[libcxx-commits] [libcxx] 69d5a66 - [libcxx][modularisation] splits `<utility>` into self-contained headers

[Christopher Di Bella via libcxx-commits]

Author: Christopher Di Bella
Date: 2021-06-25T00:29:01Z
New Revision: 69d5a6662115499198ebfa07a081e98a6ce4b915

URL: https://github.com/llvm/llvm-project/commit/69d5a6662115499198ebfa07a081e98a6ce4b915
DIFF: https://github.com/llvm/llvm-project/commit/69d5a6662115499198ebfa07a081e98a6ce4b915.diff

LOG: [libcxx][modularisation] splits `<utility>` into self-contained headers

* moves `std::hash` and `std::unary_function` into `__functional`
* Everything else goes into `__utility/${NAME}.h`

Differential Revision: https://reviews.llvm.org/D104002

Added: 
    libcxx/include/__functional/hash.h
    libcxx/include/__functional/unary_function.h
    libcxx/include/__functional/unwrap_ref.h
    libcxx/include/__utility/as_const.h
    libcxx/include/__utility/cmp.h
    libcxx/include/__utility/exchange.h
    libcxx/include/__utility/in_place.h
    libcxx/include/__utility/integer_sequence.h
    libcxx/include/__utility/pair.h
    libcxx/include/__utility/piecewise_construct.h
    libcxx/include/__utility/rel_ops.h

Modified: 
    libcxx/include/CMakeLists.txt
    libcxx/include/__functional_base
    libcxx/include/__memory/unique_ptr.h
    libcxx/include/__tree
    libcxx/include/deque
    libcxx/include/functional
    libcxx/include/module.modulemap
    libcxx/include/span
    libcxx/include/tuple
    libcxx/include/utility
    libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp
    libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
    libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
    libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
    libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
    libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
    libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
    libcxx/test/std/utilities/utility/utility.underlying/to_underlying.pass.cpp
    libcxx/test/support/poisoned_hash_helper.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index faaf9325fad68..a594b57866ab9 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -107,6 +107,9 @@ set(files
   __functional_03
   __functional_base
   __functional_base_03
+  __functional/hash.h
+  __functional/unary_function.h
+  __functional/unwrap_ref.h
   __hash_table
   __iterator/advance.h
   __iterator/concepts.h
@@ -160,9 +163,17 @@ set(files
   __tuple
   __undef_macros
   __utility/__decay_copy.h
+  __utility/as_const.h
+  __utility/cmp.h
   __utility/declval.h
+  __utility/exchange.h
   __utility/forward.h
+  __utility/in_place.h
+  __utility/integer_sequence.h
   __utility/move.h
+  __utility/pair.h
+  __utility/piecewise_construct.h
+  __utility/rel_ops.h
   __utility/swap.h
   __utility/to_underlying.h
   algorithm

diff  --git a/libcxx/include/__functional/hash.h b/libcxx/include/__functional/hash.h
new file mode 100644
index 0000000000000..e169ebc6ea598
--- /dev/null
+++ b/libcxx/include/__functional/hash.h
@@ -0,0 +1,872 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_HASH_H
+#define _LIBCPP___FUNCTIONAL_HASH_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+#include <__tuple>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/swap.h>
+#include <cstdint>
+#include <cstring>
+#include <cstddef>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_Size
+__loadword(const void* __p)
+{
+    _Size __r;
+    _VSTD::memcpy(&__r, __p, sizeof(__r));
+    return __r;
+}
+
+// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
+// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
+// multiplication, which can be very slow on 32-bit systems.
+template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
+struct __murmur2_or_cityhash;
+
+template <class _Size>
+struct __murmur2_or_cityhash<_Size, 32>
+{
+    inline _Size operator()(const void* __key, _Size __len)
+         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
+};
+
+// murmur2
+template <class _Size>
+_Size
+__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
+{
+    const _Size __m = 0x5bd1e995;
+    const _Size __r = 24;
+    _Size __h = __len;
+    const unsigned char* __data = static_cast<const unsigned char*>(__key);
+    for (; __len >= 4; __data += 4, __len -= 4)
+    {
+        _Size __k = __loadword<_Size>(__data);
+        __k *= __m;
+        __k ^= __k >> __r;
+        __k *= __m;
+        __h *= __m;
+        __h ^= __k;
+    }
+    switch (__len)
+    {
+    case 3:
+        __h ^= __data[2] << 16;
+        _LIBCPP_FALLTHROUGH();
+    case 2:
+        __h ^= __data[1] << 8;
+        _LIBCPP_FALLTHROUGH();
+    case 1:
+        __h ^= __data[0];
+        __h *= __m;
+    }
+    __h ^= __h >> 13;
+    __h *= __m;
+    __h ^= __h >> 15;
+    return __h;
+}
+
+template <class _Size>
+struct __murmur2_or_cityhash<_Size, 64>
+{
+    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
+
+ private:
+  // Some primes between 2^63 and 2^64.
+  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
+  static const _Size __k1 = 0xb492b66fbe98f273ULL;
+  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
+  static const _Size __k3 = 0xc949d7c7509e6557ULL;
+
+  static _Size __rotate(_Size __val, int __shift) {
+    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
+  }
+
+  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
+    return (__val >> __shift) | (__val << (64 - __shift));
+  }
+
+  static _Size __shift_mix(_Size __val) {
+    return __val ^ (__val >> 47);
+  }
+
+  static _Size __hash_len_16(_Size __u, _Size __v)
+     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    const _Size __mul = 0x9ddfea08eb382d69ULL;
+    _Size __a = (__u ^ __v) * __mul;
+    __a ^= (__a >> 47);
+    _Size __b = (__v ^ __a) * __mul;
+    __b ^= (__b >> 47);
+    __b *= __mul;
+    return __b;
+  }
+
+  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
+     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    if (__len > 8) {
+      const _Size __a = __loadword<_Size>(__s);
+      const _Size __b = __loadword<_Size>(__s + __len - 8);
+      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
+    }
+    if (__len >= 4) {
+      const uint32_t __a = __loadword<uint32_t>(__s);
+      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
+      return __hash_len_16(__len + (__a << 3), __b);
+    }
+    if (__len > 0) {
+      const unsigned char __a = __s[0];
+      const unsigned char __b = __s[__len >> 1];
+      const unsigned char __c = __s[__len - 1];
+      const uint32_t __y = static_cast<uint32_t>(__a) +
+                           (static_cast<uint32_t>(__b) << 8);
+      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
+      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
+    }
+    return __k2;
+  }
+
+  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
+     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    const _Size __a = __loadword<_Size>(__s) * __k1;
+    const _Size __b = __loadword<_Size>(__s + 8);
+    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
+    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
+    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
+                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
+  }
+
+  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
+  // Callers do best to use "random-looking" values for a and b.
+  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
+      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
+        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    __a += __w;
+    __b = __rotate(__b + __a + __z, 21);
+    const _Size __c = __a;
+    __a += __x;
+    __a += __y;
+    __b += __rotate(__a, 44);
+    return pair<_Size, _Size>(__a + __z, __b + __c);
+  }
+
+  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
+  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
+      const char* __s, _Size __a, _Size __b)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
+                                         __loadword<_Size>(__s + 8),
+                                         __loadword<_Size>(__s + 16),
+                                         __loadword<_Size>(__s + 24),
+                                         __a,
+                                         __b);
+  }
+
+  // Return an 8-byte hash for 33 to 64 bytes.
+  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    _Size __z = __loadword<_Size>(__s + 24);
+    _Size __a = __loadword<_Size>(__s) +
+                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
+    _Size __b = __rotate(__a + __z, 52);
+    _Size __c = __rotate(__a, 37);
+    __a += __loadword<_Size>(__s + 8);
+    __c += __rotate(__a, 7);
+    __a += __loadword<_Size>(__s + 16);
+    _Size __vf = __a + __z;
+    _Size __vs = __b + __rotate(__a, 31) + __c;
+    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
+    __z += __loadword<_Size>(__s + __len - 8);
+    __b = __rotate(__a + __z, 52);
+    __c = __rotate(__a, 37);
+    __a += __loadword<_Size>(__s + __len - 24);
+    __c += __rotate(__a, 7);
+    __a += __loadword<_Size>(__s + __len - 16);
+    _Size __wf = __a + __z;
+    _Size __ws = __b + __rotate(__a, 31) + __c;
+    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
+    return __shift_mix(__r * __k0 + __vs) * __k2;
+  }
+};
+
+// cityhash64
+template <class _Size>
+_Size
+__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
+{
+  const char* __s = static_cast<const char*>(__key);
+  if (__len <= 32) {
+    if (__len <= 16) {
+      return __hash_len_0_to_16(__s, __len);
+    } else {
+      return __hash_len_17_to_32(__s, __len);
+    }
+  } else if (__len <= 64) {
+    return __hash_len_33_to_64(__s, __len);
+  }
+
+  // For strings over 64 bytes we hash the end first, and then as we
+  // loop we keep 56 bytes of state: v, w, x, y, and z.
+  _Size __x = __loadword<_Size>(__s + __len - 40);
+  _Size __y = __loadword<_Size>(__s + __len - 16) +
+              __loadword<_Size>(__s + __len - 56);
+  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
+                          __loadword<_Size>(__s + __len - 24));
+  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
+  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
+  __x = __x * __k1 + __loadword<_Size>(__s);
+
+  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
+  __len = (__len - 1) & ~static_cast<_Size>(63);
+  do {
+    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
+    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
+    __x ^= __w.second;
+    __y += __v.first + __loadword<_Size>(__s + 40);
+    __z = __rotate(__z + __w.first, 33) * __k1;
+    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
+    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
+                                        __y + __loadword<_Size>(__s + 16));
+    _VSTD::swap(__z, __x);
+    __s += 64;
+    __len -= 64;
+  } while (__len != 0);
+  return __hash_len_16(
+      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
+      __hash_len_16(__v.second, __w.second) + __x);
+}
+
+template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
+struct __scalar_hash;
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 0>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp    __t;
+            size_t __a;
+        } __u;
+        __u.__a = 0;
+        __u.__t = __v;
+        return __u.__a;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 1>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp    __t;
+            size_t __a;
+        } __u;
+        __u.__t = __v;
+        return __u.__a;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 2>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+            } __s;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 3>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+                size_t __c;
+            } __s;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 4>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+                size_t __c;
+                size_t __d;
+            } __s;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+struct _PairT {
+  size_t first;
+  size_t second;
+};
+
+_LIBCPP_INLINE_VISIBILITY
+inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
+    typedef __scalar_hash<_PairT> _HashT;
+    const _PairT __p = {__lhs, __rhs};
+    return _HashT()(__p);
+}
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp*, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp* __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp* __t;
+            size_t __a;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<bool>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<bool, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<signed char>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<signed char, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef signed char argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned char, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned char argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char8_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char8_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+#endif // !_LIBCPP_HAS_NO_CHAR8_T
+
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char16_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char16_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char32_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char32_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<wchar_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef wchar_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<short>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<short, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef short argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned short, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned short argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<int>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<int, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef int argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned int, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned int argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<long>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<long, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef long argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned long, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned long argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<long long>
+    : public __scalar_hash<long long>
+{
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
+    : public __scalar_hash<unsigned long long>
+{
+};
+
+#ifndef _LIBCPP_HAS_NO_INT128
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
+    : public __scalar_hash<__int128_t>
+{
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
+    : public __scalar_hash<__uint128_t>
+{
+};
+
+#endif
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<float>
+    : public __scalar_hash<float>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(float __v) const _NOEXCEPT
+    {
+        // -0.0 and 0.0 should return same hash
+       if (__v == 0.0f)
+           return 0;
+        return __scalar_hash<float>::operator()(__v);
+    }
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<double>
+    : public __scalar_hash<double>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(double __v) const _NOEXCEPT
+    {
+        // -0.0 and 0.0 should return same hash
+       if (__v == 0.0)
+           return 0;
+        return __scalar_hash<double>::operator()(__v);
+    }
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<long double>
+    : public __scalar_hash<long double>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(long double __v) const _NOEXCEPT
+    {
+        // -0.0 and 0.0 should return same hash
+        if (__v == 0.0L)
+            return 0;
+#if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
+        // Zero out padding bits
+        union
+        {
+            long double __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+                size_t __c;
+                size_t __d;
+            } __s;
+        } __u;
+        __u.__s.__a = 0;
+        __u.__s.__b = 0;
+        __u.__s.__c = 0;
+        __u.__s.__d = 0;
+        __u.__t = __v;
+        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
+#elif defined(__x86_64__)
+        // Zero out padding bits
+        union
+        {
+            long double __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+            } __s;
+        } __u;
+        __u.__s.__a = 0;
+        __u.__s.__b = 0;
+        __u.__t = __v;
+        return __u.__s.__a ^ __u.__s.__b;
+#else
+        return __scalar_hash<long double>::operator()(__v);
+#endif
+    }
+};
+
+#if _LIBCPP_STD_VER > 11
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp, bool = is_enum<_Tp>::value>
+struct _LIBCPP_TEMPLATE_VIS __enum_hash
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        typedef typename underlying_type<_Tp>::type type;
+        return hash<type>{}(static_cast<type>(__v));
+    }
+};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
+    __enum_hash() = delete;
+    __enum_hash(__enum_hash const&) = delete;
+    __enum_hash& operator=(__enum_hash const&) = delete;
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
+{
+};
+#endif
+
+#if _LIBCPP_STD_VER > 14
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+  : public unary_function<nullptr_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef nullptr_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(nullptr_t) const _NOEXCEPT {
+        return 662607004ull;
+    }
+};
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Key, class _Hash>
+using __check_hash_requirements _LIBCPP_NODEBUG_TYPE  = integral_constant<bool,
+    is_copy_constructible<_Hash>::value &&
+    is_move_constructible<_Hash>::value &&
+    __invokable_r<size_t, _Hash, _Key const&>::value
+>;
+
+template <class _Key, class _Hash = hash<_Key> >
+using __has_enabled_hash _LIBCPP_NODEBUG_TYPE = integral_constant<bool,
+    __check_hash_requirements<_Key, _Hash>::value &&
+    is_default_constructible<_Hash>::value
+>;
+
+#if _LIBCPP_STD_VER > 14
+template <class _Type, class>
+using __enable_hash_helper_imp _LIBCPP_NODEBUG_TYPE  = _Type;
+
+template <class _Type, class ..._Keys>
+using __enable_hash_helper _LIBCPP_NODEBUG_TYPE  = __enable_hash_helper_imp<_Type,
+  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
+>;
+#else
+template <class _Type, class ...>
+using __enable_hash_helper _LIBCPP_NODEBUG_TYPE = _Type;
+#endif
+
+#endif // !_LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FUNCTIONAL_HASH_H

diff  --git a/libcxx/include/__functional/unary_function.h b/libcxx/include/__functional/unary_function.h
new file mode 100644
index 0000000000000..8084ef4b03434
--- /dev/null
+++ b/libcxx/include/__functional/unary_function.h
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_UNARY_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_UNARY_FUNCTION_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Arg, class _Result>
+struct _LIBCPP_TEMPLATE_VIS unary_function
+{
+    typedef _Arg    argument_type;
+    typedef _Result result_type;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FUNCTIONAL_UNARY_FUNCTION_H

diff  --git a/libcxx/include/__functional/unwrap_ref.h b/libcxx/include/__functional/unwrap_ref.h
new file mode 100644
index 0000000000000..85c0c20ee7e0f
--- /dev/null
+++ b/libcxx/include/__functional/unwrap_ref.h
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_UNWRAP_REF_H
+#define _LIBCPP___FUNCTIONAL_UNWRAP_REF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct __unwrap_reference { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
+
+template <class _Tp>
+class reference_wrapper;
+
+template <class _Tp>
+struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
+
+template <class _Tp>
+struct decay;
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp>
+struct unwrap_reference : __unwrap_reference<_Tp> { };
+
+template <class _Tp>
+struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
+#endif // > C++17
+
+template <class _Tp>
+struct __unwrap_ref_decay
+#if _LIBCPP_STD_VER > 17
+    : unwrap_ref_decay<_Tp>
+#else
+    : __unwrap_reference<typename decay<_Tp>::type>
+#endif
+{ };
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FUNCTIONAL_UNWRAP_REF_H

diff  --git a/libcxx/include/__functional_base b/libcxx/include/__functional_base
index b6f2efdfe9cbc..479dfcf841b24 100644
--- a/libcxx/include/__functional_base
+++ b/libcxx/include/__functional_base
@@ -11,6 +11,7 @@
 #define _LIBCPP_FUNCTIONAL_BASE
 
 #include <__config>
+#include <__functional/unary_function.h>
 #include <exception>
 #include <new>
 #include <type_traits>

diff  --git a/libcxx/include/__memory/unique_ptr.h b/libcxx/include/__memory/unique_ptr.h
index 56a363779c88d..d730fc9ef4e5f 100644
--- a/libcxx/include/__memory/unique_ptr.h
+++ b/libcxx/include/__memory/unique_ptr.h
@@ -12,6 +12,7 @@
 
 #include <__config>
 #include <__functional_base> // std::less
+#include <__functional/hash.h>
 #include <__memory/allocator_traits.h> // __pointer
 #include <__memory/compressed_pair.h>
 #include <__utility/forward.h>

diff  --git a/libcxx/include/__tree b/libcxx/include/__tree
index 5f9ba8be79711..6113322ed99df 100644
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -14,6 +14,7 @@
 #include <__utility/forward.h>
 #include <algorithm>
 #include <iterator>
+#include <limits>
 #include <memory>
 #include <stdexcept>
 

diff  --git a/libcxx/include/__utility/as_const.h b/libcxx/include/__utility/as_const.h
new file mode 100644
index 0000000000000..2f23eb431efae
--- /dev/null
+++ b/libcxx/include/__utility/as_const.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_AS_CONST_H
+#define _LIBCPP___UTILITY_AS_CONST_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
+
+template <class _Tp>
+void as_const(const _Tp&&) = delete;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_AS_CONST_H

diff  --git a/libcxx/include/__utility/cmp.h b/libcxx/include/__utility/cmp.h
new file mode 100644
index 0000000000000..a14e373c3f4b3
--- /dev/null
+++ b/libcxx/include/__utility/cmp.h
@@ -0,0 +1,107 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_CMP_H
+#define _LIBCPP___UTILITY_CMP_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+template<class _Tp, class... _Up>
+struct _IsSameAsAny : _Or<_IsSame<_Tp, _Up>...> {};
+
+template<class _Tp>
+concept __is_safe_integral_cmp = is_integral_v<_Tp> &&
+                      !_IsSameAsAny<_Tp, bool, char,
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+                                    char8_t,
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+                                    char16_t, char32_t,
+#endif
+                                    wchar_t>::value;
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_equal(_Tp __t, _Up __u) noexcept
+{
+  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+    return __t == __u;
+  else if constexpr (is_signed_v<_Tp>)
+    return __t < 0 ? false : make_unsigned_t<_Tp>(__t) == __u;
+  else
+    return __u < 0 ? false : __t == make_unsigned_t<_Up>(__u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_not_equal(_Tp __t, _Up __u) noexcept
+{
+  return !_VSTD::cmp_equal(__t, __u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_less(_Tp __t, _Up __u) noexcept
+{
+  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+    return __t < __u;
+  else if constexpr (is_signed_v<_Tp>)
+    return __t < 0 ? true : make_unsigned_t<_Tp>(__t) < __u;
+  else
+    return __u < 0 ? false : __t < make_unsigned_t<_Up>(__u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_greater(_Tp __t, _Up __u) noexcept
+{
+  return _VSTD::cmp_less(__u, __t);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_less_equal(_Tp __t, _Up __u) noexcept
+{
+  return !_VSTD::cmp_greater(__t, __u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_greater_equal(_Tp __t, _Up __u) noexcept
+{
+  return !_VSTD::cmp_less(__t, __u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool in_range(_Up __u) noexcept
+{
+  return _VSTD::cmp_less_equal(__u, numeric_limits<_Tp>::max()) &&
+         _VSTD::cmp_greater_equal(__u, numeric_limits<_Tp>::min());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_CMP_H

diff  --git a/libcxx/include/__utility/exchange.h b/libcxx/include/__utility/exchange.h
new file mode 100644
index 0000000000000..4d5211d94ad14
--- /dev/null
+++ b/libcxx/include/__utility/exchange.h
@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_EXCHANGE_H
+#define _LIBCPP___UTILITY_EXCHANGE_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 11
+template<class _T1, class _T2 = _T1>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_T1 exchange(_T1& __obj, _T2 && __new_value)
+{
+    _T1 __old_value = _VSTD::move(__obj);
+    __obj = _VSTD::forward<_T2>(__new_value);
+    return __old_value;
+}
+#endif // _LIBCPP_STD_VER > 11
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_EXCHANGE_H

diff  --git a/libcxx/include/__utility/in_place.h b/libcxx/include/__utility/in_place.h
new file mode 100644
index 0000000000000..964d083327475
--- /dev/null
+++ b/libcxx/include/__utility/in_place.h
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_IN_PLACE_H
+#define _LIBCPP___UTILITY_IN_PLACE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+struct _LIBCPP_TYPE_VIS in_place_t {
+    explicit in_place_t() = default;
+};
+_LIBCPP_INLINE_VAR constexpr in_place_t in_place{};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
+    explicit in_place_type_t() = default;
+};
+template <class _Tp>
+_LIBCPP_INLINE_VAR constexpr in_place_type_t<_Tp> in_place_type{};
+
+template <size_t _Idx>
+struct _LIBCPP_TEMPLATE_VIS in_place_index_t {
+    explicit in_place_index_t() = default;
+};
+template <size_t _Idx>
+_LIBCPP_INLINE_VAR constexpr in_place_index_t<_Idx> in_place_index{};
+
+template <class _Tp> struct __is_inplace_type_imp : false_type {};
+template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
+
+template <class _Tp>
+using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
+
+template <class _Tp> struct __is_inplace_index_imp : false_type {};
+template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
+
+template <class _Tp>
+using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_IN_PLACE_H

diff  --git a/libcxx/include/__utility/integer_sequence.h b/libcxx/include/__utility/integer_sequence.h
new file mode 100644
index 0000000000000..963c4a9670707
--- /dev/null
+++ b/libcxx/include/__utility/integer_sequence.h
@@ -0,0 +1,83 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
+#define _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 11
+
+template<class _Tp, _Tp... _Ip>
+struct _LIBCPP_TEMPLATE_VIS 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_INLINE_VISIBILITY
+    constexpr
+    size_t
+    size() noexcept { return sizeof...(_Ip); }
+};
+
+template<size_t... _Ip>
+    using index_sequence = integer_sequence<size_t, _Ip...>;
+
+#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
+
+template <class _Tp, _Tp _Ep>
+using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = __make_integer_seq<integer_sequence, _Tp, _Ep>;
+
+#else
+
+template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG_TYPE  =
+  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
+
+template <class _Tp, _Tp _Ep>
+struct __make_integer_sequence_checked
+{
+    static_assert(is_integral<_Tp>::value,
+                  "std::make_integer_sequence can only be instantiated with an integral type" );
+    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
+    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
+    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
+    typedef _LIBCPP_NODEBUG_TYPE  __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
+};
+
+template <class _Tp, _Tp _Ep>
+using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
+
+#endif
+
+template<class _Tp, _Tp _Np>
+    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
+
+template<size_t _Np>
+    using make_index_sequence = make_integer_sequence<size_t, _Np>;
+
+template<class... _Tp>
+    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
+
+#endif // _LIBCPP_STD_VER > 11
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H

diff  --git a/libcxx/include/__utility/pair.h b/libcxx/include/__utility/pair.h
new file mode 100644
index 0000000000000..e0216f3402b82
--- /dev/null
+++ b/libcxx/include/__utility/pair.h
@@ -0,0 +1,585 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_PAIR_H
+#define _LIBCPP___UTILITY_PAIR_H
+
+#include <__config>
+#include <__functional/unwrap_ref.h>
+#include <__tuple>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/piecewise_construct.h>
+#include <cstddef>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+
+#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
+template <class, class>
+struct __non_trivially_copyable_base {
+  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+  __non_trivially_copyable_base() _NOEXCEPT {}
+  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
+};
+#endif
+
+template <class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS pair
+#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
+: private __non_trivially_copyable_base<_T1, _T2>
+#endif
+{
+    typedef _T1 first_type;
+    typedef _T2 second_type;
+
+    _T1 first;
+    _T2 second;
+
+#if !defined(_LIBCPP_CXX03_LANG)
+    pair(pair const&) = default;
+    pair(pair&&) = default;
+#else
+  // Use the implicitly declared copy constructor in C++03
+#endif
+
+#ifdef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    pair() : first(), second() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
+
+    template <class _U1, class _U2>
+    _LIBCPP_INLINE_VISIBILITY
+    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair& operator=(pair const& __p) {
+        first = __p.first;
+        second = __p.second;
+        return *this;
+    }
+#else
+    template <bool _Val>
+    using _EnableB _LIBCPP_NODEBUG_TYPE = typename enable_if<_Val, bool>::type;
+
+    struct _CheckArgs {
+      template <int&...>
+      static constexpr bool __enable_explicit_default() {
+          return is_default_constructible<_T1>::value
+              && is_default_constructible<_T2>::value
+              && !__enable_implicit_default<>();
+      }
+
+      template <int&...>
+      static constexpr bool __enable_implicit_default() {
+          return __is_implicitly_default_constructible<_T1>::value
+              && __is_implicitly_default_constructible<_T2>::value;
+      }
+
+      template <class _U1, class _U2>
+      static constexpr bool __enable_explicit() {
+          return is_constructible<first_type, _U1>::value
+              && is_constructible<second_type, _U2>::value
+              && (!is_convertible<_U1, first_type>::value
+                  || !is_convertible<_U2, second_type>::value);
+      }
+
+      template <class _U1, class _U2>
+      static constexpr bool __enable_implicit() {
+          return is_constructible<first_type, _U1>::value
+              && is_constructible<second_type, _U2>::value
+              && is_convertible<_U1, first_type>::value
+              && is_convertible<_U2, second_type>::value;
+      }
+    };
+
+    template <bool _MaybeEnable>
+    using _CheckArgsDep _LIBCPP_NODEBUG_TYPE = typename conditional<
+      _MaybeEnable, _CheckArgs, __check_tuple_constructor_fail>::type;
+
+    struct _CheckTupleLikeConstructor {
+        template <class _Tuple>
+        static constexpr bool __enable_implicit() {
+            return __tuple_convertible<_Tuple, pair>::value;
+        }
+
+        template <class _Tuple>
+        static constexpr bool __enable_explicit() {
+            return __tuple_constructible<_Tuple, pair>::value
+               && !__tuple_convertible<_Tuple, pair>::value;
+        }
+
+        template <class _Tuple>
+        static constexpr bool __enable_assign() {
+            return __tuple_assignable<_Tuple, pair>::value;
+        }
+    };
+
+    template <class _Tuple>
+    using _CheckTLC _LIBCPP_NODEBUG_TYPE = typename conditional<
+        __tuple_like_with_size<_Tuple, 2>::value
+            && !is_same<typename decay<_Tuple>::type, pair>::value,
+        _CheckTupleLikeConstructor,
+        __check_tuple_constructor_fail
+    >::type;
+
+    template<bool _Dummy = true, _EnableB<
+            _CheckArgsDep<_Dummy>::__enable_explicit_default()
+    > = false>
+    explicit _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
+                      is_nothrow_default_constructible<second_type>::value)
+        : first(), second() {}
+
+    template<bool _Dummy = true, _EnableB<
+            _CheckArgsDep<_Dummy>::__enable_implicit_default()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
+                      is_nothrow_default_constructible<second_type>::value)
+        : first(), second() {}
+
+    template <bool _Dummy = true, _EnableB<
+             _CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(_T1 const& __t1, _T2 const& __t2)
+        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
+                   is_nothrow_copy_constructible<second_type>::value)
+        : first(__t1), second(__t2) {}
+
+    template<bool _Dummy = true, _EnableB<
+            _CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(_T1 const& __t1, _T2 const& __t2)
+        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
+                   is_nothrow_copy_constructible<second_type>::value)
+        : first(__t1), second(__t2) {}
+
+    template<class _U1, class _U2, _EnableB<
+             _CheckArgs::template __enable_explicit<_U1, _U2>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(_U1&& __u1, _U2&& __u2)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
+                    is_nothrow_constructible<second_type, _U2>::value))
+        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
+
+    template<class _U1, class _U2, _EnableB<
+            _CheckArgs::template __enable_implicit<_U1, _U2>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(_U1&& __u1, _U2&& __u2)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
+                    is_nothrow_constructible<second_type, _U2>::value))
+        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
+
+    template<class _U1, class _U2, _EnableB<
+            _CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(pair<_U1, _U2> const& __p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
+                    is_nothrow_constructible<second_type, _U2 const&>::value))
+        : first(__p.first), second(__p.second) {}
+
+    template<class _U1, class _U2, _EnableB<
+            _CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(pair<_U1, _U2> const& __p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
+                    is_nothrow_constructible<second_type, _U2 const&>::value))
+        : first(__p.first), second(__p.second) {}
+
+    template<class _U1, class _U2, _EnableB<
+            _CheckArgs::template __enable_explicit<_U1, _U2>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(pair<_U1, _U2>&&__p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
+                    is_nothrow_constructible<second_type, _U2&&>::value))
+        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
+
+    template<class _U1, class _U2, _EnableB<
+            _CheckArgs::template __enable_implicit<_U1, _U2>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(pair<_U1, _U2>&& __p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
+                    is_nothrow_constructible<second_type, _U2&&>::value))
+        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
+
+    template<class _Tuple, _EnableB<
+            _CheckTLC<_Tuple>::template __enable_explicit<_Tuple>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(_Tuple&& __p)
+        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
+          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
+
+    template<class _Tuple, _EnableB<
+            _CheckTLC<_Tuple>::template __enable_implicit<_Tuple>()
+    > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(_Tuple&& __p)
+        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
+          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
+
+    template <class... _Args1, class... _Args2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair(piecewise_construct_t __pc,
+         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _Args1...>::value &&
+                    is_nothrow_constructible<second_type, _Args2...>::value))
+        : pair(__pc, __first_args, __second_args,
+                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
+                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair& operator=(typename conditional<
+                        is_copy_assignable<first_type>::value &&
+                        is_copy_assignable<second_type>::value,
+                    pair, __nat>::type const& __p)
+        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
+                   is_nothrow_copy_assignable<second_type>::value)
+    {
+        first = __p.first;
+        second = __p.second;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair& operator=(typename conditional<
+                        is_move_assignable<first_type>::value &&
+                        is_move_assignable<second_type>::value,
+                    pair, __nat>::type&& __p)
+        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
+                   is_nothrow_move_assignable<second_type>::value)
+    {
+        first = _VSTD::forward<first_type>(__p.first);
+        second = _VSTD::forward<second_type>(__p.second);
+        return *this;
+    }
+
+    template <class _Tuple, _EnableB<
+            _CheckTLC<_Tuple>::template __enable_assign<_Tuple>()
+     > = false>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair& operator=(_Tuple&& __p) {
+        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
+        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
+        return *this;
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void
+    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
+                               __is_nothrow_swappable<second_type>::value)
+    {
+        using _VSTD::swap;
+        swap(first,  __p.first);
+        swap(second, __p.second);
+    }
+private:
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair(piecewise_construct_t,
+         tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
+         __tuple_indices<_I1...>, __tuple_indices<_I2...>);
+#endif
+};
+
+#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
+template<class _T1, class _T2>
+pair(_T1, _T2) -> pair<_T1, _T2>;
+#endif // _LIBCPP_HAS_NO_DEDUCTION_GUIDES
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return __x.first == __y.first && __x.second == __y.second;
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return __y < __x;
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if
+<
+    __is_swappable<_T1>::value &&
+    __is_swappable<_T2>::value,
+    void
+>::type
+swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
+                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
+                                 __is_nothrow_swappable<_T2>::value))
+{
+    __x.swap(__y);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
+make_pair(_T1&& __t1, _T2&& __t2)
+{
+    return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
+               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
+}
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_T1,_T2>
+make_pair(_T1 __x, _T2 __y)
+{
+    return pair<_T1, _T2>(__x, __y);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _T1, class _T2>
+  struct _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
+    : public integral_constant<size_t, 2> {};
+
+template <size_t _Ip, class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
+{
+    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
+};
+
+template <class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
+{
+    typedef _LIBCPP_NODEBUG_TYPE _T1 type;
+};
+
+template <class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
+{
+    typedef _LIBCPP_NODEBUG_TYPE _T2 type;
+};
+
+template <size_t _Ip> struct __get_pair;
+
+template <>
+struct __get_pair<0>
+{
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T1&
+    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T1&
+    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T1&&
+    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T1&&
+    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
+#endif // _LIBCPP_CXX03_LANG
+};
+
+template <>
+struct __get_pair<1>
+{
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T2&
+    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T2&
+    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T2&&
+    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T2&&
+    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
+#endif // _LIBCPP_CXX03_LANG
+};
+
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, pair<_T1, _T2> >::type&
+get(pair<_T1, _T2>& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(__p);
+}
+
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
+get(const pair<_T1, _T2>& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(__p);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
+get(pair<_T1, _T2>&& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(_VSTD::move(__p));
+}
+
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
+get(const pair<_T1, _T2>&& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(_VSTD::move(__p));
+}
+#endif // _LIBCPP_CXX03_LANG
+
+#if _LIBCPP_STD_VER > 11
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(_VSTD::move(__p));
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(_VSTD::move(__p));
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(_VSTD::move(__p));
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(_VSTD::move(__p));
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_PAIR_H

diff  --git a/libcxx/include/__utility/piecewise_construct.h b/libcxx/include/__utility/piecewise_construct.h
new file mode 100644
index 0000000000000..8bef01c9f269d
--- /dev/null
+++ b/libcxx/include/__utility/piecewise_construct.h
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_PIECEWISE_CONSTRUCT_H
+#define _LIBCPP___UTILITY_PIECEWISE_CONSTRUCT_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { explicit piecewise_construct_t() = default; };
+#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
+extern _LIBCPP_EXPORTED_FROM_ABI const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
+#else
+/* _LIBCPP_INLINE_VAR */ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_PIECEWISE_CONSTRUCT_H

diff  --git a/libcxx/include/__utility/rel_ops.h b/libcxx/include/__utility/rel_ops.h
new file mode 100644
index 0000000000000..b900da80f48d8
--- /dev/null
+++ b/libcxx/include/__utility/rel_ops.h
@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_REL_OPS_H
+#define _LIBCPP___UTILITY_REL_OPS_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace rel_ops
+{
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const _Tp& __x, const _Tp& __y)
+{
+    return !(__x == __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const _Tp& __x, const _Tp& __y)
+{
+    return __y < __x;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const _Tp& __x, const _Tp& __y)
+{
+    return !(__y < __x);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const _Tp& __x, const _Tp& __y)
+{
+    return !(__x < __y);
+}
+
+}  // rel_ops
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_REL_OPS_H

diff  --git a/libcxx/include/deque b/libcxx/include/deque
index 1f23ef0c78696..aff93deb10107 100644
--- a/libcxx/include/deque
+++ b/libcxx/include/deque
@@ -168,6 +168,7 @@ template <class T, class Allocator, class Predicate>
 #include <compare>
 #include <initializer_list>
 #include <iterator>
+#include <limits>
 #include <stdexcept>
 #include <type_traits>
 #include <version>

diff  --git a/libcxx/include/functional b/libcxx/include/functional
index 249c0dc02be6b..2b2dcd26ce46f 100644
--- a/libcxx/include/functional
+++ b/libcxx/include/functional
@@ -490,7 +490,10 @@ POLICY:  For non-variadic implementations, the number of arguments is limited
 #include <__config>
 #include <__debug>
 #include <__functional_base>
+#include <__functional/hash.h>
 #include <__functional/search.h>
+#include <__functional/unary_function.h>
+#include <__functional/unwrap_ref.h>
 #include <__utility/forward.h>
 #include <concepts>
 #include <exception>

diff  --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index c5f9f43b87068..48573377bb7b0 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -408,7 +408,10 @@ module std [system] {
     header "functional"
     export *
     module __functional {
-      module search { header "__functional/search.h" }
+      module hash           { header "__functional/hash.h"           }
+      module search         { header "__functional/search.h"         }
+      module unary_function { header "__functional/unary_function.h" }
+      module unwrap_ref     { header "__functional/unwrap_ref.h"     }
     }
   }
   module future {
@@ -640,6 +643,7 @@ module std [system] {
   }
   module type_traits {
     header "type_traits"
+    export functional.__functional.unwrap_ref
     export *
   }
   module typeindex {
@@ -666,12 +670,20 @@ module std [system] {
     export *
 
     module __utility {
-      module __decay_copy  { header "__utility/__decay_copy.h"  }
-      module declval       { header "__utility/declval.h"       }
-      module forward       { header "__utility/forward.h"       }
-      module move          { header "__utility/move.h"          }
-      module swap          { header "__utility/swap.h"          }
-      module to_underlying { header "__utility/to_underlying.h" }
+      module __decay_copy        { header "__utility/__decay_copy.h"        }
+      module as_const            { header "__utility/as_const.h"            }
+      module cmp                 { header "__utility/cmp.h"                 }
+      module declval             { header "__utility/declval.h"             }
+      module exchange            { header "__utility/exchange.h"            }
+      module forward             { header "__utility/forward.h"             }
+      module in_place            { header "__utility/in_place.h"            }
+      module integer_sequence    { header "__utility/integer_sequence.h"    }
+      module move                { header "__utility/move.h"                }
+      module pair                { header "__utility/pair.h"                }
+      module piecewise_construct { header "__utility/piecewise_construct.h" }
+      module rel_ops             { header "__utility/rel_ops.h"             }
+      module swap                { header "__utility/swap.h"                }
+      module to_underlying       { header "__utility/to_underlying.h"       }
     }
   }
   module valarray {

diff  --git a/libcxx/include/span b/libcxx/include/span
index 1d4335b3ad579..80c550daa3a5d 100644
--- a/libcxx/include/span
+++ b/libcxx/include/span
@@ -134,6 +134,7 @@ template<class Container>
 #include <array>        // for array
 #include <cstddef>      // for byte
 #include <iterator>     // for iterators
+#include <limits>
 #include <type_traits>  // for remove_cv, etc
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

diff  --git a/libcxx/include/tuple b/libcxx/include/tuple
index 3a4b0dfec5f00..42e05b988faa8 100644
--- a/libcxx/include/tuple
+++ b/libcxx/include/tuple
@@ -151,6 +151,7 @@ template <class... Types>
 
 #include <__config>
 #include <__functional_base>
+#include <__functional/unwrap_ref.h>
 #include <__utility/forward.h>
 #include <__utility/move.h>
 #include <__tuple>

diff  --git a/libcxx/include/utility b/libcxx/include/utility
index 49e7b3e85c671..83ad035c9f90a 100644
--- a/libcxx/include/utility
+++ b/libcxx/include/utility
@@ -210,1675 +210,21 @@ template <class T>
 #include <__config>
 #include <__debug>
 #include <__tuple>
+#include <__utility/as_const.h>
+#include <__utility/cmp.h>
 #include <__utility/declval.h>
+#include <__utility/exchange.h>
 #include <__utility/forward.h>
+#include <__utility/in_place.h>
+#include <__utility/integer_sequence.h>
 #include <__utility/move.h>
+#include <__utility/pair.h>
+#include <__utility/piecewise_construct.h>
+#include <__utility/rel_ops.h>
 #include <__utility/swap.h>
 #include <__utility/to_underlying.h>
 #include <compare>
-#include <cstddef>
-#include <cstdint>
-#include <cstring>
 #include <initializer_list>
-#include <limits>
-#include <type_traits>
 #include <version>
 
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#pragma GCC system_header
-#endif
-
-_LIBCPP_PUSH_MACROS
-#include <__undef_macros>
-
-_LIBCPP_BEGIN_NAMESPACE_STD
-
-namespace rel_ops
-{
-
-template<class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-operator!=(const _Tp& __x, const _Tp& __y)
-{
-    return !(__x == __y);
-}
-
-template<class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-operator> (const _Tp& __x, const _Tp& __y)
-{
-    return __y < __x;
-}
-
-template<class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-operator<=(const _Tp& __x, const _Tp& __y)
-{
-    return !(__y < __x);
-}
-
-template<class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY
-bool
-operator>=(const _Tp& __x, const _Tp& __y)
-{
-    return !(__x < __y);
-}
-
-}  // rel_ops
-
-#if _LIBCPP_STD_VER > 14
-template <class _Tp>
-_LIBCPP_NODISCARD_EXT constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
-
-template <class _Tp>
-void as_const(const _Tp&&) = delete;
-#endif
-
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
-template<class _Tp, class... _Up>
-struct _IsSameAsAny : _Or<_IsSame<_Tp, _Up>...> {};
-
-template<class _Tp>
-concept __is_safe_integral_cmp = is_integral_v<_Tp> &&
-                      !_IsSameAsAny<_Tp, bool, char,
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
-                                    char8_t,
-#endif
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-                                    char16_t, char32_t,
-#endif
-                                    wchar_t>::value;
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool cmp_equal(_Tp __t, _Up __u) noexcept
-{
-  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
-    return __t == __u;
-  else if constexpr (is_signed_v<_Tp>)
-    return __t < 0 ? false : make_unsigned_t<_Tp>(__t) == __u;
-  else
-    return __u < 0 ? false : __t == make_unsigned_t<_Up>(__u);
-}
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool cmp_not_equal(_Tp __t, _Up __u) noexcept
-{
-  return !_VSTD::cmp_equal(__t, __u);
-}
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool cmp_less(_Tp __t, _Up __u) noexcept
-{
-  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
-    return __t < __u;
-  else if constexpr (is_signed_v<_Tp>)
-    return __t < 0 ? true : make_unsigned_t<_Tp>(__t) < __u;
-  else
-    return __u < 0 ? false : __t < make_unsigned_t<_Up>(__u);
-}
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool cmp_greater(_Tp __t, _Up __u) noexcept
-{
-  return _VSTD::cmp_less(__u, __t);
-}
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool cmp_less_equal(_Tp __t, _Up __u) noexcept
-{
-  return !_VSTD::cmp_greater(__t, __u);
-}
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool cmp_greater_equal(_Tp __t, _Up __u) noexcept
-{
-  return !_VSTD::cmp_less(__t, __u);
-}
-
-template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
-_LIBCPP_INLINE_VISIBILITY constexpr
-bool in_range(_Up __u) noexcept
-{
-  return _VSTD::cmp_less_equal(__u, numeric_limits<_Tp>::max()) &&
-         _VSTD::cmp_greater_equal(__u, numeric_limits<_Tp>::min());
-}
-#endif
-
-struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { explicit piecewise_construct_t() = default; };
-#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
-extern _LIBCPP_EXPORTED_FROM_ABI const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
-#else
-/* _LIBCPP_INLINE_VAR */ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
-#endif
-
-#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
-template <class, class>
-struct __non_trivially_copyable_base {
-  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-  __non_trivially_copyable_base() _NOEXCEPT {}
-  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
-  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
-};
-#endif
-
-template <class _T1, class _T2>
-struct _LIBCPP_TEMPLATE_VIS pair
-#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
-: private __non_trivially_copyable_base<_T1, _T2>
-#endif
-{
-    typedef _T1 first_type;
-    typedef _T2 second_type;
-
-    _T1 first;
-    _T2 second;
-
-#if !defined(_LIBCPP_CXX03_LANG)
-    pair(pair const&) = default;
-    pair(pair&&) = default;
-#else
-  // Use the implicitly declared copy constructor in C++03
-#endif
-
-#ifdef _LIBCPP_CXX03_LANG
-    _LIBCPP_INLINE_VISIBILITY
-    pair() : first(), second() {}
-
-    _LIBCPP_INLINE_VISIBILITY
-    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
-
-    template <class _U1, class _U2>
-    _LIBCPP_INLINE_VISIBILITY
-    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
-
-    _LIBCPP_INLINE_VISIBILITY
-    pair& operator=(pair const& __p) {
-        first = __p.first;
-        second = __p.second;
-        return *this;
-    }
-#else
-    template <bool _Val>
-    using _EnableB _LIBCPP_NODEBUG_TYPE = typename enable_if<_Val, bool>::type;
-
-    struct _CheckArgs {
-      template <int&...>
-      static constexpr bool __enable_explicit_default() {
-          return is_default_constructible<_T1>::value
-              && is_default_constructible<_T2>::value
-              && !__enable_implicit_default<>();
-      }
-
-      template <int&...>
-      static constexpr bool __enable_implicit_default() {
-          return __is_implicitly_default_constructible<_T1>::value
-              && __is_implicitly_default_constructible<_T2>::value;
-      }
-
-      template <class _U1, class _U2>
-      static constexpr bool __enable_explicit() {
-          return is_constructible<first_type, _U1>::value
-              && is_constructible<second_type, _U2>::value
-              && (!is_convertible<_U1, first_type>::value
-                  || !is_convertible<_U2, second_type>::value);
-      }
-
-      template <class _U1, class _U2>
-      static constexpr bool __enable_implicit() {
-          return is_constructible<first_type, _U1>::value
-              && is_constructible<second_type, _U2>::value
-              && is_convertible<_U1, first_type>::value
-              && is_convertible<_U2, second_type>::value;
-      }
-    };
-
-    template <bool _MaybeEnable>
-    using _CheckArgsDep _LIBCPP_NODEBUG_TYPE = typename conditional<
-      _MaybeEnable, _CheckArgs, __check_tuple_constructor_fail>::type;
-
-    struct _CheckTupleLikeConstructor {
-        template <class _Tuple>
-        static constexpr bool __enable_implicit() {
-            return __tuple_convertible<_Tuple, pair>::value;
-        }
-
-        template <class _Tuple>
-        static constexpr bool __enable_explicit() {
-            return __tuple_constructible<_Tuple, pair>::value
-               && !__tuple_convertible<_Tuple, pair>::value;
-        }
-
-        template <class _Tuple>
-        static constexpr bool __enable_assign() {
-            return __tuple_assignable<_Tuple, pair>::value;
-        }
-    };
-
-    template <class _Tuple>
-    using _CheckTLC _LIBCPP_NODEBUG_TYPE = typename conditional<
-        __tuple_like_with_size<_Tuple, 2>::value
-            && !is_same<typename decay<_Tuple>::type, pair>::value,
-        _CheckTupleLikeConstructor,
-        __check_tuple_constructor_fail
-    >::type;
-
-    template<bool _Dummy = true, _EnableB<
-            _CheckArgsDep<_Dummy>::__enable_explicit_default()
-    > = false>
-    explicit _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
-    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
-                      is_nothrow_default_constructible<second_type>::value)
-        : first(), second() {}
-
-    template<bool _Dummy = true, _EnableB<
-            _CheckArgsDep<_Dummy>::__enable_implicit_default()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
-    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
-                      is_nothrow_default_constructible<second_type>::value)
-        : first(), second() {}
-
-    template <bool _Dummy = true, _EnableB<
-             _CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    explicit pair(_T1 const& __t1, _T2 const& __t2)
-        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
-                   is_nothrow_copy_constructible<second_type>::value)
-        : first(__t1), second(__t2) {}
-
-    template<bool _Dummy = true, _EnableB<
-            _CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    pair(_T1 const& __t1, _T2 const& __t2)
-        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
-                   is_nothrow_copy_constructible<second_type>::value)
-        : first(__t1), second(__t2) {}
-
-    template<class _U1, class _U2, _EnableB<
-             _CheckArgs::template __enable_explicit<_U1, _U2>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    explicit pair(_U1&& __u1, _U2&& __u2)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
-                    is_nothrow_constructible<second_type, _U2>::value))
-        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
-
-    template<class _U1, class _U2, _EnableB<
-            _CheckArgs::template __enable_implicit<_U1, _U2>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    pair(_U1&& __u1, _U2&& __u2)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
-                    is_nothrow_constructible<second_type, _U2>::value))
-        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
-
-    template<class _U1, class _U2, _EnableB<
-            _CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    explicit pair(pair<_U1, _U2> const& __p)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
-                    is_nothrow_constructible<second_type, _U2 const&>::value))
-        : first(__p.first), second(__p.second) {}
-
-    template<class _U1, class _U2, _EnableB<
-            _CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    pair(pair<_U1, _U2> const& __p)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
-                    is_nothrow_constructible<second_type, _U2 const&>::value))
-        : first(__p.first), second(__p.second) {}
-
-    template<class _U1, class _U2, _EnableB<
-            _CheckArgs::template __enable_explicit<_U1, _U2>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    explicit pair(pair<_U1, _U2>&&__p)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
-                    is_nothrow_constructible<second_type, _U2&&>::value))
-        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
-
-    template<class _U1, class _U2, _EnableB<
-            _CheckArgs::template __enable_implicit<_U1, _U2>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    pair(pair<_U1, _U2>&& __p)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
-                    is_nothrow_constructible<second_type, _U2&&>::value))
-        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
-
-    template<class _Tuple, _EnableB<
-            _CheckTLC<_Tuple>::template __enable_explicit<_Tuple>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    explicit pair(_Tuple&& __p)
-        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
-          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
-
-    template<class _Tuple, _EnableB<
-            _CheckTLC<_Tuple>::template __enable_implicit<_Tuple>()
-    > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    pair(_Tuple&& __p)
-        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
-          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
-
-    template <class... _Args1, class... _Args2>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-    pair(piecewise_construct_t __pc,
-         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
-        _NOEXCEPT_((is_nothrow_constructible<first_type, _Args1...>::value &&
-                    is_nothrow_constructible<second_type, _Args2...>::value))
-        : pair(__pc, __first_args, __second_args,
-                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
-                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
-
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-    pair& operator=(typename conditional<
-                        is_copy_assignable<first_type>::value &&
-                        is_copy_assignable<second_type>::value,
-                    pair, __nat>::type const& __p)
-        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
-                   is_nothrow_copy_assignable<second_type>::value)
-    {
-        first = __p.first;
-        second = __p.second;
-        return *this;
-    }
-
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-    pair& operator=(typename conditional<
-                        is_move_assignable<first_type>::value &&
-                        is_move_assignable<second_type>::value,
-                    pair, __nat>::type&& __p)
-        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
-                   is_nothrow_move_assignable<second_type>::value)
-    {
-        first = _VSTD::forward<first_type>(__p.first);
-        second = _VSTD::forward<second_type>(__p.second);
-        return *this;
-    }
-
-    template <class _Tuple, _EnableB<
-            _CheckTLC<_Tuple>::template __enable_assign<_Tuple>()
-     > = false>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-    pair& operator=(_Tuple&& __p) {
-        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
-        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
-        return *this;
-    }
-#endif
-
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-    void
-    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
-                               __is_nothrow_swappable<second_type>::value)
-    {
-        using _VSTD::swap;
-        swap(first,  __p.first);
-        swap(second, __p.second);
-    }
-private:
-
-#ifndef _LIBCPP_CXX03_LANG
-    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-    pair(piecewise_construct_t,
-         tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
-         __tuple_indices<_I1...>, __tuple_indices<_I2...>);
-#endif
-};
-
-#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
-template<class _T1, class _T2>
-pair(_T1, _T2) -> pair<_T1, _T2>;
-#endif // _LIBCPP_HAS_NO_DEDUCTION_GUIDES
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-bool
-operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
-{
-    return __x.first == __y.first && __x.second == __y.second;
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-bool
-operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
-{
-    return !(__x == __y);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-bool
-operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
-{
-    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-bool
-operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
-{
-    return __y < __x;
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-bool
-operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
-{
-    return !(__x < __y);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-bool
-operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
-{
-    return !(__y < __x);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-typename enable_if
-<
-    __is_swappable<_T1>::value &&
-    __is_swappable<_T2>::value,
-    void
->::type
-swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
-                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
-                                 __is_nothrow_swappable<_T2>::value))
-{
-    __x.swap(__y);
-}
-
-template <class _Tp>
-struct __unwrap_reference { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
-
-template <class _Tp>
-struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
-
-#if _LIBCPP_STD_VER > 17
-template <class _Tp>
-struct unwrap_reference : __unwrap_reference<_Tp> { };
-
-template <class _Tp>
-struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
-#endif // > C++17
-
-template <class _Tp>
-struct __unwrap_ref_decay
-#if _LIBCPP_STD_VER > 17
-    : unwrap_ref_decay<_Tp>
-#else
-    : __unwrap_reference<typename decay<_Tp>::type>
-#endif
-{ };
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
-make_pair(_T1&& __t1, _T2&& __t2)
-{
-    return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
-               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
-}
-
-#else  // _LIBCPP_CXX03_LANG
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-pair<_T1,_T2>
-make_pair(_T1 __x, _T2 __y)
-{
-    return pair<_T1, _T2>(__x, __y);
-}
-
-#endif // _LIBCPP_CXX03_LANG
-
-template <class _T1, class _T2>
-  struct _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
-    : public integral_constant<size_t, 2> {};
-
-template <size_t _Ip, class _T1, class _T2>
-struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
-{
-    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
-};
-
-template <class _T1, class _T2>
-struct _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
-{
-    typedef _LIBCPP_NODEBUG_TYPE _T1 type;
-};
-
-template <class _T1, class _T2>
-struct _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
-{
-    typedef _LIBCPP_NODEBUG_TYPE _T2 type;
-};
-
-template <size_t _Ip> struct __get_pair;
-
-template <>
-struct __get_pair<0>
-{
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    _T1&
-    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
-
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    const _T1&
-    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
-
-#ifndef _LIBCPP_CXX03_LANG
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    _T1&&
-    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
-
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    const _T1&&
-    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
-#endif // _LIBCPP_CXX03_LANG
-};
-
-template <>
-struct __get_pair<1>
-{
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    _T2&
-    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
-
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    const _T2&
-    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
-
-#ifndef _LIBCPP_CXX03_LANG
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    _T2&&
-    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
-
-    template <class _T1, class _T2>
-    static
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-    const _T2&&
-    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
-#endif // _LIBCPP_CXX03_LANG
-};
-
-template <size_t _Ip, class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-typename tuple_element<_Ip, pair<_T1, _T2> >::type&
-get(pair<_T1, _T2>& __p) _NOEXCEPT
-{
-    return __get_pair<_Ip>::get(__p);
-}
-
-template <size_t _Ip, class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
-get(const pair<_T1, _T2>& __p) _NOEXCEPT
-{
-    return __get_pair<_Ip>::get(__p);
-}
-
-#ifndef _LIBCPP_CXX03_LANG
-template <size_t _Ip, class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
-get(pair<_T1, _T2>&& __p) _NOEXCEPT
-{
-    return __get_pair<_Ip>::get(_VSTD::move(__p));
-}
-
-template <size_t _Ip, class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
-get(const pair<_T1, _T2>&& __p) _NOEXCEPT
-{
-    return __get_pair<_Ip>::get(_VSTD::move(__p));
-}
-#endif // _LIBCPP_CXX03_LANG
-
-#if _LIBCPP_STD_VER > 11
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
-{
-    return __get_pair<0>::get(__p);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
-{
-    return __get_pair<0>::get(__p);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
-{
-    return __get_pair<0>::get(_VSTD::move(__p));
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
-{
-    return __get_pair<0>::get(_VSTD::move(__p));
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
-{
-    return __get_pair<1>::get(__p);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
-{
-    return __get_pair<1>::get(__p);
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
-{
-    return __get_pair<1>::get(_VSTD::move(__p));
-}
-
-template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
-constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
-{
-    return __get_pair<1>::get(_VSTD::move(__p));
-}
-
-#endif
-
-#if _LIBCPP_STD_VER > 11
-
-template<class _Tp, _Tp... _Ip>
-struct _LIBCPP_TEMPLATE_VIS 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_INLINE_VISIBILITY
-    constexpr
-    size_t
-    size() noexcept { return sizeof...(_Ip); }
-};
-
-template<size_t... _Ip>
-    using index_sequence = integer_sequence<size_t, _Ip...>;
-
-#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
-
-template <class _Tp, _Tp _Ep>
-using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = __make_integer_seq<integer_sequence, _Tp, _Ep>;
-
-#else
-
-template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG_TYPE  =
-  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
-
-template <class _Tp, _Tp _Ep>
-struct __make_integer_sequence_checked
-{
-    static_assert(is_integral<_Tp>::value,
-                  "std::make_integer_sequence can only be instantiated with an integral type" );
-    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
-    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
-    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
-    typedef _LIBCPP_NODEBUG_TYPE  __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
-};
-
-template <class _Tp, _Tp _Ep>
-using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
-
-#endif
-
-template<class _Tp, _Tp _Np>
-    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
-
-template<size_t _Np>
-    using make_index_sequence = make_integer_sequence<size_t, _Np>;
-
-template<class... _Tp>
-    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
-
-#endif // _LIBCPP_STD_VER > 11
-
-#if _LIBCPP_STD_VER > 11
-template<class _T1, class _T2 = _T1>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-_T1 exchange(_T1& __obj, _T2 && __new_value)
-{
-    _T1 __old_value = _VSTD::move(__obj);
-    __obj = _VSTD::forward<_T2>(__new_value);
-    return __old_value;
-}
-#endif // _LIBCPP_STD_VER > 11
-
-#if _LIBCPP_STD_VER > 14
-
-struct _LIBCPP_TYPE_VIS in_place_t {
-    explicit in_place_t() = default;
-};
-_LIBCPP_INLINE_VAR constexpr in_place_t in_place{};
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
-    explicit in_place_type_t() = default;
-};
-template <class _Tp>
-_LIBCPP_INLINE_VAR constexpr in_place_type_t<_Tp> in_place_type{};
-
-template <size_t _Idx>
-struct _LIBCPP_TEMPLATE_VIS in_place_index_t {
-    explicit in_place_index_t() = default;
-};
-template <size_t _Idx>
-_LIBCPP_INLINE_VAR constexpr in_place_index_t<_Idx> in_place_index{};
-
-template <class _Tp> struct __is_inplace_type_imp : false_type {};
-template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
-
-template <class _Tp>
-using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
-
-template <class _Tp> struct __is_inplace_index_imp : false_type {};
-template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
-
-template <class _Tp>
-using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
-
-#endif // _LIBCPP_STD_VER > 14
-
-template <class _Arg, class _Result>
-struct _LIBCPP_TEMPLATE_VIS unary_function
-{
-    typedef _Arg    argument_type;
-    typedef _Result result_type;
-};
-
-template <class _Size>
-inline _LIBCPP_INLINE_VISIBILITY
-_Size
-__loadword(const void* __p)
-{
-    _Size __r;
-    _VSTD::memcpy(&__r, __p, sizeof(__r));
-    return __r;
-}
-
-// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
-// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
-// multiplication, which can be very slow on 32-bit systems.
-template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
-struct __murmur2_or_cityhash;
-
-template <class _Size>
-struct __murmur2_or_cityhash<_Size, 32>
-{
-    inline _Size operator()(const void* __key, _Size __len)
-         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
-};
-
-// murmur2
-template <class _Size>
-_Size
-__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
-{
-    const _Size __m = 0x5bd1e995;
-    const _Size __r = 24;
-    _Size __h = __len;
-    const unsigned char* __data = static_cast<const unsigned char*>(__key);
-    for (; __len >= 4; __data += 4, __len -= 4)
-    {
-        _Size __k = __loadword<_Size>(__data);
-        __k *= __m;
-        __k ^= __k >> __r;
-        __k *= __m;
-        __h *= __m;
-        __h ^= __k;
-    }
-    switch (__len)
-    {
-    case 3:
-        __h ^= __data[2] << 16;
-        _LIBCPP_FALLTHROUGH();
-    case 2:
-        __h ^= __data[1] << 8;
-        _LIBCPP_FALLTHROUGH();
-    case 1:
-        __h ^= __data[0];
-        __h *= __m;
-    }
-    __h ^= __h >> 13;
-    __h *= __m;
-    __h ^= __h >> 15;
-    return __h;
-}
-
-template <class _Size>
-struct __murmur2_or_cityhash<_Size, 64>
-{
-    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
-
- private:
-  // Some primes between 2^63 and 2^64.
-  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
-  static const _Size __k1 = 0xb492b66fbe98f273ULL;
-  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
-  static const _Size __k3 = 0xc949d7c7509e6557ULL;
-
-  static _Size __rotate(_Size __val, int __shift) {
-    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
-  }
-
-  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
-    return (__val >> __shift) | (__val << (64 - __shift));
-  }
-
-  static _Size __shift_mix(_Size __val) {
-    return __val ^ (__val >> 47);
-  }
-
-  static _Size __hash_len_16(_Size __u, _Size __v)
-     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-  {
-    const _Size __mul = 0x9ddfea08eb382d69ULL;
-    _Size __a = (__u ^ __v) * __mul;
-    __a ^= (__a >> 47);
-    _Size __b = (__v ^ __a) * __mul;
-    __b ^= (__b >> 47);
-    __b *= __mul;
-    return __b;
-  }
-
-  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
-     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-  {
-    if (__len > 8) {
-      const _Size __a = __loadword<_Size>(__s);
-      const _Size __b = __loadword<_Size>(__s + __len - 8);
-      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
-    }
-    if (__len >= 4) {
-      const uint32_t __a = __loadword<uint32_t>(__s);
-      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
-      return __hash_len_16(__len + (__a << 3), __b);
-    }
-    if (__len > 0) {
-      const unsigned char __a = __s[0];
-      const unsigned char __b = __s[__len >> 1];
-      const unsigned char __c = __s[__len - 1];
-      const uint32_t __y = static_cast<uint32_t>(__a) +
-                           (static_cast<uint32_t>(__b) << 8);
-      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
-      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
-    }
-    return __k2;
-  }
-
-  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
-     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-  {
-    const _Size __a = __loadword<_Size>(__s) * __k1;
-    const _Size __b = __loadword<_Size>(__s + 8);
-    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
-    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
-    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
-                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
-  }
-
-  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
-  // Callers do best to use "random-looking" values for a and b.
-  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
-      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
-        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-  {
-    __a += __w;
-    __b = __rotate(__b + __a + __z, 21);
-    const _Size __c = __a;
-    __a += __x;
-    __a += __y;
-    __b += __rotate(__a, 44);
-    return pair<_Size, _Size>(__a + __z, __b + __c);
-  }
-
-  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
-  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
-      const char* __s, _Size __a, _Size __b)
-    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-  {
-    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
-                                         __loadword<_Size>(__s + 8),
-                                         __loadword<_Size>(__s + 16),
-                                         __loadword<_Size>(__s + 24),
-                                         __a,
-                                         __b);
-  }
-
-  // Return an 8-byte hash for 33 to 64 bytes.
-  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
-    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
-  {
-    _Size __z = __loadword<_Size>(__s + 24);
-    _Size __a = __loadword<_Size>(__s) +
-                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
-    _Size __b = __rotate(__a + __z, 52);
-    _Size __c = __rotate(__a, 37);
-    __a += __loadword<_Size>(__s + 8);
-    __c += __rotate(__a, 7);
-    __a += __loadword<_Size>(__s + 16);
-    _Size __vf = __a + __z;
-    _Size __vs = __b + __rotate(__a, 31) + __c;
-    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
-    __z += __loadword<_Size>(__s + __len - 8);
-    __b = __rotate(__a + __z, 52);
-    __c = __rotate(__a, 37);
-    __a += __loadword<_Size>(__s + __len - 24);
-    __c += __rotate(__a, 7);
-    __a += __loadword<_Size>(__s + __len - 16);
-    _Size __wf = __a + __z;
-    _Size __ws = __b + __rotate(__a, 31) + __c;
-    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
-    return __shift_mix(__r * __k0 + __vs) * __k2;
-  }
-};
-
-// cityhash64
-template <class _Size>
-_Size
-__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
-{
-  const char* __s = static_cast<const char*>(__key);
-  if (__len <= 32) {
-    if (__len <= 16) {
-      return __hash_len_0_to_16(__s, __len);
-    } else {
-      return __hash_len_17_to_32(__s, __len);
-    }
-  } else if (__len <= 64) {
-    return __hash_len_33_to_64(__s, __len);
-  }
-
-  // For strings over 64 bytes we hash the end first, and then as we
-  // loop we keep 56 bytes of state: v, w, x, y, and z.
-  _Size __x = __loadword<_Size>(__s + __len - 40);
-  _Size __y = __loadword<_Size>(__s + __len - 16) +
-              __loadword<_Size>(__s + __len - 56);
-  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
-                          __loadword<_Size>(__s + __len - 24));
-  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
-  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
-  __x = __x * __k1 + __loadword<_Size>(__s);
-
-  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
-  __len = (__len - 1) & ~static_cast<_Size>(63);
-  do {
-    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
-    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
-    __x ^= __w.second;
-    __y += __v.first + __loadword<_Size>(__s + 40);
-    __z = __rotate(__z + __w.first, 33) * __k1;
-    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
-    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
-                                        __y + __loadword<_Size>(__s + 16));
-    _VSTD::swap(__z, __x);
-    __s += 64;
-    __len -= 64;
-  } while (__len != 0);
-  return __hash_len_16(
-      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
-      __hash_len_16(__v.second, __w.second) + __x);
-}
-
-template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
-struct __scalar_hash;
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <class _Tp>
-struct __scalar_hash<_Tp, 0>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp __v) const _NOEXCEPT
-    {
-        union
-        {
-            _Tp    __t;
-            size_t __a;
-        } __u;
-        __u.__a = 0;
-        __u.__t = __v;
-        return __u.__a;
-    }
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <class _Tp>
-struct __scalar_hash<_Tp, 1>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp __v) const _NOEXCEPT
-    {
-        union
-        {
-            _Tp    __t;
-            size_t __a;
-        } __u;
-        __u.__t = __v;
-        return __u.__a;
-    }
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <class _Tp>
-struct __scalar_hash<_Tp, 2>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp __v) const _NOEXCEPT
-    {
-        union
-        {
-            _Tp __t;
-            struct
-            {
-                size_t __a;
-                size_t __b;
-            } __s;
-        } __u;
-        __u.__t = __v;
-        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
-    }
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <class _Tp>
-struct __scalar_hash<_Tp, 3>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp __v) const _NOEXCEPT
-    {
-        union
-        {
-            _Tp __t;
-            struct
-            {
-                size_t __a;
-                size_t __b;
-                size_t __c;
-            } __s;
-        } __u;
-        __u.__t = __v;
-        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
-    }
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <class _Tp>
-struct __scalar_hash<_Tp, 4>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp __v) const _NOEXCEPT
-    {
-        union
-        {
-            _Tp __t;
-            struct
-            {
-                size_t __a;
-                size_t __b;
-                size_t __c;
-                size_t __d;
-            } __s;
-        } __u;
-        __u.__t = __v;
-        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
-    }
-};
-
-struct _PairT {
-  size_t first;
-  size_t second;
-};
-
-_LIBCPP_INLINE_VISIBILITY
-inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
-    typedef __scalar_hash<_PairT> _HashT;
-    const _PairT __p = {__lhs, __rhs};
-    return _HashT()(__p);
-}
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template<class _Tp>
-struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp*, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp* __v) const _NOEXCEPT
-    {
-        union
-        {
-            _Tp* __t;
-            size_t __a;
-        } __u;
-        __u.__t = __v;
-        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
-    }
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<bool>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<bool, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<char>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<char, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef char argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<signed char>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<signed char, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef signed char argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<unsigned char, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned char argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<char8_t, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef char8_t argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-#endif // !_LIBCPP_HAS_NO_CHAR8_T
-
-#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<char16_t, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef char16_t argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<char32_t, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef char32_t argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<wchar_t, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef wchar_t argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<short>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<short, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef short argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<unsigned short, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned short argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<int>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<int, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef int argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<unsigned int, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned int argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<long>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<long, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef long argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<unsigned long, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned long argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
-};
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<long long>
-    : public __scalar_hash<long long>
-{
-};
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
-    : public __scalar_hash<unsigned long long>
-{
-};
-
-#ifndef _LIBCPP_HAS_NO_INT128
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
-    : public __scalar_hash<__int128_t>
-{
-};
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
-    : public __scalar_hash<__uint128_t>
-{
-};
-
-#endif
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<float>
-    : public __scalar_hash<float>
-{
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(float __v) const _NOEXCEPT
-    {
-        // -0.0 and 0.0 should return same hash
-       if (__v == 0.0f)
-           return 0;
-        return __scalar_hash<float>::operator()(__v);
-    }
-};
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<double>
-    : public __scalar_hash<double>
-{
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(double __v) const _NOEXCEPT
-    {
-        // -0.0 and 0.0 should return same hash
-       if (__v == 0.0)
-           return 0;
-        return __scalar_hash<double>::operator()(__v);
-    }
-};
-
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<long double>
-    : public __scalar_hash<long double>
-{
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(long double __v) const _NOEXCEPT
-    {
-        // -0.0 and 0.0 should return same hash
-        if (__v == 0.0L)
-            return 0;
-#if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
-        // Zero out padding bits
-        union
-        {
-            long double __t;
-            struct
-            {
-                size_t __a;
-                size_t __b;
-                size_t __c;
-                size_t __d;
-            } __s;
-        } __u;
-        __u.__s.__a = 0;
-        __u.__s.__b = 0;
-        __u.__s.__c = 0;
-        __u.__s.__d = 0;
-        __u.__t = __v;
-        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
-#elif defined(__x86_64__)
-        // Zero out padding bits
-        union
-        {
-            long double __t;
-            struct
-            {
-                size_t __a;
-                size_t __b;
-            } __s;
-        } __u;
-        __u.__s.__a = 0;
-        __u.__s.__b = 0;
-        __u.__t = __v;
-        return __u.__s.__a ^ __u.__s.__b;
-#else
-        return __scalar_hash<long double>::operator()(__v);
-#endif
-    }
-};
-
-#if _LIBCPP_STD_VER > 11
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <class _Tp, bool = is_enum<_Tp>::value>
-struct _LIBCPP_TEMPLATE_VIS __enum_hash
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-    : public unary_function<_Tp, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(_Tp __v) const _NOEXCEPT
-    {
-        typedef typename underlying_type<_Tp>::type type;
-        return hash<type>{}(static_cast<type>(__v));
-    }
-};
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
-    __enum_hash() = delete;
-    __enum_hash(__enum_hash const&) = delete;
-    __enum_hash& operator=(__enum_hash const&) = delete;
-};
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
-{
-};
-#endif
-
-#if _LIBCPP_STD_VER > 14
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-template <>
-struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
-#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
-  : public unary_function<nullptr_t, size_t>
-#endif
-{
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
-    _LIBCPP_DEPRECATED_IN_CXX17 typedef nullptr_t argument_type;
-#endif
-    _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(nullptr_t) const _NOEXCEPT {
-        return 662607004ull;
-    }
-};
-#endif
-
-#ifndef _LIBCPP_CXX03_LANG
-template <class _Key, class _Hash>
-using __check_hash_requirements _LIBCPP_NODEBUG_TYPE  = integral_constant<bool,
-    is_copy_constructible<_Hash>::value &&
-    is_move_constructible<_Hash>::value &&
-    __invokable_r<size_t, _Hash, _Key const&>::value
->;
-
-template <class _Key, class _Hash = hash<_Key> >
-using __has_enabled_hash _LIBCPP_NODEBUG_TYPE = integral_constant<bool,
-    __check_hash_requirements<_Key, _Hash>::value &&
-    is_default_constructible<_Hash>::value
->;
-
-#if _LIBCPP_STD_VER > 14
-template <class _Type, class>
-using __enable_hash_helper_imp _LIBCPP_NODEBUG_TYPE  = _Type;
-
-template <class _Type, class ..._Keys>
-using __enable_hash_helper _LIBCPP_NODEBUG_TYPE  = __enable_hash_helper_imp<_Type,
-  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
->;
-#else
-template <class _Type, class ...>
-using __enable_hash_helper _LIBCPP_NODEBUG_TYPE = _Type;
-#endif
-
-#endif // !_LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_STD
-
-_LIBCPP_POP_MACROS
-
 #endif // _LIBCPP_UTILITY

diff  --git a/libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp b/libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp
index 5be63dd92c207..bce2c6fdfc228 100644
--- a/libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp
+++ b/libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/pair.tuple_element.fail.cpp
@@ -19,7 +19,7 @@ int main(int, char**)
     {
     typedef std::pair<int, double> P;
     std::tuple_element<2, P>::type foo; // expected-note {{requested here}}
-        // expected-error-re at utility:* {{static_assert failed{{( due to requirement '2U[L]{0,2} < 2')?}} "Index out of bounds in std::tuple_element<std::pair<T1, T2>>"}}
+        // expected-error-re@*:* {{static_assert failed{{( due to requirement '2U[L]{0,2} < 2')?}} "Index out of bounds in std::tuple_element<std::pair<T1, T2>>"}}
     }
 
   return 0;

diff  --git a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
index 09605ef843fea..8da2b67982e55 100644
--- a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
@@ -29,9 +29,9 @@ int main(int, char**)
   // std::make_integer_sequence is implemented using a compiler builtin if available.
   // this builtin has 
diff erent diagnostic messages than the fallback implementation.
 #if TEST_HAS_BUILTIN(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
-    MakeSeqT i; // expected-error at utility:* {{integer sequences must have non-negative sequence length}}
+  MakeSeqT i; // expected-error@*:* {{integer sequences must have non-negative sequence length}}
 #else
-    MakeSeqT i; // expected-error at utility:* {{static_assert failed "std::make_integer_sequence must have a non-negative sequence length"}}
+  MakeSeqT i; // expected-error@*:* {{static_assert failed "std::make_integer_sequence must have a non-negative sequence length"}}
 #endif
 
   return 0;

diff  --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
index 8dfe0c5f61836..08cbb587c9978 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
@@ -15,6 +15,8 @@
 
 #include <memory>
 
+#include <functional>
+
 #include "poisoned_hash_helper.h"
 
 #include "test_macros.h"

diff  --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
index 20bd6add26c1f..0c3915bf48041 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
@@ -17,7 +17,9 @@
 // };
 
 #include <memory>
+
 #include <cassert>
+#include <functional>
 
 #include "test_macros.h"
 

diff  --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
index ca243b42702b8..fc1500ff7f63e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
@@ -17,7 +17,9 @@
 // };
 
 #include <memory>
+
 #include <cassert>
+#include <functional>
 
 #include "test_macros.h"
 

diff  --git a/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
index 0a9993875b421..65f0d7d194d6f 100644
--- a/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
@@ -15,6 +15,8 @@
 
 #include <typeindex>
 
+#include <functional>
+
 #include "poisoned_hash_helper.h"
 
 #include "test_macros.h"

diff  --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
index e53ca898d2687..a9a16a42e5037 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
@@ -17,7 +17,7 @@
 int main(int, char**)
 {
     typedef std::pair<int, short> T;
-    std::tuple_element<2, T>::type foo; // expected-error at utility:* {{Index out of bounds in std::tuple_element<std::pair<T1, T2>>}}
+    std::tuple_element<2, T>::type foo; // expected-error@*:* {{Index out of bounds in std::tuple_element<std::pair<T1, T2>>}}
 
-  return 0;
+    return 0;
 }

diff  --git a/libcxx/test/std/utilities/utility/utility.underlying/to_underlying.pass.cpp b/libcxx/test/std/utilities/utility/utility.underlying/to_underlying.pass.cpp
index 337b86ab8949a..d57dfd43f5b77 100644
--- a/libcxx/test/std/utilities/utility/utility.underlying/to_underlying.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.underlying/to_underlying.pass.cpp
@@ -14,6 +14,7 @@
 
 #include <utility>
 #include <cassert>
+#include <cstdint>
 #include <limits>
 
 #include "test_macros.h"

diff  --git a/libcxx/test/support/poisoned_hash_helper.h b/libcxx/test/support/poisoned_hash_helper.h
index a1f5f79162e63..1a81ead61b1d4 100644
--- a/libcxx/test/support/poisoned_hash_helper.h
+++ b/libcxx/test/support/poisoned_hash_helper.h
@@ -9,9 +9,9 @@
 #ifndef SUPPORT_POISONED_HASH_HELPER_H
 #define SUPPORT_POISONED_HASH_HELPER_H
 
-#include <__utility/move.h> // TODO: replace with <utility> when std::hash is moved out of the header
 #include <cassert>
 #include <type_traits>
+#include <utility>
 
 #include "test_macros.h"
 #include "test_workarounds.h"