re PR middle-end/70280 (-fcompare-debug failure (length) with…

re PR middle-end/70280 (-fcompare-debug failure (length) with --param=integer-share-limit=4016 -mavx512bw)

	PR c/70280
	* c-typeck.c (composite_type): Don't count void_list_node
	into len, if the list is terminated by void_list_node, start
	with void_list_node instead of NULL for newargs.  Stop
	at void_list_node.

From-SVN: r234312

gcc/c/ChangeLog

+2016-03-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/70280
+	* c-typeck.c (composite_type): Don't count void_list_node
+	into len, if the list is terminated by void_list_node, start
+	with void_list_node instead of NULL for newargs.  Stop
+	at void_list_node.
+
 2016-03-16  Marek Polacek  <polacek@redhat.com>
 
 	PR c/70093

gcc/c/c-typeck.c

@@ -518,15 +518,17 @@ composite_type (tree t1, tree t2)
 	/* If both args specify argument types, we must merge the two
 	   lists, argument by argument.  */
 
-	len = list_length (p1);
-	newargs = 0;
+	for (len = 0, newargs = p1;
+	     newargs && newargs != void_list_node;
+	     len++, newargs = TREE_CHAIN (newargs))
+	  ;
 
 	for (i = 0; i < len; i++)
 	  newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 
 	n = newargs;
 
-	for (; p1;
+	for (; p1 && p1 != void_list_node;
 	     p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
 	  {
 	    /* A null type means arg type is not specified.