From 7fa27ce4a07f19b07799a767fc29416f3b625afb Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Wed, 26 Jul 2023 21:03:47 +0200
Subject: Vendor import of llvm-project main
 llvmorg-17-init-19304-gd0b54bb50e51, the last commit before the upstream
 release/17.x branch was created.

---
 libcxx/include/__algorithm/copy.h | 40 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

(limited to 'libcxx/include/__algorithm/copy.h')

diff --git a/libcxx/include/__algorithm/copy.h b/libcxx/include/__algorithm/copy.h
index 193a6df31656..dfe9898c6480 100644
--- a/libcxx/include/__algorithm/copy.h
+++ b/libcxx/include/__algorithm/copy.h
@@ -10,6 +10,7 @@
 #define _LIBCPP___ALGORITHM_COPY_H
 
 #include <__algorithm/copy_move_common.h>
+#include <__algorithm/for_each_segment.h>
 #include <__algorithm/iterator_operations.h>
 #include <__algorithm/min.h>
 #include <__config>
@@ -44,36 +45,34 @@ struct __copy_loop {
     return std::make_pair(std::move(__first), std::move(__result));
   }
 
-  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
-  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+  template <class _InIter, class _OutIter>
+  struct _CopySegment {
     using _Traits = __segmented_iterator_traits<_InIter>;
-    auto __sfirst = _Traits::__segment(__first);
-    auto __slast  = _Traits::__segment(__last);
-    if (__sfirst == __slast) {
-      auto __iters = std::__copy<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
-      return std::make_pair(__last, std::move(__iters.second));
-    }
 
-    __result = std::__copy<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__sfirst), std::move(__result)).second;
-    ++__sfirst;
-    while (__sfirst != __slast) {
-      __result =
-          std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__end(__sfirst), std::move(__result)).second;
-      ++__sfirst;
+    _OutIter& __result_;
+
+    _LIBCPP_HIDE_FROM_ABI _CopySegment(_OutIter& __result) : __result_(__result) {}
+
+    _LIBCPP_HIDE_FROM_ABI void
+    operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
+      __result_ = std::__copy<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
     }
-    __result =
-        std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__local(__last), std::move(__result)).second;
+  };
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    std::__for_each_segment(__first, __last, _CopySegment<_InIter, _OutIter>(__result));
     return std::make_pair(__last, std::move(__result));
   }
 
   template <class _InIter,
             class _OutIter,
-            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
-  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
     using _Traits = __segmented_iterator_traits<_OutIter>;
     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
 
@@ -98,8 +97,7 @@ struct __copy_loop {
 
 struct __copy_trivial {
   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
-  template <class _In, class _Out,
-            __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
+  template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
   operator()(_In* __first, _In* __last, _Out* __result) const {
     return std::__copy_trivial_impl(__first, __last, __result);
-- 
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