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[Bug tree-optimization/27865] [4.2 Regression] tree check failure building FreePOOMA
- From: "rakdver at atrey dot karlin dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 5 Jun 2006 11:04:35 -0000
- Subject: [Bug tree-optimization/27865] [4.2 Regression] tree check failure building FreePOOMA
- References: <bug-27865-4503@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #6 from rakdver at atrey dot karlin dot mff dot cuni dot cz 2006-06-05 11:04 -------
Subject: Re: [4.2 Regression] tree check failure building FreePOOMA
> Someone who understands SCEV really needs to fix it.
On this particular piece of code SCEV seems to behave just fine; you ask
for the evolution of a pointer, and then use TYPE_MAX_VALUE on its type --
that's not going to work.
> It's been a consistent
> source of problems for VRP -- whether it's giving us bogus ranges (ranges
> outside the given type) or claiming variables do not wrap when in fact they do
> wrap (IIRC there's still an outstanding PR due to this problem).
>
> If someone were to fix the SCEV problem touched by pr 25900, then the offending
> VRP code could be eliminated.
I will have a look.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27865