[PATCH PR50572] Tune loop alignment for Atom

[Uros Bizjak]

On Wed, Oct 19, 2011 at 2:26 PM, Sergey Ostanevich <sergos.gnu@gmail.com> wrote:

>> You can just change the default in processor_target_table.
>>
>> Uros.
>>
>
> Will it be applicable during optimizations for size? It will hurt,
> although not much (see PR).

Looking at the code, I'd say that we don't handle -Os in different way.

> New patch is below. Ok for trunk as obvious?
>
> Sergos
>
> 2011-10-19  Sergey Ostanevich  <sergos.gnu@gmail.com>
>
>        * gcc/config/i386/i386.c (ix86_option_override_internal): use loop
>        align by 16 bytes for Atom platform

Please update ChangeLog, like:

* gcc/config/i386/i386.c (processor_target_table): Change Atom
align_loop_max_skip to 15.

> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 2c53423..8c60086 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -2596,7 +2596,7 @@ static const struct ptt
> processor_target_table[PROCESSOR_max] =
>   {&bdver1_cost, 32, 24, 32, 7, 32},
>   {&bdver2_cost, 32, 24, 32, 7, 32},
>   {&btver1_cost, 32, 24, 32, 7, 32},
> -  {&atom_cost, 16, 7, 16, 7, 16}
> +  {&atom_cost, 16, 15, 16, 7, 16}
>  };


OK.

Thanks,
Uros.