On Fri, 14 Jun 2024, Richard Sandiford wrote:
> Richard Biener <rguent...@suse.de> writes:
> > The following retires vcond{,u,eq} optabs by stopping to use them
> > from the middle-end. Targets instead (should) implement vcond_mask
> > and vec_cmp{,u,eq} optabs. The PR this change refers to lists
> > possibly affected targets - those implementing these patterns,
> > and in particular it lists mips, sparc and ia64 as targets that
> > most definitely will regress while others might simply remove
> > their vcond{,u,eq} patterns.
> >
> > I'd appreciate testing, I do not expect fallout for x86 or arm/aarch64.
> > I know riscv doesn't implement any of the legacy optabs. But less
> > maintained vector targets might need adjustments.
> >
> > I want to get rid of those optabs for GCC 15. If I don't hear from
> > you I will assume your target is fine.
>
> Great! Thanks for doing this.
>
> Is there a plan for how we should handle vector comparisons that
> have to be done as the inverse of the negated condition? Should
> targets simply not provide vec_cmp for such conditions and leave
> the target-independent code to deal with the fallout? (For a
> standalone comparison, it would invert the result. For a VEC_COND_EXPR
> it would swap the true and false values.)
I would expect that the ISEL pass which currently deals with finding
valid combos of .VCMP{,U,EQ} and .VCOND_MASK deals with this.
So how do we deal with this right now? I expect RTL expansion will
do the inverse trick, no?
Thanks,
Richard.
> Richard
>
> >
> > Thanks,
> > Richard.
> >
> > PR middle-end/114189
> > * optabs-query.h (get_vcond_icode): Always return CODE_FOR_nothing.
> > (get_vcond_eq_icode): Likewise.
> > ---
> > gcc/optabs-query.h | 13 ++++---------
> > 1 file changed, 4 insertions(+), 9 deletions(-)
> >
> > diff --git a/gcc/optabs-query.h b/gcc/optabs-query.h
> > index 0cb2c21ba85..31fbce80175 100644
> > --- a/gcc/optabs-query.h
> > +++ b/gcc/optabs-query.h
> > @@ -112,14 +112,9 @@ get_vec_cmp_eq_icode (machine_mode vmode, machine_mode
> > mask_mode)
> > mode CMODE, unsigned if UNS is true, resulting in a value of mode
> > VMODE. */
> >
> > inline enum insn_code
> > -get_vcond_icode (machine_mode vmode, machine_mode cmode, bool uns)
> > +get_vcond_icode (machine_mode, machine_mode, bool)
> > {
> > - enum insn_code icode = CODE_FOR_nothing;
> > - if (uns)
> > - icode = convert_optab_handler (vcondu_optab, vmode, cmode);
> > - else
> > - icode = convert_optab_handler (vcond_optab, vmode, cmode);
> > - return icode;
> > + return CODE_FOR_nothing;
> > }
> >
> > /* Return insn code for a conditional operator with a mask mode
> > @@ -135,9 +130,9 @@ get_vcond_mask_icode (machine_mode vmode, machine_mode
> > mmode)
> > mode CMODE (only EQ/NE), resulting in a value of mode VMODE. */
> >
> > inline enum insn_code
> > -get_vcond_eq_icode (machine_mode vmode, machine_mode cmode)
> > +get_vcond_eq_icode (machine_mode, machine_mode)
> > {
> > - return convert_optab_handler (vcondeq_optab, vmode, cmode);
> > + return CODE_FOR_nothing;
> > }
> >
> > /* Enumerates the possible extraction_insn operations. */
>
--
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)
