Re: [tree-ssa] New regressions as of 2003-11-04

[Daniel Berlin <dberlin at dberlin dot org>]

On Nov 4, 2003, at 8:52 PM, Diego Novillo wrote:

> On Tue, 2003-11-04 at 16:51, law@redhat.com wrote:
>
> > if (set != -1)
> >   goto lab1;
> > else
> >   goto lab2;
> >
> > lab1:
> >   set = 0;
> >   goto lab3;
> > lab2:
> >   set = -1;
> > lab3:
> >   [ ... ]
> >
> > Which looks precisely like what we've got now.
> Yes, but what I had in mind is to go out of SSA in DOM order.  Andrew
> was thinking of doing some post-processing in the out-of-ssa pass.
> Maybe we could add this as well.
>
> Andrew, does that sound too gross for the out-of-ssa pass?

Please be aware, that if you guys want, I can also temporarily fix the 
regression at the cost of possibly redoing dominators + dominance 
frontiers for every lexical expression we PRE (This is absolute worst 
case, where every expression has a different set of critical edges we 
might need to insert on.  I don't know how often this happens in 
practice).

Of course, this is just a workaround, and a possibly expensive one at 
that, but it would make the regression go away for now.

Just offering it as an option if none of us have time to try to fix it 
the right way, since it is a regression my patch exposed.

--Dan