[llvm] [InstCombine] Add fold for fabs(-x) -> fabs(x) (PR #94183)
Yingwei Zheng via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 3 02:05:43 PDT 2024
================
@@ -0,0 +1,57 @@
+; RUN: opt -S -passes=instcombine %s | FileCheck %s
+
+define float @fabs_fneg_f32(float %x) {
+; CHECK-LABEL: define float @fabs_fneg_f32(
+; CHECK-NEXT: [[FABS:%.*]] = call float @llvm.fabs.f32(float [[X:%.*]])
+; CHECK-NEXT: ret float [[FABS]]
+;
+ %neg = fneg float %x
+ %fabs = call float @llvm.fabs.f32(float %neg)
+ ret float %fabs
+}
+
+define <2 x float> @fabs_fneg_v2f32(<2 x float> %x) {
+; CHECK-LABEL: define <2 x float> @fabs_fneg_v2f32(
+; CHECK-NEXT: [[FABS:%.*]] = call <2 x float> @llvm.fabs.v2f32(<2 x float> [[X:%.*]])
+; CHECK-NEXT: ret <2 x float> [[FABS]]
+;
+ %neg = fneg <2 x float> %x
+ %fabs = call <2 x float> @llvm.fabs.v2f32(<2 x float> %neg)
+ ret <2 x float> %fabs
+}
+
+define double @fabs_fneg_f64(double %x) {
+; CHECK-LABEL: define double @fabs_fneg_f64(
+; CHECK-NEXT: [[FABS:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT: ret double [[FABS]]
+;
+ %neg = fneg double %x
+ %fabs = call double @llvm.fabs.f64(double %neg)
+ ret double %fabs
+}
+
+define <4 x double> @fabs_fneg_v4f64(<4 x double> %x) {
+; CHECK-LABEL: define <4 x double> @fabs_fneg_v4f64(
+; CHECK-NEXT: [[FABS:%.*]] = call <4 x double> @llvm.fabs.v4f64(<4 x double> [[X:%.*]])
+; CHECK-NEXT: ret <4 x double> [[FABS]]
+;
+ %neg = fneg <4 x double> %x
+ %fabs = call <4 x double> @llvm.fabs.v4f64(<4 x double> %neg)
+ ret <4 x double> %fabs
+}
+
+define half @fabs_fneg_f16(half %x) {
+; CHECK-LABEL: define half @fabs_fneg_f16(
+; CHECK-NEXT: [[FABS:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
+; CHECK-NEXT: ret half [[FABS]]
+;
+ %neg = fneg half %x
+ %fabs = call half @llvm.fabs.f16(half %neg)
+ ret half %fabs
+}
+
+declare float @llvm.fabs.f32(float)
----------------
dtcxzyw wrote:
These declarations are unnecessary.
https://github.com/llvm/llvm-project/pull/94183
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