[gfortran] Fix NULL reference types.

[Richard Henderson]

On Thu, Aug 19, 2004 at 01:54:53PM -0400, Richard Kenner wrote:
>     I suppose that we could provide the same information I wanted to convey 
>     with REFERENCE_TYPE to the optimizer in some other way: a bit on 
>     VAR_DECLs, PARM_DECLs, FIELD_DECLs, etc. that says "never NULL".
> 
> And INDIRECT_REF, which is somewhat of the harder one.  That's why I
> think types are the best approach.

Hmm?  Are you thinking reference-to-reference?

> The other issue is when we know that an indirect reference can't trap, such
> as the CHAIN reference.

TREE_THIS_NOTRAP already exists.


r~