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Re: [tree-ssa] New regressions as of 2003-11-04
- From: Andrew MacLeod <amacleod at redhat dot com>
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: Jeff Law <law at redhat dot com>, Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>, Daniel Berlin <dberlin at dberlin dot org>, JanHubicka <jh at suse dot cz>, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: 04 Nov 2003 21:50:41 -0500
- Subject: Re: [tree-ssa] New regressions as of 2003-11-04
- References: <200311042151.hA4LpHjB017544@speedy.slc.redhat.com> <1067997120.3170.3.camel@frodo.toronto.redhat.com>
On Tue, 2003-11-04 at 20:52, 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?
What does going out of SSA in DOM order do? SSA->normal doesnt klnow
anything about equivilences, and Im not too keen on teaching it anything
about them.
I dont understand why the existing routines wont work with a little
tweaking... The inforamtion is still identical, there just happens to be
a branch in between instead of the stmt hung off the COND_EXPR. If the
existing stuff does destroy the CFG, perhaps we ought to do this part of
it before we destroy the CFG.....
Andrew