diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/mathRound.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/mathRound.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,48 @@
+// Test Math.round() for IonMonkey.
+// Requires --ion-eager to enter at the top of each loop.
+
+var roundDTests = [
+	[-0, -0],
+	[0.49999999999999997, 1],
+	[0.5, 1],
+	[1.0, 1],
+	[1.5, 2],
+	[792.8, 793],
+	[-0.1, -0],
+	[-1.0001, -1],
+	[-3.14, -3],
+	[2137483649.5, 2137483650],
+	[2137483648.5, 2137483649],
+	[2137483647.1, 2137483647],
+	[900000000000, 900000000000],
+	[-0, -0],
+	[-Infinity, -Infinity],
+	[Infinity, Infinity],
+	[NaN, NaN],
+	[-2147483648.8, -2147483649],
+	[-2147483649.8, -2147483650]
+];
+
+var roundITests = [
+	[0, 0],
+	[4, 4],
+	[2147483648, 2147483648],
+	[-2147483649, -2147483649]
+];
+
+// Typed functions to be compiled by Ion.
+function roundD(x) { return Math.round(x); }
+function roundI(x) { return Math.round(x); }
+
+function test() {
+	// Always run this function in the interpreter.
+	try {} catch (e) {}
+
+	for (var i = 0; i < roundDTests.length; i++)
+		assertEq(roundD(roundDTests[i][0]), roundDTests[i][1]);
+	for (var i = 0; i < roundITests.length; i++)
+		assertEq(roundI(roundITests[i][0]), roundITests[i][1]);
+}
+
+for (var i = 0; i < 40; i++)
+	test();