2016-01-27 19:18 GMT+03:00 H.J. Lu <hjl.to...@gmail.com>:
> 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.
If -mpreferred-stack-boundary=2 then STV is disabled, if STV is enabled then
-mpreferred-stack-boundary>=3 and this condition in
ix86_minimum_alignment works:
if (TARGET_64BIT || align != 64 || ix86_preferred_stack_boundary >= 64)
return align;
Thanks,
Ilya
>
>
> --
> H.J.
