diff --git a/ChangeLog b/ChangeLog
index 8c1f1b4ee1..a512e4022a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Tue Dec 04 13:55:07 2012  Koichi Sasada  <ko1@atdot.net>
+
+	* vm_opts.h: enable optimization - operand unifications.
+	  Operand unification technique enable to combine
+	  an instruction and specific operands and make new
+	  instruction.
+
+	* defs/opt_operand.def: add several configuration
+	  of operand unifications.
+
+	* insns.def: use `int' instead to suppress warning.
+
 Mon Dec  3 17:58:53 2012  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* parse.y: replase parser->enc with current_enc.
diff --git a/defs/opt_operand.def b/defs/opt_operand.def
index 5ca1d74028..ab7103a421 100644
--- a/defs/opt_operand.def
+++ b/defs/opt_operand.def
@@ -7,53 +7,16 @@
 #  wildcard: *
 #
 
-__END__
-
-getlocal 2
-getlocal 3
-getlocal 4
-
-setlocal 2
-setlocal 3
-setlocal 4
-
-getdynamic *, 0
-getdynamic 1, 0
-getdynamic 2, 0
-getdynamic 3, 0
-getdynamic 4, 0
-
-setdynamic *, 0
-setdynamic 1, 0
-setdynamic 2, 0
-setdynamic 3, 0
-setdynamic 4, 0
+getlocal *, 0
+getlocal *, 1
+setlocal *, 0
+setlocal *, 1
 
 putobject INT2FIX(0)
 putobject INT2FIX(1)
-putobject Qtrue
-putobject Qfalse
-
-# CALL
-send *, *, Qfalse, 0, *
-send *, 0, Qfalse, 0, *
-send *, 1, Qfalse, 0, *
-send *, 2, Qfalse, 0, *
-send *, 3, Qfalse, 0, *
-
-# FCALL
-send *, *, Qfalse, 0x04, *
-send *, 0, Qfalse, 0x04, *
-send *, 1, Qfalse, 0x04, *
-send *, 2, Qfalse, 0x04, *
-send *, 3, Qfalse, 0x04, *
-
-# VCALL
-send *, 0, Qfalse, 0x0c, *
-
 
 __END__
 
-
-
+putobject Qtrue
+putobject Qfalse
 
diff --git a/insns.def b/insns.def
index dc7a0137d4..ea099060c7 100644
--- a/insns.def
+++ b/insns.def
@@ -57,10 +57,11 @@ getlocal
 ()
 (VALUE val)
 {
-    rb_num_t i;
+    int i, lev = (int)level;
     VALUE *ep = GET_EP();
-    for (i = 0; i < level; i++) {
-	ep = GET_PREV_EP(ep);
+
+    for (i = 0; i < lev; i++) {
+	    ep = GET_PREV_EP(ep);
     }
     val = *(ep - idx);
 }
@@ -78,9 +79,10 @@ setlocal
 (VALUE val)
 ()
 {
-    rb_num_t i;
+    int i, lev = (int)level;
     VALUE *ep = GET_EP();
-    for (i = 0; i < level; i++) {
+
+    for (i = 0; i < lev; i++) {
 	ep = GET_PREV_EP(ep);
     }
     *(ep - idx) = val;
diff --git a/vm_opts.h b/vm_opts.h
index f77b01886e..b5c91ea809 100644
--- a/vm_opts.h
+++ b/vm_opts.h
@@ -41,7 +41,7 @@
 #define OPT_BLOCKINLINING            0
 
 /* architecture independent, affects generated code */
-#define OPT_OPERANDS_UNIFICATION     0
+#define OPT_OPERANDS_UNIFICATION     1
 #define OPT_INSTRUCTIONS_UNIFICATION 0
 #define OPT_UNIFY_ALL_COMBINATION    0
 #define OPT_STACK_CACHING            0
@@ -50,7 +50,7 @@
 #define SUPPORT_JOKE                 0
 
 #ifndef VM_COLLECT_USAGE_DETAILS
-#define VM_COLLECT_USAGE_DETAILS 0
+#define VM_COLLECT_USAGE_DETAILS     0
 #endif
 
 #endif /* RUBY_VM_OPTS_H */