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[InstCombine] Use canIgnoreSignBitOfZero in spf->minmax fold #141914

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Merged
merged 2 commits into from
May 30, 2025
Merged

[InstCombine] Use canIgnoreSignBitOfZero in spf->minmax fold #141914

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9244e85
[InstCombine] use `canIgnoreSignBitOfZero` in `spf->minmax` fold
dtcxzyw May 29, 2025
5647e72
Remove unused file.
dtcxzyw May 29, 2025
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5 changes: 4 additions & 1 deletion llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3929,7 +3929,10 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {

// Canonicalize select of FP values where NaN and -0.0 are not valid as
// minnum/maxnum intrinsics.
if (SIFPOp->hasNoNaNs() && SIFPOp->hasNoSignedZeros()) {
if (SIFPOp->hasNoNaNs() &&
(SIFPOp->hasNoSignedZeros() ||
(SIFPOp->hasOneUse() &&
canIgnoreSignBitOfZero(*SIFPOp->use_begin())))) {
Value *X, *Y;
if (match(&SI, m_OrdOrUnordFMax(m_Value(X), m_Value(Y)))) {
Value *BinIntr =
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3 changes: 1 addition & 2 deletions llvm/test/Transforms/InstCombine/minmax-fp.ll
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Expand Up @@ -174,8 +174,7 @@ define i8 @t11(float %a, float %b) {
; Either operand could be NaN, but nnan modifier applied.
define i8 @t12(float %a, float %b) {
; CHECK-LABEL: @t12(
; CHECK-NEXT: [[DOTINV:%.*]] = fcmp nnan oge float [[B:%.*]], [[A:%.*]]
; CHECK-NEXT: [[DOTV:%.*]] = select nnan i1 [[DOTINV]], float [[A]], float [[B]]
; CHECK-NEXT: [[DOTV:%.*]] = call nnan float @llvm.minnum.f32(float [[B:%.*]], float [[A:%.*]])
; CHECK-NEXT: [[TMP1:%.*]] = fptosi float [[DOTV]] to i8
; CHECK-NEXT: ret i8 [[TMP1]]
;
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