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[Bug tree-optimization/22630] [4.1 Regression] vrp produces wrong code
- From: "ja2morri at csclub dot uwaterloo dot ca" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 27 Jul 2005 16:34:45 -0000
- Subject: [Bug tree-optimization/22630] [4.1 Regression] vrp produces wrong code
- References: <20050723162927.22630.belyshev@depni.sinp.msu.ru>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- 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?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22630