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From: "law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/22630] [4.1 Regression] vrp produces wrong code
Date: Wed, 27 Jul 2005 17:06:00 -0000 [thread overview]
Message-ID: <20050727165554.26922.qmail@sourceware.org> (raw)
In-Reply-To: <20050723162927.22630.belyshev@depni.sinp.msu.ru>
------- Additional Comments From law at redhat dot com 2005-07-27 16:55 -------
Subject: Re: [4.1 Regression] vrp produces
wrong code
On Wed, 2005-07-27 at 16:34 +0000, ja2morri at csclub dot uwaterloo dot
ca wrote:
> ------- Additional Comments From ja2morri at csclub dot uwaterloo dot ca 2005-07-27 16:34 -------
> Subject: Re: [4.1 Regression] vrp produces
> wrong code
>
>
> Jeffrey A Law <law@redhat.com> writes:
>
> > The underlying problem here is the code to meet a VR_ANTI_RANGE and
> > a VR_RANGE does not intersect the equivalence sets. This in turn
> > causes the VRP code to incorrectly evaluate a conditional. It's
> > all downhill after that.
> >
> > While investigating this problem I also noticed that the vrp_meet
> > code does not properly handle intersecting the equivalence sets
> > when vr0 has a set, but vr1 does not (their intersection is the
> > null set of course). This patch fixes that oversight as well.
> >
> > Bootstrapped and regression tested on i686-pc-linux-gnu.
> >
> > jeff
>
> You added 3 bitmap_clear calls here, do you have any testcases that
> exercise this code?
No, but the code is clearly wrong by inspection.
jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22630
prev parent reply other threads:[~2005-07-27 16:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-23 16:35 [Bug tree-optimization/22630] New: " belyshev at depni dot sinp dot msu dot ru
2005-07-23 16:36 ` [Bug tree-optimization/22630] " belyshev at depni dot sinp dot msu dot ru
2005-07-23 16:38 ` [Bug tree-optimization/22630] [4.1 Regression] " pinskia at gcc dot gnu dot org
2005-07-23 17:07 ` pinskia at gcc dot gnu dot org
2005-07-25 0:43 ` phython at gcc dot gnu dot org
2005-07-26 20:06 ` law at redhat dot com
2005-07-27 16:22 ` law at redhat dot com
2005-07-27 16:36 ` ja2morri at csclub dot uwaterloo dot ca
2005-07-27 17:06 ` law at redhat dot com [this message]
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