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[ConstantFolding] Fold sqrt poison -> poison #141821

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Merged
merged 8 commits into from
Jun 11, 2025
Merged

[ConstantFolding] Fold sqrt poison -> poison #141821

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de44594
Precommit tests
lukel97 May 28, 2025
bb2a84a
[InstSimplify] Fold poison/nnan/ninf on @llvm.sqrt
lukel97 May 28, 2025
e0f64a1
Handle poison in ConstantFolding
lukel97 May 28, 2025
9f64413
Merge branch 'main' of github.com:llvm/llvm-project into instsimplify…
lukel97 May 29, 2025
fd6e99e
Update test after 79ae407c95715f0be5a78260c3b135090f679637
lukel97 May 29, 2025
fbea3dc
Add test case for single poison element
lukel97 May 30, 2025
e1b1ea9
Merge branch 'main' into instsimplify/sqrt
lukel97 Jun 3, 2025
438025e
Merge branch 'main' into instsimplify/sqrt
lukel97 Jun 11, 2025
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7 changes: 6 additions & 1 deletion llvm/lib/Analysis/ConstantFolding.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2206,8 +2206,13 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,

if (isa<PoisonValue>(Operands[0])) {
// TODO: All of these operations should probably propagate poison.
if (IntrinsicID == Intrinsic::canonicalize)
switch (IntrinsicID) {
case Intrinsic::canonicalize:
case Intrinsic::sqrt:
return PoisonValue::get(Ty);
default:
break;
}
}

if (isa<UndefValue>(Operands[0])) {
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42 changes: 42 additions & 0 deletions llvm/test/Transforms/InstSimplify/fp-undef-poison.ll
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Expand Up @@ -293,3 +293,45 @@ define double @fmul_nnan_inf_op1(double %x) {
%r = fmul nnan double %x, 0xfff0000000000000
ret double %r
}

define float @sqrt_poison() {
; CHECK-LABEL: @sqrt_poison(
; CHECK-NEXT: ret float poison
;
%sqrt = call float @llvm.sqrt(float poison)
ret float %sqrt
}

define <2 x float> @sqrt_poison_fixed_vec() {
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@dtcxzyw dtcxzyw May 30, 2025

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Can you add a case with <float 1.0, float poison>?

; CHECK-LABEL: @sqrt_poison_fixed_vec(
; CHECK-NEXT: ret <2 x float> poison
;
%sqrt = call <2 x float> @llvm.sqrt(<2 x float> poison)
ret <2 x float> %sqrt
}

define <vscale x 2 x float> @sqrt_poison_scalable_vec() {
; CHECK-LABEL: @sqrt_poison_scalable_vec(
; CHECK-NEXT: ret <vscale x 2 x float> poison
;
%sqrt = call <vscale x 2 x float> @llvm.sqrt(<vscale x 2 x float> poison)
ret <vscale x 2 x float> %sqrt
}

define float @sqrt_nnan_nan() {
; CHECK-LABEL: @sqrt_nnan_nan(
; CHECK-NEXT: [[SQRT:%.*]] = call nnan float @llvm.sqrt.f32(float 0x7FF8000000000000)
; CHECK-NEXT: ret float [[SQRT]]
;
%sqrt = call nnan float @llvm.sqrt(float 0x7ff8000000000000)
ret float %sqrt
}

define float @sqrt_ninf_inf() {
; CHECK-LABEL: @sqrt_ninf_inf(
; CHECK-NEXT: [[SQRT:%.*]] = call ninf float @llvm.sqrt.f32(float 0xFFF0000000000000)
; CHECK-NEXT: ret float [[SQRT]]
;
%sqrt = call ninf float @llvm.sqrt(float 0xfff0000000000000)
ret float %sqrt
}