AOT: Enable branch merging for checked smi comparisons

runtime/vm/constant_propagator.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/constant_propagator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_range_analysis.h"
@@ skipping 923 matching lines @@
 
   SetValue(binary_op, non_constant_);
 }
 
 
 void ConstantPropagator::VisitCheckedSmiOp(CheckedSmiOpInstr* instr) {
   SetValue(instr, non_constant_);
 }
 
 
+void ConstantPropagator::VisitCheckedSmiComparison(
+    CheckedSmiComparisonInstr* instr) {
+  SetValue(instr, non_constant_);
+}
+
+
 void ConstantPropagator::VisitBinarySmiOp(BinarySmiOpInstr* instr) {
   VisitBinaryIntegerOp(instr);
 }
 
 
 void ConstantPropagator::VisitBinaryInt32Op(BinaryInt32OpInstr* instr) {
   VisitBinaryIntegerOp(instr);
 }
 
 
@@ skipping 761 matching lines @@
   GrowableArray<BitVector*> dominance_frontier;
   graph_->ComputeDominators(&dominance_frontier);
 
   if (FLAG_trace_constant_propagation &&
       FlowGraphPrinter::ShouldPrint(graph_->function())) {
     FlowGraphPrinter::PrintGraph("After CP", graph_);
   }
 }
 
 }  // namespace dart