[PATCH, PR90030] Fortran OpenMP/OpenACC array mapping alignment fix

[Chung-Lin Tang]

Ping.

On 2021/11/4 4:23 PM, Chung-Lin Tang wrote:
> Hi Jakub,
> As Thomas reported and submitted a patch a while ago:
> https://gcc.gnu.org/pipermail/gcc-patches/2019-April/519932.html
> https://gcc.gnu.org/pipermail/gcc-patches/2019-May/522738.html
> 
> There's an issue with the Fortran front-end when mapping arrays: when
> creating the data MEM_REF for the map clause, there's a convention of
> casting the referencing pointer to 'c_char *' by
> fold_convert (build_pointer_type (char_type_node), ptr).
> 
> This causes the alignment passed to the libgomp runtime for array data
> hardwared to '1', and causes alignment errors on the offload target
> (not always showing up, but can trigger due to slight change of clause
> ordering)
> 
> This patch is not exactly Thomas' patch from 2019, but does the same
> thing. The new libgomp tests are directly reused though. A lot of
> scan test adjustment is also included in this patch.
> 
> Patch has been tested for no regressions for gfortran and libgomp, is
> this okay for trunk?
> 
> Thanks,
> Chung-Lin
> 
> Fortran: fix array alignment for OpenMP/OpenACC target mapping clauses [PR90030]
> 
> The Fortran front-end is creating maps of array data with a type of pointer to
> char_type_node, which when eventually passed to libgomp during runtime, marks
> the passed array with an alignment of 1, which can cause mapping alignment
> errors on the offload target.
> 
> This patch removes the related fold_convert(build_pointer_type (char_type_node))
> calls in fortran/trans-openmp.c, and adds gcc_asserts to ensure pointer type.
> 
> 2021-11-04  Chung-Lin Tang  <cltang@codesourcery.com>
>          Thomas Schwinge <thomas@codesourcery.com>
> 
>      PR fortran/90030
> 
> gcc/fortran/ChangeLog:
> 
>      * trans-openmp.c (gfc_omp_finish_clause): Remove fold_convert to pointer
>      to char_type_node, add gcc_assert of POINTER_TYPE_P.
>      (gfc_trans_omp_array_section): Likewise.
>      (gfc_trans_omp_clauses): Likewise.
> 
> gcc/testsuite/ChangeLog:
> 
>      * gfortran.dg/goacc/finalize-1.f: Adjust scan test.
>      * gfortran.dg/gomp/affinity-clause-1.f90: Likewise.
>      * gfortran.dg/gomp/affinity-clause-5.f90: Likewise.
>      * gfortran.dg/gomp/defaultmap-4.f90: Likewise.
>      * gfortran.dg/gomp/defaultmap-5.f90: Likewise.
>      * gfortran.dg/gomp/defaultmap-6.f90: Likewise.
>      * gfortran.dg/gomp/map-3.f90: Likewise.
>      * gfortran.dg/gomp/pr78260-2.f90: Likewise.
>      * gfortran.dg/gomp/pr78260-3.f90: Likewise.
> 
> libgomp/ChangeLog:
> 
>      * testsuite/libgomp.oacc-fortran/pr90030.f90: New test.
>      * testsuite/libgomp.fortran/pr90030.f90: New test.