[turbofan] Fix tail call optimization.

src/compiler/scheduler.cc

Index: src/compiler/scheduler.cc
diff --git a/src/compiler/scheduler.cc b/src/compiler/scheduler.cc
index 3a2af0234614794baed8bd80677891aac9432847..066b4a13776444b54ca5aea936f9bcdd3894266b 100644
--- a/src/compiler/scheduler.cc
+++ b/src/compiler/scheduler.cc
@@ -345,6 +345,10 @@ class CFGBuilder : public ZoneObject {
         scheduler_->UpdatePlacement(node, Scheduler::kFixed);
         ConnectDeoptimize(node);
         break;
+      case IrOpcode::kTailCall:
+        scheduler_->UpdatePlacement(node, Scheduler::kFixed);
+        ConnectTailCall(node);
+        break;
       case IrOpcode::kReturn:
         scheduler_->UpdatePlacement(node, Scheduler::kFixed);
         ConnectReturn(node);
@@ -487,6 +491,13 @@ class CFGBuilder : public ZoneObject {
     }
   }
 
+  void ConnectTailCall(Node* call) {
+    Node* call_control = NodeProperties::GetControlInput(call);
+    BasicBlock* call_block = FindPredecessorBlock(call_control);
+    TraceConnect(call, call_block, NULL);
+    schedule_->AddTailCall(call_block, call);
+  }
+
   void ConnectReturn(Node* ret) {
     Node* return_control = NodeProperties::GetControlInput(ret);
     BasicBlock* return_block = FindPredecessorBlock(return_control);