[expand] Handle null target in expand_builtin_goacc_parlevel_id_size

2018-05-04  Tom de Vries  <tom@codesourcery.com>

	PR libgomp/85639
	* builtins.c (expand_builtin_goacc_parlevel_id_size): Handle null target
	if ignore == 0.

From-SVN: r259927

gcc/ChangeLog

+2018-05-04  Tom de Vries  <tom@codesourcery.com>
+
+	PR libgomp/85639
+	* builtins.c (expand_builtin_goacc_parlevel_id_size): Handle null target
+	if ignore == 0.
+
 2018-05-04  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/85627

gcc/builtins.c

@@ -6682,6 +6682,9 @@ expand_builtin_goacc_parlevel_id_size (tree exp, rtx target, int ignore)
   if (ignore)
     return target;
 
+  if (target == NULL_RTX)
+    target = gen_reg_rtx (TYPE_MODE (TREE_TYPE (exp)));
+
   if (!targetm.have_oacc_dim_size ())
     {
       emit_move_insn (target, fallback_retval);