Index: tree-flow-inline.h
===================================================================
--- tree-flow-inline.h	(revision 110761)
+++ tree-flow-inline.h	(working copy)
@@ -1463,6 +1463,11 @@ get_subvar_at (tree var, unsigned HOST_W
 static inline bool
 var_can_have_subvars (tree v)
 {
+
+  /* Volatile variables should never have subvars.  */
+  if (TREE_THIS_VOLATILE (v))
+    return false;
+
   /* Non decls or memory tags can never have subvars.  */
   if (!DECL_P (v) || MTAG_P (v))
     return false;