[Bug middle-end/53046] New: [4.8 Regression] New libstdc++ test failures

[Bug middle-end/53046] New: [4.8 Regression] New libstdc++ test failures

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

             Bug #: 53046
           Summary: [4.8 Regression] New libstdc++ test failures
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hjl.tools@gmail.com
                CC: areg.melikadamyan@gmail.com


On Linux/x86-64, revision 186596 gave

FAIL: 23_containers/bitset/operations/constexpr-2.cc (test for excess errors)
FAIL: 25_algorithms/stable_partition/mem_check.cc execution test
FAIL: 25_algorithms/stable_sort/mem_check.cc execution test

Revision 186588 is OK.

[Bug middle-end/53046] [4.8 Regression] New libstdc++ test failures

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hp at gcc dot gnu.org

--- Comment #1 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-04-20 02:30:17 UTC ---
Noticed the mem_check.cc ones (not the constexpr-2.cc one) for cris-elf too,
186591:186599.

[Bug middle-end/53046] [4.8 Regression] New libstdc++ test failures

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-04-20
   Target Milestone|---                         |4.8.0
     Ever Confirmed|0                           |1

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-04-20 09:21:32 UTC ---
Confirmed.

[Bug middle-end/53046] [4.8 Regression] New libstdc++ test failures

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu.org

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> 2012-04-21 22:42:18 UTC ---
It is caused by revision 186592:

http://gcc.gnu.org/ml/gcc-cvs/2012-04/msg00543.html

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |testsuite

--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-04-23 09:17:10 UTC ---
I belive those are likely out-of-bound accesses in the testcases.

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |chris at bubblescope dot
                   |                            |net

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-04-23 09:37:08 UTC ---
Chris, can you have a look to the mem_check tests?

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[chris at bubblescope dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

--- Comment #6 from Chris Jefferson <chris at bubblescope dot net> 2012-04-23 09:44:11 UTC ---
Yes, will check.

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[chris at bubblescope dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

--- Comment #7 from Chris Jefferson <chris at bubblescope dot net> 2012-04-23 09:57:12 UTC ---
While I haven't yet got a recent copy of gcc trunk compiled, it does indeed
look like an out-of-bounds error, but just a 'testsuite' problem.

At the top of both mem_check tests as a 'const int A[]' array with 29 elements,
which we read 30 elements of. If doesn't matter what the extra element is, we
just want an array of any 30 integers, which is why this hasn't caused problems
before.

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |paolo.carlini at oracle dot
                   |gnu.org                     |com

--- Comment #8 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-04-23 10:36:28 UTC ---
Oops, thanks a lot Chris!! I'll do the change.

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[chris at bubblescope dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

--- Comment #9 from Chris Jefferson <chris at bubblescope dot net> 2012-04-23 10:54:57 UTC ---
Looking at the output of -fdump-tree-all, it looks like the compiler optimises
the loop which accesses an array out of bounds to:

while(true);

Is this expected behaviour? That seems like terrible output for every
situation...

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

--- Comment #10 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-04-23 11:17:34 UTC ---
Author: paolo
Date: Mon Apr 23 11:17:28 2012
New Revision: 186701

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186701
Log:
2012-04-23  Chris Jefferson  <chris@bubblescope.net>

    PR testsuite/53046
    * testsuite/25_algorithms/stable_partition/mem_check.cc: Fix size
    of array A.
    * testsuite/25_algorithms/stable_sort/mem_check.cc: Likewise.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/testsuite/25_algorithms/stable_partition/mem_check.cc
    trunk/libstdc++-v3/testsuite/25_algorithms/stable_sort/mem_check.cc

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #11 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-04-23 11:20:26 UTC ---
Done.

(Chris, if you are interested in discussing optimizer issues, please move the
discussion to the mailing list!)

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

--- Comment #12 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-04-23 11:42:28 UTC ---
(In reply to comment #9)
> Looking at the output of -fdump-tree-all, it looks like the compiler optimises
> the loop which accesses an array out of bounds to:
> 
> while(true);
> 
> Is this expected behaviour? That seems like terrible output for every
> situation...

It's similar to other cases where undefined behavior leads to the GIGO
principle.  Other cases being a simple integer overflow inside a loop
(not even necessarily the loop induction variable itself).

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

--- Comment #13 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-04-23 15:24:49 UTC ---
Author: paolo
Date: Mon Apr 23 15:24:44 2012
New Revision: 186713

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186713
Log:
2012-04-23  Chris Jefferson  <chris@bubblescope.net>

    PR testsuite/53046
    * testsuite/25_algorithms/stable_partition/mem_check.cc: Fix size
    of array A.
    * testsuite/25_algorithms/stable_sort/mem_check.cc: Likewise.

Modified:
    branches/gcc-4_7-branch/libstdc++-v3/ChangeLog
   
branches/gcc-4_7-branch/libstdc++-v3/testsuite/25_algorithms/stable_partition/mem_check.cc
   
branches/gcc-4_7-branch/libstdc++-v3/testsuite/25_algorithms/stable_sort/mem_check.cc

[Bug testsuite/53046] [4.8 Regression] New libstdc++ test failures

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53046

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.0                       |4.7.1