[FFmpeg-devel] -fsingle-precision-constant

Måns Rullgård mans
Thu May 13 22:33:54 CEST 2010


Jason Garrett-Glaser <darkshikari at gmail.com> writes:

>> does C really mandate the implementation to use double precision?
>> i mean it can mandate the high level type be double but what is
>> preventing the compiler from using a very slightly lower precission
>> float implemenattion.
>> i ve heared intels c compiler will even use trigonometric identities
>> to optimize float code ...
>
> That's what -ffast-math is for.

Note that we cannot use -ffast-math in FFmpeg.  It enables
-ffinite-math-only, which might make things fail if NaNs or
infinities are used, and we use both.

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



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