[Gegl-developer] Question about the use of C99/gcc built-in math intrinsics within GEGL on gfloats

[Nicolas Robidoux]

Hello Sven:

Thanks for your answer. Simplifies my life a lot.

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There is another C99/gcc built-in with the potential to speed up code a lot: the restrict keyword.

See:

http://www.cellperformance.com/mike_acton/2006/05/demystifying_the_restrict_keyw.html

I'll build two versions of the gegl-sampler-yafr code (one of which which I'll masquerade as gegl-sampler-cubic so I can run both without recompiling) and run careful benchmarks this weekend. One version will stay away from restrict and c99 math intrinsics, the other will not (first pass, I may not go as far as making explicit calls to fma, although my code is structured in the hope that the compiler recognizes fused multiply-adds when appropriate).

I don't quite understand the issues of writing c++ code using c99 features (this is why knowing that they are gcc built-ins is useful, provided one knows that gcc will be the compiler).

Maybe I'll inspire myself from

http://www.ddj.com/cpp/184401653

Nicolas Robidoux
Laurentian University/Universite Laurentienne