Index: include/clang/Basic/BuiltinsX86.def
===================================================================
--- include/clang/Basic/BuiltinsX86.def
+++ include/clang/Basic/BuiltinsX86.def
@@ -652,6 +652,9 @@
 TARGET_BUILTIN(__builtin_ia32_xsaves, "vv*ULLi", "", "xsaves")
 TARGET_BUILTIN(__builtin_ia32_xsaves64, "vv*ULLi", "", "xsaves")
 
+//CLFLUSHOPT
+TARGET_BUILTIN(__builtin_ia32_clflushopt, "vc*", "", "clflushopt")
+
 // ADX
 TARGET_BUILTIN(__builtin_ia32_addcarryx_u32, "UcUcUiUiUi*", "", "adx")
 TARGET_BUILTIN(__builtin_ia32_addcarryx_u64, "UcUcULLiULLiULLi*", "", "adx")
Index: lib/Headers/CMakeLists.txt
===================================================================
--- lib/Headers/CMakeLists.txt
+++ lib/Headers/CMakeLists.txt
@@ -27,6 +27,7 @@
   __clang_cuda_runtime_wrapper.h
   cpuid.h
   cuda_builtin_vars.h
+  clflushoptintrin.h
   emmintrin.h
   f16cintrin.h
   float.h
Index: lib/Headers/clflushoptintrin.h
===================================================================
--- lib/Headers/clflushoptintrin.h
+++ lib/Headers/clflushoptintrin.h
@@ -0,0 +1,41 @@
+/*===---- clflushoptintrin.h - CLFLUSHOPT intrinsic ------------------------------------===
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __IMMINTRIN_H
+#error "Never use <clflushoptintrin.h> directly; include <immintrin.h> instead."
+#endif
+
+#ifndef __CLFLUSHOPTINTRIN_H
+#define __CLFLUSHOPTINTRIN_H
+
+/* Define the default attributes for the functions in this file. */
+#define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__,  __target__("clflushopt")))
+
+static __inline__ void __DEFAULT_FN_ATTRS
+_mm_clflushopt(char * __m) {
+  __builtin_ia32_clflushopt(__m);
+}
+
+#undef __DEFAULT_FN_ATTRS
+
+#endif
Index: lib/Headers/immintrin.h
===================================================================
--- lib/Headers/immintrin.h
+++ lib/Headers/immintrin.h
@@ -54,6 +54,10 @@
 #include <wmmintrin.h>
 #endif
 
+#if !defined(_MSC_VER) || __has_feature(modules) || defined(__CLFLUSHOPT__)
+#include <clflushoptintrin.h>
+#endif
+
 #if !defined(_MSC_VER) || __has_feature(modules) || defined(__AVX__)
 #include <avxintrin.h>
 #endif
Index: test/CodeGen/builtin-clflushopt.c
===================================================================
--- test/CodeGen/builtin-clflushopt.c
+++ test/CodeGen/builtin-clflushopt.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin -target-feature +clflushopt  -emit-llvm -o - -Werror | FileCheck %s
+#define __MM_MALLOC_H
+
+#include <immintrin.h>
+void test_mm_clflushopt(char * __m) {
+  //CHECK-LABLE: @test_mm_clflushopt
+  //CHECK: @llvm.x86.clflushopt
+  _mm_clflushopt(__m);
+}