Index: boost/pending/lowest_bit.hpp
===================================================================
--- boost/pending/lowest_bit.hpp	(revision 68634)
+++ boost/pending/lowest_bit.hpp	(working copy)
@@ -32,7 +32,26 @@
 
     }
 
+    template<>
+    inline int lowest_bit(unsigned int x) {
+        assert(x >= 1); // PRE
 
+        return __builtin_ctz( x );
+    }
+
+    template<>
+    inline int lowest_bit(unsigned long x) {
+        assert(x >= 1); // PRE
+
+        return __builtin_ctzl( x );
+    }
+
+    template<>
+    inline int lowest_bit(unsigned long long x) {
+        assert(x >= 1); // PRE
+
+        return __builtin_ctzll( x );
+    }
 }