[turbofan] Fix tail call optimization.

src/compiler/scheduler.cc

 // 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.
 
 #include "src/compiler/scheduler.h"
 
 #include <iomanip>
 
 #include "src/base/adapters.h"
 #include "src/bit-vector.h"
@@ skipping 327 matching lines @@
         ConnectBranch(node);
         break;
       case IrOpcode::kSwitch:
         scheduler_->UpdatePlacement(node, Scheduler::kFixed);
         ConnectSwitch(node);
         break;
       case IrOpcode::kDeoptimize:
         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);
         break;
       case IrOpcode::kThrow:
         scheduler_->UpdatePlacement(node, Scheduler::kFixed);
         ConnectThrow(node);
         break;
       case IrOpcode::kCall:
         if (NodeProperties::IsExceptionalCall(node)) {
@@ skipping 122 matching lines @@
     DCHECK_NOT_NULL(block);
     // For all of the merge's control inputs, add a goto at the end to the
     // merge's basic block.
     for (Node* const input : merge->inputs()) {
       BasicBlock* predecessor_block = FindPredecessorBlock(input);
       TraceConnect(merge, predecessor_block, block);
       schedule_->AddGoto(predecessor_block, block);
     }
   }
 
+  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);
     TraceConnect(ret, return_block, NULL);
     schedule_->AddReturn(return_block, ret);
   }
 
   void ConnectDeoptimize(Node* deopt) {
     Node* deoptimize_control = NodeProperties::GetControlInput(deopt);
     BasicBlock* deoptimize_block = FindPredecessorBlock(deoptimize_control);
@@ skipping 1184 matching lines @@
   for (Node* const node : *nodes) {
     schedule_->SetBlockForNode(to, node);
     scheduled_nodes_[to->id().ToSize()].push_back(node);
   }
   nodes->clear();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8