On Thu, 2020-08-13 at 13:29 -0500, Segher Boessenkool wrote: > On Thu, Aug 13, 2020 at 11:09:10AM -0700, Carl Love wrote: > > The builtins > > > > vector signed int vec_signexti (vector signed char a) > > vector signed long long vec_signextll (vector signed char a) > > vector signed int vec_signexti (vector signed short a) > > vector signed long long vec_signextll (vector signed short a) > > vector signed long long vec_signextll (vector signed int a) > > > > were defined in the function prototypes directory in box called > > "RFC > > 2608 - 128-bit Binary Integer Operations". The document the new > > P10 > > builtins. However, this subset of the newly defined builtins for > > P10 > > can be implemented with existing Power 9 instructions. That was > > the > > point of the comment. > > Ah, I see :-) > > > That is probably a level of detail that is not > > really needed in the GCC code comment. Probably best to just > > change > > the comment to read something like "ISA 3.0 sign extend builtins". > > Sounds good.
As long as there are no issues defining the builtins for 3.0 here. AFAIK they are not documented in ISA 3.0. This is a happy accident that these ISA 3.1 builtins can be implemented with existing support. > > > My thought for calling it out is that they could be back ported to > > an > > earlier GCC version since they use Power 9 instructions but it is > > probably not worth the effort unless there is an explicit request > > for > > them. > > Yeah. Thanks for the explanation! > > > Segher
