[llvm] [InstCombine] Ensure Safe Handling of Flags in foldFNegIntoConstant (PR #94148)
via llvm-commits
llvm-commits at lists.llvm.org
Sat Mar 15 01:27:06 PDT 2025
https://github.com/SahilPatidar updated https://github.com/llvm/llvm-project/pull/94148
>From e69cbb471bd99867075b0b8a47e725992de72d10 Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Fri, 31 May 2024 22:42:04 +0530
Subject: [PATCH 1/7] [InstCombine] Ensure Safe Handling of Flags in
foldFNegIntoConstant
---
.../InstCombine/InstCombineAddSub.cpp | 9 +++-
llvm/test/Transforms/InstCombine/fneg.ll | 41 +++++++++++++++++++
2 files changed, 49 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 658bbbc569766..986eda3c18fad 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2808,8 +2808,15 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// Fold negation into constant operand.
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
- if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
+ if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
+ if (match(C, m_AnyZeroFP()) && I.getFastMathFlags().noInfs()) {
+ return BinaryOperator::CreateFMulFMF(
+ X, NegC,
+ I.getFastMathFlags() &
+ cast<FPMathOperator>(I.getOperand(0))->getFastMathFlags());
+ }
return BinaryOperator::CreateFMulFMF(X, NegC, &I);
+ }
// -(X / C) --> X / (-C)
if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index 755beff9bf77a..57860abc858d8 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -1142,4 +1142,45 @@ define <vscale x 2 x double> @test_fneg_select_svec_3(<vscale x 2 x i1> %cond, <
ret <vscale x 2 x double> %2
}
+define float @test_fneg_ninf_mul_with_anyzero(float %a) {
+; CHECK-LABEL: @test_fneg_ninf_mul_with_anyzero(
+; CHECK-NEXT: [[F:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: ret float [[F]]
+;
+ %mul = fmul float %a, 0.0
+ %f = fneg ninf float %mul
+ ret float %f
+}
+
+define float @test_fsub_ninf_mul_with_anyzero(float %a) {
+; CHECK-LABEL: @test_fsub_ninf_mul_with_anyzero(
+; CHECK-NEXT: [[F2:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: ret float [[F2]]
+;
+ %f1 = fmul float %a, 0.000000
+ %f2 = fsub ninf float -0.000000, %f1
+ ret float %f2
+}
+
+define float @test_fneg_nnan_mul_with_anyzero(float %a) {
+; CHECK-LABEL: @test_fneg_nnan_mul_with_anyzero(
+; CHECK-NEXT: [[TMP1:%.*]] = fneg nnan float [[A:%.*]]
+; CHECK-NEXT: [[F2:%.*]] = call nnan float @llvm.copysign.f32(float 0.000000e+00, float [[TMP1]])
+; CHECK-NEXT: ret float [[F2]]
+;
+ %f1 = fmul float %a, 0.000000
+ %f2 = fneg nnan float %f1
+ ret float %f2
+}
+
+define float @test_fneg_nsz_mul_with_anyzero(float %a) {
+; CHECK-LABEL: @test_fneg_nsz_mul_with_anyzero(
+; CHECK-NEXT: [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: ret float [[F2]]
+;
+ %f1 = fmul float %a, 0.000000
+ %f2 = fneg nsz float %f1
+ ret float %f2
+}
+
!0 = !{}
>From 997368330face295c9da5d0d7d2c074a306f0efe Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Fri, 7 Jun 2024 16:16:44 +0530
Subject: [PATCH 2/7] Fixes logic and update tests
---
.../InstCombine/InstCombineAddSub.cpp | 24 +++++++++--
llvm/test/Transforms/InstCombine/fneg.ll | 42 +++++++++++++++++++
2 files changed, 62 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 986eda3c18fad..86a03448a006c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2792,6 +2792,22 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
return TryToNarrowDeduceFlags();
}
+static FastMathFlags getCorrectFMFForFNeg(FastMathFlags F1, FastMathFlags F2) {
+
+ FastMathFlags NF1 = F1 & F2;
+ FastMathFlags NF2 = F1 | F2;
+ if (NF2.noNaNs())
+ return F2;
+
+ if (NF1.any() || (F1.none() && F2.none()))
+ return NF1;
+
+ if (F1.all() || F2.all())
+ return F2;
+
+ return NF1;
+}
+
/// This eliminates floating-point negation in either 'fneg(X)' or
/// 'fsub(-0.0, X)' form by combining into a constant operand.
static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
@@ -2809,11 +2825,11 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
- if (match(C, m_AnyZeroFP()) && I.getFastMathFlags().noInfs()) {
- return BinaryOperator::CreateFMulFMF(
+ FastMathFlags FMF = cast<FPMathOperator>(I.getOperand(0))->getFastMathFlags();
+ if (I.getFastMathFlags().noInfs()) {
+ return BinaryOperator::CreateFMulFMF(
X, NegC,
- I.getFastMathFlags() &
- cast<FPMathOperator>(I.getOperand(0))->getFastMathFlags());
+ getCorrectFMFForFNeg(I.getFastMathFlags(), FMF));
}
return BinaryOperator::CreateFMulFMF(X, NegC, &I);
}
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index 57860abc858d8..54753d5b85da6 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -1183,4 +1183,46 @@ define float @test_fneg_nsz_mul_with_anyzero(float %a) {
ret float %f2
}
+define float @test_fneg_ninf_mul_nnan_with_const(float %a) {
+; CHECK-LABEL: @test_fneg_ninf_mul_nnan_with_const(
+; CHECK-NEXT: [[TMP1:%.*]] = fneg float [[A:%.*]]
+; CHECK-NEXT: [[F2:%.*]] = call float @llvm.copysign.f32(float 0.000000e+00, float [[TMP1]])
+; CHECK-NEXT: ret float [[F2]]
+;
+ %f1 = fmul nnan float %a, 0.000000
+ %f2 = fneg ninf float %f1
+ ret float %f2
+}
+
+define float @test_fneg_ninf_mul_nsz_with_const(float %a) {
+; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_const(
+; CHECK-NEXT: [[F2:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: ret float [[F2]]
+;
+ %f1 = fmul nsz float %a, 0.000000
+ %f2 = fneg ninf float %f1
+ ret float %f2
+}
+
+define <2 x float> @test_fneg_ninf_mul_nnan_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_ninf_mul_nnan_with_vec_const(
+; CHECK-NEXT: [[F2:%.*]] = fmul nnan <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul nnan <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_vec_const(
+; CHECK-NEXT: [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul nsz <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+
!0 = !{}
>From 12ab9997e748beab45f33a6fb82994f6e8a08b26 Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Tue, 9 Jul 2024 11:17:01 +0530
Subject: [PATCH 3/7] Propagate the `FNegOp` FMF flag instead of `I`.
---
.../InstCombine/InstCombineAddSub.cpp | 27 ++---------------
llvm/test/Transforms/InstCombine/fneg.ll | 30 ++++++++++++-------
llvm/test/Transforms/InstCombine/fsub.ll | 2 +-
3 files changed, 22 insertions(+), 37 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 86a03448a006c..eb4bc85f75c48 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2792,22 +2792,6 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
return TryToNarrowDeduceFlags();
}
-static FastMathFlags getCorrectFMFForFNeg(FastMathFlags F1, FastMathFlags F2) {
-
- FastMathFlags NF1 = F1 & F2;
- FastMathFlags NF2 = F1 | F2;
- if (NF2.noNaNs())
- return F2;
-
- if (NF1.any() || (F1.none() && F2.none()))
- return NF1;
-
- if (F1.all() || F2.all())
- return F2;
-
- return NF1;
-}
-
/// This eliminates floating-point negation in either 'fneg(X)' or
/// 'fsub(-0.0, X)' form by combining into a constant operand.
static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
@@ -2824,15 +2808,8 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// Fold negation into constant operand.
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
- if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
- FastMathFlags FMF = cast<FPMathOperator>(I.getOperand(0))->getFastMathFlags();
- if (I.getFastMathFlags().noInfs()) {
- return BinaryOperator::CreateFMulFMF(
- X, NegC,
- getCorrectFMFForFNeg(I.getFastMathFlags(), FMF));
- }
- return BinaryOperator::CreateFMulFMF(X, NegC, &I);
- }
+ if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
+ return BinaryOperator::CreateFMulFMF(X, NegC, FNegOp);
// -(X / C) --> X / (-C)
if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index 54753d5b85da6..6049b6b82de13 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -42,7 +42,7 @@ define float @fmul_fneg(float %x) {
define float @fmul_fsub_fmf(float %x) {
; CHECK-LABEL: @fmul_fsub_fmf(
-; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%m = fmul float %x, 42.0
@@ -52,7 +52,7 @@ define float @fmul_fsub_fmf(float %x) {
define float @fmul_fneg_fmf(float %x) {
; CHECK-LABEL: @fmul_fneg_fmf(
-; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%m = fmul float %x, 42.0
@@ -1154,31 +1154,30 @@ define float @test_fneg_ninf_mul_with_anyzero(float %a) {
define float @test_fsub_ninf_mul_with_anyzero(float %a) {
; CHECK-LABEL: @test_fsub_ninf_mul_with_anyzero(
-; CHECK-NEXT: [[F2:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
; CHECK-NEXT: ret float [[F2]]
;
- %f1 = fmul float %a, 0.000000
+ %f1 = fmul nsz float %a, 0.000000
%f2 = fsub ninf float -0.000000, %f1
ret float %f2
}
define float @test_fneg_nnan_mul_with_anyzero(float %a) {
; CHECK-LABEL: @test_fneg_nnan_mul_with_anyzero(
-; CHECK-NEXT: [[TMP1:%.*]] = fneg nnan float [[A:%.*]]
-; CHECK-NEXT: [[F2:%.*]] = call nnan float @llvm.copysign.f32(float 0.000000e+00, float [[TMP1]])
+; CHECK-NEXT: [[F2:%.*]] = fmul ninf float [[A:%.*]], -0.000000e+00
; CHECK-NEXT: ret float [[F2]]
;
- %f1 = fmul float %a, 0.000000
+ %f1 = fmul ninf float %a, 0.000000
%f2 = fneg nnan float %f1
ret float %f2
}
define float @test_fneg_nsz_mul_with_anyzero(float %a) {
; CHECK-LABEL: @test_fneg_nsz_mul_with_anyzero(
-; CHECK-NEXT: [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: [[F2:%.*]] = fmul ninf float [[A:%.*]], -0.000000e+00
; CHECK-NEXT: ret float [[F2]]
;
- %f1 = fmul float %a, 0.000000
+ %f1 = fmul ninf float %a, 0.000000
%f2 = fneg nsz float %f1
ret float %f2
}
@@ -1196,7 +1195,7 @@ define float @test_fneg_ninf_mul_nnan_with_const(float %a) {
define float @test_fneg_ninf_mul_nsz_with_const(float %a) {
; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_const(
-; CHECK-NEXT: [[F2:%.*]] = fmul float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
; CHECK-NEXT: ret float [[F2]]
;
%f1 = fmul nsz float %a, 0.000000
@@ -1216,7 +1215,7 @@ define <2 x float> @test_fneg_ninf_mul_nnan_with_vec_const(<2 x float> %a) {
define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_vec_const(
-; CHECK-NEXT: [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: [[F2:%.*]] = fmul nsz <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
; CHECK-NEXT: ret <2 x float> [[F2]]
;
%f1 = fmul nsz <2 x float> %a, <float 0.000000, float -0.000000>
@@ -1224,5 +1223,14 @@ define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
ret <2 x float> %f2
}
+define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_nnan_ninf_mul_with_vec_const(
+; CHECK-NEXT: [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg nnan ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
!0 = !{}
diff --git a/llvm/test/Transforms/InstCombine/fsub.ll b/llvm/test/Transforms/InstCombine/fsub.ll
index cffc63405ddcb..b43ea2a13b99d 100644
--- a/llvm/test/Transforms/InstCombine/fsub.ll
+++ b/llvm/test/Transforms/InstCombine/fsub.ll
@@ -98,7 +98,7 @@ define float @sub_sub_nsz(float %x, float %y, float %z) {
define float @sub_add_neg_x(float %x, float %y) {
; CHECK-LABEL: @sub_add_neg_x(
-; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -5.000000e+00
+; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -5.000000e+00
; CHECK-NEXT: ret float [[R]]
;
%mul = fmul float %x, 5.000000e+00
>From c47dc0a7c6c4e27bb1662cec525f9cea4f8f47b8 Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Fri, 23 Aug 2024 13:41:59 +0530
Subject: [PATCH 4/7] Update Flag Propagation Logic
---
llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 8 ++++++--
llvm/test/Transforms/InstCombine/fneg.ll | 11 ++++++-----
llvm/test/Transforms/InstCombine/fsub.ll | 2 +-
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index eb4bc85f75c48..2263d6fed9e58 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2808,8 +2808,12 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// Fold negation into constant operand.
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
- if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
- return BinaryOperator::CreateFMulFMF(X, NegC, FNegOp);
+ if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
+ FastMathFlags Flag = I.getFastMathFlags() | FNegOp->getFastMathFlags();
+ Flag.setNoInfs(I.getFastMathFlags().noInfs() &&
+ FNegOp->getFastMathFlags().noInfs());
+ return BinaryOperator::CreateFMulFMF(X, NegC, Flag);
+ }
// -(X / C) --> X / (-C)
if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL))
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index 6049b6b82de13..3be00fa82cf8d 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -42,7 +42,7 @@ define float @fmul_fneg(float %x) {
define float @fmul_fsub_fmf(float %x) {
; CHECK-LABEL: @fmul_fsub_fmf(
-; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%m = fmul float %x, 42.0
@@ -52,7 +52,7 @@ define float @fmul_fsub_fmf(float %x) {
define float @fmul_fneg_fmf(float %x) {
; CHECK-LABEL: @fmul_fneg_fmf(
-; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%m = fmul float %x, 42.0
@@ -1164,7 +1164,8 @@ define float @test_fsub_ninf_mul_with_anyzero(float %a) {
define float @test_fneg_nnan_mul_with_anyzero(float %a) {
; CHECK-LABEL: @test_fneg_nnan_mul_with_anyzero(
-; CHECK-NEXT: [[F2:%.*]] = fmul ninf float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: [[TMP1:%.*]] = fneg nnan float [[A:%.*]]
+; CHECK-NEXT: [[F2:%.*]] = call nnan float @llvm.copysign.f32(float 0.000000e+00, float [[TMP1]])
; CHECK-NEXT: ret float [[F2]]
;
%f1 = fmul ninf float %a, 0.000000
@@ -1174,7 +1175,7 @@ define float @test_fneg_nnan_mul_with_anyzero(float %a) {
define float @test_fneg_nsz_mul_with_anyzero(float %a) {
; CHECK-LABEL: @test_fneg_nsz_mul_with_anyzero(
-; CHECK-NEXT: [[F2:%.*]] = fmul ninf float [[A:%.*]], -0.000000e+00
+; CHECK-NEXT: [[F2:%.*]] = fmul nsz float [[A:%.*]], -0.000000e+00
; CHECK-NEXT: ret float [[F2]]
;
%f1 = fmul ninf float %a, 0.000000
@@ -1225,7 +1226,7 @@ define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
; CHECK-LABEL: @test_fneg_nnan_ninf_mul_with_vec_const(
-; CHECK-NEXT: [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: [[F2:%.*]] = fmul nnan <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
; CHECK-NEXT: ret <2 x float> [[F2]]
;
%f1 = fmul <2 x float> %a, <float 0.000000, float -0.000000>
diff --git a/llvm/test/Transforms/InstCombine/fsub.ll b/llvm/test/Transforms/InstCombine/fsub.ll
index b43ea2a13b99d..cffc63405ddcb 100644
--- a/llvm/test/Transforms/InstCombine/fsub.ll
+++ b/llvm/test/Transforms/InstCombine/fsub.ll
@@ -98,7 +98,7 @@ define float @sub_sub_nsz(float %x, float %y, float %z) {
define float @sub_add_neg_x(float %x, float %y) {
; CHECK-LABEL: @sub_add_neg_x(
-; CHECK-NEXT: [[R:%.*]] = fmul float [[X:%.*]], -5.000000e+00
+; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -5.000000e+00
; CHECK-NEXT: ret float [[R]]
;
%mul = fmul float %x, 5.000000e+00
>From 0aff15a01874c9cd4ff81b071085613302e3328c Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Fri, 27 Sep 2024 17:01:51 +0530
Subject: [PATCH 5/7] Refactor logic and add additional tests
---
llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 7 ++++---
llvm/test/Transforms/InstCombine/fneg.ll | 10 ++++++++++
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 2263d6fed9e58..1ca2ee4674af2 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2809,9 +2809,10 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
- FastMathFlags Flag = I.getFastMathFlags() | FNegOp->getFastMathFlags();
- Flag.setNoInfs(I.getFastMathFlags().noInfs() &&
- FNegOp->getFastMathFlags().noInfs());
+ FastMathFlags FMF = I.getFastMathFlags();
+ FastMathFlags OpFMF = FNegOp->getFastMathFlags();
+ FastMathFlags Flag = FMF | OpFMF;
+ Flag.setNoInfs(FMF.noInfs() && OpFMF.noInfs());
return BinaryOperator::CreateFMulFMF(X, NegC, Flag);
}
// -(X / C) --> X / (-C)
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index 3be00fa82cf8d..968266f674227 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -1234,4 +1234,14 @@ define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
ret <2 x float> %f2
}
+define <2 x float> @test_fneg_nnan_ninf_mul_ninf_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_nnan_ninf_mul_ninf_with_vec_const(
+; CHECK-NEXT: [[F2:%.*]] = fmul nnan ninf <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul ninf <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg nnan ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
!0 = !{}
>From def94640efb8c1e74079930fc4ab699e843d605b Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Thu, 3 Oct 2024 20:43:33 +0530
Subject: [PATCH 6/7] Add helper function for flag rewriting
---
.../InstCombine/InstCombineAddSub.cpp | 20 +++--
llvm/test/Transforms/InstCombine/fneg.ll | 76 +++++++++++++++++--
llvm/test/Transforms/InstCombine/fsub.ll | 2 +-
3 files changed, 84 insertions(+), 14 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 1ca2ee4674af2..7f373a3797b87 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2792,6 +2792,17 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
return TryToNarrowDeduceFlags();
}
+static FastMathFlags combineFastMathFlagsForFNeg(FastMathFlags FMF,
+ FastMathFlags OpFMF) {
+ FastMathFlags Flag = FMF | OpFMF;
+ Flag.setNoInfs(FMF.noInfs() && OpFMF.noInfs());
+ Flag.setAllowReassoc(FMF.allowReassoc() && OpFMF.allowReassoc());
+ Flag.setApproxFunc(FMF.approxFunc() && OpFMF.approxFunc());
+ Flag.setAllowReciprocal(FMF.allowReciprocal() && OpFMF.allowReciprocal());
+ Flag.setAllowContract(FMF.allowContract() && OpFMF.allowContract());
+ return Flag;
+}
+
/// This eliminates floating-point negation in either 'fneg(X)' or
/// 'fsub(-0.0, X)' form by combining into a constant operand.
static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
@@ -2809,11 +2820,10 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
- FastMathFlags FMF = I.getFastMathFlags();
- FastMathFlags OpFMF = FNegOp->getFastMathFlags();
- FastMathFlags Flag = FMF | OpFMF;
- Flag.setNoInfs(FMF.noInfs() && OpFMF.noInfs());
- return BinaryOperator::CreateFMulFMF(X, NegC, Flag);
+ return BinaryOperator::CreateFMulFMF(
+ X, NegC,
+ combineFastMathFlagsForFNeg(I.getFastMathFlags(),
+ FNegOp->getFastMathFlags()));
}
// -(X / C) --> X / (-C)
if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C))))
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index 968266f674227..adc1371d762ee 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -1204,8 +1204,8 @@ define float @test_fneg_ninf_mul_nsz_with_const(float %a) {
ret float %f2
}
-define <2 x float> @test_fneg_ninf_mul_nnan_with_vec_const(<2 x float> %a) {
-; CHECK-LABEL: @test_fneg_ninf_mul_nnan_with_vec_const(
+define <2 x float> @test_fneg_mul_combine_nnan_ninf_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_nnan_ninf_with_vec_const(
; CHECK-NEXT: [[F2:%.*]] = fmul nnan <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
; CHECK-NEXT: ret <2 x float> [[F2]]
;
@@ -1214,8 +1214,8 @@ define <2 x float> @test_fneg_ninf_mul_nnan_with_vec_const(<2 x float> %a) {
ret <2 x float> %f2
}
-define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
-; CHECK-LABEL: @test_fneg_ninf_mul_nsz_with_vec_const(
+define <2 x float> @test_fneg_mul_combine_nsz_ninf_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_nsz_ninf_with_vec_const(
; CHECK-NEXT: [[F2:%.*]] = fmul nsz <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
; CHECK-NEXT: ret <2 x float> [[F2]]
;
@@ -1224,8 +1224,8 @@ define <2 x float> @test_fneg_ninf_mul_nsz_with_vec_const(<2 x float> %a) {
ret <2 x float> %f2
}
-define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
-; CHECK-LABEL: @test_fneg_nnan_ninf_mul_with_vec_const(
+define <2 x float> @test_fneg_ninf_nnan_mul_with_vec_const(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_ninf_nnan_mul_with_vec_const(
; CHECK-NEXT: [[F2:%.*]] = fmul nnan <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
; CHECK-NEXT: ret <2 x float> [[F2]]
;
@@ -1234,8 +1234,8 @@ define <2 x float> @test_fneg_nnan_ninf_mul_with_vec_const(<2 x float> %a) {
ret <2 x float> %f2
}
-define <2 x float> @test_fneg_nnan_ninf_mul_ninf_with_vec_const(<2 x float> %a) {
-; CHECK-LABEL: @test_fneg_nnan_ninf_mul_ninf_with_vec_const(
+define <2 x float> @test_fneg_mul_combine_nnan_ninf_with_vec_const2(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_nnan_ninf_with_vec_const2(
; CHECK-NEXT: [[F2:%.*]] = fmul nnan ninf <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
; CHECK-NEXT: ret <2 x float> [[F2]]
;
@@ -1244,4 +1244,64 @@ define <2 x float> @test_fneg_nnan_ninf_mul_ninf_with_vec_const(<2 x float> %a)
ret <2 x float> %f2
}
+define <2 x float> @test_fneg_mul_combine_reassoc_ninf_with_vec_const1(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_reassoc_ninf_with_vec_const1(
+; CHECK-NEXT: [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul reassoc <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+define <2 x float> @test_fneg_mul_combine_reassoc_ninf_with_vec_const2(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_reassoc_ninf_with_vec_const2(
+; CHECK-NEXT: [[F2:%.*]] = fmul ninf <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul ninf <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg reassoc ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+define <2 x float> @test_fneg_mul_combine_reassoc_ninf_with_vec_const3(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_reassoc_ninf_with_vec_const3(
+; CHECK-NEXT: [[F2:%.*]] = fmul reassoc <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul reassoc <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg reassoc ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+define <2 x float> @test_fneg_mul_combine_contract_ninf_with_vec_const1(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_contract_ninf_with_vec_const1(
+; CHECK-NEXT: [[F2:%.*]] = fmul <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul contract <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+define <2 x float> @test_fneg_mul_combine_contract_ninf_with_vec_const2(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_contract_ninf_with_vec_const2(
+; CHECK-NEXT: [[F2:%.*]] = fmul ninf <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul ninf <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg contract ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
+define <2 x float> @test_fneg_mul_combine_contract_ninf_with_vec_const3(<2 x float> %a) {
+; CHECK-LABEL: @test_fneg_mul_combine_contract_ninf_with_vec_const3(
+; CHECK-NEXT: [[F2:%.*]] = fmul contract <2 x float> [[A:%.*]], <float -0.000000e+00, float 0.000000e+00>
+; CHECK-NEXT: ret <2 x float> [[F2]]
+;
+ %f1 = fmul contract <2 x float> %a, <float 0.000000, float -0.000000>
+ %f2 = fneg contract ninf <2 x float> %f1
+ ret <2 x float> %f2
+}
+
!0 = !{}
diff --git a/llvm/test/Transforms/InstCombine/fsub.ll b/llvm/test/Transforms/InstCombine/fsub.ll
index cffc63405ddcb..28cee50d72c12 100644
--- a/llvm/test/Transforms/InstCombine/fsub.ll
+++ b/llvm/test/Transforms/InstCombine/fsub.ll
@@ -98,7 +98,7 @@ define float @sub_sub_nsz(float %x, float %y, float %z) {
define float @sub_add_neg_x(float %x, float %y) {
; CHECK-LABEL: @sub_add_neg_x(
-; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -5.000000e+00
+; CHECK-NEXT: [[R:%.*]] = fmul nsz float [[X:%.*]], -5.000000e+00
; CHECK-NEXT: ret float [[R]]
;
%mul = fmul float %x, 5.000000e+00
>From 699be9077356dfe7d055c5f31397a46611be36d5 Mon Sep 17 00:00:00 2001
From: SahilPatidar <patidarsahil2001 at gmail.com>
Date: Sat, 15 Mar 2025 12:29:01 +0530
Subject: [PATCH 7/7] Update test
---
.../InstCombine/InstCombineAddSub.cpp | 21 ++++++-------------
llvm/test/Transforms/InstCombine/fneg.ll | 4 ++--
2 files changed, 8 insertions(+), 17 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 7f373a3797b87..bbdbb3a208ded 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2792,17 +2792,6 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
return TryToNarrowDeduceFlags();
}
-static FastMathFlags combineFastMathFlagsForFNeg(FastMathFlags FMF,
- FastMathFlags OpFMF) {
- FastMathFlags Flag = FMF | OpFMF;
- Flag.setNoInfs(FMF.noInfs() && OpFMF.noInfs());
- Flag.setAllowReassoc(FMF.allowReassoc() && OpFMF.allowReassoc());
- Flag.setApproxFunc(FMF.approxFunc() && OpFMF.approxFunc());
- Flag.setAllowReciprocal(FMF.allowReciprocal() && OpFMF.allowReciprocal());
- Flag.setAllowContract(FMF.allowContract() && OpFMF.allowContract());
- return Flag;
-}
-
/// This eliminates floating-point negation in either 'fneg(X)' or
/// 'fsub(-0.0, X)' form by combining into a constant operand.
static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
@@ -2820,10 +2809,12 @@ static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
// -(X * C) --> X * (-C)
if (match(FNegOp, m_FMul(m_Value(X), m_Constant(C))))
if (Constant *NegC = ConstantFoldUnaryOpOperand(Instruction::FNeg, C, DL)) {
- return BinaryOperator::CreateFMulFMF(
- X, NegC,
- combineFastMathFlagsForFNeg(I.getFastMathFlags(),
- FNegOp->getFastMathFlags()));
+ FastMathFlags FNegF = I.getFastMathFlags();
+ FastMathFlags OpF = FNegOp->getFastMathFlags();
+ FastMathFlags FMF = FastMathFlags::unionValue(FNegF, OpF) |
+ FastMathFlags::intersectRewrite(FNegF, OpF);
+ FMF.setNoInfs(FNegF.noInfs() && OpF.noInfs());
+ return BinaryOperator::CreateFMulFMF(X, NegC, FMF);
}
// -(X / C) --> X / (-C)
if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C))))
diff --git a/llvm/test/Transforms/InstCombine/fneg.ll b/llvm/test/Transforms/InstCombine/fneg.ll
index adc1371d762ee..507e7863deda0 100644
--- a/llvm/test/Transforms/InstCombine/fneg.ll
+++ b/llvm/test/Transforms/InstCombine/fneg.ll
@@ -42,7 +42,7 @@ define float @fmul_fneg(float %x) {
define float @fmul_fsub_fmf(float %x) {
; CHECK-LABEL: @fmul_fsub_fmf(
-; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT: [[R:%.*]] = fmul nsz float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%m = fmul float %x, 42.0
@@ -52,7 +52,7 @@ define float @fmul_fsub_fmf(float %x) {
define float @fmul_fneg_fmf(float %x) {
; CHECK-LABEL: @fmul_fneg_fmf(
-; CHECK-NEXT: [[R:%.*]] = fmul reassoc nsz float [[X:%.*]], -4.200000e+01
+; CHECK-NEXT: [[R:%.*]] = fmul nsz float [[X:%.*]], -4.200000e+01
; CHECK-NEXT: ret float [[R]]
;
%m = fmul float %x, 42.0
More information about the llvm-commits
mailing list