1 files changed, 58 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/arrays/apply-optimization.js b/js/src/jit-test/tests/arrays/apply-optimization.js
new file mode 100644
index 0000000000..fc62da910f
--- /dev/null
+++ b/js/src/jit-test/tests/arrays/apply-optimization.js
@@ -0,0 +1,58 @@
+function make(k) {
+    var a = new Array(k);
+    for ( let i=0 ; i < k ; i++ )
+	a[i] = {}
+    return a;
+}
+
+function g() {
+    return arguments.length;
+}
+
+function f(a) {
+    var sum = 0;
+    for ( let i=0 ; i < 1000 ; i++ )
+	sum += g.apply(null, a);
+    return sum;
+}
+
+function F2() {
+    var sum = 0;
+    for ( let i=0 ; i < 1000 ; i++ )
+	sum += g.apply(null, arguments);
+    return sum;
+}
+
+function F(a) {
+    return F2.apply(null, a);
+}
+
+function time(k, t) {
+    var then = Date.now();
+    assertEq(t(), 1000*k);
+    var now = Date.now();
+    return now - then;
+}
+
+function p(v) {
+    // Uncomment to see timings
+    // print(v);
+}
+
+f(make(200));
+
+// There is currently a cutoff after 375 where we bailout in order to avoid
+// handling very large stack frames.  This slows the operation down by a factor
+// of 100 or so.
+
+p(time(374, () => f(make(374))));
+p(time(375, () => f(make(375))));
+p(time(376, () => f(make(376))));
+p(time(377, () => f(make(377))));
+
+F(make(200));
+
+p(time(374, () => F(make(374))));
+p(time(375, () => F(make(375))));
+p(time(376, () => F(make(376))));
+p(time(377, () => F(make(377))));