[turbofan] Fix tail call optimization.

src/compiler/schedule.h

 // Copyright 2013 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_SCHEDULE_H_
 #define V8_COMPILER_SCHEDULE_H_
 
 #include <iosfwd>
 
 #include "src/zone-containers.h"
@@ skipping 19 matching lines @@
  public:
   // Possible control nodes that can end a block.
   enum Control {
     kNone,        // Control not initialized yet.
     kGoto,        // Goto a single successor block.
     kCall,        // Call with continuation as first successor, exception
                   // second.
     kBranch,      // Branch if true to first successor, otherwise second.
     kSwitch,      // Table dispatch to one of the successor blocks.
     kDeoptimize,  // Return a value from this method.
+    kTailCall,    // Tail call another method from this method.
     kReturn,      // Return a value from this method.
     kThrow        // Throw an exception.
   };
 
   class Id {
    public:
     int ToInt() const { return static_cast<int>(index_); }
     size_t ToSize() const { return index_; }
     static Id FromSize(size_t index) { return Id(index); }
     static Id FromInt(int index) { return Id(static_cast<size_t>(index)); }
@@ skipping 163 matching lines @@
   void AddBranch(BasicBlock* block, Node* branch, BasicBlock* tblock,
                  BasicBlock* fblock);
 
   // BasicBlock building: add a switch at the end of {block}.
   void AddSwitch(BasicBlock* block, Node* sw, BasicBlock** succ_blocks,
                  size_t succ_count);
 
   // BasicBlock building: add a deoptimize at the end of {block}.
   void AddDeoptimize(BasicBlock* block, Node* input);
 
+  // BasicBlock building: add a tailcall at the end of {block}.
+  void AddTailCall(BasicBlock* block, Node* input);
+
   // BasicBlock building: add a return at the end of {block}.
   void AddReturn(BasicBlock* block, Node* input);
 
   // BasicBlock building: add a throw at the end of {block}.
   void AddThrow(BasicBlock* block, Node* input);
 
   // BasicBlock mutation: insert a branch into the end of {block}.
   void InsertBranch(BasicBlock* block, BasicBlock* end, Node* branch,
                     BasicBlock* tblock, BasicBlock* fblock);
 
@@ skipping 34 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(Schedule);
 };
 
 std::ostream& operator<<(std::ostream&, const Schedule&);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULE_H_