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Re: Fix tree-optimization/20920
- From: Jeffrey A Law <law at redhat dot com>
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org, gcc-bugs at gcc dot gnu dot org
- Date: Mon, 11 Apr 2005 13:22:40 -0600
- Subject: Re: Fix tree-optimization/20920
- Organization: Red Hat, Inc
- References: <20050410032749.GA900@topo.toronto.redhat.com>
- Reply-to: law at redhat dot com
On Sat, 2005-04-09 at 23:27 -0400, Diego Novillo wrote:
> Sigh. Another SSA_NAME flowing through EH edges getting in the
> I'm starting to think that it would be much better to make these
> SSA_NAME_OCCURS_IN_ABNORMAL_PHI into virtuals. We would avoid
> all the monkeying around that optimizers have to do. It would
> involve a bit of trickery because we only detect them when they
> first go into SSA form, but it's doable. Comments from EH folks?
I think that would have a rather bad effect on C++ and Java code.
One of the nice things about the current approach is that it is very
fine grained -- ie, the flag bit appears on SSA_NAMEs and thus has
a relatively limited affect on optimization.
Your approach would in effect penalize all other instances of a _DECL
just because one instance happened to flow through an EH edge.