[Bug fortran/92929] New: Fortran OpenACC/OpenMP 'target' 'exit data'/'update' optimizations

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92929

            Bug ID: 92929
           Summary: Fortran OpenACC/OpenMP 'target' 'exit data'/'update'
                    optimizations
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: openacc, openmp
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: burnus at gcc dot gnu.org, jakub at gcc dot gnu.org,
                    jules at gcc dot gnu.org
  Target Milestone: ---

As of Tobias' recent r277631 "Fortran/OpenMP] Don't create "alloc:" for 'target
exit data'",
<http://mid.mail-archive.com/7a5f39e8-a33b-048a-f9c1-1355b941771e@codesourcery.com>,
this is done for Fortran OpenMP '!$omp target exit data'/'!$omp target update',
but not for OpenACC '!$acc exit data'/'!$acc update'; see
'gcc/gimplify.c:gimplify_scan_omp_clauses':

    /* For Fortran, not only the pointer to the data is mapped but also
       the address of the pointer, the array descriptor etc.; for
       'exit data' - and in particular for 'delete:' - having an 'alloc:'
       does not make sense.  Likewise, for 'update' only transferring the
       data itself is needed as the rest has been handled in previous
       directives.  */
    if ((code == OMP_TARGET_EXIT_DATA || code == OMP_TARGET_UPDATE)
        && (OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_POINTER
            || OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_TO_PSET))
      remove = true;

Note that I'm not proposing to also do that for OpenACC at this point; I have
one doubt about that I need to look into first, but don't have time for right
now.