On Fri, Nov 22, 2024 at 9:16 PM Richard Biener <rguent...@suse.de> wrote:
>
> On Fri, 22 Nov 2024, liuhongt wrote:
>
> > It could cause weired spill in RA when register pressure is high.
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> > Ok for trunk?
> >
> > BTW, It's difficult to get a decent testcase for the issue since the spill
> > is not exposed in simple testcase.
>
> I think it's a good patch independent on the spill issue given it
> avoids false dependences on the scratch reg contents.
Yes, committed, and will backport to release branches.
> Richard.
>
> > gcc/ChangeLog:
> >
> > PR target/117562
> > * config/i386/sse.md (vec_unpacks_hi_v4sf): Initialize
> > operands[2] with CONST0_RTX.
> > ---
> > gcc/config/i386/sse.md | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
> > index 72acd5bde5e..498a42d6e1e 100644
> > --- a/gcc/config/i386/sse.md
> > +++ b/gcc/config/i386/sse.md
> > @@ -10424,7 +10424,10 @@ (define_expand "vec_unpacks_hi_v4sf"
> > (match_dup 2)
> > (parallel [(const_int 0) (const_int 1)]))))]
> > "TARGET_SSE2"
> > - "operands[2] = gen_reg_rtx (V4SFmode);")
> > +{
> > + operands[2] = gen_reg_rtx (V4SFmode);
> > + emit_move_insn (operands[2], CONST0_RTX (V4SFmode));
> > +})
> >
> > (define_expand "vec_unpacks_hi_v8sf"
> > [(set (match_dup 2)
> >
>
> --
> Richard Biener <rguent...@suse.de>
> SUSE Software Solutions Germany GmbH,
> Frankenstrasse 146, 90461 Nuernberg, Germany;
> GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
--
BR,
Hongtao
