On May 27, 2018 1:25:25 AM GMT+02:00, Allan Sandfeld Jensen <li...@carewolf.com> wrote: >On Sonntag, 27. Mai 2018 00:05:32 CEST Segher Boessenkool wrote: >> On Sat, May 26, 2018 at 11:32:29AM +0200, Allan Sandfeld Jensen >wrote: >> > I brought this subject up earlier, and was told to suggest it again >for >> > gcc 9, so I have attached the preliminary changes. >> > >> > My studies have show that with generic x86-64 optimization it >reduces >> > binary size with around 0.5%, and when optimizing for x64 targets >with >> > SSE4 or better, it reduces binary size by 2-3% on average. The >> > performance changes are negligible however*, and I haven't been >able to >> > detect changes in compile time big enough to penetrate general >noise on >> > my platform, but perhaps someone has a better setup for that? >> > >> > * I believe that is because it currently works best on >non-optimized code, >> > it is better at big basic blocks doing all kinds of things than >tightly >> > written inner loops. >> > >> > Anythhing else I should test or report? >> >> What does it do on other architectures? >> >> >I believe NEON would do the same as SSE4, but I can do a check. For >architectures without SIMD it essentially does nothing.
By default it combines integer ops where possible into word_mode registers. So yes, almost nothing. Richard. >'Allan
