[PATCH] x86: Update Intel Atom processor family optimization

[H.J. Lu]

On Sat, May 16, 2020 at 7:08 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Enable Intel Silvermont optimization for Intel Goldmont Plus.  Detect more
> Intel Airmont processors.  Optimize Intel Tremont like Intel Silvermont
> with rep string instructions.
> ---
>  sysdeps/x86/cpu-features.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
> index bfb415f05a..b1e4c2d1aa 100644
> --- a/sysdeps/x86/cpu-features.c
> +++ b/sysdeps/x86/cpu-features.c
> @@ -348,18 +348,23 @@ init_cpu_features (struct cpu_features *cpu_features)
>             case 0x57:
>               /* Knights Landing.  Enable Silvermont optimizations.  */
>
> +           case 0x7a:
> +             /* Unaligned load versions are faster than SSSE3
> +                on Goldmont Plus.  */
> +
>             case 0x5c:
>             case 0x5f:
>               /* Unaligned load versions are faster than SSSE3
>                  on Goldmont.  */
>
>             case 0x4c:
> +           case 0x5a:
> +           case 0x75:
>               /* Airmont is a die shrink of Silvermont.  */
>
>             case 0x37:
>             case 0x4a:
>             case 0x4d:
> -           case 0x5a:
>             case 0x5d:
>               /* Unaligned load versions are faster than SSSE3
>                  on Silvermont.  */
> @@ -370,6 +375,19 @@ init_cpu_features (struct cpu_features *cpu_features)
>                     | bit_arch_Slow_SSE4_2);
>               break;
>
> +           case 0x86:
> +           case 0x96:
> +           case 0x9c:
> +             /* Enable rep string instructions, unaligned load, unaligned
> +                copy, pminub and avoid SSE 4.2 on Tremont.  */
> +             cpu_features->feature[index_arch_Fast_Rep_String]
> +               |= (bit_arch_Fast_Rep_String
> +                   | bit_arch_Fast_Unaligned_Load
> +                   | bit_arch_Fast_Unaligned_Copy
> +                   | bit_arch_Prefer_PMINUB_for_stringop
> +                   | bit_arch_Slow_SSE4_2);
> +             break;
> +
>             default:
>               /* Unknown family 0x06 processors.  Assuming this is one
>                  of Core i3/i5/i7 processors if AVX is available.  */
> --
> 2.26.2
>

I am checking it in.

-- 
H.J.