[libcxx-commits] [libcxx] 68ee014 - [libc++][PSTL] Implement std::for_each{, _n}

Nikolas Klauser via libcxx-commits libcxx-commits at lists.llvm.org
Sun Apr 30 13:27:26 PDT 2023


Author: Nikolas Klauser
Date: 2023-04-30T13:27:20-07:00
New Revision: 68ee014b15d3c936b8adb333d6a3f973f071f2cf

URL: https://github.com/llvm/llvm-project/commit/68ee014b15d3c936b8adb333d6a3f973f071f2cf
DIFF: https://github.com/llvm/llvm-project/commit/68ee014b15d3c936b8adb333d6a3f973f071f2cf.diff

LOG: [libc++][PSTL] Implement std::for_each{, _n}

Reviewed By: ldionne, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D149381

Added: 
    libcxx/include/__algorithm/pstl_for_each.h
    libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each.pass.cpp
    libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each_n.pass.cpp

Modified: 
    libcxx/include/CMakeLists.txt
    libcxx/include/__pstl/internal/glue_algorithm_defs.h
    libcxx/include/__pstl/internal/glue_algorithm_impl.h
    libcxx/include/algorithm
    libcxx/test/support/test_execution_policies.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index b9cb69b14b73f..61b914130fa60 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -70,6 +70,7 @@ set(files
   __algorithm/pop_heap.h
   __algorithm/prev_permutation.h
   __algorithm/pstl_any_all_none_of.h
+  __algorithm/pstl_for_each.h
   __algorithm/push_heap.h
   __algorithm/ranges_adjacent_find.h
   __algorithm/ranges_all_of.h

diff  --git a/libcxx/include/__algorithm/pstl_for_each.h b/libcxx/include/__algorithm/pstl_for_each.h
new file mode 100644
index 0000000000000..48bbeff2fc5d7
--- /dev/null
+++ b/libcxx/include/__algorithm/pstl_for_each.h
@@ -0,0 +1,73 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_FOR_EACH_H
+#define _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H
+
+#include <__algorithm/for_each.h>
+#include <__algorithm/for_each_n.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__pstl/internal/parallel_backend.h>
+#include <__pstl/internal/unseq_backend_simd.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Function,
+          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI void
+for_each(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Function __func) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+    std::__terminate_on_exception([&] {
+      __pstl::__par_backend::__parallel_for(
+          {},
+          __policy,
+          __first,
+          __last,
+          [&__policy, __func](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
+            std::for_each(std::__remove_parallel_policy(__policy), __brick_first, __brick_last, __func);
+          });
+    });
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+    __pstl::__unseq_backend::__simd_walk_1(__first, __last - __first, __func);
+  } else {
+    std::for_each(__first, __last, __func);
+  }
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Size,
+          class _Function,
+          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI void
+for_each_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __size, _Function __func) {
+  if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+    std::for_each(__policy, __first, __first + __size, __func);
+  } else {
+    std::for_each_n(__first, __size, __func);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H

diff  --git a/libcxx/include/__pstl/internal/glue_algorithm_defs.h b/libcxx/include/__pstl/internal/glue_algorithm_defs.h
index f75bf28da3904..06453c0bd9d30 100644
--- a/libcxx/include/__pstl/internal/glue_algorithm_defs.h
+++ b/libcxx/include/__pstl/internal/glue_algorithm_defs.h
@@ -20,16 +20,6 @@ _PSTL_HIDE_FROM_ABI_PUSH
 
 namespace std {
 
-// [alg.foreach]
-
-template <class _ExecutionPolicy, class _ForwardIterator, class _Function>
-__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
-for_each(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Function __f);
-
-template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Function>
-__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
-for_each_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, _Function __f);
-
 // [alg.find]
 
 template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>

diff  --git a/libcxx/include/__pstl/internal/glue_algorithm_impl.h b/libcxx/include/__pstl/internal/glue_algorithm_impl.h
index f09b3e977b93a..e3aa2b4b30c4f 100644
--- a/libcxx/include/__pstl/internal/glue_algorithm_impl.h
+++ b/libcxx/include/__pstl/internal/glue_algorithm_impl.h
@@ -25,25 +25,6 @@ _PSTL_HIDE_FROM_ABI_PUSH
 
 namespace std {
 
-// [alg.foreach]
-
-template <class _ExecutionPolicy, class _ForwardIterator, class _Function>
-__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
-for_each(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Function __f) {
-  auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
-
-  __pstl::__internal::__pattern_walk1(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __f);
-}
-
-template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Function>
-__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
-for_each_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, _Function __f) {
-  auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
-
-  return __pstl::__internal::__pattern_walk1_n(
-      __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n, __f);
-}
-
 // [alg.find]
 
 template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>

diff  --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index d8d38b875c1fb..611c639c3b6c2 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -1910,6 +1910,7 @@ template <class BidirectionalIterator, class Compare>
 
 #ifdef _LIBCPP_HAS_PARALLEL_ALGORITHMS
 #  include <__algorithm/pstl_any_all_none_of.h>
+#  include <__algorithm/pstl_for_each.h>
 #endif
 
 // standard-mandated includes

diff  --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each.pass.cpp
new file mode 100644
index 0000000000000..49d3bd16dc021
--- /dev/null
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each.pass.cpp
@@ -0,0 +1,65 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 ForwardIterator, class Function>
+//   void for_each(ExecutionPolicy&& exec,
+//                 ForwardIterator first, ForwardIterator last,
+//                 Function f);
+
+#include <algorithm>
+#include <atomic>
+#include <cassert>
+#include <vector>
+
+#include "test_macros.h"
+#include "test_execution_policies.h"
+#include "test_iterators.h"
+
+EXECUTION_POLICY_SFINAE_TEST(for_each);
+
+static_assert(sfinae_test_for_each<int, int*, int*, bool (*)(int)>);
+static_assert(!sfinae_test_for_each<std::execution::parallel_policy, int*, int*, bool (*)(int)>);
+
+template <class Iter>
+struct Test {
+  template <class Policy>
+  void operator()(Policy&& policy) {
+    int sizes[] = {0, 1, 2, 100};
+    for (auto size : sizes) {
+      std::vector<int> a(size);
+      std::vector<Bool> called(size);
+      std::for_each(policy, Iter(std::data(a)), Iter(std::data(a) + std::size(a)), [&](int& v) {
+        assert(!called[&v - a.data()]);
+        called[&v - a.data()] = true;
+      });
+      assert(std::all_of(std::begin(called), std::end(called), [](bool b) { return b; }));
+    }
+  }
+};
+
+int main(int, char**) {
+  types::for_each(types::forward_iterator_list<int*>{}, TestIteratorWithPolicies<Test>{});
+
+#ifndef TEST_HAS_NO_EXCEPTIONS
+  std::set_terminate(terminate_successful);
+  int a[] = {1, 2};
+  try {
+    std::for_each(std::execution::par, std::begin(a), std::end(a), [](int) { throw int{}; });
+  } catch (int) {
+    assert(false);
+  }
+#endif
+
+  return 0;
+}

diff  --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each_n.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each_n.pass.cpp
new file mode 100644
index 0000000000000..f6588af1225c2
--- /dev/null
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/pstl.for_each_n.pass.cpp
@@ -0,0 +1,65 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 ForwardIterator, class Function>
+//   void for_each(ExecutionPolicy&& exec,
+//                 ForwardIterator first, ForwardIterator last,
+//                 Function f);
+
+#include <algorithm>
+#include <atomic>
+#include <cassert>
+#include <vector>
+
+#include "test_macros.h"
+#include "test_execution_policies.h"
+#include "test_iterators.h"
+
+EXECUTION_POLICY_SFINAE_TEST(for_each);
+
+static_assert(sfinae_test_for_each<int, int*, int*, bool (*)(int)>);
+static_assert(!sfinae_test_for_each<std::execution::parallel_policy, int*, int*, bool (*)(int)>);
+
+template <class Iter>
+struct Test {
+  template <class Policy>
+  void operator()(Policy&& policy) {
+    int sizes[] = {0, 1, 2, 100};
+    for (auto size : sizes) {
+      std::vector<int> a(size);
+      std::vector<Bool> called(size);
+      std::for_each_n(policy, Iter(std::data(a)), std::size(a), [&](int& v) {
+        assert(!called[&v - a.data()]);
+        called[&v - a.data()] = true;
+      });
+      assert(std::all_of(std::begin(called), std::end(called), [](bool b) { return b; }));
+    }
+  }
+};
+
+int main(int, char**) {
+  types::for_each(types::forward_iterator_list<int*>{}, TestIteratorWithPolicies<Test>{});
+
+#ifndef TEST_HAS_NO_EXCEPTIONS
+  std::set_terminate(terminate_successful);
+  int a[] = {1, 2};
+  try {
+    std::for_each_n(std::execution::par, std::data(a), std::size(a), [](int) { throw int{}; });
+  } catch (int) {
+    assert(false);
+  }
+#endif
+
+  return 0;
+}

diff  --git a/libcxx/test/support/test_execution_policies.h b/libcxx/test/support/test_execution_policies.h
index 5d106b13c1c05..d9180fb913bcc 100644
--- a/libcxx/test/support/test_execution_policies.h
+++ b/libcxx/test/support/test_execution_policies.h
@@ -47,6 +47,16 @@ struct TestIteratorWithPolicies {
   }
 };
 
+struct Bool {
+  bool b_;
+  Bool() = default;
+  Bool(bool b) : b_(b) {}
+
+  operator bool&() {
+    return b_;
+  }
+};
+
 [[noreturn]] inline void terminate_successful() { std::exit(0); }
 
 #endif // TEST_SUPPORT_TEST_EXECUTION_POLICIES


        


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