diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/value-done-access.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/value-done-access.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+// Test that each yield* loop just checks "done", and "value" is only
+// fetched once at the end.
+
+load(libdir + 'iteration.js');
+
+var log = "";
+
+function Iter(val, count) {
+    function next() {
+        return {
+            get done() { log += "d"; return count-- == 0; },
+            get value() { log += "v"; return val; }
+        }
+    }
+
+    this[std_iterator] = function() { return this; };
+    this.next = next;
+}
+
+for (var x of new Iter(42, 5))
+    assertEq(x, 42);
+
+assertEq(log, "dvdvdvdvdvd");