diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/parallel/int32-overflow.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/parallel/int32-overflow.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,10 @@
+function testMap() {
+  // Test overflow
+  var p = [1 << 30];
+  var m = p.mapPar(function(x) { return x * 4; });
+  assertEq(m[0], (1 << 30) * 4);
+}
+
+if (getBuildConfiguration().parallelJS)
+  testMap();
+