Re: [Patch] OpenMP: Accept argument to depobj's destroy clause

[Jakub Jelinek <jakub@redhat.com>]

On Thu, Nov 23, 2023 at 04:21:50PM +0100, Tobias Burnus wrote:
> @@ -21663,7 +21666,25 @@ c_parser_omp_depobj (c_parser *parser)
>  	    clause = error_mark_node;
>  	}
>        else if (!strcmp ("destroy", p))
> -	kind = OMP_CLAUSE_DEPEND_LAST;
> +	{
> +	  matching_parens c_parens;
> +	  kind = OMP_CLAUSE_DEPEND_LAST;
> +	  if (c_parser_next_token_is (parser, CPP_OPEN_PAREN)
> +	      && c_parens.require_open (parser))
> +	    {
> +	      tree destobj = c_parser_expr_no_commas (parser, NULL).value;
> +	      if (!lvalue_p (destobj))
> +		error_at (EXPR_LOC_OR_LOC (destobj, c_loc),
> +			  "%<destrory%> expression is not lvalue expression");
> +	      else if (depobj != error_mark_node
> +		       && !operand_equal_p (destobj, depobj,
> +					    OEP_MATCH_SIDE_EFFECTS))

There is also OEP_LEXICOGRAPHIC which could be used in addition to that.
The question is if we want to consider say
#pragma depobj (a[++i]) destroy (a[++i])
as same or different (similarly a[foo ()] in both cases).
A function could at least in theory return the same value, for other
side-effects there is some wiggle room in unspecified number of times how
many the side-effects of clauses are evaluated (and for destroy we really
don't intend to evaluate them at all for the clause, just for the directive
argument).

	Jakub