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Re: Middle-end and optimization regressions: what should we do?
- From: Janis Johnson <janis187 at us dot ibm dot com>
- To: Steve Kargl <sgk at troutmask dot apl dot washington dot edu>
- Cc: Fran?ois-Xavier Coudert <fxcoudert at gmail dot com>, "fortran at gcc dot gnu dot org" <fortran at gcc dot gnu dot org>, gcc at gcc dot gnu dot org
- Date: Thu, 28 Jul 2005 15:38:24 -0700
- Subject: Re: Middle-end and optimization regressions: what should we do?
- References: <19c433eb0507281026355950aa@mail.gmail.com> <20050728174148.GA64356@troutmask.apl.washington.edu>
On Thu, Jul 28, 2005 at 10:41:48AM -0700, Steve Kargl wrote:
> On Thu, Jul 28, 2005 at 07:26:22PM +0200, Fran?ois-Xavier Coudert wrote:
> >
> > PR 22619 and PR 22509 are two examples of recent 4.1 regressions that
> > showed up in gfortran, due to middle-end or optimization bugs (only
> > happen at -O3). Since these are regressions, they should be treated
> > before a long time passes, but since both source codes are Fortran, I
> > guess people don't (and won't) want to look at them.
> >
> > How can we help here? Is there a way to make gfortran output a
> > complete GIMPLE tree, that could be used for middle-end hackers to
> > determine where the problem is? Or are we doomed to a dichotomy to
> > know which patch caused these regressions?
>
> These types of regressions have essentially halted my testing
> and development on gfortran because I usually try to identify
> the exact ChangeLog entry associated with the problem. This
> typically involves a binary search for the problem with a
> bootstrap in a clean directory for each "cvs update -D <date>".
In case you're not already aware of them, see contrib/reghunt and
http://gcc.gnu.org/bugs/reghunt.html.
Janis