https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116896
--- Comment #22 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Uroš Bizjak from comment #21) > (In reply to Jakub Jelinek from comment #19) > > Created attachment 59273 [details] > > gcc15-pr116896-inc2.patch > > > > I've tried to improve the signed int <=> case (the only one which doesn't > > use sbb and so needs two xors first), but unfortunately that doesn't seem to > > work at all, the IL is how I'd like to see it at the end, but then combine > > happily turns those *setcc_qi_slp back into *setcc_si_1_movzbl and removes > > the clear instructions. > > So, I think all we can do is some extra peephole2 to deal with it (though in > > the jp case it will have to use to movl $0, %reg). Huh, another idea is to add a variant of *setcc_qi_slp, perhaps implemented with unspec or (better?) add some unspec tag to it. If we already emit optimal code at the expand time, then there is not a lot of work left for optimization passes anyway.
