[llvm] [InstCombine] fold `ldexp(x, zext(i1 y))` to `fmul x, (select y, 2.0, 1.0)` (PR #94887)
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llvm-commits at lists.llvm.org
Sun Jun 9 18:10:27 PDT 2024
https://github.com/c8ef updated https://github.com/llvm/llvm-project/pull/94887
>From 00af1fbb6311694303ff6e161d122cdf1dc8f646 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sun, 9 Jun 2024 11:24:47 +0800
Subject: [PATCH 1/5] ldexp(x, zext(i1 y))
---
.../InstCombine/InstCombineCalls.cpp | 13 ++++++++++
.../test/Transforms/InstCombine/ldexp-zext.ll | 24 +++++++++++++++++++
2 files changed, 37 insertions(+)
create mode 100644 llvm/test/Transforms/InstCombine/ldexp-zext.ll
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 0632f3cfc6dd2..15c11799b949e 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2618,6 +2618,19 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
}
}
+ // ldexp(x, zext(i1 y)) -> fmul x, (select y, 2.0, 1.0)
+ Value *ExtSrc;
+ if (match(Exp, m_ZExt(m_Value(ExtSrc))) &&
+ ExtSrc->getType()->getScalarSizeInBits() == 1) {
+ Value *Cmp = Builder.CreateICmp(
+ ICmpInst::ICMP_NE, ExtSrc, Constant::getNullValue(ExtSrc->getType()));
+ SelectInst *Select = SelectInst::Create(
+ Cmp, ConstantFP::get(Type::getFloatTy(II->getContext()), 2.0),
+ ConstantFP::get(Type::getFloatTy(II->getContext()), 1.0));
+ Builder.Insert(Select);
+ return BinaryOperator::CreateFMul(Src, Select);
+ }
+
break;
}
case Intrinsic::ptrauth_auth:
diff --git a/llvm/test/Transforms/InstCombine/ldexp-zext.ll b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
new file mode 100644
index 0000000000000..998a8d321342c
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
@@ -0,0 +1,24 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+define float @ldexp_zext(float %x, i1 %bool) {
+; CHECK-LABEL: @ldexp_zext(
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[BOOL:%.*]], float 2.000000e+00, float 1.000000e+00
+; CHECK-NEXT: [[LDEXP:%.*]] = fmul float [[TMP1]], [[X:%.*]]
+; CHECK-NEXT: ret float [[LDEXP]]
+;
+ %zext = zext i1 %bool to i32
+ %ldexp = call float @llvm.ldexp.f32.i32(float %x, i32 %zext)
+ ret float %ldexp
+}
+
+define float @ldexp_zext_negative(float %x, i8 %y) {
+; CHECK-LABEL: @ldexp_zext_negative(
+; CHECK-NEXT: [[ZEXT:%.*]] = zext i8 [[Y:%.*]] to i32
+; CHECK-NEXT: [[LDEXP:%.*]] = call float @llvm.ldexp.f32.i32(float [[X:%.*]], i32 [[ZEXT]])
+; CHECK-NEXT: ret float [[LDEXP]]
+;
+ %zext = zext i8 %y to i32
+ %ldexp = call float @llvm.ldexp.f32.i32(float %x, i32 %zext)
+ ret float %ldexp
+}
>From fb274bb1b623bad167303f6630a110aac7d7b14e Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sun, 9 Jun 2024 16:58:54 +0800
Subject: [PATCH 2/5] address CR comments
---
.../InstCombine/InstCombineCalls.cpp | 7 ++---
.../test/Transforms/InstCombine/ldexp-zext.ll | 30 ++++++++++++++++---
2 files changed, 29 insertions(+), 8 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 15c11799b949e..e0310106cd5d7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2624,10 +2624,9 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
ExtSrc->getType()->getScalarSizeInBits() == 1) {
Value *Cmp = Builder.CreateICmp(
ICmpInst::ICMP_NE, ExtSrc, Constant::getNullValue(ExtSrc->getType()));
- SelectInst *Select = SelectInst::Create(
- Cmp, ConstantFP::get(Type::getFloatTy(II->getContext()), 2.0),
- ConstantFP::get(Type::getFloatTy(II->getContext()), 1.0));
- Builder.Insert(Select);
+ Value *Select =
+ Builder.CreateSelect(Cmp, ConstantFP::get(II->getType(), 2.0),
+ ConstantFP::get(II->getType(), 1.0));
return BinaryOperator::CreateFMul(Src, Select);
}
diff --git a/llvm/test/Transforms/InstCombine/ldexp-zext.ll b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
index 998a8d321342c..a89ccd7cca120 100644
--- a/llvm/test/Transforms/InstCombine/ldexp-zext.ll
+++ b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
@@ -1,8 +1,8 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
-define float @ldexp_zext(float %x, i1 %bool) {
-; CHECK-LABEL: @ldexp_zext(
+define float @ldexp_zext_float(float %x, i1 %bool) {
+; CHECK-LABEL: @ldexp_zext_float(
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[BOOL:%.*]], float 2.000000e+00, float 1.000000e+00
; CHECK-NEXT: [[LDEXP:%.*]] = fmul float [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret float [[LDEXP]]
@@ -12,8 +12,8 @@ define float @ldexp_zext(float %x, i1 %bool) {
ret float %ldexp
}
-define float @ldexp_zext_negative(float %x, i8 %y) {
-; CHECK-LABEL: @ldexp_zext_negative(
+define float @ldexp_zext_float_negative(float %x, i8 %y) {
+; CHECK-LABEL: @ldexp_zext_float_negative(
; CHECK-NEXT: [[ZEXT:%.*]] = zext i8 [[Y:%.*]] to i32
; CHECK-NEXT: [[LDEXP:%.*]] = call float @llvm.ldexp.f32.i32(float [[X:%.*]], i32 [[ZEXT]])
; CHECK-NEXT: ret float [[LDEXP]]
@@ -22,3 +22,25 @@ define float @ldexp_zext_negative(float %x, i8 %y) {
%ldexp = call float @llvm.ldexp.f32.i32(float %x, i32 %zext)
ret float %ldexp
}
+
+define double @ldexp_zext_double(double %x, i1 %bool) {
+; CHECK-LABEL: @ldexp_zext_double(
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[BOOL:%.*]], double 2.000000e+00, double 1.000000e+00
+; CHECK-NEXT: [[LDEXP:%.*]] = fmul double [[TMP1]], [[X:%.*]]
+; CHECK-NEXT: ret double [[LDEXP]]
+;
+ %zext = zext i1 %bool to i32
+ %ldexp = call double @llvm.ldexp.f32.i32(double %x, i32 %zext)
+ ret double %ldexp
+}
+
+define <2 x float> @ldexp_zext_float_vector(<2 x float> %x, <2 x i1> %bool) {
+; CHECK-LABEL: @ldexp_zext_float_vector(
+; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[BOOL:%.*]], <2 x float> <float 2.000000e+00, float 2.000000e+00>, <2 x float> <float 1.000000e+00, float 1.000000e+00>
+; CHECK-NEXT: [[LDEXP:%.*]] = fmul <2 x float> [[TMP1]], [[X:%.*]]
+; CHECK-NEXT: ret <2 x float> [[LDEXP]]
+;
+ %zext = zext <2 x i1> %bool to <2 x i32>
+ %ldexp = call <2 x float> @llvm.ldexp.v2f32.v2i32(<2 x float> %x, <2 x i32> %zext)
+ ret <2 x float> %ldexp
+}
>From edc40e408d155ee28d713d9d5678ca6873ecd77f Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sun, 9 Jun 2024 20:39:35 +0800
Subject: [PATCH 3/5] remove useless icmp
---
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index e0310106cd5d7..38ff23dd1c08f 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2622,10 +2622,8 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
Value *ExtSrc;
if (match(Exp, m_ZExt(m_Value(ExtSrc))) &&
ExtSrc->getType()->getScalarSizeInBits() == 1) {
- Value *Cmp = Builder.CreateICmp(
- ICmpInst::ICMP_NE, ExtSrc, Constant::getNullValue(ExtSrc->getType()));
Value *Select =
- Builder.CreateSelect(Cmp, ConstantFP::get(II->getType(), 2.0),
+ Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 2.0),
ConstantFP::get(II->getType(), 1.0));
return BinaryOperator::CreateFMul(Src, Select);
}
>From 270482c50d8c619ddbb18756f863a15045514240 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sun, 9 Jun 2024 21:33:22 +0800
Subject: [PATCH 4/5] preserve fast math flag; add test about it
---
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp | 2 +-
llvm/test/Transforms/InstCombine/ldexp-zext.ll | 11 +++++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 38ff23dd1c08f..4346a07e3a2cb 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2625,7 +2625,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
Value *Select =
Builder.CreateSelect(ExtSrc, ConstantFP::get(II->getType(), 2.0),
ConstantFP::get(II->getType(), 1.0));
- return BinaryOperator::CreateFMul(Src, Select);
+ return BinaryOperator::CreateFMulFMF(Src, Select, II);
}
break;
diff --git a/llvm/test/Transforms/InstCombine/ldexp-zext.ll b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
index a89ccd7cca120..38465920fe0af 100644
--- a/llvm/test/Transforms/InstCombine/ldexp-zext.ll
+++ b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
@@ -34,6 +34,17 @@ define double @ldexp_zext_double(double %x, i1 %bool) {
ret double %ldexp
}
+define double @ldexp_zext_double_fast_math(double %x, i1 %bool) {
+; CHECK-LABEL: @ldexp_zext_double_fast_math(
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[BOOL:%.*]], double 2.000000e+00, double 1.000000e+00
+; CHECK-NEXT: [[LDEXP:%.*]] = fmul fast double [[TMP1]], [[X:%.*]]
+; CHECK-NEXT: ret double [[LDEXP]]
+;
+ %zext = zext i1 %bool to i32
+ %ldexp = call fast double @llvm.ldexp.f32.i32(double %x, i32 %zext)
+ ret double %ldexp
+}
+
define <2 x float> @ldexp_zext_float_vector(<2 x float> %x, <2 x i1> %bool) {
; CHECK-LABEL: @ldexp_zext_float_vector(
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[BOOL:%.*]], <2 x float> <float 2.000000e+00, float 2.000000e+00>, <2 x float> <float 1.000000e+00, float 1.000000e+00>
>From 5caee727edb86b0e9781fd02690e0a931a7eb9a7 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Mon, 10 Jun 2024 09:10:10 +0800
Subject: [PATCH 5/5] fix test
---
llvm/test/Transforms/InstCombine/ldexp-zext.ll | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/llvm/test/Transforms/InstCombine/ldexp-zext.ll b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
index 38465920fe0af..b6e4f12494059 100644
--- a/llvm/test/Transforms/InstCombine/ldexp-zext.ll
+++ b/llvm/test/Transforms/InstCombine/ldexp-zext.ll
@@ -30,18 +30,18 @@ define double @ldexp_zext_double(double %x, i1 %bool) {
; CHECK-NEXT: ret double [[LDEXP]]
;
%zext = zext i1 %bool to i32
- %ldexp = call double @llvm.ldexp.f32.i32(double %x, i32 %zext)
+ %ldexp = call double @llvm.ldexp.f64.i32(double %x, i32 %zext)
ret double %ldexp
}
define double @ldexp_zext_double_fast_math(double %x, i1 %bool) {
; CHECK-LABEL: @ldexp_zext_double_fast_math(
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[BOOL:%.*]], double 2.000000e+00, double 1.000000e+00
-; CHECK-NEXT: [[LDEXP:%.*]] = fmul fast double [[TMP1]], [[X:%.*]]
+; CHECK-NEXT: [[LDEXP:%.*]] = fmul reassoc double [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret double [[LDEXP]]
;
%zext = zext i1 %bool to i32
- %ldexp = call fast double @llvm.ldexp.f32.i32(double %x, i32 %zext)
+ %ldexp = call reassoc double @llvm.ldexp.f64.i32(double %x, i32 %zext)
ret double %ldexp
}
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