[turbofan] Initial version of branch cloning.

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/platform/elapsed-timer.h"
@@ skipping 515 matching lines @@
     AddReducer(data, &graph_reducer, &common_reducer);
     graph_reducer.ReduceGraph();
   }
 };
 
 
 struct ControlFlowOptimizationPhase {
   static const char* phase_name() { return "control flow optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
+    SourcePositionTable::Scope pos(data->source_positions(),
+                                   SourcePosition::Unknown());
     ControlFlowOptimizer optimizer(data->jsgraph(), temp_zone);
     optimizer.Optimize();
   }
 };
 
 
 struct ChangeLoweringPhase {
   static const char* phase_name() { return "change lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
@@ skipping 404 matching lines @@
       Run<OsrDeconstructionPhase>();
       if (info()->bailout_reason() != kNoReason) return Handle<Code>::null();
       RunPrintAndVerify("OSR deconstruction");
     }
 
     // Lower simplified operators and insert changes.
     Run<SimplifiedLoweringPhase>();
     RunPrintAndVerify("Lowered simplified");
 
     // Optimize control flow.
-    if (FLAG_turbo_switch) {
+    if (FLAG_turbo_cf_optimization) {
       Run<ControlFlowOptimizationPhase>();
       RunPrintAndVerify("Control flow optimized");
     }
 
     // Lower changes that have been inserted before.
     Run<ChangeLoweringPhase>();
     // // TODO(jarin, rossberg): Remove UNTYPED once machine typing works.
     RunPrintAndVerify("Lowered changes", true);
 
     Run<LateControlReductionPhase>();
@@ skipping 224 matching lines @@
 
   if (FLAG_trace_turbo && !data->MayHaveUnverifiableGraph()) {
     TurboCfgFile tcf(data->isolate());
     tcf << AsC1VAllocator("CodeGen", data->register_allocator());
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8