On Thu, May 25, 2023 at 10:29:47AM -0400, Vladimir Makarov wrote: > > On 5/17/23 02:57, liuhongt wrote: > >r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost > >calculation when the preferred register class are not known yet. > >It regressed powerpc PR109610 and PR109858, it looks too aggressive to use > >NO_REGS when mode can be allocated with GENERAL_REGS. > >The patch takes a step back, still use GENERAL_REGS when > >hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS. > >Kewen confirmed the patch fixed PR109858, I vefiried it also fixed > >PR109610. > > > >Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}. > >No big performance impact for SPEC2017 on icelake server. > >Ok for trunk? > > > >gcc/ChangeLog: > > > > * ira-costs.cc (scan_one_insn): Only use NO_REGS in cost > > calculation when !hard_regno_mode_ok for GENERAL_REGS and > > mode, otherwise still use GENERAL_REGS. > > Thank you for the patch. It looks good for me. It is ok to commit it > into the trunk.
Thanks everyone involved for fixing this nasty regression! Much appreciated. Segher