diff --git a/collects/tests/racket/foreign-test.rktl b/collects/tests/racket/foreign-test.rktl
index f2279b02a8..ecc5589b94 100644
--- a/collects/tests/racket/foreign-test.rktl
+++ b/collects/tests/racket/foreign-test.rktl
@@ -10,6 +10,21 @@
 (test #f malloc 0 _int)
 (test #f malloc _int 0)
 
+(let ()
+  (define (try-int-boundary N _int _uint)
+    (test (- (expt 2 N)) cast (- (expt 2 N)) _int _int)
+    (test (sub1 (expt 2 N)) cast (sub1 (expt 2 N)) _int _int)
+    (test (expt 2 N) cast (expt 2 N) _uint _uint)
+    (test (sub1 (expt 2 (add1 N))) cast (sub1 (expt 2 (add1 N))) _uint _uint)
+    (err/rt-test (cast (expt 2 N) _int _int))
+    (err/rt-test (cast (sub1 (- (expt 2 N))) _int _int))
+    (err/rt-test (cast -1 _uint _uint))
+    (err/rt-test (cast (- (expt 2 N)) _uint _uint)))
+  ;(try-int-boundary 7 _int8 _uint8)
+  ;(try-int-boundary 15 _int16 _uint16)
+  (try-int-boundary 31 _int32 _uint32)
+  (try-int-boundary 63 _int64 _uint64))
+
 (let ([big/little (if (system-big-endian?) (lambda (x y) x) (lambda (x y) y))]
       [p (malloc _int32)])
   (ptr-set! p _int32 0)
diff --git a/src/racket/src/bignum.c b/src/racket/src/bignum.c
index 0ca65762dd..69727ed8ac 100644
--- a/src/racket/src/bignum.c
+++ b/src/racket/src/bignum.c
@@ -406,7 +406,7 @@ int scheme_bignum_get_long_long_val(const Scheme_Object *o, mzlonglong *v)
     *v = 0;
     return 1;
   } else if (SCHEME_BIGDIG(o)[MAX_BN_SIZE_FOR_LL - 1] == FIRST_BIT_MASK_LL 
-# ifndef USE_LONG_LONG_FOR_BIGDIG
+# if !defined(USE_LONG_LONG_FOR_BIGDIG) && !defined(SIXTY_FOUR_BIT_INTEGERS)
 	     && !SCHEME_BIGDIG(o)[0]
 # endif
 	     && !SCHEME_BIGPOS(o)) {