getName() const;

/// Change the name of the value.
///
/// Choose a new unique name if the provided name is taken.
///
/// \param Name The new name; or "" if the value's name should be removed.
void setName(const Twine &Name);

/// Transfer the name from V to this value.
///
/// After taking V's name, sets V's name to empty.
///
/// \note It is an error to call V->takeName(V).
void takeName(Value *V);

294#ifndef NDEBUG
std::string getNameOrAsOperand() const;
296#endif

/// Change all uses of this to point to a new Value.
///
/// Go through the uses list for this definition and make each use point to
/// "V" instead of "this".  After this completes, 'this's use list is
/// guaranteed to be empty.
void replaceAllUsesWith(Value *V);

/// Change non-metadata uses of this to point to a new Value.
///
/// Go through the uses list for this definition and make each use point to
/// "V" instead of "this". This function skips metadata entries in the list.
void replaceNonMetadataUsesWith(Value *V);

/// Go through the uses list for this definition and make each use point
/// to "V" if the callback ShouldReplace returns true for the given Use.
/// Unlike replaceAllUsesWith() this function does not support basic block
/// values.
void replaceUsesWithIf(Value *New,
                       llvm::function_ref<bool(Use &U)> ShouldReplace);

/// replaceUsesOutsideBlock - Go through the uses list for this definition and
/// make each use point to "V" instead of "this" when the use is outside the
/// block. 'This's use list is expected to have at least one element.
/// Unlike replaceAllUsesWith() this function does not support basic block
/// values.
void replaceUsesOutsideBlock(Value *V, BasicBlock *BB);

//----------------------------------------------------------------------
// Methods for handling the chain of uses of this Value.
//
// Materializing a function can introduce new uses, so these methods come in
// two variants:
// The methods that start with materialized_ check the uses that are
// currently known given which functions are materialized. Be very careful
// when using them since you might not get all uses.
// The methods that don't start with materialized_ assert that modules is
// fully materialized.
void assertModuleIsMaterializedImpl() const;
// This indirection exists so we can keep assertModuleIsMaterializedImpl()
// around in release builds of Value.cpp to be linked with other code built
// in debug mode. But this avoids calling it in any of the release built code.
void assertModuleIsMaterialized() const {
340#ifndef NDEBUG
  assertModuleIsMaterializedImpl();
342#endif
}

bool use_empty() const {
  assertModuleIsMaterialized();
  return UseList == nullptr;
16
←
Assuming the condition is false→
17
←
Returning zero, which participates in a condition later→
}

bool materialized_use_empty() const {
  return UseList == nullptr;
}

using use_iterator = use_iterator_impl<Use>;
using const_use_iterator = use_iterator_impl<const Use>;

use_iterator materialized_use_begin() { return use_iterator(UseList); }
const_use_iterator materialized_use_begin() const {
  return const_use_iterator(UseList);
}
use_iterator use_begin() {
  assertModuleIsMaterialized();
  return materialized_use_begin();
}
const_use_iterator use_begin() const {
  assertModuleIsMaterialized();
  return materialized_use_begin();
}
use_iterator use_end() { return use_iterator(); }
const_use_iterator use_end() const { return const_use_iterator(); }
iterator_range<use_iterator> materialized_uses() {
  return make_range(materialized_use_begin(), use_end());
}
iterator_range<const_use_iterator> materialized_uses() const {
  return make_range(materialized_use_begin(), use_end());
}
iterator_range<use_iterator> uses() {
  assertModuleIsMaterialized();
  return materialized_uses();
}
iterator_range<const_use_iterator> uses() const {
  assertModuleIsMaterialized();
  return materialized_uses();
}

bool user_empty() const {
  assertModuleIsMaterialized();
  return UseList == nullptr;
}

using user_iterator = user_iterator_impl<User>;
using const_user_iterator = user_iterator_impl<const User>;

user_iterator materialized_user_begin() { return user_iterator(UseList); }
const_user_iterator materialized_user_begin() const {
  return const_user_iterator(UseList);
}
user_iterator user_begin() {
  assertModuleIsMaterialized();
  return materialized_user_begin();
}
const_user_iterator user_begin() const {
  assertModuleIsMaterialized();
  return materialized_user_begin();
}
user_iterator user_end() { return user_iterator(); }
const_user_iterator user_end() const { return const_user_iterator(); }
User *user_back() {
  assertModuleIsMaterialized();
  return *materialized_user_begin();
}
const User *user_back() const {
  assertModuleIsMaterialized();
  return *materialized_user_begin();
}
iterator_range<user_iterator> materialized_users() {
  return make_range(materialized_user_begin(), user_end());
}
iterator_range<const_user_iterator> materialized_users() const {
  return make_range(materialized_user_begin(), user_end());
}
iterator_range<user_iterator> users() {
  assertModuleIsMaterialized();
  return materialized_users();
}
iterator_range<const_user_iterator> users() const {
  assertModuleIsMaterialized();
  return materialized_users();
}

/// Return true if there is exactly one use of this value.
///
/// This is specialized because it is a common request and does not require
/// traversing the whole use list.
bool hasOneUse() const { return hasSingleElement(uses()); }

/// Return true if this Value has exactly N uses.
bool hasNUses(unsigned N) const;

/// Return true if this value has N uses or more.
///
/// This is logically equivalent to getNumUses() >= N.
bool hasNUsesOrMore(unsigned N) const;

/// Return true if there is exactly one user of this value.
///
/// Note that this is not the same as "has one use". If a value has one use,
/// then there certainly is a single user. But if value has several uses,
/// it is possible that all uses are in a single user, or not.
///
/// This check is potentially costly, since it requires traversing,
/// in the worst case, the whole use list of a value.
bool hasOneUser() const;

/// Return true if there is exactly one use of this value that cannot be
/// dropped.
///
/// This is specialized because it is a common request and does not require
/// traversing the whole use list.
Use *getSingleUndroppableUse();
const Use *getSingleUndroppableUse() const {
  return const_cast<Value *>(this)->getSingleUndroppableUse();
}

/// Return true if there this value.
///
/// This is specialized because it is a common request and does not require
/// traversing the whole use list.
bool hasNUndroppableUses(unsigned N) const;

/// Return true if this value has N uses or more.
///
/// This is logically equivalent to getNumUses() >= N.
bool hasNUndroppableUsesOrMore(unsigned N) const;

/// Remove every uses that can safely be removed.
///
/// This will remove for example uses in llvm.assume.
/// This should be used when performing want to perform a tranformation but
/// some Droppable uses pervent it.
/// This function optionally takes a filter to only remove some droppable
/// uses.
void dropDroppableUses(llvm::function_ref<bool(const Use *)> ShouldDrop =
                           [](const Use *) { return true; });

/// Remove every use of this value in \p User that can safely be removed.
void dropDroppableUsesIn(User &Usr);

/// Remove the droppable use \p U.
static void dropDroppableUse(Use &U);

/// Check if this value is used in the specified basic block.
bool isUsedInBasicBlock(const BasicBlock *BB) const;

/// This method computes the number of uses of this Value.
///
/// This is a linear time operation.  Use hasOneUse, hasNUses, or
/// hasNUsesOrMore to check for specific values.
unsigned getNumUses() const;

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

/// Concrete subclass of this.
///
/// An enumeration for keeping track of the concrete subclass of Value that
/// is actually instantiated. Values of this enumeration are kept in the
/// Value classes SubclassID field. They are used for concrete type
/// identification.
enum ValueTy {
511#define HANDLE_VALUE(Name) Name##Val,
512#include "llvm/IR/Value.def"

  // Markers:
515#define HANDLE_CONSTANT_MARKER(Marker, Constant) Marker = Constant##Val,
516#include "llvm/IR/Value.def"
};

/// Return an ID for the concrete type of this object.
///
/// This is used to implement the classof checks.  This should not be used
/// for any other purpose, as the values may change as LLVM evolves.  Also,
/// note that for instructions, the Instruction's opcode is added to
/// InstructionVal. So this means three things:
/// # there is no value with code InstructionVal (no opcode==0).
/// # there are more possible values for the value type than in ValueTy enum.
/// # the InstructionVal enumerator must be the highest valued enumerator in
///   the ValueTy enum.
unsigned getValueID() const {
  return SubclassID;
}

/// Return the raw optional flags value contained in this value.
///
/// This should only be used when testing two Values for equivalence.
unsigned getRawSubclassOptionalData() const {
  return SubclassOptionalData;
}

/// Clear the optional flags contained in this value.
void clearSubclassOptionalData() {
  SubclassOptionalData = 0;
}

/// Check the optional flags for equality.
bool hasSameSubclassOptionalData(const Value *V) const {
  return SubclassOptionalData == V->SubclassOptionalData;
}

/// Return true if there is a value handle associated with this value.
bool hasValueHandle() const { return HasValueHandle; }

/// Return true if there is metadata referencing this value.
bool isUsedByMetadata() const { return IsUsedByMD; }

// Return true if this value is only transitively referenced by metadata.
bool isTransitiveUsedByMetadataOnly() const;

559protected:
/// Get the current metadata attachments for the given kind, if any.
///
/// These functions require that the value have at most a single attachment
/// of the given kind, and return \c nullptr if such an attachment is missing.
/// @{
MDNode *getMetadata(unsigned KindID) const;
MDNode *getMetadata(StringRef Kind) const;
/// @}

/// Appends all attachments with the given ID to \c MDs in insertion order.
/// If the Value has no attachments with the given ID, or if ID is invalid,
/// leaves MDs unchanged.
/// @{
void getMetadata(unsigned KindID, SmallVectorImpl<MDNode *> &MDs) const;
void getMetadata(StringRef Kind, SmallVectorImpl<MDNode *> &MDs) const;
/// @}

/// Appends all metadata attached to this value to \c MDs, sorting by
/// KindID. The first element of each pair returned is the KindID, the second
/// element is the metadata value. Attachments with the same ID appear in
/// insertion order.
void
getAllMetadata(SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const;

/// Return true if this value has any metadata attached to it.
bool hasMetadata() const { return (bool)HasMetadata; }

/// Return true if this value has the given type of metadata attached.
/// @{
bool hasMetadata(unsigned KindID) const {
  return getMetadata(KindID) != nullptr;
}
bool hasMetadata(StringRef Kind) const {
  return getMetadata(Kind) != nullptr;
}
/// @}

/// Set a particular kind of metadata attachment.
///
/// Sets the given attachment to \c MD, erasing it if \c MD is \c nullptr or
/// replacing it if it already exists.
/// @{
void setMetadata(unsigned KindID, MDNode *Node);
void setMetadata(StringRef Kind, MDNode *Node);
/// @}

/// Add a metadata attachment.
/// @{
void addMetadata(unsigned KindID, MDNode &MD);
void addMetadata(StringRef Kind, MDNode &MD);
/// @}

/// Erase all metadata attachments with the given kind.
///
/// \returns true if any metadata was removed.
bool eraseMetadata(unsigned KindID);

/// Erase all metadata attached to this Value.
void clearMetadata();

620public:
/// Return true if this value is a swifterror value.
///
/// swifterror values can be either a function argument or an alloca with a
/// swifterror attribute.
bool isSwiftError() const;

/// Strip off pointer casts, all-zero GEPs and address space casts.
///
/// Returns the original uncasted value.  If this is called on a non-pointer
/// value, it returns 'this'.
const Value *stripPointerCasts() const;
Value *stripPointerCasts() {
  return const_cast<Value *>(
      static_cast<const Value *>(this)->stripPointerCasts());
}

/// Strip off pointer casts, all-zero GEPs, address space casts, and aliases.
///
/// Returns the original uncasted value.  If this is called on a non-pointer
/// value, it returns 'this'.
const Value *stripPointerCastsAndAliases() const;
Value *stripPointerCastsAndAliases() {
  return const_cast<Value *>(
      static_cast<const Value *>(this)->stripPointerCastsAndAliases());
}

/// Strip off pointer casts, all-zero GEPs and address space casts
/// but ensures the representation of the result stays the same.
///
/// Returns the original uncasted value with the same representation. If this
/// is called on a non-pointer value, it returns 'this'.
const Value *stripPointerCastsSameRepresentation() const;
Value *stripPointerCastsSameRepresentation() {
  return const_cast<Value *>(static_cast<const Value *>(this)
                                 ->stripPointerCastsSameRepresentation());
}

/// Strip off pointer casts, all-zero GEPs, single-argument phi nodes and
/// invariant group info.
///
/// Returns the original uncasted value.  If this is called on a non-pointer
/// value, it returns 'this'. This function should be used only in
/// Alias analysis.
const Value *stripPointerCastsForAliasAnalysis() const;
Value *stripPointerCastsForAliasAnalysis() {
  return const_cast<Value *>(static_cast<const Value *>(this)
                                 ->stripPointerCastsForAliasAnalysis());
}

/// Strip off pointer casts and all-constant inbounds GEPs.
///
/// Returns the original pointer value.  If this is called on a non-pointer
/// value, it returns 'this'.
const Value *stripInBoundsConstantOffsets() const;
Value *stripInBoundsConstantOffsets() {
  return const_cast<Value *>(
            static_cast<const Value *>(this)->stripInBoundsConstantOffsets());
}

/// Accumulate the constant offset this value has compared to a base pointer.
/// Only 'getelementptr' instructions (GEPs) are accumulated but other
/// instructions, e.g., casts, are stripped away as well.
/// The accumulated constant offset is added to \p Offset and the base
/// pointer is returned.
///
/// The APInt \p Offset has to have a bit-width equal to the IntPtr type for
/// the address space of 'this' pointer value, e.g., use
/// DataLayout::getIndexTypeSizeInBits(Ty).
///
/// If \p AllowNonInbounds is true, offsets in GEPs are stripped and
/// accumulated even if the GEP is not "inbounds".
///
/// If \p ExternalAnalysis is provided it will be used to calculate a offset
/// when a operand of GEP is not constant.
/// For example, for a value \p ExternalAnalysis might try to calculate a
/// lower bound. If \p ExternalAnalysis is successful, it should return true.
///
/// If this is called on a non-pointer value, it returns 'this' and the
/// \p Offset is not modified.
///
/// Note that this function will never return a nullptr. It will also never
/// manipulate the \p Offset in a way that would not match the difference
/// between the underlying value and the returned one. Thus, if no constant
/// offset was found, the returned value is the underlying one and \p Offset
/// is unchanged.
const Value *stripAndAccumulateConstantOffsets(
    const DataLayout &DL, APInt &Offset, bool AllowNonInbounds,
    function_ref<bool(Value &Value, APInt &Offset)> ExternalAnalysis =
        nullptr) const;
Value *stripAndAccumulateConstantOffsets(const DataLayout &DL, APInt &Offset,
                                         bool AllowNonInbounds) {
  return const_cast<Value *>(
      static_cast<const Value *>(this)->stripAndAccumulateConstantOffsets(
          DL, Offset, AllowNonInbounds));
}

/// This is a wrapper around stripAndAccumulateConstantOffsets with the
/// in-bounds requirement set to false.
const Value *stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
                                                       APInt &Offset) const {
  return stripAndAccumulateConstantOffsets(DL, Offset,
                                           /* AllowNonInbounds */ false);
}
Value *stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
                                                 APInt &Offset) {
  return stripAndAccumulateConstantOffsets(DL, Offset,
                                           /* AllowNonInbounds */ false);
}

/// Strip off pointer casts and inbounds GEPs.
///
/// Returns the original pointer value.  If this is called on a non-pointer
/// value, it returns 'this'.
const Value *stripInBoundsOffsets(function_ref<void(const Value *)> Func =
                                      [](const Value *) {}) const;
inline Value *stripInBoundsOffsets(function_ref<void(const Value *)> Func =
                                [](const Value *) {}) {
  return const_cast<Value *>(
      static_cast<const Value *>(this)->stripInBoundsOffsets(Func));
}

/// Return true if the memory object referred to by V can by freed in the
/// scope for which the SSA value defining the allocation is statically
/// defined.  E.g.  deallocation after the static scope of a value does not
/// count, but a deallocation before that does.
bool canBeFreed() const;

/// Returns the number of bytes known to be dereferenceable for the
/// pointer value.
///
/// If CanBeNull is set by this function the pointer can either be null or be
/// dereferenceable up to the returned number of bytes.
///
/// IF CanBeFreed is true, the pointer is known to be dereferenceable at
/// point of definition only.  Caller must prove that allocation is not
/// deallocated between point of definition and use.
uint64_t getPointerDereferenceableBytes(const DataLayout &DL,
                                        bool &CanBeNull,
                                        bool &CanBeFreed) const;

/// Returns an alignment of the pointer value.
///
/// Returns an alignment which is either specified explicitly, e.g. via
/// align attribute of a function argument, or guaranteed by DataLayout.
Align getPointerAlignment(const DataLayout &DL) const;

/// Translate PHI node to its predecessor from the given basic block.
///
/// If this value is a PHI node with CurBB as its parent, return the value in
/// the PHI node corresponding to PredBB.  If not, return ourself.  This is
/// useful if you want to know the value something has in a predecessor
/// block.
const Value *DoPHITranslation(const BasicBlock *CurBB,
                              const BasicBlock *PredBB) const;
Value *DoPHITranslation(const BasicBlock *CurBB, const BasicBlock *PredBB) {
  return const_cast<Value *>(
           static_cast<const Value *>(this)->DoPHITranslation(CurBB, PredBB));
}

/// The maximum alignment for instructions.
///
/// This is the greatest alignment value supported by load, store, and alloca
/// instructions, and global values.
static constexpr unsigned MaxAlignmentExponent = 30;
static constexpr unsigned MaximumAlignment = 1u << MaxAlignmentExponent;

/// Mutate the type of this Value to be of the specified type.
///
/// Note that this is an extremely dangerous operation which can create
/// completely invalid IR very easily.  It is strongly recommended that you
/// recreate IR objects with the right types instead of mutating them in
/// place.
void mutateType(Type *Ty) {
  VTy = Ty;
}

/// Sort the use-list.
///
/// Sorts the Value's use-list by Cmp using a stable mergesort.  Cmp is
/// expected to compare two \a Use references.
template <class Compare> void sortUseList(Compare Cmp);

/// Reverse the use-list.
void reverseUseList();

806private:
/// Merge two lists together.
///
/// Merges \c L and \c R using \c Cmp.  To enable stable sorts, always pushes
/// "equal" items from L before items from R.
///
/// \return the first element in the list.
///
/// \note Completely ignores \a Use::Prev (doesn't read, doesn't update).
template <class Compare>
static Use *mergeUseLists(Use *L, Use *R, Compare Cmp) {
  Use *Merged;
  Use **Next = &Merged;

  while (true) {
    if (!L) {
      *Next = R;
      break;
    }
    if (!R) {
      *Next = L;
      break;
    }
    if (Cmp(*R, *L)) {
      *Next = R;
      Next = &R->Next;
      R = R->Next;
    } else {
      *Next = L;
      Next = &L->Next;
      L = L->Next;
    }
  }

  return Merged;
}

843protected:
unsigned short getSubclassDataFromValue() const { return SubclassData; }
void setValueSubclassData(unsigned short D) { SubclassData = D; }
846};

848struct ValueDeleter { void operator()(Value *V) { V->deleteValue(); } };

850/// Use this instead of std::unique_ptr<Value> or std::unique_ptr<Instruction>.
851/// Those don't work because Value and Instruction's destructors are protected,
852/// aren't virtual, and won't destroy the complete object.
853using unique_value = std::unique_ptr<Value, ValueDeleter>;

855inline raw_ostream &operator<<(raw_ostream &OS, const Value &V) {
V.print(OS);
return OS;
858}

860void Use::set(Value *V) {
if (Val) removeFromList();
Val = V;
if (V) V->addUse(*this);
864}

866Value *Use::operator=(Value *RHS) {
set(RHS);
return RHS;
869}

871const Use &Use::operator=(const Use &RHS) {
set(RHS.Val);
return *this;
874}

876template <class Compare> void Value::sortUseList(Compare Cmp) {
if (!UseList || !UseList->Next)
  // No need to sort 0 or 1 uses.
  return;

// Note: this function completely ignores Prev pointers until the end when
// they're fixed en masse.

// Create a binomial vector of sorted lists, visiting uses one at a time and
// merging lists as necessary.
const unsigned MaxSlots = 32;
Use *Slots[MaxSlots];

// Collect the first use, turning it into a single-item list.
Use *Next = UseList->Next;
UseList->Next = nullptr;
unsigned NumSlots = 1;
Slots[0] = UseList;

// Collect all but the last use.
while (Next->Next) {
  Use *Current = Next;
  Next = Current->Next;

  // Turn Current into a single-item list.
  Current->Next = nullptr;

  // Save Current in the first available slot, merging on collisions.
  unsigned I;
  for (I = 0; I < NumSlots; ++I) {
    if (!Slots[I])
      break;

    // Merge two lists, doubling the size of Current and emptying slot I.
    //
    // Since the uses in Slots[I] originally preceded those in Current, send
    // Slots[I] in as the left parameter to maintain a stable sort.
    Current = mergeUseLists(Slots[I], Current, Cmp);
    Slots[I] = nullptr;
  }
  // Check if this is a new slot.
  if (I == NumSlots) {
    ++NumSlots;
    assert(NumSlots <= MaxSlots && "Use list bigger than 2^32")(static_cast <bool> (NumSlots <= MaxSlots &&
 "Use list bigger than 2^32") ? void (0) : __assert_fail ("NumSlots <= MaxSlots && \"Use list bigger than 2^32\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/IR/Value.h"
, 919, __extension__ __PRETTY_FUNCTION__));
  }

  // Found an open slot.
  Slots[I] = Current;
}

// Merge all the lists together.
assert(Next && "Expected one more Use")(static_cast <bool> (Next && "Expected one more Use"
) ? void (0) : __assert_fail ("Next && \"Expected one more Use\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/IR/Value.h"
, 927, __extension__ __PRETTY_FUNCTION__));
assert(!Next->Next && "Expected only one Use")(static_cast <bool> (!Next->Next && "Expected only one Use"
) ? void (0) : __assert_fail ("!Next->Next && \"Expected only one Use\""
, "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/IR/Value.h"
, 928, __extension__ __PRETTY_FUNCTION__));
UseList = Next;
for (unsigned I = 0; I < NumSlots; ++I)
  if (Slots[I])
    // Since the uses in Slots[I] originally preceded those in UseList, send
    // Slots[I] in as the left parameter to maintain a stable sort.
    UseList = mergeUseLists(Slots[I], UseList, Cmp);

// Fix the Prev pointers.
for (Use *I = UseList, **Prev = &UseList; I; I = I->Next) {
  I->Prev = Prev;
  Prev = &I->Next;
}
941}

943// isa - Provide some specializations of isa so that we don't have to include
944// the subtype header files to test to see if the value is a subclass...
945//
946template <> struct isa_impl<Constant, Value> {
static inline bool doit(const Value &Val) {
  static_assert(Value::ConstantFirstVal == 0, "Val.getValueID() >= Value::ConstantFirstVal");
  return Val.getValueID() <= Value::ConstantLastVal;
}
951};

953template <> struct isa_impl<ConstantData, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() >= Value::ConstantDataFirstVal &&
         Val.getValueID() <= Value::ConstantDataLastVal;
}
958};

960template <> struct isa_impl<ConstantAggregate, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() >= Value::ConstantAggregateFirstVal &&
         Val.getValueID() <= Value::ConstantAggregateLastVal;
}
965};

967template <> struct isa_impl<Argument, Value> {
static inline bool doit (const Value &Val) {
  return Val.getValueID() == Value::ArgumentVal;
}
971};

973template <> struct isa_impl<InlineAsm, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() == Value::InlineAsmVal;
}
977};

979template <> struct isa_impl<Instruction, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() >= Value::InstructionVal;
}
983};

985template <> struct isa_impl<BasicBlock, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() == Value::BasicBlockVal;
}
989};

991template <> struct isa_impl<Function, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() == Value::FunctionVal;
}
995};

997template <> struct isa_impl<GlobalVariable, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() == Value::GlobalVariableVal;
}
1001};

1003template <> struct isa_impl<GlobalAlias, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() == Value::GlobalAliasVal;
}
1007};

1009template <> struct isa_impl<GlobalIFunc, Value> {
static inline bool doit(const Value &Val) {
  return Val.getValueID() == Value::GlobalIFuncVal;
}
1013};

1015template <> struct isa_impl<GlobalIndirectSymbol, Value> {
static inline bool doit(const Value &Val) {
  return isa<GlobalAlias>(Val) || isa<GlobalIFunc>(Val);
}
1019};

1021template <> struct isa_impl<GlobalValue, Value> {
static inline bool doit(const Value &Val) {
  return isa<GlobalObject>(Val) || isa<GlobalIndirectSymbol>(Val);
}
1025};

1027template <> struct isa_impl<GlobalObject, Value> {
static inline bool doit(const Value &Val) {
  return isa<GlobalVariable>(Val) || isa<Function>(Val);
}
1031};

1033// Create wrappers for C Binding types (see CBindingWrapping.h).
1034DEFINE_ISA_CONVERSION_FUNCTIONS(Value, LLVMValueRef)inline Value *unwrap(LLVMValueRef P) { return reinterpret_cast
<Value*>(P); } inline LLVMValueRef wrap(const Value *P)
 { return reinterpret_cast<LLVMValueRef>(const_cast<
Value*>(P)); } template<typename T> inline T *unwrap
(LLVMValueRef P) { return cast<T>(unwrap(P)); }

1036// Specialized opaque value conversions.
1037inline Value **unwrap(LLVMValueRef *Vals) {
return reinterpret_cast<Value**>(Vals);
1039}

1041template<typename T>
1042inline T **unwrap(LLVMValueRef *Vals, unsigned Length) {
1043#ifndef NDEBUG
for (LLVMValueRef *I = Vals, *E = Vals + Length; I != E; ++I)
  unwrap<T>(*I); // For side effect of calling assert on invalid usage.
1046#endif
(void)Length;
return reinterpret_cast<T**>(Vals);
1049}

1051inline LLVMValueRef *wrap(const Value **Vals) {
return reinterpret_cast<LLVMValueRef*>(const_cast<Value**>(Vals));
1053}

1055} // end namespace llvm

1057#endif // LLVM_IR_VALUE_H