re PR c++/44682 (warning: variable ‘x’ set but not used)

	PR c++/44682
	* class.c (build_base_path): If want_pointer, call mark_rvalue_use
	on expr.

	* g++.dg/warn/Wunused-var-14.C: New test.

From-SVN: r161511

gcc/cp/ChangeLog

+2010-06-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/44682
+	* class.c (build_base_path): If want_pointer, call mark_rvalue_use
+	on expr.
+
 2010-06-28  Steven Bosscher  <steven@gcc.gnu.org>
 
 	* init.c: Do not include except.h.

gcc/cp/class.c

@@ -283,6 +283,8 @@ build_base_path (enum tree_code code,
   if (!want_pointer)
     /* This must happen before the call to save_expr.  */
     expr = cp_build_unary_op (ADDR_EXPR, expr, 0, tf_warning_or_error);
+  else
+    mark_rvalue_use (expr);
 
   offset = BINFO_OFFSET (binfo);
   fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);

gcc/testsuite/ChangeLog

+2010-06-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/44682
+	* g++.dg/warn/Wunused-var-14.C: New test.
+
 2010-06-28  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/43298

gcc/testsuite/g++.dg/warn/Wunused-var-14.C

+// PR c++/44682
+// { dg-do compile }
+// { dg-options "-Wunused" }
+
+struct S { virtual ~S () {} };
+struct T { virtual ~T () {} };
+struct U : S, T {};
+
+void f (U &);
+
+void
+g (void *v)
+{
+  T *t = static_cast <T *> (v);
+  U *u = static_cast <U *> (t);
+  f (*u);
+}