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Re: [lno] some cleanups for scev
- From: kaih at khms dot westfalen dot de (Kai Henningsen)
- To: gcc-patches at gcc dot gnu dot org
- Date: 02 May 2004 09:32:00 +0200
- Subject: Re: [lno] some cleanups for scev
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- Organization: Organisation? Me?! Are you kidding?
- References: <20040415145418.GA1950@cri.ensmp.fr> <20040415161158.GA2679@cri.ensmp.fr> <20040415202336.GA17683@atrey.karlin.mff.cuni.cz> <20040415202336.GA17683@atrey.karlin.mff.cuni.cz> <20040420154119.GA3926@cri.ensmp.fr>
sebastian.pop@cri.ensmp.fr (Sebastian Pop) wrote on 20.04.04 in <20040420154119.GA3926@cri.ensmp.fr>:
> As Zdenek has pointed out privately, the interval arithmetic is
> erroneous when overflows occur.
>
> Because the result can be of the form [-127, -10] U [0, 128] this is
> no longer an interval, and consequently the best solution that I see
> is to just answer chrec_top when an overflow occurs.
In the case above, wouldn't [-127, 128] be a sufficiently correct answer?
MfG Kai