diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 7a5b7f76864..7deae75a391 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,12 @@
+2010-12-06  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR libstdc++/46821
+	* include/std/tuple (_Head_base<,, true>::_M_swap_impl):
+	Swap the empty bases.
+	(_Head_base<,, false>::_M_swap_impl): Minor tweak.
+	* testsuite/20_util/weak_ptr/comparison/cmp_neg.cc: Adjust dg-error
+	line number.
+
 2010-12-06  Dave Korn  <dave.korn.cygwin@gmail.com>
 
 	PR target/40125
@@ -54,7 +63,7 @@
 	* testsuite/23_containers/deque/cons/2.cc: Fix to explicitly invoke
 	the copy constructor with or without C++0x mode.
 	* testsuite/23_containers/vector/cons/4.cc: Likewise.
-			
+
 2010-12-01  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* scripts/extract_symvers.pl: New file.
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index df9ef1d1694..87dbcb78df6 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -78,7 +78,11 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
       const _Head& _M_head() const { return *this; }
     
       void 
-      _M_swap_impl(_Head&) { /* no-op */ }
+      _M_swap_impl(_Head& __h)
+      {
+	using std::swap;
+	swap(__h, _M_head());
+      }
     };
 
   template<std::size_t _Idx, typename _Head>
@@ -101,7 +105,7 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
       _M_swap_impl(_Head& __h)
       { 
 	using std::swap;
-	swap(__h, _M_head_impl);
+	swap(__h, _M_head());
       }
 
       _Head _M_head_impl; 
diff --git a/libstdc++-v3/testsuite/20_util/weak_ptr/comparison/cmp_neg.cc b/libstdc++-v3/testsuite/20_util/weak_ptr/comparison/cmp_neg.cc
index 7f5b109b61e..044a7259e18 100644
--- a/libstdc++-v3/testsuite/20_util/weak_ptr/comparison/cmp_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/weak_ptr/comparison/cmp_neg.cc
@@ -44,7 +44,7 @@ main()
 // { dg-warning "note" "" { target *-*-* } 350 }
 // { dg-warning "note" "" { target *-*-* } 1082 }
 // { dg-warning "note" "" { target *-*-* } 465 }
-// { dg-warning "note" "" { target *-*-* } 581 }
+// { dg-warning "note" "" { target *-*-* } 585 }
 // { dg-warning "note" "" { target *-*-* } 1027 }
 // { dg-warning "note" "" { target *-*-* } 340 }
 // { dg-warning "note" "" { target *-*-* } 290 }