First implementation of store elimination.

src/hydrogen-store-elimination.h

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-#ifndef V8_HYDROGEN_INFER_REPRESENTATION_H_
-#define V8_HYDROGEN_INFER_REPRESENTATION_H_
+#ifndef V8_HYDROGEN_STORE_ELIMINATION_H_
+#define V8_HYDROGEN_STORE_ELIMINATION_H_
 
 #include "hydrogen.h"
+#include "hydrogen-alias-analysis.h"
 
 namespace v8 {
 namespace internal {
 
-
-class HInferRepresentationPhase : public HPhase {
+class HStoreEliminationPhase : public HPhase {
  public:
-  explicit HInferRepresentationPhase(HGraph* graph)
-      : HPhase("H_Infer representations", graph),
-        worklist_(8, zone()),
-        in_worklist_(graph->GetMaximumValueID(), zone()) { }
+  explicit HStoreEliminationPhase(HGraph* graph)
+    : HPhase("H_Store elimination", graph),
+      unobserved_(10, graph->zone()),  // TODO(titzer): can be phase local.

[Hannes Payer (out of office), 2014/01/16 15:25:21]

why not phase local?

+      aliasing_() { }
 
   void Run();
-  void AddToWorklist(HValue* current);
+ private:
+  ZoneList<HStoreNamedField*> unobserved_;
+  HAliasAnalyzer* aliasing_;
 
- private:
-  ZoneList<HValue*> worklist_;
-  BitVector in_worklist_;
-
-  DISALLOW_COPY_AND_ASSIGN(HInferRepresentationPhase);
+  void ProcessStore(HStoreNamedField* store);
+  void ProcessLoad(HLoadNamedField* load);
+  void ProcessInstr(HInstruction* instr, GVNFlagSet flags);
 };
 
 
 } }  // namespace v8::internal
 
-#endif  // V8_HYDROGEN_INFER_REPRESENTATION_H_
+#endif