diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/parallel/bug970427.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/parallel/bug970427.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+// XXXshu: I tried wrapping the entire test in an |if (pjs)|, but the timing
+// is fragile and it no longer reproduced the bug, thus getting this value at
+// the beginning.
+var pjs = getBuildConfiguration().parallelJS;
+function f(a, b) {
+  var o = a;
+  gczeal(2);
+}
+f(3, 4);
+var len = 5000;
+var iters = 100;
+for (var i = 0; i < iters; i++) {
+  var par = pjs ? Array.buildPar(len, fill) : true;
+}
+function fill(i) { return 10/i; }