[Bug fortran/120505] [OpenMP] Fortran deep mapping of alloc comp + component mapping like 'map(var%arr(1)%alloc)' in target (enter/exit) data

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120505

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Paul-Antoine Arras <parras@gcc.gnu.org>:

https://gcc.gnu.org/g:99cfdcee2fe9b0f5230f17fd3226825259171138

commit r16-7646-g99cfdcee2fe9b0f5230f17fd3226825259171138
Author: Paul-Antoine Arras <parras@baylibre.com>
Date:   Fri Feb 20 14:21:29 2026 +0100

    OpenMP/Fortran: Map intermediate array descriptors [PR120505]

    Consider the following OMP directive, assuming tiles is allocatable:

    !$omp target enter data &
    !$omp   map(to: chunk%tiles(1)%field%density0) &
    !$omp   map(to: chunk%left_rcv_buffer)

    libgomp reports an illegal memory access error at runtime. This is because
    density0 is referenced through tiles, which requires its descriptor to be
mapped
    along its content.

    This patch ensures that all such intervening allocatables in a reference
chain
    are properly mapped. For the above example, the frontend has to create the
    following three additional map clauses:

    (1) map (alloc: *(struct tile_type[0:] * restrict) chunk.tiles.data [len:
0])
    (2) map (to: chunk.tiles [pointer set, len: 64])
    (3) map (attach_detach: (struct tile_type[0:] * restrict) chunk.tiles.data
    [bias: -1])

    (1) is required by the gimplifier for attaching but will be removed at the
end
    of the pass; the inner component is explicitly to-mapped elsewhere. (2)
ensures
    that the array descriptor will be available at runtime to compute offsets
and
    strides in various dimensions. The gimplifier will turn (3) into a regular
    attach of the data pointer and compute the bias.

            PR fortran/120505

    gcc/fortran/ChangeLog:

            * trans-openmp.cc (gfc_map_array_descriptor): New function.
            (gfc_trans_omp_clauses): Emit map clauses for intermediate array
            descriptors.

    gcc/ChangeLog:

            * gimplify.cc (omp_mapped_by_containing_struct): Handle Fortran
array
            descriptors.
            (omp_build_struct_sibling_lists): Allow attach_detach bias to be
            adjusted on non-target regions.
            (gimplify_adjust_omp_clauses): Remove GIMPLE-only nodes.
            * tree-pretty-print.cc (dump_omp_clause): Handle
            OMP_CLAUSE_MAP_SIZE_NEEDS_ADJUSTMENT and
OMP_CLAUSE_MAP_GIMPLE_ONLY.
            * tree.h (OMP_CLAUSE_MAP_SIZE_NEEDS_ADJUSTMENT,
            OMP_CLAUSE_MAP_GIMPLE_ONLY): Define.

    libgomp/ChangeLog:

            * testsuite/libgomp.fortran/map-subarray-11.f90: New test.
            * testsuite/libgomp.fortran/map-subarray-13.f90: New test.
            * testsuite/libgomp.fortran/map-subarray-14.f90: New test.
            * testsuite/libgomp.fortran/map-subarray-15.f90: New test.
            * testsuite/libgomp.fortran/map-subarray-16.f90: New test.
            * testsuite/libgomp.fortran/map-alloc-present-2.f90: New file.

    gcc/testsuite/ChangeLog:

            * gfortran.dg/gomp/map-subarray-3.f90: New test.
            * gfortran.dg/gomp/map-subarray-5.f90: New test.