[turbofan] Eliminate a few redundant bounds checks.

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 901 matching lines @@
     AddReducer(data, &graph_reducer, &intrinsic_lowering);
     AddReducer(data, &graph_reducer, &value_numbering);
     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) {
-    JSGraphReducer graph_reducer(data->jsgraph(), temp_zone);
-    BranchElimination branch_condition_elimination(&graph_reducer,
-                                                   data->jsgraph(), temp_zone);
-    DeadCodeElimination dead_code_elimination(&graph_reducer, data->graph(),
-                                              data->common());
-    AddReducer(data, &graph_reducer, &branch_condition_elimination);
-    AddReducer(data, &graph_reducer, &dead_code_elimination);
-    graph_reducer.ReduceGraph();
-  }
-};
-
-
 struct EscapeAnalysisPhase {
   static const char* phase_name() { return "escape analysis"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     EscapeAnalysis escape_analysis(data->graph(), data->jsgraph()->common(),
                                    temp_zone);
     escape_analysis.Run();
     JSGraphReducer graph_reducer(data->jsgraph(), temp_zone);
     EscapeAnalysisReducer escape_reducer(&graph_reducer, data->jsgraph(),
                                          &escape_analysis, temp_zone);
@@ skipping 122 matching lines @@
     MemoryOptimizer optimizer(data->jsgraph(), temp_zone);
     optimizer.Optimize();
   }
 };
 
 struct LateOptimizationPhase {
   static const char* phase_name() { return "late optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     JSGraphReducer graph_reducer(data->jsgraph(), temp_zone);
+    BranchElimination branch_condition_elimination(&graph_reducer,
+                                                   data->jsgraph(), temp_zone);
     DeadCodeElimination dead_code_elimination(&graph_reducer, data->graph(),
                                               data->common());
     ValueNumberingReducer value_numbering(temp_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);
     graph_reducer.ReduceGraph();
   }
 };
 
@@ skipping 405 matching lines @@
   data->BeginPhaseKind("block building");
 
   Run<EffectControlLinearizationPhase>();
   RunPrintAndVerify("Effect and control linearized", true);
 
   if (FLAG_turbo_store_elimination) {
     Run<StoreStoreEliminationPhase>();
     RunPrintAndVerify("Store-store elimination", true);
   }
 
-  Run<BranchEliminationPhase>();
-  RunPrintAndVerify("Branch conditions eliminated", true);
-
   // Optimize control flow.
   if (FLAG_turbo_cf_optimization) {
     Run<ControlFlowOptimizationPhase>();
     RunPrintAndVerify("Control flow optimized", true);
   }
 
   // Optimize memory access and allocation operations.
   Run<MemoryOptimizationPhase>();
   // TODO(jarin, rossberg): Remove UNTYPED once machine typing works.
   RunPrintAndVerify("Memory optimized", true);
@@ skipping 324 matching lines @@
   data->DeleteRegisterAllocationZone();
 }
 
 CompilationInfo* PipelineImpl::info() const { return data_->info(); }
 
 Isolate* PipelineImpl::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8