[Bug target/63791] use 32-byte version of vpbroadcastb (and register to poulate) on AVX/AVX2 platforms

[marcus.kool at urlfilterdb dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63791

--- Comment #4 from Marcus Kool <marcus.kool at urlfilterdb dot com> ---
>         movl    %edi, -12(%rsp)
>         vpxor   %xmm1, %xmm1, %xmm1
>         vmovd   -12(%rsp), %xmm0
>         xorl    %eax, %eax
>         vpshufb %xmm1, %xmm0, %xmm0

The xorl instruction is part of an other statement and is not part of the code
generated by _mm_set1_epi8().