Recommit r299321 '[X86] Add __extension__ to f16c macro intrinsics to suppress...

Recommit r299321 '[X86] Add __extension__ to f16c macro intrinsics to suppress warnings about compound literals when compiled for with earlier language standards enabled.'

The bot didn't recover after the revert. So it looks like this wasn't the issue.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@299397 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Headers/f16cintrin.h

@@ -72,9 +72,9 @@ _cvtsh_ss(unsigned short __a)
 ///    011: Truncate \n
 ///    1XX: Use MXCSR.RC for rounding
 /// \returns The converted 16-bit half-precision float value.
-#define _cvtss_sh(a, imm)  \
-  ((unsigned short)(((__v8hi)__builtin_ia32_vcvtps2ph((__v4sf){a, 0, 0, 0}, \
-                                                      (imm)))[0]))
+#define _cvtss_sh(a, imm) __extension__ ({ \
+  (unsigned short)(((__v8hi)__builtin_ia32_vcvtps2ph((__v4sf){a, 0, 0, 0}, \
+                                                     (imm)))[0]); })
 
 /// \brief Converts a 128-bit vector containing 32-bit float values into a
 ///    128-bit vector containing 16-bit half-precision float values.
@@ -99,8 +99,8 @@ _cvtsh_ss(unsigned short __a)
 /// \returns A 128-bit vector containing converted 16-bit half-precision float
 ///    values. The lower 64 bits are used to store the converted 16-bit
 ///    half-precision floating-point values.
-#define _mm_cvtps_ph(a, imm) \
-  ((__m128i)__builtin_ia32_vcvtps2ph((__v4sf)(__m128)(a), (imm)))
+#define _mm_cvtps_ph(a, imm) __extension__ ({ \
+  (__m128i)__builtin_ia32_vcvtps2ph((__v4sf)(__m128)(a), (imm)); })
 
 /// \brief Converts a 128-bit vector containing 16-bit half-precision float
 ///    values into a 128-bit vector containing 32-bit float values.