1 files changed, 106 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__pstl/internal/parallel_backend_serial.h b/contrib/llvm-project/libcxx/include/__pstl/internal/parallel_backend_serial.h
new file mode 100644
index 000000000000..dd72222f20ae
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__pstl/internal/parallel_backend_serial.h
@@ -0,0 +1,106 @@
+// -*- 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 _PSTL_PARALLEL_BACKEND_SERIAL_H
+#define _PSTL_PARALLEL_BACKEND_SERIAL_H
+
+#include <__config>
+#include <__memory/allocator.h>
+#include <__pstl/internal/execution_impl.h>
+#include <__utility/forward.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+namespace __pstl
+{
+namespace __serial_backend
+{
+
+template <typename _Tp>
+class __buffer
+{
+    std::allocator<_Tp> __allocator_;
+    _Tp* __ptr_;
+    const std::size_t __buf_size_;
+    __buffer(const __buffer&) = delete;
+    void
+    operator=(const __buffer&) = delete;
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    __buffer(std::size_t __n) : __allocator_(), __ptr_(__allocator_.allocate(__n)), __buf_size_(__n) {}
+
+    _LIBCPP_HIDE_FROM_ABI operator bool() const { return __ptr_ != nullptr; }
+    _LIBCPP_HIDE_FROM_ABI _Tp*
+    get() const
+    {
+        return __ptr_;
+    }
+    _LIBCPP_HIDE_FROM_ABI ~__buffer() { __allocator_.deallocate(__ptr_, __buf_size_); }
+};
+
+template <class _ExecutionPolicy, class _Value, class _Index, typename _RealBody, typename _Reduction>
+_LIBCPP_HIDE_FROM_ABI _Value
+__parallel_reduce(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last,
+                  const _Value& __identity, const _RealBody& __real_body, const _Reduction&)
+{
+    if (__first == __last)
+    {
+        return __identity;
+    }
+    else
+    {
+        return __real_body(__first, __last, __identity);
+    }
+}
+
+template <class _ExecutionPolicy, typename _Index, typename _Tp, typename _Rp, typename _Cp, typename _Sp, typename _Ap>
+_LIBCPP_HIDE_FROM_ABI void
+__parallel_strict_scan(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __n, _Tp __initial,
+                       _Rp __reduce, _Cp __combine, _Sp __scan, _Ap __apex)
+{
+    _Tp __sum = __initial;
+    if (__n)
+        __sum = __combine(__sum, __reduce(_Index(0), __n));
+    __apex(__sum);
+    if (__n)
+        __scan(_Index(0), __n, __initial);
+}
+
+template <class _ExecutionPolicy, class _Index, class _UnaryOp, class _Tp, class _BinaryOp, class _Reduce, class _Scan>
+_LIBCPP_HIDE_FROM_ABI _Tp
+__parallel_transform_scan(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __n, _UnaryOp,
+                          _Tp __init, _BinaryOp, _Reduce, _Scan __scan)
+{
+    return __scan(_Index(0), __n, __init);
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
+_LIBCPP_HIDE_FROM_ABI void
+__parallel_stable_sort(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator __first,
+                       _RandomAccessIterator __last, _Compare __comp, _LeafSort __leaf_sort, std::size_t = 0)
+{
+    __leaf_sort(__first, __last, __comp);
+}
+
+template <class _ExecutionPolicy, typename _F1, typename _F2>
+_LIBCPP_HIDE_FROM_ABI void
+__parallel_invoke(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _F1&& __f1, _F2&& __f2)
+{
+    std::forward<_F1>(__f1)();
+    std::forward<_F2>(__f2)();
+}
+
+} // namespace __serial_backend
+} // namespace __pstl
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif /* _PSTL_PARALLEL_BACKEND_SERIAL_H */