On Wed, Feb 5, 2020 at 12:03 PM Jakub Jelinek <ja...@redhat.com> wrote: > > On Wed, Feb 05, 2020 at 11:46:51AM +0100, Uros Bizjak wrote: > > I think we should just enable split4 also for -O0. This would also > > allow us to remove the "optimize > 0" check above and allow us to > > generate a bit more optimal code even with -O0 for > > TARGET_SSE_PARTIAL_REG_DEPENDENCY and TARGET_AVOID_FALSE_DEP_FOR_BMI. > > The -O0 passes are: > test.c.284r.ira > test.c.285r.reload > # placement of split2 > test.c.292r.pro_and_epilogue > test.c.295r.jump2 > # placement of split4 > # placement of split3 > test.c.307r.stack > test.c.308r.alignments > test.c.310r.mach > test.c.311r.barriers > # placement of split5 > test.c.316r.shorten > test.c.317r.nothrow > test.c.318r.dwarf2 > test.c.319r.final > > It really doesn't matter if for -O0 STACK_REGS we enable split4 or > split3, it is the same location, just split3 is better named (split before > reg-stack, which is run even at -O0, rather than split before sched2, which > is not run at -O0). > > I think the primary question is, do we for -O0 need to enable split2 (as in, > will anything in pro_and_epilogue or jump2 passes benefit from the > splitting and worth running two -O0 post-RA split passes), then we could go > with the first patch I've posted, or nothing benefits from it in the two > passes and it is ok to split only before stack, in that case we can go with > the third patch.
Oh, I see. No passes get scheduled between split3 and split4. Looks to me that your third patch is then the way to go. Uros.
