On Wed, 29 Apr 2020, Jakub Jelinek wrote:
> On Tue, Apr 28, 2020 at 11:16:13AM +0200, Richard Biener wrote:
> > I think we generally want to use :s, but OTOH even for your new case,
> > since you restrict to nop-conversions, :s isn't strictly needed since
> > VN should know how to materialize nop-converted variants. I think
> > it's different for the 2nd case you add since there we deal with
> > bitops in different sign.
> >
> > So maybe just remove the single_use () calls?
>
> I've tried doing that, but that regresses e.g.
> void bar (unsigned int, unsigned int);
>
> unsigned int
> foo (int x, int y)
> {
> unsigned int x2 = x;
> unsigned int y2 = y;
> bar (x2, y2);
> return x2 | y2;
> }
>
> @@ -6,12 +6,14 @@ foo (int x, int y)
> unsigned int y2;
> unsigned int x2;
> unsigned int _7;
> + int _8;
>
> <bb 2> [local count: 1073741824]:
> x2_2 = (unsigned int) x_1(D);
> y2_4 = (unsigned int) y_3(D);
> bar (x2_2, y2_4);
> - _7 = x2_2 | y2_4;
> + _8 = x_1(D) | y_3(D);
> + _7 = (unsigned int) _8;
> return _7;
>
> }
>
> As the patch was meant purely as an IL size optimization, that is not the
> case here.
Hmm OK. Let's go with your original patch then for GCC 11.
Richard.
> > > Or should I e.g. move this GIMPLE rule as a separate simplify (under the
> > > same for) and then use :s in there?
> >
> > That wouldn't work, if a structural pattern matched others are not
> > considered so it wouldn't ever be used. genmatch even warns for this
> > I think.
>
> Ah, ok.
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
