diff --git a/clang/include/clang/Basic/BuiltinsAArch64.def b/clang/include/clang/Basic/BuiltinsAArch64.def
--- a/clang/include/clang/Basic/BuiltinsAArch64.def
+++ b/clang/include/clang/Basic/BuiltinsAArch64.def
@@ -243,6 +243,9 @@
 TARGET_HEADER_BUILTIN(_WriteStatusReg, "viLLi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_AddressOfReturnAddress, "v*", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 
+TARGET_HEADER_BUILTIN(__mulh,  "SLLiSLLiSLLi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
+TARGET_HEADER_BUILTIN(__umulh, "ULLiULLiULLi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
+
 #undef BUILTIN
 #undef LANGBUILTIN
 #undef TARGET_HEADER_BUILTIN
diff --git a/clang/lib/Headers/intrin.h b/clang/lib/Headers/intrin.h
--- a/clang/lib/Headers/intrin.h
+++ b/clang/lib/Headers/intrin.h
@@ -574,6 +574,9 @@
 unsigned short __cdecl _byteswap_ushort(unsigned short val);
 unsigned long __cdecl _byteswap_ulong (unsigned long val);
 unsigned __int64 __cdecl _byteswap_uint64(unsigned __int64 val);
+
+__int64 __mulh(__int64 __a, __int64 __b);
+unsigned __int64 __umulh(unsigned __int64 __a, unsigned __int64 __b);
 #endif
 
 /*----------------------------------------------------------------------------*\
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -81,6 +81,20 @@
 // CHECK-MSVC: fence syncscope("singlethread")
 // CHECK-LINUX: error: implicit declaration of function '_ReadWriteBarrier'
 
+long long check_mulh(long long a, long long b) {
+  return __mulh(a, b);
+}
+
+// CHECK-MSVC: call i64 @llvm.aarch64.smulh(i64 %[[PARAM1:.*]], i64 %[[PARAM2:.*]])
+// CHECK-LINUX: error: implicit declaration of function '__mulh'
+
+unsigned long long check_umulh(unsigned long long a, unsigned long long b) {
+  return __umulh(a, b);
+}
+
+// CHECK-MSVC: call i64 @llvm.aarch64.umulh(i64 %[[PARAM3:.*]], i64 %[[PARAM4:.*]])
+// CHECK-LINUX: error: implicit declaration of function '__umulh'
+
 unsigned __int64 check__getReg() {
   unsigned volatile __int64 reg;
   reg = __getReg(18);
diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -34,6 +34,13 @@
 
 def int_aarch64_clrex : Intrinsic<[]>;
 
+def int_aarch64_smulh : MSBuiltin<"__mulh">,
+                      Intrinsic<[llvm_i64_ty], [llvm_i64_ty, llvm_i64_ty],
+                                [IntrNoMem, IntrWillReturn]>;
+def int_aarch64_umulh : MSBuiltin<"__umulh">,
+                      Intrinsic<[llvm_i64_ty], [llvm_i64_ty, llvm_i64_ty],
+                                [IntrNoMem, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -1709,6 +1709,8 @@
 // Multiply-high
 def SMULHrr : MulHi<0b010, "smulh", mulhs>;
 def UMULHrr : MulHi<0b110, "umulh", mulhu>;
+def : Pat<(int_aarch64_smulh GPR64:$Rn, GPR64:$Rm), (SMULHrr GPR64:$Rn, GPR64:$Rm)>;
+def : Pat<(int_aarch64_umulh GPR64:$Rn, GPR64:$Rm), (UMULHrr GPR64:$Rn, GPR64:$Rm)>;
 
 // CRC32
 def CRC32Brr : BaseCRC32<0, 0b00, 0, GPR32, int_aarch64_crc32b, "crc32b">;
diff --git a/llvm/test/CodeGen/AArch64/intrinsics-mulh.ll b/llvm/test/CodeGen/AArch64/intrinsics-mulh.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/intrinsics-mulh.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s -mtriple=aarch64-eabi -O=3 | FileCheck %s
+
+
+define i64 @check_smulh(i64 %a, i64 %b) {
+entry:
+  ; CHECK: smulh x0, x0, x1
+  %0 = tail call i64 @llvm.aarch64.smulh(i64 %a, i64 %b)
+  ret i64 %0
+} 
+
+define i64 @check_umulh(i64 %a, i64 %b) {
+entry:
+  ; CHECK: umulh x0, x0, x1
+  %0 = tail call i64 @llvm.aarch64.umulh(i64 %a, i64 %b)
+  ret i64 %0
+} 
+
+
+declare i64 @llvm.aarch64.smulh(i64, i64)
+declare i64 @llvm.aarch64.umulh(i64, i64)
+