diff --git a/include/boost/function/function_base.hpp b/include/boost/function/function_base.hpp
index 35afa16..2cc6bf6 100644
--- a/include/boost/function/function_base.hpp
+++ b/include/boost/function/function_base.hpp
@@ -18,6 +18,9 @@
 #include <typeinfo>
 #include <boost/config.hpp>
 #include <boost/assert.hpp>
+#include <boost/integer.hpp>
+#include <boost/type_traits/has_trivial_copy.hpp>
+#include <boost/type_traits/has_trivial_destructor.hpp>
 #include <boost/type_traits/is_const.hpp>
 #include <boost/type_traits/is_integral.hpp>
 #include <boost/type_traits/is_volatile.hpp>
@@ -625,7 +628,7 @@ public:
     if (!vtable) return typeid(void);
 
     detail::function::function_buffer type;
-    vtable->manager(functor, type, detail::function::get_functor_type_tag);
+    get_vtable()->manager(functor, type, detail::function::get_functor_type_tag);
     return *type.type.type;
   }
 
@@ -638,7 +641,7 @@ public:
       type_result.type.type = &typeid(Functor);
       type_result.type.const_qualified = is_const<Functor>::value;
       type_result.type.volatile_qualified = is_volatile<Functor>::value;
-      vtable->manager(functor, type_result, 
+      get_vtable()->manager(functor, type_result, 
                       detail::function::check_functor_type_tag);
       return static_cast<Functor*>(type_result.obj_ptr);
     }
@@ -656,7 +659,7 @@ public:
       type_result.type.type = &typeid(Functor);
       type_result.type.const_qualified = true;
       type_result.type.volatile_qualified = is_volatile<Functor>::value;
-      vtable->manager(functor, type_result, 
+      get_vtable()->manager(functor, type_result, 
                       detail::function::check_functor_type_tag);
       // GCC 2.95.3 gets the CV qualifiers wrong here, so we
       // can't do the static_cast that we should do.
@@ -702,6 +705,15 @@ public:
 #endif
 
 public: // should be protected, but GCC 2.95.3 will fail to allow access
+  detail::function::vtable_base* get_vtable() const {
+    return reinterpret_cast<detail::function::vtable_base*>(
+             reinterpret_cast<std::size_t>(vtable) & ~(std::size_t)0x01);
+  }
+
+  bool has_trivial_copy_and_destroy() const {
+    return reinterpret_cast<std::size_t>(vtable) & 0x01;
+  }
+
   detail::function::vtable_base* vtable;
   mutable detail::function::function_buffer functor;
 };
diff --git a/include/boost/function/function_template.hpp b/include/boost/function/function_template.hpp
index 584abe9..23687b4 100644
--- a/include/boost/function/function_template.hpp
+++ b/include/boost/function/function_template.hpp
@@ -678,6 +678,11 @@ namespace boost {
               R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>
       vtable_type;
 
+    vtable_type* get_vtable() const {
+      return reinterpret_cast<vtable_type*>(
+               reinterpret_cast<std::size_t>(vtable) & ~(std::size_t)0x01);
+    }
+
     struct clear_type {};
 
   public:
@@ -757,7 +762,7 @@ namespace boost {
       if (this->empty())
         boost::throw_exception(bad_function_call());
 
-      return static_cast<vtable_type*>(vtable)->invoker
+      return get_vtable()->invoker
                (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
     }
 #else
@@ -847,7 +852,8 @@ namespace boost {
     void clear()
     {
       if (vtable) {
-        reinterpret_cast<vtable_type*>(vtable)->clear(this->functor);
+        if (!this->has_trivial_copy_and_destroy())
+          get_vtable()->clear(this->functor);
         vtable = 0;
       }
     }
@@ -876,8 +882,11 @@ namespace boost {
     {
       if (!f.empty()) {
         this->vtable = f.vtable;
-        f.vtable->manager(f.functor, this->functor,
-                          boost::detail::function::clone_functor_tag);
+        if (this->has_trivial_copy_and_destroy())
+          this->functor = f.functor;
+        else
+          get_vtable()->base.manager(f.functor, this->functor,
+                                     boost::detail::function::clone_functor_tag);
       }
     }
 
@@ -903,8 +912,15 @@ namespace boost {
       static vtable_type stored_vtable = 
         { { &manager_type::manage }, &invoker_type::invoke };
 
-      if (stored_vtable.assign_to(f, functor)) vtable = &stored_vtable.base;
-      else vtable = 0;
+      if (stored_vtable.assign_to(f, functor)) {
+        std::size_t value = reinterpret_cast<std::size_t>(&stored_vtable.base);
+        if (boost::has_trivial_copy_constructor<Functor>::value &&
+            boost::has_trivial_destructor<Functor>::value &&
+            detail::function::function_allows_small_object_optimization<Functor>::value)
+          value |= (std::size_t)0x01;
+        vtable = reinterpret_cast<detail::function::vtable_base *>(value);
+      } else 
+        vtable = 0;
     }
 
     template<typename Functor,typename Allocator>
@@ -930,8 +946,15 @@ namespace boost {
       static vtable_type stored_vtable =
         { { &manager_type::manage }, &invoker_type::invoke };
 
-      if (stored_vtable.assign_to_a(f, functor, a)) vtable = &stored_vtable.base;
-      else vtable = 0;
+      if (stored_vtable.assign_to_a(f, functor, a)) { 
+        std::size_t value = reinterpret_cast<std::size_t>(&stored_vtable.base);
+        if (boost::has_trivial_copy_constructor<Functor>::value &&
+            boost::has_trivial_destructor<Functor>::value &&
+            detail::function::function_allows_small_object_optimization<Functor>::value)
+          value |= (std::size_t)0x01;
+        vtable = reinterpret_cast<detail::function::vtable_base *>(value);
+      } else 
+        vtable = 0;
     }
 
     // Moves the value from the specified argument to *this. If the argument 
@@ -947,9 +970,12 @@ namespace boost {
 #endif
         if (!f.empty()) {
           this->vtable = f.vtable;
-          f.vtable->manager(f.functor, this->functor,
-                            boost::detail::function::move_functor_tag);
-		  f.vtable = 0;
+          if (this->has_trivial_copy_and_destroy())
+            this->functor = f.functor;
+          else
+            get_vtable()->base.manager(f.functor, this->functor,
+                                     boost::detail::function::move_functor_tag);
+          f.vtable = 0;
 #if !defined(BOOST_NO_EXCEPTIONS)      
         } else {
           clear();
@@ -979,13 +1005,14 @@ namespace boost {
   template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS>
   typename BOOST_FUNCTION_FUNCTION<
       R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>::result_type
-   BOOST_FUNCTION_FUNCTION<R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>
+  inline 
+  BOOST_FUNCTION_FUNCTION<R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>
   ::operator()(BOOST_FUNCTION_PARMS) const
   {
     if (this->empty())
       boost::throw_exception(bad_function_call());
 
-    return reinterpret_cast<const vtable_type*>(vtable)->invoker
+    return get_vtable()->invoker
              (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
   }
 #endif