diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 9b7ff88..e9b6b41 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -2123,7 +2123,7 @@
 #undef DECLARE_VISIT_INSTRUCTION
 
  private:
-  HGraph* graph_;
+  HGraph* const graph_;
 
   DISALLOW_COPY_AND_ASSIGN(HGraphVisitor);
 };