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[Bug tree-optimization/17400] out of SSA corruption
- From: "amacleod at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 10 Sep 2004 18:12:02 -0000
- Subject: [Bug tree-optimization/17400] out of SSA corruption
- References: <20040910153536.17400.steven@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From amacleod at redhat dot com 2004-09-10 18:11 -------
copyrename is making no attempt to prevent coalescing across abnormal edges.
There are a couple of issues to be resolved.
1 - abormal phi usage should be propagated to partitions when variables are merged
2 - dont coalesce partitions which are used in abnormnal phis,
3 - unless we are sure its safe to coalesce. Which we can be sure of in some
circumstances. (for instance, a single SSA_NAME occurence of a root variable)
3) May turn out to be an enhancement for 4.1
I'll provide a patch in a bit when I've thought about 3) a tiny bit more.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400