diff --git a/ChangeLog b/ChangeLog
index 0ee7f87ed0..1893a81906 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Mar 27 01:19:50 2009  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (rb_cmpint): FIX2INT may fail on LP64 platforms.
+
 Fri Mar 13 21:11:51 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* ext/sdbm/_sdbm.c: should include "ruby/defines.h" as well for
diff --git a/bignum.c b/bignum.c
index 35db091454..5a608774e7 100644
--- a/bignum.c
+++ b/bignum.c
@@ -56,7 +56,12 @@ rb_cmpint(VALUE val, VALUE a, VALUE b)
     if (NIL_P(val)) {
 	rb_cmperr(a, b);
     }
-    if (FIXNUM_P(val)) return FIX2INT(val);
+    if (FIXNUM_P(val)) {
+        long l = FIX2LONG(val);
+        if (l > 0) return 1;
+        if (l < 0) return -1;
+        return 0;
+    }
     if (TYPE(val) == T_BIGNUM) {
 	if (BIGZEROP(val)) return 0;
 	if (RBIGNUM_SIGN(val)) return 1;