// (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);
- }
-
- Value *Rem;
- if (BO->getOpcode() == Instruction::UDiv)
- Rem = Builder->CreateURem(Op0BO, Op1BO);
- else
- Rem = Builder->CreateSRem(Op0BO, Op1BO);
- Rem->takeName(BO);
+ if (Div->isExact()) {
+ if (DivOp1 == Y)
+ return replaceInstUsesWith(I, X);
+ return BinaryOperator::CreateNeg(X);
+ }
- 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);
}
}