diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testHoleInDenseArray.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testHoleInDenseArray.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,16 @@
+var s;
+
+function f(i) {
+    if (i > 4) /* side exit when arr[i] changes from bool to undefined (via a hole) */
+        assertEq(s, undefined);
+    else
+        assertEq(s, false);
+    return 1;
+}
+
+/* trailing 'true' ensures array has capacity >= 10 */
+var arr = [ false, false, false, false, false, , , , , , true ];
+
+for (var i = 0; i < 10; ++i) {
+    (s = arr[i]) + f(i);
+}