diff --git a/ChangeLog b/ChangeLog
index 6c09ae439c..db58339544 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Oct 23 10:47:16 2014  Eric Wong  <e@80x24.org>
+
+	* insns.def (getlocal,setlocal): add comment to def/opt_operand.def
+
 Thu Oct 23 10:22:41 2014  Eric Wong  <e@80x24.org>
 
 	* test/ruby/test_process.rb (test_deadlock_by_signal_at_forking):
diff --git a/insns.def b/insns.def
index bfa11a9b8d..b4f67afa9b 100644
--- a/insns.def
+++ b/insns.def
@@ -60,6 +60,7 @@ getlocal
     int i, lev = (int)level;
     VALUE *ep = GET_EP();
 
+    /* optimized insns generated for level == (0|1) in defs/opt_operand.def */
     for (i = 0; i < lev; i++) {
 	ep = GET_PREV_EP(ep);
     }
@@ -82,6 +83,7 @@ setlocal
     int i, lev = (int)level;
     VALUE *ep = GET_EP();
 
+    /* optimized insns generated for level == (0|1) in defs/opt_operand.def */
     for (i = 0; i < lev; i++) {
 	ep = GET_PREV_EP(ep);
     }