Merge chains of straight-line blocks.

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 9097 matching lines @@
 
         // Replace the false target entry with the new join entry. We will
         // recompute the dominators after this pass.
         join->LinkTo(next);
         branch->UnuseAllInputs();
       }
     }
   }
 
   graph_->DiscoverBlocks();
+  graph_->MergeBlocks();
   GrowableArray<BitVector*> dominance_frontier;
   graph_->ComputeDominators(&dominance_frontier);
 
   if (FLAG_trace_constant_propagation) {
     OS::Print("\n==== After constant propagation ====\n");
     FlowGraphPrinter printer(*graph_);
     printer.PrintBlocks();
   }
 }
 
@@ skipping 947 matching lines @@
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits_collector_.exits().length(); i++) {
     CreateMaterializationAt(
         exits_collector_.exits()[i], alloc, alloc->cls(), *slots);
   }
 }
 
 
 }  // namespace dart