Hi!
The x86 __m64 type is defined as:
/* The Intel API is flexible enough that we must allow aliasing with other
vector types, and their scalar components. */
typedef int __m64 __attribute__ ((__vector_size__ (8), __may_alias__));
and so matches the comment above it in that reads and stores through
pointers to __m64 can alias anything.
But in the rs6000 headers that is the case only for __m128, but not __m64.
The following patch adds that attribute, which fixes the
FAIL: gcc.target/powerpc/sse-movhps-1.c execution test
FAIL: gcc.target/powerpc/sse-movlps-1.c execution test
regressions that appeared when Honza improved ipa-modref.
Bootstrapped/regtested on powerpc64le-linux and powerpc64-linux (the latter
with -m32/-m64 testing), ok for trunk?
2021-01-22 Jakub Jelinek <ja...@redhat.com>
PR testsuite/97301
* config/rs6000/mmintrin.h (__m64): Add __may_alias__ attribute.
--- gcc/config/rs6000/mmintrin.h.jj 2021-01-04 10:25:46.794143679 +0100
+++ gcc/config/rs6000/mmintrin.h 2021-01-22 13:03:28.511043929 +0100
@@ -58,7 +58,8 @@
#include <altivec.h>
/* The Intel API is flexible enough that we must allow aliasing with other
vector types, and their scalar components. */
-typedef __attribute__ ((__aligned__ (8))) unsigned long long __m64;
+typedef __attribute__ ((__aligned__ (8),
+ __may_alias__)) unsigned long long __m64;
typedef __attribute__ ((__aligned__ (8)))
union
Jakub
