[turbofan] Fix tail call optimization.

src/compiler/schedule.cc

Index: src/compiler/schedule.cc
diff --git a/src/compiler/schedule.cc b/src/compiler/schedule.cc
index f30e5f61ceb9d944a8afdbe0c16ba2a5822f4a62..adb80a7b081b7c3ceba52752f589d669e25241bc 100644
--- a/src/compiler/schedule.cc
+++ b/src/compiler/schedule.cc
@@ -108,6 +108,8 @@ std::ostream& operator<<(std::ostream& os, const BasicBlock::Control& c) {
       return os << "switch";
     case BasicBlock::kDeoptimize:
       return os << "deoptimize";
+    case BasicBlock::kTailCall:
+      return os << "tailcall";
     case BasicBlock::kReturn:
       return os << "return";
     case BasicBlock::kThrow:
@@ -233,6 +235,14 @@ void Schedule::AddSwitch(BasicBlock* block, Node* sw, BasicBlock** succ_blocks,
 }
 
 
+void Schedule::AddTailCall(BasicBlock* block, Node* input) {
+  DCHECK_EQ(BasicBlock::kNone, block->control());
+  block->set_control(BasicBlock::kTailCall);
+  SetControlInput(block, input);
+  if (block != end()) AddSuccessor(block, end());
+}
+
+
 void Schedule::AddReturn(BasicBlock* block, Node* input) {
   DCHECK_EQ(BasicBlock::kNone, block->control());
   block->set_control(BasicBlock::kReturn);