Re: [PATCH, stage 1] Fortran: Add support for OMP non-rectangular loops

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Mar 25, 2022 at 08:03:38PM -0600, Sandra Loosemore wrote:
>     This patch adds support for OMP 5.1 "canonical loop nest form" to the
>     Fortran front end, marks non-rectangular loops for processing
>     by the middle end, and implements missing checks in the gimplifier
>     for additional prohibitions on non-rectangular loops.
>     
>     Note that the OMP spec also prohibits non-rectangular loops with the TILE
>     construct; that construct hasn't been implemented yet, so that error will
>     need to be filled in later.
>     
>     	gcc/fortran/
>     	* gfortran.h (struct gfc_omp_clauses): Add non_rectangular bit.
>     	* openmp.cc (is_outer_iteration_variable): New function.
>     	(expr_is_invariant): New function.
>     	(bound_expr_is_canonical): New function.
>     	(resolve_omp_do): Replace existing non-rectangularity error with
>     	check for canonical form and setting non_rectangular bit.
>     	* trans-openmp.cc (gfc_trans_omp_do): Transfer non_rectangular
>     	flag to generated tree structure.
>     
>     	gcc/
>     	* gimplify.cc (gimplify_omp_for): Update messages for SCHEDULED
>     	and ORDERED clause conflict errors.  Add check for GRAINSIZE and
>     	NUM_TASKS on TASKLOOP.
>     
>     	gcc/testsuite/
>     	* c-c++-common/gomp/loop-6.c (f3): New function to test TASKLOOP
>     	diagnostics.
>     	* gfortran.dg/gomp/collapse1.f90: Update expected messages.
>     	* gfortran.dg/gomp/pr85313.f90: Remove dg-error on non-rectangular
>     	loops that are now accepted.
>     	* gfortran.dg/gomp/non-rectangular-loop.f90: New file.
>     	* gfortran.dg/gomp/canonical-loop-1.f90: New file.
>     	* gfortran.dg/gomp/canonical-loop-2.f90: New file.
> 
> --- a/gcc/gimplify.cc
> +++ b/gcc/gimplify.cc
> @@ -12468,11 +12468,11 @@ gimplify_omp_for (tree *expr_p, gimple_seq *pre_p)
>  			       OMP_CLAUSE_SCHEDULE))
>  	    error_at (EXPR_LOCATION (for_stmt),
>  		      "%qs clause may not appear on non-rectangular %qs",
> -		      "schedule", "for");
> +		      "schedule", (lang_GNU_Fortran () ? "do" : "for"));
>  	  if (omp_find_clause (OMP_FOR_CLAUSES (for_stmt), OMP_CLAUSE_ORDERED))
>  	    error_at (EXPR_LOCATION (for_stmt),
>  		      "%qs clause may not appear on non-rectangular %qs",
> -		      "ordered", "for");
> +		      "ordered", (lang_GNU_Fortran () ? "do" : "for"));

Please drop the superfluous ()s around the argument, just use
		      "...", lang_GNU_Fortran () ? "do" : "for");

Ok for trunk with that nit fixed.  And thanks for discovering the missing
grainsize/num_tasks checks.

	Jakub