Comment mystery code.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149742 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/Headers/emmintrin.h b/lib/Headers/emmintrin.h
index 3453b4ae25..e10b77d1b2 100644
--- a/lib/Headers/emmintrin.h
+++ b/lib/Headers/emmintrin.h
@@ -947,6 +947,8 @@ _mm_cmpeq_epi32(__m128i a, __m128i b)
 static __inline__ __m128i __attribute__((__always_inline__, __nodebug__))
 _mm_cmpgt_epi8(__m128i a, __m128i b)
 {
+  /* This function always performs a signed comparison, but __v16qi is a char
+     which may be signed or unsigned. */
   typedef signed char __v16qs __attribute__((__vector_size__(16)));
   return (__m128i)((__v16qs)a > (__v16qs)b);
 }