diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/jaeger/bug719918.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/jaeger/bug719918.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+function test(m) {
+  do {
+    if (m = arr[0]) break;
+    m = 0;
+  }
+  while (0);
+  arr[1] = m;
+}
+
+arr = new Float64Array(2);
+
+// run function a lot to trigger methodjit compile
+for(var i=0; i<200; i++)
+  test(0);
+
+// should return 0, not NaN
+assertEq(arr[1], 0)