diff --git a/ChangeLog b/ChangeLog
index e04a51193e..8f14ec6da2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,8 @@ Fri Jul 13 17:32:37 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
 	* vm.c (vm_free): clear free'ed living_threads field.
 	  [ruby-dev:31163]
 
+	* insns.def (opt_succ): use cast to shut a warning up.
+
 Fri Jul 13 16:10:00 2007  Tanaka Akira  <akr@fsij.org>
 
 	* lib/open-uri.rb (URI::Generic#find_proxy): use ENV.to_hash to access
diff --git a/insns.def b/insns.def
index b22b76323a..066b0a4723 100644
--- a/insns.def
+++ b/insns.def
@@ -2304,7 +2304,7 @@ opt_succ
 	    const VALUE obj = INT2FIX(1);
 	    /* fixnum + INT2FIX(1) */
 	    val = (recv + (obj & (~1)));
-	    if ((~(recv ^ obj) & (recv ^ val)) & (LONG_MAX + 1)) {
+	    if ((~(recv ^ obj) & (recv ^ val)) & ((unsigned long)LONG_MAX + 1)) {
 		val = rb_big_plus(rb_int2big(FIX2LONG(recv)),
 				  rb_int2big(FIX2LONG(obj)));
 	    }