/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

Bug Summary

File:	llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
Warning:	line 556, column 14 Called C++ object pointer is null

Annotated Source Code

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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"
27#include "llvm/Transforms/InstCombine/InstCombiner.h"

29using namespace llvm;
30using namespace PatternMatch;

32#define DEBUG_TYPE"instcombine" "instcombine"

34// How many times is a select replaced by one of its operands?
35STATISTIC(NumSel, "Number of select opts")static llvm::Statistic NumSel = {"instcombine", "NumSel", "Number of select opts"
};


38/// Compute Result = In1+In2, returning true if the result overflowed for this
39/// type.
40static 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;
49}

51/// Compute Result = In1-In2, returning true if the result overflowed for this
52/// type.
53static 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;
62}

64/// Given an icmp instruction, return true if any use of this comparison is a
65/// branch on sign bit comparison.
66static bool hasBranchUse(ICmpInst &I) {
for (auto *U : I.users())
  if (isa<BranchInst>(U))
    return true;
return false;
71}

73/// Returns true if the exploded icmp can be expressed as a signed comparison
74/// to zero and updates the predicate accordingly.
75/// The signedness of the comparison is preserved.
76/// TODO: Refactor with decomposeBitTestICmp()?
77static 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;
97}

99/// Given a signed integer type and a set of known zero and one bits, compute
100/// the maximum and minimum values that could have the specified known zero and
101/// known one bits, returning them in Min/Max.
102/// TODO: Move to method on KnownBits struct?
103static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 107, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 107, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 107, __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();
}
119}

121/// Given an unsigned integer type and a set of known zero and one bits, compute
122/// the maximum and minimum values that could have the specified known zero and
123/// known one bits, returning them in Min/Max.
124/// TODO: Move to method on KnownBits struct?
125static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 129, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 129, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 129, __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;
136}

138/// This is called when we see this pattern:
139///   cmp pred (load (gep GV, ...)), cmpcst
140/// where GV is a global variable with a constant initializer. Try to simplify
141/// this into some simple computation that does not need the load. For example
142/// we can optimize "icmp eq (load (gep "foo", 0, i)), 0" into "icmp eq i, 3".
143///
144/// If AndCst is non-null, then the loaded value is masked with that constant
145/// before doing the comparison. This handles cases like "A[i]&4 == 0".
146Instruction *
147InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 364, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 379, __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;
414}

416/// Return a value that can be used to compare the *offset* implied by a GEP to
417/// zero. For example, if we have &A[i], we want to return 'i' for
418/// "icmp ne i, 0". Note that, in general, indices can be complex, and scales
419/// are involved. The above expression would also be legal to codegen as
420/// "icmp ne (i*4), 0" (assuming A is a pointer to i32).
421/// This latter form is less amenable to optimization though, and we are allowed
422/// to generate the first by knowing that pointer arithmetic doesn't overflow.
423///
424/// If we can't emit an optimized form for this expression, this returns null.
425///
426static Value *evaluateGEPOffsetExpression(User *GEP, InstCombinerImpl &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");
515}

517/// Returns true if we can rewrite Start as a GEP with pointer Base
518/// and some integer offset. The nodes that need to be re-written
519/// for this transformation will be added to Explored.
520static 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()) {
43
←
Calling 'SmallVectorBase::empty'→
46
←
Returning from 'SmallVectorBase::empty'→
47
←
Loop condition is true.  Entering loop body→
  SetVector<PHINode *> PHIs;

  while (!WorkList.empty()) {
48
←
Calling 'SmallVectorBase::empty'→
50
←
Returning from 'SmallVectorBase::empty'→
51
←
Loop condition is true.  Entering loop body→
    if (Explored.size() >= 100)
52
←
Assuming the condition is false→
53
←
Taking false branch→
      return false;

    Value *V = WorkList.back();

    if (Explored.count(V) != 0) {
54
←
Assuming the condition is false→
55
←
Taking false branch→
      WorkList.pop_back();
      continue;
    }

    if (!isa<IntToPtrInst>(V) && !isa<PtrToIntInst>(V) &&
56
←
Assuming 'V' is not a 'IntToPtrInst'→
57
←
Assuming 'V' is not a 'PtrToIntInst'→
60
←
Taking false branch→
        !isa<GetElementPtrInst>(V) && !isa<PHINode>(V))
58
←
Assuming 'V' is not a 'GetElementPtrInst'→
59
←
Assuming 'V' is a 'PHINode'→
      // 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)) {
61
←
Assuming 'V' is not a 'IntToPtrInst'→
62
←
Assuming 'V' is a 'PtrToIntInst'→
63
←
Taking true branch→
      auto *CI = dyn_cast<CastInst>(V);
64
←
Assuming 'V' is not a 'CastInst'→
65
←
'CI' initialized to a null pointer value→
      if (!CI->isNoopCast(DL))
66
←
Called C++ object pointer is null
        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;
615}

617// Sets the appropriate insert point on Builder where we can add
618// a replacement Instruction for V (if that is possible).
619static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 639, __PRETTY_FUNCTION__));
640}

642/// Returns a re-written value of Start as an indexed GEP using Base as a
643/// pointer.
644static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 709);
}

// 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];
758}

760/// Looks through GEPs, IntToPtrInsts and PtrToIntInsts in order to express
761/// the input Value as a constant indexed GEP. Returns a pair containing
762/// the GEPs Pointer and Index.
763static std::pair<Value *, Value *>
764getAsConstantIndexedAddress(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};
800}

802/// Converts (CMP GEPLHS, RHS) if this change would make RHS a constant.
803/// We can look through PHIs, GEPs and casts in order to determine a common base
804/// between GEPLHS and RHS.
805static Instruction *transformToIndexedCompare(GEPOperator *GEPLHS, Value *RHS,
                                            ICmpInst::Predicate Cond,
                                            const DataLayout &DL) {
// FIXME: Support vector of pointers.
if (GEPLHS->getType()->isVectorTy())
38
←
Taking false branch→
  return nullptr;

if (!GEPLHS->hasAllConstantIndices())
39
←
Taking false branch→
  return nullptr;

// Make sure the pointers have the same type.
if (GEPLHS->getType() != RHS->getType())
40
←
Assuming the condition is false→
41
←
Taking false branch→
  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))
42
←
Calling 'canRewriteGEPAsOffset'→
  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);
841}

843/// Fold comparisons between a GEP instruction and something else. At this point
844/// we know that the GEP is on the LHS of the comparison.
845Instruction *InstCombinerImpl::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))
29
←
Assuming the condition is false→
30
←
Taking false branch→
  return nullptr;

// Look through bitcasts and addrspacecasts. We do not however want to remove
// 0 GEPs.
if (!isa<GetElementPtrInst>(RHS))
31
←
Assuming 'RHS' is not a 'GetElementPtrInst'→
32
←
Taking true branch→
  RHS = RHS->stripPointerCasts();

Value *PtrBase = GEPLHS->getOperand(0);
// FIXME: Support vector pointer GEPs.
if (PtrBase == RHS && GEPLHS->isInBounds() &&
33
←
Assuming 'PtrBase' is not equal to 'RHS'→
    !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) &&
34
←
Assuming the condition is false→
    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 = cast<FixedVectorType>(GEPLHS->getType())->getNumElements();
    Base = Builder.CreateVectorSplat(NumElts, Base);
  }
  return new ICmpInst(Cond, Base,
                      ConstantExpr::getPointerBitCastOrAddrSpaceCast(
                          cast<Constant>(RHS), Base->getType()));
} else if (GEPOperator *GEPRHS35.1
'GEPRHS' is null
1
'GEPRHS' is null
 = dyn_cast<GEPOperator>(RHS)) {
35
←
Assuming 'RHS' is not a 'GEPOperator'→
36
←
Taking false branch→
  // 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);
37
←
Calling 'transformToIndexedCompare'→
1023}

1025Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1028, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1055, __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())));
1100}

1102/// Fold "icmp pred (X+C), X".
1103Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1108, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1145, __PRETTY_FUNCTION__));
return new ICmpInst(ICmpInst::ICMP_SLT, X,
                    ConstantInt::get(X->getType(), SMax - (C - 1)));
1148}

1150/// Handle "(icmp eq/ne (ashr/lshr AP2, A), AP1)" ->
1151/// (icmp eq/ne A, Log2(AP2/AP1)) ->
1152/// (icmp eq/ne A, Log2(AP2) - Log2(AP1)).
1153Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1156, __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);
1208}

1210/// Handle "(icmp eq/ne (shl AP2, A), AP1)" ->
1211/// (icmp eq/ne A, TrailingZeros(AP1) - TrailingZeros(AP2)).
1212Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1215, __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);
1247}

1249/// The caller has matched a pattern of the form:
1250///   I = icmp ugt (add (add A, B), CI2), CI1
1251/// If this is of the form:
1252///   sum = a + b
1253///   if (sum+128 >u 255)
1254/// Then replace it with llvm.sadd.with.overflow.i8.
1255///
1256static Instruction *processUGT_ADDCST_ADD(ICmpInst &I, Value *A, Value *B,
                                        ConstantInt *CI2, ConstantInt *CI1,
                                        InstCombinerImpl &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);
IC.eraseInstFromFunction(*OrigAdd);

// The original icmp gets replaced with the overflow value.
return ExtractValueInst::Create(Call, 1, "sadd.overflow");
1338}

1340/// If we have:
1341///   icmp eq/ne (urem/srem %x, %y), 0
1342/// iff %y is a power-of-two, we can replace this with a bit test:
1343///   icmp eq/ne (and %x, (add %y, -1)), 0
1344Instruction *InstCombinerImpl::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);
1359}

1361/// Fold equality-comparison between zero and any (maybe truncated) right-shift
1362/// by one-less-than-bitwidth into a sign test on the original value.
1363Instruction *InstCombinerImpl::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));
1391}

1393// Handle  icmp pred X, 0
1394Instruction *InstCombinerImpl::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;
1428}

1430/// Fold icmp Pred X, C.
1431/// TODO: This code structure does not make sense. The saturating add fold
1432/// should be moved to some other helper and extended as noted below (it is also
1433/// possible that code has been made unnecessary - do we canonicalize IR to
1434/// overflow/saturating intrinsics or not?).
1435Instruction *InstCombinerImpl::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;

// icmp(phi(C1, C2, ...), C) -> phi(icmp(C1, C), icmp(C2, C), ...).
Constant *C = dyn_cast<Constant>(Op1);
if (!C)
  return nullptr;

if (auto *Phi = dyn_cast<PHINode>(Op0))
  if (all_of(Phi->operands(), [](Value *V) { return isa<Constant>(V); })) {
    Type *Ty = Cmp.getType();
    Builder.SetInsertPoint(Phi);
    PHINode *NewPhi =
        Builder.CreatePHI(Ty, Phi->getNumOperands());
    for (BasicBlock *Predecessor : predecessors(Phi->getParent())) {
      auto *Input =
          cast<Constant>(Phi->getIncomingValueForBlock(Predecessor));
      auto *BoolInput = ConstantExpr::getCompare(Pred, Input, C);
      NewPhi->addIncoming(BoolInput, Predecessor);
    }
    NewPhi->takeName(&Cmp);
    return replaceInstUsesWith(Cmp, NewPhi);
  }

return nullptr;
1478}

1480/// Canonicalize icmp instructions based on dominating conditions.
1481Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1495, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1495, __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;
1548}

1550/// Fold icmp (trunc X, Y), C.
1551Instruction *InstCombinerImpl::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;
1581}

1583/// Fold icmp (xor X, Y), C.
1584Instruction *InstCombinerImpl::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())
    return replaceOperand(Cmp, 0, X);

  // 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;
1650}

1652/// Fold icmp (and (sh X, Y), C2), C1.
1653Instruction *InstCombinerImpl::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))) {
  APInt NewAndCst, NewCmpCst;
  bool AnyCmpCstBitsShiftedOut;
  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()))
      return nullptr;

    NewCmpCst = C1.lshr(*C3);
    NewAndCst = C2.lshr(*C3);
    AnyCmpCstBitsShiftedOut = NewCmpCst.shl(*C3) != C1;
  } else if (ShiftOpcode == Instruction::LShr) {
    // 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.
    NewCmpCst = C1.shl(*C3);
    NewAndCst = C2.shl(*C3);
    AnyCmpCstBitsShiftedOut = NewCmpCst.lshr(*C3) != C1;
    if (Cmp.isSigned() && (NewAndCst.isNegative() || NewCmpCst.isNegative()))
      return nullptr;
  } else {
    // For an arithmetic shift, check that both constants don't use (in a
    // signed sense) the top bits being shifted out.
    assert(ShiftOpcode == Instruction::AShr && "Unknown shift opcode")((ShiftOpcode == Instruction::AShr && "Unknown shift opcode"
) ? static_cast<void> (0) : __assert_fail ("ShiftOpcode == Instruction::AShr && \"Unknown shift opcode\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 1696, __PRETTY_FUNCTION__));
    NewCmpCst = C1.shl(*C3);
    NewAndCst = C2.shl(*C3);
    AnyCmpCstBitsShiftedOut = NewCmpCst.ashr(*C3) != C1;
    if (NewAndCst.ashr(*C3) != C2)
      return nullptr;
  }

  if (AnyCmpCstBitsShiftedOut) {
    // 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 {
    Value *NewAnd = Builder.CreateAnd(
        Shift->getOperand(0), ConstantInt::get(And->getType(), NewAndCst));
    return new ICmpInst(Cmp.getPredicate(),
        NewAnd, ConstantInt::get(And->getType(), NewCmpCst));
  }
}

// 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);
  return replaceOperand(Cmp, 0, NewAnd);
}

return nullptr;
1736}

1738/// Fold icmp (and X, C2), C1.
1739Instruction *InstCombinerImpl::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());
      return replaceOperand(Cmp, 0, NewAnd);
    }
  }
}

return nullptr;
1844}

1846/// Fold icmp (and X, Y), C.
1847Instruction *InstCombinerImpl::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 (auto *AndVTy = dyn_cast<VectorType>(And->getType()))
      NTy = FixedVectorType::get(
          NTy, cast<FixedVectorType>(AndVTy)->getNumElements());
    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;
1899}

1901/// Fold icmp (or X, Y), C.
1902Instruction *InstCombinerImpl::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);
const APInt *MaskC;
if (match(OrOp1, m_APInt(MaskC)) && Cmp.isEquality()) {
  if (*MaskC == C && (C + 1).isPowerOf2()) {
    // 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)
    Pred = (Pred == CmpInst::ICMP_EQ) ? CmpInst::ICMP_ULE : CmpInst::ICMP_UGT;
    return new ICmpInst(Pred, OrOp0, OrOp1);
  }

  // More general: canonicalize 'equality with set bits mask' to
  // 'equality with clear bits mask'.
  // (X | MaskC) == C --> (X & ~MaskC) == C ^ MaskC
  // (X | MaskC) != C --> (X & ~MaskC) != C ^ MaskC
  if (Or->hasOneUse()) {
    Value *And = Builder.CreateAnd(OrOp0, ~(*MaskC));
    Constant *NewC = ConstantInt::get(Or->getType(), C ^ (*MaskC));
    return new ICmpInst(Pred, And, NewC);
  }
}

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;
1965}

1967/// Fold icmp (mul X, Y), C.
1968Instruction *InstCombinerImpl::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()));
}

// If the multiply does not wrap, try to divide the compare constant by the
// multiplication factor.
if (Cmp.isEquality() && !MulC->isNullValue()) {
  // (mul nsw X, MulC) == C --> X == C /s MulC
  if (Mul->hasNoSignedWrap() && C.srem(*MulC).isNullValue()) {
    Constant *NewC = ConstantInt::get(Mul->getType(), C.sdiv(*MulC));
    return new ICmpInst(Pred, Mul->getOperand(0), NewC);
  }
  // (mul nuw X, MulC) == C --> X == C /u MulC
  if (Mul->hasNoUnsignedWrap() && C.urem(*MulC).isNullValue()) {
    Constant *NewC = ConstantInt::get(Mul->getType(), C.udiv(*MulC));
    return new ICmpInst(Pred, Mul->getOperand(0), NewC);
  }
}

return nullptr;
2001}

2003/// Fold icmp (shl 1, Y), C.
2004static 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;
2063}

2065/// Fold icmp (shl X, Y), C.
2066Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2106, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2136, __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 (auto *ShVTy = dyn_cast<VectorType>(ShType))
    TruncTy = FixedVectorType::get(
        TruncTy, cast<FixedVectorType>(ShVTy)->getNumElements());
  Constant *NewC =
      ConstantInt::get(TruncTy, C.ashr(*ShiftAmt).trunc(TypeBits - Amt));
  return new ICmpInst(Pred, Builder.CreateTrunc(X, TruncTy), NewC);
}

return nullptr;
2204}

2206/// Fold icmp ({al}shr X, Y), C.
2207Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2281, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2281, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2281, __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;
2298}

2300Instruction *InstCombinerImpl::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));
2336}

2338/// Fold icmp (udiv X, Y), C.
2339Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2346, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2352, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2352, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2359, __PRETTY_FUNCTION__));
  return new ICmpInst(ICmpInst::ICMP_UGT, Y,
                      ConstantInt::get(Y->getType(), C2->udiv(C)));
}

return nullptr;
2365}

2367/// Fold icmp ({su}div X, Y), C.
2368Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2486);
  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;
2535}

2537/// Fold icmp (sub X, Y), C.
2538Instruction *InstCombinerImpl::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;
2597}

2599/// Fold icmp (add X, Y), C.
2600Instruction *InstCombinerImpl::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;
2664}

2666bool InstCombinerImpl::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 =
      InstCombiner::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2710, __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;
2717}

2719Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2723, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 2734, __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;
2768}

2770static 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()));

  // If this is a sign-bit test of a bitcast of a casted FP value, eliminate
  // the FP extend/truncate because that cast does not change the sign-bit.
  // This is true for all standard IEEE-754 types and the X86 80-bit type.
  // The sign-bit is always the most significant bit in those types.
  const APInt *C;
  bool TrueIfSigned;
  if (match(Op1, m_APInt(C)) && Bitcast->hasOneUse() &&
      InstCombiner::isSignBitCheck(Pred, *C, TrueIfSigned)) {
    if (match(BCSrcOp, m_FPExt(m_Value(X))) ||
        match(BCSrcOp, m_FPTrunc(m_Value(X)))) {
      // (bitcast (fpext/fptrunc X)) to iX) < 0 --> (bitcast X to iY) < 0
      // (bitcast (fpext/fptrunc X)) to iX) > -1 --> (bitcast X to iY) > -1
      Type *XType = X->getType();

      // We can't currently handle Power style floating point operations here.
      if (!(XType->isPPC_FP128Ty() || BCSrcOp->getType()->isPPC_FP128Ty())) {

        Type *NewType = Builder.getIntNTy(XType->getScalarSizeInBits());
        if (auto *XVTy = dyn_cast<VectorType>(XType))
          NewType = FixedVectorType::get(
              NewType, cast<FixedVectorType>(XVTy)->getNumElements());
        Value *NewBitcast = Builder.CreateBitCast(X, NewType);
        if (TrueIfSigned)
          return new ICmpInst(ICmpInst::ICMP_SLT, NewBitcast,
                              ConstantInt::getNullValue(NewType));
        else
          return new ICmpInst(ICmpInst::ICMP_SGT, NewBitcast,
                              ConstantInt::getAllOnesValue(NewType));
      }
    }
  }
}

// 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;
ArrayRef<int> Mask;
if (match(BCSrcOp, m_Shuffle(m_Value(Vec), m_Undef(), m_Mask(Mask)))) {
  // Check whether every element of Mask is the same constant
  if (is_splat(Mask)) {
    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 *Elem = Builder.getInt32(Mask[0]);
      Value *Extract = Builder.CreateExtractElement(Vec, Elem);
      Value *NewC = ConstantInt::get(EltTy, C->trunc(EltTy->getBitWidth()));
      return new ICmpInst(Pred, Extract, NewC);
    }
  }
}
return nullptr;
2892}

2894/// Try to fold integer comparisons with a constant operand: icmp Pred X, C
2895/// where X is some kind of instruction.
2896Instruction *InstCombinerImpl::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;
2977}

2979/// Fold an icmp equality instruction with binary operator LHS and constant RHS:
2980/// icmp eq/ne BO, C.
2981Instruction *InstCombinerImpl::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.
  if (Constant *BOC = dyn_cast<Constant>(BOp1)) {
    if (BO->hasOneUse())
      return new ICmpInst(Pred, BOp0, ConstantExpr::getSub(RHS, BOC));
  } 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()) {
    // Only check for constant LHS here, as constant RHS will be canonicalized
    // to add and use the fold above.
    if (Constant *BOC = dyn_cast<Constant>(BOp0)) {
      // Replace ((sub BOC, B) != C) with (B != BOC-C).
      return new ICmpInst(Pred, BOp1, ConstantExpr::getSub(BOC, RHS));
    } 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::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;
3083}

3085/// Fold an equality icmp with LLVM intrinsic and constant operand.
3086Instruction *InstCombinerImpl::foldICmpEqIntrinsicWithConstant(
  ICmpInst &Cmp, IntrinsicInst *II, const APInt &C) {
Type *Ty = II->getType();
unsigned BitWidth = C.getBitWidth();
switch (II->getIntrinsicID()) {
case Intrinsic::abs:
  // abs(A) == 0  ->  A == 0
  // abs(A) == INT_MIN  ->  A == INT_MIN
  if (C.isNullValue() || C.isMinSignedValue())
    return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),
                        ConstantInt::get(Ty, C));
  break;

case Intrinsic::bswap:
  // bswap(A) == C  ->  A == bswap(C)
  return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),
                      ConstantInt::get(Ty, C.byteSwap()));

case Intrinsic::ctlz:
case Intrinsic::cttz: {
  // ctz(A) == bitwidth(A)  ->  A == 0 and likewise for !=
  if (C == BitWidth)
    return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),
                        ConstantInt::getNullValue(Ty));

  // 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);
    return new ICmpInst(Cmp.getPredicate(),
        Builder.CreateAnd(II->getArgOperand(0), Mask1),
        ConstantInt::get(Ty, Mask2));
  }
  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)
    return new ICmpInst(Cmp.getPredicate(), II->getArgOperand(0),
        IsZero ? Constant::getNullValue(Ty) : Constant::getAllOnesValue(Ty));

  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 new ICmpInst(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 new ICmpInst(NewPred, II->getArgOperand(0), II->getArgOperand(1));
  }
  break;
}
default:
  break;
}

return nullptr;
3163}

3165/// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
3166Instruction *InstCombinerImpl::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;
3222}

3224/// Handle icmp with constant (but not simple integer constant) RHS.
3225Instruction *InstCombinerImpl::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;
3320}

3322/// Some comparisons can be simplified.
3323/// In this case, we are looking for comparisons that look like
3324/// a check for a lossy truncation.
3325/// Folds:
3326///   icmp SrcPred (x & Mask), x    to    icmp DstPred x, Mask
3327/// Where Mask is some pattern that produces all-ones in low bits:
3328///    (-1 >> y)
3329///    ((-1 << y) >> y)     <- non-canonical, has extra uses
3330///   ~(-1 << y)
3331///    ((1 << y) + (-1))    <- non-canonical, has extra uses
3332/// The Mask can be a constant, too.
3333/// For some predicates, the operands are commutative.
3334/// For others, x can only be on a specific side.
3335static 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_ULT:
  //  x & (-1 >> y) u< x    ->    x u> (-1 >> y)
  //  x u> x & (-1 >> y)    ->    x u> (-1 >> y)
  DstPred = ICmpInst::Predicate::ICMP_UGT;
  break;
case ICmpInst::Predicate::ICMP_UGE:
  //  x & (-1 >> y) u>= x    ->    x u<= (-1 >> y)
  //  x u<= x & (-1 >> y)    ->    x u<= (-1 >> y)
  DstPred = ICmpInst::Predicate::ICMP_ULE;
  break;
case ICmpInst::Predicate::ICMP_SLT:
  //  x & (-1 >> y) s< x    ->    x s> (-1 >> y)
  //  x s> x & (-1 >> y)    ->    x s> (-1 >> y)
  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)
  //  x s<= x & (-1 >> y)    ->    x s<= (-1 >> y)
  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_SGT:
case ICmpInst::Predicate::ICMP_SLE:
  return nullptr;
case ICmpInst::Predicate::ICMP_UGT:
case ICmpInst::Predicate::ICMP_ULE:
  llvm_unreachable("Instsimplify took care of commut. variant")::llvm::llvm_unreachable_internal("Instsimplify took care of commut. variant"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3393);
  break;
default:
  llvm_unreachable("All possible folds are handled.")::llvm::llvm_unreachable_internal("All possible folds are handled."
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3396);
}

// The mask value may be a vector constant that has undefined elements. But it
// may not be safe to propagate those undefs into the new compare, so replace
// those elements by copying an existing, defined, and safe scalar constant.
Type *OpTy = M->getType();
auto *VecC = dyn_cast<Constant>(M);
if (OpTy->isVectorTy() && VecC && VecC->containsUndefElement()) {
  auto *OpVTy = cast<FixedVectorType>(OpTy);
  Constant *SafeReplacementConstant = nullptr;
  for (unsigned i = 0, e = OpVTy->getNumElements(); i != e; ++i) {
    if (!isa<UndefValue>(VecC->getAggregateElement(i))) {
      SafeReplacementConstant = VecC->getAggregateElement(i);
      break;
    }
  }
  assert(SafeReplacementConstant && "Failed to find undef replacement")((SafeReplacementConstant && "Failed to find undef replacement"
) ? static_cast<void> (0) : __assert_fail ("SafeReplacementConstant && \"Failed to find undef replacement\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3413, __PRETTY_FUNCTION__));
  M = Constant::replaceUndefsWith(VecC, SafeReplacementConstant);
}

return Builder.CreateICmp(DstPred, X, M);
3418}

3420/// Some comparisons can be simplified.
3421/// In this case, we are looking for comparisons that look like
3422/// a check for a lossy signed truncation.
3423/// Folds:   (MaskedBits is a constant.)
3424///   ((%x << MaskedBits) a>> MaskedBits) SrcPred %x
3425/// Into:
3426///   (add %x, (1 << (KeptBits-1))) DstPred (1 << KeptBits)
3427/// Where  KeptBits = bitwidth(%x) - MaskedBits
3428static Value *
3429foldICmpWithTruncSignExtendedVal(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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3451, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3475, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3479, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3482, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3485, __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;
3493}

3495// Given pattern:
3496//   icmp eq/ne (and ((x shift Q), (y oppositeshift K))), 0
3497// we should move shifts to the same hand of 'and', i.e. rewrite as
3498//   icmp eq/ne (and (x shift (Q+K)), y), 0  iff (Q+K) u< bitwidth(x)
3499// We are only interested in opposite logical shifts here.
3500// One of the shifts can be truncated.
3501// If we can, we want to end up creating 'lshr' shift.
3502static Value *
3503foldShiftIntoShiftInAnotherHandOfAndInICmp(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();
Type *NarrowestTy = NarrowestShift->getType();
assert(NarrowestTy == I.getOperand(0)->getType() &&((NarrowestTy == I.getOperand(0)->getType() && "We did not look past any shifts while matching XShift though."
) ? static_cast<void> (0) : __assert_fail ("NarrowestTy == I.getOperand(0)->getType() && \"We did not look past any shifts while matching XShift though.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3532, __PRETTY_FUNCTION__))
       "We did not look past any shifts while matching XShift though.")((NarrowestTy == I.getOperand(0)->getType() && "We did not look past any shifts while matching XShift though."
) ? static_cast<void> (0) : __assert_fail ("NarrowestTy == I.getOperand(0)->getType() && \"We did not look past any shifts while matching XShift though.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3532, __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;

// As input, we have the following pattern:
//   icmp eq/ne (and ((x shift Q), (y oppositeshift K))), 0
// We want to rewrite that as:
//   icmp eq/ne (and (x shift (Q+K)), y), 0  iff (Q+K) u< bitwidth(x)
// While we know that originally (Q+K) would not overflow
// (because  2 * (N-1) u<= iN -1), we have looked past extensions of
// shift amounts. so it may now overflow in smaller bitwidth.
// To ensure that does not happen, we need to ensure that the total maximal
// shift amount is still representable in that smaller bit width.
unsigned MaximalPossibleTotalShiftAmount =
    (WidestTy->getScalarSizeInBits() - 1) +
    (NarrowestTy->getScalarSizeInBits() - 1);
APInt MaximalRepresentableShiftAmount =
    APInt::getAllOnesValue(XShAmt->getType()->getScalarSizeInBits());
if (MaximalRepresentableShiftAmount.ult(MaximalPossibleTotalShiftAmount))
  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));
3662}

3664/// Fold
3665///   (-1 u/ x) u< y
3666///   ((x * y) u/ x) != y
3667/// to
3668///   @llvm.umul.with.overflow(x, y) plus extraction of overflow bit
3669/// Note that the comparison is commutative, while inverted (u>=, ==) predicate
3670/// will mean that we are looking for the opposite answer.
3671Value *InstCombinerImpl::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;

  // 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");

// If we replaced the mul, erase it. Do this after all uses of Builder,
// as the mul is used as insertion point.
if (MulHadOtherUses)
  eraseInstFromFunction(*Mul);

return Res;
3731}

3733static Instruction *foldICmpXNegX(ICmpInst &I) {
CmpInst::Predicate Pred;
Value *X;
if (!match(&I, m_c_ICmp(Pred, m_NSWNeg(m_Value(X)), m_Deferred(X))))
  return nullptr;

if (ICmpInst::isSigned(Pred))
  Pred = ICmpInst::getSwappedPredicate(Pred);
else if (ICmpInst::isUnsigned(Pred))
  Pred = ICmpInst::getSignedPredicate(Pred);
// else for equality-comparisons just keep the predicate.

return ICmpInst::Create(Instruction::ICmp, Pred, X,
                        Constant::getNullValue(X->getType()), I.getName());
3747}

3749/// Try to fold icmp (binop), X or icmp X, (binop).
3750/// TODO: A large part of this logic is duplicated in InstSimplify's
3751/// simplifyICmpWithBinOp(). We should be able to share that and avoid the code
3752/// duplication.
3753Instruction *InstCombinerImpl::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;

if (Instruction *NewICmp = foldICmpXNegX(I))
  return NewICmp;

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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 3834, __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));
}

{
  // Try to remove shared constant multiplier from equality comparison:
  // X * C == Y * C (with no overflowing/aliasing) --> X == Y
  Value *X, *Y;
  const APInt *C;
  if (match(Op0, m_Mul(m_Value(X), m_APInt(C))) && *C != 0 &&
      match(Op1, m_Mul(m_Value(Y), m_SpecificInt(*C))) && I.isEquality())
    if (!C->countTrailingZeros() ||
        (BO0->hasNoSignedWrap() && BO1->hasNoSignedWrap()) ||
        (BO0->hasNoUnsignedWrap() && BO1->hasNoUnsignedWrap()))
    return new ICmpInst(Pred, X, Y);
}

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);
      }
    }
    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;
4131}

4133/// Fold icmp Pred min|max(X, Y), X.
4134static 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;
4218}

4220Instruction *InstCombinerImpl::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);
    return new ICmpInst(Pred, Op1, Constant::getNullValue(Op1->getType()));
  }
}

// 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;
4393}

4395static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4397, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4483, __PRETTY_FUNCTION__));
return new ICmpInst(CmpInst::ICMP_SLT, X, Constant::getNullValue(SrcTy));
4485}

4487/// Handle icmp (cast x), (cast or constant).
4488Instruction *InstCombinerImpl::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);
4529}

4531static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4534);
  case Instruction::Add:
  case Instruction::Sub:
    return match(RHS, m_Zero());
  case Instruction::Mul:
    return match(RHS, m_One());
}
4541}

4543OverflowResult
4544InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4549);
  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);
}
4566}

4568bool InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4610);
4611}

4613/// Recognize and process idiom involving test for multiplication
4614/// overflow.
4615///
4616/// The caller has matched a pattern of the form:
4617///   I = cmp u (mul(zext A, zext B), V
4618/// The function checks if this is a test for overflow and if so replaces
4619/// multiplication with call to 'mul.with.overflow' intrinsic.
4620///
4621/// \param I Compare instruction.
4622/// \param MulVal Result of 'mult' instruction.  It is one of the arguments of
4623///               the compare instruction.  Must be of integer type.
4624/// \param OtherVal The other argument of compare instruction.
4625/// \returns Instruction which must replace the compare instruction, NULL if no
4626///          replacement required.
4627static Instruction *processUMulZExtIdiom(ICmpInst &I, Value *MulVal,
                                       Value *OtherVal,
                                       InstCombinerImpl &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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4635, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4636, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4640, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4644, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4645, __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, 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.addToWorklist(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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4794, __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);
      Value *Zext = Builder.CreateZExt(ShortAnd, BO->getType());
      IC.replaceInstUsesWith(*BO, Zext);
    } else {
      llvm_unreachable("Unexpected Binary operation")::llvm::llvm_unreachable_internal("Unexpected Binary operation"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4802);
    }
    IC.addToWorklist(cast<Instruction>(U));
  }
}
if (isa<Instruction>(OtherVal))
  IC.addToWorklist(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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4832);
}
if (Inverse) {
  Value *Res = Builder.CreateExtractValue(Call, 1);
  return BinaryOperator::CreateNot(Res);
}

return ExtractValueInst::Create(Call, 1);
4840}

4842/// When performing a comparison against a constant, it is possible that not all
4843/// the bits in the LHS are demanded. This helper method computes the mask that
4844/// IS demanded.
4845static 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 (InstCombiner::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);
}
4872}

4874/// Check if the order of \p Op0 and \p Op1 as operands in an ICmpInst
4875/// should be swapped.
4876/// The decision is based on how many times these two operands are reused
4877/// as subtract operands and their positions in those instructions.
4878/// The rationale is that several architectures use the same instruction for
4879/// both subtract and cmp. Thus, it is better if the order of those operands
4880/// match.
4881/// \return true if Op0 and Op1 should be swapped.
4882static 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;
4898}

4900/// Check that one use is in the same block as the definition and all
4901/// other uses are in blocks dominated by a given block.
4902///
4903/// \param DI Definition
4904/// \param UI Use
4905/// \param DB Block that must dominate all uses of \p DI outside
4906///           the parent block
4907/// \return true when \p UI is the only use of \p DI in the parent block
4908/// and all other uses of \p DI are in blocks dominated by \p DB.
4909///
4910bool InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4913, __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;
4929}

4931/// Return true when the instruction sequence within a block is select-cmp-br.
4932static 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;
4943}

4945/// True when a select result is replaced by one of its operands
4946/// in select-icmp sequence. This will eventually result in the elimination
4947/// of the select.
4948///
4949/// \param SI    Select instruction
4950/// \param Icmp  Compare instruction
4951/// \param SIOpd Operand that replaces the select
4952///
4953/// Notes:
4954/// - The replacement is global and requires dominator information
4955/// - The caller is responsible for the actual replacement
4956///
4957/// Example:
4958///
4959/// entry:
4960///  %4 = select i1 %3, %C* %0, %C* null
4961///  %5 = icmp eq %C* %4, null
4962///  br i1 %5, label %9, label %7
4963///  ...
4964///  ; <label>:7                                       ; preds = %entry
4965///  %8 = getelementptr inbounds %C* %4, i64 0, i32 0
4966///  ...
4967///
4968/// can be transformed to
4969///
4970///  %5 = icmp eq %C* %0, null
4971///  %6 = select i1 %3, i1 %5, i1 true
4972///  br i1 %6, label %9, label %7
4973///  ...
4974///  ; <label>:7                                       ; preds = %entry
4975///  %8 = getelementptr inbounds %C* %0, i64 0, i32 0  // replace by %0!
4976///
4977/// Similar when the first operand of the select is a constant or/and
4978/// the compare is for not equal rather than equal.
4979///
4980/// NOTE: The function is only called when the select and compare constants
4981/// are equal, the optimization can work only for EQ predicates. This is not a
4982/// major restriction since a NE compare should be 'normalized' to an equal
4983/// compare, which usually happens in the combiner and test case
4984/// select-cmp-br.ll checks for it.
4985bool InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 4988, __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;
5009}

5011/// Try to fold the comparison based on range information we can get by checking
5012/// whether bits are known to be zero or one in the inputs.
5013Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5063);
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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5192, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5201, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5210, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5219, __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;
5237}

5239llvm::Optional<std::pair<CmpInst::Predicate, Constant *>>
5240InstCombiner::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5243, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5243, __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 (auto *FVTy = dyn_cast<FixedVectorType>(Type)) {
  unsigned NumElts = FVTy->getNumElements();
  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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5291, __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);
5302}

5304/// If we have an icmp le or icmp ge instruction with a constant operand, turn
5305/// it into the appropriate icmp lt or icmp gt instruction. This transform
5306/// allows them to be folded in visitICmpInst.
5307static ICmpInst *canonicalizeCmpWithConstant(ICmpInst &I) {
ICmpInst::Predicate Pred = I.getPredicate();
if (ICmpInst::isEquality(Pred) || !ICmpInst::isIntPredicate(Pred) ||
    InstCombiner::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 =
    InstCombiner::getFlippedStrictnessPredicateAndConstant(Pred, Op1C);
if (!FlippedStrictness)
  return nullptr;

return new ICmpInst(FlippedStrictness->first, Op0, FlippedStrictness->second);
5325}

5327/// If we have a comparison with a non-canonical predicate, if we can update
5328/// all the users, invert the predicate and adjust all the users.
5329CmpInst *InstCombinerImpl::canonicalizeICmpPredicate(CmpInst &I) {
// Is the predicate already canonical?
CmpInst::Predicate Pred = I.getPredicate();
if (InstCombiner::isCanonicalPredicate(Pred))
  return nullptr;

// Can all users be adjusted to predicate inversion?
if (!InstCombiner::canFreelyInvertAllUsersOf(&I, /*IgnoredUser=*/nullptr))
  return nullptr;

// Ok, we can canonicalize comparison!
// Let's first invert the comparison's predicate.
I.setPredicate(CmpInst::getInversePredicate(Pred));
I.setName(I.getName() + ".not");

// And now let's adjust every user.
for (User *U : I.users()) {
  switch (cast<Instruction>(U)->getOpcode()) {
  case Instruction::Select: {
    auto *SI = cast<SelectInst>(U);
    SI->swapValues();
    SI->swapProfMetadata();
    break;
  }
  case Instruction::Br:
    cast<BranchInst>(U)->swapSuccessors(); // swaps prof metadata too
    break;
  case Instruction::Xor:
    replaceInstUsesWith(cast<Instruction>(*U), &I);
    break;
  default:
    llvm_unreachable("Got unexpected user - out of sync with "::llvm::llvm_unreachable_internal("Got unexpected user - out of sync with "
 "canFreelyInvertAllUsersOf() ?", "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5361)
                     "canFreelyInvertAllUsersOf() ?")::llvm::llvm_unreachable_internal("Got unexpected user - out of sync with "
 "canFreelyInvertAllUsersOf() ?", "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5361);
  }
}

return &I;
5366}

5368/// Integer compare with boolean values can always be turned into bitwise ops.
5369static 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5372, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5384);
  }
} 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5393);
  }
}

switch (I.getPredicate()) {
default:
  llvm_unreachable("Invalid icmp instruction!")::llvm::llvm_unreachable_internal("Invalid icmp instruction!"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5399);
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);
}
5440}

5442// Transform pattern like:
5443//   (1 << Y) u<= X  or  ~(-1 << Y) u<  X  or  ((1 << Y)+(-1)) u<  X
5444//   (1 << Y) u>  X  or  ~(-1 << Y) u>= X  or  ((1 << Y)+(-1)) u>= X
5445// Into:
5446//   (X l>> Y) != 0
5447//   (X l>> Y) == 0
5448static Instruction *foldICmpWithHighBitMask(ICmpInst &Cmp,
                                          InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate Pred, NewPred;
Value *X, *Y;
if (match(&Cmp,
          m_c_ICmp(Pred, m_OneUse(m_Shl(m_One(), m_Value(Y))), m_Value(X)))) {
  switch (Pred) {
  case ICmpInst::ICMP_ULE:
    NewPred = ICmpInst::ICMP_NE;
    break;
  case ICmpInst::ICMP_UGT:
    NewPred = ICmpInst::ICMP_EQ;
    break;
  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,

  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");
Constant *Zero = Constant::getNullValue(NewX->getType());
return CmpInst::Create(Instruction::ICmp, NewPred, NewX, Zero);
5489}

5491static Instruction *foldVectorCmp(CmpInst &Cmp,
                                InstCombiner::BuilderTy &Builder) {
const CmpInst::Predicate Pred = Cmp.getPredicate();
Value *LHS = Cmp.getOperand(0), *RHS = Cmp.getOperand(1);
Value *V1, *V2;
ArrayRef<int> M;
if (!match(LHS, m_Shuffle(m_Value(V1), m_Undef(), m_Mask(M))))
  return nullptr;

// 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:
// cmp (shuffle V1, M), (shuffle V2, M) --> shuffle (cmp V1, V2), M
Type *V1Ty = V1->getType();
if (match(RHS, m_Shuffle(m_Value(V2), m_Undef(), m_SpecificMask(M))) &&
    V1Ty == V2->getType() && (LHS->hasOneUse() || RHS->hasOneUse())) {
  Value *NewCmp = Builder.CreateCmp(Pred, V1, V2);
  return new ShuffleVectorInst(NewCmp, UndefValue::get(NewCmp->getType()), M);
}

// Try to canonicalize compare with splatted operand and splat constant.
// TODO: We could generalize this for more than splats. See/use the code in
//       InstCombiner::foldVectorBinop().
Constant *C;
if (!LHS->hasOneUse() || !match(RHS, m_Constant(C)))
  return nullptr;

// Length-changing splats are ok, so adjust the constants as needed:
// cmp (shuffle V1, M), C --> shuffle (cmp V1, C'), M
Constant *ScalarC = C->getSplatValue(/* AllowUndefs */ true);
int MaskSplatIndex;
if (ScalarC && match(M, m_SplatOrUndefMask(MaskSplatIndex))) {
  // We allow undefs in matching, but this transform removes those for safety.
  // Demanded elements analysis should be able to recover some/all of that.
  C = ConstantVector::getSplat(cast<VectorType>(V1Ty)->getElementCount(),
                               ScalarC);
  SmallVector<int, 8> NewM(M.size(), MaskSplatIndex);
  Value *NewCmp = Builder.CreateCmp(Pred, V1, C);
  return new ShuffleVectorInst(NewCmp, UndefValue::get(NewCmp->getType()),
                               NewM);
}

return nullptr;
5533}

5535// extract(uadd.with.overflow(A, B), 0) ult A
5536//  -> extract(uadd.with.overflow(A, B), 1)
5537static 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);
5563}

5565Instruction *InstCombinerImpl::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 (Op0Cplxity0.1
'Op0Cplxity' is < 'Op1Cplxity'
1
'Op0Cplxity' is < 'Op1Cplxity'
 < Op1Cplxity ||
    (Op0Cplxity == Op1Cplxity && swapMayExposeCSEOpportunities(Op0, Op1))) {
  I.swapOperands();
  std::swap(Op0, Op1);
  Changed = true;
}

if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, Q))
1
Assuming 'V' is null→
2
←
Taking false branch→
  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())) {
3
←
Assuming the condition is false→
4
←
Taking false branch→
  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))
5
←
Assuming the condition is false→
6
←
Taking false branch→
  if (Instruction *Res = canonicalizeICmpBool(I, Builder))
    return Res;

if (Instruction *Res6.1
'Res' is null
1
'Res' is null
 = canonicalizeCmpWithConstant(I))
7
←
Taking false branch→
  return Res;

if (Instruction *Res7.1
'Res' is null
1
'Res' is null
 = canonicalizeICmpPredicate(I))
8
←
Taking false branch→
  return Res;

if (Instruction *Res8.1
'Res' is null
1
'Res' is null
 = foldICmpWithConstant(I))
9
←
Taking false branch→
  return Res;

if (Instruction *Res9.1
'Res' is null
1
'Res' is null
 = foldICmpWithDominatingICmp(I))
10
←
Taking false branch→
  return Res;

if (Instruction *Res = foldICmpBinOp(I, Q))
11
←
Assuming 'Res' is null→
12
←
Taking false branch→
  return Res;

if (Instruction *Res = foldICmpUsingKnownBits(I))
13
←
Assuming 'Res' is null→
14
←
Taking false branch→
  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())
15
←
Assuming the condition is false→
16
←
Taking false branch→
  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 *Res16.1
'Res' is null
1
'Res' is null
 = foldICmpWithZero(I))
17
←
Taking false branch→
  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))) {
18
←
Taking true branch→
  // For i32: x >u 2147483647 -> x <s 0  -> true if sign bit set
  if (Pred == ICmpInst::ICMP_UGT && C->isMaxSignedValue()) {
19
←
Assuming 'Pred' is not equal to ICMP_UGT→
    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()) {
20
←
Assuming 'Pred' is not equal to ICMP_ULT→
    Constant *AllOnes = Constant::getAllOnesValue(Op0->getType());
    return new ICmpInst(ICmpInst::ICMP_SGT, Op0, AllOnes);
  }
}

if (Instruction *Res20.1
'Res' is null
1
'Res' is null
 = foldICmpInstWithConstant(I))
21
←
Taking false branch→
  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 *New21.1
'New' is null
1
'New' is null
 = foldSignBitTest(I))
22
←
Taking false branch→
  return New;

if (Instruction *Res22.1
'Res' is null
1
'Res' is null
 = foldICmpInstWithConstantNotInt(I))
23
←
Taking false branch→
  return Res;

// If we can optimize a 'icmp GEP, P' or 'icmp P, GEP', do so now.
if (GEPOperator *GEP24.1
'GEP' is null
1
'GEP' is null
 = dyn_cast<GEPOperator>(Op0))
24
←
Assuming 'Op0' is not a 'GEPOperator'→
25
←
Taking false branch→
  if (Instruction *NI = foldGEPICmp(GEP, Op1, I.getPredicate(), I))
    return NI;
if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1))
26
←
Assuming 'GEP' is non-null→
27
←
Taking true branch→
  if (Instruction *NI = foldGEPICmp(GEP, Op0,
28
←
Calling 'InstCombinerImpl::foldGEPICmp'→
                         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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5688, __PRETTY_FUNCTION__));
  if (auto *Alloca = dyn_cast<AllocaInst>(getUnderlyingObject(Op0)))
    if (Instruction *New = foldAllocaCmp(I, Alloca, Op1))
      return New;
  if (auto *Alloca = dyn_cast<AllocaInst>(getUnderlyingObject(Op1)))
    if (Instruction *New = foldAllocaCmp(I, Alloca, Op0))
      return New;
}

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

// TODO: Hoist this above the min/max bailout.
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;
    // m_UAddWithOverflow can match patterns that do not include  an explicit
    // "add" instruction, so check the opcode of the matched op.
    if (AddI->getOpcode() == Instruction::Add &&
        OptimizeOverflowCheck(Instruction::Add, /*Signed*/ false, A, B, *AddI,
                              Result, Overflow)) {
      replaceInstUsesWith(*AddI, Result);
      eraseInstFromFunction(*AddI);
      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;
5800}

5802/// Fold fcmp ([us]itofp x, cst) if possible.
5803Instruction *InstCombinerImpl::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 != RHSRoundInt) {
      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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5834, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5871, __PRETTY_FUNCTION__));

ICmpInst::Predicate Pred;
switch (I.getPredicate()) {
default: llvm_unreachable("Unexpected predicate!")::llvm::llvm_unreachable_internal("Unexpected predicate!", "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5875);
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 < RHS) { // 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 < RHS) { // 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 > RHS) { // 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 UMin(RHS.getSemantics());
  UMin.convertFromAPInt(APInt::getMinValue(IntWidth), false,
                        APFloat::rmNearestTiesToEven);
  if (UMin > RHS) { // 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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 5978);
    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);
6040}

6042/// Fold (C / X) < 0.0 --> X < 0.0 if possible. Swap predicate if necessary.
6043static 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);
6087}

6089/// Optimize fabs(X) compared with zero.
6090static Instruction *foldFabsWithFcmpZero(FCmpInst &I, InstCombinerImpl &IC) {
Value *X;
if (!match(I.getOperand(0), m_Intrinsic<Intrinsic::fabs>(m_Value(X))) ||
    !match(I.getOperand(1), m_PosZeroFP()))
  return nullptr;

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

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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 6106);

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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 6126, __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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 6131, __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;
}
6150}

6152Instruction *InstCombinerImpl::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-12~++20200927111121+5811d723998/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp"
, 6171, __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))
    return replaceOperand(I, 0, ConstantFP::getNullValue(OpType));

  if (!match(Op1, m_PosZeroFP()) && isKnownNeverNaN(Op1, &TLI))
    return replaceOperand(I, 1, ConstantFP::getNullValue(OpType));
}

// 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()))
  return replaceOperand(I, 1, ConstantFP::getNullValue(OpType));

// 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, *this))
  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 < APFloat::getSmallestNormalized(FPSem)) || 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;
6306}

←

/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h

1//===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- 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 defines the SmallVector class.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_ADT_SMALLVECTOR_H
14#define LLVM_ADT_SMALLVECTOR_H

16#include "llvm/ADT/iterator_range.h"
17#include "llvm/Support/AlignOf.h"
18#include "llvm/Support/Compiler.h"
19#include "llvm/Support/ErrorHandling.h"
20#include "llvm/Support/MathExtras.h"
21#include "llvm/Support/MemAlloc.h"
22#include "llvm/Support/type_traits.h"
23#include <algorithm>
24#include <cassert>
25#include <cstddef>
26#include <cstdlib>
27#include <cstring>
28#include <initializer_list>
29#include <iterator>
30#include <limits>
31#include <memory>
32#include <new>
33#include <type_traits>
34#include <utility>

36namespace llvm {

38/// This is all the stuff common to all SmallVectors.
39///
40/// The template parameter specifies the type which should be used to hold the
41/// Size and Capacity of the SmallVector, so it can be adjusted.
42/// Using 32 bit size is desirable to shrink the size of the SmallVector.
43/// Using 64 bit size is desirable for cases like SmallVector<char>, where a
44/// 32 bit size would limit the vector to ~4GB. SmallVectors are used for
45/// buffering bitcode output - which can exceed 4GB.
46template <class Size_T> class SmallVectorBase {
47protected:
void *BeginX;
Size_T Size = 0, Capacity;

/// The maximum value of the Size_T used.
static constexpr size_t SizeTypeMax() {
  return std::numeric_limits<Size_T>::max();
}

SmallVectorBase() = delete;
SmallVectorBase(void *FirstEl, size_t TotalCapacity)
    : BeginX(FirstEl), Capacity(TotalCapacity) {}

/// This is an implementation of the grow() method which only works
/// on POD-like data types and is out of line to reduce code duplication.
/// This function will report a fatal error if it cannot increase capacity.
void grow_pod(void *FirstEl, size_t MinSize, size_t TSize);

/// Report that MinSize doesn't fit into this vector's size type. Throws
/// std::length_error or calls report_fatal_error.
LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) static void report_size_overflow(size_t MinSize);
/// Report that this vector is already at maximum capacity. Throws
/// std::length_error or calls report_fatal_error.
LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) static void report_at_maximum_capacity();

72public:
size_t size() const { return Size; }
size_t capacity() const { return Capacity; }

LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const { return !Size48.1
Field 'Size' is not equal to 0, which participates in a condition later
1
Field 'Size' is not equal to 0, which participates in a condition later
; }
44
←
Assuming field 'Size' is not equal to 0, which participates in a condition later→
45
←
Returning zero, which participates in a condition later→
49
←
Returning zero, which participates in a condition later→

/// Set the array size to \p N, which the current array must have enough
/// capacity for.
///
/// This does not construct or destroy any elements in the vector.
///
/// Clients can use this in conjunction with capacity() to write past the end
/// of the buffer when they know that more elements are available, and only
/// update the size later. This avoids the cost of value initializing elements
/// which will only be overwritten.
void set_size(size_t N) {
  assert(N <= capacity())((N <= capacity()) ? static_cast<void> (0) : __assert_fail
 ("N <= capacity()", "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 88, __PRETTY_FUNCTION__));
  Size = N;
}
91};

93template <class T>
94using SmallVectorSizeType =
  typename std::conditional<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t,
                            uint32_t>::type;

98/// Figure out the offset of the first element.
99template <class T, typename = void> struct SmallVectorAlignmentAndSize {
AlignedCharArrayUnion<SmallVectorBase<SmallVectorSizeType<T>>> Base;
AlignedCharArrayUnion<T> FirstEl;
102};

104/// This is the part of SmallVectorTemplateBase which does not depend on whether
105/// the type T is a POD. The extra dummy template argument is used by ArrayRef
106/// to avoid unnecessarily requiring T to be complete.
107template <typename T, typename = void>
108class SmallVectorTemplateCommon
  : public SmallVectorBase<SmallVectorSizeType<T>> {
using Base = SmallVectorBase<SmallVectorSizeType<T>>;

/// Find the address of the first element.  For this pointer math to be valid
/// with small-size of 0 for T with lots of alignment, it's important that
/// SmallVectorStorage is properly-aligned even for small-size of 0.
void *getFirstEl() const {
  return const_cast<void *>(reinterpret_cast<const void *>(
      reinterpret_cast<const char *>(this) +
      offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)__builtin_offsetof(SmallVectorAlignmentAndSize<T>, FirstEl
)));
}
// Space after 'FirstEl' is clobbered, do not add any instance vars after it.

122protected:
SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {}

void grow_pod(size_t MinSize, size_t TSize) {
  Base::grow_pod(getFirstEl(), MinSize, TSize);
}

/// Return true if this is a smallvector which has not had dynamic
/// memory allocated for it.
bool isSmall() const { return this->BeginX == getFirstEl(); }

/// Put this vector in a state of being small.
void resetToSmall() {
  this->BeginX = getFirstEl();
  this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
}

139public:
using size_type = size_t;
using difference_type = ptrdiff_t;
using value_type = T;
using iterator = T *;
using const_iterator = const T *;

using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = std::reverse_iterator<iterator>;

using reference = T &;
using const_reference = const T &;
using pointer = T *;
using const_pointer = const T *;

using Base::capacity;
using Base::empty;
using Base::size;

// forward iterator creation methods.
iterator begin() { return (iterator)this->BeginX; }
const_iterator begin() const { return (const_iterator)this->BeginX; }
iterator end() { return begin() + size(); }
const_iterator end() const { return begin() + size(); }

// reverse iterator creation methods.
reverse_iterator rbegin()            { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
reverse_iterator rend()              { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin());}

size_type size_in_bytes() const { return size() * sizeof(T); }
size_type max_size() const {
  return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T));
}

size_t capacity_in_bytes() const { return capacity() * sizeof(T); }

/// Return a pointer to the vector's buffer, even if empty().
pointer data() { return pointer(begin()); }
/// Return a pointer to the vector's buffer, even if empty().
const_pointer data() const { return const_pointer(begin()); }

reference operator[](size_type idx) {
  assert(idx < size())((idx < size()) ? static_cast<void> (0) : __assert_fail
 ("idx < size()", "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 183, __PRETTY_FUNCTION__));
  return begin()[idx];
}
const_reference operator[](size_type idx) const {
  assert(idx < size())((idx < size()) ? static_cast<void> (0) : __assert_fail
 ("idx < size()", "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 187, __PRETTY_FUNCTION__));
  return begin()[idx];
}

reference front() {
  assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 192, __PRETTY_FUNCTION__));
  return begin()[0];
}
const_reference front() const {
  assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 196, __PRETTY_FUNCTION__));
  return begin()[0];
}

reference back() {
  assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 201, __PRETTY_FUNCTION__));
  return end()[-1];
}
const_reference back() const {
  assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()"
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 205, __PRETTY_FUNCTION__));
  return end()[-1];
}
208};

210/// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put
211/// method implementations that are designed to work with non-trivial T's.
212///
213/// We approximate is_trivially_copyable with trivial move/copy construction and
214/// trivial destruction. While the standard doesn't specify that you're allowed
215/// copy these types with memcpy, there is no way for the type to observe this.
216/// This catches the important case of std::pair<POD, POD>, which is not
217/// trivially assignable.
218template <typename T, bool = (is_trivially_copy_constructible<T>::value) &&
                           (is_trivially_move_constructible<T>::value) &&
                           std::is_trivially_destructible<T>::value>
221class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
222protected:
SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}

static void destroy_range(T *S, T *E) {
  while (S != E) {
    --E;
    E->~T();
  }
}

/// Move the range [I, E) into the uninitialized memory starting with "Dest",
/// constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
  std::uninitialized_copy(std::make_move_iterator(I),
                          std::make_move_iterator(E), Dest);
}

/// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
/// constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
  std::uninitialized_copy(I, E, Dest);
}

/// Grow the allocated memory (without initializing new elements), doubling
/// the size of the allocated memory. Guarantees space for at least one more
/// element, or MinSize more elements if specified.
void grow(size_t MinSize = 0);

252public:
void push_back(const T &Elt) {
  if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity
()), false))
    this->grow();
  ::new ((void*) this->end()) T(Elt);
  this->set_size(this->size() + 1);
}

void push_back(T &&Elt) {
  if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity
()), false))
    this->grow();
  ::new ((void*) this->end()) T(::std::move(Elt));
  this->set_size(this->size() + 1);
}

void pop_back() {
  this->set_size(this->size() - 1);
  this->end()->~T();
}
271};

273// Define this out-of-line to dissuade the C++ compiler from inlining it.
274template <typename T, bool TriviallyCopyable>
275void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
// Ensure we can fit the new capacity.
// This is only going to be applicable when the capacity is 32 bit.
if (MinSize > this->SizeTypeMax())
  this->report_size_overflow(MinSize);

// Ensure we can meet the guarantee of space for at least one more element.
// The above check alone will not catch the case where grow is called with a
// default MinSize of 0, but the current capacity cannot be increased.
// This is only going to be applicable when the capacity is 32 bit.
if (this->capacity() == this->SizeTypeMax())
  this->report_at_maximum_capacity();

// Always grow, even from zero.
size_t NewCapacity = size_t(NextPowerOf2(this->capacity() + 2));
NewCapacity = std::min(std::max(NewCapacity, MinSize), this->SizeTypeMax());
T *NewElts = static_cast<T*>(llvm::safe_malloc(NewCapacity*sizeof(T)));

// Move the elements over.
this->uninitialized_move(this->begin(), this->end(), NewElts);

// Destroy the original elements.
destroy_range(this->begin(), this->end());

// If this wasn't grown from the inline copy, deallocate the old space.
if (!this->isSmall())
  free(this->begin());

this->BeginX = NewElts;
this->Capacity = NewCapacity;
305}

307/// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put
308/// method implementations that are designed to work with trivially copyable
309/// T's. This allows using memcpy in place of copy/move construction and
310/// skipping destruction.
311template <typename T>
312class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
313protected:
SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}

// No need to do a destroy loop for POD's.
static void destroy_range(T *, T *) {}

/// Move the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
  // Just do a copy.
  uninitialized_copy(I, E, Dest);
}

/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
  // Arbitrary iterator types; just use the basic implementation.
  std::uninitialized_copy(I, E, Dest);
}

/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template <typename T1, typename T2>
static void uninitialized_copy(
    T1 *I, T1 *E, T2 *Dest,
    std::enable_if_t<std::is_same<typename std::remove_const<T1>::type,
                                  T2>::value> * = nullptr) {
  // Use memcpy for PODs iterated by pointers (which includes SmallVector
  // iterators): std::uninitialized_copy optimizes to memmove, but we can
  // use memcpy here. Note that I and E are iterators and thus might be
  // invalid for memcpy if they are equal.
  if (I != E)
    memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
}

/// Double the size of the allocated memory, guaranteeing space for at
/// least one more element or MinSize if specified.
void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }

354public:
void push_back(const T &Elt) {
  if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity
()), false))
    this->grow();
  memcpy(reinterpret_cast<void *>(this->end()), &Elt, sizeof(T));
  this->set_size(this->size() + 1);
}

void pop_back() { this->set_size(this->size() - 1); }
363};

365/// This class consists of common code factored out of the SmallVector class to
366/// reduce code duplication based on the SmallVector 'N' template parameter.
367template <typename T>
368class SmallVectorImpl : public SmallVectorTemplateBase<T> {
using SuperClass = SmallVectorTemplateBase<T>;

371public:
using iterator = typename SuperClass::iterator;
using const_iterator = typename SuperClass::const_iterator;
using reference = typename SuperClass::reference;
using size_type = typename SuperClass::size_type;

377protected:
// Default ctor - Initialize to empty.
explicit SmallVectorImpl(unsigned N)
    : SmallVectorTemplateBase<T>(N) {}

382public:
SmallVectorImpl(const SmallVectorImpl &) = delete;

~SmallVectorImpl() {
  // Subclass has already destructed this vector's elements.
  // If this wasn't grown from the inline copy, deallocate the old space.
  if (!this->isSmall())
    free(this->begin());
}

void clear() {
  this->destroy_range(this->begin(), this->end());
  this->Size = 0;
}

void resize(size_type N) {
  if (N < this->size()) {
    this->destroy_range(this->begin()+N, this->end());
    this->set_size(N);
  } else if (N > this->size()) {
    if (this->capacity() < N)
      this->grow(N);
    for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
      new (&*I) T();
    this->set_size(N);
  }
}

void resize(size_type N, const T &NV) {
  if (N < this->size()) {
    this->destroy_range(this->begin()+N, this->end());
    this->set_size(N);
  } else if (N > this->size()) {
    if (this->capacity() < N)
      this->grow(N);
    std::uninitialized_fill(this->end(), this->begin()+N, NV);
    this->set_size(N);
  }
}

void reserve(size_type N) {
  if (this->capacity() < N)
    this->grow(N);
}

LLVM_NODISCARD[[clang::warn_unused_result]] T pop_back_val() {
  T Result = ::std::move(this->back());
  this->pop_back();
  return Result;
}

void swap(SmallVectorImpl &RHS);

/// Add the specified range to the end of the SmallVector.
template <typename in_iter,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<in_iter>::iterator_category,
              std::input_iterator_tag>::value>>
void append(in_iter in_start, in_iter in_end) {
  size_type NumInputs = std::distance(in_start, in_end);
  if (NumInputs > this->capacity() - this->size())
    this->grow(this->size()+NumInputs);

  this->uninitialized_copy(in_start, in_end, this->end());
  this->set_size(this->size() + NumInputs);
}

/// Append \p NumInputs copies of \p Elt to the end.
void append(size_type NumInputs, const T &Elt) {
  if (NumInputs > this->capacity() - this->size())
    this->grow(this->size()+NumInputs);

  std::uninitialized_fill_n(this->end(), NumInputs, Elt);
  this->set_size(this->size() + NumInputs);
}

void append(std::initializer_list<T> IL) {
  append(IL.begin(), IL.end());
}

// FIXME: Consider assigning over existing elements, rather than clearing &
// re-initializing them - for all assign(...) variants.

void assign(size_type NumElts, const T &Elt) {
  clear();
  if (this->capacity() < NumElts)
    this->grow(NumElts);
  this->set_size(NumElts);
  std::uninitialized_fill(this->begin(), this->end(), Elt);
}

template <typename in_iter,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<in_iter>::iterator_category,
              std::input_iterator_tag>::value>>
void assign(in_iter in_start, in_iter in_end) {
  clear();
  append(in_start, in_end);
}

void assign(std::initializer_list<T> IL) {
  clear();
  append(IL);
}

iterator erase(const_iterator CI) {
  // Just cast away constness because this is a non-const member function.
  iterator I = const_cast<iterator>(CI);

  assert(I >= this->begin() && "Iterator to erase is out of bounds.")((I >= this->begin() && "Iterator to erase is out of bounds."
) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Iterator to erase is out of bounds.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 491, __PRETTY_FUNCTION__));
  assert(I < this->end() && "Erasing at past-the-end iterator.")((I < this->end() && "Erasing at past-the-end iterator."
) ? static_cast<void> (0) : __assert_fail ("I < this->end() && \"Erasing at past-the-end iterator.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 492, __PRETTY_FUNCTION__));

  iterator N = I;
  // Shift all elts down one.
  std::move(I+1, this->end(), I);
  // Drop the last elt.
  this->pop_back();
  return(N);
}

iterator erase(const_iterator CS, const_iterator CE) {
  // Just cast away constness because this is a non-const member function.
  iterator S = const_cast<iterator>(CS);
  iterator E = const_cast<iterator>(CE);

  assert(S >= this->begin() && "Range to erase is out of bounds.")((S >= this->begin() && "Range to erase is out of bounds."
) ? static_cast<void> (0) : __assert_fail ("S >= this->begin() && \"Range to erase is out of bounds.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 507, __PRETTY_FUNCTION__));
  assert(S <= E && "Trying to erase invalid range.")((S <= E && "Trying to erase invalid range.") ? static_cast
<void> (0) : __assert_fail ("S <= E && \"Trying to erase invalid range.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 508, __PRETTY_FUNCTION__));
  assert(E <= this->end() && "Trying to erase past the end.")((E <= this->end() && "Trying to erase past the end."
) ? static_cast<void> (0) : __assert_fail ("E <= this->end() && \"Trying to erase past the end.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 509, __PRETTY_FUNCTION__));

  iterator N = S;
  // Shift all elts down.
  iterator I = std::move(E, this->end(), S);
  // Drop the last elts.
  this->destroy_range(I, this->end());
  this->set_size(I - this->begin());
  return(N);
}

iterator insert(iterator I, T &&Elt) {
  if (I == this->end()) {  // Important special case for empty vector.
    this->push_back(::std::move(Elt));
    return this->end()-1;
  }

  assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds."
) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 526, __PRETTY_FUNCTION__));
  assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector."
) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 527, __PRETTY_FUNCTION__));

  if (this->size() >= this->capacity()) {
    size_t EltNo = I-this->begin();
    this->grow();
    I = this->begin()+EltNo;
  }

  ::new ((void*) this->end()) T(::std::move(this->back()));
  // Push everything else over.
  std::move_backward(I, this->end()-1, this->end());
  this->set_size(this->size() + 1);

  // If we just moved the element we're inserting, be sure to update
  // the reference.
  T *EltPtr = &Elt;
  if (I <= EltPtr && EltPtr < this->end())
    ++EltPtr;

  *I = ::std::move(*EltPtr);
  return I;
}

iterator insert(iterator I, const T &Elt) {
  if (I == this->end()) {  // Important special case for empty vector.
    this->push_back(Elt);
    return this->end()-1;
  }

  assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds."
) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 556, __PRETTY_FUNCTION__));
  assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector."
) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 557, __PRETTY_FUNCTION__));

  if (this->size() >= this->capacity()) {
    size_t EltNo = I-this->begin();
    this->grow();
    I = this->begin()+EltNo;
  }
  ::new ((void*) this->end()) T(std::move(this->back()));
  // Push everything else over.
  std::move_backward(I, this->end()-1, this->end());
  this->set_size(this->size() + 1);

  // If we just moved the element we're inserting, be sure to update
  // the reference.
  const T *EltPtr = &Elt;
  if (I <= EltPtr && EltPtr < this->end())
    ++EltPtr;

  *I = *EltPtr;
  return I;
}

iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
  // Convert iterator to elt# to avoid invalidating iterator when we reserve()
  size_t InsertElt = I - this->begin();

  if (I == this->end()) {  // Important special case for empty vector.
    append(NumToInsert, Elt);
    return this->begin()+InsertElt;
  }

  assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds."
) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 588, __PRETTY_FUNCTION__));
  assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector."
) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 589, __PRETTY_FUNCTION__));

  // Ensure there is enough space.
  reserve(this->size() + NumToInsert);

  // Uninvalidate the iterator.
  I = this->begin()+InsertElt;

  // If there are more elements between the insertion point and the end of the
  // range than there are being inserted, we can use a simple approach to
  // insertion.  Since we already reserved space, we know that this won't
  // reallocate the vector.
  if (size_t(this->end()-I) >= NumToInsert) {
    T *OldEnd = this->end();
    append(std::move_iterator<iterator>(this->end() - NumToInsert),
           std::move_iterator<iterator>(this->end()));

    // Copy the existing elements that get replaced.
    std::move_backward(I, OldEnd-NumToInsert, OldEnd);

    std::fill_n(I, NumToInsert, Elt);
    return I;
  }

  // Otherwise, we're inserting more elements than exist already, and we're
  // not inserting at the end.

  // Move over the elements that we're about to overwrite.
  T *OldEnd = this->end();
  this->set_size(this->size() + NumToInsert);
  size_t NumOverwritten = OldEnd-I;
  this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);

  // Replace the overwritten part.
  std::fill_n(I, NumOverwritten, Elt);

  // Insert the non-overwritten middle part.
  std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
  return I;
}

template <typename ItTy,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<ItTy>::iterator_category,
              std::input_iterator_tag>::value>>
iterator insert(iterator I, ItTy From, ItTy To) {
  // Convert iterator to elt# to avoid invalidating iterator when we reserve()
  size_t InsertElt = I - this->begin();

  if (I == this->end()) {  // Important special case for empty vector.
    append(From, To);
    return this->begin()+InsertElt;
  }

  assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds."
) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 643, __PRETTY_FUNCTION__));
  assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector."
) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\""
, "/build/llvm-toolchain-snapshot-12~++20200927111121+5811d723998/llvm/include/llvm/ADT/SmallVector.h"
, 644, __PRETTY_FUNCTION__));

  size_t NumToInsert = std::distance(From, To);

  // Ensure there is enough space.
  reserve(this->size() + NumToInsert);

  // Uninvalidate the iterator.
  I = this->begin()+InsertElt;

  // If there are more elements between the insertion point and the end of the
  // range than there are being inserted, we can use a simple approach to
  // insertion.  Since we already reserved space, we know that this won't
  // reallocate the vector.
  if (size_t(this->end()-I) >= NumToInsert) {
    T *OldEnd = this->end();
    append(std::move_iterator<iterator>(this->end() - NumToInsert),
           std::move_iterator<iterator>(this->end()));

    // Copy the existing elements that get replaced.
    std::move_backward(I, OldEnd-NumToInsert, OldEnd);

    std::copy(From, To, I);
    return I;
  }

  // Otherwise, we're inserting more elements than exist already, and we're
  // not inserting at the end.

  // Move over the elements that we're about to overwrite.
  T *OldEnd = this->end();
  this->set_size(this->size() + NumToInsert);
  size_t NumOverwritten = OldEnd-I;
  this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);

  // Replace the overwritten part.
  for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
    *J = *From;
    ++J; ++From;
  }

  // Insert the non-overwritten middle part.
  this->uninitialized_copy(From, To, OldEnd);
  return I;
}

void insert(iterator I, std::initializer_list<T> IL) {
  insert(I, IL.begin(), IL.end());
}

template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) {
  if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity
()), false))
    this->grow();
  ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
  this->set_size(this->size() + 1);
  return this->back();
}

SmallVectorImpl &operator=(const SmallVectorImpl &RHS);

SmallVectorImpl &operator=(SmallVectorImpl &&RHS);

bool operator==(const SmallVectorImpl &RHS) const {
  if (this->size() != RHS.size()) return false;
  return std::equal(this->begin(), this->end(), RHS.begin());
}
bool operator!=(const SmallVectorImpl &RHS) const {
  return !(*this == RHS);
}

bool operator<(const SmallVectorImpl &RHS) const {
  return std::lexicographical_compare(this->begin(), this->end(),
                                      RHS.begin(), RHS.end());
}
718};

720template <typename T>
721void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
if (this == &RHS) return;

// We can only avoid copying elements if neither vector is small.
if (!this->isSmall() && !RHS.isSmall()) {
  std::swap(this->BeginX, RHS.BeginX);
  std::swap(this->Size, RHS.Size);
  std::swap(this->Capacity, RHS.Capacity);
  return;
}
if (RHS.size() > this->capacity())
  this->grow(RHS.size());
if (this->size() > RHS.capacity())
  RHS.grow(this->size());

// Swap the shared elements.
size_t NumShared = this->size();
if (NumShared > RHS.size()) NumShared = RHS.size();
for (size_type i = 0; i != NumShared; ++i)
  std::swap((*this)[i], RHS[i]);

// Copy over the extra elts.
if (this->size() > RHS.size()) {
  size_t EltDiff = this->size() - RHS.size();
  this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
  RHS.set_size(RHS.size() + EltDiff);
  this->destroy_range(this->begin()+NumShared, this->end());
  this->set_size(NumShared);
} else if (RHS.size() > this->size()) {
  size_t EltDiff = RHS.size() - this->size();
  this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
  this->set_size(this->size() + EltDiff);
  this->destroy_range(RHS.begin()+NumShared, RHS.end());
  RHS.set_size(NumShared);
}
756}

758template <typename T>
759SmallVectorImpl<T> &SmallVectorImpl<T>::
operator=(const SmallVectorImpl<T> &RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;

// If we already have sufficient space, assign the common elements, then
// destroy any excess.
size_t RHSSize = RHS.size();
size_t CurSize = this->size();
if (CurSize >= RHSSize) {
  // Assign common elements.
  iterator NewEnd;
  if (RHSSize)
    NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
  else
    NewEnd = this->begin();

  // Destroy excess elements.
  this->destroy_range(NewEnd, this->end());

  // Trim.
  this->set_size(RHSSize);
  return *this;
}

// If we have to grow to have enough elements, destroy the current elements.
// This allows us to avoid copying them during the grow.
// FIXME: don't do this if they're efficiently moveable.
if (this->capacity() < RHSSize) {
  // Destroy current elements.
  this->destroy_range(this->begin(), this->end());
  this->set_size(0);
  CurSize = 0;
  this->grow(RHSSize);
} else if (CurSize) {
  // Otherwise, use assignment for the already-constructed elements.
  std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
}

// Copy construct the new elements in place.
this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
                         this->begin()+CurSize);

// Set end.
this->set_size(RHSSize);
return *this;
805}

807template <typename T>
808SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;

// If the RHS isn't small, clear this vector and then steal its buffer.
if (!RHS.isSmall()) {
  this->destroy_range(this->begin(), this->end());
  if (!this->isSmall()) free(this->begin());
  this->BeginX = RHS.BeginX;
  this->Size = RHS.Size;
  this->Capacity = RHS.Capacity;
  RHS.resetToSmall();
  return *this;
}

// If we already have sufficient space, assign the common elements, then
// destroy any excess.
size_t RHSSize = RHS.size();
size_t CurSize = this->size();
if (CurSize >= RHSSize) {
  // Assign common elements.
  iterator NewEnd = this->begin();
  if (RHSSize)
    NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);

  // Destroy excess elements and trim the bounds.
  this->destroy_range(NewEnd, this->end());
  this->set_size(RHSSize);

  // Clear the RHS.
  RHS.clear();

  return *this;
}

// If we have to grow to have enough elements, destroy the current elements.
// This allows us to avoid copying them during the grow.
// FIXME: this may not actually make any sense if we can efficiently move
// elements.
if (this->capacity() < RHSSize) {
  // Destroy current elements.
  this->destroy_range(this->begin(), this->end());
  this->set_size(0);
  CurSize = 0;
  this->grow(RHSSize);
} else if (CurSize) {
  // Otherwise, use assignment for the already-constructed elements.
  std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
}

// Move-construct the new elements in place.
this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
                         this->begin()+CurSize);

// Set end.
this->set_size(RHSSize);

RHS.clear();
return *this;
867}

869/// Storage for the SmallVector elements.  This is specialized for the N=0 case
870/// to avoid allocating unnecessary storage.
871template <typename T, unsigned N>
872struct SmallVectorStorage {
AlignedCharArrayUnion<T> InlineElts[N];
874};

876/// We need the storage to be properly aligned even for small-size of 0 so that
877/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
878/// well-defined.
879template <typename T> struct alignas(alignof(T)) SmallVectorStorage<T, 0> {};

881/// This is a 'vector' (really, a variable-sized array), optimized
882/// for the case when the array is small.  It contains some number of elements
883/// in-place, which allows it to avoid heap allocation when the actual number of
884/// elements is below that threshold.  This allows normal "small" cases to be
885/// fast without losing generality for large inputs.
886///
887/// Note that this does not attempt to be exception safe.
888///
889template <typename T, unsigned N>
890class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector : public SmallVectorImpl<T>,
                                 SmallVectorStorage<T, N> {
892public:
SmallVector() : SmallVectorImpl<T>(N) {}

~SmallVector() {
  // Destroy the constructed elements in the vector.
  this->destroy_range(this->begin(), this->end());
}

explicit SmallVector(size_t Size, const T &Value = T())
  : SmallVectorImpl<T>(N) {
  this->assign(Size, Value);
}

template <typename ItTy,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<ItTy>::iterator_category,
              std::input_iterator_tag>::value>>
SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
  this->append(S, E);
}

template <typename RangeTy>
explicit SmallVector(const iterator_range<RangeTy> &R)
    : SmallVectorImpl<T>(N) {
  this->append(R.begin(), R.end());
}

SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
  this->assign(IL);
}

SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(RHS);
}

const SmallVector &operator=(const SmallVector &RHS) {
  SmallVectorImpl<T>::operator=(RHS);
  return *this;
}

SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(::std::move(RHS));
}

SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(::std::move(RHS));
}

const SmallVector &operator=(SmallVector &&RHS) {
  SmallVectorImpl<T>::operator=(::std::move(RHS));
  return *this;
}

const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
  SmallVectorImpl<T>::operator=(::std::move(RHS));
  return *this;
}

const SmallVector &operator=(std::initializer_list<T> IL) {
  this->assign(IL);
  return *this;
}
957};

959template <typename T, unsigned N>
960inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
return X.capacity_in_bytes();
962}

964/// Given a range of type R, iterate the entire range and return a
965/// SmallVector with elements of the vector.  This is useful, for example,
966/// when you want to iterate a range and then sort the results.
967template <unsigned Size, typename R>
968SmallVector<typename std::remove_const<typename std::remove_reference<
              decltype(*std::begin(std::declval<R &>()))>::type>::type,
          Size>
971to_vector(R &&Range) {
return {std::begin(Range), std::end(Range)};
973}

975} // end namespace llvm

977namespace std {

/// Implement std::swap in terms of SmallVector swap.
template<typename T>
inline void
swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
  LHS.swap(RHS);
}

/// Implement std::swap in terms of SmallVector swap.
template<typename T, unsigned N>
inline void
swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
  LHS.swap(RHS);
}

993} // end namespace std

995#endif // LLVM_ADT_SMALLVECTOR_H