[FFmpeg-devel] [PATCH 3/4] avcodec/mpegaudio_tablegen: more dynamic table creation speedups

[Ganesh Ajjanagadde]

On Sat, Nov 28, 2015 at 4:47 PM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
> On Sat, Nov 28, 2015 at 4:35 PM, Derek Buitenhuis
> <derek.buitenhuis at gmail.com> wrote:
>> On 11/28/2015 9:26 PM, Derek Buitenhuis wrote:
>>> Changing all of them sounds fine to me.
>>
>> [21:31] <@ubitux> re: i%4 vs i&3; you should ask him to make sure the compiler is smart enough regarding the signess of i
>
> No idea, actually GCC even to this day has issues with signed vs unsigned.
>
> Trivial example (unrelated),
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48052 which is still
> open. Lesson for FFmpeg - make sure looping is done with int i instead
> of unsigned i. I have not done an extensive audit, but FFmpeg seems
> mostly good in this respect.
>
> So I will follow Derek's suggestion and use i & 3 uniformly here; I
> lack the energy to investigate and will err on the safe side wrt
> performance.

pushed with the i & 3.

>
>>
>> - Derek
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