Re: ptx preliminary address space fixes [1/4]

[Bernd Schmidt <bernds at codesourcery dot com>]

On 09/12/2014 01:48 PM, Richard Biener wrote:
> On Fri, Sep 12, 2014 at 1:15 PM, Bernd Schmidt <bernds@codesourcery.com> wrote:
> > On 09/11/2014 01:29 PM, Richard Biener wrote:
> > > +  if (TREE_CODE (type) == ARRAY_TYPE)
> > > +    TREE_TYPE (type) = apply_as_to_type (TREE_TYPE (type), as);
> > >
> > > why is this necessary for ARRAY_TYPE but not for sth like
> > > a RECORD_TYPE or a POINTER_TYPE?
> >
> >
> > Still testing whether I actually strictly need it for ARRAY_TYPE nowadays
> > (these patches are really old...). However, the TYPE_FIELDS of a RECORD_TYPE
> > seem to be mostly ignored once the frontends are done, but it's very easy
> > for other parts of the compiler to take the TREE_TYPE of an ARRAY_TYPE.
> > Fixing that up is simple and seems like a good thing to do for consistency
> > (I notice that maybe I should add VECTOR_TYPE).
>
> Well, for an access a->b the COMPONENT_REF specifies the type
> of the reference which uses the type of the FIELD_DECL...  IVOPTs
> for example may produce
>
>   ptr *p = &a->b;
>   *p;
>
> from that with ptr * built from TREE_TYPE of that expression.
>
> Btw, a similar type as VECTOR_TYPE is COMPLEX_TYPE.

Ok, so testing seems to show that nothing breaks with the ARRAY_TYPE 
special case removed. However, I remembered another reason to do this, 
and it's for consistency with how address spaces are represented in 
other parts of the compiler - specifically, the C frontend.

C has the notion that arrays don't have type qualifiers, so to get the 
address space of an array you'd have to look at the address space of its 
element types. Joseph has in the past rejected patches to fix this 
inconsistency. For other types like structs or vectors (as we saw in the 
tree-vect patch) it's the outermost type that has the address space 
information.

I guess I'll declare myself agnostic, let me know whatever variant you 
want to have here (fixing up all types or not fixing arrays) and I'll 
make a new patch.


Bernd