/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

Bug Summary

File:	llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
Warning:	line 5364, column 42 Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name InstCombineCompares.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 -mthread-model posix -mframe-pointer=none -fmath-errno -fno-rounding-math -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/build-llvm/lib/Transforms/InstCombine -I /build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine -I /build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/build-llvm/include -I /build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/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-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/build-llvm/lib/Transforms/InstCombine -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2019-12-19-135931-35668-1 -x c++ /build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

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1//===- InstCombineCompares.cpp --------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the visitICmp and visitFCmp functions.
10//
11//===----------------------------------------------------------------------===//

13#include "InstCombineInternal.h"
14#include "llvm/ADT/APSInt.h"
15#include "llvm/ADT/SetVector.h"
16#include "llvm/ADT/Statistic.h"
17#include "llvm/Analysis/ConstantFolding.h"
18#include "llvm/Analysis/InstructionSimplify.h"
19#include "llvm/Analysis/TargetLibraryInfo.h"
20#include "llvm/IR/ConstantRange.h"
21#include "llvm/IR/DataLayout.h"
22#include "llvm/IR/GetElementPtrTypeIterator.h"
23#include "llvm/IR/IntrinsicInst.h"
24#include "llvm/IR/PatternMatch.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/KnownBits.h"

28using namespace llvm;
29using namespace PatternMatch;

31#define DEBUG_TYPE"instcombine" "instcombine"

33// How many times is a select replaced by one of its operands?
34STATISTIC(NumSel, "Number of select opts")static llvm::Statistic NumSel = {"instcombine", "NumSel", "Number of select opts"
};


37/// Compute Result = In1+In2, returning true if the result overflowed for this
38/// type.
39static bool addWithOverflow(APInt &Result, const APInt &In1,
                          const APInt &In2, bool IsSigned = false) {
bool Overflow;
if (IsSigned)
  Result = In1.sadd_ov(In2, Overflow);
else
  Result = In1.uadd_ov(In2, Overflow);

return Overflow;
48}

50/// Compute Result = In1-In2, returning true if the result overflowed for this
51/// type.
52static bool subWithOverflow(APInt &Result, const APInt &In1,
                          const APInt &In2, bool IsSigned = false) {
bool Overflow;
if (IsSigned)
  Result = In1.ssub_ov(In2, Overflow);
else
  Result = In1.usub_ov(In2, Overflow);

return Overflow;
61}

63/// Given an icmp instruction, return true if any use of this comparison is a
64/// branch on sign bit comparison.
65static bool hasBranchUse(ICmpInst &I) {
for (auto *U : I.users())
  if (isa<BranchInst>(U))
    return true;
return false;
70}

72/// Returns true if the exploded icmp can be expressed as a signed comparison
73/// to zero and updates the predicate accordingly.
74/// The signedness of the comparison is preserved.
75/// TODO: Refactor with decomposeBitTestICmp()?
76static bool isSignTest(ICmpInst::Predicate &Pred, const APInt &C) {
if (!ICmpInst::isSigned(Pred))
  return false;

if (C.isNullValue())
  return ICmpInst::isRelational(Pred);

if (C.isOneValue()) {
  if (Pred == ICmpInst::ICMP_SLT) {
    Pred = ICmpInst::ICMP_SLE;
    return true;
  }
} else if (C.isAllOnesValue()) {
  if (Pred == ICmpInst::ICMP_SGT) {
    Pred = ICmpInst::ICMP_SGE;
    return true;
  }
}

return false;
96}

98/// Given a signed integer type and a set of known zero and one bits, compute
99/// the maximum and minimum values that could have the specified known zero and
100/// known one bits, returning them in Min/Max.
101/// TODO: Move to method on KnownBits struct?
102static void computeSignedMinMaxValuesFromKnownBits(const KnownBits &Known,
                                                 APInt &Min, APInt &Max) {
assert(Known.getBitWidth() == Min.getBitWidth() &&((Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth
() == Max.getBitWidth() && "KnownZero, KnownOne and Min, Max must have equal bitwidth."
) ? static_cast<void> (0) : __assert_fail ("Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth() == Max.getBitWidth() && \"KnownZero, KnownOne and Min, Max must have equal bitwidth.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 106, __PRETTY_FUNCTION__))
       Known.getBitWidth() == Max.getBitWidth() &&((Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth
() == Max.getBitWidth() && "KnownZero, KnownOne and Min, Max must have equal bitwidth."
) ? static_cast<void> (0) : __assert_fail ("Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth() == Max.getBitWidth() && \"KnownZero, KnownOne and Min, Max must have equal bitwidth.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 106, __PRETTY_FUNCTION__))
       "KnownZero, KnownOne and Min, Max must have equal bitwidth.")((Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth
() == Max.getBitWidth() && "KnownZero, KnownOne and Min, Max must have equal bitwidth."
) ? static_cast<void> (0) : __assert_fail ("Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth() == Max.getBitWidth() && \"KnownZero, KnownOne and Min, Max must have equal bitwidth.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 106, __PRETTY_FUNCTION__));
APInt UnknownBits = ~(Known.Zero|Known.One);

// The minimum value is when all unknown bits are zeros, EXCEPT for the sign
// bit if it is unknown.
Min = Known.One;
Max = Known.One|UnknownBits;

if (UnknownBits.isNegative()) { // Sign bit is unknown
  Min.setSignBit();
  Max.clearSignBit();
}
118}

120/// Given an unsigned integer type and a set of known zero and one bits, compute
121/// the maximum and minimum values that could have the specified known zero and
122/// known one bits, returning them in Min/Max.
123/// TODO: Move to method on KnownBits struct?
124static void computeUnsignedMinMaxValuesFromKnownBits(const KnownBits &Known,
                                                   APInt &Min, APInt &Max) {
assert(Known.getBitWidth() == Min.getBitWidth() &&((Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth
() == Max.getBitWidth() && "Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth."
) ? static_cast<void> (0) : __assert_fail ("Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth() == Max.getBitWidth() && \"Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 128, __PRETTY_FUNCTION__))
       Known.getBitWidth() == Max.getBitWidth() &&((Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth
() == Max.getBitWidth() && "Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth."
) ? static_cast<void> (0) : __assert_fail ("Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth() == Max.getBitWidth() && \"Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 128, __PRETTY_FUNCTION__))
       "Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth.")((Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth
() == Max.getBitWidth() && "Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth."
) ? static_cast<void> (0) : __assert_fail ("Known.getBitWidth() == Min.getBitWidth() && Known.getBitWidth() == Max.getBitWidth() && \"Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 128, __PRETTY_FUNCTION__));
APInt UnknownBits = ~(Known.Zero|Known.One);

// The minimum value is when the unknown bits are all zeros.
Min = Known.One;
// The maximum value is when the unknown bits are all ones.
Max = Known.One|UnknownBits;
135}

137/// This is called when we see this pattern:
138///   cmp pred (load (gep GV, ...)), cmpcst
139/// where GV is a global variable with a constant initializer. Try to simplify
140/// this into some simple computation that does not need the load. For example
141/// we can optimize "icmp eq (load (gep "foo", 0, i)), 0" into "icmp eq i, 3".
142///
143/// If AndCst is non-null, then the loaded value is masked with that constant
144/// before doing the comparison. This handles cases like "A[i]&4 == 0".
145Instruction *InstCombiner::foldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
                                                      GlobalVariable *GV,
                                                      CmpInst &ICI,
                                                      ConstantInt *AndCst) {
Constant *Init = GV->getInitializer();
if (!isa<ConstantArray>(Init) && !isa<ConstantDataArray>(Init))
  return nullptr;

uint64_t ArrayElementCount = Init->getType()->getArrayNumElements();
// Don't blow up on huge arrays.
if (ArrayElementCount > MaxArraySizeForCombine)
  return nullptr;

// There are many forms of this optimization we can handle, for now, just do
// the simple index into a single-dimensional array.
//
// Require: GEP GV, 0, i {{, constant indices}}
if (GEP->getNumOperands() < 3 ||
    !isa<ConstantInt>(GEP->getOperand(1)) ||
    !cast<ConstantInt>(GEP->getOperand(1))->isZero() ||
    isa<Constant>(GEP->getOperand(2)))
  return nullptr;

// Check that indices after the variable are constants and in-range for the
// type they index.  Collect the indices.  This is typically for arrays of
// structs.
SmallVector<unsigned, 4> LaterIndices;

Type *EltTy = Init->getType()->getArrayElementType();
for (unsigned i = 3, e = GEP->getNumOperands(); i != e; ++i) {
  ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(i));
  if (!Idx) return nullptr;  // Variable index.

  uint64_t IdxVal = Idx->getZExtValue();
  if ((unsigned)IdxVal != IdxVal) return nullptr; // Too large array index.

  if (StructType *STy = dyn_cast<StructType>(EltTy))
    EltTy = STy->getElementType(IdxVal);
  else if (ArrayType *ATy = dyn_cast<ArrayType>(EltTy)) {
    if (IdxVal >= ATy->getNumElements()) return nullptr;
    EltTy = ATy->getElementType();
  } else {
    return nullptr; // Unknown type.
  }

  LaterIndices.push_back(IdxVal);
}

enum { Overdefined = -3, Undefined = -2 };

// Variables for our state machines.

// FirstTrueElement/SecondTrueElement - Used to emit a comparison of the form
// "i == 47 | i == 87", where 47 is the first index the condition is true for,
// and 87 is the second (and last) index.  FirstTrueElement is -2 when
// undefined, otherwise set to the first true element.  SecondTrueElement is
// -2 when undefined, -3 when overdefined and >= 0 when that index is true.
int FirstTrueElement = Undefined, SecondTrueElement = Undefined;

// FirstFalseElement/SecondFalseElement - Used to emit a comparison of the
// form "i != 47 & i != 87".  Same state transitions as for true elements.
int FirstFalseElement = Undefined, SecondFalseElement = Undefined;

/// TrueRangeEnd/FalseRangeEnd - In conjunction with First*Element, these
/// define a state machine that triggers for ranges of values that the index
/// is true or false for.  This triggers on things like "abbbbc"[i] == 'b'.
/// This is -2 when undefined, -3 when overdefined, and otherwise the last
/// index in the range (inclusive).  We use -2 for undefined here because we
/// use relative comparisons and don't want 0-1 to match -1.
int TrueRangeEnd = Undefined, FalseRangeEnd = Undefined;

// MagicBitvector - This is a magic bitvector where we set a bit if the
// comparison is true for element 'i'.  If there are 64 elements or less in
// the array, this will fully represent all the comparison results.
uint64_t MagicBitvector = 0;

// Scan the array and see if one of our patterns matches.
Constant *CompareRHS = cast<Constant>(ICI.getOperand(1));
for (unsigned i = 0, e = ArrayElementCount; i != e; ++i) {
  Constant *Elt = Init->getAggregateElement(i);
  if (!Elt) return nullptr;

  // If this is indexing an array of structures, get the structure element.
  if (!LaterIndices.empty())
    Elt = ConstantExpr::getExtractValue(Elt, LaterIndices);

  // If the element is masked, handle it.
  if (AndCst) Elt = ConstantExpr::getAnd(Elt, AndCst);

  // Find out if the comparison would be true or false for the i'th element.
  Constant *C = ConstantFoldCompareInstOperands(ICI.getPredicate(), Elt,
                                                CompareRHS, DL, &TLI);
  // If the result is undef for this element, ignore it.
  if (isa<UndefValue>(C)) {
    // Extend range state machines to cover this element in case there is an
    // undef in the middle of the range.
    if (TrueRangeEnd == (int)i-1)
      TrueRangeEnd = i;
    if (FalseRangeEnd == (int)i-1)
      FalseRangeEnd = i;
    continue;
  }

  // If we can't compute the result for any of the elements, we have to give
  // up evaluating the entire conditional.
  if (!isa<ConstantInt>(C)) return nullptr;

  // Otherwise, we know if the comparison is true or false for this element,
  // update our state machines.
  bool IsTrueForElt = !cast<ConstantInt>(C)->isZero();

  // State machine for single/double/range index comparison.
  if (IsTrueForElt) {
    // Update the TrueElement state machine.
    if (FirstTrueElement == Undefined)
      FirstTrueElement = TrueRangeEnd = i;  // First true element.
    else {
      // Update double-compare state machine.
      if (SecondTrueElement == Undefined)
        SecondTrueElement = i;
      else
        SecondTrueElement = Overdefined;

      // Update range state machine.
      if (TrueRangeEnd == (int)i-1)
        TrueRangeEnd = i;
      else
        TrueRangeEnd = Overdefined;
    }
  } else {
    // Update the FalseElement state machine.
    if (FirstFalseElement == Undefined)
      FirstFalseElement = FalseRangeEnd = i; // First false element.
    else {
      // Update double-compare state machine.
      if (SecondFalseElement == Undefined)
        SecondFalseElement = i;
      else
        SecondFalseElement = Overdefined;

      // Update range state machine.
      if (FalseRangeEnd == (int)i-1)
        FalseRangeEnd = i;
      else
        FalseRangeEnd = Overdefined;
    }
  }

  // If this element is in range, update our magic bitvector.
  if (i < 64 && IsTrueForElt)
    MagicBitvector |= 1ULL << i;

  // If all of our states become overdefined, bail out early.  Since the
  // predicate is expensive, only check it every 8 elements.  This is only
  // really useful for really huge arrays.
  if ((i & 8) == 0 && i >= 64 && SecondTrueElement == Overdefined &&
      SecondFalseElement == Overdefined && TrueRangeEnd == Overdefined &&
      FalseRangeEnd == Overdefined)
    return nullptr;
}

// Now that we've scanned the entire array, emit our new comparison(s).  We
// order the state machines in complexity of the generated code.
Value *Idx = GEP->getOperand(2);

// If the index is larger than the pointer size of the target, truncate the
// index down like the GEP would do implicitly.  We don't have to do this for
// an inbounds GEP because the index can't be out of range.
if (!GEP->isInBounds()) {
  Type *IntPtrTy = DL.getIntPtrType(GEP->getType());
  unsigned PtrSize = IntPtrTy->getIntegerBitWidth();
  if (Idx->getType()->getPrimitiveSizeInBits() > PtrSize)
    Idx = Builder.CreateTrunc(Idx, IntPtrTy);
}

// If the comparison is only true for one or two elements, emit direct
// comparisons.
if (SecondTrueElement != Overdefined) {
  // None true -> false.
  if (FirstTrueElement == Undefined)
    return replaceInstUsesWith(ICI, Builder.getFalse());

  Value *FirstTrueIdx = ConstantInt::get(Idx->getType(), FirstTrueElement);

  // True for one element -> 'i == 47'.
  if (SecondTrueElement == Undefined)
    return new ICmpInst(ICmpInst::ICMP_EQ, Idx, FirstTrueIdx);

  // True for two elements -> 'i == 47 | i == 72'.
  Value *C1 = Builder.CreateICmpEQ(Idx, FirstTrueIdx);
  Value *SecondTrueIdx = ConstantInt::get(Idx->getType(), SecondTrueElement);
  Value *C2 = Builder.CreateICmpEQ(Idx, SecondTrueIdx);
  return BinaryOperator::CreateOr(C1, C2);
}

// If the comparison is only false for one or two elements, emit direct
// comparisons.
if (SecondFalseElement != Overdefined) {
  // None false -> true.
  if (FirstFalseElement == Undefined)
    return replaceInstUsesWith(ICI, Builder.getTrue());

  Value *FirstFalseIdx = ConstantInt::get(Idx->getType(), FirstFalseElement);

  // False for one element -> 'i != 47'.
  if (SecondFalseElement == Undefined)
    return new ICmpInst(ICmpInst::ICMP_NE, Idx, FirstFalseIdx);

  // False for two elements -> 'i != 47 & i != 72'.
  Value *C1 = Builder.CreateICmpNE(Idx, FirstFalseIdx);
  Value *SecondFalseIdx = ConstantInt::get(Idx->getType(),SecondFalseElement);
  Value *C2 = Builder.CreateICmpNE(Idx, SecondFalseIdx);
  return BinaryOperator::CreateAnd(C1, C2);
}

// If the comparison can be replaced with a range comparison for the elements
// where it is true, emit the range check.
if (TrueRangeEnd != Overdefined) {
  assert(TrueRangeEnd != FirstTrueElement && "Should emit single compare")((TrueRangeEnd != FirstTrueElement && "Should emit single compare"
) ? static_cast<void> (0) : __assert_fail ("TrueRangeEnd != FirstTrueElement && \"Should emit single compare\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 363, __PRETTY_FUNCTION__));

  // Generate (i-FirstTrue) <u (TrueRangeEnd-FirstTrue+1).
  if (FirstTrueElement) {
    Value *Offs = ConstantInt::get(Idx->getType(), -FirstTrueElement);
    Idx = Builder.CreateAdd(Idx, Offs);
  }

  Value *End = ConstantInt::get(Idx->getType(),
                                TrueRangeEnd-FirstTrueElement+1);
  return new ICmpInst(ICmpInst::ICMP_ULT, Idx, End);
}

// False range check.
if (FalseRangeEnd != Overdefined) {
  assert(FalseRangeEnd != FirstFalseElement && "Should emit single compare")((FalseRangeEnd != FirstFalseElement && "Should emit single compare"
) ? static_cast<void> (0) : __assert_fail ("FalseRangeEnd != FirstFalseElement && \"Should emit single compare\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 378, __PRETTY_FUNCTION__));
  // Generate (i-FirstFalse) >u (FalseRangeEnd-FirstFalse).
  if (FirstFalseElement) {
    Value *Offs = ConstantInt::get(Idx->getType(), -FirstFalseElement);
    Idx = Builder.CreateAdd(Idx, Offs);
  }

  Value *End = ConstantInt::get(Idx->getType(),
                                FalseRangeEnd-FirstFalseElement);
  return new ICmpInst(ICmpInst::ICMP_UGT, Idx, End);
}

// If a magic bitvector captures the entire comparison state
// of this load, replace it with computation that does:
//   ((magic_cst >> i) & 1) != 0
{
  Type *Ty = nullptr;

  // Look for an appropriate type:
  // - The type of Idx if the magic fits
  // - The smallest fitting legal type
  if (ArrayElementCount <= Idx->getType()->getIntegerBitWidth())
    Ty = Idx->getType();
  else
    Ty = DL.getSmallestLegalIntType(Init->getContext(), ArrayElementCount);

  if (Ty) {
    Value *V = Builder.CreateIntCast(Idx, Ty, false);
    V = Builder.CreateLShr(ConstantInt::get(Ty, MagicBitvector), V);
    V = Builder.CreateAnd(ConstantInt::get(Ty, 1), V);
    return new ICmpInst(ICmpInst::ICMP_NE, V, ConstantInt::get(Ty, 0));
  }
}

return nullptr;
413}

415/// Return a value that can be used to compare the *offset* implied by a GEP to
416/// zero. For example, if we have &A[i], we want to return 'i' for
417/// "icmp ne i, 0". Note that, in general, indices can be complex, and scales
418/// are involved. The above expression would also be legal to codegen as
419/// "icmp ne (i*4), 0" (assuming A is a pointer to i32).
420/// This latter form is less amenable to optimization though, and we are allowed
421/// to generate the first by knowing that pointer arithmetic doesn't overflow.
422///
423/// If we can't emit an optimized form for this expression, this returns null.
424///
425static Value *evaluateGEPOffsetExpression(User *GEP, InstCombiner &IC,
                                        const DataLayout &DL) {
gep_type_iterator GTI = gep_type_begin(GEP);

// Check to see if this gep only has a single variable index.  If so, and if
// any constant indices are a multiple of its scale, then we can compute this
// in terms of the scale of the variable index.  For example, if the GEP
// implies an offset of "12 + i*4", then we can codegen this as "3 + i",
// because the expression will cross zero at the same point.
unsigned i, e = GEP->getNumOperands();
int64_t Offset = 0;
for (i = 1; i != e; ++i, ++GTI) {
  if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) {
    // Compute the aggregate offset of constant indices.
    if (CI->isZero()) continue;

    // Handle a struct index, which adds its field offset to the pointer.
    if (StructType *STy = GTI.getStructTypeOrNull()) {
      Offset += DL.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
    } else {
      uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
      Offset += Size*CI->getSExtValue();
    }
  } else {
    // Found our variable index.
    break;
  }
}

// If there are no variable indices, we must have a constant offset, just
// evaluate it the general way.
if (i == e) return nullptr;

Value *VariableIdx = GEP->getOperand(i);
// Determine the scale factor of the variable element.  For example, this is
// 4 if the variable index is into an array of i32.
uint64_t VariableScale = DL.getTypeAllocSize(GTI.getIndexedType());

// Verify that there are no other variable indices.  If so, emit the hard way.
for (++i, ++GTI; i != e; ++i, ++GTI) {
  ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i));
  if (!CI) return nullptr;

  // Compute the aggregate offset of constant indices.
  if (CI->isZero()) continue;

  // Handle a struct index, which adds its field offset to the pointer.
  if (StructType *STy = GTI.getStructTypeOrNull()) {
    Offset += DL.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
  } else {
    uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
    Offset += Size*CI->getSExtValue();
  }
}

// Okay, we know we have a single variable index, which must be a
// pointer/array/vector index.  If there is no offset, life is simple, return
// the index.
Type *IntPtrTy = DL.getIntPtrType(GEP->getOperand(0)->getType());
unsigned IntPtrWidth = IntPtrTy->getIntegerBitWidth();
if (Offset == 0) {
  // Cast to intptrty in case a truncation occurs.  If an extension is needed,
  // we don't need to bother extending: the extension won't affect where the
  // computation crosses zero.
  if (VariableIdx->getType()->getPrimitiveSizeInBits() > IntPtrWidth) {
    VariableIdx = IC.Builder.CreateTrunc(VariableIdx, IntPtrTy);
  }
  return VariableIdx;
}

// Otherwise, there is an index.  The computation we will do will be modulo
// the pointer size.
Offset = SignExtend64(Offset, IntPtrWidth);
VariableScale = SignExtend64(VariableScale, IntPtrWidth);

// To do this transformation, any constant index must be a multiple of the
// variable scale factor.  For example, we can evaluate "12 + 4*i" as "3 + i",
// but we can't evaluate "10 + 3*i" in terms of i.  Check that the offset is a
// multiple of the variable scale.
int64_t NewOffs = Offset / (int64_t)VariableScale;
if (Offset != NewOffs*(int64_t)VariableScale)
  return nullptr;

// Okay, we can do this evaluation.  Start by converting the index to intptr.
if (VariableIdx->getType() != IntPtrTy)
  VariableIdx = IC.Builder.CreateIntCast(VariableIdx, IntPtrTy,
                                          true /*Signed*/);
Constant *OffsetVal = ConstantInt::get(IntPtrTy, NewOffs);
return IC.Builder.CreateAdd(VariableIdx, OffsetVal, "offset");
514}

516/// Returns true if we can rewrite Start as a GEP with pointer Base
517/// and some integer offset. The nodes that need to be re-written
518/// for this transformation will be added to Explored.
519static bool canRewriteGEPAsOffset(Value *Start, Value *Base,
                                const DataLayout &DL,
                                SetVector<Value *> &Explored) {
SmallVector<Value *, 16> WorkList(1, Start);
Explored.insert(Base);

// The following traversal gives us an order which can be used
// when doing the final transformation. Since in the final
// transformation we create the PHI replacement instructions first,
// we don't have to get them in any particular order.
//
// However, for other instructions we will have to traverse the
// operands of an instruction first, which means that we have to
// do a post-order traversal.
while (!WorkList.empty()) {
  SetVector<PHINode *> PHIs;

  while (!WorkList.empty()) {
    if (Explored.size() >= 100)
      return false;

    Value *V = WorkList.back();

    if (Explored.count(V) != 0) {
      WorkList.pop_back();
      continue;
    }

    if (!isa<IntToPtrInst>(V) && !isa<PtrToIntInst>(V) &&
        !isa<GetElementPtrInst>(V) && !isa<PHINode>(V))
      // We've found some value that we can't explore which is different from
      // the base. Therefore we can't do this transformation.
      return false;

    if (isa<IntToPtrInst>(V) || isa<PtrToIntInst>(V)) {
      auto *CI = dyn_cast<CastInst>(V);
      if (!CI->isNoopCast(DL))
        return false;

      if (Explored.count(CI->getOperand(0)) == 0)
        WorkList.push_back(CI->getOperand(0));
    }

    if (auto *GEP = dyn_cast<GEPOperator>(V)) {
      // We're limiting the GEP to having one index. This will preserve
      // the original pointer type. We could handle more cases in the
      // future.
      if (GEP->getNumIndices() != 1 || !GEP->isInBounds() ||
          GEP->getType() != Start->getType())
        return false;

      if (Explored.count(GEP->getOperand(0)) == 0)
        WorkList.push_back(GEP->getOperand(0));
    }

    if (WorkList.back() == V) {
      WorkList.pop_back();
      // We've finished visiting this node, mark it as such.
      Explored.insert(V);
    }

    if (auto *PN = dyn_cast<PHINode>(V)) {
      // We cannot transform PHIs on unsplittable basic blocks.
      if (isa<CatchSwitchInst>(PN->getParent()->getTerminator()))
        return false;
      Explored.insert(PN);
      PHIs.insert(PN);
    }
  }

  // Explore the PHI nodes further.
  for (auto *PN : PHIs)
    for (Value *Op : PN->incoming_values())
      if (Explored.count(Op) == 0)
        WorkList.push_back(Op);
}

// Make sure that we can do this. Since we can't insert GEPs in a basic
// block before a PHI node, we can't easily do this transformation if
// we have PHI node users of transformed instructions.
for (Value *Val : Explored) {
  for (Value *Use : Val->uses()) {

    auto *PHI = dyn_cast<PHINode>(Use);
    auto *Inst = dyn_cast<Instruction>(Val);

    if (Inst == Base || Inst == PHI || !Inst || !PHI ||
        Explored.count(PHI) == 0)
      continue;

    if (PHI->getParent() == Inst->getParent())
      return false;
  }
}
return true;
614}

616// Sets the appropriate insert point on Builder where we can add
617// a replacement Instruction for V (if that is possible).
618static void setInsertionPoint(IRBuilder<> &Builder, Value *V,
                            bool Before = true) {
if (auto *PHI = dyn_cast<PHINode>(V)) {
  Builder.SetInsertPoint(&*PHI->getParent()->getFirstInsertionPt());
  return;
}
if (auto *I = dyn_cast<Instruction>(V)) {
  if (!Before)
    I = &*std::next(I->getIterator());
  Builder.SetInsertPoint(I);
  return;
}
if (auto *A = dyn_cast<Argument>(V)) {
  // Set the insertion point in the entry block.
  BasicBlock &Entry = A->getParent()->getEntryBlock();
  Builder.SetInsertPoint(&*Entry.getFirstInsertionPt());
  return;
}
// Otherwise, this is a constant and we don't need to set a new
// insertion point.
assert(isa<Constant>(V) && "Setting insertion point for unknown value!")((isa<Constant>(V) && "Setting insertion point for unknown value!"
) ? static_cast<void> (0) : __assert_fail ("isa<Constant>(V) && \"Setting insertion point for unknown value!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 638, __PRETTY_FUNCTION__));
639}

641/// Returns a re-written value of Start as an indexed GEP using Base as a
642/// pointer.
643static Value *rewriteGEPAsOffset(Value *Start, Value *Base,
                               const DataLayout &DL,
                               SetVector<Value *> &Explored) {
// Perform all the substitutions. This is a bit tricky because we can
// have cycles in our use-def chains.
// 1. Create the PHI nodes without any incoming values.
// 2. Create all the other values.
// 3. Add the edges for the PHI nodes.
// 4. Emit GEPs to get the original pointers.
// 5. Remove the original instructions.
Type *IndexType = IntegerType::get(
    Base->getContext(), DL.getIndexTypeSizeInBits(Start->getType()));

DenseMap<Value *, Value *> NewInsts;
NewInsts[Base] = ConstantInt::getNullValue(IndexType);

// Create the new PHI nodes, without adding any incoming values.
for (Value *Val : Explored) {
  if (Val == Base)
    continue;
  // Create empty phi nodes. This avoids cyclic dependencies when creating
  // the remaining instructions.
  if (auto *PHI = dyn_cast<PHINode>(Val))
    NewInsts[PHI] = PHINode::Create(IndexType, PHI->getNumIncomingValues(),
                                    PHI->getName() + ".idx", PHI);
}
IRBuilder<> Builder(Base->getContext());

// Create all the other instructions.
for (Value *Val : Explored) {

  if (NewInsts.find(Val) != NewInsts.end())
    continue;

  if (auto *CI = dyn_cast<CastInst>(Val)) {
    // Don't get rid of the intermediate variable here; the store can grow
    // the map which will invalidate the reference to the input value.
    Value *V = NewInsts[CI->getOperand(0)];
    NewInsts[CI] = V;
    continue;
  }
  if (auto *GEP = dyn_cast<GEPOperator>(Val)) {
    Value *Index = NewInsts[GEP->getOperand(1)] ? NewInsts[GEP->getOperand(1)]
                                                : GEP->getOperand(1);
    setInsertionPoint(Builder, GEP);
    // Indices might need to be sign extended. GEPs will magically do
    // this, but we need to do it ourselves here.
    if (Index->getType()->getScalarSizeInBits() !=
        NewInsts[GEP->getOperand(0)]->getType()->getScalarSizeInBits()) {
      Index = Builder.CreateSExtOrTrunc(
          Index, NewInsts[GEP->getOperand(0)]->getType(),
          GEP->getOperand(0)->getName() + ".sext");
    }

    auto *Op = NewInsts[GEP->getOperand(0)];
    if (isa<ConstantInt>(Op) && cast<ConstantInt>(Op)->isZero())
      NewInsts[GEP] = Index;
    else
      NewInsts[GEP] = Builder.CreateNSWAdd(
          Op, Index, GEP->getOperand(0)->getName() + ".add");
    continue;
  }
  if (isa<PHINode>(Val))
    continue;

  llvm_unreachable("Unexpected instruction type")::llvm::llvm_unreachable_internal("Unexpected instruction type"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 708);
}

// Add the incoming values to the PHI nodes.
for (Value *Val : Explored) {
  if (Val == Base)
    continue;
  // All the instructions have been created, we can now add edges to the
  // phi nodes.
  if (auto *PHI = dyn_cast<PHINode>(Val)) {
    PHINode *NewPhi = static_cast<PHINode *>(NewInsts[PHI]);
    for (unsigned I = 0, E = PHI->getNumIncomingValues(); I < E; ++I) {
      Value *NewIncoming = PHI->getIncomingValue(I);

      if (NewInsts.find(NewIncoming) != NewInsts.end())
        NewIncoming = NewInsts[NewIncoming];

      NewPhi->addIncoming(NewIncoming, PHI->getIncomingBlock(I));
    }
  }
}

for (Value *Val : Explored) {
  if (Val == Base)
    continue;

  // Depending on the type, for external users we have to emit
  // a GEP or a GEP + ptrtoint.
  setInsertionPoint(Builder, Val, false);

  // If required, create an inttoptr instruction for Base.
  Value *NewBase = Base;
  if (!Base->getType()->isPointerTy())
    NewBase = Builder.CreateBitOrPointerCast(Base, Start->getType(),
                                             Start->getName() + "to.ptr");

  Value *GEP = Builder.CreateInBoundsGEP(
      Start->getType()->getPointerElementType(), NewBase,
      makeArrayRef(NewInsts[Val]), Val->getName() + ".ptr");

  if (!Val->getType()->isPointerTy()) {
    Value *Cast = Builder.CreatePointerCast(GEP, Val->getType(),
                                            Val->getName() + ".conv");
    GEP = Cast;
  }
  Val->replaceAllUsesWith(GEP);
}

return NewInsts[Start];
757}

759/// Looks through GEPs, IntToPtrInsts and PtrToIntInsts in order to express
760/// the input Value as a constant indexed GEP. Returns a pair containing
761/// the GEPs Pointer and Index.
762static std::pair<Value *, Value *>
763getAsConstantIndexedAddress(Value *V, const DataLayout &DL) {
Type *IndexType = IntegerType::get(V->getContext(),
                                   DL.getIndexTypeSizeInBits(V->getType()));

Constant *Index = ConstantInt::getNullValue(IndexType);
while (true) {
  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
    // We accept only inbouds GEPs here to exclude the possibility of
    // overflow.
    if (!GEP->isInBounds())
      break;
    if (GEP->hasAllConstantIndices() && GEP->getNumIndices() == 1 &&
        GEP->getType() == V->getType()) {
      V = GEP->getOperand(0);
      Constant *GEPIndex = static_cast<Constant *>(GEP->getOperand(1));
      Index = ConstantExpr::getAdd(
          Index, ConstantExpr::getSExtOrBitCast(GEPIndex, IndexType));
      continue;
    }
    break;
  }
  if (auto *CI = dyn_cast<IntToPtrInst>(V)) {
    if (!CI->isNoopCast(DL))
      break;
    V = CI->getOperand(0);
    continue;
  }
  if (auto *CI = dyn_cast<PtrToIntInst>(V)) {
    if (!CI->isNoopCast(DL))
      break;
    V = CI->getOperand(0);
    continue;
  }
  break;
}
return {V, Index};
799}

801/// Converts (CMP GEPLHS, RHS) if this change would make RHS a constant.
802/// We can look through PHIs, GEPs and casts in order to determine a common base
803/// between GEPLHS and RHS.
804static Instruction *transformToIndexedCompare(GEPOperator *GEPLHS, Value *RHS,
                                            ICmpInst::Predicate Cond,
                                            const DataLayout &DL) {
// FIXME: Support vector of pointers.
if (GEPLHS->getType()->isVectorTy())
  return nullptr;

if (!GEPLHS->hasAllConstantIndices())
  return nullptr;

// Make sure the pointers have the same type.
if (GEPLHS->getType() != RHS->getType())
  return nullptr;

Value *PtrBase, *Index;
std::tie(PtrBase, Index) = getAsConstantIndexedAddress(GEPLHS, DL);

// The set of nodes that will take part in this transformation.
SetVector<Value *> Nodes;

if (!canRewriteGEPAsOffset(RHS, PtrBase, DL, Nodes))
  return nullptr;

// We know we can re-write this as
//  ((gep Ptr, OFFSET1) cmp (gep Ptr, OFFSET2)
// Since we've only looked through inbouds GEPs we know that we
// can't have overflow on either side. We can therefore re-write
// this as:
//   OFFSET1 cmp OFFSET2
Value *NewRHS = rewriteGEPAsOffset(RHS, PtrBase, DL, Nodes);

// RewriteGEPAsOffset has replaced RHS and all of its uses with a re-written
// GEP having PtrBase as the pointer base, and has returned in NewRHS the
// offset. Since Index is the offset of LHS to the base pointer, we will now
// compare the offsets instead of comparing the pointers.
return new ICmpInst(ICmpInst::getSignedPredicate(Cond), Index, NewRHS);
840}

842/// Fold comparisons between a GEP instruction and something else. At this point
843/// we know that the GEP is on the LHS of the comparison.
844Instruction *InstCombiner::foldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
                                     ICmpInst::Predicate Cond,
                                     Instruction &I) {
// Don't transform signed compares of GEPs into index compares. Even if the
// GEP is inbounds, the final add of the base pointer can have signed overflow
// and would change the result of the icmp.
// e.g. "&foo[0] <s &foo[1]" can't be folded to "true" because "foo" could be
// the maximum signed value for the pointer type.
if (ICmpInst::isSigned(Cond))
  return nullptr;

// Look through bitcasts and addrspacecasts. We do not however want to remove
// 0 GEPs.
if (!isa<GetElementPtrInst>(RHS))
  RHS = RHS->stripPointerCasts();

Value *PtrBase = GEPLHS->getOperand(0);
// FIXME: Support vector pointer GEPs.
if (PtrBase == RHS && GEPLHS->isInBounds() &&
    !GEPLHS->getType()->isVectorTy()) {
  // ((gep Ptr, OFFSET) cmp Ptr)   ---> (OFFSET cmp 0).
  // This transformation (ignoring the base and scales) is valid because we
  // know pointers can't overflow since the gep is inbounds.  See if we can
  // output an optimized form.
  Value *Offset = evaluateGEPOffsetExpression(GEPLHS, *this, DL);

  // If not, synthesize the offset the hard way.
  if (!Offset)
    Offset = EmitGEPOffset(GEPLHS);
  return new ICmpInst(ICmpInst::getSignedPredicate(Cond), Offset,
                      Constant::getNullValue(Offset->getType()));
}

if (GEPLHS->isInBounds() && ICmpInst::isEquality(Cond) &&
    isa<Constant>(RHS) && cast<Constant>(RHS)->isNullValue() &&
    !NullPointerIsDefined(I.getFunction(),
                          RHS->getType()->getPointerAddressSpace())) {
  // For most address spaces, an allocation can't be placed at null, but null
  // itself is treated as a 0 size allocation in the in bounds rules.  Thus,
  // the only valid inbounds address derived from null, is null itself.
  // Thus, we have four cases to consider:
  // 1) Base == nullptr, Offset == 0 -> inbounds, null
  // 2) Base == nullptr, Offset != 0 -> poison as the result is out of bounds
  // 3) Base != nullptr, Offset == (-base) -> poison (crossing allocations)
  // 4) Base != nullptr, Offset != (-base) -> nonnull (and possibly poison)
  //
  // (Note if we're indexing a type of size 0, that simply collapses into one
  //  of the buckets above.)
  //
  // In general, we're allowed to make values less poison (i.e. remove
  //   sources of full UB), so in this case, we just select between the two
  //   non-poison cases (1 and 4 above).
  //
  // For vectors, we apply the same reasoning on a per-lane basis.
  auto *Base = GEPLHS->getPointerOperand();
  if (GEPLHS->getType()->isVectorTy() && Base->getType()->isPointerTy()) {
    int NumElts = GEPLHS->getType()->getVectorNumElements();
    Base = Builder.CreateVectorSplat(NumElts, Base);
  }
  return new ICmpInst(Cond, Base,
                      ConstantExpr::getPointerBitCastOrAddrSpaceCast(
                          cast<Constant>(RHS), Base->getType()));
} else if (GEPOperator *GEPRHS = dyn_cast<GEPOperator>(RHS)) {
  // If the base pointers are different, but the indices are the same, just
  // compare the base pointer.
  if (PtrBase != GEPRHS->getOperand(0)) {
    bool IndicesTheSame = GEPLHS->getNumOperands()==GEPRHS->getNumOperands();
    IndicesTheSame &= GEPLHS->getOperand(0)->getType() ==
                      GEPRHS->getOperand(0)->getType();
    if (IndicesTheSame)
      for (unsigned i = 1, e = GEPLHS->getNumOperands(); i != e; ++i)
        if (GEPLHS->getOperand(i) != GEPRHS->getOperand(i)) {
          IndicesTheSame = false;
          break;
        }

    // If all indices are the same, just compare the base pointers.
    Type *BaseType = GEPLHS->getOperand(0)->getType();
    if (IndicesTheSame && CmpInst::makeCmpResultType(BaseType) == I.getType())
      return new ICmpInst(Cond, GEPLHS->getOperand(0), GEPRHS->getOperand(0));

    // If we're comparing GEPs with two base pointers that only differ in type
    // and both GEPs have only constant indices or just one use, then fold
    // the compare with the adjusted indices.
    // FIXME: Support vector of pointers.
    if (GEPLHS->isInBounds() && GEPRHS->isInBounds() &&
        (GEPLHS->hasAllConstantIndices() || GEPLHS->hasOneUse()) &&
        (GEPRHS->hasAllConstantIndices() || GEPRHS->hasOneUse()) &&
        PtrBase->stripPointerCasts() ==
            GEPRHS->getOperand(0)->stripPointerCasts() &&
        !GEPLHS->getType()->isVectorTy()) {
      Value *LOffset = EmitGEPOffset(GEPLHS);
      Value *ROffset = EmitGEPOffset(GEPRHS);

      // If we looked through an addrspacecast between different sized address
      // spaces, the LHS and RHS pointers are different sized
      // integers. Truncate to the smaller one.
      Type *LHSIndexTy = LOffset->getType();
      Type *RHSIndexTy = ROffset->getType();
      if (LHSIndexTy != RHSIndexTy) {
        if (LHSIndexTy->getPrimitiveSizeInBits() <
            RHSIndexTy->getPrimitiveSizeInBits()) {
          ROffset = Builder.CreateTrunc(ROffset, LHSIndexTy);
        } else
          LOffset = Builder.CreateTrunc(LOffset, RHSIndexTy);
      }

      Value *Cmp = Builder.CreateICmp(ICmpInst::getSignedPredicate(Cond),
                                      LOffset, ROffset);
      return replaceInstUsesWith(I, Cmp);
    }

    // Otherwise, the base pointers are different and the indices are
    // different. Try convert this to an indexed compare by looking through
    // PHIs/casts.
    return transformToIndexedCompare(GEPLHS, RHS, Cond, DL);
  }

  // If one of the GEPs has all zero indices, recurse.
  // FIXME: Handle vector of pointers.
  if (!GEPLHS->getType()->isVectorTy() && GEPLHS->hasAllZeroIndices())
    return foldGEPICmp(GEPRHS, GEPLHS->getOperand(0),
                       ICmpInst::getSwappedPredicate(Cond), I);

  // If the other GEP has all zero indices, recurse.
  // FIXME: Handle vector of pointers.
  if (!GEPRHS->getType()->isVectorTy() && GEPRHS->hasAllZeroIndices())
    return foldGEPICmp(GEPLHS, GEPRHS->getOperand(0), Cond, I);

  bool GEPsInBounds = GEPLHS->isInBounds() && GEPRHS->isInBounds();
  if (GEPLHS->getNumOperands() == GEPRHS->getNumOperands()) {
    // If the GEPs only differ by one index, compare it.
    unsigned NumDifferences = 0;  // Keep track of # differences.
    unsigned DiffOperand = 0;     // The operand that differs.
    for (unsigned i = 1, e = GEPRHS->getNumOperands(); i != e; ++i)
      if (GEPLHS->getOperand(i) != GEPRHS->getOperand(i)) {
        Type *LHSType = GEPLHS->getOperand(i)->getType();
        Type *RHSType = GEPRHS->getOperand(i)->getType();
        // FIXME: Better support for vector of pointers.
        if (LHSType->getPrimitiveSizeInBits() !=
                 RHSType->getPrimitiveSizeInBits() ||
            (GEPLHS->getType()->isVectorTy() &&
             (!LHSType->isVectorTy() || !RHSType->isVectorTy()))) {
          // Irreconcilable differences.
          NumDifferences = 2;
          break;
        }

        if (NumDifferences++) break;
        DiffOperand = i;
      }

    if (NumDifferences == 0)   // SAME GEP?
      return replaceInstUsesWith(I, // No comparison is needed here.
        ConstantInt::get(I.getType(), ICmpInst::isTrueWhenEqual(Cond)));

    else if (NumDifferences == 1 && GEPsInBounds) {
      Value *LHSV = GEPLHS->getOperand(DiffOperand);
      Value *RHSV = GEPRHS->getOperand(DiffOperand);
      // Make sure we do a signed comparison here.
      return new ICmpInst(ICmpInst::getSignedPredicate(Cond), LHSV, RHSV);
    }
  }

  // Only lower this if the icmp is the only user of the GEP or if we expect
  // the result to fold to a constant!
  if (GEPsInBounds && (isa<ConstantExpr>(GEPLHS) || GEPLHS->hasOneUse()) &&
      (isa<ConstantExpr>(GEPRHS) || GEPRHS->hasOneUse())) {
    // ((gep Ptr, OFFSET1) cmp (gep Ptr, OFFSET2)  --->  (OFFSET1 cmp OFFSET2)
    Value *L = EmitGEPOffset(GEPLHS);
    Value *R = EmitGEPOffset(GEPRHS);
    return new ICmpInst(ICmpInst::getSignedPredicate(Cond), L, R);
  }
}

// Try convert this to an indexed compare by looking through PHIs/casts as a
// last resort.
return transformToIndexedCompare(GEPLHS, RHS, Cond, DL);
1022}

1024Instruction *InstCombiner::foldAllocaCmp(ICmpInst &ICI,
                                       const AllocaInst *Alloca,
                                       const Value *Other) {
assert(ICI.isEquality() && "Cannot fold non-equality comparison.")((ICI.isEquality() && "Cannot fold non-equality comparison."
) ? static_cast<void> (0) : __assert_fail ("ICI.isEquality() && \"Cannot fold non-equality comparison.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1027, __PRETTY_FUNCTION__));

// It would be tempting to fold away comparisons between allocas and any
// pointer not based on that alloca (e.g. an argument). However, even
// though such pointers cannot alias, they can still compare equal.
//
// But LLVM doesn't specify where allocas get their memory, so if the alloca
// doesn't escape we can argue that it's impossible to guess its value, and we
// can therefore act as if any such guesses are wrong.
//
// The code below checks that the alloca doesn't escape, and that it's only
// used in a comparison once (the current instruction). The
// single-comparison-use condition ensures that we're trivially folding all
// comparisons against the alloca consistently, and avoids the risk of
// erroneously folding a comparison of the pointer with itself.

unsigned MaxIter = 32; // Break cycles and bound to constant-time.

SmallVector<const Use *, 32> Worklist;
for (const Use &U : Alloca->uses()) {
  if (Worklist.size() >= MaxIter)
    return nullptr;
  Worklist.push_back(&U);
}

unsigned NumCmps = 0;
while (!Worklist.empty()) {
  assert(Worklist.size() <= MaxIter)((Worklist.size() <= MaxIter) ? static_cast<void> (0
) : __assert_fail ("Worklist.size() <= MaxIter", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1054, __PRETTY_FUNCTION__));
  const Use *U = Worklist.pop_back_val();
  const Value *V = U->getUser();
  --MaxIter;

  if (isa<BitCastInst>(V) || isa<GetElementPtrInst>(V) || isa<PHINode>(V) ||
      isa<SelectInst>(V)) {
    // Track the uses.
  } else if (isa<LoadInst>(V)) {
    // Loading from the pointer doesn't escape it.
    continue;
  } else if (const auto *SI = dyn_cast<StoreInst>(V)) {
    // Storing *to* the pointer is fine, but storing the pointer escapes it.
    if (SI->getValueOperand() == U->get())
      return nullptr;
    continue;
  } else if (isa<ICmpInst>(V)) {
    if (NumCmps++)
      return nullptr; // Found more than one cmp.
    continue;
  } else if (const auto *Intrin = dyn_cast<IntrinsicInst>(V)) {
    switch (Intrin->getIntrinsicID()) {
      // These intrinsics don't escape or compare the pointer. Memset is safe
      // because we don't allow ptrtoint. Memcpy and memmove are safe because
      // we don't allow stores, so src cannot point to V.
      case Intrinsic::lifetime_start: case Intrinsic::lifetime_end:
      case Intrinsic::memcpy: case Intrinsic::memmove: case Intrinsic::memset:
        continue;
      default:
        return nullptr;
    }
  } else {
    return nullptr;
  }
  for (const Use &U : V->uses()) {
    if (Worklist.size() >= MaxIter)
      return nullptr;
    Worklist.push_back(&U);
  }
}

Type *CmpTy = CmpInst::makeCmpResultType(Other->getType());
return replaceInstUsesWith(
    ICI,
    ConstantInt::get(CmpTy, !CmpInst::isTrueWhenEqual(ICI.getPredicate())));
1099}

1101/// Fold "icmp pred (X+C), X".
1102Instruction *InstCombiner::foldICmpAddOpConst(Value *X, const APInt &C,
                                            ICmpInst::Predicate Pred) {
// From this point on, we know that (X+C <= X) --> (X+C < X) because C != 0,
// so the values can never be equal.  Similarly for all other "or equals"
// operators.
assert(!!C && "C should not be zero!")((!!C && "C should not be zero!") ? static_cast<void
> (0) : __assert_fail ("!!C && \"C should not be zero!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1107, __PRETTY_FUNCTION__));

// (X+1) <u X        --> X >u (MAXUINT-1)        --> X == 255
// (X+2) <u X        --> X >u (MAXUINT-2)        --> X > 253
// (X+MAXUINT) <u X  --> X >u (MAXUINT-MAXUINT)  --> X != 0
if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE) {
  Constant *R = ConstantInt::get(X->getType(),
                                 APInt::getMaxValue(C.getBitWidth()) - C);
  return new ICmpInst(ICmpInst::ICMP_UGT, X, R);
}

// (X+1) >u X        --> X <u (0-1)        --> X != 255
// (X+2) >u X        --> X <u (0-2)        --> X <u 254
// (X+MAXUINT) >u X  --> X <u (0-MAXUINT)  --> X <u 1  --> X == 0
if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE)
  return new ICmpInst(ICmpInst::ICMP_ULT, X,
                      ConstantInt::get(X->getType(), -C));

APInt SMax = APInt::getSignedMaxValue(C.getBitWidth());

// (X+ 1) <s X       --> X >s (MAXSINT-1)          --> X == 127
// (X+ 2) <s X       --> X >s (MAXSINT-2)          --> X >s 125
// (X+MAXSINT) <s X  --> X >s (MAXSINT-MAXSINT)    --> X >s 0
// (X+MINSINT) <s X  --> X >s (MAXSINT-MINSINT)    --> X >s -1
// (X+ -2) <s X      --> X >s (MAXSINT- -2)        --> X >s 126
// (X+ -1) <s X      --> X >s (MAXSINT- -1)        --> X != 127
if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE)
  return new ICmpInst(ICmpInst::ICMP_SGT, X,
                      ConstantInt::get(X->getType(), SMax - C));

// (X+ 1) >s X       --> X <s (MAXSINT-(1-1))       --> X != 127
// (X+ 2) >s X       --> X <s (MAXSINT-(2-1))       --> X <s 126
// (X+MAXSINT) >s X  --> X <s (MAXSINT-(MAXSINT-1)) --> X <s 1
// (X+MINSINT) >s X  --> X <s (MAXSINT-(MINSINT-1)) --> X <s -2
// (X+ -2) >s X      --> X <s (MAXSINT-(-2-1))      --> X <s -126
// (X+ -1) >s X      --> X <s (MAXSINT-(-1-1))      --> X == -128

assert(Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE)((Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE) ?
 static_cast<void> (0) : __assert_fail ("Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1144, __PRETTY_FUNCTION__));
return new ICmpInst(ICmpInst::ICMP_SLT, X,
                    ConstantInt::get(X->getType(), SMax - (C - 1)));
1147}

1149/// Handle "(icmp eq/ne (ashr/lshr AP2, A), AP1)" ->
1150/// (icmp eq/ne A, Log2(AP2/AP1)) ->
1151/// (icmp eq/ne A, Log2(AP2) - Log2(AP1)).
1152Instruction *InstCombiner::foldICmpShrConstConst(ICmpInst &I, Value *A,
                                               const APInt &AP1,
                                               const APInt &AP2) {
assert(I.isEquality() && "Cannot fold icmp gt/lt")((I.isEquality() && "Cannot fold icmp gt/lt") ? static_cast
<void> (0) : __assert_fail ("I.isEquality() && \"Cannot fold icmp gt/lt\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1155, __PRETTY_FUNCTION__));

auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
  if (I.getPredicate() == I.ICMP_NE)
    Pred = CmpInst::getInversePredicate(Pred);
  return new ICmpInst(Pred, LHS, RHS);
};

// Don't bother doing any work for cases which InstSimplify handles.
if (AP2.isNullValue())
  return nullptr;

bool IsAShr = isa<AShrOperator>(I.getOperand(0));
if (IsAShr) {
  if (AP2.isAllOnesValue())
    return nullptr;
  if (AP2.isNegative() != AP1.isNegative())
    return nullptr;
  if (AP2.sgt(AP1))
    return nullptr;
}

if (!AP1)
  // 'A' must be large enough to shift out the highest set bit.
  return getICmp(I.ICMP_UGT, A,
                 ConstantInt::get(A->getType(), AP2.logBase2()));

if (AP1 == AP2)
  return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));

int Shift;
if (IsAShr && AP1.isNegative())
  Shift = AP1.countLeadingOnes() - AP2.countLeadingOnes();
else
  Shift = AP1.countLeadingZeros() - AP2.countLeadingZeros();

if (Shift > 0) {
  if (IsAShr && AP1 == AP2.ashr(Shift)) {
    // There are multiple solutions if we are comparing against -1 and the LHS
    // of the ashr is not a power of two.
    if (AP1.isAllOnesValue() && !AP2.isPowerOf2())
      return getICmp(I.ICMP_UGE, A, ConstantInt::get(A->getType(), Shift));
    return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
  } else if (AP1 == AP2.lshr(Shift)) {
    return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));
  }
}

// Shifting const2 will never be equal to const1.
// FIXME: This should always be handled by InstSimplify?
auto *TorF = ConstantInt::get(I.getType(), I.getPredicate() == I.ICMP_NE);
return replaceInstUsesWith(I, TorF);
1207}

1209/// Handle "(icmp eq/ne (shl AP2, A), AP1)" ->
1210/// (icmp eq/ne A, TrailingZeros(AP1) - TrailingZeros(AP2)).
1211Instruction *InstCombiner::foldICmpShlConstConst(ICmpInst &I, Value *A,
                                               const APInt &AP1,
                                               const APInt &AP2) {
assert(I.isEquality() && "Cannot fold icmp gt/lt")((I.isEquality() && "Cannot fold icmp gt/lt") ? static_cast
<void> (0) : __assert_fail ("I.isEquality() && \"Cannot fold icmp gt/lt\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1214, __PRETTY_FUNCTION__));

auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
  if (I.getPredicate() == I.ICMP_NE)
    Pred = CmpInst::getInversePredicate(Pred);
  return new ICmpInst(Pred, LHS, RHS);
};

// Don't bother doing any work for cases which InstSimplify handles.
if (AP2.isNullValue())
  return nullptr;

unsigned AP2TrailingZeros = AP2.countTrailingZeros();

if (!AP1 && AP2TrailingZeros != 0)
  return getICmp(
      I.ICMP_UGE, A,
      ConstantInt::get(A->getType(), AP2.getBitWidth() - AP2TrailingZeros));

if (AP1 == AP2)
  return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));

// Get the distance between the lowest bits that are set.
int Shift = AP1.countTrailingZeros() - AP2TrailingZeros;

if (Shift > 0 && AP2.shl(Shift) == AP1)
  return getICmp(I.ICMP_EQ, A, ConstantInt::get(A->getType(), Shift));

// Shifting const2 will never be equal to const1.
// FIXME: This should always be handled by InstSimplify?
auto *TorF = ConstantInt::get(I.getType(), I.getPredicate() == I.ICMP_NE);
return replaceInstUsesWith(I, TorF);
1246}

1248/// The caller has matched a pattern of the form:
1249///   I = icmp ugt (add (add A, B), CI2), CI1
1250/// If this is of the form:
1251///   sum = a + b
1252///   if (sum+128 >u 255)
1253/// Then replace it with llvm.sadd.with.overflow.i8.
1254///
1255static Instruction *processUGT_ADDCST_ADD(ICmpInst &I, Value *A, Value *B,
                                        ConstantInt *CI2, ConstantInt *CI1,
                                        InstCombiner &IC) {
// The transformation we're trying to do here is to transform this into an
// llvm.sadd.with.overflow.  To do this, we have to replace the original add
// with a narrower add, and discard the add-with-constant that is part of the
// range check (if we can't eliminate it, this isn't profitable).

// In order to eliminate the add-with-constant, the compare can be its only
// use.
Instruction *AddWithCst = cast<Instruction>(I.getOperand(0));
if (!AddWithCst->hasOneUse())
  return nullptr;

// If CI2 is 2^7, 2^15, 2^31, then it might be an sadd.with.overflow.
if (!CI2->getValue().isPowerOf2())
  return nullptr;
unsigned NewWidth = CI2->getValue().countTrailingZeros();
if (NewWidth != 7 && NewWidth != 15 && NewWidth != 31)
  return nullptr;

// The width of the new add formed is 1 more than the bias.
++NewWidth;

// Check to see that CI1 is an all-ones value with NewWidth bits.
if (CI1->getBitWidth() == NewWidth ||
    CI1->getValue() != APInt::getLowBitsSet(CI1->getBitWidth(), NewWidth))
  return nullptr;

// This is only really a signed overflow check if the inputs have been
// sign-extended; check for that condition. For example, if CI2 is 2^31 and
// the operands of the add are 64 bits wide, we need at least 33 sign bits.
unsigned NeededSignBits = CI1->getBitWidth() - NewWidth + 1;
if (IC.ComputeNumSignBits(A, 0, &I) < NeededSignBits ||
    IC.ComputeNumSignBits(B, 0, &I) < NeededSignBits)
  return nullptr;

// In order to replace the original add with a narrower
// llvm.sadd.with.overflow, the only uses allowed are the add-with-constant
// and truncates that discard the high bits of the add.  Verify that this is
// the case.
Instruction *OrigAdd = cast<Instruction>(AddWithCst->getOperand(0));
for (User *U : OrigAdd->users()) {
  if (U == AddWithCst)
    continue;

  // Only accept truncates for now.  We would really like a nice recursive
  // predicate like SimplifyDemandedBits, but which goes downwards the use-def
  // chain to see which bits of a value are actually demanded.  If the
  // original add had another add which was then immediately truncated, we
  // could still do the transformation.
  TruncInst *TI = dyn_cast<TruncInst>(U);
  if (!TI || TI->getType()->getPrimitiveSizeInBits() > NewWidth)
    return nullptr;
}

// If the pattern matches, truncate the inputs to the narrower type and
// use the sadd_with_overflow intrinsic to efficiently compute both the
// result and the overflow bit.
Type *NewType = IntegerType::get(OrigAdd->getContext(), NewWidth);
Function *F = Intrinsic::getDeclaration(
    I.getModule(), Intrinsic::sadd_with_overflow, NewType);

InstCombiner::BuilderTy &Builder = IC.Builder;

// Put the new code above the original add, in case there are any uses of the
// add between the add and the compare.
Builder.SetInsertPoint(OrigAdd);

Value *TruncA = Builder.CreateTrunc(A, NewType, A->getName() + ".trunc");
Value *TruncB = Builder.CreateTrunc(B, NewType, B->getName() + ".trunc");
CallInst *Call = Builder.CreateCall(F, {TruncA, TruncB}, "sadd");
Value *Add = Builder.CreateExtractValue(Call, 0, "sadd.result");
Value *ZExt = Builder.CreateZExt(Add, OrigAdd->getType());

// The inner add was the result of the narrow add, zero extended to the
// wider type.  Replace it with the result computed by the intrinsic.
IC.replaceInstUsesWith(*OrigAdd, ZExt);

// The original icmp gets replaced with the overflow value.
return ExtractValueInst::Create(Call, 1, "sadd.overflow");
1336}

1338/// If we have:
1339///   icmp eq/ne (urem/srem %x, %y), 0
1340/// iff %y is a power-of-two, we can replace this with a bit test:
1341///   icmp eq/ne (and %x, (add %y, -1)), 0
1342Instruction *InstCombiner::foldIRemByPowerOfTwoToBitTest(ICmpInst &I) {
// This fold is only valid for equality predicates.
if (!I.isEquality())
  return nullptr;
ICmpInst::Predicate Pred;
Value *X, *Y, *Zero;
if (!match(&I, m_ICmp(Pred, m_OneUse(m_IRem(m_Value(X), m_Value(Y))),
                      m_CombineAnd(m_Zero(), m_Value(Zero)))))
  return nullptr;
if (!isKnownToBeAPowerOfTwo(Y, /*OrZero*/ true, 0, &I))
  return nullptr;
// This may increase instruction count, we don't enforce that Y is a constant.
Value *Mask = Builder.CreateAdd(Y, Constant::getAllOnesValue(Y->getType()));
Value *Masked = Builder.CreateAnd(X, Mask);
return ICmpInst::Create(Instruction::ICmp, Pred, Masked, Zero);
1357}

1359/// Fold equality-comparison between zero and any (maybe truncated) right-shift
1360/// by one-less-than-bitwidth into a sign test on the original value.
1361Instruction *InstCombiner::foldSignBitTest(ICmpInst &I) {
Instruction *Val;
ICmpInst::Predicate Pred;
if (!I.isEquality() || !match(&I, m_ICmp(Pred, m_Instruction(Val), m_Zero())))
  return nullptr;

Value *X;
Type *XTy;

Constant *C;
if (match(Val, m_TruncOrSelf(m_Shr(m_Value(X), m_Constant(C))))) {
  XTy = X->getType();
  unsigned XBitWidth = XTy->getScalarSizeInBits();
  if (!match(C, m_SpecificInt_ICMP(ICmpInst::Predicate::ICMP_EQ,
                                   APInt(XBitWidth, XBitWidth - 1))))
    return nullptr;
} else if (isa<BinaryOperator>(Val) &&
           (X = reassociateShiftAmtsOfTwoSameDirectionShifts(
                cast<BinaryOperator>(Val), SQ.getWithInstruction(Val),
                /*AnalyzeForSignBitExtraction=*/true))) {
  XTy = X->getType();
} else
  return nullptr;

return ICmpInst::Create(Instruction::ICmp,
                        Pred == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_SGE
                                                  : ICmpInst::ICMP_SLT,
                        X, ConstantInt::getNullValue(XTy));
1389}

1391// Handle  icmp pred X, 0
1392Instruction *InstCombiner::foldICmpWithZero(ICmpInst &Cmp) {
CmpInst::Predicate Pred = Cmp.getPredicate();
if (!match(Cmp.getOperand(1), m_Zero()))
  return nullptr;

// (icmp sgt smin(PosA, B) 0) -> (icmp sgt B 0)
if (Pred == ICmpInst::ICMP_SGT) {
  Value *A, *B;
  SelectPatternResult SPR = matchSelectPattern(Cmp.getOperand(0), A, B);
  if (SPR.Flavor == SPF_SMIN) {
    if (isKnownPositive(A, DL, 0, &AC, &Cmp, &DT))
      return new ICmpInst(Pred, B, Cmp.getOperand(1));
    if (isKnownPositive(B, DL, 0, &AC, &Cmp, &DT))
      return new ICmpInst(Pred, A, Cmp.getOperand(1));
  }
}

if (Instruction *New = foldIRemByPowerOfTwoToBitTest(Cmp))
  return New;

// Given:
//   icmp eq/ne (urem %x, %y), 0
// Iff %x has 0 or 1 bits set, and %y has at least 2 bits set, omit 'urem':
//   icmp eq/ne %x, 0
Value *X, *Y;
if (match(Cmp.getOperand(0), m_URem(m_Value(X), m_Value(Y))) &&
    ICmpInst::isEquality(Pred)) {
  KnownBits XKnown = computeKnownBits(X, 0, &Cmp);
  KnownBits YKnown = computeKnownBits(Y, 0, &Cmp);
  if (XKnown.countMaxPopulation() == 1 && YKnown.countMinPopulation() >= 2)
    return new ICmpInst(Pred, X, Cmp.getOperand(1));
}

return nullptr;
1426}

1428/// Fold icmp Pred X, C.
1429/// TODO: This code structure does not make sense. The saturating add fold
1430/// should be moved to some other helper and extended as noted below (it is also
1431/// possible that code has been made unnecessary - do we canonicalize IR to
1432/// overflow/saturating intrinsics or not?).
1433Instruction *InstCombiner::foldICmpWithConstant(ICmpInst &Cmp) {
// Match the following pattern, which is a common idiom when writing
// overflow-safe integer arithmetic functions. The source performs an addition
// in wider type and explicitly checks for overflow using comparisons against
// INT_MIN and INT_MAX. Simplify by using the sadd_with_overflow intrinsic.
//
// TODO: This could probably be generalized to handle other overflow-safe
// operations if we worked out the formulas to compute the appropriate magic
// constants.
//
// sum = a + b
// if (sum+128 >u 255)  ...  -> llvm.sadd.with.overflow.i8
CmpInst::Predicate Pred = Cmp.getPredicate();
Value *Op0 = Cmp.getOperand(0), *Op1 = Cmp.getOperand(1);
Value *A, *B;
ConstantInt *CI, *CI2; // I = icmp ugt (add (add A, B), CI2), CI
if (Pred == ICmpInst::ICMP_UGT && match(Op1, m_ConstantInt(CI)) &&
    match(Op0, m_Add(m_Add(m_Value(A), m_Value(B)), m_ConstantInt(CI2))))
  if (Instruction *Res = processUGT_ADDCST_ADD(Cmp, A, B, CI2, CI, *this))
    return Res;

return nullptr;
1455}

1457/// Canonicalize icmp instructions based on dominating conditions.
1458Instruction *InstCombiner::foldICmpWithDominatingICmp(ICmpInst &Cmp) {
// This is a cheap/incomplete check for dominance - just match a single
// predecessor with a conditional branch.
BasicBlock *CmpBB = Cmp.getParent();
BasicBlock *DomBB = CmpBB->getSinglePredecessor();
if (!DomBB)
  return nullptr;

Value *DomCond;
BasicBlock *TrueBB, *FalseBB;
if (!match(DomBB->getTerminator(), m_Br(m_Value(DomCond), TrueBB, FalseBB)))
  return nullptr;

assert((TrueBB == CmpBB || FalseBB == CmpBB) &&(((TrueBB == CmpBB || FalseBB == CmpBB) && "Predecessor block does not point to successor?"
) ? static_cast<void> (0) : __assert_fail ("(TrueBB == CmpBB || FalseBB == CmpBB) && \"Predecessor block does not point to successor?\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1472, __PRETTY_FUNCTION__))
       "Predecessor block does not point to successor?")(((TrueBB == CmpBB || FalseBB == CmpBB) && "Predecessor block does not point to successor?"
) ? static_cast<void> (0) : __assert_fail ("(TrueBB == CmpBB || FalseBB == CmpBB) && \"Predecessor block does not point to successor?\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1472, __PRETTY_FUNCTION__));

// The branch should get simplified. Don't bother simplifying this condition.
if (TrueBB == FalseBB)
  return nullptr;

// Try to simplify this compare to T/F based on the dominating condition.
Optional<bool> Imp = isImpliedCondition(DomCond, &Cmp, DL, TrueBB == CmpBB);
if (Imp)
  return replaceInstUsesWith(Cmp, ConstantInt::get(Cmp.getType(), *Imp));

CmpInst::Predicate Pred = Cmp.getPredicate();
Value *X = Cmp.getOperand(0), *Y = Cmp.getOperand(1);
ICmpInst::Predicate DomPred;
const APInt *C, *DomC;
if (match(DomCond, m_ICmp(DomPred, m_Specific(X), m_APInt(DomC))) &&
    match(Y, m_APInt(C))) {
  // We have 2 compares of a variable with constants. Calculate the constant
  // ranges of those compares to see if we can transform the 2nd compare:
  // DomBB:
  //   DomCond = icmp DomPred X, DomC
  //   br DomCond, CmpBB, FalseBB
  // CmpBB:
  //   Cmp = icmp Pred X, C
  ConstantRange CR = ConstantRange::makeAllowedICmpRegion(Pred, *C);
  ConstantRange DominatingCR =
      (CmpBB == TrueBB) ? ConstantRange::makeExactICmpRegion(DomPred, *DomC)
                        : ConstantRange::makeExactICmpRegion(
                              CmpInst::getInversePredicate(DomPred), *DomC);
  ConstantRange Intersection = DominatingCR.intersectWith(CR);
  ConstantRange Difference = DominatingCR.difference(CR);
  if (Intersection.isEmptySet())
    return replaceInstUsesWith(Cmp, Builder.getFalse());
  if (Difference.isEmptySet())
    return replaceInstUsesWith(Cmp, Builder.getTrue());

  // Canonicalizing a sign bit comparison that gets used in a branch,
  // pessimizes codegen by generating branch on zero instruction instead
  // of a test and branch. So we avoid canonicalizing in such situations
  // because test and branch instruction has better branch displacement
  // than compare and branch instruction.
  bool UnusedBit;
  bool IsSignBit = isSignBitCheck(Pred, *C, UnusedBit);
  if (Cmp.isEquality() || (IsSignBit && hasBranchUse(Cmp)))
    return nullptr;

  if (const APInt *EqC = Intersection.getSingleElement())
    return new ICmpInst(ICmpInst::ICMP_EQ, X, Builder.getInt(*EqC));
  if (const APInt *NeC = Difference.getSingleElement())
    return new ICmpInst(ICmpInst::ICMP_NE, X, Builder.getInt(*NeC));
}

return nullptr;
1525}

1527/// Fold icmp (trunc X, Y), C.
1528Instruction *InstCombiner::foldICmpTruncConstant(ICmpInst &Cmp,
                                               TruncInst *Trunc,
                                               const APInt &C) {
ICmpInst::Predicate Pred = Cmp.getPredicate();
Value *X = Trunc->getOperand(0);
if (C.isOneValue() && C.getBitWidth() > 1) {
  // icmp slt trunc(signum(V)) 1 --> icmp slt V, 1
  Value *V = nullptr;
  if (Pred == ICmpInst::ICMP_SLT && match(X, m_Signum(m_Value(V))))
    return new ICmpInst(ICmpInst::ICMP_SLT, V,
                        ConstantInt::get(V->getType(), 1));
}

if (Cmp.isEquality() && Trunc->hasOneUse()) {
  // Simplify icmp eq (trunc x to i8), 42 -> icmp eq x, 42|highbits if all
  // of the high bits truncated out of x are known.
  unsigned DstBits = Trunc->getType()->getScalarSizeInBits(),
           SrcBits = X->getType()->getScalarSizeInBits();
  KnownBits Known = computeKnownBits(X, 0, &Cmp);

  // If all the high bits are known, we can do this xform.
  if ((Known.Zero | Known.One).countLeadingOnes() >= SrcBits - DstBits) {
    // Pull in the high bits from known-ones set.
    APInt NewRHS = C.zext(SrcBits);
    NewRHS |= Known.One & APInt::getHighBitsSet(SrcBits, SrcBits - DstBits);
    return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), NewRHS));
  }
}

return nullptr;
1558}

1560/// Fold icmp (xor X, Y), C.
1561Instruction *InstCombiner::foldICmpXorConstant(ICmpInst &Cmp,
                                             BinaryOperator *Xor,
                                             const APInt &C) {
Value *X = Xor->getOperand(0);
Value *Y = Xor->getOperand(1);
const APInt *XorC;
if (!match(Y, m_APInt(XorC)))
  return nullptr;

// If this is a comparison that tests the signbit (X < 0) or (x > -1),
// fold the xor.
ICmpInst::Predicate Pred = Cmp.getPredicate();
bool TrueIfSigned = false;
if (isSignBitCheck(Cmp.getPredicate(), C, TrueIfSigned)) {

  // If the sign bit of the XorCst is not set, there is no change to
  // the operation, just stop using the Xor.
  if (!XorC->isNegative()) {
    Cmp.setOperand(0, X);
    Worklist.Add(Xor);
    return &Cmp;
  }

  // Emit the opposite comparison.
  if (TrueIfSigned)
    return new ICmpInst(ICmpInst::ICMP_SGT, X,
                        ConstantInt::getAllOnesValue(X->getType()));
  else
    return new ICmpInst(ICmpInst::ICMP_SLT, X,
                        ConstantInt::getNullValue(X->getType()));
}

if (Xor->hasOneUse()) {
  // (icmp u/s (xor X SignMask), C) -> (icmp s/u X, (xor C SignMask))
  if (!Cmp.isEquality() && XorC->isSignMask()) {
    Pred = Cmp.isSigned() ? Cmp.getUnsignedPredicate()
                          : Cmp.getSignedPredicate();
    return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), C ^ *XorC));
  }

  // (icmp u/s (xor X ~SignMask), C) -> (icmp s/u X, (xor C ~SignMask))
  if (!Cmp.isEquality() && XorC->isMaxSignedValue()) {
    Pred = Cmp.isSigned() ? Cmp.getUnsignedPredicate()
                          : Cmp.getSignedPredicate();
    Pred = Cmp.getSwappedPredicate(Pred);
    return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), C ^ *XorC));
  }
}

// Mask constant magic can eliminate an 'xor' with unsigned compares.
if (Pred == ICmpInst::ICMP_UGT) {
  // (xor X, ~C) >u C --> X <u ~C (when C+1 is a power of 2)
  if (*XorC == ~C && (C + 1).isPowerOf2())
    return new ICmpInst(ICmpInst::ICMP_ULT, X, Y);
  // (xor X, C) >u C --> X >u C (when C+1 is a power of 2)
  if (*XorC == C && (C + 1).isPowerOf2())
    return new ICmpInst(ICmpInst::ICMP_UGT, X, Y);
}
if (Pred == ICmpInst::ICMP_ULT) {
  // (xor X, -C) <u C --> X >u ~C (when C is a power of 2)
  if (*XorC == -C && C.isPowerOf2())
    return new ICmpInst(ICmpInst::ICMP_UGT, X,
                        ConstantInt::get(X->getType(), ~C));
  // (xor X, C) <u C --> X >u ~C (when -C is a power of 2)
  if (*XorC == C && (-C).isPowerOf2())
    return new ICmpInst(ICmpInst::ICMP_UGT, X,
                        ConstantInt::get(X->getType(), ~C));
}
return nullptr;
1630}

1632/// Fold icmp (and (sh X, Y), C2), C1.
1633Instruction *InstCombiner::foldICmpAndShift(ICmpInst &Cmp, BinaryOperator *And,
                                          const APInt &C1, const APInt &C2) {
BinaryOperator *Shift = dyn_cast<BinaryOperator>(And->getOperand(0));
if (!Shift || !Shift->isShift())
  return nullptr;

// If this is: (X >> C3) & C2 != C1 (where any shift and any compare could
// exist), turn it into (X & (C2 << C3)) != (C1 << C3). This happens a LOT in
// code produced by the clang front-end, for bitfield access.
// This seemingly simple opportunity to fold away a shift turns out to be
// rather complicated. See PR17827 for details.
unsigned ShiftOpcode = Shift->getOpcode();
bool IsShl = ShiftOpcode == Instruction::Shl;
const APInt *C3;
if (match(Shift->getOperand(1), m_APInt(C3))) {
  bool CanFold = false;
  if (ShiftOpcode == Instruction::Shl) {
    // For a left shift, we can fold if the comparison is not signed. We can
    // also fold a signed comparison if the mask value and comparison value
    // are not negative. These constraints may not be obvious, but we can
    // prove that they are correct using an SMT solver.
    if (!Cmp.isSigned() || (!C2.isNegative() && !C1.isNegative()))
      CanFold = true;
  } else {
    bool IsAshr = ShiftOpcode == Instruction::AShr;
    // For a logical right shift, we can fold if the comparison is not signed.
    // We can also fold a signed comparison if the shifted mask value and the
    // shifted comparison value are not negative. These constraints may not be
    // obvious, but we can prove that they are correct using an SMT solver.
    // For an arithmetic shift right we can do the same, if we ensure
    // the And doesn't use any bits being shifted in. Normally these would
    // be turned into lshr by SimplifyDemandedBits, but not if there is an
    // additional user.
    if (!IsAshr || (C2.shl(*C3).lshr(*C3) == C2)) {
      if (!Cmp.isSigned() ||
          (!C2.shl(*C3).isNegative() && !C1.shl(*C3).isNegative()))
        CanFold = true;
    }
  }

  if (CanFold) {
    APInt NewCst = IsShl ? C1.lshr(*C3) : C1.shl(*C3);
    APInt SameAsC1 = IsShl ? NewCst.shl(*C3) : NewCst.lshr(*C3);
    // Check to see if we are shifting out any of the bits being compared.
    if (SameAsC1 != C1) {
      // If we shifted bits out, the fold is not going to work out. As a
      // special case, check to see if this means that the result is always
      // true or false now.
      if (Cmp.getPredicate() == ICmpInst::ICMP_EQ)
        return replaceInstUsesWith(Cmp, ConstantInt::getFalse(Cmp.getType()));
      if (Cmp.getPredicate() == ICmpInst::ICMP_NE)
        return replaceInstUsesWith(Cmp, ConstantInt::getTrue(Cmp.getType()));
    } else {
      Cmp.setOperand(1, ConstantInt::get(And->getType(), NewCst));
      APInt NewAndCst = IsShl ? C2.lshr(*C3) : C2.shl(*C3);
      And->setOperand(1, ConstantInt::get(And->getType(), NewAndCst));
      And->setOperand(0, Shift->getOperand(0));
      Worklist.Add(Shift); // Shift is dead.
      return &Cmp;
    }
  }
}

// Turn ((X >> Y) & C2) == 0  into  (X & (C2 << Y)) == 0.  The latter is
// preferable because it allows the C2 << Y expression to be hoisted out of a
// loop if Y is invariant and X is not.
if (Shift->hasOneUse() && C1.isNullValue() && Cmp.isEquality() &&
    !Shift->isArithmeticShift() && !isa<Constant>(Shift->getOperand(0))) {
  // Compute C2 << Y.
  Value *NewShift =
      IsShl ? Builder.CreateLShr(And->getOperand(1), Shift->getOperand(1))
            : Builder.CreateShl(And->getOperand(1), Shift->getOperand(1));

  // Compute X & (C2 << Y).
  Value *NewAnd = Builder.CreateAnd(Shift->getOperand(0), NewShift);
  Cmp.setOperand(0, NewAnd);
  return &Cmp;
}

return nullptr;
1713}

1715/// Fold icmp (and X, C2), C1.
1716Instruction *InstCombiner::foldICmpAndConstConst(ICmpInst &Cmp,
                                               BinaryOperator *And,
                                               const APInt &C1) {
bool isICMP_NE = Cmp.getPredicate() == ICmpInst::ICMP_NE;

// For vectors: icmp ne (and X, 1), 0 --> trunc X to N x i1
// TODO: We canonicalize to the longer form for scalars because we have
// better analysis/folds for icmp, and codegen may be better with icmp.
if (isICMP_NE && Cmp.getType()->isVectorTy() && C1.isNullValue() &&
    match(And->getOperand(1), m_One()))
  return new TruncInst(And->getOperand(0), Cmp.getType());

const APInt *C2;
Value *X;
if (!match(And, m_And(m_Value(X), m_APInt(C2))))
  return nullptr;

// Don't perform the following transforms if the AND has multiple uses
if (!And->hasOneUse())
  return nullptr;

if (Cmp.isEquality() && C1.isNullValue()) {
  // Restrict this fold to single-use 'and' (PR10267).
  // Replace (and X, (1 << size(X)-1) != 0) with X s< 0
  if (C2->isSignMask()) {
    Constant *Zero = Constant::getNullValue(X->getType());
    auto NewPred = isICMP_NE ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_SGE;
    return new ICmpInst(NewPred, X, Zero);
  }

  // Restrict this fold only for single-use 'and' (PR10267).
  // ((%x & C) == 0) --> %x u< (-C)  iff (-C) is power of two.
  if ((~(*C2) + 1).isPowerOf2()) {
    Constant *NegBOC =
        ConstantExpr::getNeg(cast<Constant>(And->getOperand(1)));
    auto NewPred = isICMP_NE ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_ULT;
    return new ICmpInst(NewPred, X, NegBOC);
  }
}

// If the LHS is an 'and' of a truncate and we can widen the and/compare to
// the input width without changing the value produced, eliminate the cast:
//
// icmp (and (trunc W), C2), C1 -> icmp (and W, C2'), C1'
//
// We can do this transformation if the constants do not have their sign bits
// set or if it is an equality comparison. Extending a relational comparison
// when we're checking the sign bit would not work.
Value *W;
if (match(And->getOperand(0), m_OneUse(m_Trunc(m_Value(W)))) &&
    (Cmp.isEquality() || (!C1.isNegative() && !C2->isNegative()))) {
  // TODO: Is this a good transform for vectors? Wider types may reduce
  // throughput. Should this transform be limited (even for scalars) by using
  // shouldChangeType()?
  if (!Cmp.getType()->isVectorTy()) {
    Type *WideType = W->getType();
    unsigned WideScalarBits = WideType->getScalarSizeInBits();
    Constant *ZextC1 = ConstantInt::get(WideType, C1.zext(WideScalarBits));
    Constant *ZextC2 = ConstantInt::get(WideType, C2->zext(WideScalarBits));
    Value *NewAnd = Builder.CreateAnd(W, ZextC2, And->getName());
    return new ICmpInst(Cmp.getPredicate(), NewAnd, ZextC1);
  }
}

if (Instruction *I = foldICmpAndShift(Cmp, And, C1, *C2))
  return I;

// (icmp pred (and (or (lshr A, B), A), 1), 0) -->
// (icmp pred (and A, (or (shl 1, B), 1), 0))
//
// iff pred isn't signed
if (!Cmp.isSigned() && C1.isNullValue() && And->getOperand(0)->hasOneUse() &&
    match(And->getOperand(1), m_One())) {
  Constant *One = cast<Constant>(And->getOperand(1));
  Value *Or = And->getOperand(0);
  Value *A, *B, *LShr;
  if (match(Or, m_Or(m_Value(LShr), m_Value(A))) &&
      match(LShr, m_LShr(m_Specific(A), m_Value(B)))) {
    unsigned UsesRemoved = 0;
    if (And->hasOneUse())
      ++UsesRemoved;
    if (Or->hasOneUse())
      ++UsesRemoved;
    if (LShr->hasOneUse())
      ++UsesRemoved;

    // Compute A & ((1 << B) | 1)
    Value *NewOr = nullptr;
    if (auto *C = dyn_cast<Constant>(B)) {
      if (UsesRemoved >= 1)
        NewOr = ConstantExpr::getOr(ConstantExpr::getNUWShl(One, C), One);
    } else {
      if (UsesRemoved >= 3)
        NewOr = Builder.CreateOr(Builder.CreateShl(One, B, LShr->getName(),
                                                   /*HasNUW=*/true),
                                 One, Or->getName());
    }
    if (NewOr) {
      Value *NewAnd = Builder.CreateAnd(A, NewOr, And->getName());
      Cmp.setOperand(0, NewAnd);
      return &Cmp;
    }
  }
}

return nullptr;
1822}

1824/// Fold icmp (and X, Y), C.
1825Instruction *InstCombiner::foldICmpAndConstant(ICmpInst &Cmp,
                                             BinaryOperator *And,
                                             const APInt &C) {
if (Instruction *I = foldICmpAndConstConst(Cmp, And, C))
  return I;

// TODO: These all require that Y is constant too, so refactor with the above.

// Try to optimize things like "A[i] & 42 == 0" to index computations.
Value *X = And->getOperand(0);
Value *Y = And->getOperand(1);
if (auto *LI = dyn_cast<LoadInst>(X))
  if (auto *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0)))
    if (auto *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
      if (GV->isConstant() && GV->hasDefinitiveInitializer() &&
          !LI->isVolatile() && isa<ConstantInt>(Y)) {
        ConstantInt *C2 = cast<ConstantInt>(Y);
        if (Instruction *Res = foldCmpLoadFromIndexedGlobal(GEP, GV, Cmp, C2))
          return Res;
      }

if (!Cmp.isEquality())
  return nullptr;

// X & -C == -C -> X >  u ~C
// X & -C != -C -> X <= u ~C
//   iff C is a power of 2
if (Cmp.getOperand(1) == Y && (-C).isPowerOf2()) {
  auto NewPred = Cmp.getPredicate() == CmpInst::ICMP_EQ ? CmpInst::ICMP_UGT
                                                        : CmpInst::ICMP_ULE;
  return new ICmpInst(NewPred, X, SubOne(cast<Constant>(Cmp.getOperand(1))));
}

// (X & C2) == 0 -> (trunc X) >= 0
// (X & C2) != 0 -> (trunc X) <  0
//   iff C2 is a power of 2 and it masks the sign bit of a legal integer type.
const APInt *C2;
if (And->hasOneUse() && C.isNullValue() && match(Y, m_APInt(C2))) {
  int32_t ExactLogBase2 = C2->exactLogBase2();
  if (ExactLogBase2 != -1 && DL.isLegalInteger(ExactLogBase2 + 1)) {
    Type *NTy = IntegerType::get(Cmp.getContext(), ExactLogBase2 + 1);
    if (And->getType()->isVectorTy())
      NTy = VectorType::get(NTy, And->getType()->getVectorNumElements());
    Value *Trunc = Builder.CreateTrunc(X, NTy);
    auto NewPred = Cmp.getPredicate() == CmpInst::ICMP_EQ ? CmpInst::ICMP_SGE
                                                          : CmpInst::ICMP_SLT;
    return new ICmpInst(NewPred, Trunc, Constant::getNullValue(NTy));
  }
}

return nullptr;
1876}

1878/// Fold icmp (or X, Y), C.
1879Instruction *InstCombiner::foldICmpOrConstant(ICmpInst &Cmp, BinaryOperator *Or,
                                            const APInt &C) {
ICmpInst::Predicate Pred = Cmp.getPredicate();
if (C.isOneValue()) {
  // icmp slt signum(V) 1 --> icmp slt V, 1
  Value *V = nullptr;
  if (Pred == ICmpInst::ICMP_SLT && match(Or, m_Signum(m_Value(V))))
    return new ICmpInst(ICmpInst::ICMP_SLT, V,
                        ConstantInt::get(V->getType(), 1));
}

Value *OrOp0 = Or->getOperand(0), *OrOp1 = Or->getOperand(1);
if (Cmp.isEquality() && Cmp.getOperand(1) == OrOp1) {
  // X | C == C --> X <=u C
  // X | C != C --> X  >u C
  //   iff C+1 is a power of 2 (C is a bitmask of the low bits)
  if ((C + 1).isPowerOf2()) {
    Pred = (Pred == CmpInst::ICMP_EQ) ? CmpInst::ICMP_ULE : CmpInst::ICMP_UGT;
    return new ICmpInst(Pred, OrOp0, OrOp1);
  }
  // More general: are all bits outside of a mask constant set or not set?
  // X | C == C --> (X & ~C) == 0
  // X | C != C --> (X & ~C) != 0
  if (Or->hasOneUse()) {
    Value *A = Builder.CreateAnd(OrOp0, ~C);
    return new ICmpInst(Pred, A, ConstantInt::getNullValue(OrOp0->getType()));
  }
}

if (!Cmp.isEquality() || !C.isNullValue() || !Or->hasOneUse())
  return nullptr;

Value *P, *Q;
if (match(Or, m_Or(m_PtrToInt(m_Value(P)), m_PtrToInt(m_Value(Q))))) {
  // Simplify icmp eq (or (ptrtoint P), (ptrtoint Q)), 0
  // -> and (icmp eq P, null), (icmp eq Q, null).
  Value *CmpP =
      Builder.CreateICmp(Pred, P, ConstantInt::getNullValue(P->getType()));
  Value *CmpQ =
      Builder.CreateICmp(Pred, Q, ConstantInt::getNullValue(Q->getType()));
  auto BOpc = Pred == CmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
  return BinaryOperator::Create(BOpc, CmpP, CmpQ);
}

// Are we using xors to bitwise check for a pair of (in)equalities? Convert to
// a shorter form that has more potential to be folded even further.
Value *X1, *X2, *X3, *X4;
if (match(OrOp0, m_OneUse(m_Xor(m_Value(X1), m_Value(X2)))) &&
    match(OrOp1, m_OneUse(m_Xor(m_Value(X3), m_Value(X4))))) {
  // ((X1 ^ X2) || (X3 ^ X4)) == 0 --> (X1 == X2) && (X3 == X4)
  // ((X1 ^ X2) || (X3 ^ X4)) != 0 --> (X1 != X2) || (X3 != X4)
  Value *Cmp12 = Builder.CreateICmp(Pred, X1, X2);
  Value *Cmp34 = Builder.CreateICmp(Pred, X3, X4);
  auto BOpc = Pred == CmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
  return BinaryOperator::Create(BOpc, Cmp12, Cmp34);
}

return nullptr;
1937}

1939/// Fold icmp (mul X, Y), C.
1940Instruction *InstCombiner::foldICmpMulConstant(ICmpInst &Cmp,
                                             BinaryOperator *Mul,
                                             const APInt &C) {
const APInt *MulC;
if (!match(Mul->getOperand(1), m_APInt(MulC)))
  return nullptr;

// If this is a test of the sign bit and the multiply is sign-preserving with
// a constant operand, use the multiply LHS operand instead.
ICmpInst::Predicate Pred = Cmp.getPredicate();
if (isSignTest(Pred, C) && Mul->hasNoSignedWrap()) {
  if (MulC->isNegative())
    Pred = ICmpInst::getSwappedPredicate(Pred);
  return new ICmpInst(Pred, Mul->getOperand(0),
                      Constant::getNullValue(Mul->getType()));
}

return nullptr;
1958}

1960/// Fold icmp (shl 1, Y), C.
1961static Instruction *foldICmpShlOne(ICmpInst &Cmp, Instruction *Shl,
                                 const APInt &C) {
Value *Y;
if (!match(Shl, m_Shl(m_One(), m_Value(Y))))
  return nullptr;

Type *ShiftType = Shl->getType();
unsigned TypeBits = C.getBitWidth();
bool CIsPowerOf2 = C.isPowerOf2();
ICmpInst::Predicate Pred = Cmp.getPredicate();
if (Cmp.isUnsigned()) {
  // (1 << Y) pred C -> Y pred Log2(C)
  if (!CIsPowerOf2) {
    // (1 << Y) <  30 -> Y <= 4
    // (1 << Y) <= 30 -> Y <= 4
    // (1 << Y) >= 30 -> Y >  4
    // (1 << Y) >  30 -> Y >  4
    if (Pred == ICmpInst::ICMP_ULT)
      Pred = ICmpInst::ICMP_ULE;
    else if (Pred == ICmpInst::ICMP_UGE)
      Pred = ICmpInst::ICMP_UGT;
  }

  // (1 << Y) >= 2147483648 -> Y >= 31 -> Y == 31
  // (1 << Y) <  2147483648 -> Y <  31 -> Y != 31
  unsigned CLog2 = C.logBase2();
  if (CLog2 == TypeBits - 1) {
    if (Pred == ICmpInst::ICMP_UGE)
      Pred = ICmpInst::ICMP_EQ;
    else if (Pred == ICmpInst::ICMP_ULT)
      Pred = ICmpInst::ICMP_NE;
  }
  return new ICmpInst(Pred, Y, ConstantInt::get(ShiftType, CLog2));
} else if (Cmp.isSigned()) {
  Constant *BitWidthMinusOne = ConstantInt::get(ShiftType, TypeBits - 1);
  if (C.isAllOnesValue()) {
    // (1 << Y) <= -1 -> Y == 31
    if (Pred == ICmpInst::ICMP_SLE)
      return new ICmpInst(ICmpInst::ICMP_EQ, Y, BitWidthMinusOne);

    // (1 << Y) >  -1 -> Y != 31
    if (Pred == ICmpInst::ICMP_SGT)
      return new ICmpInst(ICmpInst::ICMP_NE, Y, BitWidthMinusOne);
  } else if (!C) {
    // (1 << Y) <  0 -> Y == 31
    // (1 << Y) <= 0 -> Y == 31
    if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE)
      return new ICmpInst(ICmpInst::ICMP_EQ, Y, BitWidthMinusOne);

    // (1 << Y) >= 0 -> Y != 31
    // (1 << Y) >  0 -> Y != 31
    if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE)
      return new ICmpInst(ICmpInst::ICMP_NE, Y, BitWidthMinusOne);
  }
} else if (Cmp.isEquality() && CIsPowerOf2) {
  return new ICmpInst(Pred, Y, ConstantInt::get(ShiftType, C.logBase2()));
}

return nullptr;
2020}

2022/// Fold icmp (shl X, Y), C.
2023Instruction *InstCombiner::foldICmpShlConstant(ICmpInst &Cmp,
                                             BinaryOperator *Shl,
                                             const APInt &C) {
const APInt *ShiftVal;
if (Cmp.isEquality() && match(Shl->getOperand(0), m_APInt(ShiftVal)))
  return foldICmpShlConstConst(Cmp, Shl->getOperand(1), C, *ShiftVal);

const APInt *ShiftAmt;
if (!match(Shl->getOperand(1), m_APInt(ShiftAmt)))
  return foldICmpShlOne(Cmp, Shl, C);

// Check that the shift amount is in range. If not, don't perform undefined
// shifts. When the shift is visited, it will be simplified.
unsigned TypeBits = C.getBitWidth();
if (ShiftAmt->uge(TypeBits))
  return nullptr;

ICmpInst::Predicate Pred = Cmp.getPredicate();
Value *X = Shl->getOperand(0);
Type *ShType = Shl->getType();

// NSW guarantees that we are only shifting out sign bits from the high bits,
// so we can ASHR the compare constant without needing a mask and eliminate
// the shift.
if (Shl->hasNoSignedWrap()) {
  if (Pred == ICmpInst::ICMP_SGT) {
    // icmp Pred (shl nsw X, ShiftAmt), C --> icmp Pred X, (C >>s ShiftAmt)
    APInt ShiftedC = C.ashr(*ShiftAmt);
    return new ICmpInst(Pred, X, ConstantInt::get(ShType, ShiftedC));
  }
  if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_NE) &&
      C.ashr(*ShiftAmt).shl(*ShiftAmt) == C) {
    APInt ShiftedC = C.ashr(*ShiftAmt);
    return new ICmpInst(Pred, X, ConstantInt::get(ShType, ShiftedC));
  }
  if (Pred == ICmpInst::ICMP_SLT) {
    // SLE is the same as above, but SLE is canonicalized to SLT, so convert:
    // (X << S) <=s C is equiv to X <=s (C >> S) for all C
    // (X << S) <s (C + 1) is equiv to X <s (C >> S) + 1 if C <s SMAX
    // (X << S) <s C is equiv to X <s ((C - 1) >> S) + 1 if C >s SMIN
    assert(!C.isMinSignedValue() && "Unexpected icmp slt")((!C.isMinSignedValue() && "Unexpected icmp slt") ? static_cast
<void> (0) : __assert_fail ("!C.isMinSignedValue() && \"Unexpected icmp slt\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2063, __PRETTY_FUNCTION__));
    APInt ShiftedC = (C - 1).ashr(*ShiftAmt) + 1;
    return new ICmpInst(Pred, X, ConstantInt::get(ShType, ShiftedC));
  }
  // If this is a signed comparison to 0 and the shift is sign preserving,
  // use the shift LHS operand instead; isSignTest may change 'Pred', so only
  // do that if we're sure to not continue on in this function.
  if (isSignTest(Pred, C))
    return new ICmpInst(Pred, X, Constant::getNullValue(ShType));
}

// NUW guarantees that we are only shifting out zero bits from the high bits,
// so we can LSHR the compare constant without needing a mask and eliminate
// the shift.
if (Shl->hasNoUnsignedWrap()) {
  if (Pred == ICmpInst::ICMP_UGT) {
    // icmp Pred (shl nuw X, ShiftAmt), C --> icmp Pred X, (C >>u ShiftAmt)
    APInt ShiftedC = C.lshr(*ShiftAmt);
    return new ICmpInst(Pred, X, ConstantInt::get(ShType, ShiftedC));
  }
  if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_NE) &&
      C.lshr(*ShiftAmt).shl(*ShiftAmt) == C) {
    APInt ShiftedC = C.lshr(*ShiftAmt);
    return new ICmpInst(Pred, X, ConstantInt::get(ShType, ShiftedC));
  }
  if (Pred == ICmpInst::ICMP_ULT) {
    // ULE is the same as above, but ULE is canonicalized to ULT, so convert:
    // (X << S) <=u C is equiv to X <=u (C >> S) for all C
    // (X << S) <u (C + 1) is equiv to X <u (C >> S) + 1 if C <u ~0u
    // (X << S) <u C is equiv to X <u ((C - 1) >> S) + 1 if C >u 0
    assert(C.ugt(0) && "ult 0 should have been eliminated")((C.ugt(0) && "ult 0 should have been eliminated") ? static_cast
<void> (0) : __assert_fail ("C.ugt(0) && \"ult 0 should have been eliminated\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2093, __PRETTY_FUNCTION__));
    APInt ShiftedC = (C - 1).lshr(*ShiftAmt) + 1;
    return new ICmpInst(Pred, X, ConstantInt::get(ShType, ShiftedC));
  }
}

if (Cmp.isEquality() && Shl->hasOneUse()) {
  // Strength-reduce the shift into an 'and'.
  Constant *Mask = ConstantInt::get(
      ShType,
      APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt->getZExtValue()));
  Value *And = Builder.CreateAnd(X, Mask, Shl->getName() + ".mask");
  Constant *LShrC = ConstantInt::get(ShType, C.lshr(*ShiftAmt));
  return new ICmpInst(Pred, And, LShrC);
}

// Otherwise, if this is a comparison of the sign bit, simplify to and/test.
bool TrueIfSigned = false;
if (Shl->hasOneUse() && isSignBitCheck(Pred, C, TrueIfSigned)) {
  // (X << 31) <s 0  --> (X & 1) != 0
  Constant *Mask = ConstantInt::get(
      ShType,
      APInt::getOneBitSet(TypeBits, TypeBits - ShiftAmt->getZExtValue() - 1));
  Value *And = Builder.CreateAnd(X, Mask, Shl->getName() + ".mask");
  return new ICmpInst(TrueIfSigned ? ICmpInst::ICMP_NE : ICmpInst::ICMP_EQ,
                      And, Constant::getNullValue(ShType));
}

// Simplify 'shl' inequality test into 'and' equality test.
if (Cmp.isUnsigned() && Shl->hasOneUse()) {
  // (X l<< C2) u<=/u> C1 iff C1+1 is power of two -> X & (~C1 l>> C2) ==/!= 0
  if ((C + 1).isPowerOf2() &&
      (Pred == ICmpInst::ICMP_ULE || Pred == ICmpInst::ICMP_UGT)) {
    Value *And = Builder.CreateAnd(X, (~C).lshr(ShiftAmt->getZExtValue()));
    return new ICmpInst(Pred == ICmpInst::ICMP_ULE ? ICmpInst::ICMP_EQ
                                                   : ICmpInst::ICMP_NE,
                        And, Constant::getNullValue(ShType));
  }
  // (X l<< C2) u</u>= C1 iff C1 is power of two -> X & (-C1 l>> C2) ==/!= 0
  if (C.isPowerOf2() &&
      (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_UGE)) {
    Value *And =
        Builder.CreateAnd(X, (~(C - 1)).lshr(ShiftAmt->getZExtValue()));
    return new ICmpInst(Pred == ICmpInst::ICMP_ULT ? ICmpInst::ICMP_EQ
                                                   : ICmpInst::ICMP_NE,
                        And, Constant::getNullValue(ShType));
  }
}

// Transform (icmp pred iM (shl iM %v, N), C)
// -> (icmp pred i(M-N) (trunc %v iM to i(M-N)), (trunc (C>>N))
// Transform the shl to a trunc if (trunc (C>>N)) has no loss and M-N.
// This enables us to get rid of the shift in favor of a trunc that may be
// free on the target. It has the additional benefit of comparing to a
// smaller constant that may be more target-friendly.
unsigned Amt = ShiftAmt->getLimitedValue(TypeBits - 1);
if (Shl->hasOneUse() && Amt != 0 && C.countTrailingZeros() >= Amt &&
    DL.isLegalInteger(TypeBits - Amt)) {
  Type *TruncTy = IntegerType::get(Cmp.getContext(), TypeBits - Amt);
  if (ShType->isVectorTy())
    TruncTy = VectorType::get(TruncTy, ShType->getVectorNumElements());
  Constant *NewC =
      ConstantInt::get(TruncTy, C.ashr(*ShiftAmt).trunc(TypeBits - Amt));
  return new ICmpInst(Pred, Builder.CreateTrunc(X, TruncTy), NewC);
}

return nullptr;
2160}

2162/// Fold icmp ({al}shr X, Y), C.
2163Instruction *InstCombiner::foldICmpShrConstant(ICmpInst &Cmp,
                                             BinaryOperator *Shr,
                                             const APInt &C) {
// An exact shr only shifts out zero bits, so:
// icmp eq/ne (shr X, Y), 0 --> icmp eq/ne X, 0
Value *X = Shr->getOperand(0);
CmpInst::Predicate Pred = Cmp.getPredicate();
if (Cmp.isEquality() && Shr->isExact() && Shr->hasOneUse() &&
    C.isNullValue())
  return new ICmpInst(Pred, X, Cmp.getOperand(1));

const APInt *ShiftVal;
if (Cmp.isEquality() && match(Shr->getOperand(0), m_APInt(ShiftVal)))
  return foldICmpShrConstConst(Cmp, Shr->getOperand(1), C, *ShiftVal);

const APInt *ShiftAmt;
if (!match(Shr->getOperand(1), m_APInt(ShiftAmt)))
  return nullptr;

// Check that the shift amount is in range. If not, don't perform undefined
// shifts. When the shift is visited it will be simplified.
unsigned TypeBits = C.getBitWidth();
unsigned ShAmtVal = ShiftAmt->getLimitedValue(TypeBits);
if (ShAmtVal >= TypeBits || ShAmtVal == 0)
  return nullptr;

bool IsAShr = Shr->getOpcode() == Instruction::AShr;
bool IsExact = Shr->isExact();
Type *ShrTy = Shr->getType();
// TODO: If we could guarantee that InstSimplify would handle all of the
// constant-value-based preconditions in the folds below, then we could assert
// those conditions rather than checking them. This is difficult because of
// undef/poison (PR34838).
if (IsAShr) {
  if (Pred == CmpInst::ICMP_SLT || (Pred == CmpInst::ICMP_SGT && IsExact)) {
    // icmp slt (ashr X, ShAmtC), C --> icmp slt X, (C << ShAmtC)
    // icmp sgt (ashr exact X, ShAmtC), C --> icmp sgt X, (C << ShAmtC)
    APInt ShiftedC = C.shl(ShAmtVal);
    if (ShiftedC.ashr(ShAmtVal) == C)
      return new ICmpInst(Pred, X, ConstantInt::get(ShrTy, ShiftedC));
  }
  if (Pred == CmpInst::ICMP_SGT) {
    // icmp sgt (ashr X, ShAmtC), C --> icmp sgt X, ((C + 1) << ShAmtC) - 1
    APInt ShiftedC = (C + 1).shl(ShAmtVal) - 1;
    if (!C.isMaxSignedValue() && !(C + 1).shl(ShAmtVal).isMinSignedValue() &&
        (ShiftedC + 1).ashr(ShAmtVal) == (C + 1))
      return new ICmpInst(Pred, X, ConstantInt::get(ShrTy, ShiftedC));
  }
} else {
  if (Pred == CmpInst::ICMP_ULT || (Pred == CmpInst::ICMP_UGT && IsExact)) {
    // icmp ult (lshr X, ShAmtC), C --> icmp ult X, (C << ShAmtC)
    // icmp ugt (lshr exact X, ShAmtC), C --> icmp ugt X, (C << ShAmtC)
    APInt ShiftedC = C.shl(ShAmtVal);
    if (ShiftedC.lshr(ShAmtVal) == C)
      return new ICmpInst(Pred, X, ConstantInt::get(ShrTy, ShiftedC));
  }
  if (Pred == CmpInst::ICMP_UGT) {
    // icmp ugt (lshr X, ShAmtC), C --> icmp ugt X, ((C + 1) << ShAmtC) - 1
    APInt ShiftedC = (C + 1).shl(ShAmtVal) - 1;
    if ((ShiftedC + 1).lshr(ShAmtVal) == (C + 1))
      return new ICmpInst(Pred, X, ConstantInt::get(ShrTy, ShiftedC));
  }
}

if (!Cmp.isEquality())
  return nullptr;

// Handle equality comparisons of shift-by-constant.

// If the comparison constant changes with the shift, the comparison cannot
// succeed (bits of the comparison constant cannot match the shifted value).
// This should be known by InstSimplify and already be folded to true/false.
assert(((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) ||((((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) ||
 (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) &&
 "Expected icmp+shr simplify did not occur.") ? static_cast<
void> (0) : __assert_fail ("((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) || (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) && \"Expected icmp+shr simplify did not occur.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2237, __PRETTY_FUNCTION__))
        (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) &&((((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) ||
 (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) &&
 "Expected icmp+shr simplify did not occur.") ? static_cast<
void> (0) : __assert_fail ("((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) || (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) && \"Expected icmp+shr simplify did not occur.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2237, __PRETTY_FUNCTION__))
       "Expected icmp+shr simplify did not occur.")((((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) ||
 (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) &&
 "Expected icmp+shr simplify did not occur.") ? static_cast<
void> (0) : __assert_fail ("((IsAShr && C.shl(ShAmtVal).ashr(ShAmtVal) == C) || (!IsAShr && C.shl(ShAmtVal).lshr(ShAmtVal) == C)) && \"Expected icmp+shr simplify did not occur.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2237, __PRETTY_FUNCTION__));

// If the bits shifted out are known zero, compare the unshifted value:
//  (X & 4) >> 1 == 2  --> (X & 4) == 4.
if (Shr->isExact())
  return new ICmpInst(Pred, X, ConstantInt::get(ShrTy, C << ShAmtVal));

if (Shr->hasOneUse()) {
  // Canonicalize the shift into an 'and':
  // icmp eq/ne (shr X, ShAmt), C --> icmp eq/ne (and X, HiMask), (C << ShAmt)
  APInt Val(APInt::getHighBitsSet(TypeBits, TypeBits - ShAmtVal));
  Constant *Mask = ConstantInt::get(ShrTy, Val);
  Value *And = Builder.CreateAnd(X, Mask, Shr->getName() + ".mask");
  return new ICmpInst(Pred, And, ConstantInt::get(ShrTy, C << ShAmtVal));
}

return nullptr;
2254}

2256Instruction *InstCombiner::foldICmpSRemConstant(ICmpInst &Cmp,
                                              BinaryOperator *SRem,
                                              const APInt &C) {
// Match an 'is positive' or 'is negative' comparison of remainder by a
// constant power-of-2 value:
// (X % pow2C) sgt/slt 0
const ICmpInst::Predicate Pred = Cmp.getPredicate();
if (Pred != ICmpInst::ICMP_SGT && Pred != ICmpInst::ICMP_SLT)
  return nullptr;

// TODO: The one-use check is standard because we do not typically want to
//       create longer instruction sequences, but this might be a special-case
//       because srem is not good for analysis or codegen.
if (!SRem->hasOneUse())
  return nullptr;

const APInt *DivisorC;
if (!C.isNullValue() || !match(SRem->getOperand(1), m_Power2(DivisorC)))
  return nullptr;

// Mask off the sign bit and the modulo bits (low-bits).
Type *Ty = SRem->getType();
APInt SignMask = APInt::getSignMask(Ty->getScalarSizeInBits());
Constant *MaskC = ConstantInt::get(Ty, SignMask | (*DivisorC - 1));
Value *And = Builder.CreateAnd(SRem->getOperand(0), MaskC);

// For 'is positive?' check that the sign-bit is clear and at least 1 masked
// bit is set. Example:
// (i8 X % 32) s> 0 --> (X & 159) s> 0
if (Pred == ICmpInst::ICMP_SGT)
  return new ICmpInst(ICmpInst::ICMP_SGT, And, ConstantInt::getNullValue(Ty));

// For 'is negative?' check that the sign-bit is set and at least 1 masked
// bit is set. Example:
// (i16 X % 4) s< 0 --> (X & 32771) u> 32768
return new ICmpInst(ICmpInst::ICMP_UGT, And, ConstantInt::get(Ty, SignMask));
2292}

2294/// Fold icmp (udiv X, Y), C.
2295Instruction *InstCombiner::foldICmpUDivConstant(ICmpInst &Cmp,
                                              BinaryOperator *UDiv,
                                              const APInt &C) {
const APInt *C2;
if (!match(UDiv->getOperand(0), m_APInt(C2)))
  return nullptr;

assert(*C2 != 0 && "udiv 0, X should have been simplified already.")((*C2 != 0 && "udiv 0, X should have been simplified already."
) ? static_cast<void> (0) : __assert_fail ("*C2 != 0 && \"udiv 0, X should have been simplified already.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2302, __PRETTY_FUNCTION__));

// (icmp ugt (udiv C2, Y), C) -> (icmp ule Y, C2/(C+1))
Value *Y = UDiv->getOperand(1);
if (Cmp.getPredicate() == ICmpInst::ICMP_UGT) {
  assert(!C.isMaxValue() &&((!C.isMaxValue() && "icmp ugt X, UINT_MAX should have been simplified already."
) ? static_cast<void> (0) : __assert_fail ("!C.isMaxValue() && \"icmp ugt X, UINT_MAX should have been simplified already.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2308, __PRETTY_FUNCTION__))
         "icmp ugt X, UINT_MAX should have been simplified already.")((!C.isMaxValue() && "icmp ugt X, UINT_MAX should have been simplified already."
) ? static_cast<void> (0) : __assert_fail ("!C.isMaxValue() && \"icmp ugt X, UINT_MAX should have been simplified already.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2308, __PRETTY_FUNCTION__));
  return new ICmpInst(ICmpInst::ICMP_ULE, Y,
                      ConstantInt::get(Y->getType(), C2->udiv(C + 1)));
}

// (icmp ult (udiv C2, Y), C) -> (icmp ugt Y, C2/C)
if (Cmp.getPredicate() == ICmpInst::ICMP_ULT) {
  assert(C != 0 && "icmp ult X, 0 should have been simplified already.")((C != 0 && "icmp ult X, 0 should have been simplified already."
) ? static_cast<void> (0) : __assert_fail ("C != 0 && \"icmp ult X, 0 should have been simplified already.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2315, __PRETTY_FUNCTION__));
  return new ICmpInst(ICmpInst::ICMP_UGT, Y,
                      ConstantInt::get(Y->getType(), C2->udiv(C)));
}

return nullptr;
2321}

2323/// Fold icmp ({su}div X, Y), C.
2324Instruction *InstCombiner::foldICmpDivConstant(ICmpInst &Cmp,
                                             BinaryOperator *Div,
                                             const APInt &C) {
// Fold: icmp pred ([us]div X, C2), C -> range test
// Fold this div into the comparison, producing a range check.
// Determine, based on the divide type, what the range is being
// checked.  If there is an overflow on the low or high side, remember
// it, otherwise compute the range [low, hi) bounding the new value.
// See: InsertRangeTest above for the kinds of replacements possible.
const APInt *C2;
if (!match(Div->getOperand(1), m_APInt(C2)))
  return nullptr;

// FIXME: If the operand types don't match the type of the divide
// then don't attempt this transform. The code below doesn't have the
// logic to deal with a signed divide and an unsigned compare (and
// vice versa). This is because (x /s C2) <s C  produces different
// results than (x /s C2) <u C or (x /u C2) <s C or even
// (x /u C2) <u C.  Simply casting the operands and result won't
// work. :(  The if statement below tests that condition and bails
// if it finds it.
bool DivIsSigned = Div->getOpcode() == Instruction::SDiv;
if (!Cmp.isEquality() && DivIsSigned != Cmp.isSigned())
  return nullptr;

// The ProdOV computation fails on divide by 0 and divide by -1. Cases with
// INT_MIN will also fail if the divisor is 1. Although folds of all these
// division-by-constant cases should be present, we can not assert that they
// have happened before we reach this icmp instruction.
if (C2->isNullValue() || C2->isOneValue() ||
    (DivIsSigned && C2->isAllOnesValue()))
  return nullptr;

// Compute Prod = C * C2. We are essentially solving an equation of
// form X / C2 = C. We solve for X by multiplying C2 and C.
// By solving for X, we can turn this into a range check instead of computing
// a divide.
APInt Prod = C * *C2;

// Determine if the product overflows by seeing if the product is not equal to
// the divide. Make sure we do the same kind of divide as in the LHS
// instruction that we're folding.
bool ProdOV = (DivIsSigned ? Prod.sdiv(*C2) : Prod.udiv(*C2)) != C;

ICmpInst::Predicate Pred = Cmp.getPredicate();

// If the division is known to be exact, then there is no remainder from the
// divide, so the covered range size is unit, otherwise it is the divisor.
APInt RangeSize = Div->isExact() ? APInt(C2->getBitWidth(), 1) : *C2;

// Figure out the interval that is being checked.  For example, a comparison
// like "X /u 5 == 0" is really checking that X is in the interval [0, 5).
// Compute this interval based on the constants involved and the signedness of
// the compare/divide.  This computes a half-open interval, keeping track of
// whether either value in the interval overflows.  After analysis each
// overflow variable is set to 0 if it's corresponding bound variable is valid
// -1 if overflowed off the bottom end, or +1 if overflowed off the top end.
int LoOverflow = 0, HiOverflow = 0;
APInt LoBound, HiBound;

if (!DivIsSigned) {  // udiv
  // e.g. X/5 op 3  --> [15, 20)
  LoBound = Prod;
  HiOverflow = LoOverflow = ProdOV;
  if (!HiOverflow) {
    // If this is not an exact divide, then many values in the range collapse
    // to the same result value.
    HiOverflow = addWithOverflow(HiBound, LoBound, RangeSize, false);
  }
} else if (C2->isStrictlyPositive()) { // Divisor is > 0.
  if (C.isNullValue()) {       // (X / pos) op 0
    // Can't overflow.  e.g.  X/2 op 0 --> [-1, 2)
    LoBound = -(RangeSize - 1);
    HiBound = RangeSize;
  } else if (C.isStrictlyPositive()) {   // (X / pos) op pos
    LoBound = Prod;     // e.g.   X/5 op 3 --> [15, 20)
    HiOverflow = LoOverflow = ProdOV;
    if (!HiOverflow)
      HiOverflow = addWithOverflow(HiBound, Prod, RangeSize, true);
  } else {                       // (X / pos) op neg
    // e.g. X/5 op -3  --> [-15-4, -15+1) --> [-19, -14)
    HiBound = Prod + 1;
    LoOverflow = HiOverflow = ProdOV ? -1 : 0;
    if (!LoOverflow) {
      APInt DivNeg = -RangeSize;
      LoOverflow = addWithOverflow(LoBound, HiBound, DivNeg, true) ? -1 : 0;
    }
  }
} else if (C2->isNegative()) { // Divisor is < 0.
  if (Div->isExact())
    RangeSize.negate();
  if (C.isNullValue()) { // (X / neg) op 0
    // e.g. X/-5 op 0  --> [-4, 5)
    LoBound = RangeSize + 1;
    HiBound = -RangeSize;
    if (HiBound == *C2) {        // -INTMIN = INTMIN
      HiOverflow = 1;            // [INTMIN+1, overflow)
      HiBound = APInt();         // e.g. X/INTMIN = 0 --> X > INTMIN
    }
  } else if (C.isStrictlyPositive()) {   // (X / neg) op pos
    // e.g. X/-5 op 3  --> [-19, -14)
    HiBound = Prod + 1;
    HiOverflow = LoOverflow = ProdOV ? -1 : 0;
    if (!LoOverflow)
      LoOverflow = addWithOverflow(LoBound, HiBound, RangeSize, true) ? -1:0;
  } else {                       // (X / neg) op neg
    LoBound = Prod;       // e.g. X/-5 op -3  --> [15, 20)
    LoOverflow = HiOverflow = ProdOV;
    if (!HiOverflow)
      HiOverflow = subWithOverflow(HiBound, Prod, RangeSize, true);
  }

  // Dividing by a negative swaps the condition.  LT <-> GT
  Pred = ICmpInst::getSwappedPredicate(Pred);
}

Value *X = Div->getOperand(0);
switch (Pred) {
  default: llvm_unreachable("Unhandled icmp opcode!")::llvm::llvm_unreachable_internal("Unhandled icmp opcode!", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2442);
  case ICmpInst::ICMP_EQ:
    if (LoOverflow && HiOverflow)
      return replaceInstUsesWith(Cmp, Builder.getFalse());
    if (HiOverflow)
      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE :
                          ICmpInst::ICMP_UGE, X,
                          ConstantInt::get(Div->getType(), LoBound));
    if (LoOverflow)
      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT :
                          ICmpInst::ICMP_ULT, X,
                          ConstantInt::get(Div->getType(), HiBound));
    return replaceInstUsesWith(
        Cmp, insertRangeTest(X, LoBound, HiBound, DivIsSigned, true));
  case ICmpInst::ICMP_NE:
    if (LoOverflow && HiOverflow)
      return replaceInstUsesWith(Cmp, Builder.getTrue());
    if (HiOverflow)
      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT :
                          ICmpInst::ICMP_ULT, X,
                          ConstantInt::get(Div->getType(), LoBound));
    if (LoOverflow)
      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE :
                          ICmpInst::ICMP_UGE, X,
                          ConstantInt::get(Div->getType(), HiBound));
    return replaceInstUsesWith(Cmp,
                               insertRangeTest(X, LoBound, HiBound,
                                               DivIsSigned, false));
  case ICmpInst::ICMP_ULT:
  case ICmpInst::ICMP_SLT:
    if (LoOverflow == +1)   // Low bound is greater than input range.
      return replaceInstUsesWith(Cmp, Builder.getTrue());
    if (LoOverflow == -1)   // Low bound is less than input range.
      return replaceInstUsesWith(Cmp, Builder.getFalse());
    return new ICmpInst(Pred, X, ConstantInt::get(Div->getType(), LoBound));
  case ICmpInst::ICMP_UGT:
  case ICmpInst::ICMP_SGT:
    if (HiOverflow == +1)       // High bound greater than input range.
      return replaceInstUsesWith(Cmp, Builder.getFalse());
    if (HiOverflow == -1)       // High bound less than input range.
      return replaceInstUsesWith(Cmp, Builder.getTrue());
    if (Pred == ICmpInst::ICMP_UGT)
      return new ICmpInst(ICmpInst::ICMP_UGE, X,
                          ConstantInt::get(Div->getType(), HiBound));
    return new ICmpInst(ICmpInst::ICMP_SGE, X,
                        ConstantInt::get(Div->getType(), HiBound));
}

return nullptr;
2491}

2493/// Fold icmp (sub X, Y), C.
2494Instruction *InstCombiner::foldICmpSubConstant(ICmpInst &Cmp,
                                             BinaryOperator *Sub,
                                             const APInt &C) {
Value *X = Sub->getOperand(0), *Y = Sub->getOperand(1);
ICmpInst::Predicate Pred = Cmp.getPredicate();
const APInt *C2;
APInt SubResult;

// icmp eq/ne (sub C, Y), C -> icmp eq/ne Y, 0
if (match(X, m_APInt(C2)) && *C2 == C && Cmp.isEquality())
  return new ICmpInst(Cmp.getPredicate(), Y,
                      ConstantInt::get(Y->getType(), 0));

// (icmp P (sub nuw|nsw C2, Y), C) -> (icmp swap(P) Y, C2-C)
if (match(X, m_APInt(C2)) &&
    ((Cmp.isUnsigned() && Sub->hasNoUnsignedWrap()) ||
     (Cmp.isSigned() && Sub->hasNoSignedWrap())) &&
    !subWithOverflow(SubResult, *C2, C, Cmp.isSigned()))
  return new ICmpInst(Cmp.getSwappedPredicate(), Y,
                      ConstantInt::get(Y->getType(), SubResult));

// The following transforms are only worth it if the only user of the subtract
// is the icmp.
if (!Sub->hasOneUse())
  return nullptr;

if (Sub->hasNoSignedWrap()) {
  // (icmp sgt (sub nsw X, Y), -1) -> (icmp sge X, Y)
  if (Pred == ICmpInst::ICMP_SGT && C.isAllOnesValue())
    return new ICmpInst(ICmpInst::ICMP_SGE, X, Y);

  // (icmp sgt (sub nsw X, Y), 0) -> (icmp sgt X, Y)
  if (Pred == ICmpInst::ICMP_SGT && C.isNullValue())
    return new ICmpInst(ICmpInst::ICMP_SGT, X, Y);

  // (icmp slt (sub nsw X, Y), 0) -> (icmp slt X, Y)
  if (Pred == ICmpInst::ICMP_SLT && C.isNullValue())
    return new ICmpInst(ICmpInst::ICMP_SLT, X, Y);

  // (icmp slt (sub nsw X, Y), 1) -> (icmp sle X, Y)
  if (Pred == ICmpInst::ICMP_SLT && C.isOneValue())
    return new ICmpInst(ICmpInst::ICMP_SLE, X, Y);
}

if (!match(X, m_APInt(C2)))
  return nullptr;

// C2 - Y <u C -> (Y | (C - 1)) == C2
//   iff (C2 & (C - 1)) == C - 1 and C is a power of 2
if (Pred == ICmpInst::ICMP_ULT && C.isPowerOf2() &&
    (*C2 & (C - 1)) == (C - 1))
  return new ICmpInst(ICmpInst::ICMP_EQ, Builder.CreateOr(Y, C - 1), X);

// C2 - Y >u C -> (Y | C) != C2
//   iff C2 & C == C and C + 1 is a power of 2
if (Pred == ICmpInst::ICMP_UGT && (C + 1).isPowerOf2() && (*C2 & C) == C)
  return new ICmpInst(ICmpInst::ICMP_NE, Builder.CreateOr(Y, C), X);

return nullptr;
2553}

2555/// Fold icmp (add X, Y), C.
2556Instruction *InstCombiner::foldICmpAddConstant(ICmpInst &Cmp,
                                             BinaryOperator *Add,
                                             const APInt &C) {
Value *Y = Add->getOperand(1);
const APInt *C2;
if (Cmp.isEquality() || !match(Y, m_APInt(C2)))
  return nullptr;

// Fold icmp pred (add X, C2), C.
Value *X = Add->getOperand(0);
Type *Ty = Add->getType();
CmpInst::Predicate Pred = Cmp.getPredicate();

// If the add does not wrap, we can always adjust the compare by subtracting
// the constants. Equality comparisons are handled elsewhere. SGE/SLE/UGE/ULE
// are canonicalized to SGT/SLT/UGT/ULT.
if ((Add->hasNoSignedWrap() &&
     (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLT)) ||
    (Add->hasNoUnsignedWrap() &&
     (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_ULT))) {
  bool Overflow;
  APInt NewC =
      Cmp.isSigned() ? C.ssub_ov(*C2, Overflow) : C.usub_ov(*C2, Overflow);
  // If there is overflow, the result must be true or false.
  // TODO: Can we assert there is no overflow because InstSimplify always
  // handles those cases?
  if (!Overflow)
    // icmp Pred (add nsw X, C2), C --> icmp Pred X, (C - C2)
    return new ICmpInst(Pred, X, ConstantInt::get(Ty, NewC));
}

auto CR = ConstantRange::makeExactICmpRegion(Pred, C).subtract(*C2);
const APInt &Upper = CR.getUpper();
const APInt &Lower = CR.getLower();
if (Cmp.isSigned()) {
  if (Lower.isSignMask())
    return new ICmpInst(ICmpInst::ICMP_SLT, X, ConstantInt::get(Ty, Upper));
  if (Upper.isSignMask())
    return new ICmpInst(ICmpInst::ICMP_SGE, X, ConstantInt::get(Ty, Lower));
} else {
  if (Lower.isMinValue())
    return new ICmpInst(ICmpInst::ICMP_ULT, X, ConstantInt::get(Ty, Upper));
  if (Upper.isMinValue())
    return new ICmpInst(ICmpInst::ICMP_UGE, X, ConstantInt::get(Ty, Lower));
}

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

// X+C <u C2 -> (X & -C2) == C
//   iff C & (C2-1) == 0
//       C2 is a power of 2
if (Pred == ICmpInst::ICMP_ULT && C.isPowerOf2() && (*C2 & (C - 1)) == 0)
  return new ICmpInst(ICmpInst::ICMP_EQ, Builder.CreateAnd(X, -C),
                      ConstantExpr::getNeg(cast<Constant>(Y)));

// X+C >u C2 -> (X & ~C2) != C
//   iff C & C2 == 0
//       C2+1 is a power of 2
if (Pred == ICmpInst::ICMP_UGT && (C + 1).isPowerOf2() && (*C2 & C) == 0)
  return new ICmpInst(ICmpInst::ICMP_NE, Builder.CreateAnd(X, ~C),
                      ConstantExpr::getNeg(cast<Constant>(Y)));

return nullptr;
2620}

2622bool InstCombiner::matchThreeWayIntCompare(SelectInst *SI, Value *&LHS,
                                         Value *&RHS, ConstantInt *&Less,
                                         ConstantInt *&Equal,
                                         ConstantInt *&Greater) {
// TODO: Generalize this to work with other comparison idioms or ensure
// they get canonicalized into this form.

// select i1 (a == b),
//        i32 Equal,
//        i32 (select i1 (a < b), i32 Less, i32 Greater)
// where Equal, Less and Greater are placeholders for any three constants.
ICmpInst::Predicate PredA;
if (!match(SI->getCondition(), m_ICmp(PredA, m_Value(LHS), m_Value(RHS))) ||
    !ICmpInst::isEquality(PredA))
  return false;
Value *EqualVal = SI->getTrueValue();
Value *UnequalVal = SI->getFalseValue();
// We still can get non-canonical predicate here, so canonicalize.
if (PredA == ICmpInst::ICMP_NE)
  std::swap(EqualVal, UnequalVal);
if (!match(EqualVal, m_ConstantInt(Equal)))
  return false;
ICmpInst::Predicate PredB;
Value *LHS2, *RHS2;
if (!match(UnequalVal, m_Select(m_ICmp(PredB, m_Value(LHS2), m_Value(RHS2)),
                                m_ConstantInt(Less), m_ConstantInt(Greater))))
  return false;
// We can get predicate mismatch here, so canonicalize if possible:
// First, ensure that 'LHS' match.
if (LHS2 != LHS) {
  // x sgt y <--> y slt x
  std::swap(LHS2, RHS2);
  PredB = ICmpInst::getSwappedPredicate(PredB);
}
if (LHS2 != LHS)
  return false;
// We also need to canonicalize 'RHS'.
if (PredB == ICmpInst::ICMP_SGT && isa<Constant>(RHS2)) {
  // x sgt C-1  <-->  x sge C  <-->  not(x slt C)
  auto FlippedStrictness =
      getFlippedStrictnessPredicateAndConstant(PredB, cast<Constant>(RHS2));
  if (!FlippedStrictness)
    return false;
  assert(FlippedStrictness->first == ICmpInst::ICMP_SGE && "Sanity check")((FlippedStrictness->first == ICmpInst::ICMP_SGE &&
 "Sanity check") ? static_cast<void> (0) : __assert_fail
 ("FlippedStrictness->first == ICmpInst::ICMP_SGE && \"Sanity check\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2665, __PRETTY_FUNCTION__));
  RHS2 = FlippedStrictness->second;
  // And kind-of perform the result swap.
  std::swap(Less, Greater);
  PredB = ICmpInst::ICMP_SLT;
}
return PredB == ICmpInst::ICMP_SLT && RHS == RHS2;
2672}

2674Instruction *InstCombiner::foldICmpSelectConstant(ICmpInst &Cmp,
                                                SelectInst *Select,
                                                ConstantInt *C) {

assert(C && "Cmp RHS should be a constant int!")((C && "Cmp RHS should be a constant int!") ? static_cast
<void> (0) : __assert_fail ("C && \"Cmp RHS should be a constant int!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2678, __PRETTY_FUNCTION__));
// If we're testing a constant value against the result of a three way
// comparison, the result can be expressed directly in terms of the
// original values being compared.  Note: We could possibly be more
// aggressive here and remove the hasOneUse test. The original select is
// really likely to simplify or sink when we remove a test of the result.
Value *OrigLHS, *OrigRHS;
ConstantInt *C1LessThan, *C2Equal, *C3GreaterThan;
if (Cmp.hasOneUse() &&
    matchThreeWayIntCompare(Select, OrigLHS, OrigRHS, C1LessThan, C2Equal,
                            C3GreaterThan)) {
  assert(C1LessThan && C2Equal && C3GreaterThan)((C1LessThan && C2Equal && C3GreaterThan) ? static_cast
<void> (0) : __assert_fail ("C1LessThan && C2Equal && C3GreaterThan"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2689, __PRETTY_FUNCTION__));

  bool TrueWhenLessThan =
      ConstantExpr::getCompare(Cmp.getPredicate(), C1LessThan, C)
          ->isAllOnesValue();
  bool TrueWhenEqual =
      ConstantExpr::getCompare(Cmp.getPredicate(), C2Equal, C)
          ->isAllOnesValue();
  bool TrueWhenGreaterThan =
      ConstantExpr::getCompare(Cmp.getPredicate(), C3GreaterThan, C)
          ->isAllOnesValue();

  // This generates the new instruction that will replace the original Cmp
  // Instruction. Instead of enumerating the various combinations when
  // TrueWhenLessThan, TrueWhenEqual and TrueWhenGreaterThan are true versus
  // false, we rely on chaining of ORs and future passes of InstCombine to
  // simplify the OR further (i.e. a s< b || a == b becomes a s<= b).

  // When none of the three constants satisfy the predicate for the RHS (C),
  // the entire original Cmp can be simplified to a false.
  Value *Cond = Builder.getFalse();
  if (TrueWhenLessThan)
    Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_SLT,
                                                     OrigLHS, OrigRHS));
  if (TrueWhenEqual)
    Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_EQ,
                                                     OrigLHS, OrigRHS));
  if (TrueWhenGreaterThan)
    Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_SGT,
                                                     OrigLHS, OrigRHS));

  return replaceInstUsesWith(Cmp, Cond);
}
return nullptr;
2723}

2725static Instruction *foldICmpBitCast(ICmpInst &Cmp,
                                  InstCombiner::BuilderTy &Builder) {
auto *Bitcast = dyn_cast<BitCastInst>(Cmp.getOperand(0));
if (!Bitcast)
  return nullptr;

ICmpInst::Predicate Pred = Cmp.getPredicate();
Value *Op1 = Cmp.getOperand(1);
Value *BCSrcOp = Bitcast->getOperand(0);

// Make sure the bitcast doesn't change the number of vector elements.
if (Bitcast->getSrcTy()->getScalarSizeInBits() ==
        Bitcast->getDestTy()->getScalarSizeInBits()) {
  // Zero-equality and sign-bit checks are preserved through sitofp + bitcast.
  Value *X;
  if (match(BCSrcOp, m_SIToFP(m_Value(X)))) {
    // icmp  eq (bitcast (sitofp X)), 0 --> icmp  eq X, 0
    // icmp  ne (bitcast (sitofp X)), 0 --> icmp  ne X, 0
    // icmp slt (bitcast (sitofp X)), 0 --> icmp slt X, 0
    // icmp sgt (bitcast (sitofp X)), 0 --> icmp sgt X, 0
    if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_SLT ||
         Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT) &&
        match(Op1, m_Zero()))
      return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));

    // icmp slt (bitcast (sitofp X)), 1 --> icmp slt X, 1
    if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_One()))
      return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), 1));

    // icmp sgt (bitcast (sitofp X)), -1 --> icmp sgt X, -1
    if (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes()))
      return new ICmpInst(Pred, X,
                          ConstantInt::getAllOnesValue(X->getType()));
  }

  // Zero-equality checks are preserved through unsigned floating-point casts:
  // icmp eq (bitcast (uitofp X)), 0 --> icmp eq X, 0
  // icmp ne (bitcast (uitofp X)), 0 --> icmp ne X, 0
  if (match(BCSrcOp, m_UIToFP(m_Value(X))))
    if (Cmp.isEquality() && match(Op1, m_Zero()))
      return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
}

// Test to see if the operands of the icmp are casted versions of other
// values. If the ptr->ptr cast can be stripped off both arguments, do so.
if (Bitcast->getType()->isPointerTy() &&
    (isa<Constant>(Op1) || isa<BitCastInst>(Op1))) {
  // If operand #1 is a bitcast instruction, it must also be a ptr->ptr cast
  // so eliminate it as well.
  if (auto *BC2 = dyn_cast<BitCastInst>(Op1))
    Op1 = BC2->getOperand(0);

  Op1 = Builder.CreateBitCast(Op1, BCSrcOp->getType());
  return new ICmpInst(Pred, BCSrcOp, Op1);
}

// Folding: icmp <pred> iN X, C
//  where X = bitcast <M x iK> (shufflevector <M x iK> %vec, undef, SC)) to iN
//    and C is a splat of a K-bit pattern
//    and SC is a constant vector = <C', C', C', ..., C'>
// Into:
//   %E = extractelement <M x iK> %vec, i32 C'
//   icmp <pred> iK %E, trunc(C)
const APInt *C;
if (!match(Cmp.getOperand(1), m_APInt(C)) ||
    !Bitcast->getType()->isIntegerTy() ||
    !Bitcast->getSrcTy()->isIntOrIntVectorTy())
  return nullptr;

Value *Vec;
Constant *Mask;
if (match(BCSrcOp,
          m_ShuffleVector(m_Value(Vec), m_Undef(), m_Constant(Mask)))) {
  // Check whether every element of Mask is the same constant
  if (auto *Elem = dyn_cast_or_null<ConstantInt>(Mask->getSplatValue())) {
    auto *VecTy = cast<VectorType>(BCSrcOp->getType());
    auto *EltTy = cast<IntegerType>(VecTy->getElementType());
    if (C->isSplat(EltTy->getBitWidth())) {
      // Fold the icmp based on the value of C
      // If C is M copies of an iK sized bit pattern,
      // then:
      //   =>  %E = extractelement <N x iK> %vec, i32 Elem
      //       icmp <pred> iK %SplatVal, <pattern>
      Value *Extract = Builder.CreateExtractElement(Vec, Elem);
      Value *NewC = ConstantInt::get(EltTy, C->trunc(EltTy->getBitWidth()));
      return new ICmpInst(Pred, Extract, NewC);
    }
  }
}
return nullptr;
2815}

2817/// Try to fold integer comparisons with a constant operand: icmp Pred X, C
2818/// where X is some kind of instruction.
2819Instruction *InstCombiner::foldICmpInstWithConstant(ICmpInst &Cmp) {
const APInt *C;
if (!match(Cmp.getOperand(1), m_APInt(C)))
  return nullptr;

if (auto *BO = dyn_cast<BinaryOperator>(Cmp.getOperand(0))) {
  switch (BO->getOpcode()) {
  case Instruction::Xor:
    if (Instruction *I = foldICmpXorConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::And:
    if (Instruction *I = foldICmpAndConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::Or:
    if (Instruction *I = foldICmpOrConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::Mul:
    if (Instruction *I = foldICmpMulConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::Shl:
    if (Instruction *I = foldICmpShlConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::LShr:
  case Instruction::AShr:
    if (Instruction *I = foldICmpShrConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::SRem:
    if (Instruction *I = foldICmpSRemConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::UDiv:
    if (Instruction *I = foldICmpUDivConstant(Cmp, BO, *C))
      return I;
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case Instruction::SDiv:
    if (Instruction *I = foldICmpDivConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::Sub:
    if (Instruction *I = foldICmpSubConstant(Cmp, BO, *C))
      return I;
    break;
  case Instruction::Add:
    if (Instruction *I = foldICmpAddConstant(Cmp, BO, *C))
      return I;
    break;
  default:
    break;
  }
  // TODO: These folds could be refactored to be part of the above calls.
  if (Instruction *I = foldICmpBinOpEqualityWithConstant(Cmp, BO, *C))
    return I;
}

// Match against CmpInst LHS being instructions other than binary operators.

if (auto *SI = dyn_cast<SelectInst>(Cmp.getOperand(0))) {
  // For now, we only support constant integers while folding the
  // ICMP(SELECT)) pattern. We can extend this to support vector of integers
  // similar to the cases handled by binary ops above.
  if (ConstantInt *ConstRHS = dyn_cast<ConstantInt>(Cmp.getOperand(1)))
    if (Instruction *I = foldICmpSelectConstant(Cmp, SI, ConstRHS))
      return I;
}

if (auto *TI = dyn_cast<TruncInst>(Cmp.getOperand(0))) {
  if (Instruction *I = foldICmpTruncConstant(Cmp, TI, *C))
    return I;
}

if (auto *II = dyn_cast<IntrinsicInst>(Cmp.getOperand(0)))
  if (Instruction *I = foldICmpIntrinsicWithConstant(Cmp, II, *C))
    return I;

return nullptr;
2900}

2902/// Fold an icmp equality instruction with binary operator LHS and constant RHS:
2903/// icmp eq/ne BO, C.
2904Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
                                                           BinaryOperator *BO,
                                                           const APInt &C) {
// TODO: Some of these folds could work with arbitrary constants, but this
// function is limited to scalar and vector splat constants.
if (!Cmp.isEquality())
  return nullptr;

ICmpInst::Predicate Pred = Cmp.getPredicate();
bool isICMP_NE = Pred == ICmpInst::ICMP_NE;
Constant *RHS = cast<Constant>(Cmp.getOperand(1));
Value *BOp0 = BO->getOperand(0), *BOp1 = BO->getOperand(1);

switch (BO->getOpcode()) {
case Instruction::SRem:
  // If we have a signed (X % (2^c)) == 0, turn it into an unsigned one.
  if (C.isNullValue() && BO->hasOneUse()) {
    const APInt *BOC;
    if (match(BOp1, m_APInt(BOC)) && BOC->sgt(1) && BOC->isPowerOf2()) {
      Value *NewRem = Builder.CreateURem(BOp0, BOp1, BO->getName());
      return new ICmpInst(Pred, NewRem,
                          Constant::getNullValue(BO->getType()));
    }
  }
  break;
case Instruction::Add: {
  // Replace ((add A, B) != C) with (A != C-B) if B & C are constants.
  const APInt *BOC;
  if (match(BOp1, m_APInt(BOC))) {
    if (BO->hasOneUse()) {
      Constant *SubC = ConstantExpr::getSub(RHS, cast<Constant>(BOp1));
      return new ICmpInst(Pred, BOp0, SubC);
    }
  } else if (C.isNullValue()) {
    // Replace ((add A, B) != 0) with (A != -B) if A or B is
    // efficiently invertible, or if the add has just this one use.
    if (Value *NegVal = dyn_castNegVal(BOp1))
      return new ICmpInst(Pred, BOp0, NegVal);
    if (Value *NegVal = dyn_castNegVal(BOp0))
      return new ICmpInst(Pred, NegVal, BOp1);
    if (BO->hasOneUse()) {
      Value *Neg = Builder.CreateNeg(BOp1);
      Neg->takeName(BO);
      return new ICmpInst(Pred, BOp0, Neg);
    }
  }
  break;
}
case Instruction::Xor:
  if (BO->hasOneUse()) {
    if (Constant *BOC = dyn_cast<Constant>(BOp1)) {
      // For the xor case, we can xor two constants together, eliminating
      // the explicit xor.
      return new ICmpInst(Pred, BOp0, ConstantExpr::getXor(RHS, BOC));
    } else if (C.isNullValue()) {
      // Replace ((xor A, B) != 0) with (A != B)
      return new ICmpInst(Pred, BOp0, BOp1);
    }
  }
  break;
case Instruction::Sub:
  if (BO->hasOneUse()) {
    const APInt *BOC;
    if (match(BOp0, m_APInt(BOC))) {
      // Replace ((sub BOC, B) != C) with (B != BOC-C).
      Constant *SubC = ConstantExpr::getSub(cast<Constant>(BOp0), RHS);
      return new ICmpInst(Pred, BOp1, SubC);
    } else if (C.isNullValue()) {
      // Replace ((sub A, B) != 0) with (A != B).
      return new ICmpInst(Pred, BOp0, BOp1);
    }
  }
  break;
case Instruction::Or: {
  const APInt *BOC;
  if (match(BOp1, m_APInt(BOC)) && BO->hasOneUse() && RHS->isAllOnesValue()) {
    // Comparing if all bits outside of a constant mask are set?
    // Replace (X | C) == -1 with (X & ~C) == ~C.
    // This removes the -1 constant.
    Constant *NotBOC = ConstantExpr::getNot(cast<Constant>(BOp1));
    Value *And = Builder.CreateAnd(BOp0, NotBOC);
    return new ICmpInst(Pred, And, NotBOC);
  }
  break;
}
case Instruction::And: {
  const APInt *BOC;
  if (match(BOp1, m_APInt(BOC))) {
    // If we have ((X & C) == C), turn it into ((X & C) != 0).
    if (C == *BOC && C.isPowerOf2())
      return new ICmpInst(isICMP_NE ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE,
                          BO, Constant::getNullValue(RHS->getType()));
  }
  break;
}
case Instruction::Mul:
  if (C.isNullValue() && BO->hasNoSignedWrap()) {
    const APInt *BOC;
    if (match(BOp1, m_APInt(BOC)) && !BOC->isNullValue()) {
      // The trivial case (mul X, 0) is handled by InstSimplify.
      // General case : (mul X, C) != 0 iff X != 0
      //                (mul X, C) == 0 iff X == 0
      return new ICmpInst(Pred, BOp0, Constant::getNullValue(RHS->getType()));
    }
  }
  break;
case Instruction::UDiv:
  if (C.isNullValue()) {
    // (icmp eq/ne (udiv A, B), 0) -> (icmp ugt/ule i32 B, A)
    auto NewPred = isICMP_NE ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_UGT;
    return new ICmpInst(NewPred, BOp1, BOp0);
  }
  break;
default:
  break;
}
return nullptr;
3021}

3023/// Fold an equality icmp with LLVM intrinsic and constant operand.
3024Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp,
                                                         IntrinsicInst *II,
                                                         const APInt &C) {
Type *Ty = II->getType();
unsigned BitWidth = C.getBitWidth();
switch (II->getIntrinsicID()) {
case Intrinsic::bswap:
  Worklist.Add(II);
  Cmp.setOperand(0, II->getArgOperand(0));
  Cmp.setOperand(1, ConstantInt::get(Ty, C.byteSwap()));
  return &Cmp;

case Intrinsic::ctlz:
case Intrinsic::cttz: {
  // ctz(A) == bitwidth(A)  ->  A == 0 and likewise for !=
  if (C == BitWidth) {
    Worklist.Add(II);
    Cmp.setOperand(0, II->getArgOperand(0));
    Cmp.setOperand(1, ConstantInt::getNullValue(Ty));
    return &Cmp;
  }

  // ctz(A) == C -> A & Mask1 == Mask2, where Mask2 only has bit C set
  // and Mask1 has bits 0..C+1 set. Similar for ctl, but for high bits.
  // Limit to one use to ensure we don't increase instruction count.
  unsigned Num = C.getLimitedValue(BitWidth);
  if (Num != BitWidth && II->hasOneUse()) {
    bool IsTrailing = II->getIntrinsicID() == Intrinsic::cttz;
    APInt Mask1 = IsTrailing ? APInt::getLowBitsSet(BitWidth, Num + 1)
                             : APInt::getHighBitsSet(BitWidth, Num + 1);
    APInt Mask2 = IsTrailing
      ? APInt::getOneBitSet(BitWidth, Num)
      : APInt::getOneBitSet(BitWidth, BitWidth - Num - 1);
    Cmp.setOperand(0, Builder.CreateAnd(II->getArgOperand(0), Mask1));
    Cmp.setOperand(1, ConstantInt::get(Ty, Mask2));
    Worklist.Add(II);
    return &Cmp;
  }
  break;
}

case Intrinsic::ctpop: {
  // popcount(A) == 0  ->  A == 0 and likewise for !=
  // popcount(A) == bitwidth(A)  ->  A == -1 and likewise for !=
  bool IsZero = C.isNullValue();
  if (IsZero || C == BitWidth) {
    Worklist.Add(II);
    Cmp.setOperand(0, II->getArgOperand(0));
    auto *NewOp =
        IsZero ? Constant::getNullValue(Ty) : Constant::getAllOnesValue(Ty);
    Cmp.setOperand(1, NewOp);
    return &Cmp;
  }
  break;
}

case Intrinsic::uadd_sat: {
  // uadd.sat(a, b) == 0  ->  (a | b) == 0
  if (C.isNullValue()) {
    Value *Or = Builder.CreateOr(II->getArgOperand(0), II->getArgOperand(1));
    return replaceInstUsesWith(Cmp, Builder.CreateICmp(
        Cmp.getPredicate(), Or, Constant::getNullValue(Ty)));

  }
  break;
}

case Intrinsic::usub_sat: {
  // usub.sat(a, b) == 0  ->  a <= b
  if (C.isNullValue()) {
    ICmpInst::Predicate NewPred = Cmp.getPredicate() == ICmpInst::ICMP_EQ
        ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_UGT;
    return ICmpInst::Create(Instruction::ICmp, NewPred,
                            II->getArgOperand(0), II->getArgOperand(1));
  }
  break;
}
default:
  break;
}

return nullptr;
3106}

3108/// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
3109Instruction *InstCombiner::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
                                                       IntrinsicInst *II,
                                                       const APInt &C) {
if (Cmp.isEquality())
  return foldICmpEqIntrinsicWithConstant(Cmp, II, C);

Type *Ty = II->getType();
unsigned BitWidth = C.getBitWidth();
switch (II->getIntrinsicID()) {
case Intrinsic::ctlz: {
  // ctlz(0bXXXXXXXX) > 3 -> 0bXXXXXXXX < 0b00010000
  if (Cmp.getPredicate() == ICmpInst::ICMP_UGT && C.ult(BitWidth)) {
    unsigned Num = C.getLimitedValue();
    APInt Limit = APInt::getOneBitSet(BitWidth, BitWidth - Num - 1);
    return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_ULT,
                           II->getArgOperand(0), ConstantInt::get(Ty, Limit));
  }

  // ctlz(0bXXXXXXXX) < 3 -> 0bXXXXXXXX > 0b00011111
  if (Cmp.getPredicate() == ICmpInst::ICMP_ULT &&
      C.uge(1) && C.ule(BitWidth)) {
    unsigned Num = C.getLimitedValue();
    APInt Limit = APInt::getLowBitsSet(BitWidth, BitWidth - Num);
    return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_UGT,
                           II->getArgOperand(0), ConstantInt::get(Ty, Limit));
  }
  break;
}
case Intrinsic::cttz: {
  // Limit to one use to ensure we don't increase instruction count.
  if (!II->hasOneUse())
    return nullptr;

  // cttz(0bXXXXXXXX) > 3 -> 0bXXXXXXXX & 0b00001111 == 0
  if (Cmp.getPredicate() == ICmpInst::ICMP_UGT && C.ult(BitWidth)) {
    APInt Mask = APInt::getLowBitsSet(BitWidth, C.getLimitedValue() + 1);
    return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_EQ,
                           Builder.CreateAnd(II->getArgOperand(0), Mask),
                           ConstantInt::getNullValue(Ty));
  }

  // cttz(0bXXXXXXXX) < 3 -> 0bXXXXXXXX & 0b00000111 != 0
  if (Cmp.getPredicate() == ICmpInst::ICMP_ULT &&
      C.uge(1) && C.ule(BitWidth)) {
    APInt Mask = APInt::getLowBitsSet(BitWidth, C.getLimitedValue());
    return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_NE,
                           Builder.CreateAnd(II->getArgOperand(0), Mask),
                           ConstantInt::getNullValue(Ty));
  }
  break;
}
default:
  break;
}

return nullptr;
3165}

3167/// Handle icmp with constant (but not simple integer constant) RHS.
3168Instruction *InstCombiner::foldICmpInstWithConstantNotInt(ICmpInst &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Constant *RHSC = dyn_cast<Constant>(Op1);
Instruction *LHSI = dyn_cast<Instruction>(Op0);
if (!RHSC || !LHSI)
  return nullptr;

switch (LHSI->getOpcode()) {
case Instruction::GetElementPtr:
  // icmp pred GEP (P, int 0, int 0, int 0), null -> icmp pred P, null
  if (RHSC->isNullValue() &&
      cast<GetElementPtrInst>(LHSI)->hasAllZeroIndices())
    return new ICmpInst(
        I.getPredicate(), LHSI->getOperand(0),
        Constant::getNullValue(LHSI->getOperand(0)->getType()));
  break;
case Instruction::PHI:
  // Only fold icmp into the PHI if the phi and icmp are in the same
  // block.  If in the same block, we're encouraging jump threading.  If
  // not, we are just pessimizing the code by making an i1 phi.
  if (LHSI->getParent() == I.getParent())
    if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
      return NV;
  break;
case Instruction::Select: {
  // If either operand of the select is a constant, we can fold the
  // comparison into the select arms, which will cause one to be
  // constant folded and the select turned into a bitwise or.
  Value *Op1 = nullptr, *Op2 = nullptr;
  ConstantInt *CI = nullptr;
  if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(1))) {
    Op1 = ConstantExpr::getICmp(I.getPredicate(), C, RHSC);
    CI = dyn_cast<ConstantInt>(Op1);
  }
  if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(2))) {
    Op2 = ConstantExpr::getICmp(I.getPredicate(), C, RHSC);
    CI = dyn_cast<ConstantInt>(Op2);
  }

  // We only want to perform this transformation if it will not lead to
  // additional code. This is true if either both sides of the select
  // fold to a constant (in which case the icmp is replaced with a select
  // which will usually simplify) or this is the only user of the
  // select (in which case we are trading a select+icmp for a simpler
  // select+icmp) or all uses of the select can be replaced based on
  // dominance information ("Global cases").
  bool Transform = false;
  if (Op1 && Op2)
    Transform = true;
  else if (Op1 || Op2) {
    // Local case
    if (LHSI->hasOneUse())
      Transform = true;
    // Global cases
    else if (CI && !CI->isZero())
      // When Op1 is constant try replacing select with second operand.
      // Otherwise Op2 is constant and try replacing select with first
      // operand.
      Transform =
          replacedSelectWithOperand(cast<SelectInst>(LHSI), &I, Op1 ? 2 : 1);
  }
  if (Transform) {
    if (!Op1)
      Op1 = Builder.CreateICmp(I.getPredicate(), LHSI->getOperand(1), RHSC,
                               I.getName());
    if (!Op2)
      Op2 = Builder.CreateICmp(I.getPredicate(), LHSI->getOperand(2), RHSC,
                               I.getName());
    return SelectInst::Create(LHSI->getOperand(0), Op1, Op2);
  }
  break;
}
case Instruction::IntToPtr:
  // icmp pred inttoptr(X), null -> icmp pred X, 0
  if (RHSC->isNullValue() &&
      DL.getIntPtrType(RHSC->getType()) == LHSI->getOperand(0)->getType())
    return new ICmpInst(
        I.getPredicate(), LHSI->getOperand(0),
        Constant::getNullValue(LHSI->getOperand(0)->getType()));
  break;

case Instruction::Load:
  // Try to optimize things like "A[i] > 4" to index computations.
  if (GetElementPtrInst *GEP =
          dyn_cast<GetElementPtrInst>(LHSI->getOperand(0))) {
    if (GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
      if (GV->isConstant() && GV->hasDefinitiveInitializer() &&
          !cast<LoadInst>(LHSI)->isVolatile())
        if (Instruction *Res = foldCmpLoadFromIndexedGlobal(GEP, GV, I))
          return Res;
  }
  break;
}

return nullptr;
3263}

3265/// Some comparisons can be simplified.
3266/// In this case, we are looking for comparisons that look like
3267/// a check for a lossy truncation.
3268/// Folds:
3269///   icmp SrcPred (x & Mask), x    to    icmp DstPred x, Mask
3270/// Where Mask is some pattern that produces all-ones in low bits:
3271///    (-1 >> y)
3272///    ((-1 << y) >> y)     <- non-canonical, has extra uses
3273///   ~(-1 << y)
3274///    ((1 << y) + (-1))    <- non-canonical, has extra uses
3275/// The Mask can be a constant, too.
3276/// For some predicates, the operands are commutative.
3277/// For others, x can only be on a specific side.
3278static Value *foldICmpWithLowBitMaskedVal(ICmpInst &I,
                                        InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate SrcPred;
Value *X, *M, *Y;
auto m_VariableMask = m_CombineOr(
    m_CombineOr(m_Not(m_Shl(m_AllOnes(), m_Value())),
                m_Add(m_Shl(m_One(), m_Value()), m_AllOnes())),
    m_CombineOr(m_LShr(m_AllOnes(), m_Value()),
                m_LShr(m_Shl(m_AllOnes(), m_Value(Y)), m_Deferred(Y))));
auto m_Mask = m_CombineOr(m_VariableMask, m_LowBitMask());
if (!match(&I, m_c_ICmp(SrcPred,
                        m_c_And(m_CombineAnd(m_Mask, m_Value(M)), m_Value(X)),
                        m_Deferred(X))))
  return nullptr;

ICmpInst::Predicate DstPred;
switch (SrcPred) {
case ICmpInst::Predicate::ICMP_EQ:
  //  x & (-1 >> y) == x    ->    x u<= (-1 >> y)
  DstPred = ICmpInst::Predicate::ICMP_ULE;
  break;
case ICmpInst::Predicate::ICMP_NE:
  //  x & (-1 >> y) != x    ->    x u> (-1 >> y)
  DstPred = ICmpInst::Predicate::ICMP_UGT;
  break;
case ICmpInst::Predicate::ICMP_UGT:
  //  x u> x & (-1 >> y)    ->    x u> (-1 >> y)
  assert(X == I.getOperand(0) && "instsimplify took care of commut. variant")((X == I.getOperand(0) && "instsimplify took care of commut. variant"
) ? static_cast<void> (0) : __assert_fail ("X == I.getOperand(0) && \"instsimplify took care of commut. variant\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3305, __PRETTY_FUNCTION__));
  DstPred = ICmpInst::Predicate::ICMP_UGT;
  break;
case ICmpInst::Predicate::ICMP_UGE:
  //  x & (-1 >> y) u>= x    ->    x u<= (-1 >> y)
  assert(X == I.getOperand(1) && "instsimplify took care of commut. variant")((X == I.getOperand(1) && "instsimplify took care of commut. variant"
) ? static_cast<void> (0) : __assert_fail ("X == I.getOperand(1) && \"instsimplify took care of commut. variant\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3310, __PRETTY_FUNCTION__));
  DstPred = ICmpInst::Predicate::ICMP_ULE;
  break;
case ICmpInst::Predicate::ICMP_ULT:
  //  x & (-1 >> y) u< x    ->    x u> (-1 >> y)
  assert(X == I.getOperand(1) && "instsimplify took care of commut. variant")((X == I.getOperand(1) && "instsimplify took care of commut. variant"
) ? static_cast<void> (0) : __assert_fail ("X == I.getOperand(1) && \"instsimplify took care of commut. variant\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3315, __PRETTY_FUNCTION__));
  DstPred = ICmpInst::Predicate::ICMP_UGT;
  break;
case ICmpInst::Predicate::ICMP_ULE:
  //  x u<= x & (-1 >> y)    ->    x u<= (-1 >> y)
  assert(X == I.getOperand(0) && "instsimplify took care of commut. variant")((X == I.getOperand(0) && "instsimplify took care of commut. variant"
) ? static_cast<void> (0) : __assert_fail ("X == I.getOperand(0) && \"instsimplify took care of commut. variant\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3320, __PRETTY_FUNCTION__));
  DstPred = ICmpInst::Predicate::ICMP_ULE;
  break;
case ICmpInst::Predicate::ICMP_SGT:
  //  x s> x & (-1 >> y)    ->    x s> (-1 >> y)
  if (X != I.getOperand(0)) // X must be on LHS of comparison!
    return nullptr;         // Ignore the other case.
  if (!match(M, m_Constant())) // Can not do this fold with non-constant.
    return nullptr;
  if (!match(M, m_NonNegative())) // Must not have any -1 vector elements.
    return nullptr;
  DstPred = ICmpInst::Predicate::ICMP_SGT;
  break;
case ICmpInst::Predicate::ICMP_SGE:
  //  x & (-1 >> y) s>= x    ->    x s<= (-1 >> y)
  if (X != I.getOperand(1)) // X must be on RHS of comparison!
    return nullptr;         // Ignore the other case.
  if (!match(M, m_Constant())) // Can not do this fold with non-constant.
    return nullptr;
  if (!match(M, m_NonNegative())) // Must not have any -1 vector elements.
    return nullptr;
  DstPred = ICmpInst::Predicate::ICMP_SLE;
  break;
case ICmpInst::Predicate::ICMP_SLT:
  //  x & (-1 >> y) s< x    ->    x s> (-1 >> y)
  if (X != I.getOperand(1)) // X must be on RHS of comparison!
    return nullptr;         // Ignore the other case.
  if (!match(M, m_Constant())) // Can not do this fold with non-constant.
    return nullptr;
  if (!match(M, m_NonNegative())) // Must not have any -1 vector elements.
    return nullptr;
  DstPred = ICmpInst::Predicate::ICMP_SGT;
  break;
case ICmpInst::Predicate::ICMP_SLE:
  //  x s<= x & (-1 >> y)    ->    x s<= (-1 >> y)
  if (X != I.getOperand(0)) // X must be on LHS of comparison!
    return nullptr;         // Ignore the other case.
  if (!match(M, m_Constant())) // Can not do this fold with non-constant.
    return nullptr;
  if (!match(M, m_NonNegative())) // Must not have any -1 vector elements.
    return nullptr;
  DstPred = ICmpInst::Predicate::ICMP_SLE;
  break;
default:
  llvm_unreachable("All possible folds are handled.")::llvm::llvm_unreachable_internal("All possible folds are handled."
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3364);
}

return Builder.CreateICmp(DstPred, X, M);
3368}

3370/// Some comparisons can be simplified.
3371/// In this case, we are looking for comparisons that look like
3372/// a check for a lossy signed truncation.
3373/// Folds:   (MaskedBits is a constant.)
3374///   ((%x << MaskedBits) a>> MaskedBits) SrcPred %x
3375/// Into:
3376///   (add %x, (1 << (KeptBits-1))) DstPred (1 << KeptBits)
3377/// Where  KeptBits = bitwidth(%x) - MaskedBits
3378static Value *
3379foldICmpWithTruncSignExtendedVal(ICmpInst &I,
                               InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate SrcPred;
Value *X;
const APInt *C0, *C1; // FIXME: non-splats, potentially with undef.
// We are ok with 'shl' having multiple uses, but 'ashr' must be one-use.
if (!match(&I, m_c_ICmp(SrcPred,
                        m_OneUse(m_AShr(m_Shl(m_Value(X), m_APInt(C0)),
                                        m_APInt(C1))),
                        m_Deferred(X))))
  return nullptr;

// Potential handling of non-splats: for each element:
//  * if both are undef, replace with constant 0.
//    Because (1<<0) is OK and is 1, and ((1<<0)>>1) is also OK and is 0.
//  * if both are not undef, and are different, bailout.
//  * else, only one is undef, then pick the non-undef one.

// The shift amount must be equal.
if (*C0 != *C1)
  return nullptr;
const APInt &MaskedBits = *C0;
assert(MaskedBits != 0 && "shift by zero should be folded away already.")((MaskedBits != 0 && "shift by zero should be folded away already."
) ? static_cast<void> (0) : __assert_fail ("MaskedBits != 0 && \"shift by zero should be folded away already.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3401, __PRETTY_FUNCTION__));

ICmpInst::Predicate DstPred;
switch (SrcPred) {
case ICmpInst::Predicate::ICMP_EQ:
  // ((%x << MaskedBits) a>> MaskedBits) == %x
  //   =>
  // (add %x, (1 << (KeptBits-1))) u< (1 << KeptBits)
  DstPred = ICmpInst::Predicate::ICMP_ULT;
  break;
case ICmpInst::Predicate::ICMP_NE:
  // ((%x << MaskedBits) a>> MaskedBits) != %x
  //   =>
  // (add %x, (1 << (KeptBits-1))) u>= (1 << KeptBits)
  DstPred = ICmpInst::Predicate::ICMP_UGE;
  break;
// FIXME: are more folds possible?
default:
  return nullptr;
}

auto *XType = X->getType();
const unsigned XBitWidth = XType->getScalarSizeInBits();
const APInt BitWidth = APInt(XBitWidth, XBitWidth);
assert(BitWidth.ugt(MaskedBits) && "shifts should leave some bits untouched")((BitWidth.ugt(MaskedBits) && "shifts should leave some bits untouched"
) ? static_cast<void> (0) : __assert_fail ("BitWidth.ugt(MaskedBits) && \"shifts should leave some bits untouched\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3425, __PRETTY_FUNCTION__));

// KeptBits = bitwidth(%x) - MaskedBits
const APInt KeptBits = BitWidth - MaskedBits;
assert(KeptBits.ugt(0) && KeptBits.ult(BitWidth) && "unreachable")((KeptBits.ugt(0) && KeptBits.ult(BitWidth) &&
 "unreachable") ? static_cast<void> (0) : __assert_fail
 ("KeptBits.ugt(0) && KeptBits.ult(BitWidth) && \"unreachable\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3429, __PRETTY_FUNCTION__));
// ICmpCst = (1 << KeptBits)
const APInt ICmpCst = APInt(XBitWidth, 1).shl(KeptBits);
assert(ICmpCst.isPowerOf2())((ICmpCst.isPowerOf2()) ? static_cast<void> (0) : __assert_fail
 ("ICmpCst.isPowerOf2()", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3432, __PRETTY_FUNCTION__));
// AddCst = (1 << (KeptBits-1))
const APInt AddCst = ICmpCst.lshr(1);
assert(AddCst.ult(ICmpCst) && AddCst.isPowerOf2())((AddCst.ult(ICmpCst) && AddCst.isPowerOf2()) ? static_cast
<void> (0) : __assert_fail ("AddCst.ult(ICmpCst) && AddCst.isPowerOf2()"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3435, __PRETTY_FUNCTION__));

// T0 = add %x, AddCst
Value *T0 = Builder.CreateAdd(X, ConstantInt::get(XType, AddCst));
// T1 = T0 DstPred ICmpCst
Value *T1 = Builder.CreateICmp(DstPred, T0, ConstantInt::get(XType, ICmpCst));

return T1;
3443}

3445// Given pattern:
3446//   icmp eq/ne (and ((x shift Q), (y oppositeshift K))), 0
3447// we should move shifts to the same hand of 'and', i.e. rewrite as
3448//   icmp eq/ne (and (x shift (Q+K)), y), 0  iff (Q+K) u< bitwidth(x)
3449// We are only interested in opposite logical shifts here.
3450// One of the shifts can be truncated.
3451// If we can, we want to end up creating 'lshr' shift.
3452static Value *
3453foldShiftIntoShiftInAnotherHandOfAndInICmp(ICmpInst &I, const SimplifyQuery SQ,
                                         InstCombiner::BuilderTy &Builder) {
if (!I.isEquality() || !match(I.getOperand(1), m_Zero()) ||
    !I.getOperand(0)->hasOneUse())
  return nullptr;

auto m_AnyLogicalShift = m_LogicalShift(m_Value(), m_Value());

// Look for an 'and' of two logical shifts, one of which may be truncated.
// We use m_TruncOrSelf() on the RHS to correctly handle commutative case.
Instruction *XShift, *MaybeTruncation, *YShift;
if (!match(
        I.getOperand(0),
        m_c_And(m_CombineAnd(m_AnyLogicalShift, m_Instruction(XShift)),
                m_CombineAnd(m_TruncOrSelf(m_CombineAnd(
                                 m_AnyLogicalShift, m_Instruction(YShift))),
                             m_Instruction(MaybeTruncation)))))
  return nullptr;

// We potentially looked past 'trunc', but only when matching YShift,
// therefore YShift must have the widest type.
Instruction *WidestShift = YShift;
// Therefore XShift must have the shallowest type.
// Or they both have identical types if there was no truncation.
Instruction *NarrowestShift = XShift;

Type *WidestTy = WidestShift->getType();
assert(NarrowestShift->getType() == I.getOperand(0)->getType() &&((NarrowestShift->getType() == I.getOperand(0)->getType
() && "We did not look past any shifts while matching XShift though."
) ? static_cast<void> (0) : __assert_fail ("NarrowestShift->getType() == I.getOperand(0)->getType() && \"We did not look past any shifts while matching XShift though.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3481, __PRETTY_FUNCTION__))
       "We did not look past any shifts while matching XShift though.")((NarrowestShift->getType() == I.getOperand(0)->getType
() && "We did not look past any shifts while matching XShift though."
) ? static_cast<void> (0) : __assert_fail ("NarrowestShift->getType() == I.getOperand(0)->getType() && \"We did not look past any shifts while matching XShift though.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3481, __PRETTY_FUNCTION__));
bool HadTrunc = WidestTy != I.getOperand(0)->getType();

// If YShift is a 'lshr', swap the shifts around.
if (match(YShift, m_LShr(m_Value(), m_Value())))
  std::swap(XShift, YShift);

// The shifts must be in opposite directions.
auto XShiftOpcode = XShift->getOpcode();
if (XShiftOpcode == YShift->getOpcode())
  return nullptr; // Do not care about same-direction shifts here.

Value *X, *XShAmt, *Y, *YShAmt;
match(XShift, m_BinOp(m_Value(X), m_ZExtOrSelf(m_Value(XShAmt))));
match(YShift, m_BinOp(m_Value(Y), m_ZExtOrSelf(m_Value(YShAmt))));

// If one of the values being shifted is a constant, then we will end with
// and+icmp, and [zext+]shift instrs will be constant-folded. If they are not,
// however, we will need to ensure that we won't increase instruction count.
if (!isa<Constant>(X) && !isa<Constant>(Y)) {
  // At least one of the hands of the 'and' should be one-use shift.
  if (!match(I.getOperand(0),
             m_c_And(m_OneUse(m_AnyLogicalShift), m_Value())))
    return nullptr;
  if (HadTrunc) {
    // Due to the 'trunc', we will need to widen X. For that either the old
    // 'trunc' or the shift amt in the non-truncated shift should be one-use.
    if (!MaybeTruncation->hasOneUse() &&
        !NarrowestShift->getOperand(1)->hasOneUse())
      return nullptr;
  }
}

// We have two shift amounts from two different shifts. The types of those
// shift amounts may not match. If that's the case let's bailout now.
if (XShAmt->getType() != YShAmt->getType())
  return nullptr;

// Can we fold (XShAmt+YShAmt) ?
auto *NewShAmt = dyn_cast_or_null<Constant>(
    SimplifyAddInst(XShAmt, YShAmt, /*isNSW=*/false,
                    /*isNUW=*/false, SQ.getWithInstruction(&I)));
if (!NewShAmt)
  return nullptr;
NewShAmt = ConstantExpr::getZExtOrBitCast(NewShAmt, WidestTy);
unsigned WidestBitWidth = WidestTy->getScalarSizeInBits();

// Is the new shift amount smaller than the bit width?
// FIXME: could also rely on ConstantRange.
if (!match(NewShAmt,
           m_SpecificInt_ICMP(ICmpInst::Predicate::ICMP_ULT,
                              APInt(WidestBitWidth, WidestBitWidth))))
  return nullptr;

// An extra legality check is needed if we had trunc-of-lshr.
if (HadTrunc && match(WidestShift, m_LShr(m_Value(), m_Value()))) {
  auto CanFold = [NewShAmt, WidestBitWidth, NarrowestShift, SQ,
                  WidestShift]() {
    // It isn't obvious whether it's worth it to analyze non-constants here.
    // Also, let's basically give up on non-splat cases, pessimizing vectors.
    // If *any* of these preconditions matches we can perform the fold.
    Constant *NewShAmtSplat = NewShAmt->getType()->isVectorTy()
                                  ? NewShAmt->getSplatValue()
                                  : NewShAmt;
    // If it's edge-case shift (by 0 or by WidestBitWidth-1) we can fold.
    if (NewShAmtSplat &&
        (NewShAmtSplat->isNullValue() ||
         NewShAmtSplat->getUniqueInteger() == WidestBitWidth - 1))
      return true;
    // We consider *min* leading zeros so a single outlier
    // blocks the transform as opposed to allowing it.
    if (auto *C = dyn_cast<Constant>(NarrowestShift->getOperand(0))) {
      KnownBits Known = computeKnownBits(C, SQ.DL);
      unsigned MinLeadZero = Known.countMinLeadingZeros();
      // If the value being shifted has at most lowest bit set we can fold.
      unsigned MaxActiveBits = Known.getBitWidth() - MinLeadZero;
      if (MaxActiveBits <= 1)
        return true;
      // Precondition:  NewShAmt u<= countLeadingZeros(C)
      if (NewShAmtSplat && NewShAmtSplat->getUniqueInteger().ule(MinLeadZero))
        return true;
    }
    if (auto *C = dyn_cast<Constant>(WidestShift->getOperand(0))) {
      KnownBits Known = computeKnownBits(C, SQ.DL);
      unsigned MinLeadZero = Known.countMinLeadingZeros();
      // If the value being shifted has at most lowest bit set we can fold.
      unsigned MaxActiveBits = Known.getBitWidth() - MinLeadZero;
      if (MaxActiveBits <= 1)
        return true;
      // Precondition:  ((WidestBitWidth-1)-NewShAmt) u<= countLeadingZeros(C)
      if (NewShAmtSplat) {
        APInt AdjNewShAmt =
            (WidestBitWidth - 1) - NewShAmtSplat->getUniqueInteger();
        if (AdjNewShAmt.ule(MinLeadZero))
          return true;
      }
    }
    return false; // Can't tell if it's ok.
  };
  if (!CanFold())
    return nullptr;
}

// All good, we can do this fold.
X = Builder.CreateZExt(X, WidestTy);
Y = Builder.CreateZExt(Y, WidestTy);
// The shift is the same that was for X.
Value *T0 = XShiftOpcode == Instruction::BinaryOps::LShr
                ? Builder.CreateLShr(X, NewShAmt)
                : Builder.CreateShl(X, NewShAmt);
Value *T1 = Builder.CreateAnd(T0, Y);
return Builder.CreateICmp(I.getPredicate(), T1,
                          Constant::getNullValue(WidestTy));
3594}

3596/// Fold
3597///   (-1 u/ x) u< y
3598///   ((x * y) u/ x) != y
3599/// to
3600///   @llvm.umul.with.overflow(x, y) plus extraction of overflow bit
3601/// Note that the comparison is commutative, while inverted (u>=, ==) predicate
3602/// will mean that we are looking for the opposite answer.
3603Value *InstCombiner::foldUnsignedMultiplicationOverflowCheck(ICmpInst &I) {
ICmpInst::Predicate Pred;
Value *X, *Y;
Instruction *Mul;
bool NeedNegation;
// Look for: (-1 u/ x) u</u>= y
if (!I.isEquality() &&
    match(&I, m_c_ICmp(Pred, m_OneUse(m_UDiv(m_AllOnes(), m_Value(X))),
                       m_Value(Y)))) {
  Mul = nullptr;
  // Canonicalize as-if y was on RHS.
  if (I.getOperand(1) != Y)
    Pred = I.getSwappedPredicate();

  // Are we checking that overflow does not happen, or does happen?
  switch (Pred) {
  case ICmpInst::Predicate::ICMP_ULT:
    NeedNegation = false;
    break; // OK
  case ICmpInst::Predicate::ICMP_UGE:
    NeedNegation = true;
    break; // OK
  default:
    return nullptr; // Wrong predicate.
  }
} else // Look for: ((x * y) u/ x) !=/== y
    if (I.isEquality() &&
        match(&I, m_c_ICmp(Pred, m_Value(Y),
                           m_OneUse(m_UDiv(m_CombineAnd(m_c_Mul(m_Deferred(Y),
                                                                m_Value(X)),
                                                        m_Instruction(Mul)),
                                           m_Deferred(X)))))) {
  NeedNegation = Pred == ICmpInst::Predicate::ICMP_EQ;
} else
  return nullptr;

BuilderTy::InsertPointGuard Guard(Builder);
// If the pattern included (x * y), we'll want to insert new instructions
// right before that original multiplication so that we can replace it.
bool MulHadOtherUses = Mul && !Mul->hasOneUse();
if (MulHadOtherUses)
  Builder.SetInsertPoint(Mul);

Function *F = Intrinsic::getDeclaration(
    I.getModule(), Intrinsic::umul_with_overflow, X->getType());
CallInst *Call = Builder.CreateCall(F, {X, Y}, "umul");

// If the multiplication was used elsewhere, to ensure that we don't leave
// "duplicate" instructions, replace uses of that original multiplication
// with the multiplication result from the with.overflow intrinsic.
if (MulHadOtherUses)
  replaceInstUsesWith(*Mul, Builder.CreateExtractValue(Call, 0, "umul.val"));

Value *Res = Builder.CreateExtractValue(Call, 1, "umul.ov");
if (NeedNegation) // This technically increases instruction count.
  Res = Builder.CreateNot(Res, "umul.not.ov");

return Res;
3661}

3663/// Try to fold icmp (binop), X or icmp X, (binop).
3664/// TODO: A large part of this logic is duplicated in InstSimplify's
3665/// simplifyICmpWithBinOp(). We should be able to share that and avoid the code
3666/// duplication.
3667Instruction *InstCombiner::foldICmpBinOp(ICmpInst &I, const SimplifyQuery &SQ) {
const SimplifyQuery Q = SQ.getWithInstruction(&I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);

// Special logic for binary operators.
BinaryOperator *BO0 = dyn_cast<BinaryOperator>(Op0);
BinaryOperator *BO1 = dyn_cast<BinaryOperator>(Op1);
if (!BO0 && !BO1)
  return nullptr;

const CmpInst::Predicate Pred = I.getPredicate();
Value *X;

// Convert add-with-unsigned-overflow comparisons into a 'not' with compare.
// (Op1 + X) u</u>= Op1 --> ~Op1 u</u>= X
if (match(Op0, m_OneUse(m_c_Add(m_Specific(Op1), m_Value(X)))) &&
    (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_UGE))
  return new ICmpInst(Pred, Builder.CreateNot(Op1), X);
// Op0 u>/u<= (Op0 + X) --> X u>/u<= ~Op0
if (match(Op1, m_OneUse(m_c_Add(m_Specific(Op0), m_Value(X)))) &&
    (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_ULE))
  return new ICmpInst(Pred, X, Builder.CreateNot(Op0));

bool NoOp0WrapProblem = false, NoOp1WrapProblem = false;
if (BO0 && isa<OverflowingBinaryOperator>(BO0))
  NoOp0WrapProblem =
      ICmpInst::isEquality(Pred) ||
      (CmpInst::isUnsigned(Pred) && BO0->hasNoUnsignedWrap()) ||
      (CmpInst::isSigned(Pred) && BO0->hasNoSignedWrap());
if (BO1 && isa<OverflowingBinaryOperator>(BO1))
  NoOp1WrapProblem =
      ICmpInst::isEquality(Pred) ||
      (CmpInst::isUnsigned(Pred) && BO1->hasNoUnsignedWrap()) ||
      (CmpInst::isSigned(Pred) && BO1->hasNoSignedWrap());

// Analyze the case when either Op0 or Op1 is an add instruction.
// Op0 = A + B (or A and B are null); Op1 = C + D (or C and D are null).
Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
if (BO0 && BO0->getOpcode() == Instruction::Add) {
  A = BO0->getOperand(0);
  B = BO0->getOperand(1);
}
if (BO1 && BO1->getOpcode() == Instruction::Add) {
  C = BO1->getOperand(0);
  D = BO1->getOperand(1);
}

// icmp (A+B), A -> icmp B, 0 for equalities or if there is no overflow.
// icmp (A+B), B -> icmp A, 0 for equalities or if there is no overflow.
if ((A == Op1 || B == Op1) && NoOp0WrapProblem)
  return new ICmpInst(Pred, A == Op1 ? B : A,
                      Constant::getNullValue(Op1->getType()));

// icmp C, (C+D) -> icmp 0, D for equalities or if there is no overflow.
// icmp D, (C+D) -> icmp 0, C for equalities or if there is no overflow.
if ((C == Op0 || D == Op0) && NoOp1WrapProblem)
  return new ICmpInst(Pred, Constant::getNullValue(Op0->getType()),
                      C == Op0 ? D : C);

// icmp (A+B), (A+D) -> icmp B, D for equalities or if there is no overflow.
if (A && C && (A == C || A == D || B == C || B == D) && NoOp0WrapProblem &&
    NoOp1WrapProblem) {
  // Determine Y and Z in the form icmp (X+Y), (X+Z).
  Value *Y, *Z;
  if (A == C) {
    // C + B == C + D  ->  B == D
    Y = B;
    Z = D;
  } else if (A == D) {
    // D + B == C + D  ->  B == C
    Y = B;
    Z = C;
  } else if (B == C) {
    // A + C == C + D  ->  A == D
    Y = A;
    Z = D;
  } else {
    assert(B == D)((B == D) ? static_cast<void> (0) : __assert_fail ("B == D"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3744, __PRETTY_FUNCTION__));
    // A + D == C + D  ->  A == C
    Y = A;
    Z = C;
  }
  return new ICmpInst(Pred, Y, Z);
}

// icmp slt (A + -1), Op1 -> icmp sle A, Op1
if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SLT &&
    match(B, m_AllOnes()))
  return new ICmpInst(CmpInst::ICMP_SLE, A, Op1);

// icmp sge (A + -1), Op1 -> icmp sgt A, Op1
if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SGE &&
    match(B, m_AllOnes()))
  return new ICmpInst(CmpInst::ICMP_SGT, A, Op1);

// icmp sle (A + 1), Op1 -> icmp slt A, Op1
if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SLE && match(B, m_One()))
  return new ICmpInst(CmpInst::ICMP_SLT, A, Op1);

// icmp sgt (A + 1), Op1 -> icmp sge A, Op1
if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_SGT && match(B, m_One()))
  return new ICmpInst(CmpInst::ICMP_SGE, A, Op1);

// icmp sgt Op0, (C + -1) -> icmp sge Op0, C
if (C && NoOp1WrapProblem && Pred == CmpInst::ICMP_SGT &&
    match(D, m_AllOnes()))
  return new ICmpInst(CmpInst::ICMP_SGE, Op0, C);

// icmp sle Op0, (C + -1) -> icmp slt Op0, C
if (C && NoOp1WrapProblem && Pred == CmpInst::ICMP_SLE &&
    match(D, m_AllOnes()))
  return new ICmpInst(CmpInst::ICMP_SLT, Op0, C);

// icmp sge Op0, (C + 1) -> icmp sgt Op0, C
if (C && NoOp1WrapProblem && Pred == CmpInst::ICMP_SGE && match(D, m_One()))
  return new ICmpInst(CmpInst::ICMP_SGT, Op0, C);

// icmp slt Op0, (C + 1) -> icmp sle Op0, C
if (C && NoOp1WrapProblem && Pred == CmpInst::ICMP_SLT && match(D, m_One()))
  return new ICmpInst(CmpInst::ICMP_SLE, Op0, C);

// TODO: The subtraction-related identities shown below also hold, but
// canonicalization from (X -nuw 1) to (X + -1) means that the combinations
// wouldn't happen even if they were implemented.
//
// icmp ult (A - 1), Op1 -> icmp ule A, Op1
// icmp uge (A - 1), Op1 -> icmp ugt A, Op1
// icmp ugt Op0, (C - 1) -> icmp uge Op0, C
// icmp ule Op0, (C - 1) -> icmp ult Op0, C

// icmp ule (A + 1), Op0 -> icmp ult A, Op1
if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_ULE && match(B, m_One()))
  return new ICmpInst(CmpInst::ICMP_ULT, A, Op1);

// icmp ugt (A + 1), Op0 -> icmp uge A, Op1
if (A && NoOp0WrapProblem && Pred == CmpInst::ICMP_UGT && match(B, m_One()))
  return new ICmpInst(CmpInst::ICMP_UGE, A, Op1);

// icmp uge Op0, (C + 1) -> icmp ugt Op0, C
if (C && NoOp1WrapProblem && Pred == CmpInst::ICMP_UGE && match(D, m_One()))
  return new ICmpInst(CmpInst::ICMP_UGT, Op0, C);

// icmp ult Op0, (C + 1) -> icmp ule Op0, C
if (C && NoOp1WrapProblem && Pred == CmpInst::ICMP_ULT && match(D, m_One()))
  return new ICmpInst(CmpInst::ICMP_ULE, Op0, C);

// if C1 has greater magnitude than C2:
//  icmp (A + C1), (C + C2) -> icmp (A + C3), C
//  s.t. C3 = C1 - C2
//
// if C2 has greater magnitude than C1:
//  icmp (A + C1), (C + C2) -> icmp A, (C + C3)
//  s.t. C3 = C2 - C1
if (A && C && NoOp0WrapProblem && NoOp1WrapProblem &&
    (BO0->hasOneUse() || BO1->hasOneUse()) && !I.isUnsigned())
  if (ConstantInt *C1 = dyn_cast<ConstantInt>(B))
    if (ConstantInt *C2 = dyn_cast<ConstantInt>(D)) {
      const APInt &AP1 = C1->getValue();
      const APInt &AP2 = C2->getValue();
      if (AP1.isNegative() == AP2.isNegative()) {
        APInt AP1Abs = C1->getValue().abs();
        APInt AP2Abs = C2->getValue().abs();
        if (AP1Abs.uge(AP2Abs)) {
          ConstantInt *C3 = Builder.getInt(AP1 - AP2);
          Value *NewAdd = Builder.CreateNSWAdd(A, C3);
          return new ICmpInst(Pred, NewAdd, C);
        } else {
          ConstantInt *C3 = Builder.getInt(AP2 - AP1);
          Value *NewAdd = Builder.CreateNSWAdd(C, C3);
          return new ICmpInst(Pred, A, NewAdd);
        }
      }
    }

// Analyze the case when either Op0 or Op1 is a sub instruction.
// Op0 = A - B (or A and B are null); Op1 = C - D (or C and D are null).
A = nullptr;
B = nullptr;
C = nullptr;
D = nullptr;
if (BO0 && BO0->getOpcode() == Instruction::Sub) {
  A = BO0->getOperand(0);
  B = BO0->getOperand(1);
}
if (BO1 && BO1->getOpcode() == Instruction::Sub) {
  C = BO1->getOperand(0);
  D = BO1->getOperand(1);
}

// icmp (A-B), A -> icmp 0, B for equalities or if there is no overflow.
if (A == Op1 && NoOp0WrapProblem)
  return new ICmpInst(Pred, Constant::getNullValue(Op1->getType()), B);
// icmp C, (C-D) -> icmp D, 0 for equalities or if there is no overflow.
if (C == Op0 && NoOp1WrapProblem)
  return new ICmpInst(Pred, D, Constant::getNullValue(Op0->getType()));

// Convert sub-with-unsigned-overflow comparisons into a comparison of args.
// (A - B) u>/u<= A --> B u>/u<= A
if (A == Op1 && (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_ULE))
  return new ICmpInst(Pred, B, A);
// C u</u>= (C - D) --> C u</u>= D
if (C == Op0 && (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_UGE))
  return new ICmpInst(Pred, C, D);
// (A - B) u>=/u< A --> B u>/u<= A  iff B != 0
if (A == Op1 && (Pred == ICmpInst::ICMP_UGE || Pred == ICmpInst::ICMP_ULT) &&
    isKnownNonZero(B, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT))
  return new ICmpInst(CmpInst::getFlippedStrictnessPredicate(Pred), B, A);
// C u<=/u> (C - D) --> C u</u>= D  iff B != 0
if (C == Op0 && (Pred == ICmpInst::ICMP_ULE || Pred == ICmpInst::ICMP_UGT) &&
    isKnownNonZero(D, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT))
  return new ICmpInst(CmpInst::getFlippedStrictnessPredicate(Pred), C, D);

// icmp (A-B), (C-B) -> icmp A, C for equalities or if there is no overflow.
if (B && D && B == D && NoOp0WrapProblem && NoOp1WrapProblem)
  return new ICmpInst(Pred, A, C);

// icmp (A-B), (A-D) -> icmp D, B for equalities or if there is no overflow.
if (A && C && A == C && NoOp0WrapProblem && NoOp1WrapProblem)
  return new ICmpInst(Pred, D, B);

// icmp (0-X) < cst --> x > -cst
if (NoOp0WrapProblem && ICmpInst::isSigned(Pred)) {
  Value *X;
  if (match(BO0, m_Neg(m_Value(X))))
    if (Constant *RHSC = dyn_cast<Constant>(Op1))
      if (RHSC->isNotMinSignedValue())
        return new ICmpInst(I.getSwappedPredicate(), X,
                            ConstantExpr::getNeg(RHSC));
}

BinaryOperator *SRem = nullptr;
// icmp (srem X, Y), Y
if (BO0 && BO0->getOpcode() == Instruction::SRem && Op1 == BO0->getOperand(1))
  SRem = BO0;
// icmp Y, (srem X, Y)
else if (BO1 && BO1->getOpcode() == Instruction::SRem &&
         Op0 == BO1->getOperand(1))
  SRem = BO1;
if (SRem) {
  // We don't check hasOneUse to avoid increasing register pressure because
  // the value we use is the same value this instruction was already using.
  switch (SRem == BO0 ? ICmpInst::getSwappedPredicate(Pred) : Pred) {
  default:
    break;
  case ICmpInst::ICMP_EQ:
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  case ICmpInst::ICMP_NE:
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  case ICmpInst::ICMP_SGT:
  case ICmpInst::ICMP_SGE:
    return new ICmpInst(ICmpInst::ICMP_SGT, SRem->getOperand(1),
                        Constant::getAllOnesValue(SRem->getType()));
  case ICmpInst::ICMP_SLT:
  case ICmpInst::ICMP_SLE:
    return new ICmpInst(ICmpInst::ICMP_SLT, SRem->getOperand(1),
                        Constant::getNullValue(SRem->getType()));
  }
}

if (BO0 && BO1 && BO0->getOpcode() == BO1->getOpcode() && BO0->hasOneUse() &&
    BO1->hasOneUse() && BO0->getOperand(1) == BO1->getOperand(1)) {
  switch (BO0->getOpcode()) {
  default:
    break;
  case Instruction::Add:
  case Instruction::Sub:
  case Instruction::Xor: {
    if (I.isEquality()) // a+x icmp eq/ne b+x --> a icmp b
      return new ICmpInst(Pred, BO0->getOperand(0), BO1->getOperand(0));

    const APInt *C;
    if (match(BO0->getOperand(1), m_APInt(C))) {
      // icmp u/s (a ^ signmask), (b ^ signmask) --> icmp s/u a, b
      if (C->isSignMask()) {
        ICmpInst::Predicate NewPred =
            I.isSigned() ? I.getUnsignedPredicate() : I.getSignedPredicate();
        return new ICmpInst(NewPred, BO0->getOperand(0), BO1->getOperand(0));
      }

      // icmp u/s (a ^ maxsignval), (b ^ maxsignval) --> icmp s/u' a, b
      if (BO0->getOpcode() == Instruction::Xor && C->isMaxSignedValue()) {
        ICmpInst::Predicate NewPred =
            I.isSigned() ? I.getUnsignedPredicate() : I.getSignedPredicate();
        NewPred = I.getSwappedPredicate(NewPred);
        return new ICmpInst(NewPred, BO0->getOperand(0), BO1->getOperand(0));
      }
    }
    break;
  }
  case Instruction::Mul: {
    if (!I.isEquality())
      break;

    const APInt *C;
    if (match(BO0->getOperand(1), m_APInt(C)) && !C->isNullValue() &&
        !C->isOneValue()) {
      // icmp eq/ne (X * C), (Y * C) --> icmp (X & Mask), (Y & Mask)
      // Mask = -1 >> count-trailing-zeros(C).
      if (unsigned TZs = C->countTrailingZeros()) {
        Constant *Mask = ConstantInt::get(
            BO0->getType(),
            APInt::getLowBitsSet(C->getBitWidth(), C->getBitWidth() - TZs));
        Value *And1 = Builder.CreateAnd(BO0->getOperand(0), Mask);
        Value *And2 = Builder.CreateAnd(BO1->getOperand(0), Mask);
        return new ICmpInst(Pred, And1, And2);
      }
      // If there are no trailing zeros in the multiplier, just eliminate
      // the multiplies (no masking is needed):
      // icmp eq/ne (X * C), (Y * C) --> icmp eq/ne X, Y
      return new ICmpInst(Pred, BO0->getOperand(0), BO1->getOperand(0));
    }
    break;
  }
  case Instruction::UDiv:
  case Instruction::LShr:
    if (I.isSigned() || !BO0->isExact() || !BO1->isExact())
      break;
    return new ICmpInst(Pred, BO0->getOperand(0), BO1->getOperand(0));

  case Instruction::SDiv:
    if (!I.isEquality() || !BO0->isExact() || !BO1->isExact())
      break;
    return new ICmpInst(Pred, BO0->getOperand(0), BO1->getOperand(0));

  case Instruction::AShr:
    if (!BO0->isExact() || !BO1->isExact())
      break;
    return new ICmpInst(Pred, BO0->getOperand(0), BO1->getOperand(0));

  case Instruction::Shl: {
    bool NUW = BO0->hasNoUnsignedWrap() && BO1->hasNoUnsignedWrap();
    bool NSW = BO0->hasNoSignedWrap() && BO1->hasNoSignedWrap();
    if (!NUW && !NSW)
      break;
    if (!NSW && I.isSigned())
      break;
    return new ICmpInst(Pred, BO0->getOperand(0), BO1->getOperand(0));
  }
  }
}

if (BO0) {
  // Transform  A & (L - 1) `ult` L --> L != 0
  auto LSubOne = m_Add(m_Specific(Op1), m_AllOnes());
  auto BitwiseAnd = m_c_And(m_Value(), LSubOne);

  if (match(BO0, BitwiseAnd) && Pred == ICmpInst::ICMP_ULT) {
    auto *Zero = Constant::getNullValue(BO0->getType());
    return new ICmpInst(ICmpInst::ICMP_NE, Op1, Zero);
  }
}

if (Value *V = foldUnsignedMultiplicationOverflowCheck(I))
  return replaceInstUsesWith(I, V);

if (Value *V = foldICmpWithLowBitMaskedVal(I, Builder))
  return replaceInstUsesWith(I, V);

if (Value *V = foldICmpWithTruncSignExtendedVal(I, Builder))
  return replaceInstUsesWith(I, V);

if (Value *V = foldShiftIntoShiftInAnotherHandOfAndInICmp(I, SQ, Builder))
  return replaceInstUsesWith(I, V);

return nullptr;
4032}

4034/// Fold icmp Pred min|max(X, Y), X.
4035static Instruction *foldICmpWithMinMax(ICmpInst &Cmp) {
ICmpInst::Predicate Pred = Cmp.getPredicate();
Value *Op0 = Cmp.getOperand(0);
Value *X = Cmp.getOperand(1);

// Canonicalize minimum or maximum operand to LHS of the icmp.
if (match(X, m_c_SMin(m_Specific(Op0), m_Value())) ||
    match(X, m_c_SMax(m_Specific(Op0), m_Value())) ||
    match(X, m_c_UMin(m_Specific(Op0), m_Value())) ||
    match(X, m_c_UMax(m_Specific(Op0), m_Value()))) {
  std::swap(Op0, X);
  Pred = Cmp.getSwappedPredicate();
}

Value *Y;
if (match(Op0, m_c_SMin(m_Specific(X), m_Value(Y)))) {
  // smin(X, Y)  == X --> X s<= Y
  // smin(X, Y) s>= X --> X s<= Y
  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_SGE)
    return new ICmpInst(ICmpInst::ICMP_SLE, X, Y);

  // smin(X, Y) != X --> X s> Y
  // smin(X, Y) s< X --> X s> Y
  if (Pred == CmpInst::ICMP_NE || Pred == CmpInst::ICMP_SLT)
    return new ICmpInst(ICmpInst::ICMP_SGT, X, Y);

  // These cases should be handled in InstSimplify:
  // smin(X, Y) s<= X --> true
  // smin(X, Y) s> X --> false
  return nullptr;
}

if (match(Op0, m_c_SMax(m_Specific(X), m_Value(Y)))) {
  // smax(X, Y)  == X --> X s>= Y
  // smax(X, Y) s<= X --> X s>= Y
  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_SLE)
    return new ICmpInst(ICmpInst::ICMP_SGE, X, Y);

  // smax(X, Y) != X --> X s< Y
  // smax(X, Y) s> X --> X s< Y
  if (Pred == CmpInst::ICMP_NE || Pred == CmpInst::ICMP_SGT)
    return new ICmpInst(ICmpInst::ICMP_SLT, X, Y);

  // These cases should be handled in InstSimplify:
  // smax(X, Y) s>= X --> true
  // smax(X, Y) s< X --> false
  return nullptr;
}

if (match(Op0, m_c_UMin(m_Specific(X), m_Value(Y)))) {
  // umin(X, Y)  == X --> X u<= Y
  // umin(X, Y) u>= X --> X u<= Y
  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_UGE)
    return new ICmpInst(ICmpInst::ICMP_ULE, X, Y);

  // umin(X, Y) != X --> X u> Y
  // umin(X, Y) u< X --> X u> Y
  if (Pred == CmpInst::ICMP_NE || Pred == CmpInst::ICMP_ULT)
    return new ICmpInst(ICmpInst::ICMP_UGT, X, Y);

  // These cases should be handled in InstSimplify:
  // umin(X, Y) u<= X --> true
  // umin(X, Y) u> X --> false
  return nullptr;
}

if (match(Op0, m_c_UMax(m_Specific(X), m_Value(Y)))) {
  // umax(X, Y)  == X --> X u>= Y
  // umax(X, Y) u<= X --> X u>= Y
  if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_ULE)
    return new ICmpInst(ICmpInst::ICMP_UGE, X, Y);

  // umax(X, Y) != X --> X u< Y
  // umax(X, Y) u> X --> X u< Y
  if (Pred == CmpInst::ICMP_NE || Pred == CmpInst::ICMP_UGT)
    return new ICmpInst(ICmpInst::ICMP_ULT, X, Y);

  // These cases should be handled in InstSimplify:
  // umax(X, Y) u>= X --> true
  // umax(X, Y) u< X --> false
  return nullptr;
}

return nullptr;
4119}

4121Instruction *InstCombiner::foldICmpEquality(ICmpInst &I) {
if (!I.isEquality())
  return nullptr;

Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
const CmpInst::Predicate Pred = I.getPredicate();
Value *A, *B, *C, *D;
if (match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
  if (A == Op1 || B == Op1) { // (A^B) == A  ->  B == 0
    Value *OtherVal = A == Op1 ? B : A;
    return new ICmpInst(Pred, OtherVal, Constant::getNullValue(A->getType()));
  }

  if (match(Op1, m_Xor(m_Value(C), m_Value(D)))) {
    // A^c1 == C^c2 --> A == C^(c1^c2)
    ConstantInt *C1, *C2;
    if (match(B, m_ConstantInt(C1)) && match(D, m_ConstantInt(C2)) &&
        Op1->hasOneUse()) {
      Constant *NC = Builder.getInt(C1->getValue() ^ C2->getValue());
      Value *Xor = Builder.CreateXor(C, NC);
      return new ICmpInst(Pred, A, Xor);
    }

    // A^B == A^D -> B == D
    if (A == C)
      return new ICmpInst(Pred, B, D);
    if (A == D)
      return new ICmpInst(Pred, B, C);
    if (B == C)
      return new ICmpInst(Pred, A, D);
    if (B == D)
      return new ICmpInst(Pred, A, C);
  }
}

if (match(Op1, m_Xor(m_Value(A), m_Value(B))) && (A == Op0 || B == Op0)) {
  // A == (A^B)  ->  B == 0
  Value *OtherVal = A == Op0 ? B : A;
  return new ICmpInst(Pred, OtherVal, Constant::getNullValue(A->getType()));
}

// (X&Z) == (Y&Z) -> (X^Y) & Z == 0
if (match(Op0, m_OneUse(m_And(m_Value(A), m_Value(B)))) &&
    match(Op1, m_OneUse(m_And(m_Value(C), m_Value(D))))) {
  Value *X = nullptr, *Y = nullptr, *Z = nullptr;

  if (A == C) {
    X = B;
    Y = D;
    Z = A;
  } else if (A == D) {
    X = B;
    Y = C;
    Z = A;
  } else if (B == C) {
    X = A;
    Y = D;
    Z = B;
  } else if (B == D) {
    X = A;
    Y = C;
    Z = B;
  }

  if (X) { // Build (X^Y) & Z
    Op1 = Builder.CreateXor(X, Y);
    Op1 = Builder.CreateAnd(Op1, Z);
    I.setOperand(0, Op1);
    I.setOperand(1, Constant::getNullValue(Op1->getType()));
    return &I;
  }
}

// Transform (zext A) == (B & (1<<X)-1) --> A == (trunc B)
// and       (B & (1<<X)-1) == (zext A) --> A == (trunc B)
ConstantInt *Cst1;
if ((Op0->hasOneUse() && match(Op0, m_ZExt(m_Value(A))) &&
     match(Op1, m_And(m_Value(B), m_ConstantInt(Cst1)))) ||
    (Op1->hasOneUse() && match(Op0, m_And(m_Value(B), m_ConstantInt(Cst1))) &&
     match(Op1, m_ZExt(m_Value(A))))) {
  APInt Pow2 = Cst1->getValue() + 1;
  if (Pow2.isPowerOf2() && isa<IntegerType>(A->getType()) &&
      Pow2.logBase2() == cast<IntegerType>(A->getType())->getBitWidth())
    return new ICmpInst(Pred, A, Builder.CreateTrunc(B, A->getType()));
}

// (A >> C) == (B >> C) --> (A^B) u< (1 << C)
// For lshr and ashr pairs.
if ((match(Op0, m_OneUse(m_LShr(m_Value(A), m_ConstantInt(Cst1)))) &&
     match(Op1, m_OneUse(m_LShr(m_Value(B), m_Specific(Cst1))))) ||
    (match(Op0, m_OneUse(m_AShr(m_Value(A), m_ConstantInt(Cst1)))) &&
     match(Op1, m_OneUse(m_AShr(m_Value(B), m_Specific(Cst1)))))) {
  unsigned TypeBits = Cst1->getBitWidth();
  unsigned ShAmt = (unsigned)Cst1->getLimitedValue(TypeBits);
  if (ShAmt < TypeBits && ShAmt != 0) {
    ICmpInst::Predicate NewPred =
        Pred == ICmpInst::ICMP_NE ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_ULT;
    Value *Xor = Builder.CreateXor(A, B, I.getName() + ".unshifted");
    APInt CmpVal = APInt::getOneBitSet(TypeBits, ShAmt);
    return new ICmpInst(NewPred, Xor, Builder.getInt(CmpVal));
  }
}

// (A << C) == (B << C) --> ((A^B) & (~0U >> C)) == 0
if (match(Op0, m_OneUse(m_Shl(m_Value(A), m_ConstantInt(Cst1)))) &&
    match(Op1, m_OneUse(m_Shl(m_Value(B), m_Specific(Cst1))))) {
  unsigned TypeBits = Cst1->getBitWidth();
  unsigned ShAmt = (unsigned)Cst1->getLimitedValue(TypeBits);
  if (ShAmt < TypeBits && ShAmt != 0) {
    Value *Xor = Builder.CreateXor(A, B, I.getName() + ".unshifted");
    APInt AndVal = APInt::getLowBitsSet(TypeBits, TypeBits - ShAmt);
    Value *And = Builder.CreateAnd(Xor, Builder.getInt(AndVal),
                                    I.getName() + ".mask");
    return new ICmpInst(Pred, And, Constant::getNullValue(Cst1->getType()));
  }
}

// Transform "icmp eq (trunc (lshr(X, cst1)), cst" to
// "icmp (and X, mask), cst"
uint64_t ShAmt = 0;
if (Op0->hasOneUse() &&
    match(Op0, m_Trunc(m_OneUse(m_LShr(m_Value(A), m_ConstantInt(ShAmt))))) &&
    match(Op1, m_ConstantInt(Cst1)) &&
    // Only do this when A has multiple uses.  This is most important to do
    // when it exposes other optimizations.
    !A->hasOneUse()) {
  unsigned ASize = cast<IntegerType>(A->getType())->getPrimitiveSizeInBits();

  if (ShAmt < ASize) {
    APInt MaskV =
        APInt::getLowBitsSet(ASize, Op0->getType()->getPrimitiveSizeInBits());
    MaskV <<= ShAmt;

    APInt CmpV = Cst1->getValue().zext(ASize);
    CmpV <<= ShAmt;

    Value *Mask = Builder.CreateAnd(A, Builder.getInt(MaskV));
    return new ICmpInst(Pred, Mask, Builder.getInt(CmpV));
  }
}

// If both operands are byte-swapped or bit-reversed, just compare the
// original values.
// TODO: Move this to a function similar to foldICmpIntrinsicWithConstant()
// and handle more intrinsics.
if ((match(Op0, m_BSwap(m_Value(A))) && match(Op1, m_BSwap(m_Value(B)))) ||
    (match(Op0, m_BitReverse(m_Value(A))) &&
     match(Op1, m_BitReverse(m_Value(B)))))
  return new ICmpInst(Pred, A, B);

// Canonicalize checking for a power-of-2-or-zero value:
// (A & (A-1)) == 0 --> ctpop(A) < 2 (two commuted variants)
// ((A-1) & A) != 0 --> ctpop(A) > 1 (two commuted variants)
if (!match(Op0, m_OneUse(m_c_And(m_Add(m_Value(A), m_AllOnes()),
                                 m_Deferred(A)))) ||
    !match(Op1, m_ZeroInt()))
  A = nullptr;

// (A & -A) == A --> ctpop(A) < 2 (four commuted variants)
// (-A & A) != A --> ctpop(A) > 1 (four commuted variants)
if (match(Op0, m_OneUse(m_c_And(m_Neg(m_Specific(Op1)), m_Specific(Op1)))))
  A = Op1;
else if (match(Op1,
               m_OneUse(m_c_And(m_Neg(m_Specific(Op0)), m_Specific(Op0)))))
  A = Op0;

if (A) {
  Type *Ty = A->getType();
  CallInst *CtPop = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, A);
  return Pred == ICmpInst::ICMP_EQ
      ? new ICmpInst(ICmpInst::ICMP_ULT, CtPop, ConstantInt::get(Ty, 2))
      : new ICmpInst(ICmpInst::ICMP_UGT, CtPop, ConstantInt::get(Ty, 1));
}

return nullptr;
4296}

4298static Instruction *foldICmpWithZextOrSext(ICmpInst &ICmp,
                                         InstCombiner::BuilderTy &Builder) {
assert(isa<CastInst>(ICmp.getOperand(0)) && "Expected cast for operand 0")((isa<CastInst>(ICmp.getOperand(0)) && "Expected cast for operand 0"
) ? static_cast<void> (0) : __assert_fail ("isa<CastInst>(ICmp.getOperand(0)) && \"Expected cast for operand 0\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4300, __PRETTY_FUNCTION__));
auto *CastOp0 = cast<CastInst>(ICmp.getOperand(0));
Value *X;
if (!match(CastOp0, m_ZExtOrSExt(m_Value(X))))
  return nullptr;

bool IsSignedExt = CastOp0->getOpcode() == Instruction::SExt;
bool IsSignedCmp = ICmp.isSigned();
if (auto *CastOp1 = dyn_cast<CastInst>(ICmp.getOperand(1))) {
  // If the signedness of the two casts doesn't agree (i.e. one is a sext
  // and the other is a zext), then we can't handle this.
  // TODO: This is too strict. We can handle some predicates (equality?).
  if (CastOp0->getOpcode() != CastOp1->getOpcode())
    return nullptr;

  // Not an extension from the same type?
  Value *Y = CastOp1->getOperand(0);
  Type *XTy = X->getType(), *YTy = Y->getType();
  if (XTy != YTy) {
    // One of the casts must have one use because we are creating a new cast.
    if (!CastOp0->hasOneUse() && !CastOp1->hasOneUse())
      return nullptr;
    // Extend the narrower operand to the type of the wider operand.
    if (XTy->getScalarSizeInBits() < YTy->getScalarSizeInBits())
      X = Builder.CreateCast(CastOp0->getOpcode(), X, YTy);
    else if (YTy->getScalarSizeInBits() < XTy->getScalarSizeInBits())
      Y = Builder.CreateCast(CastOp0->getOpcode(), Y, XTy);
    else
      return nullptr;
  }

  // (zext X) == (zext Y) --> X == Y
  // (sext X) == (sext Y) --> X == Y
  if (ICmp.isEquality())
    return new ICmpInst(ICmp.getPredicate(), X, Y);

  // A signed comparison of sign extended values simplifies into a
  // signed comparison.
  if (IsSignedCmp && IsSignedExt)
    return new ICmpInst(ICmp.getPredicate(), X, Y);

  // The other three cases all fold into an unsigned comparison.
  return new ICmpInst(ICmp.getUnsignedPredicate(), X, Y);
}

// Below here, we are only folding a compare with constant.
auto *C = dyn_cast<Constant>(ICmp.getOperand(1));
if (!C)
  return nullptr;

// Compute the constant that would happen if we truncated to SrcTy then
// re-extended to DestTy.
Type *SrcTy = CastOp0->getSrcTy();
Type *DestTy = CastOp0->getDestTy();
Constant *Res1 = ConstantExpr::getTrunc(C, SrcTy);
Constant *Res2 = ConstantExpr::getCast(CastOp0->getOpcode(), Res1, DestTy);

// If the re-extended constant didn't change...
if (Res2 == C) {
  if (ICmp.isEquality())
    return new ICmpInst(ICmp.getPredicate(), X, Res1);

  // A signed comparison of sign extended values simplifies into a
  // signed comparison.
  if (IsSignedExt && IsSignedCmp)
    return new ICmpInst(ICmp.getPredicate(), X, Res1);

  // The other three cases all fold into an unsigned comparison.
  return new ICmpInst(ICmp.getUnsignedPredicate(), X, Res1);
}

// The re-extended constant changed, partly changed (in the case of a vector),
// or could not be determined to be equal (in the case of a constant
// expression), so the constant cannot be represented in the shorter type.
// All the cases that fold to true or false will have already been handled
// by SimplifyICmpInst, so only deal with the tricky case.
if (IsSignedCmp || !IsSignedExt || !isa<ConstantInt>(C))
  return nullptr;

// Is source op positive?
// icmp ult (sext X), C --> icmp sgt X, -1
if (ICmp.getPredicate() == ICmpInst::ICMP_ULT)
  return new ICmpInst(CmpInst::ICMP_SGT, X, Constant::getAllOnesValue(SrcTy));

// Is source op negative?
// icmp ugt (sext X), C --> icmp slt X, 0
assert(ICmp.getPredicate() == ICmpInst::ICMP_UGT && "ICmp should be folded!")((ICmp.getPredicate() == ICmpInst::ICMP_UGT && "ICmp should be folded!"
) ? static_cast<void> (0) : __assert_fail ("ICmp.getPredicate() == ICmpInst::ICMP_UGT && \"ICmp should be folded!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4386, __PRETTY_FUNCTION__));
return new ICmpInst(CmpInst::ICMP_SLT, X, Constant::getNullValue(SrcTy));
4388}

4390/// Handle icmp (cast x), (cast or constant).
4391Instruction *InstCombiner::foldICmpWithCastOp(ICmpInst &ICmp) {
auto *CastOp0 = dyn_cast<CastInst>(ICmp.getOperand(0));
if (!CastOp0)
  return nullptr;
if (!isa<Constant>(ICmp.getOperand(1)) && !isa<CastInst>(ICmp.getOperand(1)))
  return nullptr;

Value *Op0Src = CastOp0->getOperand(0);
Type *SrcTy = CastOp0->getSrcTy();
Type *DestTy = CastOp0->getDestTy();

// Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the
// integer type is the same size as the pointer type.
auto CompatibleSizes = [&](Type *SrcTy, Type *DestTy) {
  if (isa<VectorType>(SrcTy)) {
    SrcTy = cast<VectorType>(SrcTy)->getElementType();
    DestTy = cast<VectorType>(DestTy)->getElementType();
  }
  return DL.getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth();
};
if (CastOp0->getOpcode() == Instruction::PtrToInt &&
    CompatibleSizes(SrcTy, DestTy)) {
  Value *NewOp1 = nullptr;
  if (auto *PtrToIntOp1 = dyn_cast<PtrToIntOperator>(ICmp.getOperand(1))) {
    Value *PtrSrc = PtrToIntOp1->getOperand(0);
    if (PtrSrc->getType()->getPointerAddressSpace() ==
        Op0Src->getType()->getPointerAddressSpace()) {
      NewOp1 = PtrToIntOp1->getOperand(0);
      // If the pointer types don't match, insert a bitcast.
      if (Op0Src->getType() != NewOp1->getType())
        NewOp1 = Builder.CreateBitCast(NewOp1, Op0Src->getType());
    }
  } else if (auto *RHSC = dyn_cast<Constant>(ICmp.getOperand(1))) {
    NewOp1 = ConstantExpr::getIntToPtr(RHSC, SrcTy);
  }

  if (NewOp1)
    return new ICmpInst(ICmp.getPredicate(), Op0Src, NewOp1);
}

return foldICmpWithZextOrSext(ICmp, Builder);
4432}

4434static bool isNeutralValue(Instruction::BinaryOps BinaryOp, Value *RHS) {
switch (BinaryOp) {
  default:
    llvm_unreachable("Unsupported binary op")::llvm::llvm_unreachable_internal("Unsupported binary op", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4437);
  case Instruction::Add:
  case Instruction::Sub:
    return match(RHS, m_Zero());
  case Instruction::Mul:
    return match(RHS, m_One());
}
4444}

4446OverflowResult InstCombiner::computeOverflow(
  Instruction::BinaryOps BinaryOp, bool IsSigned,
  Value *LHS, Value *RHS, Instruction *CxtI) const {
switch (BinaryOp) {
  default:
    llvm_unreachable("Unsupported binary op")::llvm::llvm_unreachable_internal("Unsupported binary op", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4451);
  case Instruction::Add:
    if (IsSigned)
      return computeOverflowForSignedAdd(LHS, RHS, CxtI);
    else
      return computeOverflowForUnsignedAdd(LHS, RHS, CxtI);
  case Instruction::Sub:
    if (IsSigned)
      return computeOverflowForSignedSub(LHS, RHS, CxtI);
    else
      return computeOverflowForUnsignedSub(LHS, RHS, CxtI);
  case Instruction::Mul:
    if (IsSigned)
      return computeOverflowForSignedMul(LHS, RHS, CxtI);
    else
      return computeOverflowForUnsignedMul(LHS, RHS, CxtI);
}
4468}

4470bool InstCombiner::OptimizeOverflowCheck(
  Instruction::BinaryOps BinaryOp, bool IsSigned, Value *LHS, Value *RHS,
  Instruction &OrigI, Value *&Result, Constant *&Overflow) {
if (OrigI.isCommutative() && isa<Constant>(LHS) && !isa<Constant>(RHS))
  std::swap(LHS, RHS);

// If the overflow check was an add followed by a compare, the insertion point
// may be pointing to the compare.  We want to insert the new instructions
// before the add in case there are uses of the add between the add and the
// compare.
Builder.SetInsertPoint(&OrigI);

if (isNeutralValue(BinaryOp, RHS)) {
  Result = LHS;
  Overflow = Builder.getFalse();
  return true;
}

switch (computeOverflow(BinaryOp, IsSigned, LHS, RHS, &OrigI)) {
  case OverflowResult::MayOverflow:
    return false;
  case OverflowResult::AlwaysOverflowsLow:
  case OverflowResult::AlwaysOverflowsHigh:
    Result = Builder.CreateBinOp(BinaryOp, LHS, RHS);
    Result->takeName(&OrigI);
    Overflow = Builder.getTrue();
    return true;
  case OverflowResult::NeverOverflows:
    Result = Builder.CreateBinOp(BinaryOp, LHS, RHS);
    Result->takeName(&OrigI);
    Overflow = Builder.getFalse();
    if (auto *Inst = dyn_cast<Instruction>(Result)) {
      if (IsSigned)
        Inst->setHasNoSignedWrap();
      else
        Inst->setHasNoUnsignedWrap();
    }
    return true;
}

llvm_unreachable("Unexpected overflow result")::llvm::llvm_unreachable_internal("Unexpected overflow result"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4510);
4511}

4513/// Recognize and process idiom involving test for multiplication
4514/// overflow.
4515///
4516/// The caller has matched a pattern of the form:
4517///   I = cmp u (mul(zext A, zext B), V
4518/// The function checks if this is a test for overflow and if so replaces
4519/// multiplication with call to 'mul.with.overflow' intrinsic.
4520///
4521/// \param I Compare instruction.
4522/// \param MulVal Result of 'mult' instruction.  It is one of the arguments of
4523///               the compare instruction.  Must be of integer type.
4524/// \param OtherVal The other argument of compare instruction.
4525/// \returns Instruction which must replace the compare instruction, NULL if no
4526///          replacement required.
4527static Instruction *processUMulZExtIdiom(ICmpInst &I, Value *MulVal,
                                       Value *OtherVal, InstCombiner &IC) {
// Don't bother doing this transformation for pointers, don't do it for
// vectors.
if (!isa<IntegerType>(MulVal->getType()))
  return nullptr;

assert(I.getOperand(0) == MulVal || I.getOperand(1) == MulVal)((I.getOperand(0) == MulVal || I.getOperand(1) == MulVal) ? static_cast
<void> (0) : __assert_fail ("I.getOperand(0) == MulVal || I.getOperand(1) == MulVal"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4534, __PRETTY_FUNCTION__));
assert(I.getOperand(0) == OtherVal || I.getOperand(1) == OtherVal)((I.getOperand(0) == OtherVal || I.getOperand(1) == OtherVal)
 ? static_cast<void> (0) : __assert_fail ("I.getOperand(0) == OtherVal || I.getOperand(1) == OtherVal"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4535, __PRETTY_FUNCTION__));
auto *MulInstr = dyn_cast<Instruction>(MulVal);
if (!MulInstr)
  return nullptr;
assert(MulInstr->getOpcode() == Instruction::Mul)((MulInstr->getOpcode() == Instruction::Mul) ? static_cast
<void> (0) : __assert_fail ("MulInstr->getOpcode() == Instruction::Mul"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4539, __PRETTY_FUNCTION__));

auto *LHS = cast<ZExtOperator>(MulInstr->getOperand(0)),
     *RHS = cast<ZExtOperator>(MulInstr->getOperand(1));
assert(LHS->getOpcode() == Instruction::ZExt)((LHS->getOpcode() == Instruction::ZExt) ? static_cast<
void> (0) : __assert_fail ("LHS->getOpcode() == Instruction::ZExt"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4543, __PRETTY_FUNCTION__));
assert(RHS->getOpcode() == Instruction::ZExt)((RHS->getOpcode() == Instruction::ZExt) ? static_cast<
void> (0) : __assert_fail ("RHS->getOpcode() == Instruction::ZExt"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4544, __PRETTY_FUNCTION__));
Value *A = LHS->getOperand(0), *B = RHS->getOperand(0);

// Calculate type and width of the result produced by mul.with.overflow.
Type *TyA = A->getType(), *TyB = B->getType();
unsigned WidthA = TyA->getPrimitiveSizeInBits(),
         WidthB = TyB->getPrimitiveSizeInBits();
unsigned MulWidth;
Type *MulType;
if (WidthB > WidthA) {
  MulWidth = WidthB;
  MulType = TyB;
} else {
  MulWidth = WidthA;
  MulType = TyA;
}

// In order to replace the original mul with a narrower mul.with.overflow,
// all uses must ignore upper bits of the product.  The number of used low
// bits must be not greater than the width of mul.with.overflow.
if (MulVal->hasNUsesOrMore(2))
  for (User *U : MulVal->users()) {
    if (U == &I)
      continue;
    if (TruncInst *TI = dyn_cast<TruncInst>(U)) {
      // Check if truncation ignores bits above MulWidth.
      unsigned TruncWidth = TI->getType()->getPrimitiveSizeInBits();
      if (TruncWidth > MulWidth)
        return nullptr;
    } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U)) {
      // Check if AND ignores bits above MulWidth.
      if (BO->getOpcode() != Instruction::And)
        return nullptr;
      if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1))) {
        const APInt &CVal = CI->getValue();
        if (CVal.getBitWidth() - CVal.countLeadingZeros() > MulWidth)
          return nullptr;
      } else {
        // In this case we could have the operand of the binary operation
        // being defined in another block, and performing the replacement
        // could break the dominance relation.
        return nullptr;
      }
    } else {
      // Other uses prohibit this transformation.
      return nullptr;
    }
  }

// Recognize patterns
switch (I.getPredicate()) {
case ICmpInst::ICMP_EQ:
case ICmpInst::ICMP_NE:
  // Recognize pattern:
  //   mulval = mul(zext A, zext B)
  //   cmp eq/neq mulval, zext trunc mulval
  if (ZExtInst *Zext = dyn_cast<ZExtInst>(OtherVal))
    if (Zext->hasOneUse()) {
      Value *ZextArg = Zext->getOperand(0);
      if (TruncInst *Trunc = dyn_cast<TruncInst>(ZextArg))
        if (Trunc->getType()->getPrimitiveSizeInBits() == MulWidth)
          break; //Recognized
    }

  // Recognize pattern:
  //   mulval = mul(zext A, zext B)
  //   cmp eq/neq mulval, and(mulval, mask), mask selects low MulWidth bits.
  ConstantInt *CI;
  Value *ValToMask;
  if (match(OtherVal, m_And(m_Value(ValToMask), m_ConstantInt(CI)))) {
    if (ValToMask != MulVal)
      return nullptr;
    const APInt &CVal = CI->getValue() + 1;
    if (CVal.isPowerOf2()) {
      unsigned MaskWidth = CVal.logBase2();
      if (MaskWidth == MulWidth)
        break; // Recognized
    }
  }
  return nullptr;

case ICmpInst::ICMP_UGT:
  // Recognize pattern:
  //   mulval = mul(zext A, zext B)
  //   cmp ugt mulval, max
  if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
    APInt MaxVal = APInt::getMaxValue(MulWidth);
    MaxVal = MaxVal.zext(CI->getBitWidth());
    if (MaxVal.eq(CI->getValue()))
      break; // Recognized
  }
  return nullptr;

case ICmpInst::ICMP_UGE:
  // Recognize pattern:
  //   mulval = mul(zext A, zext B)
  //   cmp uge mulval, max+1
  if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
    APInt MaxVal = APInt::getOneBitSet(CI->getBitWidth(), MulWidth);
    if (MaxVal.eq(CI->getValue()))
      break; // Recognized
  }
  return nullptr;

case ICmpInst::ICMP_ULE:
  // Recognize pattern:
  //   mulval = mul(zext A, zext B)
  //   cmp ule mulval, max
  if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
    APInt MaxVal = APInt::getMaxValue(MulWidth);
    MaxVal = MaxVal.zext(CI->getBitWidth());
    if (MaxVal.eq(CI->getValue()))
      break; // Recognized
  }
  return nullptr;

case ICmpInst::ICMP_ULT:
  // Recognize pattern:
  //   mulval = mul(zext A, zext B)
  //   cmp ule mulval, max + 1
  if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)) {
    APInt MaxVal = APInt::getOneBitSet(CI->getBitWidth(), MulWidth);
    if (MaxVal.eq(CI->getValue()))
      break; // Recognized
  }
  return nullptr;

default:
  return nullptr;
}

InstCombiner::BuilderTy &Builder = IC.Builder;
Builder.SetInsertPoint(MulInstr);

// Replace: mul(zext A, zext B) --> mul.with.overflow(A, B)
Value *MulA = A, *MulB = B;
if (WidthA < MulWidth)
  MulA = Builder.CreateZExt(A, MulType);
if (WidthB < MulWidth)
  MulB = Builder.CreateZExt(B, MulType);
Function *F = Intrinsic::getDeclaration(
    I.getModule(), Intrinsic::umul_with_overflow, MulType);
CallInst *Call = Builder.CreateCall(F, {MulA, MulB}, "umul");
IC.Worklist.Add(MulInstr);

// If there are uses of mul result other than the comparison, we know that
// they are truncation or binary AND. Change them to use result of
// mul.with.overflow and adjust properly mask/size.
if (MulVal->hasNUsesOrMore(2)) {
  Value *Mul = Builder.CreateExtractValue(Call, 0, "umul.value");
  for (auto UI = MulVal->user_begin(), UE = MulVal->user_end(); UI != UE;) {
    User *U = *UI++;
    if (U == &I || U == OtherVal)
      continue;
    if (TruncInst *TI = dyn_cast<TruncInst>(U)) {
      if (TI->getType()->getPrimitiveSizeInBits() == MulWidth)
        IC.replaceInstUsesWith(*TI, Mul);
      else
        TI->setOperand(0, Mul);
    } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U)) {
      assert(BO->getOpcode() == Instruction::And)((BO->getOpcode() == Instruction::And) ? static_cast<void
> (0) : __assert_fail ("BO->getOpcode() == Instruction::And"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4704, __PRETTY_FUNCTION__));
      // Replace (mul & mask) --> zext (mul.with.overflow & short_mask)
      ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));
      APInt ShortMask = CI->getValue().trunc(MulWidth);
      Value *ShortAnd = Builder.CreateAnd(Mul, ShortMask);
      Instruction *Zext =
          cast<Instruction>(Builder.CreateZExt(ShortAnd, BO->getType()));
      IC.Worklist.Add(Zext);
      IC.replaceInstUsesWith(*BO, Zext);
    } else {
      llvm_unreachable("Unexpected Binary operation")::llvm::llvm_unreachable_internal("Unexpected Binary operation"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4714);
    }
    IC.Worklist.Add(cast<Instruction>(U));
  }
}
if (isa<Instruction>(OtherVal))
  IC.Worklist.Add(cast<Instruction>(OtherVal));

// The original icmp gets replaced with the overflow value, maybe inverted
// depending on predicate.
bool Inverse = false;
switch (I.getPredicate()) {
case ICmpInst::ICMP_NE:
  break;
case ICmpInst::ICMP_EQ:
  Inverse = true;
  break;
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE:
  if (I.getOperand(0) == MulVal)
    break;
  Inverse = true;
  break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
  if (I.getOperand(1) == MulVal)
    break;
  Inverse = true;
  break;
default:
  llvm_unreachable("Unexpected predicate")::llvm::llvm_unreachable_internal("Unexpected predicate", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4744);
}
if (Inverse) {
  Value *Res = Builder.CreateExtractValue(Call, 1);
  return BinaryOperator::CreateNot(Res);
}

return ExtractValueInst::Create(Call, 1);
4752}

4754/// When performing a comparison against a constant, it is possible that not all
4755/// the bits in the LHS are demanded. This helper method computes the mask that
4756/// IS demanded.
4757static APInt getDemandedBitsLHSMask(ICmpInst &I, unsigned BitWidth) {
const APInt *RHS;
if (!match(I.getOperand(1), m_APInt(RHS)))
  return APInt::getAllOnesValue(BitWidth);

// If this is a normal comparison, it demands all bits. If it is a sign bit
// comparison, it only demands the sign bit.
bool UnusedBit;
if (isSignBitCheck(I.getPredicate(), *RHS, UnusedBit))
  return APInt::getSignMask(BitWidth);

switch (I.getPredicate()) {
// For a UGT comparison, we don't care about any bits that
// correspond to the trailing ones of the comparand.  The value of these
// bits doesn't impact the outcome of the comparison, because any value
// greater than the RHS must differ in a bit higher than these due to carry.
case ICmpInst::ICMP_UGT:
  return APInt::getBitsSetFrom(BitWidth, RHS->countTrailingOnes());

// Similarly, for a ULT comparison, we don't care about the trailing zeros.
// Any value less than the RHS must differ in a higher bit because of carries.
case ICmpInst::ICMP_ULT:
  return APInt::getBitsSetFrom(BitWidth, RHS->countTrailingZeros());

default:
  return APInt::getAllOnesValue(BitWidth);
}
4784}

4786/// Check if the order of \p Op0 and \p Op1 as operands in an ICmpInst
4787/// should be swapped.
4788/// The decision is based on how many times these two operands are reused
4789/// as subtract operands and their positions in those instructions.
4790/// The rationale is that several architectures use the same instruction for
4791/// both subtract and cmp. Thus, it is better if the order of those operands
4792/// match.
4793/// \return true if Op0 and Op1 should be swapped.
4794static bool swapMayExposeCSEOpportunities(const Value *Op0, const Value *Op1) {
// Filter out pointer values as those cannot appear directly in subtract.
// FIXME: we may want to go through inttoptrs or bitcasts.
if (Op0->getType()->isPointerTy())
  return false;
// If a subtract already has the same operands as a compare, swapping would be
// bad. If a subtract has the same operands as a compare but in reverse order,
// then swapping is good.
int GoodToSwap = 0;
for (const User *U : Op0->users()) {
  if (match(U, m_Sub(m_Specific(Op1), m_Specific(Op0))))
    GoodToSwap++;
  else if (match(U, m_Sub(m_Specific(Op0), m_Specific(Op1))))
    GoodToSwap--;
}
return GoodToSwap > 0;
4810}

4812/// Check that one use is in the same block as the definition and all
4813/// other uses are in blocks dominated by a given block.
4814///
4815/// \param DI Definition
4816/// \param UI Use
4817/// \param DB Block that must dominate all uses of \p DI outside
4818///           the parent block
4819/// \return true when \p UI is the only use of \p DI in the parent block
4820/// and all other uses of \p DI are in blocks dominated by \p DB.
4821///
4822bool InstCombiner::dominatesAllUses(const Instruction *DI,
                                  const Instruction *UI,
                                  const BasicBlock *DB) const {
assert(DI && UI && "Instruction not defined\n")((DI && UI && "Instruction not defined\n") ? static_cast
<void> (0) : __assert_fail ("DI && UI && \"Instruction not defined\\n\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4825, __PRETTY_FUNCTION__));
// Ignore incomplete definitions.
if (!DI->getParent())
  return false;
// DI and UI must be in the same block.
if (DI->getParent() != UI->getParent())
  return false;
// Protect from self-referencing blocks.
if (DI->getParent() == DB)
  return false;
for (const User *U : DI->users()) {
  auto *Usr = cast<Instruction>(U);
  if (Usr != UI && !DT.dominates(DB, Usr->getParent()))
    return false;
}
return true;
4841}

4843/// Return true when the instruction sequence within a block is select-cmp-br.
4844static bool isChainSelectCmpBranch(const SelectInst *SI) {
const BasicBlock *BB = SI->getParent();
if (!BB)
  return false;
auto *BI = dyn_cast_or_null<BranchInst>(BB->getTerminator());
if (!BI || BI->getNumSuccessors() != 2)
  return false;
auto *IC = dyn_cast<ICmpInst>(BI->getCondition());
if (!IC || (IC->getOperand(0) != SI && IC->getOperand(1) != SI))
  return false;
return true;
4855}

4857/// True when a select result is replaced by one of its operands
4858/// in select-icmp sequence. This will eventually result in the elimination
4859/// of the select.
4860///
4861/// \param SI    Select instruction
4862/// \param Icmp  Compare instruction
4863/// \param SIOpd Operand that replaces the select
4864///
4865/// Notes:
4866/// - The replacement is global and requires dominator information
4867/// - The caller is responsible for the actual replacement
4868///
4869/// Example:
4870///
4871/// entry:
4872///  %4 = select i1 %3, %C* %0, %C* null
4873///  %5 = icmp eq %C* %4, null
4874///  br i1 %5, label %9, label %7
4875///  ...
4876///  ; <label>:7                                       ; preds = %entry
4877///  %8 = getelementptr inbounds %C* %4, i64 0, i32 0
4878///  ...
4879///
4880/// can be transformed to
4881///
4882///  %5 = icmp eq %C* %0, null
4883///  %6 = select i1 %3, i1 %5, i1 true
4884///  br i1 %6, label %9, label %7
4885///  ...
4886///  ; <label>:7                                       ; preds = %entry
4887///  %8 = getelementptr inbounds %C* %0, i64 0, i32 0  // replace by %0!
4888///
4889/// Similar when the first operand of the select is a constant or/and
4890/// the compare is for not equal rather than equal.
4891///
4892/// NOTE: The function is only called when the select and compare constants
4893/// are equal, the optimization can work only for EQ predicates. This is not a
4894/// major restriction since a NE compare should be 'normalized' to an equal
4895/// compare, which usually happens in the combiner and test case
4896/// select-cmp-br.ll checks for it.
4897bool InstCombiner::replacedSelectWithOperand(SelectInst *SI,
                                           const ICmpInst *Icmp,
                                           const unsigned SIOpd) {
assert((SIOpd == 1 || SIOpd == 2) && "Invalid select operand!")(((SIOpd == 1 || SIOpd == 2) && "Invalid select operand!"
) ? static_cast<void> (0) : __assert_fail ("(SIOpd == 1 || SIOpd == 2) && \"Invalid select operand!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4900, __PRETTY_FUNCTION__));
if (isChainSelectCmpBranch(SI) && Icmp->getPredicate() == ICmpInst::ICMP_EQ) {
  BasicBlock *Succ = SI->getParent()->getTerminator()->getSuccessor(1);
  // The check for the single predecessor is not the best that can be
  // done. But it protects efficiently against cases like when SI's
  // home block has two successors, Succ and Succ1, and Succ1 predecessor
  // of Succ. Then SI can't be replaced by SIOpd because the use that gets
  // replaced can be reached on either path. So the uniqueness check
  // guarantees that the path all uses of SI (outside SI's parent) are on
  // is disjoint from all other paths out of SI. But that information
  // is more expensive to compute, and the trade-off here is in favor
  // of compile-time. It should also be noticed that we check for a single
  // predecessor and not only uniqueness. This to handle the situation when
  // Succ and Succ1 points to the same basic block.
  if (Succ->getSinglePredecessor() && dominatesAllUses(SI, Icmp, Succ)) {
    NumSel++;
    SI->replaceUsesOutsideBlock(SI->getOperand(SIOpd), SI->getParent());
    return true;
  }
}
return false;
4921}

4923/// Try to fold the comparison based on range information we can get by checking
4924/// whether bits are known to be zero or one in the inputs.
4925Instruction *InstCombiner::foldICmpUsingKnownBits(ICmpInst &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Type *Ty = Op0->getType();
ICmpInst::Predicate Pred = I.getPredicate();

// Get scalar or pointer size.
unsigned BitWidth = Ty->isIntOrIntVectorTy()
                        ? Ty->getScalarSizeInBits()
                        : DL.getPointerTypeSizeInBits(Ty->getScalarType());

if (!BitWidth)
  return nullptr;

KnownBits Op0Known(BitWidth);
KnownBits Op1Known(BitWidth);

if (SimplifyDemandedBits(&I, 0,
                         getDemandedBitsLHSMask(I, BitWidth),
                         Op0Known, 0))
  return &I;

if (SimplifyDemandedBits(&I, 1, APInt::getAllOnesValue(BitWidth),
                         Op1Known, 0))
  return &I;

// Given the known and unknown bits, compute a range that the LHS could be
// in.  Compute the Min, Max and RHS values based on the known bits. For the
// EQ and NE we use unsigned values.
APInt Op0Min(BitWidth, 0), Op0Max(BitWidth, 0);
APInt Op1Min(BitWidth, 0), Op1Max(BitWidth, 0);
if (I.isSigned()) {
  computeSignedMinMaxValuesFromKnownBits(Op0Known, Op0Min, Op0Max);
  computeSignedMinMaxValuesFromKnownBits(Op1Known, Op1Min, Op1Max);
} else {
  computeUnsignedMinMaxValuesFromKnownBits(Op0Known, Op0Min, Op0Max);
  computeUnsignedMinMaxValuesFromKnownBits(Op1Known, Op1Min, Op1Max);
}

// If Min and Max are known to be the same, then SimplifyDemandedBits figured
// out that the LHS or RHS is a constant. Constant fold this now, so that
// code below can assume that Min != Max.
if (!isa<Constant>(Op0) && Op0Min == Op0Max)
  return new ICmpInst(Pred, ConstantExpr::getIntegerValue(Ty, Op0Min), Op1);
if (!isa<Constant>(Op1) && Op1Min == Op1Max)
  return new ICmpInst(Pred, Op0, ConstantExpr::getIntegerValue(Ty, Op1Min));

// Based on the range information we know about the LHS, see if we can
// simplify this comparison.  For example, (x&4) < 8 is always true.
switch (Pred) {
default:
  llvm_unreachable("Unknown icmp opcode!")::llvm::llvm_unreachable_internal("Unknown icmp opcode!", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4975);
case ICmpInst::ICMP_EQ:
case ICmpInst::ICMP_NE: {
  if (Op0Max.ult(Op1Min) || Op0Min.ugt(Op1Max)) {
    return Pred == CmpInst::ICMP_EQ
               ? replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()))
               : replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  }

  // If all bits are known zero except for one, then we know at most one bit
  // is set. If the comparison is against zero, then this is a check to see if
  // *that* bit is set.
  APInt Op0KnownZeroInverted = ~Op0Known.Zero;
  if (Op1Known.isZero()) {
    // If the LHS is an AND with the same constant, look through it.
    Value *LHS = nullptr;
    const APInt *LHSC;
    if (!match(Op0, m_And(m_Value(LHS), m_APInt(LHSC))) ||
        *LHSC != Op0KnownZeroInverted)
      LHS = Op0;

    Value *X;
    if (match(LHS, m_Shl(m_One(), m_Value(X)))) {
      APInt ValToCheck = Op0KnownZeroInverted;
      Type *XTy = X->getType();
      if (ValToCheck.isPowerOf2()) {
        // ((1 << X) & 8) == 0 -> X != 3
        // ((1 << X) & 8) != 0 -> X == 3
        auto *CmpC = ConstantInt::get(XTy, ValToCheck.countTrailingZeros());
        auto NewPred = ICmpInst::getInversePredicate(Pred);
        return new ICmpInst(NewPred, X, CmpC);
      } else if ((++ValToCheck).isPowerOf2()) {
        // ((1 << X) & 7) == 0 -> X >= 3
        // ((1 << X) & 7) != 0 -> X  < 3
        auto *CmpC = ConstantInt::get(XTy, ValToCheck.countTrailingZeros());
        auto NewPred =
            Pred == CmpInst::ICMP_EQ ? CmpInst::ICMP_UGE : CmpInst::ICMP_ULT;
        return new ICmpInst(NewPred, X, CmpC);
      }
    }

    // Check if the LHS is 8 >>u x and the result is a power of 2 like 1.
    const APInt *CI;
    if (Op0KnownZeroInverted.isOneValue() &&
        match(LHS, m_LShr(m_Power2(CI), m_Value(X)))) {
      // ((8 >>u X) & 1) == 0 -> X != 3
      // ((8 >>u X) & 1) != 0 -> X == 3
      unsigned CmpVal = CI->countTrailingZeros();
      auto NewPred = ICmpInst::getInversePredicate(Pred);
      return new ICmpInst(NewPred, X, ConstantInt::get(X->getType(), CmpVal));
    }
  }
  break;
}
case ICmpInst::ICMP_ULT: {
  if (Op0Max.ult(Op1Min)) // A <u B -> true if max(A) < min(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Min.uge(Op1Max)) // A <u B -> false if min(A) >= max(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Min == Op0Max) // A <u B -> A != B if max(A) == min(B)
    return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);

  const APInt *CmpC;
  if (match(Op1, m_APInt(CmpC))) {
    // A <u C -> A == C-1 if min(A)+1 == C
    if (*CmpC == Op0Min + 1)
      return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
                          ConstantInt::get(Op1->getType(), *CmpC - 1));
    // X <u C --> X == 0, if the number of zero bits in the bottom of X
    // exceeds the log2 of C.
    if (Op0Known.countMinTrailingZeros() >= CmpC->ceilLogBase2())
      return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
                          Constant::getNullValue(Op1->getType()));
  }
  break;
}
case ICmpInst::ICMP_UGT: {
  if (Op0Min.ugt(Op1Max)) // A >u B -> true if min(A) > max(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Max.ule(Op1Min)) // A >u B -> false if max(A) <= max(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Max == Op0Min) // A >u B -> A != B if min(A) == max(B)
    return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);

  const APInt *CmpC;
  if (match(Op1, m_APInt(CmpC))) {
    // A >u C -> A == C+1 if max(a)-1 == C
    if (*CmpC == Op0Max - 1)
      return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
                          ConstantInt::get(Op1->getType(), *CmpC + 1));
    // X >u C --> X != 0, if the number of zero bits in the bottom of X
    // exceeds the log2 of C.
    if (Op0Known.countMinTrailingZeros() >= CmpC->getActiveBits())
      return new ICmpInst(ICmpInst::ICMP_NE, Op0,
                          Constant::getNullValue(Op1->getType()));
  }
  break;
}
case ICmpInst::ICMP_SLT: {
  if (Op0Max.slt(Op1Min)) // A <s B -> true if max(A) < min(C)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Min.sge(Op1Max)) // A <s B -> false if min(A) >= max(C)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Min == Op0Max) // A <s B -> A != B if max(A) == min(B)
    return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
  const APInt *CmpC;
  if (match(Op1, m_APInt(CmpC))) {
    if (*CmpC == Op0Min + 1) // A <s C -> A == C-1 if min(A)+1 == C
      return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
                          ConstantInt::get(Op1->getType(), *CmpC - 1));
  }
  break;
}
case ICmpInst::ICMP_SGT: {
  if (Op0Min.sgt(Op1Max)) // A >s B -> true if min(A) > max(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Max.sle(Op1Min)) // A >s B -> false if max(A) <= min(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Max == Op0Min) // A >s B -> A != B if min(A) == max(B)
    return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
  const APInt *CmpC;
  if (match(Op1, m_APInt(CmpC))) {
    if (*CmpC == Op0Max - 1) // A >s C -> A == C+1 if max(A)-1 == C
      return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
                          ConstantInt::get(Op1->getType(), *CmpC + 1));
  }
  break;
}
case ICmpInst::ICMP_SGE:
  assert(!isa<ConstantInt>(Op1) && "ICMP_SGE with ConstantInt not folded!")((!isa<ConstantInt>(Op1) && "ICMP_SGE with ConstantInt not folded!"
) ? static_cast<void> (0) : __assert_fail ("!isa<ConstantInt>(Op1) && \"ICMP_SGE with ConstantInt not folded!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5104, __PRETTY_FUNCTION__));
  if (Op0Min.sge(Op1Max)) // A >=s B -> true if min(A) >= max(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Max.slt(Op1Min)) // A >=s B -> false if max(A) < min(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Min == Op0Max) // A >=s B -> A == B if max(A) == min(B)
    return new ICmpInst(ICmpInst::ICMP_EQ, Op0, Op1);
  break;
case ICmpInst::ICMP_SLE:
  assert(!isa<ConstantInt>(Op1) && "ICMP_SLE with ConstantInt not folded!")((!isa<ConstantInt>(Op1) && "ICMP_SLE with ConstantInt not folded!"
) ? static_cast<void> (0) : __assert_fail ("!isa<ConstantInt>(Op1) && \"ICMP_SLE with ConstantInt not folded!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5113, __PRETTY_FUNCTION__));
  if (Op0Max.sle(Op1Min)) // A <=s B -> true if max(A) <= min(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Min.sgt(Op1Max)) // A <=s B -> false if min(A) > max(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Max == Op0Min) // A <=s B -> A == B if min(A) == max(B)
    return new ICmpInst(ICmpInst::ICMP_EQ, Op0, Op1);
  break;
case ICmpInst::ICMP_UGE:
  assert(!isa<ConstantInt>(Op1) && "ICMP_UGE with ConstantInt not folded!")((!isa<ConstantInt>(Op1) && "ICMP_UGE with ConstantInt not folded!"
) ? static_cast<void> (0) : __assert_fail ("!isa<ConstantInt>(Op1) && \"ICMP_UGE with ConstantInt not folded!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5122, __PRETTY_FUNCTION__));
  if (Op0Min.uge(Op1Max)) // A >=u B -> true if min(A) >= max(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Max.ult(Op1Min)) // A >=u B -> false if max(A) < min(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Min == Op0Max) // A >=u B -> A == B if max(A) == min(B)
    return new ICmpInst(ICmpInst::ICMP_EQ, Op0, Op1);
  break;
case ICmpInst::ICMP_ULE:
  assert(!isa<ConstantInt>(Op1) && "ICMP_ULE with ConstantInt not folded!")((!isa<ConstantInt>(Op1) && "ICMP_ULE with ConstantInt not folded!"
) ? static_cast<void> (0) : __assert_fail ("!isa<ConstantInt>(Op1) && \"ICMP_ULE with ConstantInt not folded!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5131, __PRETTY_FUNCTION__));
  if (Op0Max.ule(Op1Min)) // A <=u B -> true if max(A) <= min(B)
    return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
  if (Op0Min.ugt(Op1Max)) // A <=u B -> false if min(A) > max(B)
    return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
  if (Op1Max == Op0Min) // A <=u B -> A == B if min(A) == max(B)
    return new ICmpInst(ICmpInst::ICMP_EQ, Op0, Op1);
  break;
}

// Turn a signed comparison into an unsigned one if both operands are known to
// have the same sign.
if (I.isSigned() &&
    ((Op0Known.Zero.isNegative() && Op1Known.Zero.isNegative()) ||
     (Op0Known.One.isNegative() && Op1Known.One.isNegative())))
  return new ICmpInst(I.getUnsignedPredicate(), Op0, Op1);

return nullptr;
5149}

5151llvm::Optional<std::pair<CmpInst::Predicate, Constant *>>
5152llvm::getFlippedStrictnessPredicateAndConstant(CmpInst::Predicate Pred,
                                             Constant *C) {
assert(ICmpInst::isRelational(Pred) && ICmpInst::isIntPredicate(Pred) &&((ICmpInst::isRelational(Pred) && ICmpInst::isIntPredicate
(Pred) && "Only for relational integer predicates.") ?
 static_cast<void> (0) : __assert_fail ("ICmpInst::isRelational(Pred) && ICmpInst::isIntPredicate(Pred) && \"Only for relational integer predicates.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5155, __PRETTY_FUNCTION__))
       "Only for relational integer predicates.")((ICmpInst::isRelational(Pred) && ICmpInst::isIntPredicate
(Pred) && "Only for relational integer predicates.") ?
 static_cast<void> (0) : __assert_fail ("ICmpInst::isRelational(Pred) && ICmpInst::isIntPredicate(Pred) && \"Only for relational integer predicates.\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5155, __PRETTY_FUNCTION__));

Type *Type = C->getType();
bool IsSigned = ICmpInst::isSigned(Pred);

CmpInst::Predicate UnsignedPred = ICmpInst::getUnsignedPredicate(Pred);
bool WillIncrement =
    UnsignedPred == ICmpInst::ICMP_ULE || UnsignedPred == ICmpInst::ICMP_UGT;

// Check if the constant operand can be safely incremented/decremented
// without overflowing/underflowing.
auto ConstantIsOk = [WillIncrement, IsSigned](ConstantInt *C) {
  return WillIncrement ? !C->isMaxValue(IsSigned) : !C->isMinValue(IsSigned);
};

Constant *SafeReplacementConstant = nullptr;
if (auto *CI = dyn_cast<ConstantInt>(C)) {
  // Bail out if the constant can't be safely incremented/decremented.
  if (!ConstantIsOk(CI))
    return llvm::None;
} else if (Type->isVectorTy()) {
  unsigned NumElts = Type->getVectorNumElements();
  for (unsigned i = 0; i != NumElts; ++i) {
    Constant *Elt = C->getAggregateElement(i);
    if (!Elt)
      return llvm::None;

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

    // Bail out if we can't determine if this constant is min/max or if we
    // know that this constant is min/max.
    auto *CI = dyn_cast<ConstantInt>(Elt);
    if (!CI || !ConstantIsOk(CI))
      return llvm::None;

    if (!SafeReplacementConstant)
      SafeReplacementConstant = CI;
  }
} else {
  // ConstantExpr?
  return llvm::None;
}

// It may not be safe to change a compare predicate in the presence of
// undefined elements, so replace those elements with the first safe constant
// that we found.
if (C->containsUndefElement()) {
  assert(SafeReplacementConstant && "Replacement constant not set")((SafeReplacementConstant && "Replacement constant not set"
) ? static_cast<void> (0) : __assert_fail ("SafeReplacementConstant && \"Replacement constant not set\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5203, __PRETTY_FUNCTION__));
  C = Constant::replaceUndefsWith(C, SafeReplacementConstant);
}

CmpInst::Predicate NewPred = CmpInst::getFlippedStrictnessPredicate(Pred);

// Increment or decrement the constant.
Constant *OneOrNegOne = ConstantInt::get(Type, WillIncrement ? 1 : -1, true);
Constant *NewC = ConstantExpr::getAdd(C, OneOrNegOne);

return std::make_pair(NewPred, NewC);
5214}

5216/// If we have an icmp le or icmp ge instruction with a constant operand, turn
5217/// it into the appropriate icmp lt or icmp gt instruction. This transform
5218/// allows them to be folded in visitICmpInst.
5219static ICmpInst *canonicalizeCmpWithConstant(ICmpInst &I) {
ICmpInst::Predicate Pred = I.getPredicate();
if (ICmpInst::isEquality(Pred) || !ICmpInst::isIntPredicate(Pred) ||
    isCanonicalPredicate(Pred))
  return nullptr;

Value *Op0 = I.getOperand(0);
Value *Op1 = I.getOperand(1);
auto *Op1C = dyn_cast<Constant>(Op1);
if (!Op1C)
  return nullptr;

auto FlippedStrictness = getFlippedStrictnessPredicateAndConstant(Pred, Op1C);
if (!FlippedStrictness)
  return nullptr;

return new ICmpInst(FlippedStrictness->first, Op0, FlippedStrictness->second);
5236}

5238/// Integer compare with boolean values can always be turned into bitwise ops.
5239static Instruction *canonicalizeICmpBool(ICmpInst &I,
                                       InstCombiner::BuilderTy &Builder) {
Value *A = I.getOperand(0), *B = I.getOperand(1);
assert(A->getType()->isIntOrIntVectorTy(1) && "Bools only")((A->getType()->isIntOrIntVectorTy(1) && "Bools only"
) ? static_cast<void> (0) : __assert_fail ("A->getType()->isIntOrIntVectorTy(1) && \"Bools only\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5242, __PRETTY_FUNCTION__));

// A boolean compared to true/false can be simplified to Op0/true/false in
// 14 out of the 20 (10 predicates * 2 constants) possible combinations.
// Cases not handled by InstSimplify are always 'not' of Op0.
if (match(B, m_Zero())) {
  switch (I.getPredicate()) {
    case CmpInst::ICMP_EQ:  // A ==   0 -> !A
    case CmpInst::ICMP_ULE: // A <=u  0 -> !A
    case CmpInst::ICMP_SGE: // A >=s  0 -> !A
      return BinaryOperator::CreateNot(A);
    default:
      llvm_unreachable("ICmp i1 X, C not simplified as expected.")::llvm::llvm_unreachable_internal("ICmp i1 X, C not simplified as expected."
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5254);
  }
} else if (match(B, m_One())) {
  switch (I.getPredicate()) {
    case CmpInst::ICMP_NE:  // A !=  1 -> !A
    case CmpInst::ICMP_ULT: // A <u  1 -> !A
    case CmpInst::ICMP_SGT: // A >s -1 -> !A
      return BinaryOperator::CreateNot(A);
    default:
      llvm_unreachable("ICmp i1 X, C not simplified as expected.")::llvm::llvm_unreachable_internal("ICmp i1 X, C not simplified as expected."
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5263);
  }
}

switch (I.getPredicate()) {
default:
  llvm_unreachable("Invalid icmp instruction!")::llvm::llvm_unreachable_internal("Invalid icmp instruction!"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5269);
case ICmpInst::ICMP_EQ:
  // icmp eq i1 A, B -> ~(A ^ B)
  return BinaryOperator::CreateNot(Builder.CreateXor(A, B));

case ICmpInst::ICMP_NE:
  // icmp ne i1 A, B -> A ^ B
  return BinaryOperator::CreateXor(A, B);

case ICmpInst::ICMP_UGT:
  // icmp ugt -> icmp ult
  std::swap(A, B);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_ULT:
  // icmp ult i1 A, B -> ~A & B
  return BinaryOperator::CreateAnd(Builder.CreateNot(A), B);

case ICmpInst::ICMP_SGT:
  // icmp sgt -> icmp slt
  std::swap(A, B);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SLT:
  // icmp slt i1 A, B -> A & ~B
  return BinaryOperator::CreateAnd(Builder.CreateNot(B), A);

case ICmpInst::ICMP_UGE:
  // icmp uge -> icmp ule
  std::swap(A, B);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_ULE:
  // icmp ule i1 A, B -> ~A | B
  return BinaryOperator::CreateOr(Builder.CreateNot(A), B);

case ICmpInst::ICMP_SGE:
  // icmp sge -> icmp sle
  std::swap(A, B);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SLE:
  // icmp sle i1 A, B -> A | ~B
  return BinaryOperator::CreateOr(Builder.CreateNot(B), A);
}
5310}

5312// Transform pattern like:
5313//   (1 << Y) u<= X  or  ~(-1 << Y) u<  X  or  ((1 << Y)+(-1)) u<  X
5314//   (1 << Y) u>  X  or  ~(-1 << Y) u>= X  or  ((1 << Y)+(-1)) u>= X
5315// Into:
5316//   (X l>> Y) != 0
5317//   (X l>> Y) == 0
5318static Instruction *foldICmpWithHighBitMask(ICmpInst &Cmp,
                                          InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate Pred, NewPred;
Value *X, *Y;
if (match(&Cmp,
12
←
Calling 'match<llvm::ICmpInst, llvm::PatternMatch::CmpClass_match<llvm::PatternMatch::OneUse_match<llvm::PatternMatch::BinaryOp_match<llvm::PatternMatch::cst_pred_ty<llvm::PatternMatch::is_one>, llvm::PatternMatch::bind_ty<llvm::Value>, 25, false> >, llvm::PatternMatch::bind_ty<llvm::Value>, llvm::ICmpInst, llvm::CmpInst::Predicate, true>>'→
29
←
Returning from 'match<llvm::ICmpInst, llvm::PatternMatch::CmpClass_match<llvm::PatternMatch::OneUse_match<llvm::PatternMatch::BinaryOp_match<llvm::PatternMatch::cst_pred_ty<llvm::PatternMatch::is_one>, llvm::PatternMatch::bind_ty<llvm::Value>, 25, false> >, llvm::PatternMatch::bind_ty<llvm::Value>, llvm::ICmpInst, llvm::CmpInst::Predicate, true>>'→
30
←
Taking true branch→
          m_c_ICmp(Pred, m_OneUse(m_Shl(m_One(), m_Value(Y))), m_Value(X)))) {
1
Calling 'm_Value'→
5
←
Returning from 'm_Value'→
6
←
Calling 'm_c_ICmp<llvm::PatternMatch::OneUse_match<llvm::PatternMatch::BinaryOp_match<llvm::PatternMatch::cst_pred_ty<llvm::PatternMatch::is_one>, llvm::PatternMatch::bind_ty<llvm::Value>, 25, false> >, llvm::PatternMatch::bind_ty<llvm::Value>>'→
11
←
Returning from 'm_c_ICmp<llvm::PatternMatch::OneUse_match<llvm::PatternMatch::BinaryOp_match<llvm::PatternMatch::cst_pred_ty<llvm::PatternMatch::is_one>, llvm::PatternMatch::bind_ty<llvm::Value>, 25, false> >, llvm::PatternMatch::bind_ty<llvm::Value>>'→
  // We want X to be the icmp's second operand, so swap predicate if it isn't.
  if (Cmp.getOperand(0) == X)
31
←
Assuming pointer value is null→
32
←
Taking true branch→
    Pred = Cmp.getSwappedPredicate();

  switch (Pred) {
33
←
Control jumps to 'case ICMP_UGT:'  at line 5332→
  case ICmpInst::ICMP_ULE:
    NewPred = ICmpInst::ICMP_NE;
    break;
  case ICmpInst::ICMP_UGT:
    NewPred = ICmpInst::ICMP_EQ;
    break;
34
←
 Execution continues on line 5364→
  default:
    return nullptr;
  }
} else if (match(&Cmp, m_c_ICmp(Pred,
                                m_OneUse(m_CombineOr(
                                    m_Not(m_Shl(m_AllOnes(), m_Value(Y))),
                                    m_Add(m_Shl(m_One(), m_Value(Y)),
                                          m_AllOnes()))),
                                m_Value(X)))) {
  // The variant with 'add' is not canonical, (the variant with 'not' is)
  // we only get it because it has extra uses, and can't be canonicalized,

  // We want X to be the icmp's second operand, so swap predicate if it isn't.
  if (Cmp.getOperand(0) == X)
    Pred = Cmp.getSwappedPredicate();

  switch (Pred) {
  case ICmpInst::ICMP_ULT:
    NewPred = ICmpInst::ICMP_NE;
    break;
  case ICmpInst::ICMP_UGE:
    NewPred = ICmpInst::ICMP_EQ;
    break;
  default:
    return nullptr;
  }
} else
  return nullptr;

Value *NewX = Builder.CreateLShr(X, Y, X->getName() + ".highbits");
35
←
Called C++ object pointer is null
Constant *Zero = Constant::getNullValue(NewX->getType());
return CmpInst::Create(Instruction::ICmp, NewPred, NewX, Zero);
5367}

5369static Instruction *foldVectorCmp(CmpInst &Cmp,
                                InstCombiner::BuilderTy &Builder) {
// If both arguments of the cmp are shuffles that use the same mask and
// shuffle within a single vector, move the shuffle after the cmp.
Value *LHS = Cmp.getOperand(0), *RHS = Cmp.getOperand(1);
Value *V1, *V2;
Constant *M;
if (match(LHS, m_ShuffleVector(m_Value(V1), m_Undef(), m_Constant(M))) &&
    match(RHS, m_ShuffleVector(m_Value(V2), m_Undef(), m_Specific(M))) &&
    V1->getType() == V2->getType() &&
    (LHS->hasOneUse() || RHS->hasOneUse())) {
  // cmp (shuffle V1, M), (shuffle V2, M) --> shuffle (cmp V1, V2), M
  CmpInst::Predicate P = Cmp.getPredicate();
  Value *NewCmp = isa<ICmpInst>(Cmp) ? Builder.CreateICmp(P, V1, V2)
                                     : Builder.CreateFCmp(P, V1, V2);
  return new ShuffleVectorInst(NewCmp, UndefValue::get(NewCmp->getType()), M);
}
return nullptr;
5387}

5389// extract(uadd.with.overflow(A, B), 0) ult A
5390//  -> extract(uadd.with.overflow(A, B), 1)
5391static Instruction *foldICmpOfUAddOv(ICmpInst &I) {
CmpInst::Predicate Pred = I.getPredicate();
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);

Value *UAddOv;
Value *A, *B;
auto UAddOvResultPat = m_ExtractValue<0>(
    m_Intrinsic<Intrinsic::uadd_with_overflow>(m_Value(A), m_Value(B)));
if (match(Op0, UAddOvResultPat) &&
    ((Pred == ICmpInst::ICMP_ULT && (Op1 == A || Op1 == B)) ||
     (Pred == ICmpInst::ICMP_EQ && match(Op1, m_ZeroInt()) &&
      (match(A, m_One()) || match(B, m_One()))) ||
     (Pred == ICmpInst::ICMP_NE && match(Op1, m_AllOnes()) &&
      (match(A, m_AllOnes()) || match(B, m_AllOnes())))))
  // extract(uadd.with.overflow(A, B), 0) < A
  // extract(uadd.with.overflow(A, 1), 0) == 0
  // extract(uadd.with.overflow(A, -1), 0) != -1
  UAddOv = cast<ExtractValueInst>(Op0)->getAggregateOperand();
else if (match(Op1, UAddOvResultPat) &&
         Pred == ICmpInst::ICMP_UGT && (Op0 == A || Op0 == B))
  // A > extract(uadd.with.overflow(A, B), 0)
  UAddOv = cast<ExtractValueInst>(Op1)->getAggregateOperand();
else
  return nullptr;

return ExtractValueInst::Create(UAddOv, 1);
5417}

5419Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
bool Changed = false;
const SimplifyQuery Q = SQ.getWithInstruction(&I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
unsigned Op0Cplxity = getComplexity(Op0);
unsigned Op1Cplxity = getComplexity(Op1);

/// Orders the operands of the compare so that they are listed from most
/// complex to least complex.  This puts constants before unary operators,
/// before binary operators.
if (Op0Cplxity < Op1Cplxity ||
    (Op0Cplxity == Op1Cplxity && swapMayExposeCSEOpportunities(Op0, Op1))) {
  I.swapOperands();
  std::swap(Op0, Op1);
  Changed = true;
}

if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, Q))
  return replaceInstUsesWith(I, V);

// Comparing -val or val with non-zero is the same as just comparing val
// ie, abs(val) != 0 -> val != 0
if (I.getPredicate() == ICmpInst::ICMP_NE && match(Op1, m_Zero())) {
  Value *Cond, *SelectTrue, *SelectFalse;
  if (match(Op0, m_Select(m_Value(Cond), m_Value(SelectTrue),
                          m_Value(SelectFalse)))) {
    if (Value *V = dyn_castNegVal(SelectTrue)) {
      if (V == SelectFalse)
        return CmpInst::Create(Instruction::ICmp, I.getPredicate(), V, Op1);
    }
    else if (Value *V = dyn_castNegVal(SelectFalse)) {
      if (V == SelectTrue)
        return CmpInst::Create(Instruction::ICmp, I.getPredicate(), V, Op1);
    }
  }
}

if (Op0->getType()->isIntOrIntVectorTy(1))
  if (Instruction *Res = canonicalizeICmpBool(I, Builder))
    return Res;

if (ICmpInst *NewICmp = canonicalizeCmpWithConstant(I))
  return NewICmp;

if (Instruction *Res = foldICmpWithConstant(I))
  return Res;

if (Instruction *Res = foldICmpWithDominatingICmp(I))
  return Res;

if (Instruction *Res = foldICmpBinOp(I, Q))
  return Res;

if (Instruction *Res = foldICmpUsingKnownBits(I))
  return Res;

// Test if the ICmpInst 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.
//
// Do the same for the other patterns recognized by matchSelectPattern.
if (I.hasOneUse())
  if (SelectInst *SI = dyn_cast<SelectInst>(I.user_back())) {
    Value *A, *B;
    SelectPatternResult SPR = matchSelectPattern(SI, A, B);
    if (SPR.Flavor != SPF_UNKNOWN)
      return nullptr;
  }

// Do this after checking for min/max to prevent infinite looping.
if (Instruction *Res = foldICmpWithZero(I))
  return Res;

// FIXME: We only do this after checking for min/max to prevent infinite
// looping caused by a reverse canonicalization of these patterns for min/max.
// FIXME: The organization of folds is a mess. These would naturally go into
// canonicalizeCmpWithConstant(), but we can't move all of the above folds
// down here after the min/max restriction.
ICmpInst::Predicate Pred = I.getPredicate();
const APInt *C;
if (match(Op1, m_APInt(C))) {
  // For i32: x >u 2147483647 -> x <s 0  -> true if sign bit set
  if (Pred == ICmpInst::ICMP_UGT && C->isMaxSignedValue()) {
    Constant *Zero = Constant::getNullValue(Op0->getType());
    return new ICmpInst(ICmpInst::ICMP_SLT, Op0, Zero);
  }

  // For i32: x <u 2147483648 -> x >s -1  -> true if sign bit clear
  if (Pred == ICmpInst::ICMP_ULT && C->isMinSignedValue()) {
    Constant *AllOnes = Constant::getAllOnesValue(Op0->getType());
    return new ICmpInst(ICmpInst::ICMP_SGT, Op0, AllOnes);
  }
}

if (Instruction *Res = foldICmpInstWithConstant(I))
  return Res;

// Try to match comparison as a sign bit test. Intentionally do this after
// foldICmpInstWithConstant() to potentially let other folds to happen first.
if (Instruction *New = foldSignBitTest(I))
  return New;

if (Instruction *Res = foldICmpInstWithConstantNotInt(I))
  return Res;

// If we can optimize a 'icmp GEP, P' or 'icmp P, GEP', do so now.
if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op0))
  if (Instruction *NI = foldGEPICmp(GEP, Op1, I.getPredicate(), I))
    return NI;
if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1))
  if (Instruction *NI = foldGEPICmp(GEP, Op0,
                         ICmpInst::getSwappedPredicate(I.getPredicate()), I))
    return NI;

// Try to optimize equality comparisons against alloca-based pointers.
if (Op0->getType()->isPointerTy() && I.isEquality()) {
  assert(Op1->getType()->isPointerTy() && "Comparing pointer with non-pointer?")((Op1->getType()->isPointerTy() && "Comparing pointer with non-pointer?"
) ? static_cast<void> (0) : __assert_fail ("Op1->getType()->isPointerTy() && \"Comparing pointer with non-pointer?\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5539, __PRETTY_FUNCTION__));
  if (auto *Alloca = dyn_cast<AllocaInst>(GetUnderlyingObject(Op0, DL)))
    if (Instruction *New = foldAllocaCmp(I, Alloca, Op1))
      return New;
  if (auto *Alloca = dyn_cast<AllocaInst>(GetUnderlyingObject(Op1, DL)))
    if (Instruction *New = foldAllocaCmp(I, Alloca, Op0))
      return New;
}

if (Instruction *Res = foldICmpBitCast(I, Builder))
  return Res;

if (Instruction *R = foldICmpWithCastOp(I))
  return R;

if (Instruction *Res = foldICmpWithMinMax(I))
  return Res;

{
  Value *A, *B;
  // Transform (A & ~B) == 0 --> (A & B) != 0
  // and       (A & ~B) != 0 --> (A & B) == 0
  // if A is a power of 2.
  if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
      match(Op1, m_Zero()) &&
      isKnownToBeAPowerOfTwo(A, false, 0, &I) && I.isEquality())
    return new ICmpInst(I.getInversePredicate(), Builder.CreateAnd(A, B),
                        Op1);

  // ~X < ~Y --> Y < X
  // ~X < C -->  X > ~C
  if (match(Op0, m_Not(m_Value(A)))) {
    if (match(Op1, m_Not(m_Value(B))))
      return new ICmpInst(I.getPredicate(), B, A);

    const APInt *C;
    if (match(Op1, m_APInt(C)))
      return new ICmpInst(I.getSwappedPredicate(), A,
                          ConstantInt::get(Op1->getType(), ~(*C)));
  }

  Instruction *AddI = nullptr;
  if (match(&I, m_UAddWithOverflow(m_Value(A), m_Value(B),
                                   m_Instruction(AddI))) &&
      isa<IntegerType>(A->getType())) {
    Value *Result;
    Constant *Overflow;
    if (OptimizeOverflowCheck(Instruction::Add, /*Signed*/false, A, B,
                              *AddI, Result, Overflow)) {
      replaceInstUsesWith(*AddI, Result);
      return replaceInstUsesWith(I, Overflow);
    }
  }

  // (zext a) * (zext b)  --> llvm.umul.with.overflow.
  if (match(Op0, m_Mul(m_ZExt(m_Value(A)), m_ZExt(m_Value(B))))) {
    if (Instruction *R = processUMulZExtIdiom(I, Op0, Op1, *this))
      return R;
  }
  if (match(Op1, m_Mul(m_ZExt(m_Value(A)), m_ZExt(m_Value(B))))) {
    if (Instruction *R = processUMulZExtIdiom(I, Op1, Op0, *this))
      return R;
  }
}

if (Instruction *Res = foldICmpEquality(I))
  return Res;

if (Instruction *Res = foldICmpOfUAddOv(I))
  return Res;

// The 'cmpxchg' instruction returns an aggregate containing the old value and
// an i1 which indicates whether or not we successfully did the swap.
//
// Replace comparisons between the old value and the expected value with the
// indicator that 'cmpxchg' returns.
//
// N.B.  This transform is only valid when the 'cmpxchg' is not permitted to
// spuriously fail.  In those cases, the old value may equal the expected
// value but it is possible for the swap to not occur.
if (I.getPredicate() == ICmpInst::ICMP_EQ)
  if (auto *EVI = dyn_cast<ExtractValueInst>(Op0))
    if (auto *ACXI = dyn_cast<AtomicCmpXchgInst>(EVI->getAggregateOperand()))
      if (EVI->getIndices()[0] == 0 && ACXI->getCompareOperand() == Op1 &&
          !ACXI->isWeak())
        return ExtractValueInst::Create(ACXI, 1);

{
  Value *X;
  const APInt *C;
  // icmp X+Cst, X
  if (match(Op0, m_Add(m_Value(X), m_APInt(C))) && Op1 == X)
    return foldICmpAddOpConst(X, *C, I.getPredicate());

  // icmp X, X+Cst
  if (match(Op1, m_Add(m_Value(X), m_APInt(C))) && Op0 == X)
    return foldICmpAddOpConst(X, *C, I.getSwappedPredicate());
}

if (Instruction *Res = foldICmpWithHighBitMask(I, Builder))
  return Res;

if (I.getType()->isVectorTy())
  if (Instruction *Res = foldVectorCmp(I, Builder))
    return Res;

return Changed ? &I : nullptr;
5646}

5648/// Fold fcmp ([us]itofp x, cst) if possible.
5649Instruction *InstCombiner::foldFCmpIntToFPConst(FCmpInst &I, Instruction *LHSI,
                                              Constant *RHSC) {
if (!isa<ConstantFP>(RHSC)) return nullptr;
const APFloat &RHS = cast<ConstantFP>(RHSC)->getValueAPF();

// Get the width of the mantissa.  We don't want to hack on conversions that
// might lose information from the integer, e.g. "i64 -> float"
int MantissaWidth = LHSI->getType()->getFPMantissaWidth();
if (MantissaWidth == -1) return nullptr;  // Unknown.

IntegerType *IntTy = cast<IntegerType>(LHSI->getOperand(0)->getType());

bool LHSUnsigned = isa<UIToFPInst>(LHSI);

if (I.isEquality()) {
  FCmpInst::Predicate P = I.getPredicate();
  bool IsExact = false;
  APSInt RHSCvt(IntTy->getBitWidth(), LHSUnsigned);
  RHS.convertToInteger(RHSCvt, APFloat::rmNearestTiesToEven, &IsExact);

  // If the floating point constant isn't an integer value, we know if we will
  // ever compare equal / not equal to it.
  if (!IsExact) {
    // TODO: Can never be -0.0 and other non-representable values
    APFloat RHSRoundInt(RHS);
    RHSRoundInt.roundToIntegral(APFloat::rmNearestTiesToEven);
    if (RHS.compare(RHSRoundInt) != APFloat::cmpEqual) {
      if (P == FCmpInst::FCMP_OEQ || P == FCmpInst::FCMP_UEQ)
        return replaceInstUsesWith(I, Builder.getFalse());

      assert(P == FCmpInst::FCMP_ONE || P == FCmpInst::FCMP_UNE)((P == FCmpInst::FCMP_ONE || P == FCmpInst::FCMP_UNE) ? static_cast
<void> (0) : __assert_fail ("P == FCmpInst::FCMP_ONE || P == FCmpInst::FCMP_UNE"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5679, __PRETTY_FUNCTION__));
      return replaceInstUsesWith(I, Builder.getTrue());
    }
  }

  // TODO: If the constant is exactly representable, is it always OK to do
  // equality compares as integer?
}

// Check to see that the input is converted from an integer type that is small
// enough that preserves all bits.  TODO: check here for "known" sign bits.
// This would allow us to handle (fptosi (x >>s 62) to float) if x is i64 f.e.
unsigned InputSize = IntTy->getScalarSizeInBits();

// Following test does NOT adjust InputSize downwards for signed inputs,
// because the most negative value still requires all the mantissa bits
// to distinguish it from one less than that value.
if ((int)InputSize > MantissaWidth) {
  // Conversion would lose accuracy. Check if loss can impact comparison.
  int Exp = ilogb(RHS);
  if (Exp == APFloat::IEK_Inf) {
    int MaxExponent = ilogb(APFloat::getLargest(RHS.getSemantics()));
    if (MaxExponent < (int)InputSize - !LHSUnsigned)
      // Conversion could create infinity.
      return nullptr;
  } else {
    // Note that if RHS is zero or NaN, then Exp is negative
    // and first condition is trivially false.
    if (MantissaWidth <= Exp && Exp <= (int)InputSize - !LHSUnsigned)
      // Conversion could affect comparison.
      return nullptr;
  }
}

// Otherwise, we can potentially simplify the comparison.  We know that it
// will always come through as an integer value and we know the constant is
// not a NAN (it would have been previously simplified).
assert(!RHS.isNaN() && "NaN comparison not already folded!")((!RHS.isNaN() && "NaN comparison not already folded!"
) ? static_cast<void> (0) : __assert_fail ("!RHS.isNaN() && \"NaN comparison not already folded!\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5716, __PRETTY_FUNCTION__));

ICmpInst::Predicate Pred;
switch (I.getPredicate()) {
default: llvm_unreachable("Unexpected predicate!")::llvm::llvm_unreachable_internal("Unexpected predicate!", "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5720);
case FCmpInst::FCMP_UEQ:
case FCmpInst::FCMP_OEQ:
  Pred = ICmpInst::ICMP_EQ;
  break;
case FCmpInst::FCMP_UGT:
case FCmpInst::FCMP_OGT:
  Pred = LHSUnsigned ? ICmpInst::ICMP_UGT : ICmpInst::ICMP_SGT;
  break;
case FCmpInst::FCMP_UGE:
case FCmpInst::FCMP_OGE:
  Pred = LHSUnsigned ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_SGE;
  break;
case FCmpInst::FCMP_ULT:
case FCmpInst::FCMP_OLT:
  Pred = LHSUnsigned ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_SLT;
  break;
case FCmpInst::FCMP_ULE:
case FCmpInst::FCMP_OLE:
  Pred = LHSUnsigned ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_SLE;
  break;
case FCmpInst::FCMP_UNE:
case FCmpInst::FCMP_ONE:
  Pred = ICmpInst::ICMP_NE;
  break;
case FCmpInst::FCMP_ORD:
  return replaceInstUsesWith(I, Builder.getTrue());
case FCmpInst::FCMP_UNO:
  return replaceInstUsesWith(I, Builder.getFalse());
}

// Now we know that the APFloat is a normal number, zero or inf.

// See if the FP constant is too large for the integer.  For example,
// comparing an i8 to 300.0.
unsigned IntWidth = IntTy->getScalarSizeInBits();

if (!LHSUnsigned) {
  // If the RHS value is > SignedMax, fold the comparison.  This handles +INF
  // and large values.
  APFloat SMax(RHS.getSemantics());
  SMax.convertFromAPInt(APInt::getSignedMaxValue(IntWidth), true,
                        APFloat::rmNearestTiesToEven);
  if (SMax.compare(RHS) == APFloat::cmpLessThan) {  // smax < 13123.0
    if (Pred == ICmpInst::ICMP_NE  || Pred == ICmpInst::ICMP_SLT ||
        Pred == ICmpInst::ICMP_SLE)
      return replaceInstUsesWith(I, Builder.getTrue());
    return replaceInstUsesWith(I, Builder.getFalse());
  }
} else {
  // If the RHS value is > UnsignedMax, fold the comparison. This handles
  // +INF and large values.
  APFloat UMax(RHS.getSemantics());
  UMax.convertFromAPInt(APInt::getMaxValue(IntWidth), false,
                        APFloat::rmNearestTiesToEven);
  if (UMax.compare(RHS) == APFloat::cmpLessThan) {  // umax < 13123.0
    if (Pred == ICmpInst::ICMP_NE  || Pred == ICmpInst::ICMP_ULT ||
        Pred == ICmpInst::ICMP_ULE)
      return replaceInstUsesWith(I, Builder.getTrue());
    return replaceInstUsesWith(I, Builder.getFalse());
  }
}

if (!LHSUnsigned) {
  // See if the RHS value is < SignedMin.
  APFloat SMin(RHS.getSemantics());
  SMin.convertFromAPInt(APInt::getSignedMinValue(IntWidth), true,
                        APFloat::rmNearestTiesToEven);
  if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // smin > 12312.0
    if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT ||
        Pred == ICmpInst::ICMP_SGE)
      return replaceInstUsesWith(I, Builder.getTrue());
    return replaceInstUsesWith(I, Builder.getFalse());
  }
} else {
  // See if the RHS value is < UnsignedMin.
  APFloat SMin(RHS.getSemantics());
  SMin.convertFromAPInt(APInt::getMinValue(IntWidth), true,
                        APFloat::rmNearestTiesToEven);
  if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // umin > 12312.0
    if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_UGT ||
        Pred == ICmpInst::ICMP_UGE)
      return replaceInstUsesWith(I, Builder.getTrue());
    return replaceInstUsesWith(I, Builder.getFalse());
  }
}

// Okay, now we know that the FP constant fits in the range [SMIN, SMAX] or
// [0, UMAX], but it may still be fractional.  See if it is fractional by
// casting the FP value to the integer value and back, checking for equality.
// Don't do this for zero, because -0.0 is not fractional.
Constant *RHSInt = LHSUnsigned
  ? ConstantExpr::getFPToUI(RHSC, IntTy)
  : ConstantExpr::getFPToSI(RHSC, IntTy);
if (!RHS.isZero()) {
  bool Equal = LHSUnsigned
    ? ConstantExpr::getUIToFP(RHSInt, RHSC->getType()) == RHSC
    : ConstantExpr::getSIToFP(RHSInt, RHSC->getType()) == RHSC;
  if (!Equal) {
    // If we had a comparison against a fractional value, we have to adjust
    // the compare predicate and sometimes the value.  RHSC is rounded towards
    // zero at this point.
    switch (Pred) {
    default: llvm_unreachable("Unexpected integer comparison!")::llvm::llvm_unreachable_internal("Unexpected integer comparison!"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5823);
    case ICmpInst::ICMP_NE:  // (float)int != 4.4   --> true
      return replaceInstUsesWith(I, Builder.getTrue());
    case ICmpInst::ICMP_EQ:  // (float)int == 4.4   --> false
      return replaceInstUsesWith(I, Builder.getFalse());
    case ICmpInst::ICMP_ULE:
      // (float)int <= 4.4   --> int <= 4
      // (float)int <= -4.4  --> false
      if (RHS.isNegative())
        return replaceInstUsesWith(I, Builder.getFalse());
      break;
    case ICmpInst::ICMP_SLE:
      // (float)int <= 4.4   --> int <= 4
      // (float)int <= -4.4  --> int < -4
      if (RHS.isNegative())
        Pred = ICmpInst::ICMP_SLT;
      break;
    case ICmpInst::ICMP_ULT:
      // (float)int < -4.4   --> false
      // (float)int < 4.4    --> int <= 4
      if (RHS.isNegative())
        return replaceInstUsesWith(I, Builder.getFalse());
      Pred = ICmpInst::ICMP_ULE;
      break;
    case ICmpInst::ICMP_SLT:
      // (float)int < -4.4   --> int < -4
      // (float)int < 4.4    --> int <= 4
      if (!RHS.isNegative())
        Pred = ICmpInst::ICMP_SLE;
      break;
    case ICmpInst::ICMP_UGT:
      // (float)int > 4.4    --> int > 4
      // (float)int > -4.4   --> true
      if (RHS.isNegative())
        return replaceInstUsesWith(I, Builder.getTrue());
      break;
    case ICmpInst::ICMP_SGT:
      // (float)int > 4.4    --> int > 4
      // (float)int > -4.4   --> int >= -4
      if (RHS.isNegative())
        Pred = ICmpInst::ICMP_SGE;
      break;
    case ICmpInst::ICMP_UGE:
      // (float)int >= -4.4   --> true
      // (float)int >= 4.4    --> int > 4
      if (RHS.isNegative())
        return replaceInstUsesWith(I, Builder.getTrue());
      Pred = ICmpInst::ICMP_UGT;
      break;
    case ICmpInst::ICMP_SGE:
      // (float)int >= -4.4   --> int >= -4
      // (float)int >= 4.4    --> int > 4
      if (!RHS.isNegative())
        Pred = ICmpInst::ICMP_SGT;
      break;
    }
  }
}

// Lower this FP comparison into an appropriate integer version of the
// comparison.
return new ICmpInst(Pred, LHSI->getOperand(0), RHSInt);
5885}

5887/// Fold (C / X) < 0.0 --> X < 0.0 if possible. Swap predicate if necessary.
5888static Instruction *foldFCmpReciprocalAndZero(FCmpInst &I, Instruction *LHSI,
                                            Constant *RHSC) {
// When C is not 0.0 and infinities are not allowed:
// (C / X) < 0.0 is a sign-bit test of X
// (C / X) < 0.0 --> X < 0.0 (if C is positive)
// (C / X) < 0.0 --> X > 0.0 (if C is negative, swap the predicate)
//
// Proof:
// Multiply (C / X) < 0.0 by X * X / C.
// - X is non zero, if it is the flag 'ninf' is violated.
// - C defines the sign of X * X * C. Thus it also defines whether to swap
//   the predicate. C is also non zero by definition.
//
// Thus X * X / C is non zero and the transformation is valid. [qed]

FCmpInst::Predicate Pred = I.getPredicate();

// Check that predicates are valid.
if ((Pred != FCmpInst::FCMP_OGT) && (Pred != FCmpInst::FCMP_OLT) &&
    (Pred != FCmpInst::FCMP_OGE) && (Pred != FCmpInst::FCMP_OLE))
  return nullptr;

// Check that RHS operand is zero.
if (!match(RHSC, m_AnyZeroFP()))
  return nullptr;

// Check fastmath flags ('ninf').
if (!LHSI->hasNoInfs() || !I.hasNoInfs())
  return nullptr;

// Check the properties of the dividend. It must not be zero to avoid a
// division by zero (see Proof).
const APFloat *C;
if (!match(LHSI->getOperand(0), m_APFloat(C)))
  return nullptr;

if (C->isZero())
  return nullptr;

// Get swapped predicate if necessary.
if (C->isNegative())
  Pred = I.getSwappedPredicate();

return new FCmpInst(Pred, LHSI->getOperand(1), RHSC, "", &I);
5932}

5934/// Optimize fabs(X) compared with zero.
5935static Instruction *foldFabsWithFcmpZero(FCmpInst &I) {
Value *X;
if (!match(I.getOperand(0), m_Intrinsic<Intrinsic::fabs>(m_Value(X))) ||
    !match(I.getOperand(1), m_PosZeroFP()))
  return nullptr;

auto replacePredAndOp0 = [](FCmpInst *I, FCmpInst::Predicate P, Value *X) {
  I->setPredicate(P);
  I->setOperand(0, X);
  return I;
};

switch (I.getPredicate()) {
case FCmpInst::FCMP_UGE:
case FCmpInst::FCMP_OLT:
  // fabs(X) >= 0.0 --> true
  // fabs(X) <  0.0 --> false
  llvm_unreachable("fcmp should have simplified")::llvm::llvm_unreachable_internal("fcmp should have simplified"
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5952);

case FCmpInst::FCMP_OGT:
  // fabs(X) > 0.0 --> X != 0.0
  return replacePredAndOp0(&I, FCmpInst::FCMP_ONE, X);

case FCmpInst::FCMP_UGT:
  // fabs(X) u> 0.0 --> X u!= 0.0
  return replacePredAndOp0(&I, FCmpInst::FCMP_UNE, X);

case FCmpInst::FCMP_OLE:
  // fabs(X) <= 0.0 --> X == 0.0
  return replacePredAndOp0(&I, FCmpInst::FCMP_OEQ, X);

case FCmpInst::FCMP_ULE:
  // fabs(X) u<= 0.0 --> X u== 0.0
  return replacePredAndOp0(&I, FCmpInst::FCMP_UEQ, X);

case FCmpInst::FCMP_OGE:
  // fabs(X) >= 0.0 --> !isnan(X)
  assert(!I.hasNoNaNs() && "fcmp should have simplified")((!I.hasNoNaNs() && "fcmp should have simplified") ? static_cast
<void> (0) : __assert_fail ("!I.hasNoNaNs() && \"fcmp should have simplified\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5972, __PRETTY_FUNCTION__));
  return replacePredAndOp0(&I, FCmpInst::FCMP_ORD, X);

case FCmpInst::FCMP_ULT:
  // fabs(X) u< 0.0 --> isnan(X)
  assert(!I.hasNoNaNs() && "fcmp should have simplified")((!I.hasNoNaNs() && "fcmp should have simplified") ? static_cast
<void> (0) : __assert_fail ("!I.hasNoNaNs() && \"fcmp should have simplified\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5977, __PRETTY_FUNCTION__));
  return replacePredAndOp0(&I, FCmpInst::FCMP_UNO, X);

case FCmpInst::FCMP_OEQ:
case FCmpInst::FCMP_UEQ:
case FCmpInst::FCMP_ONE:
case FCmpInst::FCMP_UNE:
case FCmpInst::FCMP_ORD:
case FCmpInst::FCMP_UNO:
  // Look through the fabs() because it doesn't change anything but the sign.
  // fabs(X) == 0.0 --> X == 0.0,
  // fabs(X) != 0.0 --> X != 0.0
  // isnan(fabs(X)) --> isnan(X)
  // !isnan(fabs(X) --> !isnan(X)
  return replacePredAndOp0(&I, I.getPredicate(), X);

default:
  return nullptr;
}
5996}

5998Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
bool Changed = false;

/// Orders the operands of the compare so that they are listed from most
/// complex to least complex.  This puts constants before unary operators,
/// before binary operators.
if (getComplexity(I.getOperand(0)) < getComplexity(I.getOperand(1))) {
  I.swapOperands();
  Changed = true;
}

const CmpInst::Predicate Pred = I.getPredicate();
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
if (Value *V = SimplifyFCmpInst(Pred, Op0, Op1, I.getFastMathFlags(),
                                SQ.getWithInstruction(&I)))
  return replaceInstUsesWith(I, V);

// Simplify 'fcmp pred X, X'
Type *OpType = Op0->getType();
assert(OpType == Op1->getType() && "fcmp with different-typed operands?")((OpType == Op1->getType() && "fcmp with different-typed operands?"
) ? static_cast<void> (0) : __assert_fail ("OpType == Op1->getType() && \"fcmp with different-typed operands?\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 6017, __PRETTY_FUNCTION__));
if (Op0 == Op1) {
  switch (Pred) {
    default: break;
  case FCmpInst::FCMP_UNO:    // True if unordered: isnan(X) | isnan(Y)
  case FCmpInst::FCMP_ULT:    // True if unordered or less than
  case FCmpInst::FCMP_UGT:    // True if unordered or greater than
  case FCmpInst::FCMP_UNE:    // True if unordered or not equal
    // Canonicalize these to be 'fcmp uno %X, 0.0'.
    I.setPredicate(FCmpInst::FCMP_UNO);
    I.setOperand(1, Constant::getNullValue(OpType));
    return &I;

  case FCmpInst::FCMP_ORD:    // True if ordered (no nans)
  case FCmpInst::FCMP_OEQ:    // True if ordered and equal
  case FCmpInst::FCMP_OGE:    // True if ordered and greater than or equal
  case FCmpInst::FCMP_OLE:    // True if ordered and less than or equal
    // Canonicalize these to be 'fcmp ord %X, 0.0'.
    I.setPredicate(FCmpInst::FCMP_ORD);
    I.setOperand(1, Constant::getNullValue(OpType));
    return &I;
  }
}

// If we're just checking for a NaN (ORD/UNO) and have a non-NaN operand,
// then canonicalize the operand to 0.0.
if (Pred == CmpInst::FCMP_ORD || Pred == CmpInst::FCMP_UNO) {
  if (!match(Op0, m_PosZeroFP()) && isKnownNeverNaN(Op0, &TLI)) {
    I.setOperand(0, ConstantFP::getNullValue(OpType));
    return &I;
  }
  if (!match(Op1, m_PosZeroFP()) && isKnownNeverNaN(Op1, &TLI)) {
    I.setOperand(1, ConstantFP::getNullValue(OpType));
    return &I;
  }
}

// fcmp pred (fneg X), (fneg Y) -> fcmp swap(pred) X, Y
Value *X, *Y;
if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y))))
  return new FCmpInst(I.getSwappedPredicate(), X, Y, "", &I);

// Test if the FCmpInst 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 (I.hasOneUse())
  if (SelectInst *SI = dyn_cast<SelectInst>(I.user_back())) {
    Value *A, *B;
    SelectPatternResult SPR = matchSelectPattern(SI, A, B);
    if (SPR.Flavor != SPF_UNKNOWN)
      return nullptr;
  }

// The sign of 0.0 is ignored by fcmp, so canonicalize to +0.0:
// fcmp Pred X, -0.0 --> fcmp Pred X, 0.0
if (match(Op1, m_AnyZeroFP()) && !match(Op1, m_PosZeroFP())) {
  I.setOperand(1, ConstantFP::getNullValue(OpType));
  return &I;
}

// Handle fcmp with instruction LHS and constant RHS.
Instruction *LHSI;
Constant *RHSC;
if (match(Op0, m_Instruction(LHSI)) && match(Op1, m_Constant(RHSC))) {
  switch (LHSI->getOpcode()) {
  case Instruction::PHI:
    // Only fold fcmp into the PHI if the phi and fcmp are in the same
    // block.  If in the same block, we're encouraging jump threading.  If
    // not, we are just pessimizing the code by making an i1 phi.
    if (LHSI->getParent() == I.getParent())
      if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
        return NV;
    break;
  case Instruction::SIToFP:
  case Instruction::UIToFP:
    if (Instruction *NV = foldFCmpIntToFPConst(I, LHSI, RHSC))
      return NV;
    break;
  case Instruction::FDiv:
    if (Instruction *NV = foldFCmpReciprocalAndZero(I, LHSI, RHSC))
      return NV;
    break;
  case Instruction::Load:
    if (auto *GEP = dyn_cast<GetElementPtrInst>(LHSI->getOperand(0)))
      if (auto *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
        if (GV->isConstant() && GV->hasDefinitiveInitializer() &&
            !cast<LoadInst>(LHSI)->isVolatile())
          if (Instruction *Res = foldCmpLoadFromIndexedGlobal(GEP, GV, I))
            return Res;
    break;
}
}

if (Instruction *R = foldFabsWithFcmpZero(I))
  return R;

if (match(Op0, m_FNeg(m_Value(X)))) {
  // fcmp pred (fneg X), C --> fcmp swap(pred) X, -C
  Constant *C;
  if (match(Op1, m_Constant(C))) {
    Constant *NegC = ConstantExpr::getFNeg(C);
    return new FCmpInst(I.getSwappedPredicate(), X, NegC, "", &I);
  }
}

if (match(Op0, m_FPExt(m_Value(X)))) {
  // fcmp (fpext X), (fpext Y) -> fcmp X, Y
  if (match(Op1, m_FPExt(m_Value(Y))) && X->getType() == Y->getType())
    return new FCmpInst(Pred, X, Y, "", &I);

  // fcmp (fpext X), C -> fcmp X, (fptrunc C) if fptrunc is lossless
  const APFloat *C;
  if (match(Op1, m_APFloat(C))) {
    const fltSemantics &FPSem =
        X->getType()->getScalarType()->getFltSemantics();
    bool Lossy;
    APFloat TruncC = *C;
    TruncC.convert(FPSem, APFloat::rmNearestTiesToEven, &Lossy);

    // Avoid lossy conversions and denormals.
    // Zero is a special case that's OK to convert.
    APFloat Fabs = TruncC;
    Fabs.clearSign();
    if (!Lossy &&
        ((Fabs.compare(APFloat::getSmallestNormalized(FPSem)) !=
          APFloat::cmpLessThan) || Fabs.isZero())) {
      Constant *NewC = ConstantFP::get(X->getType(), TruncC);
      return new FCmpInst(Pred, X, NewC, "", &I);
    }
  }
}

if (I.getType()->isVectorTy())
  if (Instruction *Res = foldVectorCmp(I, Builder))
    return Res;

return Changed ? &I : nullptr;
6158}

←

/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/include/llvm/IR/PatternMatch.h

1//===- PatternMatch.h - Match on the LLVM IR --------------------*- 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 provides a simple and efficient mechanism for performing general
10// tree-based pattern matches on the LLVM IR. The power of these routines is
11// that it allows you to write concise patterns that are expressive and easy to
12// understand. The other major advantage of this is that it allows you to
13// trivially capture/bind elements in the pattern to variables. For example,
14// you can do something like this:
15//
16//  Value *Exp = ...
17//  Value *X, *Y;  ConstantInt *C1, *C2;      // (X & C1) | (Y & C2)
18//  if (match(Exp, m_Or(m_And(m_Value(X), m_ConstantInt(C1)),
19//                      m_And(m_Value(Y), m_ConstantInt(C2))))) {
20//    ... Pattern is matched and variables are bound ...
21//  }
22//
23// This is primarily useful to things like the instruction combiner, but can
24// also be useful for static analysis tools or code generators.
25//
26//===----------------------------------------------------------------------===//
27 
28#ifndef LLVM_IR_PATTERNMATCH_H
29#define LLVM_IR_PATTERNMATCH_H
30 
31#include "llvm/ADT/APFloat.h"
32#include "llvm/ADT/APInt.h"
33#include "llvm/IR/Constant.h"
34#include "llvm/IR/Constants.h"
35#include "llvm/IR/InstrTypes.h"
36#include "llvm/IR/Instruction.h"
37#include "llvm/IR/Instructions.h"
38#include "llvm/IR/IntrinsicInst.h"
39#include "llvm/IR/Intrinsics.h"
40#include "llvm/IR/Operator.h"
41#include "llvm/IR/Value.h"
42#include "llvm/Support/Casting.h"
43#include <cstdint>
44 
45namespace llvm {
46namespace PatternMatch {
47 
48template <typename Val, typename Pattern> bool match(Val *V, const Pattern &P) {
49  return const_cast<Pattern &>(P).match(V);
13
←
Calling 'CmpClass_match::match'→
27
←
Returning from 'CmpClass_match::match'→
28
←
Returning the value 1, which participates in a condition later→
50}
51 
52template <typename SubPattern_t> struct OneUse_match {
53  SubPattern_t SubPattern;
54 
55  OneUse_match(const SubPattern_t &SP) : SubPattern(SP) {}
56 
57  template <typename OpTy> bool match(OpTy *V) {
58    return V->hasOneUse() && SubPattern.match(V);
17
←
Assuming the condition is true→
18
←
Calling 'BinaryOp_match::match'→
24
←
Returning from 'BinaryOp_match::match'→
59  }
60};
61 
62template <typename T> inline OneUse_match<T> m_OneUse(const T &SubPattern) {
63  return SubPattern;
64}
65 
66template <typename Class> struct class_match {
67  template <typename ITy> bool match(ITy *V) { return isa<Class>(V); }
68};
69 
70/// Match an arbitrary value and ignore it.
71inline class_match<Value> m_Value() { return class_match<Value>(); }
72 
73/// Match an arbitrary binary operation and ignore it.
74inline class_match<BinaryOperator> m_BinOp() {
75  return class_match<BinaryOperator>();
76}
77 
78/// Matches any compare instruction and ignore it.
79inline class_match<CmpInst> m_Cmp() { return class_match<CmpInst>(); }
80 
81/// Match an arbitrary ConstantInt and ignore it.
82inline class_match<ConstantInt> m_ConstantInt() {
83  return class_match<ConstantInt>();
84}
85 
86/// Match an arbitrary undef constant.
87inline class_match<UndefValue> m_Undef() { return class_match<UndefValue>(); }
88 
89/// Match an arbitrary Constant and ignore it.
90inline class_match<Constant> m_Constant() { return class_match<Constant>(); }
91 
92/// Match an arbitrary basic block value and ignore it.
93inline class_match<BasicBlock> m_BasicBlock() {
94  return class_match<BasicBlock>();
95}
96 
97/// Inverting matcher
98template <typename Ty> struct match_unless {
99  Ty M;
100 
101  match_unless(const Ty &Matcher) : M(Matcher) {}
102 
103  template <typename ITy> bool match(ITy *V) { return !M.match(V); }
104};
105 
106/// Match if the inner matcher does *NOT* match.
107template <typename Ty> inline match_unless<Ty> m_Unless(const Ty &M) {
108  return match_unless<Ty>(M);
109}
110 
111/// Matching combinators
112template <typename LTy, typename RTy> struct match_combine_or {
113  LTy L;
114  RTy R;
115 
116  match_combine_or(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
117 
118  template <typename ITy> bool match(ITy *V) {
119    if (L.match(V))
120      return true;
121    if (R.match(V))
122      return true;
123    return false;
124  }
125};
126 
127template <typename LTy, typename RTy> struct match_combine_and {
128  LTy L;
129  RTy R;
130 
131  match_combine_and(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
132 
133  template <typename ITy> bool match(ITy *V) {
134    if (L.match(V))
135      if (R.match(V))
136        return true;
137    return false;
138  }
139};
140 
141/// Combine two pattern matchers matching L || R
142template <typename LTy, typename RTy>
143inline match_combine_or<LTy, RTy> m_CombineOr(const LTy &L, const RTy &R) {
144  return match_combine_or<LTy, RTy>(L, R);
145}
146 
147/// Combine two pattern matchers matching L && R
148template <typename LTy, typename RTy>
149inline match_combine_and<LTy, RTy> m_CombineAnd(const LTy &L, const RTy &R) {
150  return match_combine_and<LTy, RTy>(L, R);
151}
152 
153struct apint_match {
154  const APInt *&Res;
155 
156  apint_match(const APInt *&R) : Res(R) {}
157 
158  template <typename ITy> bool match(ITy *V) {
159    if (auto *CI = dyn_cast<ConstantInt>(V)) {
160      Res = &CI->getValue();
161      return true;
162    }
163    if (V->getType()->isVectorTy())
164      if (const auto *C = dyn_cast<Constant>(V))
165        if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) {
166          Res = &CI->getValue();
167          return true;
168        }
169    return false;
170  }
171};
172// Either constexpr if or renaming ConstantFP::getValueAPF to
173// ConstantFP::getValue is needed to do it via single template
174// function for both apint/apfloat.
175struct apfloat_match {
176  const APFloat *&Res;
177  apfloat_match(const APFloat *&R) : Res(R) {}
178  template <typename ITy> bool match(ITy *V) {
179    if (auto *CI = dyn_cast<ConstantFP>(V)) {
180      Res = &CI->getValueAPF();
181      return true;
182    }
183    if (V->getType()->isVectorTy())
184      if (const auto *C = dyn_cast<Constant>(V))
185        if (auto *CI = dyn_cast_or_null<ConstantFP>(C->getSplatValue())) {
186          Res = &CI->getValueAPF();
187          return true;
188        }
189    return false;
190  }
191};
192 
193/// Match a ConstantInt or splatted ConstantVector, binding the
194/// specified pointer to the contained APInt.
195inline apint_match m_APInt(const APInt *&Res) { return Res; }
196 
197/// Match a ConstantFP or splatted ConstantVector, binding the
198/// specified pointer to the contained APFloat.
199inline apfloat_match m_APFloat(const APFloat *&Res) { return Res; }
200 
201template <int64_t Val> struct constantint_match {
202  template <typename ITy> bool match(ITy *V) {
203    if (const auto *CI = dyn_cast<ConstantInt>(V)) {
204      const APInt &CIV = CI->getValue();
205      if (Val >= 0)
206        return CIV == static_cast<uint64_t>(Val);
207      // If Val is negative, and CI is shorter than it, truncate to the right
208      // number of bits.  If it is larger, then we have to sign extend.  Just
209      // compare their negated values.
210      return -CIV == -Val;
211    }
212    return false;
213  }
214};
215 
216/// Match a ConstantInt with a specific value.
217template <int64_t Val> inline constantint_match<Val> m_ConstantInt() {
218  return constantint_match<Val>();
219}
220 
221/// This helper class is used to match scalar and vector integer constants that
222/// satisfy a specified predicate.
223/// For vector constants, undefined elements are ignored.
224template <typename Predicate> struct cst_pred_ty : public Predicate {
225  template <typename ITy> bool match(ITy *V) {
226    if (const auto *CI = dyn_cast<ConstantInt>(V))
227      return this->isValue(CI->getValue());
228    if (V->getType()->isVectorTy()) {
229      if (const auto *C = dyn_cast<Constant>(V)) {
230        if (const auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
231          return this->isValue(CI->getValue());
232 
233        // Non-splat vector constant: check each element for a match.
234        unsigned NumElts = V->getType()->getVectorNumElements();
235        assert(NumElts != 0 && "Constant vector with no elements?")((NumElts != 0 && "Constant vector with no elements?"
) ? static_cast<void> (0) : __assert_fail ("NumElts != 0 && \"Constant vector with no elements?\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/include/llvm/IR/PatternMatch.h"
, 235, __PRETTY_FUNCTION__));
236        bool HasNonUndefElements = false;
237        for (unsigned i = 0; i != NumElts; ++i) {
238          Constant *Elt = C->getAggregateElement(i);
239          if (!Elt)
240            return false;
241          if (isa<UndefValue>(Elt))
242            continue;
243          auto *CI = dyn_cast<ConstantInt>(Elt);
244          if (!CI || !this->isValue(CI->getValue()))
245            return false;
246          HasNonUndefElements = true;
247        }
248        return HasNonUndefElements;
249      }
250    }
251    return false;
252  }
253};
254 
255/// This helper class is used to match scalar and vector constants that
256/// satisfy a specified predicate, and bind them to an APInt.
257template <typename Predicate> struct api_pred_ty : public Predicate {
258  const APInt *&Res;
259 
260  api_pred_ty(const APInt *&R) : Res(R) {}
261 
262  template <typename ITy> bool match(ITy *V) {
263    if (const auto *CI = dyn_cast<ConstantInt>(V))
264      if (this->isValue(CI->getValue())) {
265        Res = &CI->getValue();
266        return true;
267      }
268    if (V->getType()->isVectorTy())
269      if (const auto *C = dyn_cast<Constant>(V))
270        if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
271          if (this->isValue(CI->getValue())) {
272            Res = &CI->getValue();
273            return true;
274          }
275 
276    return false;
277  }
278};
279 
280/// This helper class is used to match scalar and vector floating-point
281/// constants that satisfy a specified predicate.
282/// For vector constants, undefined elements are ignored.
283template <typename Predicate> struct cstfp_pred_ty : public Predicate {
284  template <typename ITy> bool match(ITy *V) {
285    if (const auto *CF = dyn_cast<ConstantFP>(V))
286      return this->isValue(CF->getValueAPF());
287    if (V->getType()->isVectorTy()) {
288      if (const auto *C = dyn_cast<Constant>(V)) {
289        if (const auto *CF = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
290          return this->isValue(CF->getValueAPF());
291 
292        // Non-splat vector constant: check each element for a match.
293        unsigned NumElts = V->getType()->getVectorNumElements();
294        assert(NumElts != 0 && "Constant vector with no elements?")((NumElts != 0 && "Constant vector with no elements?"
) ? static_cast<void> (0) : __assert_fail ("NumElts != 0 && \"Constant vector with no elements?\""
, "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/include/llvm/IR/PatternMatch.h"
, 294, __PRETTY_FUNCTION__));
295        bool HasNonUndefElements = false;
296        for (unsigned i = 0; i != NumElts; ++i) {
297          Constant *Elt = C->getAggregateElement(i);
298          if (!Elt)
299            return false;
300          if (isa<UndefValue>(Elt))
301            continue;
302          auto *CF = dyn_cast<ConstantFP>(Elt);
303          if (!CF || !this->isValue(CF->getValueAPF()))
304            return false;
305          HasNonUndefElements = true;
306        }
307        return HasNonUndefElements;
308      }
309    }
310    return false;
311  }
312};
313 
314///////////////////////////////////////////////////////////////////////////////
315//
316// Encapsulate constant value queries for use in templated predicate matchers.
317// This allows checking if constants match using compound predicates and works
318// with vector constants, possibly with relaxed constraints. For example, ignore
319// undef values.
320//
321///////////////////////////////////////////////////////////////////////////////
322 
323struct is_any_apint {
324  bool isValue(const APInt &C) { return true; }
325};
326/// Match an integer or vector with any integral constant.
327/// For vectors, this includes constants with undefined elements.
328inline cst_pred_ty<is_any_apint> m_AnyIntegralConstant() {
329  return cst_pred_ty<is_any_apint>();
330}
331 
332struct is_all_ones {
333  bool isValue(const APInt &C) { return C.isAllOnesValue(); }
334};
335/// Match an integer or vector with all bits set.
336/// For vectors, this includes constants with undefined elements.
337inline cst_pred_ty<is_all_ones> m_AllOnes() {
338  return cst_pred_ty<is_all_ones>();
339}
340 
341struct is_maxsignedvalue {
342  bool isValue(const APInt &C) { return C.isMaxSignedValue(); }
343};
344/// Match an integer or vector with values having all bits except for the high
345/// bit set (0x7f...).
346/// For vectors, this includes constants with undefined elements.
347inline cst_pred_ty<is_maxsignedvalue> m_MaxSignedValue() {
348  return cst_pred_ty<is_maxsignedvalue>();
349}
350inline api_pred_ty<is_maxsignedvalue> m_MaxSignedValue(const APInt *&V) {
351  return V;
352}
353 
354struct is_negative {
355  bool isValue(const APInt &C) { return C.isNegative(); }
356};
357/// Match an integer or vector of negative values.
358/// For vectors, this includes constants with undefined elements.
359inline cst_pred_ty<is_negative> m_Negative() {
360  return cst_pred_ty<is_negative>();
361}
362inline api_pred_ty<is_negative> m_Negative(const APInt *&V) {
363  return V;
364}
365 
366struct is_nonnegative {
367  bool isValue(const APInt &C) { return C.isNonNegative(); }
368};
369/// Match an integer or vector of non-negative values.
370/// For vectors, this includes constants with undefined elements.
371inline cst_pred_ty<is_nonnegative> m_NonNegative() {
372  return cst_pred_ty<is_nonnegative>();
373}
374inline api_pred_ty<is_nonnegative> m_NonNegative(const APInt *&V) {
375  return V;
376}
377 
378struct is_strictlypositive {
379  bool isValue(const APInt &C) { return C.isStrictlyPositive(); }
380};
381/// Match an integer or vector of strictly positive values.
382/// For vectors, this includes constants with undefined elements.
383inline cst_pred_ty<is_strictlypositive> m_StrictlyPositive() {
384  return cst_pred_ty<is_strictlypositive>();
385}
386inline api_pred_ty<is_strictlypositive> m_StrictlyPositive(const APInt *&V) {
387  return V;
388}
389 
390struct is_nonpositive {
391  bool isValue(const APInt &C) { return C.isNonPositive(); }
392};
393/// Match an integer or vector of non-positive values.
394/// For vectors, this includes constants with undefined elements.
395inline cst_pred_ty<is_nonpositive> m_NonPositive() {
396  return cst_pred_ty<is_nonpositive>();
397}
398inline api_pred_ty<is_nonpositive> m_NonPositive(const APInt *&V) { return V; }
399 
400struct is_one {
401  bool isValue(const APInt &C) { return C.isOneValue(); }
402};
403/// Match an integer 1 or a vector with all elements equal to 1.
404/// For vectors, this includes constants with undefined elements.
405inline cst_pred_ty<is_one> m_One() {
406  return cst_pred_ty<is_one>();
407}
408 
409struct is_zero_int {
410  bool isValue(const APInt &C) { return C.isNullValue(); }
411};
412/// Match an integer 0 or a vector with all elements equal to 0.
413/// For vectors, this includes constants with undefined elements.
414inline cst_pred_ty<is_zero_int> m_ZeroInt() {
415  return cst_pred_ty<is_zero_int>();
416}
417 
418struct is_zero {
419  template <typename ITy> bool match(ITy *V) {
420    auto *C = dyn_cast<Constant>(V);
421    return C && (C->isNullValue() || cst_pred_ty<is_zero_int>().match(C));
422  }
423};
424/// Match any null constant or a vector with all elements equal to 0.
425/// For vectors, this includes constants with undefined elements.
426inline is_zero m_Zero() {
427  return is_zero();
428}
429 
430struct is_power2 {
431  bool isValue(const APInt &C) { return C.isPowerOf2(); }
432};
433/// Match an integer or vector power-of-2.
434/// For vectors, this includes constants with undefined elements.
435inline cst_pred_ty<is_power2> m_Power2() {
436  return cst_pred_ty<is_power2>();
437}
438inline api_pred_ty<is_power2> m_Power2(const APInt *&V) {
439  return V;
440}
441 
442struct is_negated_power2 {
443  bool isValue(const APInt &C) { return (-C).isPowerOf2(); }
444};
445/// Match a integer or vector negated power-of-2.
446/// For vectors, this includes constants with undefined elements.
447inline cst_pred_ty<is_negated_power2> m_NegatedPower2() {
448  return cst_pred_ty<is_negated_power2>();
449}
450inline api_pred_ty<is_negated_power2> m_NegatedPower2(const APInt *&V) {
451  return V;
452}
453 
454struct is_power2_or_zero {
455  bool isValue(const APInt &C) { return !C || C.isPowerOf2(); }
456};
457/// Match an integer or vector of 0 or power-of-2 values.
458/// For vectors, this includes constants with undefined elements.
459inline cst_pred_ty<is_power2_or_zero> m_Power2OrZero() {
460  return cst_pred_ty<is_power2_or_zero>();
461}
462inline api_pred_ty<is_power2_or_zero> m_Power2OrZero(const APInt *&V) {
463  return V;
464}
465 
466struct is_sign_mask {
467  bool isValue(const APInt &C) { return C.isSignMask(); }
468};
469/// Match an integer or vector with only the sign bit(s) set.
470/// For vectors, this includes constants with undefined elements.
471inline cst_pred_ty<is_sign_mask> m_SignMask() {
472  return cst_pred_ty<is_sign_mask>();
473}
474 
475struct is_lowbit_mask {
476  bool isValue(const APInt &C) { return C.isMask(); }
477};
478/// Match an integer or vector with only the low bit(s) set.
479/// For vectors, this includes constants with undefined elements.
480inline cst_pred_ty<is_lowbit_mask> m_LowBitMask() {
481  return cst_pred_ty<is_lowbit_mask>();
482}
483 
484struct icmp_pred_with_threshold {
485  ICmpInst::Predicate Pred;
486  const APInt *Thr;
487  bool isValue(const APInt &C) {
488    switch (Pred) {
489    case ICmpInst::Predicate::ICMP_EQ:
490      return C.eq(*Thr);
491    case ICmpInst::Predicate::ICMP_NE:
492      return C.ne(*Thr);
493    case ICmpInst::Predicate::ICMP_UGT:
494      return C.ugt(*Thr);
495    case ICmpInst::Predicate::ICMP_UGE:
496      return C.uge(*Thr);
497    case ICmpInst::Predicate::ICMP_ULT:
498      return C.ult(*Thr);
499    case ICmpInst::Predicate::ICMP_ULE:
500      return C.ule(*Thr);
501    case ICmpInst::Predicate::ICMP_SGT:
502      return C.sgt(*Thr);
503    case ICmpInst::Predicate::ICMP_SGE:
504      return C.sge(*Thr);
505    case ICmpInst::Predicate::ICMP_SLT:
506      return C.slt(*Thr);
507    case ICmpInst::Predicate::ICMP_SLE:
508      return C.sle(*Thr);
509    default:
510      llvm_unreachable("Unhandled ICmp predicate")::llvm::llvm_unreachable_internal("Unhandled ICmp predicate",
 "/build/llvm-toolchain-snapshot-10~+20191219111111+200cce345dc/llvm/include/llvm/IR/PatternMatch.h"
, 510);
511    }
512  }
513};
514/// Match an integer or vector with every element comparing 'pred' (eg/ne/...)
515/// to Threshold. For vectors, this includes constants with undefined elements.
516inline cst_pred_ty<icmp_pred_with_threshold>
517m_SpecificInt_ICMP(ICmpInst::Predicate Predicate, const APInt &Threshold) {
518  cst_pred_ty<icmp_pred_with_threshold> P;
519  P.Pred = Predicate;
520  P.Thr = &Threshold;
521  return P;
522}
523 
524struct is_nan {
525  bool isValue(const APFloat &C) { return C.isNaN(); }
526};
527/// Match an arbitrary NaN constant. This includes quiet and signalling nans.
528/// For vectors, this includes constants with undefined elements.
529inline cstfp_pred_ty<is_nan> m_NaN() {
530  return cstfp_pred_ty<is_nan>();
531}
532 
533struct is_any_zero_fp {
534  bool isValue(const APFloat &C) { return C.isZero(); }
535};
536/// Match a floating-point negative zero or positive zero.
537/// For vectors, this includes constants with undefined elements.
538inline cstfp_pred_ty<is_any_zero_fp> m_AnyZeroFP() {
539  return cstfp_pred_ty<is_any_zero_fp>();
540}
541 
542struct is_pos_zero_fp {
543  bool isValue(const APFloat &C) { return C.isPosZero(); }
544};
545/// Match a floating-point positive zero.
546/// For vectors, this includes constants with undefined elements.
547inline cstfp_pred_ty<is_pos_zero_fp> m_PosZeroFP() {
548  return cstfp_pred_ty<is_pos_zero_fp>();
549}
550 
551struct is_neg_zero_fp {
552  bool isValue(const APFloat &C) { return C.isNegZero(); }
553};
554/// Match a floating-point negative zero.
555/// For vectors, this includes constants with undefined elements.
556inline cstfp_pred_ty<is_neg_zero_fp> m_NegZeroFP() {
557  return cstfp_pred_ty<is_neg_zero_fp>();
558}
559 
560///////////////////////////////////////////////////////////////////////////////
561 
562template <typename Class> struct bind_ty {
563  Class *&VR;
564 
565  bind_ty(Class *&V) : VR(V) {}
566 
567  template <typename ITy> bool match(ITy *V) {
568    if (auto *CV = dyn_cast<Class>(V)) {
569      VR = CV;
570      return true;
571    }
572    return false;
573  }
574};
575 
576/// Match a value, capturing it if we match.
577inline bind_ty<Value> m_Value(Value *&V) { return V; }
2
←
Calling constructor for 'bind_ty<llvm::Value>'→
3
←
Returning from constructor for 'bind_ty<llvm::Value>'→
4
←
Returning without writing to 'V'→
578inline bind_ty<const Value> m_Value(const Value *&V) { return V; }
579 
580/// Match an instruction, capturing it if we match.
581inline bind_ty<Instruction> m_Instruction(Instruction *&I) { return I; }
582/// Match a binary operator, capturing it if we match.
583inline bind_ty<BinaryOperator> m_BinOp(BinaryOperator *&I) { return I; }
584/// Match a with overflow intrinsic, capturing it if we match.
585inline bind_ty<WithOverflowInst> m_WithOverflowInst(WithOverflowInst *&I) { return I; }
586 
587/// Match a ConstantInt, capturing the value if we match.
588inline bind_ty<ConstantInt> m_ConstantInt(ConstantInt *&CI) { return CI; }
589 
590/// Match a Constant, capturing the value if we match.
591inline bind_ty<Constant> m_Constant(Constant *&C) { return C; }
592 
593/// Match a ConstantFP, capturing the value if we match.
594inline bind_ty<ConstantFP> m_ConstantFP(ConstantFP *&C) { return C; }
595 
596/// Match a basic block value, capturing it if we match.
597inline bind_ty<BasicBlock> m_BasicBlock(BasicBlock *&V) { return V; }
598inline bind_ty<const BasicBlock> m_BasicBlock(const BasicBlock *&V) {
599  return V;
600}
601 
602/// Match a specified Value*.
603struct specificval_ty {
604  const Value *Val;
605 
606  specificval_ty(const Value *V) : Val(V) {}
607 
608  template <typename ITy> bool match(ITy *V) { return V == Val; }
609};
610 
611/// Match if we have a specific specified value.
612inline specificval_ty m_Specific(const Value *V) { return V; }
613 
614/// Stores a reference to the Value *, not the Value * itself,
615/// thus can be used in commutative matchers.
616template <typename Class> struct deferredval_ty {
617  Class *const &Val;
618 
619  deferredval_ty(Class *const &V) : Val(V) {}
620 
621  template <typename ITy> bool match(ITy *const V) { return V == Val; }
622};
623 
624/// A commutative-friendly version of m_Specific().
625inline deferredval_ty<Value> m_Deferred(Value *const &V) { return V; }
626inline deferredval_ty<const Value> m_Deferred(const Value *const &V) {
627  return V;
628}
629 
630/// Match a specified floating point value or vector of all elements of
631/// that value.
632struct specific_fpval {
633  double Val;
634 
635  specific_fpval(double V) : Val(V) {}
636 
637  template <typename ITy> bool match(ITy *V) {
638    if (const auto *CFP = dyn_cast<ConstantFP>(V))
639      return CFP->isExactlyValue(Val);
640    if (V->getType()->isVectorTy())
641      if (const auto *C = dyn_cast<Constant>(V))
642        if (auto *CFP = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
643          return CFP->isExactlyValue(Val);
644    return false;
645  }
646};
647 
648/// Match a specific floating point value or vector with all elements
649/// equal to the value.
650inline specific_fpval m_SpecificFP(double V) { return specific_fpval(V); }
651 
652/// Match a float 1.0 or vector with all elements equal to 1.0.
653inline specific_fpval m_FPOne() { return m_SpecificFP(1.0); }
654 
655struct bind_const_intval_ty {
656  uint64_t &VR;
657 
658  bind_const_intval_ty(uint64_t &V) : VR(V) {}
659 
660  template <typename ITy> bool match(ITy *V) {
661    if (const auto *CV = dyn_cast<ConstantInt>(V))
662      if (CV->getValue().ule(UINT64_MAX(18446744073709551615UL))) {
663        VR = CV->getZExtValue();
664        return true;
665      }
666    return false;
667  }
668};
669 
670/// Match a specified integer value or vector of all elements of that
671/// value.
672struct specific_intval {
673  APInt Val;
674 
675  specific_intval(APInt V) : Val(std::move(V)) {}
676 
677  template <typename ITy> bool match(ITy *V) {
678    const auto *CI = dyn_cast<ConstantInt>(V);
679    if (!CI && V->getType()->isVectorTy())
680      if (const auto *C = dyn_cast<Constant>(V))
681        CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue());
682 
683    return CI && APInt::isSameValue(CI->getValue(), Val);
684  }
685};
686 
687/// Match a specific integer value or vector with all elements equal to
688/// the value.
689inline specific_intval m_SpecificInt(APInt V) {
690  return specific_intval(std::move(V));
691}
692 
693inline specific_intval m_SpecificInt(uint64_t V) {
694  return m_SpecificInt(APInt(64, V));
695}
696 
697/// Match a ConstantInt and bind to its value.  This does not match
698/// ConstantInts wider than 64-bits.
699inline bind_const_intval_ty m_ConstantInt(uint64_t &V) { return V; }
700 
701/// Match a specified basic block value.
702struct specific_bbval {
703  BasicBlock *Val;
704 
705  specific_bbval(BasicBlock *Val) : Val(Val) {}
706 
707  template <typename ITy> bool match(ITy *V) {
708    const auto *BB = dyn_cast<BasicBlock>(V);
709    return BB && BB == Val;
710  }
711};
712 
713/// Match a specific basic block value.
714inline specific_bbval m_SpecificBB(BasicBlock *BB) {
715  return specific_bbval(BB);
716}
717 
718/// A commutative-friendly version of m_Specific().
719inline deferredval_ty<BasicBlock> m_Deferred(BasicBlock *const &BB) {
720  return BB;
721}
722inline deferredval_ty<const BasicBlock>
723m_Deferred(const BasicBlock *const &BB) {
724  return BB;
725}
726 
727//===----------------------------------------------------------------------===//
728// Matcher for any binary operator.
729//
730template <typename LHS_t, typename RHS_t, bool Commutable = false>
731struct AnyBinaryOp_match {
732  LHS_t L;
733  RHS_t R;
734 
735  // The evaluation order is always stable, regardless of Commutability.
736  // The LHS is always matched first.
737  AnyBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
738 
739  template <typename OpTy> bool match(OpTy *V) {
740    if (auto *I = dyn_cast<BinaryOperator>(V))
741      return (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
742             (Commutable && L.match(I->getOperand(1)) &&
743              R.match(I->getOperand(0)));
744    return false;
745  }
746};
747 
748template <typename LHS, typename RHS>
749inline AnyBinaryOp_match<LHS, RHS> m_BinOp(const LHS &L, const RHS &R) {
750  return AnyBinaryOp_match<LHS, RHS>(L, R);
751}
752 
753//===----------------------------------------------------------------------===//
754// Matchers for specific binary operators.
755//
756 
757template <typename LHS_t, typename RHS_t, unsigned Opcode,
758          bool Commutable = false>
759struct BinaryOp_match {
760  LHS_t L;
761  RHS_t R;
762 
763  // The evaluation order is always stable, regardless of Commutability.
764  // The LHS is always matched first.
765  BinaryOp_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
766 
767  template <typename OpTy> bool match(OpTy *V) {
768    if (V->getValueID() == Value::InstructionVal + Opcode) {
19
←
Assuming the condition is true→
20
←
Taking true branch→
769      auto *I = cast<BinaryOperator>(V);
21
←
'V' is a 'BinaryOperator'→
770      return (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
22
←
Value assigned to 'X'→
23
←
Assuming the condition is true→
771             (Commutable && L.match(I->getOperand(1)) &&
772              R.match(I->getOperand(0)));
773    }
774    if (auto *CE = dyn_cast<ConstantExpr>(V))
775      return CE->getOpcode() == Opcode &&
776             ((L.match(CE->getOperand(0)) && R.match(CE->getOperand(1))) ||
777              (Commutable && L.match(CE->getOperand(1)) &&
778               R.match(CE->getOperand(0))));
779    return false;
780  }
781};
782 
783template <typename LHS, typename RHS>
784inline BinaryOp_match<LHS, RHS, Instruction::Add> m_Add(const LHS &L,
785                                                        const RHS &R) {
786  return BinaryOp_match<LHS, RHS, Instruction::Add>(L, R);
787}
788 
789template <typename LHS, typename RHS>
790inline BinaryOp_match<LHS, RHS, Instruction::FAdd> m_FAdd(const LHS &L,
791                                                          const RHS &R) {
792  return BinaryOp_match<LHS, RHS, Instruction::FAdd>(L, R);
793}
794 
795template <typename LHS, typename RHS>
796inline BinaryOp_match<LHS, RHS, Instruction::Sub> m_Sub(const LHS &L,
797                                                        const RHS &R) {
798  return BinaryOp_match<LHS, RHS, Instruction::Sub>(L, R);
799}
800 
801template <typename LHS, typename RHS>
802inline BinaryOp_match<LHS, RHS, Instruction::FSub> m_FSub(const LHS &L,
803                                                          const RHS &R) {
804  return BinaryOp_match<LHS, RHS, Instruction::FSub>(L, R);
805}
806 
807template <typename Op_t> struct FNeg_match {
808  Op_t X;
809 
810  FNeg_match(const Op_t &Op) : X(Op) {}
811  template <typename OpTy> bool match(OpTy *V) {
812    auto *FPMO = dyn_cast<FPMathOperator>(V);
813    if (!FPMO) return false;
814 
815    if (FPMO->getOpcode() == Instruction::FNeg)
816      return X.match(FPMO->getOperand(0));
817 
818    if (FPMO->getOpcode() == Instruction::FSub) {
819      if (FPMO->hasNoSignedZeros()) {
820        // With 'nsz', any zero goes.
821        if (!cstfp_pred_ty<is_any_zero_fp>().match(FPMO->getOperand(0)))
822          return false;
823      } else {
824        // Without 'nsz', we need fsub -0.0, X exactly.
825        if (!cstfp_pred_ty<is_neg_zero_fp>().match(FPMO->getOperand(0)))
826          return false;
827      }
828 
829      return X.match(FPMO->getOperand(1));
830    }
831 
832    return false;
833  }
834};
835 
836/// Match 'fneg X' as 'fsub -0.0, X'.
837template <typename OpTy>
838inline FNeg_match<OpTy>
839m_FNeg(const OpTy &X) {
840  return FNeg_match<OpTy>(X);
841}
842 
843/// Match 'fneg X' as 'fsub +-0.0, X'.
844template <typename RHS>
845inline BinaryOp_match<cstfp_pred_ty<is_any_zero_fp>, RHS, Instruction::FSub>
846m_FNegNSZ(const RHS &X) {
847  return m_FSub(m_AnyZeroFP(), X);
848}
849 
850template <typename LHS, typename RHS>
851inline BinaryOp_match<LHS, RHS, Instruction::Mul> m_Mul(const LHS &L,
852                                                        const RHS &R) {
853  return BinaryOp_match<LHS, RHS, Instruction::Mul>(L, R);
854}
855 
856template <typename LHS, typename RHS>
857inline BinaryOp_match<LHS, RHS, Instruction::FMul> m_FMul(const LHS &L,
858                                                          const RHS &R) {
859  return BinaryOp_match<LHS, RHS, Instruction::FMul>(L, R);
860}
861 
862template <typename LHS, typename RHS>
863inline BinaryOp_match<LHS, RHS, Instruction::UDiv> m_UDiv(const LHS &L,
864                                                          const RHS &R) {
865  return BinaryOp_match<LHS, RHS, Instruction::UDiv>(L, R);
866}
867 
868template <typename LHS, typename RHS>
869inline BinaryOp_match<LHS, RHS, Instruction::SDiv> m_SDiv(const LHS &L,
870                                                          const RHS &R) {
871  return BinaryOp_match<LHS, RHS, Instruction::SDiv>(L, R);
872}
873 
874template <typename LHS, typename RHS>
875inline BinaryOp_match<LHS, RHS, Instruction::FDiv> m_FDiv(const LHS &L,
876                                                          const RHS &R) {
877  return BinaryOp_match<LHS, RHS, Instruction::FDiv>(L, R);
878}
879 
880template <typename LHS, typename RHS>
881inline BinaryOp_match<LHS, RHS, Instruction::URem> m_URem(const LHS &L,
882                                                          const RHS &R) {
883  return BinaryOp_match<LHS, RHS, Instruction::URem>(L, R);
884}
885 
886template <typename LHS, typename RHS>
887inline BinaryOp_match<LHS, RHS, Instruction::SRem> m_SRem(const LHS &L,
888                                                          const RHS &R) {
889  return BinaryOp_match<LHS, RHS, Instruction::SRem>(L, R);
890}
891 
892template <typename LHS, typename RHS>
893inline BinaryOp_match<LHS, RHS, Instruction::FRem> m_FRem(const LHS &L,
894                                                          const RHS &R) {
895  return BinaryOp_match<LHS, RHS, Instruction::FRem>(L, R);
896}
897 
898template <typename LHS, typename RHS>
899inline BinaryOp_match<LHS, RHS, Instruction::And> m_And(const LHS &L,
900                                                        const RHS &R) {
901  return BinaryOp_match<LHS, RHS, Instruction::And>(L, R);
902}
903 
904template <typename LHS, typename RHS>
905inline BinaryOp_match<LHS, RHS, Instruction::Or> m_Or(const LHS &L,
906                                                      const RHS &R) {
907  return BinaryOp_match<LHS, RHS, Instruction::Or>(L, R);
908}
909 
910template <typename LHS, typename RHS>
911inline BinaryOp_match<LHS, RHS, Instruction::Xor> m_Xor(const LHS &L,
912                                                        const RHS &R) {
913  return BinaryOp_match<LHS, RHS, Instruction::Xor>(L, R);
914}
915 
916template <typename LHS, typename RHS>
917inline BinaryOp_match<LHS, RHS, Instruction::Shl> m_Shl(const LHS &L,
918                                                        const RHS &R) {
919  return BinaryOp_match<LHS, RHS, Instruction::Shl>(L, R);
920}
921 
922template <typename LHS, typename RHS>
923inline BinaryOp_match<LHS, RHS, Instruction::LShr> m_LShr(const LHS &L,
924                                                          const RHS &R) {
925  return BinaryOp_match<LHS, RHS, Instruction::LShr>(L, R);
926}
927 
928template <typename LHS, typename RHS>
929inline BinaryOp_match<LHS, RHS, Instruction::AShr> m_AShr(const LHS &L,
930                                                          const RHS &R) {
931  return BinaryOp_match<LHS, RHS, Instruction::AShr>(L, R);
932}
933 
934template <typename LHS_t, typename RHS_t, unsigned Opcode,
935          unsigned WrapFlags = 0>
936struct OverflowingBinaryOp_match {
937  LHS_t L;
938  RHS_t R;
939 
940  OverflowingBinaryOp_match(const LHS_t &LHS, const RHS_t &RHS)
941      : L(LHS), R(RHS) {}
942 
943  template <typename OpTy> bool match(OpTy *V) {
944    if (auto *Op = dyn_cast<OverflowingBinaryOperator>(V)) {
945      if (Op->getOpcode() != Opcode)
946        return false;
947      if (WrapFlags & OverflowingBinaryOperator::NoUnsignedWrap &&
948          !Op->hasNoUnsignedWrap())
949        return false;
950      if (WrapFlags & OverflowingBinaryOperator::NoSignedWrap &&
951          !Op->hasNoSignedWrap())
952        return false;
953      return L.match(Op->getOperand(0)) && R.match(Op->getOperand(1));
954    }
955    return false;
956  }
957};
958 
959template <typename LHS, typename RHS>
960inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
961                                 OverflowingBinaryOperator::NoSignedWrap>
962m_NSWAdd(const LHS &L, const RHS &R) {
963  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
964                                   OverflowingBinaryOperator::NoSignedWrap>(
965      L, R);
966}
967template <typename LHS, typename RHS>
968inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
969                                 OverflowingBinaryOperator::NoSignedWrap>
970m_NSWSub(const LHS &L, const RHS &R) {
971  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
972                                   OverflowingBinaryOperator::NoSignedWrap>(
973      L, R);
974}
975template <typename LHS, typename RHS>
976inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
977                                 OverflowingBinaryOperator::NoSignedWrap>
978m_NSWMul(const LHS &L, const RHS &R) {
979  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
980                                   OverflowingBinaryOperator::NoSignedWrap>(
981      L, R);
982}
983template <typename LHS, typename RHS>
984inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
985                                 OverflowingBinaryOperator::NoSignedWrap>
986m_NSWShl(const LHS &L, const RHS &R) {
987  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
988                                   OverflowingBinaryOperator::NoSignedWrap>(
989      L, R);
990}
991 
992template <typename LHS, typename RHS>
993inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
994                                 OverflowingBinaryOperator::NoUnsignedWrap>
995m_NUWAdd(const LHS &L, const RHS &R) {
996  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Add,
997                                   OverflowingBinaryOperator::NoUnsignedWrap>(
998      L, R);
999}
1000template <typename LHS, typename RHS>
1001inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
1002                                 OverflowingBinaryOperator::NoUnsignedWrap>
1003m_NUWSub(const LHS &L, const RHS &R) {
1004  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Sub,
1005                                   OverflowingBinaryOperator::NoUnsignedWrap>(
1006      L, R);
1007}
1008template <typename LHS, typename RHS>
1009inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
1010                                 OverflowingBinaryOperator::NoUnsignedWrap>
1011m_NUWMul(const LHS &L, const RHS &R) {
1012  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Mul,
1013                                   OverflowingBinaryOperator::NoUnsignedWrap>(
1014      L, R);
1015}
1016template <typename LHS, typename RHS>
1017inline OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
1018                                 OverflowingBinaryOperator::NoUnsignedWrap>
1019m_NUWShl(const LHS &L, const RHS &R) {
1020  return OverflowingBinaryOp_match<LHS, RHS, Instruction::Shl,
1021                                   OverflowingBinaryOperator::NoUnsignedWrap>(
1022      L, R);
1023}
1024 
1025//===----------------------------------------------------------------------===//
1026// Class that matches a group of binary opcodes.
1027//
1028template <typename LHS_t, typename RHS_t, typename Predicate>
1029struct BinOpPred_match : Predicate {
1030  LHS_t L;
1031  RHS_t R;
1032 
1033  BinOpPred_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
1034 
1035  template <typename OpTy> bool match(OpTy *V) {
1036    if (auto *I = dyn_cast<Instruction>(V))
1037      return this->isOpType(I->getOpcode()) && L.match(I->getOperand(0)) &&
1038             R.match(I->getOperand(1));
1039    if (auto *CE = dyn_cast<ConstantExpr>(V))
1040      return this->isOpType(CE->getOpcode()) && L.match(CE->getOperand(0)) &&
1041             R.match(CE->getOperand(1));
1042    return false;
1043  }
1044};
1045 
1046struct is_shift_op {
1047  bool isOpType(unsigned Opcode) { return Instruction::isShift(Opcode); }
1048};
1049 
1050struct is_right_shift_op {
1051  bool isOpType(unsigned Opcode) {
1052    return Opcode == Instruction::LShr || Opcode == Instruction::AShr;
1053  }
1054};
1055 
1056struct is_logical_shift_op {
1057  bool isOpType(unsigned Opcode) {
1058    return Opcode == Instruction::LShr || Opcode == Instruction::Shl;
1059  }
1060};
1061 
1062struct is_bitwiselogic_op {
1063  bool isOpType(unsigned Opcode) {
1064    return Instruction::isBitwiseLogicOp(Opcode);
1065  }
1066};
1067 
1068struct is_idiv_op {
1069  bool isOpType(unsigned Opcode) {
1070    return Opcode == Instruction::SDiv || Opcode == Instruction::UDiv;
1071  }
1072};
1073 
1074struct is_irem_op {
1075  bool isOpType(unsigned Opcode) {
1076    return Opcode == Instruction::SRem || Opcode == Instruction::URem;
1077  }
1078};
1079 
1080/// Matches shift operations.
1081template <typename LHS, typename RHS>
1082inline BinOpPred_match<LHS, RHS, is_shift_op> m_Shift(const LHS &L,
1083                                                      const RHS &R) {
1084  return BinOpPred_match<LHS, RHS, is_shift_op>(L, R);
1085}
1086 
1087/// Matches logical shift operations.
1088template <typename LHS, typename RHS>
1089inline BinOpPred_match<LHS, RHS, is_right_shift_op> m_Shr(const LHS &L,
1090                                                          const RHS &R) {
1091  return BinOpPred_match<LHS, RHS, is_right_shift_op>(L, R);
1092}
1093 
1094/// Matches logical shift operations.
1095template <typename LHS, typename RHS>
1096inline BinOpPred_match<LHS, RHS, is_logical_shift_op>
1097m_LogicalShift(const LHS &L, const RHS &R) {
1098  return BinOpPred_match<LHS, RHS, is_logical_shift_op>(L, R);
1099}
1100 
1101/// Matches bitwise logic operations.
1102template <typename LHS, typename RHS>
1103inline BinOpPred_match<LHS, RHS, is_bitwiselogic_op>
1104m_BitwiseLogic(const LHS &L, const RHS &R) {
1105  return BinOpPred_match<LHS, RHS, is_bitwiselogic_op>(L, R);
1106}
1107 
1108/// Matches integer division operations.
1109template <typename LHS, typename RHS>
1110inline BinOpPred_match<LHS, RHS, is_idiv_op> m_IDiv(const LHS &L,
1111                                                    const RHS &R) {
1112  return BinOpPred_match<LHS, RHS, is_idiv_op>(L, R);
1113}
1114 
1115/// Matches integer remainder operations.
1116template <typename LHS, typename RHS>
1117inline BinOpPred_match<LHS, RHS, is_irem_op> m_IRem(const LHS &L,
1118                                                    const RHS &R) {
1119  return BinOpPred_match<LHS, RHS, is_irem_op>(L, R);
1120}
1121 
1122//===----------------------------------------------------------------------===//
1123// Class that matches exact binary ops.
1124//
1125template <typename SubPattern_t> struct Exact_match {
1126  SubPattern_t SubPattern;
1127 
1128  Exact_match(const SubPattern_t &SP) : SubPattern(SP) {}
1129 
1130  template <typename OpTy> bool match(OpTy *V) {
1131    if (auto *PEO = dyn_cast<PossiblyExactOperator>(V))
1132      return PEO->isExact() && SubPattern.match(V);
1133    return false;
1134  }
1135};
1136 
1137template <typename T> inline Exact_match<T> m_Exact(const T &SubPattern) {
1138  return SubPattern;
1139}
1140 
1141//===----------------------------------------------------------------------===//
1142// Matchers for CmpInst classes
1143//
1144 
1145template <typename LHS_t, typename RHS_t, typename Class, typename PredicateTy,
1146          bool Commutable = false>
1147struct CmpClass_match {
1148  PredicateTy &Predicate;
1149  LHS_t L;
1150  RHS_t R;
1151 
1152  // The evaluation order is always stable, regardless of Commutability.
1153  // The LHS is always matched first.
1154  CmpClass_match(PredicateTy &Pred, const LHS_t &LHS, const RHS_t &RHS)
1155      : Predicate(Pred), L(LHS), R(RHS) {}
1156 
1157  template <typename OpTy> bool match(OpTy *V) {
1158    if (auto *I14.1
'I' is non-null
14.1
'I' is non-null
 = dyn_cast<Class>(V))
14
←
Assuming 'V' is a 'ICmpInst'→
15
←
Taking true branch→
1159      if ((L.match(I->getOperand(0)) && R.match(I->getOperand(1))) ||
16
←
Calling 'OneUse_match::match'→
25
←
Returning from 'OneUse_match::match'→
1160          (Commutable && L.match(I->getOperand(1)) &&
1161           R.match(I->getOperand(0)))) {
1162        Predicate = I->getPredicate();
1163        return true;
26
←
Returning the value 1, which participates in a condition later→
1164      }
1165    return false;
1166  }
1167};
1168 
1169template <typename LHS, typename RHS>
1170inline CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>
1171m_Cmp(CmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1172  return CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>(Pred, L, R);
1173}
1174 
1175template <typename LHS, typename RHS>
1176inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>
1177m_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1178  return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>(Pred, L, R);
1179}
1180 
1181template <typename LHS, typename RHS>
1182inline CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>
1183m_FCmp(FCmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1184  return CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>(Pred, L, R);
1185}
1186 
1187//===----------------------------------------------------------------------===//
1188// Matchers for instructions with a given opcode and number of operands.
1189//
1190 
1191/// Matches instructions with Opcode and three operands.
1192template <typename T0, unsigned Opcode> struct OneOps_match {
1193  T0 Op1;
1194 
1195  OneOps_match(const T0 &Op1) : Op1(Op1) {}
1196 
1197  template <typename OpTy> bool match(OpTy *V) {
1198    if (V->getValueID() == Value::InstructionVal + Opcode) {
1199      auto *I = cast<Instruction>(V);
1200      return Op1.match(I->getOperand(0));
1201    }
1202    return false;
1203  }
1204};
1205 
1206/// Matches instructions with Opcode and three operands.
1207template <typename T0, typename T1, unsigned Opcode> struct TwoOps_match {
1208  T0 Op1;
1209  T1 Op2;
1210 
1211  TwoOps_match(const T0 &Op1, const T1 &Op2) : Op1(Op1), Op2(Op2) {}
1212 
1213  template <typename OpTy> bool match(OpTy *V) {
1214    if (V->getValueID() == Value::InstructionVal + Opcode) {
1215      auto *I = cast<Instruction>(V);
1216      return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1));
1217    }
1218    return false;
1219  }
1220};
1221 
1222/// Matches instructions with Opcode and three operands.
1223template <typename T0, typename T1, typename T2, unsigned Opcode>
1224struct ThreeOps_match {
1225  T0 Op1;
1226  T1 Op2;
1227  T2 Op3;
1228 
1229  ThreeOps_match(const T0 &Op1, const T1 &Op2, const T2 &Op3)
1230      : Op1(Op1), Op2(Op2), Op3(Op3) {}
1231 
1232  template <typename OpTy> bool match(OpTy *V) {
1233    if (V->getValueID() == Value::InstructionVal + Opcode) {
1234      auto *I = cast<Instruction>(V);
1235      return Op1.match(I->getOperand(0)) && Op2.match(I->getOperand(1)) &&
1236             Op3.match(I->getOperand(2));
1237    }
1238    return false;
1239  }
1240};
1241 
1242/// Matches SelectInst.
1243template <typename Cond, typename LHS, typename RHS>
1244inline ThreeOps_match<Cond, LHS, RHS, Instruction::Select>
1245m_Select(const Cond &C, const LHS &L, const RHS &R) {
1246  return ThreeOps_match<Cond, LHS, RHS, Instruction::Select>(C, L, R);
1247}
1248 
1249/// This matches a select of two constants, e.g.:
1250/// m_SelectCst<-1, 0>(m_Value(V))
1251template <int64_t L, int64_t R, typename Cond>
1252inline ThreeOps_match<Cond, constantint_match<L>, constantint_match<R>,
1253                      Instruction::Select>
1254m_SelectCst(const Cond &C) {
1255  return m_Select(C, m_ConstantInt<L>(), m_ConstantInt<R>());
1256}
1257 
1258/// Matches FreezeInst.
1259template <typename OpTy>
1260inline OneOps_match<OpTy, Instruction::Freeze> m_Freeze(const OpTy &Op) {
1261  return OneOps_match<OpTy, Instruction::Freeze>(Op);
1262}
1263 
1264/// Matches InsertElementInst.
1265template <typename Val_t, typename Elt_t, typename Idx_t>
1266inline ThreeOps_match<Val_t, Elt_t, Idx_t, Instruction::InsertElement>
1267m_InsertElement(const Val_t &Val, const Elt_t &Elt, const Idx_t &Idx) {
1268  return ThreeOps_match<Val_t, Elt_t, Idx_t, Instruction::InsertElement>(
1269      Val, Elt, Idx);
1270}
1271 
1272/// Matches ExtractElementInst.
1273template <typename Val_t, typename Idx_t>
1274inline TwoOps_match<Val_t, Idx_t, Instruction::ExtractElement>
1275m_ExtractElement(const Val_t &Val, const Idx_t &Idx) {
1276  return TwoOps_match<Val_t, Idx_t, Instruction::ExtractElement>(Val, Idx);
1277}
1278 
1279/// Matches ShuffleVectorInst.
1280template <typename V1_t, typename V2_t, typename Mask_t>
1281inline ThreeOps_match<V1_t, V2_t, Mask_t, Instruction::ShuffleVector>
1282m_ShuffleVector(const V1_t &v1, const V2_t &v2, const Mask_t &m) {
1283  return ThreeOps_match<V1_t, V2_t, Mask_t, Instruction::ShuffleVector>(v1, v2,
1284                                                                        m);
1285}
1286 
1287/// Matches LoadInst.
1288template <typename OpTy>
1289inline OneOps_match<OpTy, Instruction::Load> m_Load(const OpTy &Op) {
1290  return OneOps_match<OpTy, Instruction::Load>(Op);
1291}
1292 
1293/// Matches StoreInst.
1294template <typename ValueOpTy, typename PointerOpTy>
1295inline TwoOps_match<ValueOpTy, PointerOpTy, Instruction::Store>
1296m_Store(const ValueOpTy &ValueOp, const PointerOpTy &PointerOp) {
1297  return TwoOps_match<ValueOpTy, PointerOpTy, Instruction::Store>(ValueOp,
1298                                                                  PointerOp);
1299}
1300 
1301//===----------------------------------------------------------------------===//
1302// Matchers for CastInst classes
1303//
1304 
1305template <typename Op_t, unsigned Opcode> struct CastClass_match {
1306  Op_t Op;
1307 
1308  CastClass_match(const Op_t &OpMatch) : Op(OpMatch) {}
1309 
1310  template <typename OpTy> bool match(OpTy *V) {
1311    if (auto *O = dyn_cast<Operator>(V))
1312      return O->getOpcode() == Opcode && Op.match(O->getOperand(0));
1313    return false;
1314  }
1315};
1316 
1317/// Matches BitCast.
1318template <typename OpTy>
1319inline CastClass_match<OpTy, Instruction::BitCast> m_BitCast(const OpTy &Op) {
1320  return CastClass_match<OpTy, Instruction::BitCast>(Op);
1321}
1322 
1323/// Matches PtrToInt.
1324template <typename OpTy>
1325inline CastClass_match<OpTy, Instruction::PtrToInt> m_PtrToInt(const OpTy &Op) {
1326  return CastClass_match<OpTy, Instruction::PtrToInt>(Op);
1327}
1328 
1329/// Matches Trunc.
1330template <typename OpTy>
1331inline CastClass_match<OpTy, Instruction::Trunc> m_Trunc(const OpTy &Op) {
1332  return CastClass_match<OpTy, Instruction::Trunc>(Op);
1333}
1334 
1335template <typename OpTy>
1336inline match_combine_or<CastClass_match<OpTy, Instruction::Trunc>, OpTy>
1337m_TruncOrSelf(const OpTy &Op) {
1338  return m_CombineOr(m_Trunc(Op), Op);
1339}
1340 
1341/// Matches SExt.
1342template <typename OpTy>
1343inline CastClass_match<OpTy, Instruction::SExt> m_SExt(const OpTy &Op) {
1344  return CastClass_match<OpTy, Instruction::SExt>(Op);
1345}
1346 
1347/// Matches ZExt.
1348template <typename OpTy>
1349inline CastClass_match<OpTy, Instruction::ZExt> m_ZExt(const OpTy &Op) {
1350  return CastClass_match<OpTy, Instruction::ZExt>(Op);
1351}
1352 
1353template <typename OpTy>
1354inline match_combine_or<CastClass_match<OpTy, Instruction::ZExt>, OpTy>
1355m_ZExtOrSelf(const OpTy &Op) {
1356  return m_CombineOr(m_ZExt(Op), Op);
1357}
1358 
1359template <typename OpTy>
1360inline match_combine_or<CastClass_match<OpTy, Instruction::SExt>, OpTy>
1361m_SExtOrSelf(const OpTy &Op) {
1362  return m_CombineOr(m_SExt(Op), Op);
1363}
1364 
1365template <typename OpTy>
1366inline match_combine_or<CastClass_match<OpTy, Instruction::ZExt>,
1367                        CastClass_match<OpTy, Instruction::SExt>>
1368m_ZExtOrSExt(const OpTy &Op) {
1369  return m_CombineOr(m_ZExt(Op), m_SExt(Op));
1370}
1371 
1372template <typename OpTy>
1373inline match_combine_or<
1374    match_combine_or<CastClass_match<OpTy, Instruction::ZExt>,
1375                     CastClass_match<OpTy, Instruction::SExt>>,
1376    OpTy>
1377m_ZExtOrSExtOrSelf(const OpTy &Op) {
1378  return m_CombineOr(m_ZExtOrSExt(Op), Op);
1379}
1380 
1381/// Matches UIToFP.
1382template <typename OpTy>
1383inline CastClass_match<OpTy, Instruction::UIToFP> m_UIToFP(const OpTy &Op) {
1384  return CastClass_match<OpTy, Instruction::UIToFP>(Op);
1385}
1386 
1387/// Matches SIToFP.
1388template <typename OpTy>
1389inline CastClass_match<OpTy, Instruction::SIToFP> m_SIToFP(const OpTy &Op) {
1390  return CastClass_match<OpTy, Instruction::SIToFP>(Op);
1391}
1392 
1393/// Matches FPTrunc
1394template <typename OpTy>
1395inline CastClass_match<OpTy, Instruction::FPTrunc> m_FPTrunc(const OpTy &Op) {
1396  return CastClass_match<OpTy, Instruction::FPTrunc>(Op);
1397}
1398 
1399/// Matches FPExt
1400template <typename OpTy>
1401inline CastClass_match<OpTy, Instruction::FPExt> m_FPExt(const OpTy &Op) {
1402  return CastClass_match<OpTy, Instruction::FPExt>(Op);
1403}
1404 
1405//===----------------------------------------------------------------------===//
1406// Matchers for control flow.
1407//
1408 
1409struct br_match {
1410  BasicBlock *&Succ;
1411 
1412  br_match(BasicBlock *&Succ) : Succ(Succ) {}
1413 
1414  template <typename OpTy> bool match(OpTy *V) {
1415    if (auto *BI = dyn_cast<BranchInst>(V))
1416      if (BI->isUnconditional()) {
1417        Succ = BI->getSuccessor(0);
1418        return true;
1419      }
1420    return false;
1421  }
1422};
1423 
1424inline br_match m_UnconditionalBr(BasicBlock *&Succ) { return br_match(Succ); }
1425 
1426template <typename Cond_t, typename TrueBlock_t, typename FalseBlock_t>
1427struct brc_match {
1428  Cond_t Cond;
1429  TrueBlock_t T;
1430  FalseBlock_t F;
1431 
1432  brc_match(const Cond_t &C, const TrueBlock_t &t, const FalseBlock_t &f)
1433      : Cond(C), T(t), F(f) {}
1434 
1435  template <typename OpTy> bool match(OpTy *V) {
1436    if (auto *BI = dyn_cast<BranchInst>(V))
1437      if (BI->isConditional() && Cond.match(BI->getCondition()))
1438        return T.match(BI->getSuccessor(0)) && F.match(BI->getSuccessor(1));
1439    return false;
1440  }
1441};
1442 
1443template <typename Cond_t>
1444inline brc_match<Cond_t, bind_ty<BasicBlock>, bind_ty<BasicBlock>>
1445m_Br(const Cond_t &C, BasicBlock *&T, BasicBlock *&F) {
1446  return brc_match<Cond_t, bind_ty<BasicBlock>, bind_ty<BasicBlock>>(
1447      C, m_BasicBlock(T), m_BasicBlock(F));
1448}
1449 
1450template <typename Cond_t, typename TrueBlock_t, typename FalseBlock_t>
1451inline brc_match<Cond_t, TrueBlock_t, FalseBlock_t>
1452m_Br(const Cond_t &C, const TrueBlock_t &T, const FalseBlock_t &F) {
1453  return brc_match<Cond_t, TrueBlock_t, FalseBlock_t>(C, T, F);
1454}
1455 
1456//===----------------------------------------------------------------------===//
1457// Matchers for max/min idioms, eg: "select (sgt x, y), x, y" -> smax(x,y).
1458//
1459 
1460template <typename CmpInst_t, typename LHS_t, typename RHS_t, typename Pred_t,
1461          bool Commutable = false>
1462struct MaxMin_match {
1463  LHS_t L;
1464  RHS_t R;
1465 
1466  // The evaluation order is always stable, regardless of Commutability.
1467  // The LHS is always matched first.
1468  MaxMin_match(const LHS_t &LHS, const RHS_t &RHS) : L(LHS), R(RHS) {}
1469 
1470  template <typename OpTy> bool match(OpTy *V) {
1471    // Look for "(x pred y) ? x : y" or "(x pred y) ? y : x".
1472    auto *SI = dyn_cast<SelectInst>(V);
1473    if (!SI)
1474      return false;
1475    auto *Cmp = dyn_cast<CmpInst_t>(SI->getCondition());
1476    if (!Cmp)
1477      return false;
1478    // At this point we have a select conditioned on a comparison.  Check that
1479    // it is the values returned by the select that are being compared.
1480    Value *TrueVal = SI->getTrueValue();
1481    Value *FalseVal = SI->getFalseValue();
1482    Value *LHS = Cmp->getOperand(0);
1483    Value *RHS = Cmp->getOperand(1);
1484    if ((TrueVal != LHS || FalseVal != RHS) &&
1485        (TrueVal != RHS || FalseVal != LHS))
1486      return false;
1487    typename CmpInst_t::Predicate Pred =
1488        LHS == TrueVal ? Cmp->getPredicate() : Cmp->getInversePredicate();
1489    // Does "(x pred y) ? x : y" represent the desired max/min operation?
1490    if (!Pred_t::match(Pred))
1491      return false;
1492    // It does!  Bind the operands.
1493    return (L.match(LHS) && R.match(RHS)) ||
1494           (Commutable && L.match(RHS) && R.match(LHS));
1495  }
1496};
1497 
1498/// Helper class for identifying signed max predicates.
1499struct smax_pred_ty {
1500  static bool match(ICmpInst::Predicate Pred) {
1501    return Pred == CmpInst::ICMP_SGT || Pred == CmpInst::ICMP_SGE;
1502  }
1503};
1504 
1505/// Helper class for identifying signed min predicates.
1506struct smin_pred_ty {
1507  static bool match(ICmpInst::Predicate Pred) {
1508    return Pred == CmpInst::ICMP_SLT || Pred == CmpInst::ICMP_SLE;
1509  }
1510};
1511 
1512/// Helper class for identifying unsigned max predicates.
1513struct umax_pred_ty {
1514  static bool match(ICmpInst::Predicate Pred) {
1515    return Pred == CmpInst::ICMP_UGT || Pred == CmpInst::ICMP_UGE;
1516  }
1517};
1518 
1519/// Helper class for identifying unsigned min predicates.
1520struct umin_pred_ty {
1521  static bool match(ICmpInst::Predicate Pred) {
1522    return Pred == CmpInst::ICMP_ULT || Pred == CmpInst::ICMP_ULE;
1523  }
1524};
1525 
1526/// Helper class for identifying ordered max predicates.
1527struct ofmax_pred_ty {
1528  static bool match(FCmpInst::Predicate Pred) {
1529    return Pred == CmpInst::FCMP_OGT || Pred == CmpInst::FCMP_OGE;
1530  }
1531};
1532 
1533/// Helper class for identifying ordered min predicates.
1534struct ofmin_pred_ty {
1535  static bool match(FCmpInst::Predicate Pred) {
1536    return Pred == CmpInst::FCMP_OLT || Pred == CmpInst::FCMP_OLE;
1537  }
1538};
1539 
1540/// Helper class for identifying unordered max predicates.
1541struct ufmax_pred_ty {
1542  static bool match(FCmpInst::Predicate Pred) {
1543    return Pred == CmpInst::FCMP_UGT || Pred == CmpInst::FCMP_UGE;
1544  }
1545};
1546 
1547/// Helper class for identifying unordered min predicates.
1548struct ufmin_pred_ty {
1549  static bool match(FCmpInst::Predicate Pred) {
1550    return Pred == CmpInst::FCMP_ULT || Pred == CmpInst::FCMP_ULE;
1551  }
1552};
1553 
1554template <typename LHS, typename RHS>
1555inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty> m_SMax(const LHS &L,
1556                                                             const RHS &R) {
1557  return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty>(L, R);
1558}
1559 
1560template <typename LHS, typename RHS>
1561inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty> m_SMin(const LHS &L,
1562                                                             const RHS &R) {
1563  return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty>(L, R);
1564}
1565 
1566template <typename LHS, typename RHS>
1567inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty> m_UMax(const LHS &L,
1568                                                             const RHS &R) {
1569  return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty>(L, R);
1570}
1571 
1572template <typename LHS, typename RHS>
1573inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty> m_UMin(const LHS &L,
1574                                                             const RHS &R) {
1575  return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty>(L, R);
1576}
1577 
1578/// Match an 'ordered' floating point maximum function.
1579/// Floating point has one special value 'NaN'. Therefore, there is no total
1580/// order. However, if we can ignore the 'NaN' value (for example, because of a
1581/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
1582/// semantics. In the presence of 'NaN' we have to preserve the original
1583/// select(fcmp(ogt/ge, L, R), L, R) semantics matched by this predicate.
1584///
1585///                         max(L, R)  iff L and R are not NaN
1586///  m_OrdFMax(L, R) =      R          iff L or R are NaN
1587template <typename LHS, typename RHS>
1588inline MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty> m_OrdFMax(const LHS &L,
1589                                                                 const RHS &R) {
1590  return MaxMin_match<FCmpInst, LHS, RHS, ofmax_pred_ty>(L, R);
1591}
1592 
1593/// Match an 'ordered' floating point minimum function.
1594/// Floating point has one special value 'NaN'. Therefore, there is no total
1595/// order. However, if we can ignore the 'NaN' value (for example, because of a
1596/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
1597/// semantics. In the presence of 'NaN' we have to preserve the original
1598/// select(fcmp(olt/le, L, R), L, R) semantics matched by this predicate.
1599///
1600///                         min(L, R)  iff L and R are not NaN
1601///  m_OrdFMin(L, R) =      R          iff L or R are NaN
1602template <typename LHS, typename RHS>
1603inline MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty> m_OrdFMin(const LHS &L,
1604                                                                 const RHS &R) {
1605  return MaxMin_match<FCmpInst, LHS, RHS, ofmin_pred_ty>(L, R);
1606}
1607 
1608/// Match an 'unordered' floating point maximum function.
1609/// Floating point has one special value 'NaN'. Therefore, there is no total
1610/// order. However, if we can ignore the 'NaN' value (for example, because of a
1611/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'maximum'
1612/// semantics. In the presence of 'NaN' we have to preserve the original
1613/// select(fcmp(ugt/ge, L, R), L, R) semantics matched by this predicate.
1614///
1615///                         max(L, R)  iff L and R are not NaN
1616///  m_UnordFMax(L, R) =    L          iff L or R are NaN
1617template <typename LHS, typename RHS>
1618inline MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>
1619m_UnordFMax(const LHS &L, const RHS &R) {
1620  return MaxMin_match<FCmpInst, LHS, RHS, ufmax_pred_ty>(L, R);
1621}
1622 
1623/// Match an 'unordered' floating point minimum function.
1624/// Floating point has one special value 'NaN'. Therefore, there is no total
1625/// order. However, if we can ignore the 'NaN' value (for example, because of a
1626/// 'no-nans-float-math' flag) a combination of a fcmp and select has 'minimum'
1627/// semantics. In the presence of 'NaN' we have to preserve the original
1628/// select(fcmp(ult/le, L, R), L, R) semantics matched by this predicate.
1629///
1630///                          min(L, R)  iff L and R are not NaN
1631///  m_UnordFMin(L, R) =     L          iff L or R are NaN
1632template <typename LHS, typename RHS>
1633inline MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>
1634m_UnordFMin(const LHS &L, const RHS &R) {
1635  return MaxMin_match<FCmpInst, LHS, RHS, ufmin_pred_ty>(L, R);
1636}
1637 
1638//===----------------------------------------------------------------------===//
1639// Matchers for overflow check patterns: e.g. (a + b) u< a
1640//
1641 
1642template <typename LHS_t, typename RHS_t, typename Sum_t>
1643struct UAddWithOverflow_match {
1644  LHS_t L;
1645  RHS_t R;
1646  Sum_t S;
1647 
1648  UAddWithOverflow_match(const LHS_t &L, const RHS_t &R, const Sum_t &S)
1649      : L(L), R(R), S(S) {}
1650 
1651  template <typename OpTy> bool match(OpTy *V) {
1652    Value *ICmpLHS, *ICmpRHS;
1653    ICmpInst::Predicate Pred;
1654    if (!m_ICmp(Pred, m_Value(ICmpLHS), m_Value(ICmpRHS)).match(V))
1655      return false;
1656 
1657    Value *AddLHS, *AddRHS;
1658    auto AddExpr = m_Add(m_Value(AddLHS), m_Value(AddRHS));
1659 
1660    // (a + b) u< a, (a + b) u< b
1661    if (Pred == ICmpInst::ICMP_ULT)
1662      if (AddExpr.match(ICmpLHS) && (ICmpRHS == AddLHS || ICmpRHS == AddRHS))
1663        return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
1664 
1665    // a >u (a + b), b >u (a + b)
1666    if (Pred == ICmpInst::ICMP_UGT)
1667      if (AddExpr.match(ICmpRHS) && (ICmpLHS == AddLHS || ICmpLHS == AddRHS))
1668        return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
1669 
1670    // Match special-case for increment-by-1.
1671    if (Pred == ICmpInst::ICMP_EQ) {
1672      // (a + 1) == 0
1673      // (1 + a) == 0
1674      if (AddExpr.match(ICmpLHS) && m_ZeroInt().match(ICmpRHS) &&
1675          (m_One().match(AddLHS) || m_One().match(AddRHS)))
1676        return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
1677      // 0 == (a + 1)
1678      // 0 == (1 + a)
1679      if (m_ZeroInt().match(ICmpLHS) && AddExpr.match(ICmpRHS) &&
1680          (m_One().match(AddLHS) || m_One().match(AddRHS)))
1681        return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
1682    }
1683 
1684    return false;
1685  }
1686};
1687 
1688/// Match an icmp instruction checking for unsigned overflow on addition.
1689///
1690/// S is matched to the addition whose result is being checked for overflow, and
1691/// L and R are matched to the LHS and RHS of S.
1692template <typename LHS_t, typename RHS_t, typename Sum_t>
1693UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>
1694m_UAddWithOverflow(const LHS_t &L, const RHS_t &R, const Sum_t &S) {
1695  return UAddWithOverflow_match<LHS_t, RHS_t, Sum_t>(L, R, S);
1696}
1697 
1698template <typename Opnd_t> struct Argument_match {
1699  unsigned OpI;
1700  Opnd_t Val;
1701 
1702  Argument_match(unsigned OpIdx, const Opnd_t &V) : OpI(OpIdx), Val(V) {}
1703 
1704  template <typename OpTy> bool match(OpTy *V) {
1705    // FIXME: Should likely be switched to use `CallBase`.
1706    if (const auto *CI = dyn_cast<CallInst>(V))
1707      return Val.match(CI->getArgOperand(OpI));
1708    return false;
1709  }
1710};
1711 
1712/// Match an argument.
1713template <unsigned OpI, typename Opnd_t>
1714inline Argument_match<Opnd_t> m_Argument(const Opnd_t &Op) {
1715  return Argument_match<Opnd_t>(OpI, Op);
1716}
1717 
1718/// Intrinsic matchers.
1719struct IntrinsicID_match {
1720  unsigned ID;
1721 
1722  IntrinsicID_match(Intrinsic::ID IntrID) : ID(IntrID) {}
1723 
1724  template <typename OpTy> bool match(OpTy *V) {
1725    if (const auto *CI = dyn_cast<CallInst>(V))
1726      if (const auto *F = CI->getCalledFunction())
1727        return F->getIntrinsicID() == ID;
1728    return false;
1729  }
1730};
1731 
1732/// Intrinsic matches are combinations of ID matchers, and argument
1733/// matchers. Higher arity matcher are defined recursively in terms of and-ing
1734/// them with lower arity matchers. Here's some convenient typedefs for up to
1735/// several arguments, and more can be added as needed
1736template <typename T0 = void, typename T1 = void, typename T2 = void,
1737          typename T3 = void, typename T4 = void, typename T5 = void,
1738          typename T6 = void, typename T7 = void, typename T8 = void,
1739          typename T9 = void, typename T10 = void>
1740struct m_Intrinsic_Ty;
1741template <typename T0> struct m_Intrinsic_Ty<T0> {
1742  using Ty = match_combine_and<IntrinsicID_match, Argument_match<T0>>;
1743};
1744template <typename T0, typename T1> struct m_Intrinsic_Ty<T0, T1> {
1745  using Ty =
1746      match_combine_and<typename m_Intrinsic_Ty<T0>::Ty, Argument_match<T1>>;
1747};
1748template <typename T0, typename T1, typename T2>
1749struct m_Intrinsic_Ty<T0, T1, T2> {
1750  using Ty =
1751      match_combine_and<typename m_Intrinsic_Ty<T0, T1>::Ty,
1752                        Argument_match<T2>>;
1753};
1754template <typename T0, typename T1, typename T2, typename T3>
1755struct m_Intrinsic_Ty<T0, T1, T2, T3> {
1756  using Ty =
1757      match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2>::Ty,
1758                        Argument_match<T3>>;
1759};
1760 
1761template <typename T0, typename T1, typename T2, typename T3, typename T4>
1762struct m_Intrinsic_Ty<T0, T1, T2, T3, T4> {
1763  using Ty = match_combine_and<typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty,
1764                               Argument_match<T4>>;
1765};
1766 
1767/// Match intrinsic calls like this:
1768/// m_Intrinsic<Intrinsic::fabs>(m_Value(X))
1769template <Intrinsic::ID IntrID> inline IntrinsicID_match m_Intrinsic() {
1770  return IntrinsicID_match(IntrID);
1771}
1772 
1773template <Intrinsic::ID IntrID, typename T0>
1774inline typename m_Intrinsic_Ty<T0>::Ty m_Intrinsic(const T0 &Op0) {
1775  return m_CombineAnd(m_Intrinsic<IntrID>(), m_Argument<0>(Op0));
1776}
1777 
1778template <Intrinsic::ID IntrID, typename T0, typename T1>
1779inline typename m_Intrinsic_Ty<T0, T1>::Ty m_Intrinsic(const T0 &Op0,
1780                                                       const T1 &Op1) {
1781  return m_CombineAnd(m_Intrinsic<IntrID>(Op0), m_Argument<1>(Op1));
1782}
1783 
1784template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2>
1785inline typename m_Intrinsic_Ty<T0, T1, T2>::Ty
1786m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2) {
1787  return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1), m_Argument<2>(Op2));
1788}
1789 
1790template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
1791          typename T3>
1792inline typename m_Intrinsic_Ty<T0, T1, T2, T3>::Ty
1793m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3) {
1794  return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2), m_Argument<3>(Op3));
1795}
1796 
1797template <Intrinsic::ID IntrID, typename T0, typename T1, typename T2,
1798          typename T3, typename T4>
1799inline typename m_Intrinsic_Ty<T0, T1, T2, T3, T4>::Ty
1800m_Intrinsic(const T0 &Op0, const T1 &Op1, const T2 &Op2, const T3 &Op3,
1801            const T4 &Op4) {
1802  return m_CombineAnd(m_Intrinsic<IntrID>(Op0, Op1, Op2, Op3),
1803                      m_Argument<4>(Op4));
1804}
1805 
1806// Helper intrinsic matching specializations.
1807template <typename Opnd0>
1808inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BitReverse(const Opnd0 &Op0) {
1809  return m_Intrinsic<Intrinsic::bitreverse>(Op0);
1810}
1811 
1812template <typename Opnd0>
1813inline typename m_Intrinsic_Ty<Opnd0>::Ty m_BSwap(const Opnd0 &Op0) {
1814  return m_Intrinsic<Intrinsic::bswap>(Op0);
1815}
1816 
1817template <typename Opnd0>
1818inline typename m_Intrinsic_Ty<Opnd0>::Ty m_FAbs(const Opnd0 &Op0) {
1819  return m_Intrinsic<Intrinsic::fabs>(Op0);
1820}
1821 
1822template <typename Opnd0>
1823inline typename m_Intrinsic_Ty<Opnd0>::Ty m_FCanonicalize(const Opnd0 &Op0) {
1824  return m_Intrinsic<Intrinsic::canonicalize>(Op0);
1825}
1826 
1827template <typename Opnd0, typename Opnd1>
1828inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMin(const Opnd0 &Op0,
1829                                                        const Opnd1 &Op1) {
1830  return m_Intrinsic<Intrinsic::minnum>(Op0, Op1);
1831}
1832 
1833template <typename Opnd0, typename Opnd1>
1834inline typename m_Intrinsic_Ty<Opnd0, Opnd1>::Ty m_FMax(const Opnd0 &Op0,
1835                                                        const Opnd1 &Op1) {
1836  return m_Intrinsic<Intrinsic::maxnum>(Op0, Op1);
1837}
1838 
1839//===----------------------------------------------------------------------===//
1840// Matchers for two-operands operators with the operators in either order
1841//
1842 
1843/// Matches a BinaryOperator with LHS and RHS in either order.
1844template <typename LHS, typename RHS>
1845inline AnyBinaryOp_match<LHS, RHS, true> m_c_BinOp(const LHS &L, const RHS &R) {
1846  return AnyBinaryOp_match<LHS, RHS, true>(L, R);
1847}
1848 
1849/// Matches an ICmp with a predicate over LHS and RHS in either order.
1850/// Does not swap the predicate.
1851template <typename LHS, typename RHS>
1852inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate, true>
1853m_c_ICmp(ICmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
1854  return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate, true>(Pred, L,
7
←
Calling constructor for 'CmpClass_match<llvm::PatternMatch::OneUse_match<llvm::PatternMatch::BinaryOp_match<llvm::PatternMatch::cst_pred_ty<llvm::PatternMatch::is_one>, llvm::PatternMatch::bind_ty<llvm::Value>, 25, false> >, llvm::PatternMatch::bind_ty<llvm::Value>, llvm::ICmpInst, llvm::CmpInst::Predicate, true>'→
8
←
Returning from constructor for 'CmpClass_match<llvm::PatternMatch::OneUse_match<llvm::PatternMatch::BinaryOp_match<llvm::PatternMatch::cst_pred_ty<llvm::PatternMatch::is_one>, llvm::PatternMatch::bind_ty<llvm::Value>, 25, false> >, llvm::PatternMatch::bind_ty<llvm::Value>, llvm::ICmpInst, llvm::CmpInst::Predicate, true>'→
9
←
Returning without writing to 'Pred', which participates in a condition later→
10
←
Returning without writing to 'R.VR'→
1855                                                                       R);
1856}
1857 
1858/// Matches a Add with LHS and RHS in either order.
1859template <typename LHS, typename RHS>
1860inline BinaryOp_match<LHS, RHS, Instruction::Add, true> m_c_Add(const LHS &L,
1861                                                                const RHS &R) {
1862  return BinaryOp_match<LHS, RHS, Instruction::Add, true>(L, R);
1863}
1864 
1865/// Matches a Mul with LHS and RHS in either order.
1866template <typename LHS, typename RHS>
1867inline BinaryOp_match<LHS, RHS, Instruction::Mul, true> m_c_Mul(const LHS &L,
1868                                                                const RHS &R) {
1869  return BinaryOp_match<LHS, RHS, Instruction::Mul, true>(L, R);
1870}
1871 
1872/// Matches an And with LHS and RHS in either order.
1873template <typename LHS, typename RHS>
1874inline BinaryOp_match<LHS, RHS, Instruction::And, true> m_c_And(const LHS &L,
1875                                                                const RHS &R) {
1876  return BinaryOp_match<LHS, RHS, Instruction::And, true>(L, R);
1877}
1878 
1879/// Matches an Or with LHS and RHS in either order.
1880template <typename LHS, typename RHS>
1881inline BinaryOp_match<LHS, RHS, Instruction::Or, true> m_c_Or(const LHS &L,
1882                                                              const RHS &R) {
1883  return BinaryOp_match<LHS, RHS, Instruction::Or, true>(L, R);
1884}
1885 
1886/// Matches an Xor with LHS and RHS in either order.
1887template <typename LHS, typename RHS>
1888inline BinaryOp_match<LHS, RHS, Instruction::Xor, true> m_c_Xor(const LHS &L,
1889                                                                const RHS &R) {
1890  return BinaryOp_match<LHS, RHS, Instruction::Xor, true>(L, R);
1891}
1892 
1893/// Matches a 'Neg' as 'sub 0, V'.
1894template <typename ValTy>
1895inline BinaryOp_match<cst_pred_ty<is_zero_int>, ValTy, Instruction::Sub>
1896m_Neg(const ValTy &V) {
1897  return m_Sub(m_ZeroInt(), V);
1898}
1899 
1900/// Matches a 'Not' as 'xor V, -1' or 'xor -1, V'.
1901template <typename ValTy>
1902inline BinaryOp_match<ValTy, cst_pred_ty<is_all_ones>, Instruction::Xor, true>
1903m_Not(const ValTy &V) {
1904  return m_c_Xor(V, m_AllOnes());
1905}
1906 
1907/// Matches an SMin with LHS and RHS in either order.
1908template <typename LHS, typename RHS>
1909inline MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>
1910m_c_SMin(const LHS &L, const RHS &R) {
1911  return MaxMin_match<ICmpInst, LHS, RHS, smin_pred_ty, true>(L, R);
1912}
1913/// Matches an SMax with LHS and RHS in either order.
1914template <typename LHS, typename RHS>
1915inline MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>
1916m_c_SMax(const LHS &L, const RHS &R) {
1917  return MaxMin_match<ICmpInst, LHS, RHS, smax_pred_ty, true>(L, R);
1918}
1919/// Matches a UMin with LHS and RHS in either order.
1920template <typename LHS, typename RHS>
1921inline MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>
1922m_c_UMin(const LHS &L, const RHS &R) {
1923  return MaxMin_match<ICmpInst, LHS, RHS, umin_pred_ty, true>(L, R);
1924}
1925/// Matches a UMax with LHS and RHS in either order.
1926template <typename LHS, typename RHS>
1927inline MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>
1928m_c_UMax(const LHS &L, const RHS &R) {
1929  return MaxMin_match<ICmpInst, LHS, RHS, umax_pred_ty, true>(L, R);
1930}
1931 
1932/// Matches FAdd with LHS and RHS in either order.
1933template <typename LHS, typename RHS>
1934inline BinaryOp_match<LHS, RHS, Instruction::FAdd, true>
1935m_c_FAdd(const LHS &L, const RHS &R) {
1936  return BinaryOp_match<LHS, RHS, Instruction::FAdd, true>(L, R);
1937}
1938 
1939/// Matches FMul with LHS and RHS in either order.
1940template <typename LHS, typename RHS>
1941inline BinaryOp_match<LHS, RHS, Instruction::FMul, true>
1942m_c_FMul(const LHS &L, const RHS &R) {
1943  return BinaryOp_match<LHS, RHS, Instruction::FMul, true>(L, R);
1944}
1945 
1946template <typename Opnd_t> struct Signum_match {
1947  Opnd_t Val;
1948  Signum_match(const Opnd_t &V) : Val(V) {}
1949 
1950  template <typename OpTy> bool match(OpTy *V) {
1951    unsigned TypeSize = V->getType()->getScalarSizeInBits();
1952    if (TypeSize == 0)
1953      return false;
1954 
1955    unsigned ShiftWidth = TypeSize - 1;
1956    Value *OpL = nullptr, *OpR = nullptr;
1957 
1958    // This is the representation of signum we match:
1959    //
1960    //  signum(x) == (x >> 63) | (-x >>u 63)
1961    //
1962    // An i1 value is its own signum, so it's correct to match
1963    //
1964    //  signum(x) == (x >> 0)  | (-x >>u 0)
1965    //
1966    // for i1 values.
1967 
1968    auto LHS = m_AShr(m_Value(OpL), m_SpecificInt(ShiftWidth));
1969    auto RHS = m_LShr(m_Neg(m_Value(OpR)), m_SpecificInt(ShiftWidth));
1970    auto Signum = m_Or(LHS, RHS);
1971 
1972    return Signum.match(V) && OpL == OpR && Val.match(OpL);
1973  }
1974};
1975 
1976/// Matches a signum pattern.
1977///
1978/// signum(x) =
1979///      x >  0  ->  1
1980///      x == 0  ->  0
1981///      x <  0  -> -1
1982template <typename Val_t> inline Signum_match<Val_t> m_Signum(const Val_t &V) {
1983  return Signum_match<Val_t>(V);
1984}
1985 
1986template <int Ind, typename Opnd_t> struct ExtractValue_match {
1987  Opnd_t Val;
1988  ExtractValue_match(const Opnd_t &V) : Val(V) {}
1989 
1990  template <typename OpTy> bool match(OpTy *V) {
1991    if (auto *I = dyn_cast<ExtractValueInst>(V))
1992      return I->getNumIndices() == 1 && I->getIndices()[0] == Ind &&
1993             Val.match(I->getAggregateOperand());
1994    return false;
1995  }
1996};
1997 
1998/// Match a single index ExtractValue instruction.
1999/// For example m_ExtractValue<1>(...)
2000template <int Ind, typename Val_t>
2001inline ExtractValue_match<Ind, Val_t> m_ExtractValue(const Val_t &V) {
2002  return ExtractValue_match<Ind, Val_t>(V);
2003}
2004 
2005} // end namespace PatternMatch
2006} // end namespace llvm
2007 
2008#endif // LLVM_IR_PATTERNMATCH_H