diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug701964.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug701964.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,36 @@
+load(libdir + 'array-compare.js');
+
+function f(v) {
+    return v.length;
+}
+
+function g(v) {
+    return v.length;
+}
+
+function h(v) {
+    return v.length;
+}
+
+function aliasCheck(v) {
+    v[0] = v.length;
+    v[1] = v.length;
+    v[2] = v.length;
+    return v;
+}
+
+for(let i = 41; i; i--) {
+    assertEq(f([]), 0);
+    assertEq(f([0]), 1);
+    assertEq(f([0, 1]), 2);
+    assertEq(f([0, 1, 2]), 3);
+    assertEq(g(""), 0);
+    assertEq(g("1"), 1);
+    assertEq(g("12"), 2);
+    assertEq(g("123"), 3);
+    assertEq(h({}), undefined);
+    assertEq(h({a: 1}), undefined);
+    assertEq(h({a: 1, b: 2}), undefined);
+    assertEq(h({a: 1, b: 2, length: 3}), 3);
+    assertEq(arraysEqual(aliasCheck([0, 1, 2]), [3, 3, 3]), true);
+}