diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index d42cd37..97913a6 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -1870,6 +1870,11 @@ GLIBCXX_3.4.22 {
     # std::uncaught_exceptions()
     _ZSt19uncaught_exceptionsv;
 
+    extern "C++"
+    {
+      std::__detail::_Power2_rehash_policy::*;
+    };
+
 } GLIBCXX_3.4.21;
 
 # Symbols in the support library (libsupc++) have their own tag.
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index a9ad7dd..e774044 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -457,6 +457,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /// smallest prime that keeps the load factor small enough.
   struct _Prime_rehash_policy
   {
+    using __has_load_factor = std::true_type;
+
     _Prime_rehash_policy(float __z = 1.0) noexcept
     : _M_max_load_factor(__z), _M_next_resize(0) { }
 
@@ -501,6 +503,69 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     mutable std::size_t	_M_next_resize;
   };
 
+  /// Range hashing function considering that second args is a power of 2.
+  struct _Mask_range_hashing
+  {
+    typedef std::size_t first_argument_type;
+    typedef std::size_t second_argument_type;
+    typedef std::size_t result_type;
+
+    result_type
+    operator()(first_argument_type __num,
+	       second_argument_type __den) const noexcept
+    { return __num & (__den - 1); }
+  };
+
+  /// Rehash policy providing power of 2 bucket numbers. Ease modulo
+  /// operations.
+  struct _Power2_rehash_policy
+  {
+    using __has_load_factor = std::true_type;
+
+    _Power2_rehash_policy(float __z = 1.0) noexcept
+    : _M_max_load_factor(__z), _M_next_resize(0) { }
+
+    float
+    max_load_factor() const noexcept
+    { return _M_max_load_factor; }
+
+    // Return a bucket size no smaller than n.
+    std::size_t
+    _M_next_bkt(std::size_t __n) const;
+
+    // Return a bucket count appropriate for n elements
+    std::size_t
+    _M_bkt_for_elements(std::size_t __n) const
+    { return __builtin_ceil(__n / (long double)_M_max_load_factor); }
+
+    // __n_bkt is current bucket count, __n_elt is current element count,
+    // and __n_ins is number of elements to be inserted.  Do we need to
+    // increase bucket count?  If so, return make_pair(true, n), where n
+    // is the new bucket count.  If not, return make_pair(false, 0).
+    std::pair<bool, std::size_t>
+    _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
+		   std::size_t __n_ins) const;
+
+    typedef std::size_t _State;
+
+    _State
+    _M_state() const
+    { return _M_next_resize; }
+
+    void
+    _M_reset() noexcept
+    { _M_next_resize = 0; }
+
+    void
+    _M_reset(_State __state)
+    { _M_next_resize = __state; }
+
+    static const std::size_t _S_growth_factor = 2;
+
+    float		_M_max_load_factor;
+    mutable std::size_t	_M_next_resize;
+  };
+
   // Base classes for std::_Hashtable.  We define these base classes
   // because in some cases we want to do different things depending on
   // the value of a policy class.  In some cases the policy class
@@ -775,8 +840,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   typename _ExtractKey, typename _Equal,
 	   typename _H1, typename _H2, typename _Hash,
 	   typename _RehashPolicy, typename _Traits,
-	   bool _Constant_iterators = _Traits::__constant_iterators::value,
-	   bool _Unique_keys = _Traits::__unique_keys::value>
+	   bool _Constant_iterators = _Traits::__constant_iterators::value>
     struct _Insert;
 
   /// Specialization.
@@ -785,65 +849,30 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   typename _H1, typename _H2, typename _Hash,
 	   typename _RehashPolicy, typename _Traits>
     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
-		   _RehashPolicy, _Traits, true, true>
+		   _RehashPolicy, _Traits, true>
     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
 			   _H1, _H2, _Hash, _RehashPolicy, _Traits>
     {
       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
 					_Equal, _H1, _H2, _Hash,
 					_RehashPolicy, _Traits>;
-      using value_type = typename __base_type::value_type;
-      using iterator = typename __base_type::iterator;
-      using const_iterator =  typename __base_type::const_iterator;
-
-      using __unique_keys = typename __base_type::__unique_keys;
-      using __hashtable = typename __base_type::__hashtable;
-      using __node_gen_type = typename __base_type::__node_gen_type;
-
-      using __base_type::insert;
 
-      std::pair<iterator, bool>
-      insert(value_type&& __v)
-      {
-	__hashtable& __h = this->_M_conjure_hashtable();
-	__node_gen_type __node_gen(__h);
-	return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
-      }
-
-      iterator
-      insert(const_iterator __hint, value_type&& __v)
-      {
-	__hashtable& __h = this->_M_conjure_hashtable();
-	__node_gen_type __node_gen(__h);
-	return __h._M_insert(__hint, std::move(__v), __node_gen,
-			     __unique_keys());
-      }
-    };
+      using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
+					       _Equal, _H1, _H2, _Hash,
+					       _Traits>;
 
-  /// Specialization.
-  template<typename _Key, typename _Value, typename _Alloc,
-	   typename _ExtractKey, typename _Equal,
-	   typename _H1, typename _H2, typename _Hash,
-	   typename _RehashPolicy, typename _Traits>
-    struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
-		   _RehashPolicy, _Traits, true, false>
-    : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
-			   _H1, _H2, _Hash, _RehashPolicy, _Traits>
-    {
-      using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
-					_Equal, _H1, _H2, _Hash,
-					_RehashPolicy, _Traits>;
       using value_type = typename __base_type::value_type;
       using iterator = typename __base_type::iterator;
       using const_iterator =  typename __base_type::const_iterator;
 
       using __unique_keys = typename __base_type::__unique_keys;
+      using __ireturn_type = typename __hashtable_base::__ireturn_type;
       using __hashtable = typename __base_type::__hashtable;
       using __node_gen_type = typename __base_type::__node_gen_type;
 
       using __base_type::insert;
 
-      iterator
+      __ireturn_type
       insert(value_type&& __v)
       {
 	__hashtable& __h = this->_M_conjure_hashtable();
@@ -865,9 +894,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Key, typename _Value, typename _Alloc,
 	   typename _ExtractKey, typename _Equal,
 	   typename _H1, typename _H2, typename _Hash,
-	   typename _RehashPolicy, typename _Traits, bool _Unique_keys>
+	   typename _RehashPolicy, typename _Traits>
     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
-		   _RehashPolicy, _Traits, false, _Unique_keys>
+		   _RehashPolicy, _Traits, false>
     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
 			   _H1, _H2, _Hash, _RehashPolicy, _Traits>
     {
@@ -911,28 +940,46 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	}
    };
 
+  template<typename _Policy>
+    using __has_load_factor = typename _Policy::__has_load_factor;
+
   /**
    *  Primary class template  _Rehash_base.
    *
    *  Give hashtable the max_load_factor functions and reserve iff the
-   *  rehash policy is _Prime_rehash_policy.
+   *  rehash policy supports it.
   */
   template<typename _Key, typename _Value, typename _Alloc,
 	   typename _ExtractKey, typename _Equal,
 	   typename _H1, typename _H2, typename _Hash,
-	   typename _RehashPolicy, typename _Traits>
+	   typename _RehashPolicy, typename _Traits,
+	   typename =
+	     __detected_or_t<std::false_type, __has_load_factor, _RehashPolicy>>
     struct _Rehash_base;
 
-  /// Specialization.
+  /// Specialization when rehash policy doesn't provide load factor management.
   template<typename _Key, typename _Value, typename _Alloc,
 	   typename _ExtractKey, typename _Equal,
-	   typename _H1, typename _H2, typename _Hash, typename _Traits>
+	   typename _H1, typename _H2, typename _Hash,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		      _H1, _H2, _Hash, _RehashPolicy, _Traits,
+		      std::false_type>
+    {
+    };
+
+  /// Specialization when rehash policy provide load factor management.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _H1, typename _H2, typename _Hash,
+	   typename _RehashPolicy, typename _Traits>
     struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
-			_H1, _H2, _Hash, _Prime_rehash_policy, _Traits>
+			_H1, _H2, _Hash, _RehashPolicy, _Traits,
+			std::true_type>
     {
       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
 				     _Equal, _H1, _H2, _Hash,
-				     _Prime_rehash_policy, _Traits>;
+				     _RehashPolicy, _Traits>;
 
       float
       max_load_factor() const noexcept
@@ -945,7 +992,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       max_load_factor(float __z)
       {
 	__hashtable* __this = static_cast<__hashtable*>(this);
-	__this->__rehash_policy(_Prime_rehash_policy(__z));
+	__this->__rehash_policy(_RehashPolicy(__z));
       }
 
       void
diff --git a/libstdc++-v3/src/c++11/hashtable_c++0x.cc b/libstdc++-v3/src/c++11/hashtable_c++0x.cc
index 69f999f..7b2fd76 100644
--- a/libstdc++-v3/src/c++11/hashtable_c++0x.cc
+++ b/libstdc++-v3/src/c++11/hashtable_c++0x.cc
@@ -32,6 +32,81 @@
 #include <ext/alloc_traits.h>
 #include <bits/hashtable_policy.h>
 
+namespace
+{
+  const unsigned long __power2_list[] = // 32 or 64
+  {
+    1ul << 0,
+    1ul << 1,
+    1ul << 2,
+    1ul << 3,
+    1ul << 4,
+    1ul << 5,
+    1ul << 6,
+    1ul << 7,
+    1ul << 8,
+    1ul << 9,
+    1ul << 10,
+    1ul << 11,
+    1ul << 12,
+    1ul << 13,
+    1ul << 14,
+    1ul << 15,
+    1ul << 16,
+    1ul << 17,
+    1ul << 18,
+    1ul << 19,
+    1ul << 20,
+    1ul << 21,
+    1ul << 22,
+    1ul << 23,
+    1ul << 24,
+    1ul << 25,
+    1ul << 26,
+    1ul << 27,
+    1ul << 28,
+    1ul << 29,
+    1ul << 30,
+    1ul << 31,
+#if __SIZEOF_LONG__ != 8
+    1ul << 32
+#else
+    1ul << 32,
+    1ul << 33,
+    1ul << 34,
+    1ul << 35,
+    1ul << 36,
+    1ul << 37,
+    1ul << 38,
+    1ul << 39,
+    1ul << 40,
+    1ul << 41,
+    1ul << 42,
+    1ul << 43,
+    1ul << 44,
+    1ul << 45,
+    1ul << 46,
+    1ul << 47,
+    1ul << 48,
+    1ul << 49,
+    1ul << 50,
+    1ul << 51,
+    1ul << 52,
+    1ul << 53,
+    1ul << 54,
+    1ul << 55,
+    1ul << 56,
+    1ul << 57,
+    1ul << 58,
+    1ul << 59,
+    1ul << 60,
+    1ul << 61,
+    1ul << 62,
+    1ul << 63
+#endif
+  };
+}
+
 namespace std _GLIBCXX_VISIBILITY(default)
 {
 #include "../shared/hashtable-aux.cc"
@@ -96,6 +171,62 @@ namespace __detail
       return std::make_pair(false, 0);
   }
 
+  // Return a prime no smaller than n.
+  std::size_t
+  _Power2_rehash_policy::_M_next_bkt(std::size_t __n) const
+  {
+    // Optimize lookups involving the first elements of __prime_list.
+    // (useful to speed-up, eg, constructors)
+    static const unsigned char __fast_bkt[12]
+      = { 2, 2, 2, 4, 8, 8, 8, 8, 16, 16, 16, 16 };
+
+    if (__n <= 11)
+      {
+	_M_next_resize =
+	  __builtin_ceil(__fast_bkt[__n] * (long double)_M_max_load_factor);
+	return __fast_bkt[__n];
+      }
+
+    constexpr auto __n_power2
+      = sizeof(__power2_list) / sizeof(unsigned long) - 1;
+    const unsigned long* __next_bkt =
+      std::lower_bound(__power2_list + 4, __power2_list + __n_power2, __n);
+    _M_next_resize =
+      __builtin_ceil(*__next_bkt * (long double)_M_max_load_factor);
+    return *__next_bkt;
+  }
+
+  // Finds the smallest prime p such that alpha p > __n_elt + __n_ins.
+  // If p > __n_bkt, return make_pair(true, p); otherwise return
+  // make_pair(false, 0).  In principle this isn't very different from
+  // _M_bkt_for_elements.
+
+  // The only tricky part is that we're caching the element count at
+  // which we need to rehash, so we don't have to do a floating-point
+  // multiply for every insertion.
+
+  std::pair<bool, std::size_t>
+  _Power2_rehash_policy::
+  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
+		 std::size_t __n_ins) const
+  {
+    if (__n_elt + __n_ins >= _M_next_resize)
+      {
+	long double __min_bkts = (__n_elt + __n_ins)
+				   / (long double)_M_max_load_factor;
+	if (__min_bkts >= __n_bkt)
+	  return std::make_pair(true,
+	    _M_next_bkt(std::max<std::size_t>(__builtin_floor(__min_bkts) + 1,
+					      __n_bkt * _S_growth_factor)));
+
+	_M_next_resize
+	  = __builtin_floor(__n_bkt * (long double)_M_max_load_factor);
+	return std::make_pair(false, 0);
+      }
+    else
+      return std::make_pair(false, 0);
+  }
+
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace __detail
 } // namespace std
diff --git a/libstdc++-v3/testsuite/performance/23_containers/insert/54075.cc b/libstdc++-v3/testsuite/performance/23_containers/insert/54075.cc
index ef956a0..a07d552 100644
--- a/libstdc++-v3/testsuite/performance/23_containers/insert/54075.cc
+++ b/libstdc++-v3/testsuite/performance/23_containers/insert/54075.cc
@@ -127,7 +127,27 @@ template<bool cache>
   using __umset = std::__umset_hashtable<Foo, HashFunction,
 					 std::equal_to<Foo>,
 					 std::allocator<Foo>,
-					 std::__uset_traits<cache>>;
+					 std::__umset_traits<cache>>;
+
+template<bool cache>
+  using __uset2 =
+	      std::_Hashtable<Foo, Foo, std::allocator<Foo>,
+			      std::__detail::_Identity,
+			      std::equal_to<Foo>, HashFunction,
+			      std::__detail::_Mask_range_hashing,
+			      std::__detail::_Default_ranged_hash,
+			      std::__detail::_Power2_rehash_policy,
+			      std::__uset_traits<cache>>;
+
+template<bool cache>
+  using __umset2 =
+	      std::_Hashtable<Foo, Foo, std::allocator<Foo>,
+			      std::__detail::_Identity,
+			      std::equal_to<Foo>, HashFunction,
+			      std::__detail::_Mask_range_hashing,
+			      std::__detail::_Default_ranged_hash,
+			      std::__detail::_Power2_rehash_policy,
+			      std::__umset_traits<cache>>;
 
 int main()
 {
@@ -181,6 +201,19 @@ int main()
   stop_counters(time, resource);
   report_performance(__FILE__, "std benches", time, resource);
 
+  start_counters(time, resource);
+  bench<__uset2<false>>(
+	"std::unordered_set2 without hash code cached ", foos);
+  bench<__uset2<true>>(
+	"std::unordered_set2 with hash code cached ", foos);
+  bench<__umset2<false>>(
+	"std::unordered_multiset2 without hash code cached ", foos);
+  bench<__umset2<true>>(
+	"std::unordered_multiset2 with hash code cached ", foos);
+
+  stop_counters(time, resource);
+  report_performance(__FILE__, "std2 benches", time, resource);
+
   bench<std::unordered_set<Foo, HashFunction>>(
 	"std::unordered_set default cache ", foos);
   bench<std::unordered_multiset<Foo, HashFunction>>(
diff --git a/libstdc++-v3/testsuite/performance/23_containers/insert_erase/41975.cc b/libstdc++-v3/testsuite/performance/23_containers/insert_erase/41975.cc
index 9846104..4b29fde 100644
--- a/libstdc++-v3/testsuite/performance/23_containers/insert_erase/41975.cc
+++ b/libstdc++-v3/testsuite/performance/23_containers/insert_erase/41975.cc
@@ -177,6 +177,16 @@ template<bool cache>
 					cache>;
 
 template<bool cache>
+  using __uset2 =
+	      std::_Hashtable<int, int, std::allocator<int>,
+			      std::__detail::_Identity,
+			      std::equal_to<int>, std::hash<int>,
+			      std::__detail::_Mask_range_hashing,
+			      std::__detail::_Default_ranged_hash,
+			      std::__detail::_Power2_rehash_policy,
+			      std::__uset_traits<cache>>;
+
+template<bool cache>
   using __str_uset = 
 	      std::__uset_hashtable<std::string, std::hash<std::string>,
 				    std::equal_to<std::string>,
@@ -190,6 +200,16 @@ template<bool cache>
 					std::allocator<std::string>,
 					cache>;
 
+template<bool cache>
+  using __str_uset2 =
+	      std::_Hashtable<std::string, std::string, std::allocator<std::string>,
+			      std::__detail::_Identity,
+			      std::equal_to<std::string>, std::hash<std::string>,
+			      std::__detail::_Mask_range_hashing,
+			      std::__detail::_Default_ranged_hash,
+			      std::__detail::_Power2_rehash_policy,
+			      std::__uset_traits<cache>>;
+
 int main()
 {
   bench<__tr1_uset<false>>(
@@ -202,6 +222,10 @@ int main()
 	"std::unordered_set<int> with hash code cached");
   bench<std::unordered_set<int>>(
 	"std::unordered_set<int> default cache");
+  bench<__uset2<false>>(
+	"std::unordered_set2<int> without hash code cached");
+  bench<__uset2<true>>(
+	"std::unordered_set2<int> with hash code cached");
   bench_str<__tr1_str_uset<false>>(
 	"std::tr1::unordered_set<string> without hash code cached");
   bench_str<__tr1_str_uset<true>>(
@@ -210,7 +234,11 @@ int main()
 	"std::unordered_set<string> without hash code cached");
   bench_str<__str_uset<true>>(
 	"std::unordered_set<string> with hash code cached");
-    bench_str<std::unordered_set<std::string>>(
+  bench_str<std::unordered_set<std::string>>(
 	"std::unordered_set<string> default cache");
+  bench_str<__str_uset2<false>>(
+	"std::unordered_set2<string> without hash code cached");
+  bench_str<__str_uset2<true>>(
+	"std::unordered_set2<string> with hash code cached");
   return 0;
 }
