diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 5440e10..462e35f 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1763,11 +1763,10 @@ bot_manip (tree* tp, int* walk_subtrees, void* data)
   splay_tree target_remap = ((splay_tree) data);
   tree t = *tp;
 
-  if (!TYPE_P (t) && TREE_CONSTANT (t))
+  if (!TYPE_P (t) && TREE_CONSTANT (t) && !TREE_SIDE_EFFECTS (t))
     {
       /* There can't be any TARGET_EXPRs or their slot variables below
-	 this point.  We used to check !TREE_SIDE_EFFECTS, but then we
-	 failed to copy an ADDR_EXPR of the slot VAR_DECL.  */
+	 this point.  */
       *walk_subtrees = 0;
       return NULL_TREE;
     }
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-defarg.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-defarg.C
new file mode 100644
index 0000000..1413b24
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-defarg.C
@@ -0,0 +1,12 @@
+// PR c++/46335
+// { dg-options -std=c++0x }
+
+struct T { };
+struct A {
+    A(const T &tr =T()) {}
+};
+struct B {
+    A k;
+};
+B kk_;
+A fk_;