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Re: PRE (sometimes) confuses ivopts/scev?
- From: Richard Guenther <rguenth at tat dot physik dot uni-tuebingen dot de>
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Ulrich Weigand <uweigand at de dot ibm dot com>, <gcc at gcc dot gnu dot org>
- Date: Tue, 25 Jan 2005 15:46:55 +0100 (CET)
- Subject: Re: PRE (sometimes) confuses ivopts/scev?
On Tue, 25 Jan 2005, Daniel Berlin wrote:
> >>> if (firstinsideloop ^ secondinsideloop)
> >>
> >> This is pretty much what i'm testing now.
> >
> > This helps - though for the particular function there is now
> >
> > Insertions:0
> > New PHIs:0
> > Eliminated:0
> > Constified:0
> >
> > but I didn't expect any obvious redundant computations in the
> > function anyway.
>
> However, this patch causes us to miss the invariant code in ssa-pre-3.c,
> so we need *some* test there that avoids wraparounds while still catching
> invariant code.
I created PR tree-optimization/19624 with my testcase (took a day to
reduce...).
Richard.
--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/