2 files changed, 32 insertions, 46 deletions
diff --git a/libcxx/include/__utility/integer_sequence.h b/libcxx/include/__utility/integer_sequence.h
index d1c6e53..329826a 100644
--- a/libcxx/include/__utility/integer_sequence.h
+++ b/libcxx/include/__utility/integer_sequence.h
@@ -17,57 +17,41 @@
 #  pragma GCC system_header
 #endif
 
+#ifndef _LIBCPP_CXX03_LANG
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <size_t...>
-struct __tuple_indices;
+#  if __has_builtin(__make_integer_seq)
+template <template <class _Tp, _Tp...> class _BaseType, class _Tp, _Tp _SequenceSize>
+using __make_integer_sequence_impl _LIBCPP_NODEBUG = __make_integer_seq<_BaseType, _Tp, _SequenceSize>;
+#  else
+template <template <class _Tp, _Tp...> class _BaseType, class _Tp, _Tp _SequenceSize>
+using __make_integer_sequence_impl _LIBCPP_NODEBUG = _BaseType<_Tp, __integer_pack(_SequenceSize)...>;
+#  endif
 
-template <class _IdxType, _IdxType... _Values>
+template <class _Tp, _Tp... _Indices>
 struct __integer_sequence {
-  template <template <class _OIdxType, _OIdxType...> class _ToIndexSeq, class _ToIndexType>
-  using __convert _LIBCPP_NODEBUG = _ToIndexSeq<_ToIndexType, _Values...>;
-
-  template <size_t _Sp>
-  using __to_tuple_indices _LIBCPP_NODEBUG = __tuple_indices<(_Values + _Sp)...>;
+  using value_type = _Tp;
+  static_assert(is_integral<_Tp>::value, "std::integer_sequence can only be instantiated with an integral type");
+  static _LIBCPP_HIDE_FROM_ABI constexpr size_t size() noexcept { return sizeof...(_Indices); }
 };
 
-#if __has_builtin(__make_integer_seq)
-template <size_t _Ep, size_t _Sp>
-using __make_indices_imp _LIBCPP_NODEBUG =
-    typename __make_integer_seq<__integer_sequence, size_t, _Ep - _Sp>::template __to_tuple_indices<_Sp>;
-#elif __has_builtin(__integer_pack)
-template <size_t _Ep, size_t _Sp>
-using __make_indices_imp _LIBCPP_NODEBUG =
-    typename __integer_sequence<size_t, __integer_pack(_Ep - _Sp)...>::template __to_tuple_indices<_Sp>;
-#else
-#  error "No known way to get an integer pack from the compiler"
-#endif
+template <size_t... _Indices>
+using __index_sequence _LIBCPP_NODEBUG = __integer_sequence<size_t, _Indices...>;
 
-#if _LIBCPP_STD_VER >= 14
+template <size_t _SequenceSize>
+using __make_index_sequence _LIBCPP_NODEBUG = __make_integer_sequence_impl<__integer_sequence, size_t, _SequenceSize>;
 
-template <class _Tp, _Tp... _Ip>
-struct integer_sequence {
-  typedef _Tp value_type;
-  static_assert(is_integral<_Tp>::value, "std::integer_sequence can only be instantiated with an integral type");
-  static _LIBCPP_HIDE_FROM_ABI constexpr size_t size() noexcept { return sizeof...(_Ip); }
-};
+#  if _LIBCPP_STD_VER >= 14
+
+template <class _Tp, _Tp... _Indices>
+struct integer_sequence : __integer_sequence<_Tp, _Indices...> {};
 
 template <size_t... _Ip>
 using index_sequence = integer_sequence<size_t, _Ip...>;
 
-#  if __has_builtin(__make_integer_seq)
-
 template <class _Tp, _Tp _Ep>
-using make_integer_sequence _LIBCPP_NODEBUG = __make_integer_seq<integer_sequence, _Tp, _Ep>;
-
-#  elif __has_builtin(__integer_pack)
-
-template <class _Tp, _Tp _SequenceSize>
-using make_integer_sequence _LIBCPP_NODEBUG = integer_sequence<_Tp, __integer_pack(_SequenceSize)...>;
-
-#  else
-#    error "No known way to get an integer pack from the compiler"
-#  endif
+using make_integer_sequence _LIBCPP_NODEBUG = __make_integer_sequence_impl<integer_sequence, _Tp, _Ep>;
 
 template <size_t _Np>
 using make_index_sequence = make_integer_sequence<size_t, _Np>;
@@ -75,16 +59,18 @@ using make_index_sequence = make_integer_sequence<size_t, _Np>;
 template <class... _Tp>
 using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
 
-#  if _LIBCPP_STD_VER >= 20
+#    if _LIBCPP_STD_VER >= 20
 // Executes __func for every element in an index_sequence.
 template <size_t... _Index, class _Function>
 _LIBCPP_HIDE_FROM_ABI constexpr void __for_each_index_sequence(index_sequence<_Index...>, _Function __func) {
   (__func.template operator()<_Index>(), ...);
 }
-#  endif // _LIBCPP_STD_VER >= 20
+#    endif // _LIBCPP_STD_VER >= 20
 
-#endif // _LIBCPP_STD_VER >= 14
+#  endif // _LIBCPP_STD_VER >= 14
 
 _LIBCPP_END_NAMESPACE_STD
 
+#endif // _LIBCPP_CXX03_LANG
+
 #endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
diff --git a/libcxx/include/__utility/pair.h b/libcxx/include/__utility/pair.h
index dbacbce..33694c52 100644
--- a/libcxx/include/__utility/pair.h
+++ b/libcxx/include/__utility/pair.h
@@ -18,7 +18,6 @@
 #include <__fwd/array.h>
 #include <__fwd/pair.h>
 #include <__fwd/tuple.h>
-#include <__tuple/tuple_indices.h>
 #include <__tuple/tuple_like_no_subrange.h>
 #include <__tuple/tuple_size.h>
 #include <__type_traits/common_reference.h>
@@ -40,6 +39,7 @@
 #include <__type_traits/unwrap_ref.h>
 #include <__utility/declval.h>
 #include <__utility/forward.h>
+#include <__utility/integer_sequence.h>
 #include <__utility/move.h>
 #include <__utility/piecewise_construct.h>
 
@@ -225,8 +225,8 @@ struct pair
       : pair(__pc,
              __first_args,
              __second_args,
-             typename __make_tuple_indices<sizeof...(_Args1)>::type(),
-             typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
+             __make_index_sequence<sizeof...(_Args1)>(),
+             __make_index_sequence<sizeof...(_Args2)>()) {}
 
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair&
   operator=(__conditional_t<is_copy_assignable<first_type>::value && is_copy_assignable<second_type>::value,
@@ -440,8 +440,8 @@ private:
   pair(piecewise_construct_t,
        tuple<_Args1...>& __first_args,
        tuple<_Args2...>& __second_args,
-       __tuple_indices<_I1...>,
-       __tuple_indices<_I2...>)
+       __index_sequence<_I1...>,
+       __index_sequence<_I2...>)
       : first(std::forward<_Args1>(std::get<_I1>(__first_args))...),
         second(std::forward<_Args2>(std::get<_I2>(__second_args))...) {}
 #endif