diff --git a/ChangeLog b/ChangeLog
index bdec9ca33f..6f7b9d2768 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jun 15 15:55:55 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* insns.def(setconstant, toregexp): fix to mark object correctly.
+
 Fri Jun 15 13:24:18 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* hash.c: exchange semantics of Hash#each and Hash#each_pair.
diff --git a/insns.def b/insns.def
index 02ffe11673..91607ef952 100644
--- a/insns.def
+++ b/insns.def
@@ -285,9 +285,11 @@ setconstant
     case T_CLASS:
     case T_MODULE:
 	break;
-    default:
+    default: {
+	volatile VALUE tmp = rb_obj_as_string(klass);
 	rb_raise(rb_eTypeError, "%s is not a class/module",
-		 RSTRING_PTR(rb_obj_as_string(klass)));
+		 RSTRING_PTR(tmp));
+    }
     }
 
     rb_const_set(klass, id, val);
@@ -446,6 +448,7 @@ toregexp
 (VALUE str)
 (VALUE val)
 {
+    volatile VALUE tmp = str;
     val = rb_reg_new(RSTRING_PTR(str), RSTRING_LEN(str), flag);
 }