RTL alias analysis

[Richard Guenther]

On 1/20/06, Steven Bosscher <steven@gcc.gnu.org> wrote:
> On Tuesday 03 January 2006 17:27, Richard Henderson wrote:
> > On Mon, Jan 02, 2006 at 12:45:49AM -0500, Daniel Berlin wrote:
> > > ... the real
> > > solution is to transfer the information that the stack space sharing
> > > knows into some simple set form, and use *that directly* in alias.c, and
> > > check it *first*, so that if they have the same stack slot, we say there
> > > is a dependence, even if the memory expressions/types/etc look
> > > different.
> >
> > ... And that doesn't work for the test case, because we've
> > carefuly thrown away any information that might have given
> > us any information wrt the stack slots.
> >
> > I'll have to give this some thought.
>
> Hi rth,
>
> Is your "think this over"-process still runnig? ;-)
>
> We've tried to add some more food for thought in the audit trail
> of PR25654, which is tracking this issue.  Hope you'll add your
> thoughts so far, so that we can make some progress on getting a
> PR GCC 4.1 regression fixed...

A patch was also posted based on ideas in the audit trail.  It's third
incarnation at
http://gcc.gnu.org/ml/gcc-patches/2006-01/msg00967.html
would need a review.

Richard.