diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index c78c71f2bf99..aa98bfed646f 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2010-11-02  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* include/std/bitset (_Base_bitset<>_Base_bitset(unsigned long long)):
+	Convert __val to _WordT.
+
 2010-11-01  Benjamin Kosnik  <bkoz@redhat.com>
 
 	* include/std/chrono: Extend constexpr application.
diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index fafbb32dd0c3..db20eaf07143 100644
--- a/libstdc++-v3/include/std/bitset
+++ b/libstdc++-v3/include/std/bitset
@@ -76,9 +76,9 @@ _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
       constexpr _Base_bitset() : _M_w({ }) { }
 
       constexpr _Base_bitset(unsigned long long __val)
-      : _M_w({ __val
+      : _M_w({ _WordT(__val)
 #if __SIZEOF_LONG_LONG__ > __SIZEOF_LONG__
-	       , __val >> _GLIBCXX_BITSET_BITS_PER_WORD
+	       , _WordT(__val >> _GLIBCXX_BITSET_BITS_PER_WORD)
 #endif
        }) { }
 #else