1 files changed, 45 insertions, 0 deletions

diff --git a/contrib/llvm-project/libcxx/include/__algorithm/pstl_frontend_dispatch.h b/contrib/llvm-project/libcxx/include/__algorithm/pstl_frontend_dispatch.h
new file mode 100644
index 000000000000..dc49f3e5163a
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__algorithm/pstl_frontend_dispatch.h
@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_FRONTEND_DISPATCH
+#define _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH
+
+#include <__config>
+#include <__type_traits/is_callable.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#  define _LIBCPP_PSTL_CUSTOMIZATION_POINT(name)                                                                       \
+    [](auto&&... __args) -> decltype(std::name<_RawPolicy>(typename __select_backend<_RawPolicy>::type{},              \
+                                                           std::forward<decltype(__args)>(__args)...)) {               \
+      return std::name<_RawPolicy>(                                                                                    \
+          typename __select_backend<_RawPolicy>::type{}, std::forward<decltype(__args)>(__args)...);                   \
+    }
+
+template <class _SpecializedImpl, class _GenericImpl, class... _Args>
+_LIBCPP_HIDE_FROM_ABI decltype(auto)
+__pstl_frontend_dispatch(_SpecializedImpl __specialized_impl, _GenericImpl __generic_impl, _Args&&... __args) {
+  if constexpr (__is_callable<_SpecializedImpl, _Args...>::value) {
+    return __specialized_impl(std::forward<_Args>(__args)...);
+  } else {
+    return __generic_impl(std::forward<_Args>(__args)...);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH