[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

["richard at nildram dot co dot uk" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #21 from richard at nildram dot co dot uk  2007-01-06 08:42 -------
Subject: Re:  [4.0/4.1 regression] internal consistency failure

"ebotcazou at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:
>> Eric asked me to weigh in here.  My only concern about a backport is Comment
>> #9, which suggests that the patch didn't work.  I'm assuming that since we're
>> all talking about backporting it, that comment was mistaken?  If indeed there
>> are no known problems, I think it's reasonable to put this on 4.1.
>
> Thanks Mark.  It seems that a whole new class of internal consistency failures
> due to the mishandling of REG_NOTEs in the combiner appeared in 4.1.x (for
> example rtl-optimization/28243 and the blocked rtl-optimization/29329) and up.
> Richard's patch is the most generic fix available as of today, so backporting
> it or not to the 4.1.x branch has cascading effects on the other PRs.  Maybe
> the problem reported in comment #9 is another variant.
>
> Richard, are you still ready to backport it?  If so, I can revert my patch for
> rtl-optimization/28243 right now to make things easier.

Yup, I'm still ready to backport it if the consensus is that
the patch is OK for 4.1.  I see from later comments that you
might be backporting it yourself, but the offer still stands
if you haven't started yet.

Richard


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514