[llvm] [ConstantFold] Fold `erf` and `erff` when the input parameter is a constant value. (PR #113079)
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Sun Oct 20 04:33:25 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-analysis
Author: None (c8ef)
<details>
<summary>Changes</summary>
This patch adds support for constant folding for the `erf` and `erff` libc functions.
---
Full diff: https://github.com/llvm/llvm-project/pull/113079.diff
2 Files Affected:
- (modified) llvm/lib/Analysis/ConstantFolding.cpp (+7-2)
- (added) llvm/test/Transforms/InstCombine/erf.ll (+185)
``````````diff
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index c0104d2bc26112..082df2972dfda1 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1671,8 +1671,8 @@ bool llvm::canConstantFoldCallTo(const CallBase *Call, const Function *F) {
Name == "cos" || Name == "cosf" ||
Name == "cosh" || Name == "coshf";
case 'e':
- return Name == "exp" || Name == "expf" ||
- Name == "exp2" || Name == "exp2f";
+ return Name == "exp" || Name == "expf" || Name == "exp2" ||
+ Name == "exp2f" || Name == "erf" || Name == "erff";
case 'f':
return Name == "fabs" || Name == "fabsf" ||
Name == "floor" || Name == "floorf" ||
@@ -2411,6 +2411,11 @@ static Constant *ConstantFoldScalarCall1(StringRef Name,
break;
case LibFunc_logl:
return nullptr;
+ case LibFunc_erf:
+ case LibFunc_erff:
+ if (TLI->has(Func))
+ return ConstantFoldFP(erf, APF, Ty);
+ break;
case LibFunc_nearbyint:
case LibFunc_nearbyintf:
case LibFunc_rint:
diff --git a/llvm/test/Transforms/InstCombine/erf.ll b/llvm/test/Transforms/InstCombine/erf.ll
new file mode 100644
index 00000000000000..e2f1abca074669
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/erf.ll
@@ -0,0 +1,185 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+define float @erff_const() {
+; CHECK-LABEL: define float @erff_const() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 5.000000e-01)
+; CHECK-NEXT: ret float 0x3FE0A7EF60000000
+;
+ %r = call float @erff(float 5.000000e-01)
+ ret float %r
+}
+
+define double @erf_const() {
+; CHECK-LABEL: define double @erf_const() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double -5.000000e-01)
+; CHECK-NEXT: ret double 0xBFE0A7EF5C18EDD2
+;
+ %r = call double @erf(double -5.000000e-01)
+ ret double %r
+}
+
+define float @erff_zero() {
+; CHECK-LABEL: define float @erff_zero() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0.000000e+00)
+; CHECK-NEXT: ret float 0.000000e+00
+;
+ %r = call float @erff(float 0.000000e+00)
+ ret float %r
+}
+
+define double @erf_zero() {
+; CHECK-LABEL: define double @erf_zero() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0.000000e+00)
+; CHECK-NEXT: ret double 0.000000e+00
+;
+ %r = call double @erf(double 0.000000e+00)
+ ret double %r
+}
+
+define float @erff_neg_zero() {
+; CHECK-LABEL: define float @erff_neg_zero() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float -0.000000e+00)
+; CHECK-NEXT: ret float -0.000000e+00
+;
+ %r = call float @erff(float -0.000000e+00)
+ ret float %r
+}
+
+define double @erf_neg_zero() {
+; CHECK-LABEL: define double @erf_neg_zero() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double -0.000000e+00)
+; CHECK-NEXT: ret double -0.000000e+00
+;
+ %r = call double @erf(double -0.000000e+00)
+ ret double %r
+}
+
+define float @erff_inf() {
+; CHECK-LABEL: define float @erff_inf() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0x7FF0000000000000)
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float 0x7FF0000000000000)
+ ret float %r
+}
+
+define double @erf_inf() {
+; CHECK-LABEL: define double @erf_inf() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0x7FF0000000000000)
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double 0x7FF0000000000000)
+ ret double %r
+}
+
+define float @erff_inf_memory_none() {
+; CHECK-LABEL: define float @erff_inf_memory_none() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0x7FF0000000000000) #[[ATTR0:[0-9]+]]
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float 0x7FF0000000000000) readnone
+ ret float %r
+}
+
+define double @erf_inf_memory_none() {
+; CHECK-LABEL: define double @erf_inf_memory_none() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0x7FF0000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double 0x7FF0000000000000) readnone
+ ret double %r
+}
+
+define float @erff_neg_inf() {
+; CHECK-LABEL: define float @erff_neg_inf() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0xFFF0000000000000)
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float 0xFFF0000000000000)
+ ret float %r
+}
+
+define double @erf_neg_inf() {
+; CHECK-LABEL: define double @erf_neg_inf() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0xFFF0000000000000)
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double 0xFFF0000000000000)
+ ret double %r
+}
+
+define float @erff_neg_inf_memory_none() {
+; CHECK-LABEL: define float @erff_neg_inf_memory_none() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0xFFF0000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float 0xFFF0000000000000) readnone
+ ret float %r
+}
+
+define double @erf_neg_inf_memory_none() {
+; CHECK-LABEL: define double @erf_neg_inf_memory_none() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0xFFF0000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double 0xFFF0000000000000) readnone
+ ret double %r
+}
+
+define float @erff_nan() {
+; CHECK-LABEL: define float @erff_nan() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0x7FF8000000000000)
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float 0x7FF8000000000000)
+ ret float %r
+}
+
+define double @erf_nan() {
+; CHECK-LABEL: define double @erf_nan() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0x7FF8000000000000)
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double 0x7FF8000000000000)
+ ret double %r
+}
+
+define float @erff_nan_memory_none() {
+; CHECK-LABEL: define float @erff_nan_memory_none() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float 0x7FF8000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float 0x7FF8000000000000) readnone
+ ret float %r
+}
+
+define double @erf_nan_memory_none() {
+; CHECK-LABEL: define double @erf_nan_memory_none() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double 0x7FF8000000000000) #[[ATTR0]]
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double 0x7FF8000000000000) readnone
+ ret double %r
+}
+
+define float @erff_poison() {
+; CHECK-LABEL: define float @erff_poison() {
+; CHECK-NEXT: [[R:%.*]] = call float @erff(float poison)
+; CHECK-NEXT: ret float [[R]]
+;
+ %r = call float @erff(float poison)
+ ret float %r
+}
+
+define double @erf_poison() {
+; CHECK-LABEL: define double @erf_poison() {
+; CHECK-NEXT: [[R:%.*]] = call double @erf(double poison)
+; CHECK-NEXT: ret double [[R]]
+;
+ %r = call double @erf(double poison)
+ ret double %r
+}
+
+declare float @erff(float)
+declare double @erf(double)
``````````
</details>
https://github.com/llvm/llvm-project/pull/113079
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