First optimization in new compiler: simple GVN.

Change-Id: Ibe0efa4e84fd020a53ded310a92e0b4363f91b12
diff --git a/compiler/optimizing/graph_visualizer.h b/compiler/optimizing/graph_visualizer.h
index 7cd74e9..6e2c6fd 100644
--- a/compiler/optimizing/graph_visualizer.h
+++ b/compiler/optimizing/graph_visualizer.h
@@ -25,8 +25,10 @@
 class DexCompilationUnit;
 class HGraph;
 
+// TODO: Create an analysis/optimization abstraction.
 static const char* kLivenessPassName = "liveness";
 static const char* kRegisterAllocatorPassName = "register";
+static const char* kGVNPassName = "gvn";
 
 /**
  * If enabled, emits compilation information suitable for the c1visualizer tool