On 21.01.22 18:43, Tobias Burnus wrote:
> On 21.01.22 18:15, Thomas Schwinge wrote:
>>         11 |     integer(c_int) function is_64bit_aligned (a) bind(C)
>>      Warning: Variable ‘a’ at (1) is a dummy argument of the BIND(C)
>> procedure ‘is_64bit_aligned’ but may not be C interoperable
>> [-Wc-binding-type]
>>
>> Is that something to worry about?
I have attached a patch (not commited), which silences the three kind of
warnings and fixes the interface issue.
TODO: commit it.

On 21.01.22 18:15, Thomas Schwinge wrote:
> I'm seeing this test case randomly/non-deterministically FAIL to execute,
> differently on different systems and runs, for example: [...]
> I'd assume there's some concurrency issue: the problem disappears if I
> manually specify a lowerish 'OMP_NUM_THREADS'

If one compiles the program with -fsanitize=thread, it shows tons of errors :-(
The first one is:

WARNING: ThreadSanitizer: data race (pid=3034413)
   Read of size 8 at 0x7fff8b5a8340 by thread T1:
     #0 __m_MOD_foo._omp_fn.2 ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:116 (a.out+0x402a88)
     #1 gomp_thread_start ../../../repos/gcc-trunk-commit/libgomp/team.c:129 (libgomp.so.1+0x1e5ed)

   Previous write of size 8 at 0x7fff8b5a8340 by main thread:
     #0 __m_MOD_foo._omp_fn.1 ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:116 (a.out+0x4029c0)
     #1 GOMP_teams_reg ../../../repos/gcc-trunk-commit/libgomp/teams.c:51 (libgomp.so.1+0x3638c)
     #2 MAIN__ ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:328 (a.out+0x4024c0)
     #3 main ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:312 (a.out+0x4025b0)

   Location is stack of main thread.

   Location is global '<null>' at 0x000000000000 ([stack]+0x1f340)

   Thread T1 (tid=3034416, running) created by main thread at:
     #0 pthread_create ../../../../repos/gcc-trunk-commit/libsanitizer/tsan/tsan_interceptors_posix.cpp:1001 (libtsan.so.2+0x62c76)
     #1 gomp_team_start ../../../repos/gcc-trunk-commit/libgomp/team.c:858 (libgomp.so.1+0x1ec18)
     #2 MAIN__ ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:328 (a.out+0x4024c0)
     #3 main ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:312 (a.out+0x4025b0)

SUMMARY: ThreadSanitizer: data race ../../libgomp/testsuite/libgomp.fortran/allocate-1.f90:116 in __m_MOD_foo._omp_fn.2

Tobias
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