https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78853
--- Comment #3 from Pedro Gonnet <gonnet at google dot com> --- OK, thanks for clarifying! The declaration of __m256i only specifies the attributes vector_size and may_alias (https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/i386/avxintrin.h;hb=HEAD#l56), so I'm guessing vector_size implies alignment? This does not seem to be documented anywhere obvious. Also interesting is that icc-17 produces unaligned load/stores for the same code, but there is no amount of __attribute__((aligned(32))) that will make them aligned. In any case I'll use the __m*_u types to make an unaligned version of my memswap function.
