Revert "[libc++][PSTL] Implement std::copy{,_n}"

This reverts commit b049fc0481bc387f57fd61da7239f85ef91096c1.

The wrong patch was landed.

7 files changed, 44 insertions, 265 deletions

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index d94601e59eae..ead9693b5f7d 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -79,7 +79,6 @@ set(files
   __algorithm/pstl_backends/cpu_backends/for_each.h
   __algorithm/pstl_backends/cpu_backends/serial.h
   __algorithm/pstl_backends/cpu_backends/transform.h
-  __algorithm/pstl_copy.h
   __algorithm/pstl_fill.h
   __algorithm/pstl_find.h
   __algorithm/pstl_for_each.h
diff --git a/libcxx/include/__algorithm/pstl_copy.h b/libcxx/include/__algorithm/pstl_copy.h
deleted file mode 100644
index 2d331d29a5d1..000000000000
--- a/libcxx/include/__algorithm/pstl_copy.h
+++ /dev/null
@@ -1,57 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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___ALGORITHM_PSTL_COPY_H
-#define _LIBCPP___ALGORITHM_PSTL_COPY_H
-
-#include <__algorithm/copy_n.h>
-#include <__algorithm/pstl_transform.h>
-#include <__config>
-#include <__functional/identity.h>
-#include <__iterator/iterator_traits.h>
-#include <__type_traits/is_constant_evaluated.h>
-#include <__type_traits/is_execution_policy.h>
-#include <__type_traits/is_trivially_copyable.h>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
-
-_LIBCPP_BEGIN_NAMESPACE_STD
-
-// TODO: Use the std::copy/move shenanigans to forward to std::memmove
-
-template <class _ExecutionPolicy,
-          class _ForwardIterator,
-          class _ForwardOutIterator,
-          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
-_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
-copy(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
-  return std::transform(__policy, __first, __last, __result, __identity());
-}
-
-template <class _ExecutionPolicy,
-          class _ForwardIterator,
-          class _ForwardOutIterator,
-          class _Size,
-          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
-_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
-copy_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __result) {
-  if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value)
-    return std::copy(__policy, __first, __first + __n, __result);
-  else
-    return std::copy_n(__first, __n, __result);
-}
-
-_LIBCPP_END_NAMESPACE_STD
-
-#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
-
-#endif // _LIBCPP___ALGORITHM_PSTL_COPY_H
diff --git a/libcxx/include/__pstl/internal/glue_algorithm_defs.h b/libcxx/include/__pstl/internal/glue_algorithm_defs.h
index 00458d5ffbbd..de4501e56b2c 100644
--- a/libcxx/include/__pstl/internal/glue_algorithm_defs.h
+++ b/libcxx/include/__pstl/internal/glue_algorithm_defs.h
@@ -112,6 +112,14 @@ __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardItera
 
 // [alg.copy]
 
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy_n(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _Size __n, _ForwardIterator2 __result);
+
 template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
 __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
 copy_if(_ExecutionPolicy&& __exec,
diff --git a/libcxx/include/__pstl/internal/glue_algorithm_impl.h b/libcxx/include/__pstl/internal/glue_algorithm_impl.h
index 942ea0dea50b..bae5efa7d057 100644
--- a/libcxx/include/__pstl/internal/glue_algorithm_impl.h
+++ b/libcxx/include/__pstl/internal/glue_algorithm_impl.h
@@ -178,6 +178,42 @@ __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardItera
 
 // [alg.copy]
 
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result) {
+  auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+  using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+  return __pstl::__internal::__pattern_walk2_brick(
+      __dispatch_tag,
+      std::forward<_ExecutionPolicy>(__exec),
+      __first,
+      __last,
+      __result,
+      [](_ForwardIterator1 __begin, _ForwardIterator1 __end, _ForwardIterator2 __res) {
+        return __pstl::__internal::__brick_copy(__begin, __end, __res, __is_vector{});
+      });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy_n(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _Size __n, _ForwardIterator2 __result) {
+  auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+  using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+  return __pstl::__internal::__pattern_walk2_brick_n(
+      __dispatch_tag,
+      std::forward<_ExecutionPolicy>(__exec),
+      __first,
+      __n,
+      __result,
+      [](_ForwardIterator1 __begin, _Size __sz, _ForwardIterator2 __res) {
+        return __pstl::__internal::__brick_copy_n(__begin, __sz, __res, __is_vector{});
+      });
+}
+
 template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
 __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
 copy_if(_ExecutionPolicy&& __exec,
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 8c0498a04ac7..18a89eb1a4dc 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -1789,7 +1789,6 @@ template <class BidirectionalIterator, class Compare>
 #include <__algorithm/pop_heap.h>
 #include <__algorithm/prev_permutation.h>
 #include <__algorithm/pstl_any_all_none_of.h>
-#include <__algorithm/pstl_copy.h>
 #include <__algorithm/pstl_fill.h>
 #include <__algorithm/pstl_find.h>
 #include <__algorithm/pstl_for_each.h>
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/pstl.copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/pstl.copy.pass.cpp
deleted file mode 100644
index bee1ef9bcec3..000000000000
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/pstl.copy.pass.cpp
+++ /dev/null
@@ -1,104 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14
-
-// REQUIRES: with-pstl
-
-// <algorithm>
-
-// template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2>
-//   ForwardIterator2 copy(ExecutionPolicy&& policy,
-//                         ForwardIterator1 first, ForwardIterator1 last,
-//                         ForwardIterator2 result);
-
-#include <algorithm>
-#include <vector>
-
-#include "test_macros.h"
-#include "test_execution_policies.h"
-#include "test_iterators.h"
-
-EXECUTION_POLICY_SFINAE_TEST(copy);
-
-static_assert(sfinae_test_copy<int, int*, int*, bool (*)(int)>);
-static_assert(!sfinae_test_copy<std::execution::parallel_policy, int*, int*, int>);
-
-template <class Iter1, class Iter2>
-struct TestInt {
-  template <class Policy>
-  void operator()(Policy&& policy) {
-    // simple test
-    for (const int size : {0, 1, 2, 100, 350}) {
-      std::vector<int> a(size);
-      for (int i = 0; i != size; ++i)
-        a[i] = i + 1;
-
-      std::vector<int> out(std::size(a));
-      decltype(auto) ret =
-          std::copy(policy, Iter1(std::data(a)), Iter1(std::data(a) + std::size(a)), Iter2(std::data(out)));
-      static_assert(std::is_same_v<decltype(ret), Iter2>);
-      assert(base(ret) == std::data(out) + std::size(out));
-      for (int i = 0; i != size; ++i)
-        assert(out[i] == i + 1);
-    }
-  }
-};
-
-struct CopiedToTester {
-  bool copied_to   = false;
-  CopiedToTester() = default;
-  CopiedToTester(const CopiedToTester&) {}
-  CopiedToTester& operator=(const CopiedToTester&) {
-    assert(!copied_to);
-    copied_to = true;
-    return *this;
-  }
-  ~CopiedToTester() = default;
-};
-
-template <class Iter1, class Iter2>
-struct TestNonTrivial {
-  template <class Policy>
-  void operator()(Policy&& policy) {
-    // simple test
-    for (const int size : {0, 1, 2, 100, 350}) {
-      std::vector<CopiedToTester> a(size);
-
-      std::vector<CopiedToTester> out(std::size(a));
-      auto ret = std::copy(policy, Iter1(std::data(a)), Iter1(std::data(a) + std::size(a)), Iter2(std::data(out)));
-      assert(base(ret) == std::data(out) + std::size(out));
-      assert(std::all_of(std::begin(out), std::end(out), [](CopiedToTester& t) { return t.copied_to; }));
-      assert(std::none_of(std::begin(a), std::end(a), [](CopiedToTester& t) { return t.copied_to; }));
-    }
-  }
-};
-
-struct TestIteratorsNonTrivial {
-  template <class Iter2>
-  void operator()() {}
-};
-
-int main(int, char**) {
-  types::for_each(types::forward_iterator_list<int*>{}, types::apply_type_identity{[](auto v) {
-                    using Iter = typename decltype(v)::type;
-                    types::for_each(
-                        types::forward_iterator_list<int*>{},
-                        TestIteratorWithPolicies< types::partial_instantiation<TestInt, Iter>::template apply>{});
-                  }});
-
-  types::for_each(
-      types::forward_iterator_list<CopiedToTester*>{}, types::apply_type_identity{[](auto v) {
-        using Iter = typename decltype(v)::type;
-        types::for_each(
-            types::forward_iterator_list<CopiedToTester*>{},
-            TestIteratorWithPolicies< types::partial_instantiation<TestNonTrivial, Iter>::template apply>{});
-      }});
-
-  return 0;
-}
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/pstl.copy_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/pstl.copy_n.pass.cpp
deleted file mode 100644
index 128108ac1381..000000000000
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/pstl.copy_n.pass.cpp
+++ /dev/null
@@ -1,102 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14
-
-// REQUIRES: with-pstl
-
-// <algorithm>
-
-// template<class ExecutionPolicy, class ForwardIterator1, class Size, class ForwardIterator2>
-//   ForwardIterator2 copy_n(ExecutionPolicy&& exec,
-//                           ForwardIterator1 first, Size n,
-//                           ForwardIterator2 result);
-
-#include <algorithm>
-#include <vector>
-
-#include "test_macros.h"
-#include "test_execution_policies.h"
-#include "test_iterators.h"
-
-EXECUTION_POLICY_SFINAE_TEST(copy_n);
-
-static_assert(sfinae_test_copy_n<int, int*, int*, bool (*)(int)>);
-static_assert(!sfinae_test_copy_n<std::execution::parallel_policy, int*, int*, int>);
-
-template <class Iter1, class Iter2>
-struct TestInt {
-  template <class Policy>
-  void operator()(Policy&& policy) {
-    // simple test
-    for (const int size : {0, 1, 2, 100, 350}) {
-      std::vector<int> a(size);
-      for (int i = 0; i != size; ++i)
-        a[i] = i + 1;
-
-      std::vector<int> out(std::size(a));
-      decltype(auto) ret = std::copy_n(policy, Iter1(std::data(a)), std::size(a), Iter2(std::data(out)));
-      static_assert(std::is_same_v<decltype(ret), Iter2>);
-      assert(base(ret) == std::data(out) + std::size(out));
-      for (int i = 0; i != size; ++i)
-        assert(out[i] == i + 1);
-    }
-  }
-};
-
-struct TestIteratorsInt {
-  template <class Iter2>
-  void operator()() {
-    types::for_each(types::forward_iterator_list<int*>{},
-                    TestIteratorWithPolicies<types::partial_instantiation<TestInt, Iter2>::template apply>{});
-  }
-};
-
-struct CopiedToTester {
-  bool copied_to = false;
-  CopiedToTester() = default;
-  CopiedToTester(const CopiedToTester&) {}
-  CopiedToTester& operator=(const CopiedToTester&) {
-    assert(!copied_to);
-    copied_to = true;
-    return *this;
-  }
-  ~CopiedToTester() = default;
-};
-
-template <class Iter1, class Iter2>
-struct TestNonTrivial {
-  template <class Policy>
-  void operator()(Policy&& policy) {
-    // simple test
-    for (const int size : {0, 1, 2, 100, 350}) {
-      std::vector<CopiedToTester> a(size);
-
-      std::vector<CopiedToTester> out(std::size(a));
-      auto ret = std::copy_n(policy, Iter1(std::data(a)), std::size(a), Iter2(std::data(out)));
-      assert(base(ret) == std::data(out) + std::size(out));
-      assert(std::all_of(std::begin(out), std::end(out), [](CopiedToTester& t) { return t.copied_to; }));
-      assert(std::none_of(std::begin(a), std::end(a), [](CopiedToTester& t) { return t.copied_to; }));
-    }
-  }
-};
-
-struct TestIteratorsNonTrivial {
-  template <class Iter2>
-  void operator()() {
-    types::for_each(types::forward_iterator_list<CopiedToTester*>{},
-                    TestIteratorWithPolicies<types::partial_instantiation<TestNonTrivial, Iter2>::template apply>{});
-  }
-};
-
-int main(int, char**) {
-  types::for_each(types::forward_iterator_list<int*>{}, TestIteratorsInt{});
-  types::for_each(types::forward_iterator_list<CopiedToTester*>{}, TestIteratorsNonTrivial{});
-
-  return 0;
-}