[Bug libgomp/40494] New: omp for loop with guided schedule fails to terminate in certain cases

["per at bitempire dot com" <gcc-bugzilla@gcc.gnu.org>]

The following loop, which seems valid according to the OpenMP specification
v2.5 and 3.0 fails to terminate:

int x;
#pragma omp parallel for schedule(guided)
for(x = 3; x < 478; x += 2) {
  ...
}

I've tested with two and eight threads and different chunksizes, with the same
non-termination result. Changing the upper bound to 477, however, makes the
loop terminate, which leads me to belive this is an issue in the GNU OpenMP
runtime library.

I have confirmed that the problems exists in 4.2, 4.3 and 4.5 (trunk,
19-06-09). To me,  bug 35625 seems somewhat similar but was supposedly fixed in
4.3.

/Per


-- 
           Summary: omp for loop with guided schedule fails to terminate in
                    certain cases
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgomp
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: per at bitempire dot com
 GCC build triplet: i686-pc-linux
  GCC host triplet: i686-pc-linux
GCC target triplet: i686-pc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40494