On Thu, 2006-04-27 at 18:42 +0200, Rudi Chiarito wrote:
More in general, though, isn't a call to sin() and cos()
expensive and
shouldn't the compiler just use inline native FP code? In the case of
FFTW those two are only used in the setup stages, with the actual FFTs
implemented with multiplications and additions (gcc uses SSE as
expected on x86_64), but not all code is going to be like that. Are
there reasons for them not to be inlined?
Isn't this what --ffast-math does?
Some gritty details seem to be here:
http://gcc.gnu.org/wiki/Math%20Optimization%20Flags
gcc is far smarter than many seem to realize. Sometimes far too smart...