[libc++] Format the code base (#74334)

This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.

This patch was generated with:

   find libcxx/include libcxx/src -type f \
      | grep -v 'module.modulemap.in' \
      | grep -v 'CMakeLists.txt' \
      | grep -v 'README.txt' \
      | grep -v 'libcxx.imp' \
      | grep -v '__config_site.in' \
      | xargs clang-format -i

A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.

[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all

13 files changed, 196 insertions, 249 deletions

diff --git a/libcxx/include/__numeric/accumulate.h b/libcxx/include/__numeric/accumulate.h
index 1ab6c4b..fedc1c4 100644
--- a/libcxx/include/__numeric/accumulate.h
+++ b/libcxx/include/__numeric/accumulate.h
@@ -23,31 +23,27 @@ _LIBCPP_PUSH_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)
+_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;
+    __init = std::move(__init) + *__first;
 #else
-        __init = __init + *__first;
+    __init = __init + *__first;
 #endif
-    return __init;
+  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)
+_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);
+    __init = __binary_op(std::move(__init), *__first);
 #else
-        __init = __binary_op(__init, *__first);
+    __init = __binary_op(__init, *__first);
 #endif
-    return __init;
+  return __init;
 }
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/adjacent_difference.h b/libcxx/include/__numeric/adjacent_difference.h
index 31ffe9c..62b5334 100644
--- a/libcxx/include/__numeric/adjacent_difference.h
+++ b/libcxx/include/__numeric/adjacent_difference.h
@@ -24,50 +24,41 @@ _LIBCPP_PUSH_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);
+_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);
+      *__result = __val - std::move(__acc);
 #else
-            *__result = __val - __acc;
+      *__result = __val - __acc;
 #endif
-            __acc = std::move(__val);
-        }
+      __acc = std::move(__val);
     }
-    return __result;
+  }
+  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);
+_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));
+      *__result = __binary_op(__val, std::move(__acc));
 #else
-            *__result = __binary_op(__val, __acc);
+      *__result = __binary_op(__val, __acc);
 #endif
-            __acc = std::move(__val);
-        }
+      __acc = std::move(__val);
     }
-    return __result;
+  }
+  return __result;
 }
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/exclusive_scan.h b/libcxx/include/__numeric/exclusive_scan.h
index 8b4a5c8..af85b47 100644
--- a/libcxx/include/__numeric/exclusive_scan.h
+++ b/libcxx/include/__numeric/exclusive_scan.h
@@ -37,7 +37,7 @@ exclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __
       if (__first == __last)
         break;
       __init = std::move(__tmp);
-      __tmp = __b(__init, *__first);
+      __tmp  = __b(__init, *__first);
     }
   }
   return __result;
diff --git a/libcxx/include/__numeric/gcd_lcm.h b/libcxx/include/__numeric/gcd_lcm.h
index 693be70..3e9c244 100644
--- a/libcxx/include/__numeric/gcd_lcm.h
+++ b/libcxx/include/__numeric/gcd_lcm.h
@@ -30,65 +30,55 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
 
-template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __ct_abs;
+template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value>
+struct __ct_abs;
 
 template <typename _Result, typename _Source>
 struct __ct_abs<_Result, _Source, true> {
-    _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
-    _Result operator()(_Source __t) const noexcept
-    {
-        if (__t >= 0) return __t;
-        if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
-        return -__t;
-    }
+  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI _Result operator()(_Source __t) const noexcept {
+    if (__t >= 0)
+      return __t;
+    if (__t == numeric_limits<_Source>::min())
+      return -static_cast<_Result>(__t);
+    return -__t;
+  }
 };
 
 template <typename _Result, typename _Source>
 struct __ct_abs<_Result, _Source, false> {
-    _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
-    _Result operator()(_Source __t) const noexcept { return __t; }
+  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI _Result operator()(_Source __t) const noexcept { return __t; }
 };
 
-
-template<class _Tp>
-_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
-_Tp __gcd(_Tp __m, _Tp __n)
-{
-    static_assert((!is_signed<_Tp>::value), "");
-    return __n == 0 ? __m : std::__gcd<_Tp>(__n, __m % __n);
+template <class _Tp>
+_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN _Tp __gcd(_Tp __m, _Tp __n) {
+  static_assert((!is_signed<_Tp>::value), "");
+  return __n == 0 ? __m : std::__gcd<_Tp>(__n, __m % __n);
 }
 
-template<class _Tp, class _Up>
-_LIBCPP_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>;
-    return static_cast<_Rp>(std::__gcd(
-        static_cast<_Wp>(__ct_abs<_Rp, _Tp>()(__m)),
-        static_cast<_Wp>(__ct_abs<_Rp, _Up>()(__n))));
+template <class _Tp, class _Up>
+_LIBCPP_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>;
+  return static_cast<_Rp>(
+      std::__gcd(static_cast<_Wp>(__ct_abs<_Rp, _Tp>()(__m)), static_cast<_Wp>(__ct_abs<_Rp, _Up>()(__n))));
 }
 
-template<class _Tp, class _Up>
-_LIBCPP_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 = __ct_abs<_Rp, _Tp>()(__m) / std::gcd(__m, __n);
-    _Rp __val2 = __ct_abs<_Rp, _Up>()(__n);
-    _LIBCPP_ASSERT_UNCATEGORIZED((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
-    return __val1 * __val2;
+template <class _Tp, class _Up>
+_LIBCPP_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 = __ct_abs<_Rp, _Tp>()(__m) / std::gcd(__m, __n);
+  _Rp __val2 = __ct_abs<_Rp, _Up>()(__n);
+  _LIBCPP_ASSERT_UNCATEGORIZED((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
+  return __val1 * __val2;
 }
 
 #endif // _LIBCPP_STD_VER
diff --git a/libcxx/include/__numeric/inclusive_scan.h b/libcxx/include/__numeric/inclusive_scan.h
index 162b9e6..d714f10 100644
--- a/libcxx/include/__numeric/inclusive_scan.h
+++ b/libcxx/include/__numeric/inclusive_scan.h
@@ -27,7 +27,7 @@ template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryO
 _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);
+    __init    = __b(__init, *__first);
     *__result = __init;
   }
   return __result;
@@ -38,7 +38,7 @@ _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;
+    *__result++                                                 = __init;
     if (++__first != __last)
       return std::inclusive_scan(__first, __last, __result, __b, __init);
   }
@@ -47,9 +47,8 @@ inclusive_scan(_InputIterator __first, _InputIterator __last, _OutputIterator __
 }
 
 template <class _InputIterator, class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator inclusive_scan(_InputIterator __first,
-                                                                                       _InputIterator __last,
-                                                                                       _OutputIterator __result) {
+_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<>());
 }
 
diff --git a/libcxx/include/__numeric/inner_product.h b/libcxx/include/__numeric/inner_product.h
index 48f2ea3..0deab3d 100644
--- a/libcxx/include/__numeric/inner_product.h
+++ b/libcxx/include/__numeric/inner_product.h
@@ -23,32 +23,32 @@ _LIBCPP_PUSH_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)
+_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;
+    __init = std::move(__init) + *__first1 * *__first2;
 #else
-        __init = __init + *__first1 * *__first2;
+    __init = __init + *__first1 * *__first2;
 #endif
-    return __init;
+  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)
+_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));
+    __init = __binary_op1(std::move(__init), __binary_op2(*__first1, *__first2));
 #else
-        __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
+    __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
 #endif
-    return __init;
+  return __init;
 }
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/iota.h b/libcxx/include/__numeric/iota.h
index 473ca96..27bd84e 100644
--- a/libcxx/include/__numeric/iota.h
+++ b/libcxx/include/__numeric/iota.h
@@ -19,12 +19,10 @@
 _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_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
diff --git a/libcxx/include/__numeric/midpoint.h b/libcxx/include/__numeric/midpoint.h
index c92e450..986cb6e 100644
--- a/libcxx/include/__numeric/midpoint.h
+++ b/libcxx/include/__numeric/midpoint.h
@@ -35,55 +35,50 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
 template <class _Tp>
-_LIBCPP_HIDE_FROM_ABI constexpr
-enable_if_t<is_integral_v<_Tp> && !is_same_v<bool, _Tp> && !is_null_pointer_v<_Tp>, _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;
+_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<is_integral_v<_Tp> && !is_same_v<bool, _Tp> && !is_null_pointer_v<_Tp>, _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 __diff     = _Up(__b) - _Up(__a);
+  _Up __sign_bit = __b < __a;
 
-    _Up __half_diff = (__diff / 2) + (__sign_bit << __bitshift) + (__sign_bit & __diff);
+  _Up __half_diff = (__diff / 2) + (__sign_bit << __bitshift) + (__sign_bit & __diff);
 
-    return __a + __half_diff;
+  return __a + __half_diff;
 }
 
-
 template <class _TPtr>
-_LIBCPP_HIDE_FROM_ABI constexpr
-enable_if_t<is_pointer_v<_TPtr>
-             && is_object_v<remove_pointer_t<_TPtr>>
-             && ! is_void_v<remove_pointer_t<_TPtr>>
-             && (sizeof(remove_pointer_t<_TPtr>) > 0), _TPtr>
-midpoint(_TPtr __a, _TPtr __b) noexcept
-{
-    return __a + std::midpoint(ptrdiff_t(0), __b - __a);
+_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
+    is_pointer_v<_TPtr> && is_object_v<remove_pointer_t<_TPtr>> && !is_void_v<remove_pointer_t<_TPtr>> &&
+        (sizeof(remove_pointer_t<_TPtr>) > 0),
+    _TPtr>
+midpoint(_TPtr __a, _TPtr __b) noexcept {
+  return __a + std::midpoint(ptrdiff_t(0), __b - __a);
 }
 
-
 template <typename _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr int __sign(_Tp __val) {
-    return (_Tp(0) < __val) - (__val < _Tp(0));
+  return (_Tp(0) < __val) - (__val < _Tp(0));
 }
 
 template <typename _Fp>
-_LIBCPP_HIDE_FROM_ABI constexpr _Fp __fp_abs(_Fp __f) { return __f >= 0 ? __f : -__f; }
+_LIBCPP_HIDE_FROM_ABI constexpr _Fp __fp_abs(_Fp __f) {
+  return __f >= 0 ? __f : -__f;
+}
 
 template <class _Fp>
-_LIBCPP_HIDE_FROM_ABI constexpr
-enable_if_t<is_floating_point_v<_Fp>, _Fp>
-midpoint(_Fp __a, _Fp __b) noexcept
-{
-    constexpr _Fp __lo = numeric_limits<_Fp>::min()*2;
-    constexpr _Fp __hi = numeric_limits<_Fp>::max()/2;
-    return std::__fp_abs(__a) <= __hi && std::__fp_abs(__b) <= __hi ?  // typical case: overflow is impossible
-      (__a + __b)/2 :                                        // always correctly rounded
-      std::__fp_abs(__a) < __lo ? __a + __b/2 :                   // not safe to halve a
-      std::__fp_abs(__b) < __lo ? __a/2 + __b :                   // not safe to halve b
-      __a/2 + __b/2;                                         // otherwise correctly rounded
+_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<is_floating_point_v<_Fp>, _Fp> midpoint(_Fp __a, _Fp __b) noexcept {
+  constexpr _Fp __lo = numeric_limits<_Fp>::min() * 2;
+  constexpr _Fp __hi = numeric_limits<_Fp>::max() / 2;
+  return std::__fp_abs(__a) <= __hi && std::__fp_abs(__b) <= __hi
+           ? // typical case: overflow is impossible
+             (__a + __b) / 2
+           :                                             // always correctly rounded
+             std::__fp_abs(__a) < __lo ? __a + __b / 2 : // not safe to halve a
+                 std::__fp_abs(__b) < __lo ? __a / 2 + __b
+                                           : // not safe to halve b
+                 __a / 2 + __b / 2;          // otherwise correctly rounded
 }
 
 #endif // _LIBCPP_STD_VER >= 20
diff --git a/libcxx/include/__numeric/partial_sum.h b/libcxx/include/__numeric/partial_sum.h
index 49afcbb..7c3cf7f 100644
--- a/libcxx/include/__numeric/partial_sum.h
+++ b/libcxx/include/__numeric/partial_sum.h
@@ -24,48 +24,39 @@ _LIBCPP_PUSH_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)
-        {
+_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;
+      __t = std::move(__t) + *__first;
 #else
-            __t = __t + *__first;
+      __t = __t + *__first;
 #endif
-            *__result = __t;
-        }
+      *__result = __t;
     }
-    return __result;
+  }
+  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)
-        {
+_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);
+      __t = __binary_op(std::move(__t), *__first);
 #else
-            __t = __binary_op(__t, *__first);
+      __t = __binary_op(__t, *__first);
 #endif
-            *__result = __t;
-        }
+      *__result = __t;
     }
-    return __result;
+  }
+  return __result;
 }
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/reduce.h b/libcxx/include/__numeric/reduce.h
index eb53053..1aeefce 100644
--- a/libcxx/include/__numeric/reduce.h
+++ b/libcxx/include/__numeric/reduce.h
@@ -23,16 +23,16 @@ _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) {
+_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) {
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init) {
   return std::reduce(__first, __last, __init, std::plus<>());
 }
 
diff --git a/libcxx/include/__numeric/transform_exclusive_scan.h b/libcxx/include/__numeric/transform_exclusive_scan.h
index b8d7bd2..fb88aa5 100644
--- a/libcxx/include/__numeric/transform_exclusive_scan.h
+++ b/libcxx/include/__numeric/transform_exclusive_scan.h
@@ -20,26 +20,19 @@ _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;
+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
diff --git a/libcxx/include/__numeric/transform_inclusive_scan.h b/libcxx/include/__numeric/transform_inclusive_scan.h
index e1b818c..2eab1a1 100644
--- a/libcxx/include/__numeric/transform_inclusive_scan.h
+++ b/libcxx/include/__numeric/transform_inclusive_scan.h
@@ -22,33 +22,27 @@ _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;
+_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;
+_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
diff --git a/libcxx/include/__numeric/transform_reduce.h b/libcxx/include/__numeric/transform_reduce.h
index 04d02b6..6c0a81e 100644
--- a/libcxx/include/__numeric/transform_reduce.h
+++ b/libcxx/include/__numeric/transform_reduce.h
@@ -22,30 +22,30 @@ _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) {
+_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) {
+_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<>());
+_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