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[Bug rtl-optimization/20367] alias analysis doesn't take into account that variables that haven't their address taken can't alias arbitrary MEMs
- From: "amylaar at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Mar 2005 20:01:29 -0000
- Subject: [Bug rtl-optimization/20367] alias analysis doesn't take into account that variables that haven't their address taken can't alias arbitrary MEMs
- References: <20050307194707.20367.amylaar@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From amylaar at gcc dot gnu dot org 2005-03-07 20:01 -------
Created an attachment (id=8353)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8353&action=view)
patch against 3.4
The previous patch had the problem that the non-existence of a MEM_EXPR was
taken
to mean that no static variable is involved. This updated patch uses a
MEM_EXPR with the new special node unspecified_indirect_ref_node to indicate
that no
static variable is involved. Thus, when two MEMs are merged and thus loose
their MEM_EXPR, the optimization should still be safe.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20367