Add 'may_alias' attribute. Noticed by Eli.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131278 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Headers/emmintrin.h

@@ -468,7 +468,7 @@ _mm_loadu_pd(double const *dp)
 {
   struct __loadu_pd {
     __m128d v;
-  } __attribute__((packed));
+  } __attribute__((packed, may_alias));
   return ((struct __loadu_pd*)dp)->v;
 }
 
@@ -1016,7 +1016,7 @@ _mm_loadu_si128(__m128i const *p)
 {
   struct __loadu_si128 {
     __m128i v;
-  } __attribute__((packed));
+  } __attribute__((packed, may_alias));
   return ((struct __loadu_si128*)p)->v;
 }
 

lib/Headers/xmmintrin.h

@@ -541,7 +541,7 @@ _mm_loadu_ps(const float *p)
 {
   struct __loadu_ps {
     __m128 v;
-  } __attribute__((packed));
+  } __attribute__((packed, may_alias));
   return ((struct __loadu_ps*)p)->v;
 }