[turbofan] Introduce JSCallReducer to strength reduce JSCallFunction nodes.

src/compiler/js-call-reducer.h

Index: src/compiler/js-call-reducer.h
diff --git a/src/compiler/js-call-reducer.h b/src/compiler/js-call-reducer.h
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+// Copyright 2015 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_JS_CALL_REDUCER_H_
+#define V8_COMPILER_JS_CALL_REDUCER_H_
+
+#include "src/compiler/graph-reducer.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// Forward declarations.
+class JSGraph;
+class JSOperatorBuilder;
+
+
+// Performs strength reduction on {JSCallFunction} nodes, which might allow
+// inlining or other optimizations to be performed afterwards.
+class JSCallReducer final : public Reducer {
+ public:
+  explicit JSCallReducer(JSGraph* jsgraph) : jsgraph_(jsgraph) {}
+
+  Reduction Reduce(Node* node) final;
+
+ private:
+  Reduction ReduceFunctionPrototypeApply(Node* node);
+  Reduction ReduceFunctionPrototypeCall(Node* node);
+
+  Graph* graph() const;
+  JSGraph* jsgraph() const { return jsgraph_; }
+  Isolate* isolate() const;
+  JSOperatorBuilder* javascript() const;
+
+  JSGraph* const jsgraph_;
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_JS_CALL_REDUCER_H_