[PATCH] x86_64: memset optimized with AVX512

[Richard Henderson]

On 12/03/2015 12:46 PM, Andrew Senkevich wrote:
> +       .section .text,"ax",@progbits
> +ENTRY (MEMSET)
> +#ifdef HAVE_AVX512_ASM_SUPPORT

Surely you'd just wrap the entire function with this ifdef,
so that you don't produce the __memset_avx512 symbol at all.


> +       vpxor   %xmm0, %xmm0, %xmm0
> +       vmovd   %esi, %xmm1
...
> +       vpshufb %xmm0, %xmm1, %xmm0
...
> +       vbroadcastss    %xmm0, %zmm2

Surely vpbroadcastb %esi, %{x,z}mm2

Do you need a vzeroupper on the exit paths that use the zmm/ymm register?
We've got them in the avx2 memset...


r~