xunxun<xunxun1982@gmail.com> writes:
If you switch to using SSE floating-point, e.g. using "-mfpmath=sse",
it will still call the library functions even when using -ffast-math
(because the SSE unit doesn't have special instructions like "fsin" or
"f2xm1"). I think SSE FP is typically faster than the 387 for many
CPUs anyway.
Well, that's right.
But in my experience, -mfpmath=sse will slow my code very much.
Hmm, I've always found SSE FP to be a speedup -- sometimes a _big_
speedup -- over 387 FP, at least when one is using mostly primitive FP
operations (mul, divide, sqrt, etc) ... I think it's worth testing, at
least.