https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113025
Xi Ruoyao <xry111 at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |xry111 at gcc dot gnu.org
--- Comment #3 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to juki from comment #2)
> Unfortunately alignment of the cast type was not causing this issue.
>
> I changed all calls that were defined in GCC headers to use __m128i_u or
> __m128d_u types to use those types before unaligned intrinsic.
>
> For example LOAD_SI128 macro looks like the following:
>
> #define LOAD_SI128(ptr) \
> ( ((uintptr_t)(ptr) & 15) == 0 ) ? _mm_load_si128((__m128i*)(ptr)) :
> _mm_loadu_si128((__m128i_u*)(ptr))
This won't work if ptr is a __m128i *. It is allowed to optimize
(uintptr_t)(__m128i *)foo % 15 to 0 because the standard says (__m128i *)foo
invokes undefined behavior when foo is a pointer not aligned to 16-byte
boundary (C23 section 6.3.2.3p6).
