[turbofan] Better and more sane support for tail calls

src/compiler/js-intrinsic-lowering.h

 // 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_INTRINSIC_LOWERING_H_
 #define V8_COMPILER_JS_INTRINSIC_LOWERING_H_
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph-reducer.h"
 
@@ skipping 52 matching lines @@
   Reduction ReduceGetCallerJSFunction(Node* node);
   Reduction ReduceThrowNotDateError(Node* node);
   Reduction ReduceToInteger(Node* node);
   Reduction ReduceToLength(Node* node);
   Reduction ReduceToName(Node* node);
   Reduction ReduceToNumber(Node* node);
   Reduction ReduceToObject(Node* node);
   Reduction ReduceToPrimitive(Node* node);
   Reduction ReduceToString(Node* node);
   Reduction ReduceCall(Node* node);
+  Reduction ReduceTailCall(Node* node);
 
   Reduction Change(Node* node, const Operator* op);
   Reduction Change(Node* node, const Operator* op, Node* a, Node* b);
   Reduction Change(Node* node, const Operator* op, Node* a, Node* b, Node* c);
   Reduction Change(Node* node, const Operator* op, Node* a, Node* b, Node* c,
                    Node* d);
   Reduction ChangeToUndefined(Node* node, Node* effect = nullptr);
 
   Graph* graph() const;
   JSGraph* jsgraph() const { return jsgraph_; }
   Isolate* isolate() const;
   CommonOperatorBuilder* common() const;
   JSOperatorBuilder* javascript() const;
   MachineOperatorBuilder* machine() const;
   SimplifiedOperatorBuilder* simplified() const;
   DeoptimizationMode mode() const { return mode_; }
   TypeCache const& type_cache() const { return type_cache_; }
 
   JSGraph* const jsgraph_;
   DeoptimizationMode const mode_;
   TypeCache const& type_cache_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_INTRINSIC_LOWERING_H_