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From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/45623] [4.5/4.6 Regression] GCC 4.5.[01] breaks our ffi on Linux64. ABI break? Date: Wed, 15 Sep 2010 12:31:00 -0000 [thread overview] Message-ID: <20100915123116.29537.qmail@sourceware.org> (raw) In-Reply-To: <bug-45623-18333@http.gcc.gnu.org/bugzilla/> ------- Comment #14 from rguenth at gcc dot gnu dot org 2010-09-15 12:31 ------- You are accessing a pointer of type char *s1 via an lvalue of type void * (*data). Or speaking in C++, you are accessing an object of dynamic type void * (stored to via *data) by an lvalue of type char * (s1). Thus your testcase invokes undefined behavior. That it is miscompiled at -O1 is a bug. With GCC 4.6 we now assign the same alias-set to all pointers, hiding this issue. data_4 is a non-pointer variable,ignoring constraint:*data_4 = s2.1_5 data_4, points-to vars: { } oops. I will have a look at the points-to bug. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot |dot org |org Status|NEW |ASSIGNED Component|target |tree-optimization Keywords| |wrong-code Last reconfirmed|2010-09-15 12:16:05 |2010-09-15 12:31:16 date| | Summary|GCC 4.5.[01] breaks our ffi |[4.5/4.6 Regression] GCC |on Linux64. ABI break? |4.5.[01] breaks our ffi on | |Linux64. ABI break? Target Milestone|--- |4.5.2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45623
next prev parent reply other threads:[~2010-09-15 12:31 UTC|newest] Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-09-09 21:45 [Bug regression/45623] New: " tglek at mozilla dot com 2010-09-09 22:03 ` [Bug target/45623] " dwitte at mozilla dot com 2010-09-09 22:18 ` pinskia at gcc dot gnu dot org 2010-09-10 0:38 ` hjl dot tools at gmail dot com 2010-09-10 0:46 ` dwitte at mozilla dot com 2010-09-10 0:52 ` hjl dot tools at gmail dot com 2010-09-10 1:41 ` pinskia at gcc dot gnu dot org 2010-09-10 2:37 ` tglek at mozilla dot com 2010-09-10 2:57 ` hjl dot tools at gmail dot com 2010-09-15 11:45 ` mh+gcc at glandium dot org 2010-09-15 11:53 ` mh+gcc at glandium dot org 2010-09-15 12:05 ` mh+gcc at glandium dot org 2010-09-15 12:12 ` mh+gcc at glandium dot org 2010-09-15 12:16 ` rguenth at gcc dot gnu dot org 2010-09-15 12:31 ` rguenth at gcc dot gnu dot org [this message] 2010-09-15 12:47 ` [Bug tree-optimization/45623] [4.5/4.6 Regression] " mh+gcc at glandium dot org 2010-09-15 12:52 ` mh+gcc at glandium dot org 2010-09-15 13:04 ` rguenth at gcc dot gnu dot org 2010-09-15 13:14 ` mh+gcc at glandium dot org 2010-09-15 13:25 ` rguenth at gcc dot gnu dot org 2010-09-15 13:41 ` mh+gcc at glandium dot org 2010-09-15 13:50 ` rguenth at gcc dot gnu dot org 2010-09-15 13:52 ` mh+gcc at glandium dot org 2010-09-15 13:56 ` rguenther at suse dot de 2010-09-15 13:59 ` rguenth at gcc dot gnu dot org 2010-09-15 14:01 ` mh+gcc at glandium dot org 2010-09-16 11:06 ` rguenth at gcc dot gnu dot org 2010-09-16 11:07 ` [Bug tree-optimization/45623] [4.5 " rguenth at gcc dot gnu dot org 2010-09-17 9:09 ` rguenth at gcc dot gnu dot org 2010-09-20 8:34 ` rguenth at gcc dot gnu dot org 2010-09-20 8:34 ` rguenth at gcc dot gnu dot org
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