Change comparison-to-branch fusion to actually remove comparison from the graph.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
diff --git a/runtime/vm/intermediate_language.h b/runtime/vm/intermediate_language.h
index 407e181af3fcb7cd029e8dec6953a0327ad5fd95..af8384180c2006f54d7c6e608106114823407b9c 100644
--- a/runtime/vm/intermediate_language.h
+++ b/runtime/vm/intermediate_language.h
@@ -2279,7 +2279,7 @@ class BranchInstr : public InstructionWithInputs {
         value_(value),
         true_successor_(NULL),
         false_successor_(NULL),
-        is_fused_with_comparison_(false),
+        fused_with_comparison_(NULL),
         is_negated_(false) { }
 
   DECLARE_INSTRUCTION(Branch)
@@ -2309,11 +2309,13 @@ class BranchInstr : public InstructionWithInputs {
   void EmitBranchOnCondition(FlowGraphCompiler* compiler,
                              Condition true_condition);
 
-  void MarkFusedWithComparison() {
-    is_fused_with_comparison_ = true;
+  void MarkFusedWithComparison(ComparisonComp* comp) {
+    fused_with_comparison_ = comp;
   }
 
-  bool is_fused_with_comparison() const { return is_fused_with_comparison_; }
+  bool is_fused_with_comparison() const {
+    return fused_with_comparison_ != NULL;
+  }
   bool is_negated() const { return is_negated_; }
   void set_is_negated(bool value) { is_negated_ = value; }
 
@@ -2321,7 +2323,7 @@ class BranchInstr : public InstructionWithInputs {
   Value* value_;
   TargetEntryInstr* true_successor_;
   TargetEntryInstr* false_successor_;
-  bool is_fused_with_comparison_;
+  ComparisonComp* fused_with_comparison_;
   bool is_negated_;
 
   DISALLOW_COPY_AND_ASSIGN(BranchInstr);