[llvm] [SimplifyLibCalls] Shrink sin, cos to sinf, cosf when allowed (PR #139082)

[Matt Arsenault via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instcombine -S                             | FileCheck %s --check-prefixes=ANY,NO-FLOAT-SHRINK
+; RUN: opt < %s -passes=instcombine -enable-double-float-shrink -S | FileCheck %s --check-prefixes=ANY,DO-FLOAT-SHRINK
+
+declare double @llvm.cos.f64(double)
+declare float @llvm.cos.f32(float)
+
+declare double @llvm.sin.f64(double)
+declare float @llvm.sin.f32(float)
+
+; cos -> cosf
+
+define float @cos_no_fastmath(float %f) {
+; NO-FLOAT-SHRINK-LABEL: @cos_no_fastmath(
+; NO-FLOAT-SHRINK-NEXT:    [[D:%.*]] = fpext float [[F:%.*]] to double
+; NO-FLOAT-SHRINK-NEXT:    [[RESULT:%.*]] = call double @llvm.cos.f64(double [[D]])
+; NO-FLOAT-SHRINK-NEXT:    [[TRUNCATED_RESULT:%.*]] = fptrunc double [[RESULT]] to float
+; NO-FLOAT-SHRINK-NEXT:    ret float [[TRUNCATED_RESULT]]
+;
+; DO-FLOAT-SHRINK-LABEL: @cos_no_fastmath(
+; DO-FLOAT-SHRINK-NEXT:    [[TMP1:%.*]] = call float @llvm.cos.f32(float [[F:%.*]])
+; DO-FLOAT-SHRINK-NEXT:    ret float [[TMP1]]
+;
+  %d = fpext float %f to double
+  %result = call double @llvm.cos.f64(double %d)
+  %truncated_result = fptrunc double %result to float
+  ret float %truncated_result
+}
+
+define float @cos_fastmath(float %f) {
+; ANY-LABEL: @cos_fastmath(
+; ANY-NEXT:    [[TMP1:%.*]] = call fast float @llvm.cos.f32(float [[F:%.*]])
+; ANY-NEXT:    ret float [[TMP1]]
+;
+  %d = fpext float %f to double
+  %result = call fast double @llvm.cos.f64(double %d)
+  %truncated_result = fptrunc double %result to float
+  ret float %truncated_result
+}
+
+; sin -> sinf
+
+define float @sin_no_fastmath(float %f) {
+; NO-FLOAT-SHRINK-LABEL: @sin_no_fastmath(
+; NO-FLOAT-SHRINK-NEXT:    [[D:%.*]] = fpext float [[F:%.*]] to double
+; NO-FLOAT-SHRINK-NEXT:    [[RESULT:%.*]] = call double @llvm.sin.f64(double [[D]])
+; NO-FLOAT-SHRINK-NEXT:    [[TRUNCATED_RESULT:%.*]] = fptrunc double [[RESULT]] to float
+; NO-FLOAT-SHRINK-NEXT:    ret float [[TRUNCATED_RESULT]]
+;
+; DO-FLOAT-SHRINK-LABEL: @sin_no_fastmath(
+; DO-FLOAT-SHRINK-NEXT:    [[TMP1:%.*]] = call float @llvm.sin.f32(float [[F:%.*]])
+; DO-FLOAT-SHRINK-NEXT:    ret float [[TMP1]]
+;
+  %d = fpext float %f to double
+  %result = call double @llvm.sin.f64(double %d)
+  %truncated_result = fptrunc double %result to float
+  ret float %truncated_result
+}
+
+define float @sin_fastmath(float %f) {
+; ANY-LABEL: @sin_fastmath(
+; ANY-NEXT:    [[TMP1:%.*]] = call fast float @llvm.sin.f32(float [[F:%.*]])
+; ANY-NEXT:    ret float [[TMP1]]
+;
+  %d = fpext float %f to double
+  %result = call fast double @llvm.sin.f64(double %d)
+  %truncated_result = fptrunc double %result to float
+  ret float %truncated_result
+}
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arsenm wrote:

Also test vector case 

https://github.com/llvm/llvm-project/pull/139082