openmp: Add support for iterators in 'target update' clauses (C/C++)

This adds support for iterators in 'to' and 'from' clauses in the
'target update' OpenMP directive.

gcc/c/

	* c-parser.cc (c_parser_omp_clause_from_to): Parse 'iterator' modifier.
	* c-typeck.cc (c_finish_omp_clauses): Finish iterators for to/from
	clauses.

gcc/cp/

	* parser.cc (cp_parser_omp_clause_from_to): Parse 'iterator' modifier.
	* semantics.cc (finish_omp_clauses): Finish iterators for to/from
	clauses.

gcc/

	* gimplify.cc (gimplify_scan_omp_clauses): Add argument for iterator
	loop sequence.   Gimplify the clause decl and size into the iterator
	loop if iterators are used.
	(gimplify_omp_workshare): Add argument for iterator loops sequence
	in call to gimplify_scan_omp_clauses.
	(gimplify_omp_target_update): Call remove_unused_omp_iterator_vars and
	build_omp_iterators_loops.  Add loop sequence as argument when calling
	gimplify_scan_omp_clauses, gimplify_adjust_omp_clauses and building
	the Gimple statement.
	* tree-pretty-print.cc (dump_omp_clause): Call dump_omp_iterators
	for to/from clauses with iterators.
	* tree.cc (omp_clause_num_ops): Add extra operand for OMP_CLAUSE_FROM
	and OMP_CLAUSE_TO.
	* tree.h (OMP_CLAUSE_HAS_ITERATORS): Add check for OMP_CLAUSE_TO and
	OMP_CLAUSE_FROM.
	(OMP_CLAUSE_ITERATORS): Likewise.

gcc/testsuite/

	* c-c++-common/gomp/target-update-iterators-1.c: New.
	* c-c++-common/gomp/target-update-iterators-2.c: New.
	* c-c++-common/gomp/target-update-iterators-3.c: New.

libgomp/

	* target.c (gomp_update): Call gomp_merge_iterator_maps.  Free
	allocated variables.
	* testsuite/libgomp.c-c++-common/target-update-iterators-1.c: New.
	* testsuite/libgomp.c-c++-common/target-update-iterators-2.c: New.
	* testsuite/libgomp.c-c++-common/target-update-iterators-3.c: New.

1 files changed, 45 insertions, 10 deletions

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 8c85cce..f1c7efc 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -20988,8 +20988,11 @@ c_parser_omp_clause_device_type (c_parser *parser, tree list)
    to ( variable-list )
 
    OpenMP 5.1:
-   from ( [present :] variable-list )
-   to ( [present :] variable-list ) */
+   from ( [motion-modifier[,] [motion-modifier[,]...]:] variable-list )
+   to ( [motion-modifier[,] [motion-modifier[,]...]:] variable-list )
+
+   motion-modifier:
+     present | iterator (iterators-definition)  */
 
 static tree
 c_parser_omp_clause_from_to (c_parser *parser, enum omp_clause_code kind,
@@ -21001,20 +21004,27 @@ c_parser_omp_clause_from_to (c_parser *parser, enum omp_clause_code kind,
     return list;
 
   int pos = 1, colon_pos = 0;
+  int iterator_length = 0;
 
   while (c_parser_peek_nth_token_raw (parser, pos)->type == CPP_NAME)
     {
-      if (c_parser_peek_nth_token_raw (parser, pos + 1)->type == CPP_COMMA)
-	pos += 2;
-      else if (c_parser_peek_nth_token_raw (parser, pos + 1)->type
-	       == CPP_OPEN_PAREN)
+      const char *identifier =
+	IDENTIFIER_POINTER (c_parser_peek_nth_token_raw (parser, pos)->value);
+      if (c_parser_peek_nth_token_raw (parser, pos + 1)->type
+	  == CPP_OPEN_PAREN)
 	{
 	  unsigned int npos = pos + 2;
 	  if (c_parser_check_balanced_raw_token_sequence (parser, &npos)
-	     && (c_parser_peek_nth_token_raw (parser, npos)->type
-		 == CPP_CLOSE_PAREN))
-	    pos = npos + 1;
+	      && (c_parser_peek_nth_token_raw (parser, npos)->type
+		  == CPP_CLOSE_PAREN))
+	    {
+	      if (strcmp (identifier, "iterator") == 0)
+		iterator_length = npos - pos + 1;
+	      pos = npos;
+	    }
 	}
+      if (c_parser_peek_nth_token_raw (parser, pos + 1)->type == CPP_COMMA)
+	pos += 2;
       else
 	pos++;
       if (c_parser_peek_nth_token_raw (parser, pos)->type == CPP_COLON)
@@ -21027,6 +21037,7 @@ c_parser_omp_clause_from_to (c_parser *parser, enum omp_clause_code kind,
   int present_modifier = false;
   int mapper_modifier = false;
   tree mapper_name = NULL_TREE;
+  tree iterators = NULL_TREE;
 
   for (int pos = 1; pos < colon_pos; ++pos)
     {
@@ -21048,6 +21059,17 @@ c_parser_omp_clause_from_to (c_parser *parser, enum omp_clause_code kind,
 	  present_modifier++;
 	  c_parser_consume_token (parser);
 	}
+      else if (strcmp ("iterator", p) == 0)
+	{
+	  if (iterators)
+	    {
+	      c_parser_error (parser, "too many %<iterator%> modifiers");
+	      parens.skip_until_found_close (parser);
+	      return list;
+	    }
+	  iterators = c_parser_omp_iterators (parser);
+	  pos += iterator_length - 1;
+	}
       else if (strcmp ("mapper", p) == 0)
 	{
 	  c_parser_consume_token (parser);
@@ -21104,7 +21126,7 @@ c_parser_omp_clause_from_to (c_parser *parser, enum omp_clause_code kind,
       else
 	{
 	  c_parser_error (parser, "%<to%> or %<from%> clause with modifier "
-			  "other than %<present%> or %<mapper%>");
+			  "other than %<iterator%>, %<mapper%> or %<present%>");
 	  parens.skip_until_found_close (parser);
 	  return list;
 	}
@@ -21141,6 +21163,19 @@ c_parser_omp_clause_from_to (c_parser *parser, enum omp_clause_code kind,
       OMP_CLAUSE_CHAIN (last_new) = name;
     }
 
+  if (iterators)
+    {
+      tree block = pop_scope ();
+      if (iterators == error_mark_node)
+	iterators = NULL_TREE;
+      else
+	TREE_VEC_ELT (iterators, 5) = block;
+    }
+
+  if (iterators)
+    for (tree c = nl; c != list; c = OMP_CLAUSE_CHAIN (c))
+      OMP_CLAUSE_ITERATORS (c) = iterators;
+
   return nl;
 }