Cache field lowering info in mir_graph.

Change-Id: I9f9d76e3ae6c31e88bdf3f59820d31a625da020f
diff --git a/compiler/dex/bb_optimizations.h b/compiler/dex/bb_optimizations.h
index 1286a8e..bd7c40b 100644
--- a/compiler/dex/bb_optimizations.h
+++ b/compiler/dex/bb_optimizations.h
@@ -23,6 +23,20 @@
 namespace art {
 
 /**
+ * @class CacheFieldLoweringInfo
+ * @brief Cache the lowering info for fields used by IGET/IPUT/SGET/SPUT insns.
+ */
+class CacheFieldLoweringInfo : public Pass {
+ public:
+  CacheFieldLoweringInfo() : Pass("CacheFieldLoweringInfo", kNoNodes) {
+  }
+
+  void Start(CompilationUnit* cUnit) const {
+    cUnit->mir_graph->DoCacheFieldLoweringInfo();
+  }
+};
+
+/**
  * @class CodeLayout
  * @brief Perform the code layout pass.
  */