[llvm] [ConstantFold] Fold `ilogb` and `ilogbf` when the input parameter is a constant value. (PR #113014)
via llvm-commits
llvm-commits at lists.llvm.org
Sat Oct 19 06:34:51 PDT 2024
https://github.com/c8ef updated https://github.com/llvm/llvm-project/pull/113014
>From 7b851310dcf46e8f486b7e4c71e2280431f51201 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sat, 19 Oct 2024 09:28:21 +0800
Subject: [PATCH 1/3] constant fold ilogb
---
llvm/lib/Analysis/ConstantFolding.cpp | 21 ++-
llvm/test/Transforms/InstCombine/ilogb.ll | 203 ++++++++++++++++++++++
2 files changed, 223 insertions(+), 1 deletion(-)
create mode 100644 llvm/test/Transforms/InstCombine/ilogb.ll
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 74df67a4ff9b43..d9eea2cc2915bb 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1677,6 +1677,8 @@ bool llvm::canConstantFoldCallTo(const CallBase *Call, const Function *F) {
return Name == "fabs" || Name == "fabsf" ||
Name == "floor" || Name == "floorf" ||
Name == "fmod" || Name == "fmodf";
+ case 'i':
+ return Name == "ilogb" || Name == "ilogbf";
case 'l':
return Name == "log" || Name == "logf" || Name == "logl" ||
Name == "log2" || Name == "log2f" || Name == "log10" ||
@@ -1772,6 +1774,17 @@ inline bool llvm_fenv_testexcept() {
return false;
}
+Constant *ConstantFoldInt(int (*NativeFP)(double), const APFloat &V, Type *Ty) {
+ llvm_fenv_clearexcept();
+ int Result = NativeFP(V.convertToDouble());
+ if (llvm_fenv_testexcept()) {
+ llvm_fenv_clearexcept();
+ return nullptr;
+ }
+
+ return ConstantInt::get(Ty, Result, true);
+}
+
Constant *ConstantFoldFP(double (*NativeFP)(double), const APFloat &V,
Type *Ty) {
llvm_fenv_clearexcept();
@@ -2131,7 +2144,8 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
}
#endif
- if (!Ty->isHalfTy() && !Ty->isFloatTy() && !Ty->isDoubleTy())
+ if (!Ty->isHalfTy() && !Ty->isFloatTy() && !Ty->isDoubleTy() &&
+ !Ty->isIntegerTy())
return nullptr;
// Use internal versions of these intrinsics.
@@ -2391,6 +2405,11 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
// TODO: What about hosts that lack a C99 library?
return ConstantFoldFP(log10, APF, Ty);
break;
+ case LibFunc_ilogb:
+ case LibFunc_ilogbf:
+ if (!APF.isZero() && TLI->has(Func))
+ return ConstantFoldInt(ilogb, APF, Ty);
+ break;
case LibFunc_logb:
case LibFunc_logbf:
if (!APF.isZero() && TLI->has(Func))
diff --git a/llvm/test/Transforms/InstCombine/ilogb.ll b/llvm/test/Transforms/InstCombine/ilogb.ll
new file mode 100644
index 00000000000000..e30791fe68e7b2
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/ilogb.ll
@@ -0,0 +1,203 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+define i32 @ilogbf_const1() {
+; CHECK-LABEL: define i32 @ilogbf_const1() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 7.000000e+00)
+; CHECK-NEXT: ret i32 2
+;
+ %r = call i32 @ilogbf(float 7.000000e+00)
+ ret i32 %r
+}
+
+define i32 @ilogb_const1() {
+; CHECK-LABEL: define i32 @ilogb_const1() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double -7.000000e+00)
+; CHECK-NEXT: ret i32 2
+;
+ %r = call i32 @ilogb(double -7.000000e+00)
+ ret i32 %r
+}
+
+define i32 @ilogbf_const2() {
+; CHECK-LABEL: define i32 @ilogbf_const2() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 5.000000e-01)
+; CHECK-NEXT: ret i32 -1
+;
+ %r = call i32 @ilogbf(float 5.000000e-01)
+ ret i32 %r
+}
+
+define i32 @ilogb_const2() {
+; CHECK-LABEL: define i32 @ilogb_const2() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double -5.000000e-01)
+; CHECK-NEXT: ret i32 -1
+;
+ %r = call i32 @ilogb(double -5.000000e-01)
+ ret i32 %r
+}
+
+define i32 @ilogbf_zero() {
+; CHECK-LABEL: define i32 @ilogbf_zero() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 0.000000e+00)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float 0.000000e+00)
+ ret i32 %r
+}
+
+define i32 @ilogb_zero() {
+; CHECK-LABEL: define i32 @ilogb_zero() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double 0.000000e+00)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double 0.000000e+00)
+ ret i32 %r
+}
+
+define i32 @ilogbf_neg_zero() {
+; CHECK-LABEL: define i32 @ilogbf_neg_zero() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float -0.000000e+00)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float -0.000000e+00)
+ ret i32 %r
+}
+
+define i32 @ilogb_neg_zero() {
+; CHECK-LABEL: define i32 @ilogb_neg_zero() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double -0.000000e+00)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double -0.000000e+00)
+ ret i32 %r
+}
+
+define i32 @ilogbf_inf() {
+; CHECK-LABEL: define i32 @ilogbf_inf() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 0x7FF0000000000000)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float 0x7FF0000000000000)
+ ret i32 %r
+}
+
+define i32 @ilogb_inf() {
+; CHECK-LABEL: define i32 @ilogb_inf() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double 0x7FF0000000000000)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double 0x7FF0000000000000)
+ ret i32 %r
+}
+
+define i32 @ilogbf_nan() {
+; CHECK-LABEL: define i32 @ilogbf_nan() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 0x7FF8000000000000)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float 0x7FF8000000000000)
+ ret i32 %r
+}
+
+define i32 @ilogb_nan() {
+; CHECK-LABEL: define i32 @ilogb_nan() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double 0x7FF8000000000000)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double 0x7FF8000000000000)
+ ret i32 %r
+}
+
+define i32 @ilogbf_zero_readnone() {
+; CHECK-LABEL: define i32 @ilogbf_zero_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 0.000000e+00) #[[ATTR0:[0-9]+]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float 0.000000e+00) readnone
+ ret i32 %r
+}
+
+define i32 @ilogb_zero_readnone() {
+; CHECK-LABEL: define i32 @ilogb_zero_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double 0.000000e+00) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double 0.000000e+00) readnone
+ ret i32 %r
+}
+
+define i32 @ilogbf_neg_zero_readnone() {
+; CHECK-LABEL: define i32 @ilogbf_neg_zero_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float -0.000000e+00) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float -0.000000e+00) readnone
+ ret i32 %r
+}
+
+define i32 @ilogb_neg_zero_readnone() {
+; CHECK-LABEL: define i32 @ilogb_neg_zero_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double -0.000000e+00) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double -0.000000e+00) readnone
+ ret i32 %r
+}
+
+define i32 @ilogbf_inf_readnone() {
+; CHECK-LABEL: define i32 @ilogbf_inf_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 0x7FF0000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float 0x7FF0000000000000) readnone
+ ret i32 %r
+}
+
+define i32 @ilogb_inf_readnone() {
+; CHECK-LABEL: define i32 @ilogb_inf_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double 0x7FF0000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double 0x7FF0000000000000) readnone
+ ret i32 %r
+}
+
+define i32 @ilogbf_nan_readnone() {
+; CHECK-LABEL: define i32 @ilogbf_nan_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float 0x7FF8000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float 0x7FF8000000000000) readnone
+ ret i32 %r
+}
+
+define i32 @ilogb_nan_readnone() {
+; CHECK-LABEL: define i32 @ilogb_nan_readnone() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double 0x7FF8000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double 0x7FF8000000000000) readnone
+ ret i32 %r
+}
+
+define i32 @ilogbf_poison() {
+; CHECK-LABEL: define i32 @ilogbf_poison() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogbf(float poison)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogbf(float poison)
+ ret i32 %r
+}
+
+define i32 @ilogb_poison() {
+; CHECK-LABEL: define i32 @ilogb_poison() {
+; CHECK-NEXT: [[R:%.*]] = call i32 @ilogb(double poison)
+; CHECK-NEXT: ret i32 [[R]]
+;
+ %r = call i32 @ilogb(double poison)
+ ret i32 %r
+}
+
+declare i32 @ilogbf(float)
+declare i32 @ilogb(double)
>From c2d1a1616bd5e2f2b7f3333f93799881c34da21f Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sat, 19 Oct 2024 13:02:29 +0800
Subject: [PATCH 2/3] address review comments
---
llvm/lib/Analysis/ConstantFolding.cpp | 13 +------------
1 file changed, 1 insertion(+), 12 deletions(-)
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index d9eea2cc2915bb..c0104d2bc26112 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1774,17 +1774,6 @@ inline bool llvm_fenv_testexcept() {
return false;
}
-Constant *ConstantFoldInt(int (*NativeFP)(double), const APFloat &V, Type *Ty) {
- llvm_fenv_clearexcept();
- int Result = NativeFP(V.convertToDouble());
- if (llvm_fenv_testexcept()) {
- llvm_fenv_clearexcept();
- return nullptr;
- }
-
- return ConstantInt::get(Ty, Result, true);
-}
-
Constant *ConstantFoldFP(double (*NativeFP)(double), const APFloat &V,
Type *Ty) {
llvm_fenv_clearexcept();
@@ -2408,7 +2397,7 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
case LibFunc_ilogb:
case LibFunc_ilogbf:
if (!APF.isZero() && TLI->has(Func))
- return ConstantFoldInt(ilogb, APF, Ty);
+ return ConstantInt::get(Ty, ilogb(APF), true);
break;
case LibFunc_logb:
case LibFunc_logbf:
>From 5f1f69368e1f17ff9e32428f36cf34ffb6255ae5 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Sat, 19 Oct 2024 21:34:42 +0800
Subject: [PATCH 3/3] try deleting check
---
llvm/lib/Analysis/ConstantFolding.cpp | 5 -----
1 file changed, 5 deletions(-)
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index c0104d2bc26112..2a345c2f36d4b0 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -2133,12 +2133,7 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
}
#endif
- if (!Ty->isHalfTy() && !Ty->isFloatTy() && !Ty->isDoubleTy() &&
- !Ty->isIntegerTy())
- return nullptr;
-
// Use internal versions of these intrinsics.
-
if (IntrinsicID == Intrinsic::nearbyint || IntrinsicID == Intrinsic::rint) {
U.roundToIntegral(APFloat::rmNearestTiesToEven);
return ConstantFP::get(Ty->getContext(), U);
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