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Re: cc register usage on i386/2.96
- To: Jan Hubicka <jh at suse dot cz>
- Subject: Re: cc register usage on i386/2.96
- From: Richard Henderson <rth at cygnus dot com>
- Date: Fri, 8 Sep 2000 10:55:33 -0700
- Cc: Andi Kleen <ak at suse dot de>, gcc-patches at gcc dot gnu dot org
- References: <20000828015105.C1077@atrey.karlin.mff.cuni.cz> <20000828020055.A29832@gruyere.muc.suse.de> <20000828132826.A18570@atrey.karlin.mff.cuni.cz> <20000828144101.C28813@cygnus.com> <20000829115751.E1368@atrey.karlin.mff.cuni.cz> <20000829093258.A4330@cygnus.com> <20000908143222.A10112@atrey.karlin.mff.cuni.cz>
On Fri, Sep 08, 2000 at 02:32:22PM +0200, Jan Hubicka wrote:
> But thinks don't work as expected and the overflow bit is set incorrectly.
> It seems to me, that overflow is not set properly even for add/sub
> instructions and thus we should disable the CCmode version of the patterns...
How irritating. The thing is, I can't figure why setg tests
the overflow flag at all. Why doesn't it test zf==0 && sf==0?
Well, a similar test with subtract does seem to work, so you
only need to diable CCmode add.