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[Bug tree-optimization/33099] [4.2 Regression] Scalar evolutions confusing VRP with pointer values that wrap around
- From: "dnovillo at google dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 17 Aug 2007 20:37:53 -0000
- Subject: [Bug tree-optimization/33099] [4.2 Regression] Scalar evolutions confusing VRP with pointer values that wrap around
- References: <bug-33099-91@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from dnovillo at google dot com 2007-08-17 20:37 -------
Subject: Re: [4.2 Regression] Scalar evolutions
confusing VRP with pointer values that wrap around
On 8/17/07 4:34 PM, pinskia at gcc dot gnu dot org wrote:
> ------- Comment #4 from pinskia at gcc dot gnu dot org 2007-08-17 20:34 -------
> Oh you are correct but this still worked in 4.1.1 though, I have not looked
> into what changed between 4.1.1 and 4.2.0 with respect of scev yet.
Since you are looking, two things to check for: (1) IL representation
for the pointer subtraction, and (2) SCEV may have returned an unknown
chrec back in 4.1. Or maybe we still didn't consider pointers to not-wrap.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33099