[Bug middle-end/54261] New: reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[Bug middle-end/54261] New: reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

             Bug #: 54261
           Summary: reverse sync/atomic operators when only
                    sync_compare_and_swap_optab libfuncs implemented
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hp@gcc.gnu.org
            Target: cris*-*-linux-gnu


If a target implements atomics by only setting sync_compare_and_swap_optab
libfuncs (see cris.c:cris_init_libfuncs), a path less travelled is used, on
which a bug lies, causing sync/atomic operators to be implemented with the
reverse operator, e.g. minus instead of plus.  See test-case to be added and
patch to be posted and referenced.

[Bug middle-end/54261] reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-08-14
         AssignedTo|unassigned at gcc dot       |hp at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-08-14 19:55:02 UTC ---
Created attachment 28017
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28017
test-case suitable as gcc.dg/torture/pr54261-1.c

The lack of non-cas_int test-cases except in the libstdc++ testsuite helped
this trivial bug survive a test-run.

[Bug middle-end/54261] reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

[Bug middle-end/54261] reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

--- Comment #2 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-08-16 22:03:39 UTC ---
Author: hp
Date: Thu Aug 16 22:03:33 2012
New Revision: 190454

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190454
Log:
    PR middle-end/54261
    * optabs.c (expand_atomic_fetch_op): Save and restore code when
    retrying after failed attempt.

Modified:
    trunk/gcc/ChangeLog

[Bug middle-end/54261] reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

--- Comment #3 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-08-16 22:05:37 UTC ---
Author: hp
Date: Thu Aug 16 22:05:32 2012
New Revision: 190455

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190455
Log:
    PR middle-end/54261
    * gcc.dg/torture/pr54261-1.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr54261-1.c
Modified:
    trunk/gcc/testsuite/ChangeLog

[Bug middle-end/54261] reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

--- Comment #4 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-08-17 00:18:42 UTC ---
Author: hp
Date: Fri Aug 17 00:18:35 2012
New Revision: 190463

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190463
Log:
    PR middle-end/54261
    * optabs.c (expand_atomic_fetch_op): Save and restore code when
    retrying after failed attempt.

Modified:
    trunk/gcc/optabs.c

[Bug middle-end/54261] reverse sync/atomic operators when only sync_compare_and_swap_optab libfuncs implemented

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54261

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

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

--- Comment #5 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-08-17 00:19:57 UTC ---
fixed for 4.8