Re: [RFA] More type narrowing in match.pd V2

[Marc Glisse <marc dot glisse at inria dot fr>]

On Mon, 18 May 2015, Richard Biener wrote:

> On Thu, May 14, 2015 at 4:28 PM, Jeff Law <law@redhat.com> wrote:
> > On 05/14/2015 08:04 AM, Marc Glisse wrote:
> > > On Fri, 1 May 2015, Jeff Law wrote:
> > >
> > > > Slight refactoring of the condition by using types_match as suggested
> > > > by Richi.  I also applied the new types_match to 2 other patterns in
> > > > match.pd where it seemed clearly appropriate.
> > >
> > >
> > > I would like to propose this small tweak (regtested ok). If we had a
> > > different type for trees and types, this would be overloading the
> > > function. We already do this in a few places, and I find the resulting
> > > shorter code more readable.
> > >
> > > 2015-05-14  Marc Glisse  <marc.glisse@inria.fr>
> > >
> > >      * generic-match-head.c (types_match): Handle non-types.
> > >      * gimple-match-head.c (types_match): Likewise.
> > >      * match.pd: Remove unnecessary TREE_TYPE for types_match.
> >
> > Update the comment for types_match and this is fine.
>
> No - it breaks genmatch autodetection of what trees escape.  It special-cases
> TREE_TYPE ().  See capture_info::walk_c_expr:

Oh, I didn't know that.

>  /* Give up for C exprs mentioning captures not inside TREE_TYPE ().  */
>  unsigned p_depth = 0;
>
> so the patch will pessimize GENERIC folding.
>
> Please do not apply.

I think it was already applied. Feel free to revert it, or tell me and 
I'll do it next week-end (from your next message I don't really know if it 
should be reverted or not).

--
Marc Glisse