Make runtime/test/barrier/omp_barrier.c pass on 2-core machines

[dsanders]

Summary

This test currently expects omp_get_thread_num() to return 1 and 2, effectively requiring three threads. 2-core machines only seem to spawn two threads, preventing omp_get_thread_num() from returning 2. This patch changes the expected thread numbers to 0 and 1 so that it passes on 2-core machines.

This fixes the last issue in the x86_64-linux-gnu-debian8 build of the 3.8.0 release.

[dsanders]

Please note, that I don't know OpenMP very well. I don't think this changes the nature of the test based on what little I've read of the spec but I could be mistaken.

[AndreyChurbanov]

Suggested change does not fix the test reliably, because it will still fail on a single processor machine.

I am sorry if I broken some rules here, but I have committed more reliable fix for the test (revision #258695) so that
(1) it now passes on any number of processors, and (2) it runs in 1 sec instead of in 10 sec in initial implementation.

I don't think it makes much sense to have threads to spin 10 times per 1 sec in order to check the barrier, much smaller delay is perfectly enough (I've reduced it to 10 x 0.1 sec).

Feel free to comment.
Thanks, Andrey.

[dsanders]

Thanks for the quick response. As you say, your version fixes more cases than mine does and also speeds it up.

Abandoning this review since a better fix has been committed.

runtime/test/barrier/omp_barrier.c

 // RUN: %libomp-compile-and-run
 #include <stdio.h>
 #include "omp_testsuite.h"
 #include "omp_my_sleep.h"
 
 int test_omp_barrier()
 {
   int result1;
   int result2;
   result1 = 0;
   result2 = 0;
 
   #pragma omp parallel
   {
     int rank;
     rank = omp_get_thread_num ();
-    if (rank ==1) {
+    if (rank == 0) {
       my_sleep(SLEEPTIME);
       result2 = 3;
     }
     #pragma omp barrier
-    if (rank == 2) {
+    if (rank == 1) {
       result1 = result2;
     }
   }
   return (result1 == 3);
 }
 
 int main()
 {