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
