2 files changed, 67 insertions, 0 deletions
diff --git a/lib/Headers/CMakeLists.txt b/lib/Headers/CMakeLists.txt
index 78141a3d07..f8c0309b29 100644
--- a/lib/Headers/CMakeLists.txt
+++ b/lib/Headers/CMakeLists.txt
@@ -8,6 +8,7 @@ set(files
   float.h
   fma4intrin.h
   immintrin.h
+  intrin.h
   iso646.h
   limits.h
   lzcntintrin.h
diff --git a/lib/Headers/intrin.h b/lib/Headers/intrin.h
new file mode 100644
index 0000000000..b4a9aa6367
--- /dev/null
+++ b/lib/Headers/intrin.h
@@ -0,0 +1,66 @@
+/*===---- intrin.h - Microsoft VS compatible X86 intrinsics -----------------===
+ *
+ * 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.
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+/* Unless we're compiling targeting MSVC platform, this header shouldn't even
+ * *exist*. If there is a system header with the same name, defer to that,
+ * etherwise produce an error for the user.
+ */
+#ifndef _MSC_VER
+# if defined(__has_include_next) && __has_include_next(<intrin.h>)
+#  include_next <intrin.h>
+# else
+#  error The <intrin.h> builtin header is for use when targeting Windows and \
+         provides MSVC compatible intrinsic declarations. It shouldn't be used \
+         on non-Windows targets. Instead, see <x86intrin.h> which is supported \
+         by Clang, GCC, and ICC on all platforms.
+# endif
+#else /* _MSC_VER */
+
+#ifndef __INTRIN_H
+#define __INTRIN_H
+
+/* These headers need to be provided by intrin.h in case users depend on any of
+ * their contents. However, some of them are unavailable in freestanding
+ * builds, so guard them appropriately.
+ */
+#if __STDC_HOSTED__
+# include <crtdefs.h>
+# include <setjmp.h>
+#endif
+#include <stddef.h>
+
+/* Microsoft includes all of the intrinsics, and then restricts their
+ * availability based on the particular target CPU; with Clang te rely on the
+ * guarded includes used in our generic x86intrin header to pull in the
+ * intrinsic declarations / definitions which should be available for the
+ * target CPU variant.
+ */
+#include <x86intrin.h>
+
+/* FIXME: We need to provide declarations for Microsoft-specific intrinsics in
+ * addition to the chip-vendor intrinsics provided by x86intrin.h.
+ */
+
+#endif /* __INTRIN_H */
+
+#endif /* _MSC_VER */