RFA: Fix ICE related to ADDR_EXPR forward propagation

[Jeffrey A Law]

On Fri, 2005-05-20 at 07:12 -0400, Daniel Berlin wrote:
> On Fri, 2005-05-20 at 07:23 +0100, Richard Sandiford wrote:
> > Mainline currently segfaults while trying to build newlib's hash.c.
> > The problem seems to be caused by the recent patch to forward-propagate
> > ADDR_EXPRs.  The idea of those changes is to replace:
> > 
> >     t1 = &thing[0]
> >     t2 = index * scale
> >     t3 = (ptr_type) t2
> >     result = t1 + t3
> > 
> > with:
> > 
> >     result = &thing[index]
> 
> 
> >   I'm not exactly 100%
> > confident this will be accepted as the right fix though. ;)
> 
> 
> You want to call recompute_tree_invariant_for_addr_expr on the ADDR_EXPR
> after the operands are replaced.
> 
> It'll do what it says (recompute the invariant flag, etc, as
> approriate).
Andrew Pinski has a patch for that -- I've twiddled it slightly
(moved it into the cleanup routine recently added by RTH).

I just need to verify that it still fixes the bugs it's supposed
to fix and it'll be ready to be checked in.

jeff