diff --git a/libstdc++-v3/include/bits/allocator.h b/libstdc++-v3/include/bits/allocator.h
index 2081386..9e8afed 100644
--- a/libstdc++-v3/include/bits/allocator.h
+++ b/libstdc++-v3/include/bits/allocator.h
@@ -241,6 +241,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 #endif
 
+  template<typename _Alloc, bool
+	   = !__is_empty(_Alloc) && __is_trivial(_Alloc)>
+    struct __alloc_value_initializer;
+
+  template<typename _Alloc>
+    struct __alloc_value_initializer<_Alloc, true> : public _Alloc
+    {
+      // Explicit value initialization.
+      __alloc_value_initializer() _GLIBCXX_USE_NOEXCEPT
+	: _Alloc()
+      { }
+
+      __alloc_value_initializer(const _Alloc& __other)
+	_GLIBCXX_NOEXCEPT_IF( noexcept(_Alloc(__other)) )
+	: _Alloc(__other)
+      { }
+
+#if __cplusplus >= 201103L
+      __alloc_value_initializer(_Alloc&& __other)
+	noexcept( noexcept(_Alloc(std::move(__other))) )
+	: _Alloc(std::move(__other))
+      { }
+#endif
+    };
+
+  template<typename _Alloc>
+    struct __alloc_value_initializer<_Alloc, false> : public _Alloc
+    {
+#if __cplusplus >= 201103L
+      __alloc_value_initializer() = default;
+
+      __alloc_value_initializer(_Alloc&& __other)
+	noexcept( noexcept(_Alloc(std::move(__other))) )
+	: _Alloc(std::move(__other))
+      { }
+#else
+      __alloc_value_initializer() throw()
+      { }
+#endif
+
+      __alloc_value_initializer(const _Alloc& __other)
+	_GLIBCXX_NOEXCEPT_IF(noexcept(_Alloc(__other)))
+	: _Alloc(__other)
+      { }
+    };
+
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std