OpenMP/Fortran: Use firstprivat not alloc for ptr attach for arrays
For a non-descriptor array, map(A(n:m)) was mapped as
map(tofrom:A[n-1] [len: ...]) map(alloc:A [pointer assign, bias: ...])
with this patch, it is changed to
map(tofrom:A[n-1] [len: ...]) map(firstprivate:A [pointer assign, bias: ...])
The latter avoids an alloc - and also avoids the race condition with
nowait in the enclosed testcase. (Note: predantically, the testcase is
invalid since OpenMP 5.1, violating the map clause restriction at [354:10-13].
gcc/fortran/ChangeLog:
* trans-openmp.cc (gfc_trans_omp_clauses): When mapping nondescriptor
array sections, use GOMP_MAP_FIRSTPRIVATE_POINTER instead of
GOMP_MAP_POINTER for the pointer attachment.
libgomp/ChangeLog:
* testsuite/libgomp.fortran/target-nowait-array-section.f90: New test.