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AMDGPU: Make rcp intrinsic propagate poison #130913

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Merged
merged 1 commit into from
Mar 13, 2025
Merged

AMDGPU: Make rcp intrinsic propagate poison #130913

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2 changes: 2 additions & 0 deletions llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -487,6 +487,8 @@ GCNTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
switch (IID) {
case Intrinsic::amdgcn_rcp: {
Value *Src = II.getArgOperand(0);
if (isa<PoisonValue>(Src))
return IC.replaceInstUsesWith(II, Src);

// TODO: Move to ConstantFolding/InstSimplify?
if (isa<UndefValue>(Src)) {
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8 changes: 8 additions & 0 deletions llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
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Expand Up @@ -8,6 +8,14 @@
declare float @llvm.amdgcn.rcp.f32(float) nounwind readnone
declare double @llvm.amdgcn.rcp.f64(double) nounwind readnone

define float @test_constant_fold_rcp_f32_poison() nounwind {
; CHECK-LABEL: @test_constant_fold_rcp_f32_poison(
; CHECK-NEXT: ret float poison
;
%val = call float @llvm.amdgcn.rcp.f32(float poison) nounwind readnone
ret float %val
}

define float @test_constant_fold_rcp_f32_undef() nounwind {
; CHECK-LABEL: @test_constant_fold_rcp_f32_undef(
; CHECK-NEXT: ret float 0x7FF8000000000000
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