Re: [UPC 14/22] constant folding changes

[Gary Funck <gary at intrepid dot com>]

On 12/01/15 12:46:01, Richard Biener wrote:
> On Mon, 30 Nov 2015, Gary Funck wrote:
> > UPC pointers-to-shared (aka shared pointers) are not interchangeable
> > with integers as they are in regular "C".  Therefore, additions
> > and subtraction operations which involve UPC shared pointers
> > should not be further simplified.
> 
> This looks worrysome.  I suppose this applies to simplifications
> done before lowering only?  If so I wonder if not using regular
> plus/minus/convert/nop for operations on UPC shared pointers is
> better than introducing this kind of checks.

I suppose that is a possibility.  We could introduce
UPC_POINTER_PLUS, UPC_POINTER_CONVERT, and so-on as needed.
Just not sure how many places that for example,
UPC_POINTER_PLUS will keep showing up alongside POINTER_PLUS
and similarly UPC_POINTER_CONVERT and CONVERT.

After lowering, All UPC-specific operations have been replaced
with the GENERIC code that implements them.  We still retain
the UPC pointer-to-shared types in the tree, rather than
lowering everything to the internal representation of the
pointer-to-shared type.  I recall trying to replace
pointers-to-shared with their internal representation and
ran into some issues.  I think one of them is that procedures
accepting pointers-to-shared as parameters would have
an apparent type mis-match. It might have impacted debug info.
generation as well.  Just don't recall.

- Gary