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[openmp][tests] Fix bug63197.c (#183508)

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#183269 tried to fix the test, but the test can still randomly fail. The
OpenMP spec does not prevent the runtime to chose a smaller team size
than returned from omp_max_threads() for the second parallel region.

Using a larger value than `omp_max_threads()` in a `num_threads` clause
is valid OpenMP code. With a correct OpenMP implementation, the
team-size of the second parallel region must still be smaller or equal
the value returned from `omp_max_threads()`.
This commit is contained in:
Joachim 2026-02-26 17:26:47 +01:00 committed by GitHub
parent 8d23abe415
commit d44e417945
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1 changed files with 9 additions and 3 deletions
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openmp/runtime/test/parallel/bug63197.c
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@ -3,16 +3,22 @@
#include <omp.h>
#include <stdio.h>
/* This code tests that state pushed for the num_threads clause does not
reach the next parallel region. omp_get_max_threads() + 1 can never
be chosen as team size for the second parallel and could only be the
result of some left-over state from the first parallel.
*/
int main(int argc, char *argv[]) {
unsigned N = omp_get_max_threads() - 1;
#pragma omp parallel num_threads(N) if (0)
unsigned N = omp_get_max_threads();
#pragma omp parallel num_threads(N + 1) if (0)
#pragma omp single
{ printf("BBB %2d\n", omp_get_num_threads()); }
#pragma omp parallel
#pragma omp single
{
if (omp_get_num_threads() != N)
if (omp_get_num_threads() <= N)
printf("PASS\n");
}
return 0;