------- Comment #4 from law at redhat dot com 2006-04-11 05:56 -------
Subject: Re: [4.1/4.2 regression] ICE in
merge_alias_info
On Sat, 2006-04-08 at 23:16 +0000, pinskia at gcc dot gnu dot org wrote:
>
> ------- Comment #1 from pinskia at gcc dot gnu dot org 2006-04-08 23:16
> -------
> Confirmed, the ICE is during DOM.
As I mentioned in the PR notes, the problem is
tree-ssa-copy.c::may_propagate_copy allows copy propagations which
are rejected by merge_alias_info. Specifically it allows copy
propagating when the flow-sensitive alias information is not
compatible.
I'm not entirely sure the compatibility check in may_propagate_copy
and merge_alias_info is correct. It seems to me that we want to
verify that one is a subset of the other, not just that the two
objects have intersecting flow sensitive information. Someone
more familiar with this code should follow-up on that issue.
My patch merely makes the two routines consistent in how they handle
flow-sensitive alias information for copy propagations.
Bootstrapped and regression tested on i686-pc-linux-gnu.
------- Comment #5 from law at redhat dot com 2006-04-11 05:56 -------
Created an attachment (id=11241)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11241&action=view)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27087
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