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diff --git a/deps/v8/src/compiler/turboshaft/reducer-traits.h b/deps/v8/src/compiler/turboshaft/reducer-traits.h
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+++ b/deps/v8/src/compiler/turboshaft/reducer-traits.h
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+// Copyright 2022 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_COMPILER_TURBOSHAFT_REDUCER_TRAITS_H_
+#define V8_COMPILER_TURBOSHAFT_REDUCER_TRAITS_H_
+
+#include <type_traits>
+
+namespace v8::internal::compiler::turboshaft {
+
+template <class Assembler, template <class> class... Reducers>
+class ReducerStack;
+
+template <typename Next>
+class ReducerBase;
+
+// is_same_reducer compares two reducers.
+template <template <typename> typename T, template <typename> typename U>
+struct is_same_reducer : public std::bool_constant<false> {};
+
+template <template <typename> typename Reducer>
+struct is_same_reducer<Reducer, Reducer> : public std::bool_constant<true> {};
+
+template <template <typename> typename...>
+struct reducer_list {};
+// Converts a ReducerStack {Next} to a reducer_list<>;
+template <typename Next>
+struct reducer_stack_to_list;
+template <typename A, template <typename> typename... Reducers>
+struct reducer_stack_to_list<ReducerStack<A, Reducers...>> {
+  using type = reducer_list<Reducers...>;
+};
+
+// Checks if a reducer_list<> {RL} contains reducer {R}.
+template <typename RL, template <typename> typename R>
+struct reducer_list_contains;
+template <template <typename> typename R, template <typename> typename Head,
+          template <typename> typename... Tail>
+struct reducer_list_contains<reducer_list<Head, Tail...>, R> {
+  static constexpr bool value =
+      is_same_reducer<Head, R>::value ||
+      reducer_list_contains<reducer_list<Tail...>, R>::value;
+};
+template <template <typename> typename R>
+struct reducer_list_contains<reducer_list<>, R>
+    : public std::bool_constant<false> {};
+
+// Checks if a reducer_list<> {RL} starts with reducer {R}.
+template <typename RL, template <typename> typename R>
+struct reducer_list_starts_with;
+template <template <typename> typename R, template <typename> typename Head,
+          template <typename> typename... Tail>
+struct reducer_list_starts_with<reducer_list<Head, Tail...>, R>
+    : public std::bool_constant<is_same_reducer<Head, R>::value> {};
+template <template <typename> typename R>
+struct reducer_list_starts_with<reducer_list<>, R>
+    : public std::bool_constant<false> {};
+
+// Check if the {Next} ReducerStack contains {Reducer}.
+template <typename Next, template <typename> typename Reducer>
+struct next_contains_reducer {
+  using list = typename reducer_stack_to_list<Next>::type;
+  static constexpr bool value = reducer_list_contains<list, Reducer>::value;
+};
+
+// Check if in the {Next} ReducerStack, {Reducer} comes next.
+template <typename Next, template <typename> typename Reducer>
+struct next_reducer_is {
+  using list = typename reducer_stack_to_list<Next>::type;
+  static constexpr bool value = reducer_list_starts_with<list, Reducer>::value;
+};
+
+// Check if {Next} is the bottom of the ReducerStack.
+template <typename Next>
+struct next_is_bottom_of_assembler_stack
+    : public next_reducer_is<Next, ReducerBase> {};
+
+}  // namespace v8::internal::compiler::turboshaft
+
+#endif  // V8_COMPILER_TURBOSHAFT_REDUCER_TRAITS_H_