lib: establish Zircon libc++ and KTL foundation

16 files changed, 1194 insertions, 0 deletions

diff --git a/third_party/libcxx/include/c++/v1/__numeric/accumulate.h b/third_party/libcxx/include/c++/v1/__numeric/accumulate.h
new file mode 100644
index 0000000..fedc1c4
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/accumulate.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_ACCUMULATE_H
+#define _LIBCPP___NUMERIC_ACCUMULATE_H
+
+#include <__config>
+#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
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+accumulate(_InputIterator __first, _InputIterator __last, _Tp __init) {
+  for (; __first != __last; ++__first)
+#if _LIBCPP_STD_VER >= 20
+    __init = std::move(__init) + *__first;
+#else
+    __init = __init + *__first;
+#endif
+  return __init;
+}
+
+template <class _InputIterator, class _Tp, class _BinaryOperation>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOperation __binary_op) {
+  for (; __first != __last; ++__first)
+#if _LIBCPP_STD_VER >= 20
+    __init = __binary_op(std::move(__init), *__first);
+#else
+    __init = __binary_op(__init, *__first);
+#endif
+  return __init;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_ACCUMULATE_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/adjacent_difference.h b/third_party/libcxx/include/c++/v1/__numeric/adjacent_difference.h
new file mode 100644
index 0000000..62b5334
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/adjacent_difference.h
@@ -0,0 +1,68 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_ADJACENT_DIFFERENCE_H
+#define _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
+
+#include <__config>
+#include <__iterator/iterator_traits.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
+
+template <class _InputIterator, class _OutputIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
+  if (__first != __last) {
+    typename iterator_traits<_InputIterator>::value_type __acc(*__first);
+    *__result = __acc;
+    for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
+      typename iterator_traits<_InputIterator>::value_type __val(*__first);
+#if _LIBCPP_STD_VER >= 20
+      *__result = __val - std::move(__acc);
+#else
+      *__result = __val - __acc;
+#endif
+      __acc = std::move(__val);
+    }
+  }
+  return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator adjacent_difference(
+    _InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
+  if (__first != __last) {
+    typename iterator_traits<_InputIterator>::value_type __acc(*__first);
+    *__result = __acc;
+    for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
+      typename iterator_traits<_InputIterator>::value_type __val(*__first);
+#if _LIBCPP_STD_VER >= 20
+      *__result = __binary_op(__val, std::move(__acc));
+#else
+      *__result = __binary_op(__val, __acc);
+#endif
+      __acc = std::move(__val);
+    }
+  }
+  return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_ADJACENT_DIFFERENCE_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/exclusive_scan.h b/third_party/libcxx/include/c++/v1/__numeric/exclusive_scan.h
new file mode 100644
index 0000000..af85b47
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/exclusive_scan.h
@@ -0,0 +1,58 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_EXCLUSIVE_SCAN_H
+#define _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H
+
+#include <__config>
+#include <__functional/operations.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 >= 17
+
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init, _BinaryOp __b) {
+  if (__first != __last) {
+    _Tp __tmp(__b(__init, *__first));
+    while (true) {
+      *__result = std::move(__init);
+      ++__result;
+      ++__first;
+      if (__first == __last)
+        break;
+      __init = std::move(__tmp);
+      __tmp  = __b(__init, *__first);
+    }
+  }
+  return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init) {
+  return std::exclusive_scan(__first, __last, __result, __init, std::plus<>());
+}
+
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_EXCLUSIVE_SCAN_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/gcd_lcm.h b/third_party/libcxx/include/c++/v1/__numeric/gcd_lcm.h
new file mode 100644
index 0000000..5ab870f
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/gcd_lcm.h
@@ -0,0 +1,120 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_GCD_LCM_H
+#define _LIBCPP___NUMERIC_GCD_LCM_H
+
+#include <__assert>
+#include <__bit/countr.h>
+#include <__config>
+#include <__memory/addressof.h>
+#include <__type_traits/common_type.h>
+#include <__type_traits/is_integral.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/is_signed.h>
+#include <__type_traits/make_unsigned.h>
+#include <__type_traits/remove_cv.h>
+#include <limits>
+
+#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
+
+template <class _Result, class _Source>
+constexpr _LIBCPP_HIDE_FROM_ABI _Result __abs_in_type(_Source __t) noexcept {
+  if constexpr (is_signed_v<_Source>) {
+    if (__t >= 0)
+      return __t;
+    if (__t == numeric_limits<_Source>::min())
+      return -static_cast<_Result>(__t);
+    return -__t;
+  } else {
+    return __t;
+  }
+}
+
+template <class _Tp, class _Up>
+constexpr _LIBCPP_HIDE_FROM_ABI common_type_t<_Tp, _Up> gcd(_Tp __m, _Up __n) {
+  static_assert(is_integral<_Tp>::value && is_integral<_Up>::value, "Arguments to gcd must be integer types");
+  static_assert(!is_same<__remove_cv_t<_Tp>, bool>::value, "First argument to gcd cannot be bool");
+  static_assert(!is_same<__remove_cv_t<_Up>, bool>::value, "Second argument to gcd cannot be bool");
+  using _Rp = common_type_t<_Tp, _Up>;
+  using _Wp = make_unsigned_t<_Rp>;
+
+  // Using Binary GCD algorithm https://en.wikipedia.org/wiki/Binary_GCD_algorithm, based on an implementation
+  // from https://lemire.me/blog/2024/04/13/greatest-common-divisor-the-extended-euclidean-algorithm-and-speed/
+  //
+  // If power of two divides both numbers, we can push it out.
+  // - gcd( 2^x * a, 2^x * b) = 2^x * gcd(a, b)
+  //
+  // If and only if exactly one number is even, we can divide that number by that power.
+  // - if a, b are odd, then gcd(2^x * a, b) = gcd(a, b)
+  //
+  // And standard gcd algorithm where instead of modulo, minus is used.
+
+  auto __a = static_cast<_Wp>(std::__abs_in_type<_Rp>(__m));
+  auto __b = static_cast<_Wp>(std::__abs_in_type<_Rp>(__n));
+
+  if (__a < __b) {
+    _Wp __tmp = __b;
+    __b       = __a;
+    __a       = __tmp;
+  }
+  if (__b == 0)
+    return static_cast<_Rp>(__a);
+  __a %= __b; // Make both argument of the same size, and early result in the easy case.
+  if (__a == 0)
+    return static_cast<_Rp>(__b);
+
+  _Wp __c     = __a | __b;
+  int __shift = std::__countr_zero(__c);
+  __a >>= std::__countr_zero(__a);
+  do {
+    _Wp __t = __b >> std::__countr_zero(__b);
+    if (__a > __t) {
+      __b = __a - __t;
+      __a = __t;
+    } else {
+      __b = __t - __a;
+    }
+  } while (__b != 0);
+  return static_cast<_Rp>(__a << __shift);
+}
+
+template <class _Tp, class _Up>
+constexpr _LIBCPP_HIDE_FROM_ABI common_type_t<_Tp, _Up> lcm(_Tp __m, _Up __n) {
+  static_assert(is_integral<_Tp>::value && is_integral<_Up>::value, "Arguments to lcm must be integer types");
+  static_assert(!is_same<__remove_cv_t<_Tp>, bool>::value, "First argument to lcm cannot be bool");
+  static_assert(!is_same<__remove_cv_t<_Up>, bool>::value, "Second argument to lcm cannot be bool");
+  if (__m == 0 || __n == 0)
+    return 0;
+
+  using _Rp  = common_type_t<_Tp, _Up>;
+  _Rp __val1 = std::__abs_in_type<_Rp>(__m) / std::gcd(__m, __n);
+  _Rp __val2 = std::__abs_in_type<_Rp>(__n);
+  _Rp __res;
+  [[maybe_unused]] bool __overflow = __builtin_mul_overflow(__val1, __val2, std::addressof(__res));
+  _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(!__overflow, "Overflow in lcm");
+  return __res;
+}
+
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_GCD_LCM_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/inclusive_scan.h b/third_party/libcxx/include/c++/v1/__numeric/inclusive_scan.h
new file mode 100644
index 0000000..d714f10
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/inclusive_scan.h
@@ -0,0 +1,59 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_INCLUSIVE_SCAN_H
+#define _LIBCPP___NUMERIC_INCLUSIVE_SCAN_H
+
+#include <__config>
+#include <__functional/operations.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOp __b, _Tp __init) {
+  for (; __first != __last; ++__first, (void)++__result) {
+    __init    = __b(__init, *__first);
+    *__result = __init;
+  }
+  return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOp __b) {
+  if (__first != __last) {
+    typename iterator_traits<_InputIterator>::value_type __init = *__first;
+    *__result++                                                 = __init;
+    if (++__first != __last)
+      return std::inclusive_scan(__first, __last, __result, __b, __init);
+  }
+
+  return __result;
+}
+
+template <class _InputIterator, class _OutputIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
+  return std::inclusive_scan(__first, __last, __result, std::plus<>());
+}
+
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___NUMERIC_INCLUSIVE_SCAN_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/inner_product.h b/third_party/libcxx/include/c++/v1/__numeric/inner_product.h
new file mode 100644
index 0000000..0deab3d
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/inner_product.h
@@ -0,0 +1,58 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_INNER_PRODUCT_H
+#define _LIBCPP___NUMERIC_INNER_PRODUCT_H
+
+#include <__config>
+#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
+
+template <class _InputIterator1, class _InputIterator2, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _Tp __init) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+#if _LIBCPP_STD_VER >= 20
+    __init = std::move(__init) + *__first1 * *__first2;
+#else
+    __init = __init + *__first1 * *__first2;
+#endif
+  return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp inner_product(
+    _InputIterator1 __first1,
+    _InputIterator1 __last1,
+    _InputIterator2 __first2,
+    _Tp __init,
+    _BinaryOperation1 __binary_op1,
+    _BinaryOperation2 __binary_op2) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+#if _LIBCPP_STD_VER >= 20
+    __init = __binary_op1(std::move(__init), __binary_op2(*__first1, *__first2));
+#else
+    __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
+#endif
+  return __init;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_INNER_PRODUCT_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/iota.h b/third_party/libcxx/include/c++/v1/__numeric/iota.h
new file mode 100644
index 0000000..27bd84e
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/iota.h
@@ -0,0 +1,30 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_IOTA_H
+#define _LIBCPP___NUMERIC_IOTA_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
+iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value) {
+  for (; __first != __last; ++__first, (void)++__value)
+    *__first = __value;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___NUMERIC_IOTA_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/midpoint.h b/third_party/libcxx/include/c++/v1/__numeric/midpoint.h
new file mode 100644
index 0000000..d8e73ab
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/midpoint.h
@@ -0,0 +1,83 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_MIDPOINT_H
+#define _LIBCPP___NUMERIC_MIDPOINT_H
+
+#include <__config>
+#include <__cstddef/ptrdiff_t.h>
+#include <__type_traits/is_floating_point.h>
+#include <__type_traits/is_integral.h>
+#include <__type_traits/is_object.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/is_void.h>
+#include <__type_traits/make_unsigned.h>
+#include <__type_traits/remove_cv.h>
+#include <limits>
+
+#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 >= 20
+template <class _Tp>
+  requires(is_integral_v<_Tp> && !is_same_v<remove_cv_t<_Tp>, bool>)
+[[nodiscard]]
+_LIBCPP_HIDE_FROM_ABI constexpr _Tp midpoint(_Tp __a, _Tp __b) noexcept _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK {
+  using _Up                = make_unsigned_t<_Tp>;
+  constexpr _Up __bitshift = numeric_limits<_Up>::digits - 1;
+
+  _Up __diff     = _Up(__b) - _Up(__a);
+  _Up __sign_bit = __b < __a;
+
+  _Up __half_diff = (__diff / 2) + (__sign_bit << __bitshift) + (__sign_bit & __diff);
+
+  return __a + __half_diff;
+}
+
+template <class _Tp>
+  requires(is_object_v<_Tp> && (sizeof(_Tp) > 0))
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp* midpoint(_Tp* __a, _Tp* __b) noexcept {
+  return __a + std::midpoint(ptrdiff_t(0), __b - __a);
+}
+
+template <typename _Fp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Fp __fp_abs(_Fp __f) {
+  return __f >= 0 ? __f : -__f;
+}
+
+template <class _Fp>
+  requires(is_floating_point_v<_Fp>)
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Fp midpoint(_Fp __a, _Fp __b) noexcept {
+  constexpr _Fp __lo = numeric_limits<_Fp>::min() * 2;
+  constexpr _Fp __hi = numeric_limits<_Fp>::max() / 2;
+
+  // typical case: overflow is impossible
+  if (std::__fp_abs(__a) <= __hi && std::__fp_abs(__b) <= __hi)
+    return (__a + __b) / 2; // always correctly rounded
+  if (std::__fp_abs(__a) < __lo)
+    return __a + __b / 2; // not safe to halve a
+  if (std::__fp_abs(__b) < __lo)
+    return __a / 2 + __b; // not safe to halve b
+
+  return __a / 2 + __b / 2; // otherwise correctly rounded
+}
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_MIDPOINT_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/partial_sum.h b/third_party/libcxx/include/c++/v1/__numeric/partial_sum.h
new file mode 100644
index 0000000..7c3cf7f
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/partial_sum.h
@@ -0,0 +1,66 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_PARTIAL_SUM_H
+#define _LIBCPP___NUMERIC_PARTIAL_SUM_H
+
+#include <__config>
+#include <__iterator/iterator_traits.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
+
+template <class _InputIterator, class _OutputIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
+  if (__first != __last) {
+    typename iterator_traits<_InputIterator>::value_type __t(*__first);
+    *__result = __t;
+    for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
+#if _LIBCPP_STD_VER >= 20
+      __t = std::move(__t) + *__first;
+#else
+      __t = __t + *__first;
+#endif
+      *__result = __t;
+    }
+  }
+  return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOperation __binary_op) {
+  if (__first != __last) {
+    typename iterator_traits<_InputIterator>::value_type __t(*__first);
+    *__result = __t;
+    for (++__first, (void)++__result; __first != __last; ++__first, (void)++__result) {
+#if _LIBCPP_STD_VER >= 20
+      __t = __binary_op(std::move(__t), *__first);
+#else
+      __t = __binary_op(__t, *__first);
+#endif
+      *__result = __t;
+    }
+  }
+  return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_PARTIAL_SUM_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/pstl.h b/third_party/libcxx/include/c++/v1/__numeric/pstl.h
new file mode 100644
index 0000000..fe7b2cc
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/pstl.h
@@ -0,0 +1,174 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_PSTL_H
+#define _LIBCPP___NUMERIC_PSTL_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_HAS_EXPERIMENTAL_PSTL && _LIBCPP_STD_VER >= 17
+
+#  include <__functional/identity.h>
+#  include <__functional/operations.h>
+#  include <__iterator/cpp17_iterator_concepts.h>
+#  include <__iterator/iterator_traits.h>
+#  include <__pstl/backend.h>
+#  include <__pstl/dispatch.h>
+#  include <__pstl/handle_exception.h>
+#  include <__type_traits/enable_if.h>
+#  include <__type_traits/is_execution_policy.h>
+#  include <__type_traits/remove_cvref.h>
+#  include <__utility/forward.h>
+#  include <__utility/move.h>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Tp,
+          class _BinaryOperation,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _Tp reduce(
+    _ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Tp __init, _BinaryOperation __op) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "reduce requires ForwardIterators");
+  using _Implementation = __pstl::__dispatch<__pstl::__reduce, __pstl::__current_configuration, _RawPolicy>;
+  return __pstl::__handle_exception<_Implementation>(
+      std::forward<_ExecutionPolicy>(__policy),
+      std::move(__first),
+      std::move(__last),
+      std::move(__init),
+      std::move(__op));
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Tp,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _Tp
+reduce(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Tp __init) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "reduce requires ForwardIterators");
+  using _Implementation = __pstl::__dispatch<__pstl::__reduce, __pstl::__current_configuration, _RawPolicy>;
+  return __pstl::__handle_exception<_Implementation>(
+      std::forward<_ExecutionPolicy>(__policy), std::move(__first), std::move(__last), std::move(__init), plus{});
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI __iterator_value_type<_ForwardIterator>
+reduce(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "reduce requires ForwardIterators");
+  using _Implementation = __pstl::__dispatch<__pstl::__reduce, __pstl::__current_configuration, _RawPolicy>;
+  return __pstl::__handle_exception<_Implementation>(
+      std::forward<_ExecutionPolicy>(__policy),
+      std::move(__first),
+      std::move(__last),
+      __iterator_value_type<_ForwardIterator>(),
+      plus{});
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator1,
+          class _ForwardIterator2,
+          class _Tp,
+          class _BinaryOperation1,
+          class _BinaryOperation2,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _Tp transform_reduce(
+    _ExecutionPolicy&& __policy,
+    _ForwardIterator1 __first1,
+    _ForwardIterator1 __last1,
+    _ForwardIterator2 __first2,
+    _Tp __init,
+    _BinaryOperation1 __reduce,
+    _BinaryOperation2 __transform) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "transform_reduce requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "transform_reduce requires ForwardIterators");
+  using _Implementation =
+      __pstl::__dispatch<__pstl::__transform_reduce_binary, __pstl::__current_configuration, _RawPolicy>;
+  return __pstl::__handle_exception<_Implementation>(
+      std::forward<_ExecutionPolicy>(__policy),
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__init),
+      std::move(__reduce),
+      std::move(__transform));
+}
+
+// This overload doesn't get a customization point because it's trivial to detect (through e.g.
+// __desugars_to_v) when specializing the more general variant, which should always be preferred
+template <class _ExecutionPolicy,
+          class _ForwardIterator1,
+          class _ForwardIterator2,
+          class _Tp,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _Tp transform_reduce(
+    _ExecutionPolicy&& __policy,
+    _ForwardIterator1 __first1,
+    _ForwardIterator1 __last1,
+    _ForwardIterator2 __first2,
+    _Tp __init) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "transform_reduce requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "transform_reduce requires ForwardIterators");
+  using _Implementation =
+      __pstl::__dispatch<__pstl::__transform_reduce_binary, __pstl::__current_configuration, _RawPolicy>;
+  return __pstl::__handle_exception<_Implementation>(
+      std::forward<_ExecutionPolicy>(__policy),
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__init),
+      plus{},
+      multiplies{});
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Tp,
+          class _BinaryOperation,
+          class _UnaryOperation,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _Tp transform_reduce(
+    _ExecutionPolicy&& __policy,
+    _ForwardIterator __first,
+    _ForwardIterator __last,
+    _Tp __init,
+    _BinaryOperation __reduce,
+    _UnaryOperation __transform) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "transform_reduce requires ForwardIterators");
+  using _Implementation = __pstl::__dispatch<__pstl::__transform_reduce, __pstl::__current_configuration, _RawPolicy>;
+  return __pstl::__handle_exception<_Implementation>(
+      std::forward<_ExecutionPolicy>(__policy),
+      std::move(__first),
+      std::move(__last),
+      std::move(__init),
+      std::move(__reduce),
+      std::move(__transform));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_HAS_EXPERIMENTAL_PSTL && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_PSTL_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/ranges_iota.h b/third_party/libcxx/include/c++/v1/__numeric/ranges_iota.h
new file mode 100644
index 0000000..bf53dd8
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/ranges_iota.h
@@ -0,0 +1,65 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_RANGES_IOTA_H
+#define _LIBCPP___NUMERIC_RANGES_IOTA_H
+
+#include <__algorithm/out_value_result.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/as_const.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 >= 23
+namespace ranges {
+template <typename _Out, typename _Tp>
+using iota_result = ranges::out_value_result<_Out, _Tp>;
+
+struct __iota_fn {
+public:
+  template <input_or_output_iterator _Out, sentinel_for<_Out> _Sent, weakly_incrementable _Tp>
+    requires indirectly_writable<_Out, const _Tp&>
+  _LIBCPP_HIDE_FROM_ABI static constexpr iota_result<_Out, _Tp> operator()(_Out __first, _Sent __last, _Tp __value) {
+    while (__first != __last) {
+      *__first = std::as_const(__value);
+      ++__first;
+      ++__value;
+    }
+    return {std::move(__first), std::move(__value)};
+  }
+
+  template <weakly_incrementable _Tp, ranges::output_range<const _Tp&> _Range>
+  _LIBCPP_HIDE_FROM_ABI static constexpr iota_result<ranges::borrowed_iterator_t<_Range>, _Tp>
+  operator()(_Range&& __r, _Tp __value) {
+    return operator()(ranges::begin(__r), ranges::end(__r), std::move(__value));
+  }
+};
+
+inline constexpr auto iota = __iota_fn{};
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 23
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_RANGES_IOTA_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/reduce.h b/third_party/libcxx/include/c++/v1/__numeric/reduce.h
new file mode 100644
index 0000000..6c205bf
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/reduce.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_REDUCE_H
+#define _LIBCPP___NUMERIC_REDUCE_H
+
+#include <__config>
+#include <__functional/operations.h>
+#include <__iterator/iterator_traits.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 >= 17
+template <class _InputIterator, class _Tp, class _BinaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOp __b) {
+  for (; __first != __last; ++__first)
+    __init = __b(std::move(__init), *__first);
+  return __init;
+}
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init) {
+  return std::reduce(__first, __last, __init, std::plus<>());
+}
+
+template <class _InputIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 typename iterator_traits<_InputIterator>::value_type
+reduce(_InputIterator __first, _InputIterator __last) {
+  return std::reduce(__first, __last, typename iterator_traits<_InputIterator>::value_type{});
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_REDUCE_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/saturation_arithmetic.h b/third_party/libcxx/include/c++/v1/__numeric/saturation_arithmetic.h
new file mode 100644
index 0000000..34f784e
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/saturation_arithmetic.h
@@ -0,0 +1,154 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_SATURATION_ARITHMETIC_H
+#define _LIBCPP___NUMERIC_SATURATION_ARITHMETIC_H
+
+#include <__assert>
+#include <__config>
+#include <__memory/addressof.h>
+#include <__type_traits/integer_traits.h>
+#include <__utility/cmp.h>
+#include <limits>
+
+#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 >= 20
+
+template <__signed_or_unsigned_integer _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Tp __saturating_add(_Tp __x, _Tp __y) noexcept {
+#  if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 2101
+  return __builtin_elementwise_add_sat(__x, __y);
+#  else
+  if (_Tp __sum; !__builtin_add_overflow(__x, __y, std::addressof(__sum)))
+    return __sum;
+  // Handle overflow
+  if constexpr (__unsigned_integer<_Tp>) {
+    return std::numeric_limits<_Tp>::max();
+  } else {
+    // Signed addition overflow
+    if (__x > 0)
+      // Overflows if (x > 0 && y > 0)
+      return std::numeric_limits<_Tp>::max();
+    else
+      // Overflows if  (x < 0 && y < 0)
+      return std::numeric_limits<_Tp>::min();
+  }
+#  endif
+}
+
+template <__signed_or_unsigned_integer _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Tp __saturating_sub(_Tp __x, _Tp __y) noexcept {
+#  if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 2101
+  return __builtin_elementwise_sub_sat(__x, __y);
+#  else
+  if (_Tp __sub; !__builtin_sub_overflow(__x, __y, std::addressof(__sub)))
+    return __sub;
+  // Handle overflow
+  if constexpr (__unsigned_integer<_Tp>) {
+    // Overflows if (x < y)
+    return std::numeric_limits<_Tp>::min();
+  } else {
+    // Signed subtration overflow
+    if (__x >= 0)
+      // Overflows if (x >= 0 && y < 0)
+      return std::numeric_limits<_Tp>::max();
+    else
+      // Overflows if (x < 0 && y > 0)
+      return std::numeric_limits<_Tp>::min();
+  }
+#  endif
+}
+
+template <__signed_or_unsigned_integer _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Tp __saturating_mul(_Tp __x, _Tp __y) noexcept {
+  if (_Tp __mul; !__builtin_mul_overflow(__x, __y, std::addressof(__mul)))
+    return __mul;
+  // Handle overflow
+  if constexpr (__unsigned_integer<_Tp>) {
+    return std::numeric_limits<_Tp>::max();
+  } else {
+    // Signed multiplication overflow
+    if ((__x > 0 && __y > 0) || (__x < 0 && __y < 0))
+      return std::numeric_limits<_Tp>::max();
+    // Overflows if (x < 0 && y > 0) || (x > 0 && y < 0)
+    return std::numeric_limits<_Tp>::min();
+  }
+}
+
+template <__signed_or_unsigned_integer _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Tp __saturating_div(_Tp __x, _Tp __y) noexcept {
+  _LIBCPP_ASSERT_UNCATEGORIZED(__y != 0, "Division by 0 is undefined");
+  if constexpr (__unsigned_integer<_Tp>) {
+    return __x / __y;
+  } else {
+    // Handle signed division overflow
+    if (__x == std::numeric_limits<_Tp>::min() && __y == _Tp{-1})
+      return std::numeric_limits<_Tp>::max();
+    return __x / __y;
+  }
+}
+
+template <__signed_or_unsigned_integer _Rp, __signed_or_unsigned_integer _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr _Rp __saturating_cast(_Tp __x) noexcept {
+  // Saturation is impossible edge case when ((min _Rp) < (min _Tp) && (max _Rp) > (max _Tp)) and it is expected to be
+  // optimized out by the compiler.
+
+  // Handle overflow
+  if (std::cmp_less(__x, std::numeric_limits<_Rp>::min()))
+    return std::numeric_limits<_Rp>::min();
+  if (std::cmp_greater(__x, std::numeric_limits<_Rp>::max()))
+    return std::numeric_limits<_Rp>::max();
+  // No overflow
+  return static_cast<_Rp>(__x);
+}
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#if _LIBCPP_STD_VER >= 26
+
+template <__signed_or_unsigned_integer _Tp>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp saturating_add(_Tp __x, _Tp __y) noexcept {
+  return std::__saturating_add(__x, __y);
+}
+
+template <__signed_or_unsigned_integer _Tp>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp saturating_sub(_Tp __x, _Tp __y) noexcept {
+  return std::__saturating_sub(__x, __y);
+}
+
+template <__signed_or_unsigned_integer _Tp>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp saturating_mul(_Tp __x, _Tp __y) noexcept {
+  return std::__saturating_mul(__x, __y);
+}
+
+template <__signed_or_unsigned_integer _Tp>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp saturating_div(_Tp __x, _Tp __y) noexcept {
+  return std::__saturating_div(__x, __y);
+}
+
+template <__signed_or_unsigned_integer _Rp, __signed_or_unsigned_integer _Tp>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Rp saturating_cast(_Tp __x) noexcept {
+  return std::__saturating_cast<_Rp>(__x);
+}
+
+#endif // _LIBCPP_STD_VER >= 26
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_SATURATION_ARITHMETIC_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/transform_exclusive_scan.h b/third_party/libcxx/include/c++/v1/__numeric/transform_exclusive_scan.h
new file mode 100644
index 0000000..fb88aa5
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/transform_exclusive_scan.h
@@ -0,0 +1,42 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_TRANSFORM_EXCLUSIVE_SCAN_H
+#define _LIBCPP___NUMERIC_TRANSFORM_EXCLUSIVE_SCAN_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator transform_exclusive_scan(
+    _InputIterator __first, _InputIterator __last, _OutputIterator __result, _Tp __init, _BinaryOp __b, _UnaryOp __u) {
+  if (__first != __last) {
+    _Tp __saved = __init;
+    do {
+      __init    = __b(__init, __u(*__first));
+      *__result = __saved;
+      __saved   = __init;
+      ++__result;
+    } while (++__first != __last);
+  }
+  return __result;
+}
+
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___NUMERIC_TRANSFORM_EXCLUSIVE_SCAN_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/transform_inclusive_scan.h b/third_party/libcxx/include/c++/v1/__numeric/transform_inclusive_scan.h
new file mode 100644
index 0000000..2eab1a1
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/transform_inclusive_scan.h
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_TRANSFORM_INCLUSIVE_SCAN_H
+#define _LIBCPP___NUMERIC_TRANSFORM_INCLUSIVE_SCAN_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator transform_inclusive_scan(
+    _InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOp __b, _UnaryOp __u, _Tp __init) {
+  for (; __first != __last; ++__first, (void)++__result) {
+    __init    = __b(__init, __u(*__first));
+    *__result = __init;
+  }
+
+  return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOp, class _UnaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator transform_inclusive_scan(
+    _InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryOp __b, _UnaryOp __u) {
+  if (__first != __last) {
+    typename iterator_traits<_InputIterator>::value_type __init = __u(*__first);
+    *__result++                                                 = __init;
+    if (++__first != __last)
+      return std::transform_inclusive_scan(__first, __last, __result, __b, __u, __init);
+  }
+
+  return __result;
+}
+
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___NUMERIC_TRANSFORM_INCLUSIVE_SCAN_H
diff --git a/third_party/libcxx/include/c++/v1/__numeric/transform_reduce.h b/third_party/libcxx/include/c++/v1/__numeric/transform_reduce.h
new file mode 100644
index 0000000..f115051
--- /dev/null
+++ b/third_party/libcxx/include/c++/v1/__numeric/transform_reduce.h
@@ -0,0 +1,59 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_TRANSFORM_REDUCE_H
+#define _LIBCPP___NUMERIC_TRANSFORM_REDUCE_H
+
+#include <__config>
+#include <__functional/operations.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 >= 17
+template <class _InputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+transform_reduce(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOp __b, _UnaryOp __u) {
+  for (; __first != __last; ++__first)
+    __init = __b(std::move(__init), __u(*__first));
+  return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp, class _BinaryOp1, class _BinaryOp2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp transform_reduce(
+    _InputIterator1 __first1,
+    _InputIterator1 __last1,
+    _InputIterator2 __first2,
+    _Tp __init,
+    _BinaryOp1 __b1,
+    _BinaryOp2 __b2) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    __init = __b1(std::move(__init), __b2(*__first1, *__first2));
+  return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _Tp __init) {
+  return std::transform_reduce(__first1, __last1, __first2, std::move(__init), std::plus<>(), std::multiplies<>());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_TRANSFORM_REDUCE_H