On September 29, 2015 9:27:13 PM GMT+02:00, fxcoud...@gmail.com wrote: >It cannot be done in the front-end, but has to happen during value >propagation in the middle-end. But the middle-end only handles known >*_EXPR and built-ins. So this would require adding either a POWINT_EXPR >or a type-generic __builtin_powint. No small task. > >I think there is already a PR for that (at the very least, I have >looked into it and discussed it with some middle-end experts before). I >cannot look it up right now, it's the interlude of Don Govanni at Paris >Opera :)
The middle-end knows sth remotely related, __builtin_powi, already. What we'd need though is a way for a frontend to specify which library function to use as fallback. In principle I would suggest to add a general POW_EXPR tree code. But the issue as what library call to expand to remains. Usually such functions reside in libgcc (powi has some there). Richard. >FX
