On Tue, Feb 26, 2019 at 04:58:17PM -0700, Jeff Law wrote: > On 2/26/19 4:19 PM, Segher Boessenkool wrote: > > On Tue, Feb 26, 2019 at 10:07:54AM -0700, Jeff Law wrote: > For gcc-10 we should: > > 1. Avoid really stupid stuff in init-regs. > > 2. Avoid really stupid stuff in the splitters. > > 3. Make REE SUBREG-aware > > 4. Seriously consider a RTL DCE pass after post-reload splitting > > But none of those would actually fix this BZ :-)
Since we are talking about pie-in-the-sky stuff... I'd like to run some kind of mini-combine after every split pass (just on the new insns). As it is the (later) splitters often leave non-optimal code unless a lot of work is put into those splitters. We should not have as many late splitters as we do, but for those we do need, it would be helpful if the compiler could do simple combinations without having to hand-code them. > > [ I don't see any problems with -O2 btw, only with -O1, so should we care > > at all anyway? ] > You can get this stuff at -O2 on other platforms. It's far more common > than I ever imagined. Yeah, that's because the testcase uses -fno-split-wide-types. The subreg passes do great work :-) Segher
