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[Bug tree-optimization/33136] [4.1/4.2/4.3 Regression] wrong code due to alias with allocation in loop
- From: "jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 5 Sep 2007 05:46:52 -0000
- Subject: [Bug tree-optimization/33136] [4.1/4.2/4.3 Regression] wrong code due to alias with allocation in loop
- References: <bug-33136-12956@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #26 from jakub at gcc dot gnu dot org 2007-09-05 05:46 -------
This is just one bug, present in GCC 4.1 and onwards, no need to have
several bug ids.
tree-ssa-alias.c just uses ipa_type_escape_field_does_not_clobber_p
incorrectly, it asks an unrelated question and based on the answer decides
if things can or can't alias. There are testcases where this bug exhibits
only in some gcc versions (e.g.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33136#c7 ), because it depends
on what exactly other optimization passes do, and other testcases, like #c8,
which fail in all 4.1+ GCCs.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33136