[turbofan] always run value numbering last to patch unpredictable reductions

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 <memory>
 #include <sstream>
 
@@ skipping 1023 matching lines @@
                                               data->common());
     SimplifiedOperatorReducer simple_reducer(&graph_reducer, data->jsgraph());
     RedundancyElimination redundancy_elimination(&graph_reducer, temp_zone);
     ValueNumberingReducer value_numbering(temp_zone, data->graph()->zone());
     MachineOperatorReducer machine_reducer(data->jsgraph());
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->common(), data->machine());
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &simple_reducer);
     AddReducer(data, &graph_reducer, &redundancy_elimination);
-    AddReducer(data, &graph_reducer, &value_numbering);
     AddReducer(data, &graph_reducer, &machine_reducer);
     AddReducer(data, &graph_reducer, &common_reducer);
+    AddReducer(data, &graph_reducer, &value_numbering);
     graph_reducer.ReduceGraph();
   }
 };
 
 struct ControlFlowOptimizationPhase {
   static const char* phase_name() { return "control flow optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     ControlFlowOptimizer optimizer(data->graph(), data->common(),
                                    data->machine(), temp_zone);
@@ skipping 77 matching lines @@
     RedundancyElimination redundancy_elimination(&graph_reducer, temp_zone);
     LoadElimination load_elimination(&graph_reducer, data->jsgraph(),
                                      temp_zone);
     ValueNumberingReducer value_numbering(temp_zone, data->graph()->zone());
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->common(), data->machine());
     AddReducer(data, &graph_reducer, &branch_condition_elimination);
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &redundancy_elimination);
     AddReducer(data, &graph_reducer, &load_elimination);
+    AddReducer(data, &graph_reducer, &common_reducer);
     AddReducer(data, &graph_reducer, &value_numbering);
-    AddReducer(data, &graph_reducer, &common_reducer);
     graph_reducer.ReduceGraph();
   }
 };
 
 struct MemoryOptimizationPhase {
   static const char* phase_name() { return "memory optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     // The memory optimizer requires the graphs to be trimmed, so trim now.
     GraphTrimmer trimmer(temp_zone, data->graph());
@@ skipping 18 matching lines @@
                                               data->common());
     ValueNumberingReducer value_numbering(temp_zone, data->graph()->zone());
     MachineOperatorReducer machine_reducer(data->jsgraph());
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->common(), data->machine());
     SelectLowering select_lowering(data->jsgraph()->graph(),
                                    data->jsgraph()->common());
     TailCallOptimization tco(data->common(), data->graph());
     AddReducer(data, &graph_reducer, &branch_condition_elimination);
     AddReducer(data, &graph_reducer, &dead_code_elimination);
-    AddReducer(data, &graph_reducer, &value_numbering);
     AddReducer(data, &graph_reducer, &machine_reducer);
     AddReducer(data, &graph_reducer, &common_reducer);
     AddReducer(data, &graph_reducer, &select_lowering);
     AddReducer(data, &graph_reducer, &tco);
+    AddReducer(data, &graph_reducer, &value_numbering);
     graph_reducer.ReduceGraph();
   }
 };
 
 struct EarlyGraphTrimmingPhase {
   static const char* phase_name() { return "early graph trimming"; }
   void Run(PipelineData* data, Zone* temp_zone) {
     GraphTrimmer trimmer(temp_zone, data->graph());
     NodeVector roots(temp_zone);
     data->jsgraph()->GetCachedNodes(&roots);
@@ skipping 828 matching lines @@
   data->DeleteRegisterAllocationZone();
 }
 
 CompilationInfo* PipelineImpl::info() const { return data_->info(); }
 
 Isolate* PipelineImpl::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8