[Patch 1/5] rs6000, Add 128-bit sign extension support
Thu Aug 13 18:29:01 GMT 2020
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".
> 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
Yeah. Thanks for the explanation!
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