On Tue, Apr 30, 2019 at 07:57:20AM -0600, Jeff Law wrote: > > Just curious, do we want to add math identities like above to match.pd ? > I'd think so. > > > > In practice, I am not sure how often we'd see "tanh * cosh" instead > > of sinh directly in source, > We're often surprised when what ultimately shows up in sources :-) And > a transformation that allows us to turn two transcendentals and a > multiplication into a single transcendental is going to be a big win.
I guess an important question is if such transformations need to be guarded by some -ffast-math suboptions, whether those transformations work properly for signed zeros, NaNs, sNaNs, infinities, guarantee the same ulp, have the same -ferrno-math behavior etc. Jakub