On 02/09/2012 10:20 AM, James Courtier-Dutton wrote: > From what I can see, on x86_64, the hardware fsin(x) is more accurate > than the hardware fsincos(x). > As you gradually increase the size of X from 0 to 10e22, fsincos(x) > diverges from the correct accurate value quicker than fsin(x) does. > > So, from this I would say that using fsincos instead of fsin is not a > good idea, at least on x86_64 platforms.
That's true iff you're using the hardware builtins, which we're not on GNU/Linux unless you're using -ffast-math. If you're using -ffast-math, the fsincos optimization is appropriate anyway because you want fast. If you're not using -ffast-math it's still appropriate, because we're using an accurate libm. Andrew.
