[turbofan] Implement simplistic checkpoint reducer.

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"
 #include "src/base/platform/elapsed-timer.h"
 #include "src/compiler/ast-graph-builder.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/basic-block-instrumentor.h"
 #include "src/compiler/branch-elimination.h"
 #include "src/compiler/bytecode-graph-builder.h"
+#include "src/compiler/checkpoint-elimination.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/common-operator-reducer.h"
 #include "src/compiler/control-flow-optimizer.h"
 #include "src/compiler/dead-code-elimination.h"
 #include "src/compiler/effect-control-linearizer.h"
 #include "src/compiler/escape-analysis-reducer.h"
 #include "src/compiler/escape-analysis.h"
 #include "src/compiler/frame-elider.h"
 #include "src/compiler/graph-replay.h"
 #include "src/compiler/graph-trimmer.h"
@@ skipping 857 matching lines @@
     }
     JSTypedLowering typed_lowering(&graph_reducer, data->info()->dependencies(),
                                    typed_lowering_flags, data->jsgraph(),
                                    temp_zone);
     JSIntrinsicLowering intrinsic_lowering(
         &graph_reducer, data->jsgraph(),
         data->info()->is_deoptimization_enabled()
             ? JSIntrinsicLowering::kDeoptimizationEnabled
             : JSIntrinsicLowering::kDeoptimizationDisabled);
     SimplifiedOperatorReducer simple_reducer(data->jsgraph());
+    CheckpointElimination checkpoint_elimination(&graph_reducer);
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->common(), data->machine());
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &builtin_reducer);
     if (data->info()->is_deoptimization_enabled()) {
       AddReducer(data, &graph_reducer, &create_lowering);
     }
     AddReducer(data, &graph_reducer, &typed_lowering);
     AddReducer(data, &graph_reducer, &intrinsic_lowering);
     AddReducer(data, &graph_reducer, &load_elimination);
     AddReducer(data, &graph_reducer, &simple_reducer);
+    AddReducer(data, &graph_reducer, &checkpoint_elimination);
     AddReducer(data, &graph_reducer, &common_reducer);
     graph_reducer.ReduceGraph();
   }
 };
 
 
 struct BranchEliminationPhase {
   static const char* phase_name() { return "branch condition elimination"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
@@ skipping 881 matching lines @@
   data->DeleteRegisterAllocationZone();
 }
 
 CompilationInfo* PipelineImpl::info() const { return data_->info(); }
 
 Isolate* PipelineImpl::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8