Implement graph trimming in ControlReducer.

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 <sstream>
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/compiler/ast-graph-builder.h"
 #include "src/compiler/basic-block-instrumentor.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/code-generator.h"
+#include "src/compiler/control-reducer.h"
 #include "src/compiler/graph-replay.h"
 #include "src/compiler/graph-visualizer.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/instruction-selector.h"
 #include "src/compiler/js-context-specialization.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-inlining.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/machine-operator-reducer.h"
 #include "src/compiler/phi-reducer.h"
@@ skipping 320 matching lines @@
       // TODO(titzer): Figure out if we should run all reducers at once here.
       graph_reducer.AddReducer(&vn_reducer);
       graph_reducer.AddReducer(&simple_reducer);
       graph_reducer.AddReducer(&lowering);
       graph_reducer.AddReducer(&mach_reducer);
       graph_reducer.ReduceGraph();
 
       // TODO(jarin, rossberg): Remove UNTYPED once machine typing works.
       VerifyAndPrintGraph(&graph, "Lowered changes", true);
     }
+
+    {
+      SourcePositionTable::Scope pos(&source_positions,
+                                     SourcePosition::Unknown());
+      PhaseStats control_reducer_stats(info(), PhaseStats::CREATE_GRAPH,
+                                       "control reduction");
+      ControlReducer::ReduceGraph(&jsgraph, &common);
+
+      VerifyAndPrintGraph(&graph, "Control reduced");
+    }
   }
 
   {
     // Lower any remaining generic JSOperators.
     PhaseStats lowering_stats(info(), PhaseStats::CREATE_GRAPH,
                               "generic lowering");
     SourcePositionTable::Scope pos(&source_positions,
                                    SourcePosition::Unknown());
     JSGenericLowering lowering(info(), &jsgraph);
     GraphReducer graph_reducer(&graph);
@@ skipping 136 matching lines @@
 }
 
 
 void Pipeline::TearDown() {
   InstructionOperand::TearDownCaches();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8