diff --git a/include/boost/core/default_allocator.hpp b/include/boost/core/default_allocator.hpp
index a366f62..554e738 100644
--- a/include/boost/core/default_allocator.hpp
+++ b/include/boost/core/default_allocator.hpp
@@ -9,7 +9,6 @@ Distributed under the Boost Software License, Version 1.0.
 #define BOOST_CORE_DEFAULT_ALLOCATOR_HPP
 
 #include <boost/config.hpp>
-#include <limits>
 #include <new>
 
 #if defined(BOOST_LIBSTDCXX_VERSION) && BOOST_LIBSTDCXX_VERSION < 60000
@@ -82,10 +81,7 @@ struct default_allocator {
         BOOST_NOEXCEPT { }
 
     BOOST_CONSTEXPR std::size_t max_size() const BOOST_NOEXCEPT {
-        return std::numeric_limits<std::ptrdiff_t>::max()
-            < std::numeric_limits<std::size_t>::max() / sizeof(T)
-            ? std::numeric_limits<std::ptrdiff_t>::max()
-            : std::numeric_limits<std::size_t>::max() / sizeof(T);
+        return static_cast<std::size_t>(-1) / (2 < sizeof(T) ? sizeof(T) : 2);
     }
 
 #if !defined(BOOST_NO_EXCEPTIONS)
@@ -125,6 +121,7 @@ struct default_allocator {
     template<class U>
     void destroy(U* p) {
         p->~U();
+        (void)p;
     }
 #endif
 };
diff --git a/test/default_allocator_test.cpp b/test/default_allocator_test.cpp
index e921747..041c52a 100644
--- a/test/default_allocator_test.cpp
+++ b/test/default_allocator_test.cpp
@@ -173,20 +173,11 @@ void test_construct_other()
     (void)a5;
 }
 
-#if defined(PTRDIFF_MAX) && defined(SIZE_MAX)
 template<class T>
 std::size_t max_size()
 {
-    return PTRDIFF_MAX < SIZE_MAX / sizeof(T)
-        ? PTRDIFF_MAX : SIZE_MAX / sizeof(T);
+    return static_cast<std::size_t>(-1) / (2 < sizeof(T) ? sizeof(T) : 2);
 }
-#else
-template<class T>
-std::size_t max_size()
-{
-    return ~static_cast<std::size_t>(0) / sizeof(T);
-}
-#endif
 
 void test_max_size()
 {