[Bug c++/57618] New: OpenMP atomic read and write are not sequentially consistent

[Bug c++/57618] New: OpenMP atomic read and write are not sequentially consistent

[nmm1 at cam dot ac.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57618

            Bug ID: 57618
           Summary: OpenMP atomic read and write are not sequentially
                    consistent
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nmm1 at cam dot ac.uk

See bug 57617 for the data and more description.  But the same program
finds that OpenMP atomic read and write are not sequentially consistent.
That will assuredly cause wrong answers when yer everage programmer
attempts to use them.

But should they be?  If you can decode any specification on this matter
from what OpenMP are pleased to call a standard, you are more intelligent
than I am.

So is this a bug, a gotcha or a feature?

[Bug c++/57618] OpenMP atomic read and write are not sequentially consistent

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57618

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|---                         |INVALID

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
No idea where you got that #pragma omp atomic should be sequentially
consistent, it is relaxed.  OpenMP 4.0 introduces seq_cst clause on all the
#pragma omp atomic {,update,read,write,capture} variants that makes it
sequentially consistent.