diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index c7023eb79b04e..8ffbdef61b6fa 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -1073,6 +1073,18 @@ Instruction *InstCombinerImpl::visitFMul(BinaryOperator &I) {
     return Result;
   }
 
+  // tan(X) * cos(X) -> sin(X)
+  if (I.hasAllowContract() &&
+      match(&I,
+            m_c_FMul(m_OneUse(m_Intrinsic<Intrinsic::tan>(m_Value(X))),
+                     m_OneUse(m_Intrinsic<Intrinsic::cos>(m_Deferred(X)))))) {
+    auto *Sin = Builder.CreateUnaryIntrinsic(Intrinsic::sin, X, &I);
+    if (auto *Metadata = I.getMetadata(LLVMContext::MD_fpmath)) {
+      Sin->setMetadata(LLVMContext::MD_fpmath, Metadata);
+    }
+    return replaceInstUsesWith(I, Sin);
+  }
+
   return nullptr;
 }
 
diff --git a/llvm/test/Transforms/InstCombine/fmul-tan-cos.ll b/llvm/test/Transforms/InstCombine/fmul-tan-cos.ll
new file mode 100644
index 0000000000000..c3446948542e8
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/fmul-tan-cos.ll
@@ -0,0 +1,180 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=instcombine < %s | FileCheck %s
+
+define double @fmul_tan_cos(double %a) {
+; CHECK-LABEL: define double @fmul_tan_cos(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[TAN:%.*]] = call double @llvm.tan.f64(double [[A]])
+; CHECK-NEXT:    [[COS:%.*]] = call double @llvm.cos.f64(double [[A]])
+; CHECK-NEXT:    [[RES:%.*]] = fmul double [[TAN]], [[COS]]
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call double @llvm.tan.f64(double %a)
+  %cos = call double @llvm.cos.f64(double %a)
+  %res = fmul double %tan, %cos
+  ret double %res
+}
+
+define double @fmul_strict_tan_strict_cos_contract(double %a) {
+; CHECK-LABEL: define double @fmul_strict_tan_strict_cos_contract(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[TAN:%.*]] = call double @llvm.tan.f64(double [[A]])
+; CHECK-NEXT:    [[COS:%.*]] = call contract double @llvm.cos.f64(double [[A]])
+; CHECK-NEXT:    [[RES:%.*]] = fmul double [[TAN]], [[COS]]
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call double @llvm.tan.f64(double %a)
+  %cos = call contract double @llvm.cos.f64(double %a)
+  %res = fmul double %tan, %cos
+  ret double %res
+}
+
+define double @fmul_contract_tan_strict_cos_strict(double %a) {
+; CHECK-LABEL: define double @fmul_contract_tan_strict_cos_strict(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call double @llvm.tan.f64(double %a)
+  %cos = call double @llvm.cos.f64(double %a)
+  %res = fmul contract double %tan, %cos
+  ret double %res
+}
+
+define double @fmul_contract_tan_contract_cos_strict(double %a) {
+; CHECK-LABEL: define double @fmul_contract_tan_contract_cos_strict(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %cos = call double @llvm.cos.f64(double %a)
+  %res = fmul contract double %tan, %cos
+  ret double %res
+}
+
+define double @fmul_tan_cos_contract_multiple_uses(double %a) {
+; CHECK-LABEL: define double @fmul_tan_cos_contract_multiple_uses(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[TAN:%.*]] = call contract double @llvm.tan.f64(double [[A]])
+; CHECK-NEXT:    [[COS:%.*]] = call contract double @llvm.cos.f64(double [[A]])
+; CHECK-NEXT:    [[RES:%.*]] = fmul contract double [[TAN]], [[COS]]
+; CHECK-NEXT:    call void @use(double [[COS]])
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %cos = call contract double @llvm.cos.f64(double %a)
+  %res = fmul contract double %tan, %cos
+  call void @use(double %cos)
+  ret double %res
+}
+
+define double @fmul_tan_cos_contract(double %a) {
+; CHECK-LABEL: define double @fmul_tan_cos_contract(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %cos = call contract double @llvm.cos.f64(double %a)
+  %res = fmul contract double %tan, %cos
+  ret double %res
+}
+
+define float @fmul_tanf_cosf_contract(float %a) {
+; CHECK-LABEL: define float @fmul_tanf_cosf_contract(
+; CHECK-SAME: float [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract float @llvm.sin.f32(float [[A]])
+; CHECK-NEXT:    ret float [[RES]]
+;
+  %tan = call contract float @llvm.tan.f32(float %a)
+  %cos = call contract float @llvm.cos.f32(float %a)
+  %res = fmul contract float %tan, %cos
+  ret float %res
+}
+
+define fp128 @fmul_tanfp128_cosfp128_contract(fp128 %a) {
+; CHECK-LABEL: define fp128 @fmul_tanfp128_cosfp128_contract(
+; CHECK-SAME: fp128 [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract fp128 @llvm.sin.f128(fp128 [[A]])
+; CHECK-NEXT:    ret fp128 [[RES]]
+;
+  %tan = call contract fp128 @llvm.tan.fp128(fp128 %a)
+  %cos = call contract fp128 @llvm.cos.fp128(fp128 %a)
+  %res = fmul contract fp128 %tan, %cos
+  ret fp128 %res
+}
+
+; commutativity
+define double @commutativity_cos_tan(double %a) {
+; CHECK-LABEL: define double @commutativity_cos_tan(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]])
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %cos = call contract double @llvm.cos.f64(double %a)
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %res = fmul contract double %cos, %tan
+  ret double %res
+}
+
+; negative test with mismatched value
+define double @tan_cos_value_mismatch(double %a, double %b) {
+; CHECK-LABEL: define double @tan_cos_value_mismatch(
+; CHECK-SAME: double [[A:%.*]], double [[B:%.*]]) {
+; CHECK-NEXT:    [[TAN:%.*]] = call contract double @llvm.tan.f64(double [[A]])
+; CHECK-NEXT:    [[COS:%.*]] = call contract double @llvm.cos.f64(double [[B]])
+; CHECK-NEXT:    [[RES:%.*]] = fmul contract double [[TAN]], [[COS]]
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %cos = call contract double @llvm.cos.f64(double %b)
+  %res = fmul contract double %tan, %cos
+  ret double %res
+}
+
+; Vector
+define <2 x double> @fmul_tan_cos_vector(<2 x double> %a) {
+; CHECK-LABEL: define <2 x double> @fmul_tan_cos_vector(
+; CHECK-SAME: <2 x double> [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract <2 x double> @llvm.sin.v2f64(<2 x double> [[A]])
+; CHECK-NEXT:    ret <2 x double> [[RES]]
+;
+  %tan = call contract <2 x double> @llvm.tan.v2f64(<2 x double> %a)
+  %cos = call contract <2 x double> @llvm.cos.v2f64(<2 x double> %a)
+  %res = fmul contract <2 x double> %tan, %cos
+  ret <2 x double> %res
+}
+
+; Flag preservation
+define double @fmul_tan_cos_nnan_preservation(double %a) {
+; CHECK-LABEL: define double @fmul_tan_cos_nnan_preservation(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call nnan contract double @llvm.sin.f64(double [[A]])
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %cos = call contract double @llvm.cos.f64(double %a)
+  %res = fmul contract nnan double %tan, %cos
+  ret double %res
+}
+
+; !fpmath metadata preservation
+define double @fmul_tan_cos_fpmath_metadata_preservation(double %a) {
+; CHECK-LABEL: define double @fmul_tan_cos_fpmath_metadata_preservation(
+; CHECK-SAME: double [[A:%.*]]) {
+; CHECK-NEXT:    [[RES:%.*]] = call contract double @llvm.sin.f64(double [[A]]), !fpmath [[META0:![0-9]+]]
+; CHECK-NEXT:    ret double [[RES]]
+;
+  %tan = call contract double @llvm.tan.f64(double %a)
+  %cos = call contract double @llvm.cos.f64(double %a)
+  %res = fmul contract double %tan, %cos, !fpmath !0
+  ret double %res
+}
+
+declare void @use(double)
+
+!0 = !{ float 2.5 }
+;.
+; CHECK: [[META0]] = !{float 2.500000e+00}
+;.