diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index da33a22e5f1..19d2d49b041 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,12 @@
+2005-11-10  Paolo Carlini  <pcarlini@suse.de>
+	    Peter Dimov  <pdimov@mmltd.net>
+
+	* include/tr1/boost_shared_ptr.h (_Sp_counted_base::release):
+	Optimize by manually inlining weak_release.
+
+	* include/tr1/boost_shared_ptr.h (_Sp_counted_base::release,
+	weak_release): Use explicit memory barriers.
+
 2005-11-09  Benjamin Kosnik  <bkoz@redhat.com>
 	    Paolo Carlini  <pcarlini@suse.de>
             Gabriel Dos Reis  <gdr@integrable-solutions.net>
diff --git a/libstdc++-v3/include/tr1/boost_shared_ptr.h b/libstdc++-v3/include/tr1/boost_shared_ptr.h
index 345e17f8785..3eb94fd980b 100644
--- a/libstdc++-v3/include/tr1/boost_shared_ptr.h
+++ b/libstdc++-v3/include/tr1/boost_shared_ptr.h
@@ -151,9 +151,12 @@ public:
     if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) == 1)
       {
 	dispose();
-	__glibcxx_mutex_lock(_M_mutex);
-	__glibcxx_mutex_unlock(_M_mutex);
-	weak_release();
+	
+	_GLIBCXX_READ_MEM_BARRIER;
+	_GLIBCXX_WRITE_MEM_BARRIER;
+	
+	if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) == 1)
+	  destroy();
       }
   }
 
@@ -168,8 +171,8 @@ public:
   {
     if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) == 1)
       {
-	__glibcxx_mutex_lock(_M_mutex);
-	__glibcxx_mutex_unlock(_M_mutex);
+	_GLIBCXX_READ_MEM_BARRIER;
+	_GLIBCXX_WRITE_MEM_BARRIER;
 	destroy();
       }
   }
@@ -328,7 +331,7 @@ class weak_count
 {
 private:
 
-  _Sp_counted_base * _M_pi;
+  _Sp_counted_base* _M_pi;
 
   friend class shared_count;
 
@@ -677,8 +680,8 @@ template<typename _Tp>
       _M_less(const shared_ptr<_Tp1>& __rhs) const
       { return _M_refcount < __rhs._M_refcount; }
 
-    template <typename _Tp1> friend class shared_ptr;
-    template <typename _Tp1> friend class weak_ptr;
+    template<typename _Tp1> friend class shared_ptr;
+    template<typename _Tp1> friend class weak_ptr;
 
     // friends injected into enclosing namespace and found by ADL:
     template<typename _Tp1>