diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug847412.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug847412.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,19 @@
+
+var gTestcases = new Array();
+var gTc = gTestcases.length;
+function TestCase( a) {
+  this.actual = a;
+  gTestcases[gTc++] = this;
+}
+function test() {
+  for ( gTc=0; gTc < gTestcases.length; gTc++ ) {
+	gTestcases[gTc].actual.toString()
+  }
+}
+function testOverwritingSparseHole() {
+  for (var i = 0; i < 50; i++)
+    new TestCase(eval("VAR1 = 0; VAR2 = -1; VAR1 %= VAR2; VAR1"));
+}
+testOverwritingSparseHole();
+test();
+this.toSource();