[Bug target/104610] memcmp () == 0 can be optimized better for avx512f

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104610

--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #3)
> (In reply to Hongtao.liu from comment #2)
> > in Gimple, there're
> > 
> >   _1 = __builtin_memcmp_eq (a_5(D), &t[0], 32);
> >   _2 = _1 == 0;
> >   _6 = (int) _2;
> > 
> > 
> > So it's related to codegen optimization with vectorized codes for
> > __builtin_memcmp_eq, guess we can start with size multiple of 16 bytes?
> > 
> There's no optab or target_hook for backend to participate in optimization
> of Participation in optimization.
typo last optimization should be compare_by_pieces.