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Date: Wed, 16 Oct 2002 04:06:00 -0000
From: Jan Hubicka <jh@suse.cz>
To: Michael Matz <matz@suse.de>
Cc: Richard Henderson <rth@redhat.com>,
	Olivier Hainque <hainque@ACT-Europe.FR>, Jan Hubicka <jh@suse.cz>,
	gcc@gcc.gnu.org
Subject: Re: Question on fixup_abnormal_edges
Message-ID: <20021016093142.GH1083@kam.mff.cuni.cz>
References: <20021015230235.GM25225@redhat.com> <Pine.LNX.4.33.0210161051110.20702-100000@wotan.suse.de>
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> Hi,
> 
> On Tue, 15 Oct 2002, Richard Henderson wrote:
> 
> > > When using table driven EH, is it expected that possibly call clobbered hard
> > > registers get assigned to pseudos live across calls like in the case above ?
> >
> > Well, except for caller-save not being intelligent enough to
> > add the instruction to the edge, rather than directly after
> > the call instruction, everything would have worked out ok.
> 
> Erh.  You can't add insns on an abnormal edge, if it's critical.  I don't
> remember this very case, but is it guaranteed, that abcall/eh edges are
> not critical?

EH edges are abnormal and can be critical.  You can add insns to them,
if you update split_edge. (ie teoretically it is possible, but our
current framework can't deal with these)
It can be good idea to add code for that, as GCSE would be much happier
then too.

I think that EH kills registers anyway, so this is not problem.

I think problem is different.  The call with live register over is
noreturn, so there should really be no register alive at first place.
Hope I will find time to investigate this more at evening.

Honza