diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/parallel/bug977853-convert-doubles.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/parallel/bug977853-convert-doubles.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,63 @@
+// Bug 977853 -- Pared down version of script exhibiting negative
+// interaction with convert to doubles optimization. See bug for gory
+// details.
+
+if (!getBuildConfiguration().parallelJS)
+  quit();
+
+load(libdir + "parallelarray-helpers.js")
+
+var numIters = 5;
+var golden_output;
+
+function PJS_div4(v, s)
+{
+  return [ v[0]/s, v[1]/s, v[2]/s, v[3]/s ];
+}
+
+function PJS_normalized(v)
+{
+  var d = Math.sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
+  d = d > 0.0 ? d : 1.0;
+  var result = [ v[0]/d, v[1]/d, v[2]/d, 1.0 ];
+  return result;
+}
+
+// This is the elemental function passed to mapPar
+function PJS_displace(p)
+{
+  var position = [p[0], p[1], p[2], 1.0];
+  var normal = position;
+  var roughness = 0.025 / 0.35;
+  normal = PJS_normalized(PJS_div4(normal, roughness));
+  return null;
+}
+var NUM_VERTEX_COMPONENTS = 3;
+var initPos, nVertices;
+var userData = {
+  nVertices : 25, //2880,
+  initPos : [],
+};
+function setup() {
+  for(var k = 0; k < NUM_VERTEX_COMPONENTS*userData.nVertices; k++) {
+    userData.initPos[k] = k/1000;
+  }
+  nVertices	= userData.nVertices;
+  initPos		= new Array(nVertices);
+  for(var i=0, j=0; i<nVertices; i++, j+=NUM_VERTEX_COMPONENTS) {
+	initPos[i] = [userData.initPos[j],
+				  userData.initPos[j+1],
+				  userData.initPos[j+2]];
+  }
+}
+function SimulatePJS() {
+  var curPosAndNor;
+
+  // Measure Parallel Execution
+  assertParallelExecSucceeds(
+    function(m) { return initPos.mapPar(PJS_displace, m); },
+    function() { });
+}
+var start_time, elapsed_parallel = 0, elapsed_sequential = 0;
+setup();
+SimulatePJS();