[turbofan] Enable tail calls for %_CallFunction.

src/compiler/pipeline.cc

 // Copyright 2014 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/pipeline.h"
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
 #include "src/base/adapters.h"
@@ skipping 685 matching lines @@
                                          data->common(), data->machine());
     JSGenericLowering generic_lowering(data->info()->is_typing_enabled(),
                                        data->jsgraph());
     SelectLowering select_lowering(data->jsgraph()->graph(),
                                    data->jsgraph()->common());
     TailCallOptimization tco(data->common(), data->graph());
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &common_reducer);
     AddReducer(data, &graph_reducer, &generic_lowering);
     AddReducer(data, &graph_reducer, &select_lowering);
-    // TODO(turbofan): TCO is currently limited to stubs.
-    if (data->info()->IsStub()) AddReducer(data, &graph_reducer, &tco);
+    AddReducer(data, &graph_reducer, &tco);
     graph_reducer.ReduceGraph();
   }
 };
 
 
 struct ComputeSchedulePhase {
   static const char* phase_name() { return "scheduling"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     Schedule* schedule = Scheduler::ComputeSchedule(
@@ skipping 638 matching lines @@
     tcf << AsC1VRegisterAllocationData("CodeGen",
                                        data->register_allocation_data());
   }
 
   data->DeleteRegisterAllocationZone();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8