On Sun, Jul 23, 2023 at 04:15:21PM -0600, Sandra Loosemore wrote:
> OpenMP 5.0 removed the restriction that multiple collapsed loops must
> be perfectly nested, allowing "intervening code" (including nested
> BLOCKs) before or after each nested loop. In GCC this code is moved
> into the inner loop body by the respective front ends.
>
> In the Fortran front end, most of the semantic processing happens during
> the translation phase, so the parse phase just collects the intervening
> statements, checks them for errors, and splices them around the loop body.
>
> gcc/fortran/ChangeLog
> * gfortran.h (struct gfc_namespace): Add omp_structured_block bit.
> * openmp.cc: Include omp-api.h.
> (resolve_omp_clauses): Consolidate inscan reduction clause conflict
> checking here.
> (find_nested_loop_in_chain): New.
> (find_nested_loop_in_block): New.
> (gfc_resolve_omp_do_blocks): Set omp_current_do_collapse properly.
> Handle imperfectly-nested loops when looking for nested omp scan.
> Refactor to move inscan reduction clause conflict checking to
> resolve_omp_clauses.
> (gfc_resolve_do_iterator): Handle imperfectly-nested loops.
> (struct icode_error_state): New.
> (icode_code_error_callback): New.
> (icode_expr_error_callback): New.
> (diagnose_intervening_code_errors_1): New.
> (diagnose_intervening_code_errors): New.
> (make_structured_block): New.
> (restructure_intervening_code): New.
> (is_outer_iteration_variable): Do not assume loops are perfectly
> nested.
> (check_nested_loop_in_chain): New.
> (check_nested_loop_in_block_state): New.
> (check_nested_loop_in_block_symbol): New.
> (check_nested_loop_in_block): New.
> (expr_uses_intervening_var): New.
> (is_intervening_var): New.
> (expr_is_invariant): Do not assume loops are perfectly nested.
> (resolve_omp_do): Handle imperfectly-nested loops.
> * trans-stmt.cc (gfc_trans_block_construct): Generate
> OMP_STRUCTURED_BLOCK if magic bit is set on block namespace.
>
> gcc/testsuite/ChangeLog
> * gfortran.dg/gomp/collapse1.f90: Adjust expected errors.
> * gfortran.dg/gomp/collapse2.f90: Likewise.
> * gfortran.dg/gomp/imperfect-gotos.f90: New.
> * gfortran.dg/gomp/imperfect-invalid-scope.f90: New.
> * gfortran.dg/gomp/imperfect1.f90: New.
> * gfortran.dg/gomp/imperfect2.f90: New.
> * gfortran.dg/gomp/imperfect3.f90: New.
> * gfortran.dg/gomp/imperfect4.f90: New.
> * gfortran.dg/gomp/imperfect5.f90: New.
>
> libgomp/ChangeLog
> * testsuite/libgomp.fortran/imperfect-destructor.f90: New.
> * testsuite/libgomp.fortran/imperfect1.f90: New.
> * testsuite/libgomp.fortran/imperfect2.f90: New.
> * testsuite/libgomp.fortran/imperfect3.f90: New.
> * testsuite/libgomp.fortran/imperfect4.f90: New.
> * testsuite/libgomp.fortran/target-imperfect1.f90: New.
> * testsuite/libgomp.fortran/target-imperfect2.f90: New.
> * testsuite/libgomp.fortran/target-imperfect3.f90: New.
> * testsuite/libgomp.fortran/target-imperfect4.f90: New.
LGTM, but please let Tobias have a second look unless he has done so
already.
Jakub
