Re: [PATCH v2 3/4] libav.inc: duplicate armv7a over-rides for armv7ve

Khem Raj
2016-01-12T16:26:48Z

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> On Jan 12, 2016, at 1:42 AM, Phil Blundell <pb@pbcl.net> wrote:
>
> On Mon, 2016-01-11 at 14:58 -0800, Khem Raj wrote:
>> it came into ffmpeg circa 2008 and proliferated into related components primarily to support vectorization and neon
>> which was quite nascent for ARM architecture in those days in gcc. Today if you were to configure libav with default options
>> then it uses mainly -fomit-frame-pointer-O3 -fno-math-errno -fno-signed-zeros -fno-tree-vectorize
>>
>> which is primarily -Ofast -fno-tree-vectorize
>
> I think -fno-tree-vectorize is just there as a workaround for old
> compilers. It sounds like you're saying that ffmpeg basically just
> wants "-Ofast", and by implication it wants this on all architectures.
> So in that case there is no need for a FULL_OPTIMIZATION override on
> arm, let alone armv7a specifically.

yes I think it should use -Ofast irrespective of architecture.

>
> Whether ffmpeg ought to be forcing its own FULL_OPTIMIZATION at all
> versus leaving it up to the distro is another question. Personally I
> think that individual recipes have no business setting those variables,
> and ffmpeg is no exception, but I don't have a particularly strong
> opinion either way.
>
> p.
>
>

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