[Bug libgomp/35881] New: OMP atypical results for omp_get_max_threads

[Bug libgomp/35881] New: OMP atypical results for omp_get_max_threads

[jv244 at cam dot ac dot uk]

The following test program returns 1 for omp_get_max_threads in a parallel
region. This is different from what I get with three other compilers, and hence
somewhat unexpected. Is this correct, and if so, should it be the default?

> gfortran -v
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: /data03/vondele/gcc_4_3_0_release/gcc-4.3.0/configure
--prefix=/ext/software/64/gfortran-suite/gcc-4.3.0
--enable-languages=c,c++,fortran
Thread model: posix
gcc version 4.3.0 (GCC)

SUBROUTINE TEST()
   IMPLICIT NONE
   INTEGER :: ithread,nthread,mthread
!$ INTEGER :: omp_get_thread_num, omp_get_max_threads, omp_get_num_threads

   ithread=0
   nthread=1
   mthread=1

!$ nthread=omp_get_max_threads()
   write(6,*) ithread,nthread,mthread

!$OMP PARALLEL PRIVATE(ithread,nthread,mthread)
!$ nthread=omp_get_max_threads()
!$ mthread=omp_get_num_threads()
!$ ithread=omp_get_thread_num()
!$OMP CRITICAL
   write(6,*) ithread,nthread,mthread
!$OMP END CRITICAL
!$OMP END PARALLEL

END SUBROUTINE TEST

CALL TEST()

END


IBM:
vondele@blanc161:~> xlf90_r -qsuffix=f=f90 -O3 -qsmp=omp test.f90
** test   === End of Compilation 1 ===
** _main   === End of Compilation 2 ===
1501-510  Compilation successful for file test.f90.
vondele@blanc161:~> ./a.out
 0 4 1
 0 4 4
 1 4 4
 3 4 4
 2 4 4

vondele@pcihopt3:/data03/vondele/openmp> pgf90 -openmp test.f90
vondele@pcihopt3:/data03/vondele/openmp> ./a.out
           0           4           1
           0           4           4
           1           4           4
           2           4           4
           3           4           4

vondele@pcihopt3:/data03/vondele/openmp> ifort -O0 -openmp test.f90
test.f90(13): (col. 7) remark: OpenMP DEFINED REGION WAS PARALLELIZED.
vondele@pcihopt3:/data03/vondele/openmp> ./a.out
           0           4           1
           0           4           4
           1           4           4
           2           4           4
           3           4           4

vondele@pcihopt3:/data03/vondele/openmp> gfortran  -O0 -fopenmp test.f90
vondele@pcihopt3:/data03/vondele/openmp> ./a.out
           0           4           1
           0           1           4
           1           1           4
           2           1           4
           3           1           4


-- 
           Summary: OMP atypical results for omp_get_max_threads
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgomp
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jv244 at cam dot ac dot uk


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35881

[Bug libgomp/35881] OMP atypical results for omp_get_max_threads

[jv244 at cam dot ac dot uk]

------- Comment #1 from jv244 at cam dot ac dot uk  2008-04-09 08:07 -------
reading a bit more, this seems a real bug. 
Can this be fixed for 4.3, pretty please ?


-- 

jv244 at cam dot ac dot uk changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
            Summary|OMP atypical results for    |OMP atypical results for
                   |omp_get_max_threads         |omp_get_max_threads


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35881

[Bug libgomp/35881] OMP wrong results for omp_get_max_threads

[jv244 at cam dot ac dot uk]

------- Comment #2 from jv244 at cam dot ac dot uk  2008-04-09 10:58 -------
also confirmed for trunk


-- 

jv244 at cam dot ac dot uk changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|4.2.3 4.3.0                 |4.2.3 4.3.0 4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35881

[Bug libgomp/35881] OMP wrong results for omp_get_max_threads

[jv244 at cam dot ac dot uk]

------- Comment #3 from jv244 at cam dot ac dot uk  2008-04-09 13:31 -------
I decided to ask, and maybe it is correct anyway, even though I have not fully
followed the bit on 'nthreads-var'

http://www.openmp.org/forum/viewtopic.php?f=3&t=100


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35881

[Bug libgomp/35881] OMP wrong results for omp_get_max_threads

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2008-06-11 06:48 -------
Fixed on the trunk as part of the OpenMP 3.0 support.


-- 

jakub at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35881