On Thu, May 28, 2026 at 11:58 AM Uros Bizjak <[email protected]> wrote:
>
> On Thu, May 28, 2026 at 11:48 AM Jakub Jelinek <[email protected]> wrote:
> >
> > On Thu, May 28, 2026 at 11:31:27AM +0200, Uros Bizjak wrote:
> > > Hm, OTOH, is this condition correct:
> > >
> > >     case TYPE_LEA:
> > >       if (TARGET_APX_NDD && <nf_applied>)
> > >     return "%{nf%} add{<imodesuffix>}\t{%2, %1, %0|%0, %1, %2}";
> > >       else
> > >     return "#";
> > >
> > > Should it be "TARGET_APX_NDD || <nf_applied>"?
> >
> > The pattern is weird, but TARGET_APX_NDD || <nf_applied> would be wrong.
> > Without TARGET_APX_NDD there is no 3 operand add, so we can't use that.
> > Of course, question is if there will be CPUs with just APX-NF and not
> > APX-NDD or with just APX-NDD and not APX-NF.
> >
> > I'd say it is a bad idea to have the "lea" variant come before the
> > 3 apx_ndd variants, if the lea variant came last, then at least the r <- r, 
> > l
> > case would be covered for TARGET_APX_NDD by the earlier (but now later)
> > r <- rje, r variant and could then emit either the 3 operand add or 3
> > operand add with {nf}.  Anyway, with the current position it could also be
> >   if (TARGET_APX_NDD)
> >     return "<nf_prefix>add{<imodesuffix>}\t{%2, %1, %0|%0, %1, %2}";
> >   else
> >     {
> >       operands[3] = gen_rtx_PLUS (<MODE>mode, operands[1], operands[2]);
> >       return "lea{<imodesuffix>}\t{%E3, %0|%0, %E3}";
> >     }
>
> I think that the correct solution is to put LEA at the end. LEA
> alternative is intended for non-NDD cases to allow two-register
> operation, but NDD should override it, w/ or w/o NF. Let's ask
> Hongtao.

Eh, a thinko. *Without* NDD, we still need LEA. Let's go forward with
your patch, it is the safest solution.

Uros.

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