[Bug tree-optimization/52242] New: [4.7 regression] libgomp.c/atomic-2.c failure on s390x

[Bug tree-optimization/52242] New: [4.7 regression] libgomp.c/atomic-2.c failure on s390x

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

             Bug #: 52242
           Summary: [4.7 regression] libgomp.c/atomic-2.c failure on s390x
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: krebbel@gcc.gnu.org


181748        rth       /* ??? Assume BIGGEST_ALIGNMENT *is* aligned.  */
181748        rth       if (exact_log2 (align) >= index
181748        rth       || align * BITS_PER_UNIT >= BIGGEST_ALIGNMENT)

That broke the atomic-2.c libgomp testcase on s390x. We have
BIGGEST_ALIGNMENT of 64. A 128 bit long double does not need to be
aligned better than 64 bit in memory. However, the 128bit compare and
swap instruction we have requires the operands to be naturally
aligned. In the testcase a compare and swap double instruction is used
on a long double value which is only 8 byte aligned in memory.

[Bug tree-optimization/52242] [4.7 regression] libgomp.c/atomic-2.c failure on s390x

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

Andreas Krebbel <krebbel at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |s390x-ibm-linux
           Priority|P3                          |P2
               Host|                            |s390x-ibm-linux
              Build|                            |s390x-ibm-linux

[Bug tree-optimization/52242] [4.7 regression] libgomp.c/atomic-2.c failure on s390x

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rth at gcc dot gnu.org
   Target Milestone|---                         |4.7.0

[Bug tree-optimization/52242] [4.7/4.8 regression] libgomp.c/atomic-2.c failure on s390x

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-03-05
         AssignedTo|unassigned at gcc dot       |rth at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Henderson <rth at gcc dot gnu.org> 2012-03-05 19:13:10 UTC ---
Mine.

[Bug tree-optimization/52242] [4.7/4.8 regression] libgomp.c/atomic-2.c failure on s390x

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

--- Comment #2 from Richard Henderson <rth at gcc dot gnu.org> 2012-03-05 19:52:19 UTC ---
Author: rth
Date: Mon Mar  5 19:52:08 2012
New Revision: 184955

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=184955
Log:
PR tree-opt/52242
    Revert: 2011-11-26  Richard Henderson  <rth@redhat.com>
    * omp-low.c (expand_omp_atomic): Assume anything aligned to
    BIGGEST_ALIGNMENT is aligned.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/omp-low.c

[Bug tree-optimization/52242] [4.7/4.8 regression] libgomp.c/atomic-2.c failure on s390x

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

--- Comment #3 from Richard Henderson <rth at gcc dot gnu.org> 2012-03-05 19:54:02 UTC ---
Author: rth
Date: Mon Mar  5 19:53:54 2012
New Revision: 184956

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=184956
Log:
PR tree-opt/52242
    Revert: 2011-11-26  Richard Henderson  <rth@redhat.com>
    * omp-low.c (expand_omp_atomic): Assume anything aligned to
    BIGGEST_ALIGNMENT is aligned.

Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/omp-low.c

[Bug tree-optimization/52242] [4.7/4.8 regression] libgomp.c/atomic-2.c failure on s390x

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52242

Richard Henderson <rth at gcc dot gnu.org> changed:

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

--- Comment #4 from Richard Henderson <rth at gcc dot gnu.org> 2012-03-05 20:03:52 UTC ---
Fixed.