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[InstCombine] clean up foldICmpBinOpEqualityWithConstant / foldICmpIntrinsicWithConstant ; NFC 

1. Rename variables to be consistent with related/preceding code (may want to reorganize).
2. Fix comments/formatting.

llvm-svn: 281140
This commit is contained in:
Sanjay Patel 2016-09-10 15:33:39 +00:00
parent f58f68c891
commit 0a3d72bb93
1 changed files with 56 additions and 59 deletions
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115
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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@ -2230,27 +2230,29 @@ Instruction *InstCombiner::foldICmpInstWithConstant(ICmpInst &Cmp) {
return nullptr;
}
/// Simplify icmp_eq and icmp_ne instructions with binary operator LHS and
/// integer scalar or splat vector constant RHS.
Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
ICmpInst &ICI, BinaryOperator *BO, const APInt *RHSV) {
// FIXME: Some of these folds could work with arbitrary constants, but this
// match is limited to scalars and vector splat constants.
if (!ICI.isEquality())
/// Fold an icmp equality instruction with binary operator LHS and constant RHS:
/// icmp eq/ne BO, C.
Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
BinaryOperator *BO,
const APInt *C) {
// TODO: Some of these folds could work with arbitrary constants, but this
// function is limited to scalar and vector splat constants.
if (!Cmp.isEquality())
return nullptr;
Constant *RHS = cast<Constant>(ICI.getOperand(1));
bool isICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE;
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 (*RHSV == 0 && BO->hasOneUse()) {
if (*C == 0 && 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(ICI.getPredicate(), NewRem,
return new ICmpInst(Pred, NewRem,
Constant::getNullValue(BO->getType()));
}
}
@ -2261,19 +2263,19 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
if (match(BOp1, m_APInt(BOC))) {
if (BO->hasOneUse()) {
Constant *SubC = ConstantExpr::getSub(RHS, cast<Constant>(BOp1));
return new ICmpInst(ICI.getPredicate(), BOp0, SubC);
return new ICmpInst(Pred, BOp0, SubC);
}
} else if (*RHSV == 0) {
} else if (*C == 0) {
// 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(ICI.getPredicate(), BOp0, NegVal);
return new ICmpInst(Pred, BOp0, NegVal);
if (Value *NegVal = dyn_castNegVal(BOp0))
return new ICmpInst(ICI.getPredicate(), NegVal, BOp1);
return new ICmpInst(Pred, NegVal, BOp1);
if (BO->hasOneUse()) {
Value *Neg = Builder->CreateNeg(BOp1);
Neg->takeName(BO);
return new ICmpInst(ICI.getPredicate(), BOp0, Neg);
return new ICmpInst(Pred, BOp0, Neg);
}
}
break;
@ -2283,11 +2285,10 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
if (Constant *BOC = dyn_cast<Constant>(BOp1)) {
// For the xor case, we can xor two constants together, eliminating
// the explicit xor.
return new ICmpInst(ICI.getPredicate(), BOp0,
ConstantExpr::getXor(RHS, BOC));
} else if (*RHSV == 0) {
return new ICmpInst(Pred, BOp0, ConstantExpr::getXor(RHS, BOC));
} else if (*C == 0) {
// Replace ((xor A, B) != 0) with (A != B)
return new ICmpInst(ICI.getPredicate(), BOp0, BOp1);
return new ICmpInst(Pred, BOp0, BOp1);
}
}
break;
@ -2297,10 +2298,10 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
if (match(BOp0, m_APInt(BOC))) {
// Replace ((sub A, B) != C) with (B != A-C) if A & C are constants.
Constant *SubC = ConstantExpr::getSub(cast<Constant>(BOp0), RHS);
return new ICmpInst(ICI.getPredicate(), BOp1, SubC);
} else if (*RHSV == 0) {
return new ICmpInst(Pred, BOp1, SubC);
} else if (*C == 0) {
// Replace ((sub A, B) != 0) with (A != B)
return new ICmpInst(ICI.getPredicate(), BOp0, BOp1);
return new ICmpInst(Pred, BOp0, BOp1);
}
}
break;
@ -2312,7 +2313,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
// This removes the -1 constant.
Constant *NotBOC = ConstantExpr::getNot(cast<Constant>(BOp1));
Value *And = Builder->CreateAnd(BOp0, NotBOC);
return new ICmpInst(ICI.getPredicate(), And, NotBOC);
return new ICmpInst(Pred, And, NotBOC);
}
break;
}
@ -2320,7 +2321,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
const APInt *BOC;
if (match(BOp1, m_APInt(BOC))) {
// If we have ((X & C) == C), turn it into ((X & C) != 0).
if (RHSV == BOC && RHSV->isPowerOf2())
if (C == BOC && C->isPowerOf2())
return new ICmpInst(isICMP_NE ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE,
BO, Constant::getNullValue(RHS->getType()));
@ -2331,39 +2332,35 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
// Replace (and X, (1 << size(X)-1) != 0) with x s< 0
if (BOC->isSignBit()) {
Constant *Zero = Constant::getNullValue(BOp0->getType());
ICmpInst::Predicate Pred =
isICMP_NE ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_SGE;
return new ICmpInst(Pred, BOp0, Zero);
auto NewPred = isICMP_NE ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_SGE;
return new ICmpInst(NewPred, BOp0, Zero);
}
// ((X & ~7) == 0) --> X < 8
if (*RHSV == 0 && (~(*BOC) + 1).isPowerOf2()) {
if (*C == 0 && (~(*BOC) + 1).isPowerOf2()) {
Constant *NegBOC = ConstantExpr::getNeg(cast<Constant>(BOp1));
ICmpInst::Predicate Pred =
isICMP_NE ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_ULT;
return new ICmpInst(Pred, BOp0, NegBOC);
auto NewPred = isICMP_NE ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_ULT;
return new ICmpInst(NewPred, BOp0, NegBOC);
}
}
break;
}
case Instruction::Mul:
if (*RHSV == 0 && BO->hasNoSignedWrap()) {
if (*C == 0 && BO->hasNoSignedWrap()) {
const APInt *BOC;
if (match(BOp1, m_APInt(BOC)) && *BOC != 0) {
// The trivial case (mul X, 0) is handled by InstSimplify.
// General case : (mul X, C) != 0 iff X != 0
// (mul X, C) == 0 iff X == 0
return new ICmpInst(ICI.getPredicate(), BOp0,
Constant::getNullValue(RHS->getType()));
return new ICmpInst(Pred, BOp0, Constant::getNullValue(RHS->getType()));
}
}
break;
case Instruction::UDiv:
if (*RHSV == 0) {
if (*C == 0) {
// (icmp eq/ne (udiv A, B), 0) -> (icmp ugt/ule i32 B, A)
ICmpInst::Predicate Pred =
isICMP_NE ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_UGT;
return new ICmpInst(Pred, BOp1, BOp0);
auto NewPred = isICMP_NE ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_UGT;
return new ICmpInst(NewPred, BOp1, BOp0);
}
break;
default:
@ -2372,44 +2369,44 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(
return nullptr;
}
Instruction *InstCombiner::foldICmpIntrinsicWithConstant(ICmpInst &ICI,
const APInt *Op1C) {
IntrinsicInst *II = dyn_cast<IntrinsicInst>(ICI.getOperand(0));
if (!II || !ICI.isEquality())
/// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
Instruction *InstCombiner::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
const APInt *C) {
IntrinsicInst *II = dyn_cast<IntrinsicInst>(Cmp.getOperand(0));
if (!II || !Cmp.isEquality())
return nullptr;
// Handle icmp {eq|ne} <intrinsic>, intcst.
switch (II->getIntrinsicID()) {
case Intrinsic::bswap:
Worklist.Add(II);
ICI.setOperand(0, II->getArgOperand(0));
ICI.setOperand(1, Builder->getInt(Op1C->byteSwap()));
return &ICI;
Cmp.setOperand(0, II->getArgOperand(0));
Cmp.setOperand(1, Builder->getInt(C->byteSwap()));
return &Cmp;
case Intrinsic::ctlz:
case Intrinsic::cttz:
// ctz(A) == bitwidth(A) -> A == 0 and likewise for !=
if (*Op1C == Op1C->getBitWidth()) {
if (*C == C->getBitWidth()) {
Worklist.Add(II);
ICI.setOperand(0, II->getArgOperand(0));
ICI.setOperand(1, ConstantInt::getNullValue(II->getType()));
return &ICI;
Cmp.setOperand(0, II->getArgOperand(0));
Cmp.setOperand(1, ConstantInt::getNullValue(II->getType()));
return &Cmp;
}
break;
case Intrinsic::ctpop: {
// popcount(A) == 0 -> A == 0 and likewise for !=
// popcount(A) == bitwidth(A) -> A == -1 and likewise for !=
bool IsZero = *Op1C == 0;
if (IsZero || *Op1C == Op1C->getBitWidth()) {
bool IsZero = *C == 0;
if (IsZero || *C == C->getBitWidth()) {
Worklist.Add(II);
ICI.setOperand(0, II->getArgOperand(0));
auto *NewOp = IsZero
? ConstantInt::getNullValue(II->getType())
: ConstantInt::getAllOnesValue(II->getType());
ICI.setOperand(1, NewOp);
return &ICI;
}
Cmp.setOperand(0, II->getArgOperand(0));
auto *NewOp = IsZero ? Constant::getNullValue(II->getType())
: Constant::getAllOnesValue(II->getType());
Cmp.setOperand(1, NewOp);
return &Cmp;
}
break;
}
default:
break;
}