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[InstCombine] improve readability; NFCI

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llvm-svn: 297755
This commit is contained in:
Sanjay Patel 2017-03-14 17:27:27 +00:00
parent 6c68ac572b
commit 0ee737e73e
1 changed files with 23 additions and 29 deletions
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52
lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
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@ -298,39 +298,33 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
// (X / Y) * Y = X - (X % Y)
// (X / Y) * -Y = (X % Y) - X
{
Value *Op1C = Op1;
BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0);
if (!BO ||
(BO->getOpcode() != Instruction::UDiv &&
BO->getOpcode() != Instruction::SDiv)) {
Op1C = Op0;
BO = dyn_cast<BinaryOperator>(Op1);
Value *Y = Op1;
BinaryOperator *Div = dyn_cast<BinaryOperator>(Op0);
if (!Div || (Div->getOpcode() != Instruction::UDiv &&
Div->getOpcode() != Instruction::SDiv)) {
Y = Op0;
Div = dyn_cast<BinaryOperator>(Op1);
}
Value *Neg = dyn_castNegVal(Op1C);
if (BO && BO->hasOneUse() &&
(BO->getOperand(1) == Op1C || BO->getOperand(1) == Neg) &&
(BO->getOpcode() == Instruction::UDiv ||
BO->getOpcode() == Instruction::SDiv)) {
Value *Op0BO = BO->getOperand(0), *Op1BO = BO->getOperand(1);
Value *Neg = dyn_castNegVal(Y);
if (Div && Div->hasOneUse() &&
(Div->getOperand(1) == Y || Div->getOperand(1) == Neg) &&
(Div->getOpcode() == Instruction::UDiv ||
Div->getOpcode() == Instruction::SDiv)) {
Value *X = Div->getOperand(0), *DivOp1 = Div->getOperand(1);
// If the division is exact, X % Y is zero, so we end up with X or -X.
if (PossiblyExactOperator *SDiv = dyn_cast<PossiblyExactOperator>(BO))
if (SDiv->isExact()) {
if (Op1BO == Op1C)
return replaceInstUsesWith(I, Op0BO);
return BinaryOperator::CreateNeg(Op0BO);
}
if (Div->isExact()) {
if (DivOp1 == Y)
return replaceInstUsesWith(I, X);
return BinaryOperator::CreateNeg(X);
}
Value *Rem;
if (BO->getOpcode() == Instruction::UDiv)
Rem = Builder->CreateURem(Op0BO, Op1BO);
else
Rem = Builder->CreateSRem(Op0BO, Op1BO);
Rem->takeName(BO);
if (Op1BO == Op1C)
return BinaryOperator::CreateSub(Op0BO, Rem);
return BinaryOperator::CreateSub(Rem, Op0BO);
auto RemOpc = Div->getOpcode() == Instruction::UDiv ? Instruction::URem
: Instruction::SRem;
Value *Rem = Builder->CreateBinOp(RemOpc, X, DivOp1);
if (DivOp1 == Y)
return BinaryOperator::CreateSub(X, Rem);
return BinaryOperator::CreateSub(Rem, X);
}
}