Bail out rather than crashing in array_type_nelts if TYPE_MAX_VALUE is null.

From-SVN: r172227

gcc/ChangeLog

+2011-04-09  Duncan Sands  <baldrick@free.fr>
+
+	* tree.c (array_type_nelts): Bail out if TYPE_MAX_VALUE not set.
+
 2011-04-08  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* combine.c (combine_validate_cost): Adjust comments.  Set registered

gcc/tree.c

@@ -2462,6 +2462,10 @@ array_type_nelts (const_tree type)
   min = TYPE_MIN_VALUE (index_type);
   max = TYPE_MAX_VALUE (index_type);
 
+  /* TYPE_MAX_VALUE may not be set if the array has unknown length.  */
+  if (!max)
+    return error_mark_node;
+
   return (integer_zerop (min)
 	  ? max
 	  : fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, min));