[llvm-bugs] [Bug 47419] New: teams construct in implicit parallel has incorrect number of threads/teams

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=47419

            Bug ID: 47419
           Summary: teams construct in implicit parallel has incorrect
                    number of threads/teams
           Product: OpenMP
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Runtime Library
          Assignee: unassignedbugs at nondot.org
          Reporter: jacob.weightman at hpe.com
                CC: llvm-bugs at lists.llvm.org

Consider the following program:
```
#include <omp.h>
#include <stdio.h>

int main(void) {
    printf("num_teams = %d\n", omp_get_num_teams());
    printf("num_threads = %d\n", omp_get_num_threads());

    #pragma omp teams num_teams(4)
    {
        if(omp_get_team_num() == 0) {
            printf("num_teams = %d\n", omp_get_num_teams());
            printf("num_threads = %d\n", omp_get_num_threads());
        }
        printf("team: %d; thread: %d\n",
               omp_get_team_num(),
               omp_get_thread_num());
    }
}
```

At present, Clang prints out (up to the ordering of the print statements):
```
num_teams = 1
num_threads = 1
num_teams = 4
num_threads = 12
team: 0; thread: 0
team: 1; thread: 0
team: 2; thread: 0
team: 3; thread: 0
```

The OpenMP 5.0 spec (section 2.7) states that
> The teams construct creates a league of initial teams and the initial thread in each team executes the region.

and (section 3.2.2):
> The omp_get_num_threads routine returns the number of threads in the current team.

The latter print statements indicate that the num_teams clause is respected,
and there is 1 thread per team. Therefore, one should expect that
omp_get_num_threads should return 1 inside of the teams region.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20200904/372b3ace/attachment-0001.html>