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Re: [Bug tree-optimization/22630] [4.1 Regression] vrp produceswrong code
- From: ja2morri at csclub dot uwaterloo dot ca (James A. Morrison)
- To: law at redhat dot com
- Cc: gcc-patches at gcc dot gnu dot org, gcc-bugzilla at gcc dot gnu dot org,law at gcc dot gnu dot org
- Date: Wed, 27 Jul 2005 12:34:17 -0400
- Subject: Re: [Bug tree-optimization/22630] [4.1 Regression] vrp produceswrong code
- References: <20050723162927.22630.belyshev@depni.sinp.msu.ru><20050726200636.17919.qmail@sourceware.org><1122481180.8352.175.camel@localhost.localdomain>
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?
--
Thanks,
Jim
http://www.csclub.uwaterloo.ca/~ja2morri/
http://phython.blogspot.com
http://open.nit.ca/wiki/?page=jim