On Wed, Jan 27, 2016 at 8:11 AM, Ilya Enkovich <enkovich....@gmail.com> wrote:
> On 27 Jan 16:44, Jakub Jelinek wrote:
>> On Wed, Jan 27, 2016 at 06:34:41PM +0300, Ilya Enkovich wrote:
>> > @@ -5453,6 +5443,11 @@ ix86_option_override_internal (bool main_args_p,
>> > opts->x_target_flags |= MASK_VZEROUPPER;
>> > if (!(opts_set->x_target_flags & MASK_STV))
>> > opts->x_target_flags |= MASK_STV;
>> > + /* Disable STV if -mpreferred-stack-boundary={2,3} - the needed
>>
>> The comment doesn't match the code, you disable STV only for
>> -mpreferred-stack-boundary=2.
>
> Thanks, here is an updated version.
>
> Ilya
> --
> gcc/
>
> 2016-01-27 Jakub Jelinek <ja...@redhat.com>
> Ilya Enkovich <enkovich....@gmail.com>
>
> PR target/69454
> * config/i386/i386.c (convert_scalars_to_vector): Remove
> stack alignment fixes.
> (ix86_option_override_internal): Disable TARGET_STV if stack
> is not properly aligned.
>
> gcc/testsuite/
>
> 2016-01-27 Ilya Enkovich <enkovich....@gmail.com>
>
> PR target/69454
> * gcc.target/i386/pr69454-1.c: New test.
> * gcc.target/i386/pr69454-2.c: New test.
>
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 34b57a4..9fb8db8 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -3588,16 +3588,6 @@ convert_scalars_to_vector ()
> bitmap_obstack_release (NULL);
> df_process_deferred_rescans ();
>
> - /* Conversion means we may have 128bit register spills/fills
> - which require aligned stack. */
> - if (converted_insns)
> - {
> - if (crtl->stack_alignment_needed < 128)
> - crtl->stack_alignment_needed = 128;
> - if (crtl->stack_alignment_estimated < 128)
> - crtl->stack_alignment_estimated = 128;
> - }
> -
> return 0;
> }
>
> @@ -5453,6 +5443,11 @@ ix86_option_override_internal (bool main_args_p,
> opts->x_target_flags |= MASK_VZEROUPPER;
> if (!(opts_set->x_target_flags & MASK_STV))
> opts->x_target_flags |= MASK_STV;
> + /* Disable STV if -mpreferred-stack-boundary=2 - the needed
> + stack realignment will be extra cost the pass doesn't take into
> + account and the pass can't realign the stack. */
> + if (ix86_preferred_stack_boundary < 64)
> + opts->x_target_flags &= ~MASK_STV;
> if (!ix86_tune_features[X86_TUNE_AVX256_UNALIGNED_LOAD_OPTIMAL]
> && !(opts_set->x_target_flags & MASK_AVX256_SPLIT_UNALIGNED_LOAD))
> opts->x_target_flags |= MASK_AVX256_SPLIT_UNALIGNED_LOAD;
MINIMUM_ALIGNMENT keeps track stack alignment. It is OK
to disable STV for -mpreferred-stack-boundary=2. But you should
also update ix86_minimum_alignment to make sure that STV is
disabled before returning 32 for DImode.
--
H.J.
