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[InstCombine] Resolve TODO: nnan nsz X / -0.0 -> copysign(inf, X) #79766

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Merged
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Feb 7, 2024
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[InstCombine] Resolve TODO: nnan nsz X / -0.0 -> copysign(inf, X) #79766

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00c98e4
[InstCombine] pre-commit tests (NFC)
AZero13 Jan 28, 2024
0573290
[InstCombine] Resolve TODO: nnan nsz X / -0.0 -> copysign(inf, X)
AZero13 Jan 28, 2024
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6 changes: 4 additions & 2 deletions llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
View file
Original file line number Diff line number Diff line change
@@ -1598,9 +1598,11 @@ Instruction *InstCombinerImpl::foldFDivConstantDivisor(BinaryOperator &I) {
return BinaryOperator::CreateFDivFMF(X, NegC, &I);

// nnan X / +0.0 -> copysign(inf, X)
if (I.hasNoNaNs() && match(I.getOperand(1), m_Zero())) {
// nnan nsz X / -0.0 -> copysign(inf, X)
if (I.hasNoNaNs() &&
(match(I.getOperand(1), m_PosZeroFP()) ||
(I.hasNoSignedZeros() && match(I.getOperand(1), m_AnyZeroFP())))) {
IRBuilder<> B(&I);
// TODO: nnan nsz X / -0.0 -> copysign(inf, X)
CallInst *CopySign = B.CreateIntrinsic(
Intrinsic::copysign, {C->getType()},
{ConstantFP::getInfinity(I.getType()), I.getOperand(0)}, &I);
72 changes: 72 additions & 0 deletions llvm/test/Transforms/InstCombine/fdiv.ll
View file
Original file line number Diff line number Diff line change
@@ -992,3 +992,75 @@ define float @fdiv_nnan_neg_zero_f32(float %x) {
%fdiv = fdiv nnan float %x, -0.0
ret float %fdiv
}

define double @test_positive_zero_nsz(double %X) {
; CHECK-LABEL: @test_positive_zero_nsz(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz double @llvm.copysign.f64(double 0x7FF0000000000000, double [[X:%.*]])
; CHECK-NEXT: ret double [[TMP1]]
;
%1 = fdiv nnan nsz double %X, 0.0
ret double %1
}

define double @test_negative_zero_nsz(double %X) {
; CHECK-LABEL: @test_negative_zero_nsz(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz double @llvm.copysign.f64(double 0x7FF0000000000000, double [[X:%.*]])
; CHECK-NEXT: ret double [[TMP1]]
;
%1 = fdiv nnan nsz double %X, -0.0
ret double %1
}

define double @test_positive_zero(double %X) {
; CHECK-LABEL: @test_positive_zero(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan double @llvm.copysign.f64(double 0x7FF0000000000000, double [[X:%.*]])
; CHECK-NEXT: ret double [[TMP1]]
;
%1 = fdiv nnan double %X, 0.0
ret double %1
}

define double @test_negative_zero(double %X) {
; CHECK-LABEL: @test_negative_zero(
; CHECK-NEXT: [[TMP1:%.*]] = fdiv nnan double [[X:%.*]], -0.000000e+00
; CHECK-NEXT: ret double [[TMP1]]
;
%1 = fdiv nnan double %X, -0.0
ret double %1
}

define <2 x double> @test_positive_zero_vector_nsz(<2 x double> %X) {
; CHECK-LABEL: @test_positive_zero_vector_nsz(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz <2 x double> @llvm.copysign.v2f64(<2 x double> <double 0x7FF0000000000000, double 0x7FF0000000000000>, <2 x double> [[X:%.*]])
; CHECK-NEXT: ret <2 x double> [[TMP1]]
;
%1 = fdiv nnan nsz <2 x double> %X, <double 0.0, double 0.0>
ret <2 x double> %1
}

define <2 x double> @test_negative_zero_vector_nsz(<2 x double> %X) {
; CHECK-LABEL: @test_negative_zero_vector_nsz(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz <2 x double> @llvm.copysign.v2f64(<2 x double> <double 0x7FF0000000000000, double 0x7FF0000000000000>, <2 x double> [[X:%.*]])
; CHECK-NEXT: ret <2 x double> [[TMP1]]
;
%1 = fdiv nnan nsz <2 x double> %X, <double -0.0, double 0.0>
ret <2 x double> %1
}

define <2 x double> @test_positive_zero_vector(<2 x double> %X) {
; CHECK-LABEL: @test_positive_zero_vector(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan <2 x double> @llvm.copysign.v2f64(<2 x double> <double 0x7FF0000000000000, double 0x7FF0000000000000>, <2 x double> [[X:%.*]])
; CHECK-NEXT: ret <2 x double> [[TMP1]]
;
%1 = fdiv nnan <2 x double> %X, <double 0.0, double 0.0>
ret <2 x double> %1
}

define <2 x double> @test_negative_zero_vector(<2 x double> %X) {
; CHECK-LABEL: @test_negative_zero_vector(
; CHECK-NEXT: [[TMP1:%.*]] = fdiv nnan <2 x double> [[X:%.*]], <double -0.000000e+00, double 0.000000e+00>
; CHECK-NEXT: ret <2 x double> [[TMP1]]
;
%1 = fdiv nnan <2 x double> %X, <double -0.0, double 0.0>
ret <2 x double> %1
}