[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #12 from Martin Jambor jamborm at gcc dot gnu.org 2010-10-11 18:45:28 UTC --- Author: jamborm Date: Mon Oct 11 18:45:23 2010 New Revision: 165327 URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=165327 Log: 2010-10-11 Martin Jambor mjam...@suse.cz PR middle-end/45699 * gimple-fold.c (gimple_fold_obj_type_ref_known_binfo): Choose among thunks. * testsuite/g++.dg/torture/pr45699.C: New test. * testsuite/g++.dg/otr-fold-1.C: Adjusted. * testsuite/g++.dg/otr-fold-1.C: Likewise. Added: trunk/gcc/testsuite/g++.dg/torture/pr45699.C Modified: trunk/gcc/ChangeLog trunk/gcc/gimple-fold.c trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/g++.dg/otr-fold-1.C trunk/gcc/testsuite/g++.dg/otr-fold-2.C
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 Martin Jambor jamborm at gcc dot gnu.org changed: What|Removed |Added Status|NEW |RESOLVED Resolution||FIXED --- Comment #13 from Martin Jambor jamborm at gcc dot gnu.org 2010-10-11 18:46:34 UTC --- Fixed.
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #6 from Martin Jambor jamborm at gcc dot gnu.org 2010-10-08 12:12:34 UTC --- The problem seems to be the only folding of OBJ_TYPE_REF we do and which comes from a (copy) constructor. So I assume this is the same issue as PR 45934.
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #7 from Martin Jambor jamborm at gcc dot gnu.org 2010-10-08 14:40:41 UTC --- Please disregard the previous comment, I saw what I wanted to see and not what was actually there. But it is true that avoiding the only O_T_R folding avoids the segfault. But so far I see nothing wrong with that devirtualization... I will keep staring at it for a bit longer.
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #8 from bredelin at ucla dot edu 2010-10-08 15:58:49 UTC --- When you say segfault, I presume you mean abort? When I use the debugger, the problem appears to be in the call to new Parameters(*P); On x86_64, the problem occurs as follows: (x86_32 is different) In the copy constructor, Parameters::SuperModel2 is constructed OK. Then the copy constructor for Parameters::Probability_Model is called, which calls the copy constructor for Probability_Model::Model2, which calls the copy constructor for Model2::vectordouble. In the (synthesized) copy constructor vectordouble::vectordouble(const vectordouble __x), the debugger claims that this and __x are both optimized out, and won't let me inspect anything. The SIGABORT actually occurs because the __x has a __x.size() of 18446726482060379005. It should have a size of 0. (I can't call __x.size(), but I can access __n, which is initialized from __x.size()).
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #9 from bredelin at ucla dot edu 2010-10-08 16:37:15 UTC --- On x86_32, the problem occurs somewhat differently. All I did differently is add -m32. It seems that on x86_32, the copy constructor vectorint::vectorint(const vector __x) for SuperModel2::object fails, whereas it succeeded on x86_64. The values for this and __x are not optimized out for SuperModel2::object, so they can be inspected. The values for __x appear to be crazy. This leads to a large __n, and thus another abort because of an attempt to allocate too much memory. (__n should be 0). The error may be caused by the fact that __x points to the wrong memory location (0xd4a0, instead of the correct value 0xd484). I think the location of __x is wrong on x86_64 also, but it just so happens on x86_64 that __x._M_finish - __x._M_start is 0 for the wrong location of __x, whereas on x86_32 it does not happen to be 0. Does this help any?
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #10 from Martin Jambor jamborm at gcc dot gnu.org 2010-10-08 16:51:19 UTC --- I think I know what is going on. BINFO_VIRTUALS of the BINFO describing Probability_Model within Parameters pint to a wring thunk of the method Parameters:clone(). Therefore when the call is devirtualized, the this parameter is not adjusted to point to the whole Ptr object and points only to the part representing the Probability_Model ancestor. And so all references to the fields of the object just load garbage.
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #11 from Martin Jambor jamborm at gcc dot gnu.org 2010-10-08 17:57:11 UTC --- Created attachment 21998 -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=21998 proposed patch But fortunately BINFOs contain the delta and so we can find the appropriate thunk in the call graph. I'm attaching an untested proposed fix which seems to work on the testcase. Obviously I need to clean it up a little bit and will also try to make a simple testcase.
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 --- Comment #5 from bredelin at ucla dot edu 2010-10-06 15:46:08 UTC --- This bug still existed as of Oct 4, 2010. gcc version 4.6.0 20101004 (experimental) [trunk revision 164952] (Ubuntu 20101004-0ubuntu1) After this bug is fixed, I'll be able to do some more testing of 4.6 for a large c++ program.
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699 Richard Guenther rguenth at gcc dot gnu.org changed: What|Removed |Added Keywords||wrong-code Priority|P3 |P1
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
-- rguenth at gcc dot gnu dot org changed: What|Removed |Added Summary|Incorrect copy constructor |[4.6 Regression] Incorrect |generated with -O |copy constructor generated ||with -O Target Milestone|--- |4.6.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
--- Comment #3 from hjl dot tools at gmail dot com 2010-09-17 14:29 --- It is caused by revision 159362: http://gcc.gnu.org/ml/gcc-cvs/2010-05/msg00414.html -- hjl dot tools at gmail dot com changed: What|Removed |Added CC||mjambor at suse dot cz http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
-- hjl dot tools at gmail dot com changed: What|Removed |Added Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 Last reconfirmed|-00-00 00:00:00 |2010-09-17 14:29:19 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699
[Bug middle-end/45699] [4.6 Regression] Incorrect copy constructor generated with -O
--- Comment #4 from jamborm at gcc dot gnu dot org 2010-09-17 14:39 --- I'll have a look at it but please be patient, my bug queue is rather long at the moment. -- jamborm at gcc dot gnu dot org changed: What|Removed |Added CC|mjambor at suse dot cz |jamborm at gcc dot gnu dot ||org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45699
