[FFmpeg-devel] [flamefest-start] A little something on MMX/SSE intrinsics

Måns Rullgård mans
Thu Feb 28 02:43:33 CET 2008


Rich Felker <dalias at aerifal.cx> writes:

> On Wed, Feb 27, 2008 at 10:59:52PM +0000, M?ns Rullg?rd wrote:
>> > I do know that gcc does quite stupid things on x86 be it when compiling C
>> > code or intrinsics. And i know that gcc is generally better at compiling
>> > x86 code than code for other less common architecures. Combining these
>> > does strongly point toward that the gap between intrinsics and asm will
>> > be bigger on ppc than x86 not smaller.
>> > Of course you are correct that i do not strictly "know" it. Its just VERY
>> > likely.
>> 
>> It is wrong to talk about the probability of something that has a
>> definite value, even if it has not yet been measured.  Probabilities
>> would be appropriate if speculating over the abilities of future GCC
>> versions.
>
> Welcome to the world of QM. Unfortunately that's how all facts are..

If the trend in gcc code size keeps up, they won't be in the QM domain
for quite some time to come.

-- 
M?ns Rullg?rd
mans at mansr.com




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