[speex-dev] Performance increase?

Steve Kann stevek at stevek.com
Tue Apr 20 06:31:15 PDT 2004



Segher Boessenkool wrote:

>> I noticed that you changed all constant floating point numbers
>> from double notation (e.g. 3.0) to float notation (3.0f) in the latest
>> version
>> of Speex (in subversion).
>> Did that give any performance increase (because of elimination of the
>> float to double and double to float conversions)?
>
>
> It does, with some compilers.  Not doing it also (erroneously) gives
> errors with some compilers.

<p>It was based on my observations that using a gcc compiler flag to force 
floating point constants to be single-precision helped performance in a 
measurable way.  This has the same effect without special flags on all 
compilers.

-SteveK

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