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amordoamordo
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[InstCombine] Fold tan(x) * cos(x) => sin(x) (#136319)
This patch enables folding `tan(x) * cos(x) -> sin(x)` under the `contract` flag. Fixes #34950.
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‎llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

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@@ -1072,6 +1072,18 @@ Instruction *InstCombinerImpl::visitFMul(BinaryOperator &I) {
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return Result;
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}
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// tan(X) * cos(X) -> sin(X)
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if (I.hasAllowContract() &&
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match(&I,
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m_c_FMul(m_OneUse(m_Intrinsic<Intrinsic::tan>(m_Value(X))),
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m_OneUse(m_Intrinsic<Intrinsic::cos>(m_Deferred(X)))))) {
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auto *Sin = Builder.CreateUnaryIntrinsic(Intrinsic::sin, X, &I);
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if (auto *Metadata = I.getMetadata(LLVMContext::MD_fpmath)) {
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Sin->setMetadata(LLVMContext::MD_fpmath, Metadata);
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}
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return replaceInstUsesWith(I, Sin);
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}
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return nullptr;
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}
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‎llvm/test/Transforms/InstCombine/fmul-tan-cos.ll

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
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; RUN: opt -S -passes=instcombine < %s | FileCheck %s
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define double @fmul_tan_cos(double %a) {
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; CHECK-LABEL: define double @fmul_tan_cos(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[TAN:%.*]] = call double @llvm.tan.f64(double [[A]])
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; CHECK-NEXT: [[COS:%.*]] = call double @llvm.cos.f64(double [[A]])
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; CHECK-NEXT: [[RES:%.*]] = fmul double [[TAN]], [[COS]]
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call double @llvm.tan.f64(double %a)
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%cos = call double @llvm.cos.f64(double %a)
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%res = fmul double %tan, %cos
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ret double %res
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}
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define double @fmul_strict_tan_strict_cos_contract(double %a) {
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; CHECK-LABEL: define double @fmul_strict_tan_strict_cos_contract(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[TAN:%.*]] = call double @llvm.tan.f64(double [[A]])
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; CHECK-NEXT: [[COS:%.*]] = call contract double @llvm.cos.f64(double [[A]])
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; CHECK-NEXT: [[RES:%.*]] = fmul double [[TAN]], [[COS]]
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call double @llvm.tan.f64(double %a)
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%cos = call contract double @llvm.cos.f64(double %a)
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%res = fmul double %tan, %cos
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ret double %res
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}
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define double @fmul_contract_tan_strict_cos_strict(double %a) {
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; CHECK-LABEL: define double @fmul_contract_tan_strict_cos_strict(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call double @llvm.tan.f64(double %a)
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%cos = call double @llvm.cos.f64(double %a)
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%res = fmul contract double %tan, %cos
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ret double %res
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}
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define double @fmul_contract_tan_contract_cos_strict(double %a) {
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; CHECK-LABEL: define double @fmul_contract_tan_contract_cos_strict(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call contract double @llvm.tan.f64(double %a)
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%cos = call double @llvm.cos.f64(double %a)
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%res = fmul contract double %tan, %cos
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ret double %res
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}
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define double @fmul_tan_cos_contract_multiple_uses(double %a) {
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; CHECK-LABEL: define double @fmul_tan_cos_contract_multiple_uses(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[TAN:%.*]] = call contract double @llvm.tan.f64(double [[A]])
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; CHECK-NEXT: [[COS:%.*]] = call contract double @llvm.cos.f64(double [[A]])
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; CHECK-NEXT: [[RES:%.*]] = fmul contract double [[TAN]], [[COS]]
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; CHECK-NEXT: call void @use(double [[COS]])
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call contract double @llvm.tan.f64(double %a)
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%cos = call contract double @llvm.cos.f64(double %a)
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%res = fmul contract double %tan, %cos
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call void @use(double %cos)
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ret double %res
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}
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define double @fmul_tan_cos_contract(double %a) {
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; CHECK-LABEL: define double @fmul_tan_cos_contract(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call contract double @llvm.tan.f64(double %a)
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%cos = call contract double @llvm.cos.f64(double %a)
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%res = fmul contract double %tan, %cos
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ret double %res
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}
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define float @fmul_tanf_cosf_contract(float %a) {
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; CHECK-LABEL: define float @fmul_tanf_cosf_contract(
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; CHECK-SAME: float [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract float @llvm.sin.f32(float [[A]])
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; CHECK-NEXT: ret float [[RES]]
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;
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%tan = call contract float @llvm.tan.f32(float %a)
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%cos = call contract float @llvm.cos.f32(float %a)
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%res = fmul contract float %tan, %cos
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ret float %res
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}
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define fp128 @fmul_tanfp128_cosfp128_contract(fp128 %a) {
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; CHECK-LABEL: define fp128 @fmul_tanfp128_cosfp128_contract(
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; CHECK-SAME: fp128 [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract fp128 @llvm.sin.f128(fp128 [[A]])
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; CHECK-NEXT: ret fp128 [[RES]]
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;
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%tan = call contract fp128 @llvm.tan.fp128(fp128 %a)
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%cos = call contract fp128 @llvm.cos.fp128(fp128 %a)
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%res = fmul contract fp128 %tan, %cos
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ret fp128 %res
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}
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define double @commutativity_cos_tan(double %a) {
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; CHECK-LABEL: define double @commutativity_cos_tan(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
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; CHECK-NEXT: ret double [[RES]]
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;
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%cos = call contract double @llvm.cos.f64(double %a)
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%tan = call contract double @llvm.tan.f64(double %a)
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%res = fmul contract double %cos, %tan
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ret double %res
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}
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define double @tan_cos_value_mismatch(double %a, double %b) {
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; CHECK-LABEL: define double @tan_cos_value_mismatch(
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; CHECK-SAME: double [[A:%.*]], double [[B:%.*]]) {
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; CHECK-NEXT: [[TAN:%.*]] = call contract double @llvm.tan.f64(double [[A]])
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; CHECK-NEXT: [[COS:%.*]] = call contract double @llvm.cos.f64(double [[B]])
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; CHECK-NEXT: [[RES:%.*]] = fmul contract double [[TAN]], [[COS]]
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call contract double @llvm.tan.f64(double %a)
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%cos = call contract double @llvm.cos.f64(double %b)
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%res = fmul contract double %tan, %cos
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ret double %res
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}
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define <2 x double> @fmul_tan_cos_vector(<2 x double> %a) {
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; CHECK-LABEL: define <2 x double> @fmul_tan_cos_vector(
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; CHECK-SAME: <2 x double> [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract <2 x double> @llvm.sin.v2f64(<2 x double> [[A]])
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; CHECK-NEXT: ret <2 x double> [[RES]]
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;
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%tan = call contract <2 x double> @llvm.tan.v2f64(<2 x double> %a)
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%cos = call contract <2 x double> @llvm.cos.v2f64(<2 x double> %a)
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%res = fmul contract <2 x double> %tan, %cos
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ret <2 x double> %res
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}
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define double @fmul_tan_cos_nnan_preservation(double %a) {
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; CHECK-LABEL: define double @fmul_tan_cos_nnan_preservation(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call nnan contract double @llvm.sin.f64(double [[A]])
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call contract double @llvm.tan.f64(double %a)
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%cos = call contract double @llvm.cos.f64(double %a)
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%res = fmul contract nnan double %tan, %cos
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ret double %res
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}
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define double @fmul_tan_cos_fpmath_metadata_preservation(double %a) {
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; CHECK-LABEL: define double @fmul_tan_cos_fpmath_metadata_preservation(
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; CHECK-SAME: double [[A:%.*]]) {
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; CHECK-NEXT: [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]]), !fpmath [[META0:![0-9]+]]
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; CHECK-NEXT: ret double [[RES]]
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;
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%tan = call contract double @llvm.tan.f64(double %a)
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%cos = call contract double @llvm.cos.f64(double %a)
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%res = fmul contract double %tan, %cos, !fpmath !0
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ret double %res
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}
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declare void @use(double)
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!0 = !{ float 2.5 }
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;.
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; CHECK: [[META0]] = !{float 2.500000e+00}
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;.

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