Add support for device-modifiers for 'omp target device'.

'device_num' and 'ancestor' are now parsed on target device constructs for C,
C++, and Fortran (see OpenMP specification 5.0, p. 170). When 'ancestor' is
 used, then 'sorry, not supported' is output. Moreover, the restrictions for
'ancestor' are implemented (see OpenMP specification 5.0, p. 174f).

gcc/c/ChangeLog:

	* c-parser.c (c_parser_omp_clause_device): Parse device-modifiers 'device_num'
	and 'ancestor' in 'target device' clauses.

gcc/cp/ChangeLog:

	* parser.c (cp_parser_omp_clause_device): Parse device-modifiers 'device_num'
	and 'ancestor' in 'target device' clauses.
	* semantics.c (finish_omp_clauses): Error handling. Constant device ids must
	evaluate to '1' if 'ancestor' is used.

gcc/fortran/ChangeLog:

	* gfortran.h: Add variable for 'ancestor' in struct gfc_omp_clauses.
	* openmp.c (gfc_match_omp_clauses): Parse device-modifiers 'device_num'
	and 'ancestor' in 'target device' clauses.
	* trans-openmp.c (gfc_trans_omp_clauses): Set OMP_CLAUSE_DEVICE_ANCESTOR.

gcc/ChangeLog:

	* gimplify.c (gimplify_scan_omp_clauses): Error handling. 'ancestor' only
	allowed on target constructs and only with particular other clauses.
	* omp-expand.c (expand_omp_target): Output of 'sorry, not supported' if
	'ancestor' is used.
	* omp-low.c (check_omp_nesting_restrictions): Error handling. No nested OpenMP
	structs when 'ancestor' is used.
	(scan_omp_1_stmt): No usage of OpenMP runtime routines in a target region when
	'ancestor' is used.
	* tree-pretty-print.c (dump_omp_clause): Append 'ancestor'.
	* tree.h (OMP_CLAUSE_DEVICE_ANCESTOR): Define macro.

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/target-device-1.c: New test.
	* c-c++-common/gomp/target-device-2.c: New test.
	* c-c++-common/gomp/target-device-ancestor-1.c: New test.
	* c-c++-common/gomp/target-device-ancestor-2.c: New test.
	* c-c++-common/gomp/target-device-ancestor-3.c: New test.
	* c-c++-common/gomp/target-device-ancestor-4.c: New test.
	* gfortran.dg/gomp/target-device-1.f90: New test.
	* gfortran.dg/gomp/target-device-2.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-1.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-2.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-3.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-4.f90: New test.

1 files changed, 67 insertions, 17 deletions

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 356cf25..3b1d10f 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -15945,37 +15945,87 @@ c_parser_omp_clause_map (c_parser *parser, tree list)
 }
 
 /* OpenMP 4.0:
-   device ( expression ) */
+   device ( expression )
+
+   OpenMP 5.0:
+   device ( [device-modifier :] integer-expression )
+
+   device-modifier:
+     ancestor | device_num */
 
 static tree
 c_parser_omp_clause_device (c_parser *parser, tree list)
 {
   location_t clause_loc = c_parser_peek_token (parser)->location;
-  matching_parens parens;
-  if (parens.require_open (parser))
-    {
-      location_t expr_loc = c_parser_peek_token (parser)->location;
-      c_expr expr = c_parser_expr_no_commas (parser, NULL);
-      expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
-      tree c, t = expr.value;
-      t = c_fully_fold (t, false, NULL);
+  location_t expr_loc;
+  c_expr expr;
+  tree c, t;
+  bool ancestor = false;
 
-      parens.skip_until_found_close (parser);
+  matching_parens parens;
+  if (!parens.require_open (parser))
+    return list;
 
-      if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
+  if (c_parser_next_token_is (parser, CPP_NAME)
+      && c_parser_peek_2nd_token (parser)->type == CPP_COLON)
+    {
+      c_token *tok = c_parser_peek_token (parser);
+      const char *p = IDENTIFIER_POINTER (tok->value);
+      if (strcmp ("ancestor", p) == 0)
 	{
-	  c_parser_error (parser, "expected integer expression");
+	  /* A requires directive with the reverse_offload clause must be
+	  specified.  */
+	  if ((omp_requires_mask & OMP_REQUIRES_REVERSE_OFFLOAD) == 0)
+	    {
+	      error_at (tok->location, "%<ancestor%> device modifier not "
+				       "preceded by %<requires%> directive "
+				       "with %<reverse_offload%> clause");
+	      parens.skip_until_found_close (parser);
+	      return list;
+	    }
+	  ancestor = true;
+	}
+      else if (strcmp ("device_num", p) == 0)
+	;
+      else
+	{
+	  error_at (tok->location, "expected %<ancestor%> or %<device_num%>");
+	  parens.skip_until_found_close (parser);
 	  return list;
 	}
+      c_parser_consume_token (parser);
+      c_parser_consume_token (parser);
+    }
 
-      check_no_duplicate_clause (list, OMP_CLAUSE_DEVICE, "device");
+  expr_loc = c_parser_peek_token (parser)->location;
+  expr = c_parser_expr_no_commas (parser, NULL);
+  expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
+  t = expr.value;
+  t = c_fully_fold (t, false, NULL);
 
-      c = build_omp_clause (clause_loc, OMP_CLAUSE_DEVICE);
-      OMP_CLAUSE_DEVICE_ID (c) = t;
-      OMP_CLAUSE_CHAIN (c) = list;
-      list = c;
+  parens.skip_until_found_close (parser);
+
+  if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
+    {
+      c_parser_error (parser, "expected integer expression");
+      return list;
     }
+  if (ancestor && TREE_CODE (t) == INTEGER_CST && !integer_onep (t))
+    {
+      error_at (expr_loc, "the %<device%> clause expression must evaluate to "
+			  "%<1%>");
+      return list;
+    }
+
+  check_no_duplicate_clause (list, OMP_CLAUSE_DEVICE, "device");
+
+  c = build_omp_clause (clause_loc, OMP_CLAUSE_DEVICE);
 
+  OMP_CLAUSE_DEVICE_ID (c) = t;
+  OMP_CLAUSE_CHAIN (c) = list;
+  OMP_CLAUSE_DEVICE_ANCESTOR (c) = ancestor;
+
+  list = c;
   return list;
 }