re PR objc/80949 (ICE in do_warn_duplicated_branches_r)

	PR objc/80949
	* c-warn.c (do_warn_duplicated_branches): Return if any of the
	branches is null.

From-SVN: r249171

gcc/c-family/ChangeLog

+2017-06-13  Marek Polacek  <polacek@redhat.com>
+
+	PR objc/80949
+	* c-warn.c (do_warn_duplicated_branches): Return if any of the
+	branches is null.
+
 2017-06-13  Martin Liska  <mliska@suse.cz>
 
 	PR sanitize/78204

gcc/c-family/c-warn.c

@@ -2354,8 +2354,8 @@ do_warn_duplicated_branches (tree expr)
   tree thenb = COND_EXPR_THEN (expr);
   tree elseb = COND_EXPR_ELSE (expr);
 
-  /* Don't bother if there's no else branch.  */
-  if (elseb == NULL_TREE)
+  /* Don't bother if any of the branches is missing.  */
+  if (thenb == NULL_TREE || elseb == NULL_TREE)
     return;
 
   /* And don't warn for empty statements.  */