Re: [PATCH 2/3] testsuite: Require 128-bit vectors for bb-slp-pr95839.c

[Richard Biener <richard.guenther@gmail.com>]

On Wed, Jul 19, 2023 at 4:34 PM Maciej W. Rozycki <macro@embecosm.com> wrote:
>
> On Wed, 12 Jul 2023, Richard Biener wrote:
>
> > > > That said, we should handle this better so can you file an
> > > > enhancement bugreport for this?
> > >
> > >  Filed as PR -optimization/110630.
> >
> > Thanks!
>
>  Thanks for making this improvement.  I've checked MIPS results and code
> produced now is as follows:
>
>         daddiu  $sp,$sp,-64
>         sd      $5,24($sp)
>         sd      $7,40($sp)
>         ldc1    $f0,24($sp)
>         ldc1    $f1,40($sp)
>         sd      $4,16($sp)
>         sd      $6,32($sp)
>         ldc1    $f2,32($sp)
>         add.ps  $f1,$f0,$f1
>         ldc1    $f0,16($sp)
>         add.ps  $f0,$f0,$f2
>         sdc1    $f1,56($sp)
>         ld      $3,56($sp)
>         sdc1    $f0,48($sp)
>         ld      $2,48($sp)
>         jr      $31
>         daddiu  $sp,$sp,64
>
> which does do vector stuff now, although it's still considerably worse
> than my handwritten example:
>
> > >         dmtc1   $4,$f0
> > >         dmtc1   $5,$f1
> > >         dmtc1   $6,$f2
> > >         dmtc1   $7,$f3
> > >         add.ps  $f0,$f0,$f1
> > >         add.ps  $f2,$f2,$f3
> > >         dmfc1   $2,$f0
> > >         jr      $31
> > >         dmfc1   $3,$f2
>
> Or I'd say it's pretty terrible, but given the current situation with the
> MIPS backend I'm going to leave it to the new maintainer to sort out.

Yeah, I also wondered what is wrong ... I suspect it's the usual issue
of parameter passing causing spilling ...

> > >  Do you agree it still makes sense to include bb-slp-pr95839-v8.c with the
> > > testsuite?
> >
> > Sure, more coverage is always  nice.
>
>  Thanks, committed (with the `vect64' requirement removed, as we can take
> it for granted with `vect_float').
>
>   Maciej