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[InstCombine] Preserve FMF for powi simplifications. 

Differential Revision: https://reviews.llvm.org/D95455
This commit is contained in:
Valery N Dmitriev 2021-01-26 11:05:16 -08:00
parent c8df2d1bde
commit 716b9dd0d8
2 changed files with 6 additions and 7 deletions
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9
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
View File

@ -886,15 +886,14 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
case Intrinsic::powi:
if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
// 0 and 1 are handled in instsimplify
// powi(x, -1) -> 1/x
if (Power->isMinusOne())
return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0),
II->getArgOperand(0));
return BinaryOperator::CreateFDivFMF(ConstantFP::get(CI.getType(), 1.0),
II->getArgOperand(0), II);
// powi(x, 2) -> x*x
if (Power->equalsInt(2))
return BinaryOperator::CreateFMul(II->getArgOperand(0),
II->getArgOperand(0));
return BinaryOperator::CreateFMulFMF(II->getArgOperand(0),
II->getArgOperand(0), II);
}
break;

4
llvm/test/Transforms/InstCombine/intrinsics.ll
View File

@ -22,9 +22,9 @@ declare double @llvm.nearbyint.f64(double %Val) nounwind readonly
define void @powi(double %V, double *%P) {
; CHECK-LABEL: @powi(
; CHECK-NEXT: [[A:%.*]] = fdiv double 1.000000e+00, [[V:%.*]]
; CHECK-NEXT: [[A:%.*]] = fdiv fast double 1.000000e+00, [[V:%.*]]
; CHECK-NEXT: store volatile double [[A]], double* [[P:%.*]], align 8
; CHECK-NEXT: [[D:%.*]] = fmul double [[V]], [[V]]
; CHECK-NEXT: [[D:%.*]] = fmul nnan double [[V]], [[V]]
; CHECK-NEXT: store volatile double [[D]], double* [[P]], align 8
; CHECK-NEXT: ret void
;