Re: Re: [PATCH] Canonical types (1/3)

["Doug Gregor" <doug dot gregor at gmail dot com>]

On 12/4/06, Richard Kenner <kenner@vlsi1.ultra.nyu.edu> wrote:
> > +  if (TYPE_CANONICAL (to_type) != to_type)
> > +    TYPE_CANONICAL (t) =
> > +      build_pointer_type_for_mode (TYPE_CANONICAL (to_type),
> > +                                mode, can_alias_all);
>
> Minor issue: the "=" is on the wrong line.

Ah, thanks.

> > > +      type = build_variant_type_copy (orig_type);
> > >        TYPE_ALIGN (type) = boundary;
> > > +      TYPE_CANONICAL (type) = TYPE_CANONICAL (orig_type);
> >
> > Eek.  So, despite having different alignments, we consider these types
> > "the same"?  If that's what we already do, then it's OK to preserve that
> > behavior, but it sure seems worrisome.
>
> I'm concerned about that as well.  I think we need a more precise definition
> someplace of what is allowed to differ between two "variants" of a type.

I've been following whatever "comptypes" does, because that's the
behavior canonical types need to mimic to provide the same behavior
that we have now.

 Cheers,
 Doug