diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug747271.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug747271.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,18 @@
+// vim: set ts=8 sts=4 et sw=4 tw=99:
+function randomFloat () {
+    // note that in fuzz-testing, this can used as the size of a buffer to allocate.
+    // so it shouldn't return astronomic values. The maximum value 10000000 is already quite big.
+    var fac = 1.0;
+    var r = Math.random();
+    if (r < 0.25)
+        fac = 10;
+    else if (r < 0.7)
+        fac = 10000000;
+    else if (r < 0.8)
+        fac = NaN;
+    return -0.5*fac + Math.random() * fac;
+}
+
+for (var i = 0; i < 100000; i++)
+    randomFloat();
+