On Wed, Sep 16, 2020 at 7:46 AM Richard Sandiford
<richard.sandif...@arm.com> wrote:
>
> "H.J. Lu" <hjl.to...@gmail.com> writes:
> > On Tue, Sep 15, 2020 at 7:44 AM Richard Sandiford
> > <richard.sandif...@arm.com> wrote:
> >>
> >> Thanks for looking at this.
> >>
> >> "H.J. Lu" <hjl.to...@gmail.com> writes:
> >> > commit 1bcb4c4faa4bd6b1c917c75b100d618faf9e628c
> >> > Author: Richard Sandiford <richard.sandif...@arm.com>
> >> > Date: Wed Oct 2 07:37:10 2019 +0000
> >> >
> >> > [LRA] Don't make eliminable registers live (PR91957)
> >> >
> >> > didn't make eliminable registers live which breaks
> >> >
> >> > register void *cur_pro asm("reg");
> >> >
> >> > where "reg" is an eliminable register. Make fixed eliminable registers
> >> > live to fix it.
> >>
> >> I don't think fixedness itself is the issue here: it's usual for at
> >> least some registers involved in eliminations to be fixed registers.
> >>
> >> I think what makes this case different is instead that cur_pro/ebp
> >> is a global register. But IMO things have already gone wrong if we
> >> think that a global register is eliminable.
> >>
> >> So I wonder if instead we should check global_regs at the beginning of:
> >>
> >> for (i = 0; i < fp_reg_count; i++)
> >> if (!TEST_HARD_REG_BIT (crtl->asm_clobbers,
> >> HARD_FRAME_POINTER_REGNUM + i))
> >> {
> >> SET_HARD_REG_BIT (eliminable_regset,
> >> HARD_FRAME_POINTER_REGNUM + i);
> >> if (frame_pointer_needed)
> >> SET_HARD_REG_BIT (ira_no_alloc_regs,
> >> HARD_FRAME_POINTER_REGNUM + i);
> >> }
> >> else if (frame_pointer_needed)
> >> error ("%s cannot be used in %<asm%> here",
> >> reg_names[HARD_FRAME_POINTER_REGNUM + i]);
> >> else
> >> df_set_regs_ever_live (HARD_FRAME_POINTER_REGNUM + i, true);
> >>
> >> (ira_setup_eliminable_regset), and handle the global_regs[] case in
> >> the same way as the else case, i.e. short-circuiting both of the ifs.
> >>
> >
> > Like this?
>
> Sorry for the delay. I was testing this in parallel.
>
> Bootstrapped & regression-tested on x86_64-linux-gnu.
>
Thanks.
--
H.J.
