Jeff Law wrote: > Right. exp is painful in glibc, but pow is *dramatically* more painful > and likely always will be. > > Siddhesh did some great work in bringing those costs down in glibc but > the more code we can reasonably shunt into exp instead of pow, the better. > > It's likely pow will always be significantly more expensive than exp. > It's also likely that predicting when these functions are going to go > off the fast paths is painful.
With a modern implementation there won't be any slow path - it's completely unnecessary, and you can get 100x speedup by simply doing things in a sane way. Szabolc's version of powf is almost literally doing exp(log(x) * y), so exp is about twice as fast as pow. Wilco
