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NNTP-Posting-Date: Fri, 17 Mar 2017 00:07:06 -0500
From: Gareth Owen <gwowen@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: C Compilers QoI
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Date: Fri, 17 Mar 2017 05:07:06 +0000
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Ian Collins <ian-news@hotmail.com> writes:

> On 03/17/17 11:30 AM, Ian Collins wrote
>>
>> For computationally intensive (vectorisable)  code, such as FFmpeg, the
>> particulars of specific processors, especially supported SIMD
>> instructions can make a very significantly affect performance.
>>
> Need a grammar checker...
>
> For computationally intensive (vectorisable)  code such as FFmpeg the
> particulars of specific processors, especially supported SIMD
> instructions, can very significantly affect performance.

True, but for those purposes FFmpeg often falls back to using inline asm
or explicit __builtin_xxx SIMD instructions, which suggests the
optimisers have some way to on architecture-specific tuning - particular
in the presence of potential aliasing.