Re: [PATCH V2 1/5] OpenMP: Add OMP_STRUCTURED_BLOCK and GIMPLE_OMP_STRUCTURED_BLOCK.

[Jakub Jelinek <jakub@redhat.com>]

On Sun, Jul 23, 2023 at 04:15:17PM -0600, Sandra Loosemore wrote:
> In order to detect invalid jumps in and out of intervening code in
> imperfectly-nested loops, the front ends need to insert some sort of
> marker to identify the structured block sequences that they push into
> the inner body of the loop.  The error checking happens in the
> diagnose_omp_blocks pass, between gimplification and OMP lowering, so
> we need both GENERIC and GIMPLE representations of these markers.
> They are removed in OMP lowering so no subsequent passes need to know
> about them.
> 
> This patch doesn't include any front-end changes to generate the new
> data structures.
> 
> gcc/cp/ChangeLog
> 	* constexpr.cc (cxx_eval_constant_expression): Handle
> 	OMP_STRUCTURED_BLOCK.
> 	* pt.cc (tsubst_expr): Likewise.
> 
> gcc/ChangeLog
> 	* doc/generic.texi (OpenMP): Document OMP_STRUCTURED_BLOCK.
> 	* doc/gimple.texi (GIMPLE instruction set): Add
> 	GIMPLE_OMP_STRUCTURED_BLOCK.
> 	(GIMPLE_OMP_STRUCTURED_BLOCK): New subsection.
> 	* gimple-low.cc (lower_stmt): Error on GIMPLE_OMP_STRUCTURED_BLOCK.
> 	* gimple-pretty-print.cc (dump_gimple_omp_block): Handle
> 	GIMPLE_OMP_STRUCTURED_BLOCK.
> 	(pp_gimple_stmt_1): Likewise.
> 	* gimple-walk.cc (walk_gimple_stmt): Likewise.
> 	* gimple.cc (gimple_build_omp_structured_block): New.
> 	* gimple.def (GIMPLE_OMP_STRUCTURED_BLOCK): New.
> 	* gimple.h (gimple_build_omp_structured_block): Declare.
> 	(gimple_has_substatements): Handle GIMPLE_OMP_STRUCTURED_BLOCK.
> 	(CASE_GIMPLE_OMP): Likewise.
> 	* gimplify.cc (is_gimple_stmt): Handle OMP_STRUCTURED_BLOCK.
> 	(gimplify_expr): Likewise.
> 	* omp-expand.cc (GIMPLE_OMP_STRUCTURED_BLOCK): Error on
> 	GIMPLE_OMP_STRUCTURED_BLOCK.
> 	* omp-low.cc (scan_omp_1_stmt): Handle GIMPLE_OMP_STRUCTURED_BLOCK.
> 	(lower_omp_1): Likewise.
> 	(diagnose_sb_1): Likewise.
> 	(diagnose_sb_2): Likewise.
> 	* tree-inline.cc (remap_gimple_stmt): Handle
> 	GIMPLE_OMP_STRUCTURED_BLOCK.
> 	(estimate_num_insns): Likewise.
> 	* tree-nested.cc (convert_nonlocal_reference_stmt): Likewise.
> 	(convert_local_reference_stmt): Likewise.
> 	(convert_gimple_call): Likewise.
> 	* tree-pretty-print.cc (dump_generic_node): Handle
> 	OMP_STRUCTURED_BLOCK.
> 	* tree.def (OMP_STRUCTURED_BLOCK): New.
> 	* tree.h (OMP_STRUCTURED_BLOCK_BODY): New.
> --- a/gcc/gimple-low.cc
> +++ b/gcc/gimple-low.cc
> @@ -717,6 +717,11 @@ lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data)
>  	gsi_next (gsi);
>        return;
>  
> +    case GIMPLE_OMP_STRUCTURED_BLOCK:
> +      /* These are supposed to be removed already in OMP lowering.  */
> +      gcc_unreachable ();
> +      break;

Please don't add break; after gcc_unreachable ();

> --- a/gcc/omp-expand.cc
> +++ b/gcc/omp-expand.cc
> @@ -10592,6 +10592,11 @@ expand_omp (struct omp_region *region)
>  	     parent GIMPLE_OMP_SECTIONS region.  */
>  	  break;
>  
> +	case GIMPLE_OMP_STRUCTURED_BLOCK:
> +	  /* We should have gotten rid of these in gimple lowering.  */
> +	  gcc_unreachable ();
> +	  break;

And here neither.

Otherwise LGTM.

	Jakub