Re: [RFC] Combine vectorized loops with its scalar remainder.

[Richard Biener <richard dot guenther at gmail dot com>]

On Tue, Nov 10, 2015 at 2:02 PM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
> 2015-11-10 15:30 GMT+03:00 Richard Biener <richard.guenther@gmail.com>:
>> On Tue, Nov 3, 2015 at 1:08 PM, Yuri Rumyantsev <ysrumyan@gmail.com> wrote:
>>> Richard,
>>>
>>> It looks like misunderstanding - we assume that for GCCv6 the simple
>>> scheme of remainder will be used through introducing new IV :
>>> https://gcc.gnu.org/ml/gcc-patches/2015-09/msg01435.html
>>>
>>> Is it true or we missed something?
>>
>> <quote>
>>> > Do you have an idea how "masking" is better be organized to be usable
>>> > for both 4b and 4c?
>>>
>>> Do 2a ...
>> Okay.
>> </quote>
>
> 2a was 'transform already vectorized loop as a separate
> post-processing'. Isn't it what this prototype patch implements?
> Current version only masks loop body which is in practice applicable
> for AVX-512 only in the most cases.  With AVX-512 it's easier to see
> how profitable masking might be and it is a main target for the first
> masking version.  Extending it to prologues/epilogues and thus making
> it more profitable for other targets is the next step and is out of
> the scope of this patch.

Ok, technically the prototype transforms the already vectorized loop.
Of course I meant the vectorized loop be copied, masked and that
result used as epilogue...

I'll queue a more detailed look into the patch for this week.

Did you perform any measurements with this patch like # of
masked epilogues in SPEC 2006 FP (and any speedup?)

Thanks,
Richard.

> Thanks,
> Ilya
>
>>
>> Richard.
>>