On Mon, 26 Jun 2017, Richard Sandiford wrote: > > Non-generic builtins like copysign are such a pain... We also end up > > missing the 128-bit case that way (pre-existing problem, not your patch). > > We seem to have a corresponding internal function, but apparently it is > > not used until expansion (well, maybe during vectorization). > > It should be OK to introduce uses of the internal functions whenever > it's useful. The match code will check that the internal function is > implemented before allowing the transformation.
How well would internal functions work with some having built-in functions only for float, double and long double, others (like copysign) having them for all the _FloatN and _FloatNx types? (Preferably of course the built-in functions for libm functions would generally exist for all the types. I didn't include that in my patches adding _FloatN/_FloatNx support <https://gcc.gnu.org/ml/gcc-patches/2016-08/msg01290.html> <https://gcc.gnu.org/ml/gcc-patches/2016-08/msg01442.html> and noted various issues to watch out for there, especially increasing the size of the enum of built-in functions and the startup cost of initializing them. There are other optimizations with similar issues of only covering float, double and long double.) -- Joseph S. Myers jos...@codesourcery.com
