Track side-effect free paths in the graph to allow CSE and LICM for instructions that depend on som…

runtime/vm/flow_graph_optimizer.h

Index: runtime/vm/flow_graph_optimizer.h
diff --git a/runtime/vm/flow_graph_optimizer.h b/runtime/vm/flow_graph_optimizer.h
index 4bc64c3a4e06549160161d6ab12e17e6eeb8e04f..980890bf59c0741c3aac7ea13ca27105022c7f75 100644
--- a/runtime/vm/flow_graph_optimizer.h
+++ b/runtime/vm/flow_graph_optimizer.h
@@ -10,9 +10,9 @@
 
 namespace dart {
 
+class CSEInstructionMap;
 template <typename T> class GrowableArray;
-template <typename T> class DirectChainedHashMap;
-template <typename T> class PointerKeyValueTrait;
+class ParsedFunction;
 
 class FlowGraphOptimizer : public FlowGraphVisitor {
  public:
@@ -177,9 +177,6 @@ class FlowGraphOptimizer : public FlowGraphVisitor {
 };
 
 
-class ParsedFunction;
-
-
 // Loop invariant code motion.
 class LICM : public ValueObject {
  public:
@@ -215,7 +212,7 @@ class DominatorBasedCSE : public AllStatic {
   static bool OptimizeRecursive(
       FlowGraph* graph,
       BlockEntryInstr* entry,
-      DirectChainedHashMap<PointerKeyValueTrait<Instruction> >* map);
+      CSEInstructionMap* map);
 };