Implement a variation of scalar replacement for non-escaping allocations.

tests/language/allocation_sinking_vm_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// Test allocation sinking optimization.
+
+import 'package:expect/expect.dart';
+
+class Point {
+  var x, y;
+
+  Point(this.x, this.y);
+
+  operator * (other) {
+    return x * other.x + y * other.y;
+  }
+}
+
+class C {
+  var p;
+  C(this.p);
+}
+
+class D {
+  var p;
+  D(this.p);
+}
+
+// Class that is used to capture materialized Point object with * operator.
+class F {
+  var p;
+  var val;
+
+  F(this.p);
+
+  operator * (other) {
+    Expect.isTrue(other is Point);
+    Expect.equals(42.0, other.x);
+    Expect.equals(0.5, other.y);
+
+    if (val == null) {
+      val = other;
+    } else {
+      Expect.isTrue(identical(val, other));
+    }
+
+    return this.p * other;
+  }
+}
+
+test1(c, x, y) {
+  var a = new Point(x - 0.5, y + 0.5);
+  var b = new Point(x + 0.5, y + 0.8);
+  var d = new Point(c.p * a, c.p * b);
+  return d * d;
+}
+
+effects() {
+  // This function should not be inlinable.
+  try { } catch (e) { }
+}
+
+testForwardingThroughEffects(c, x, y) {
+  var a = new Point(x - 0.5, y + 0.5);
+  var b = new Point(x - 0.5, y - 0.8);
+  var d = new Point(c.p * a, c.p * b);
+  // Effects can't affect neither a, b, nor d because they do not escape.
+  effects();
+  effects();
+  return ((a == null) ? 0.0 : 0.1) + (d * d);
+}
+
+testIdentity(x) {
+  var y = new Point(42.0, 0.5);
+  var z = y;
+  return x * y + x * z;
+}
+
+class PointP<T> {
+  var x, y;
+
+  PointP(this.x, this.y);
+
+  operator * (other) {
+    return x * other.x + y * other.y;
+  }
+}
+
+foo2() => new PointP<int>(1, 3) * new PointP<num>(5, 6);
+
+main() {
+  var c = new C(new Point(0.1, 0.2));
+
+  // Compute initial values.
+  final x0 = test1(c, 11.11, 22.22);
+  final y0 = testForwardingThroughEffects(c, 11.11, 22.22);
+  final z0 = testIdentity(c.p);
+
+  // Force optimization.
+  for (var i = 0; i < 10000; i++) {
+    test1(c, i.toDouble(), i.toDouble());
+    testForwardingThroughEffects(c, i.toDouble(), i.toDouble());
+    testIdentity(c.p);
+    foo2();
+  }
+
+  // Test returned value after optimization.
+  final x1 = test1(c, 11.11, 22.22);
+  final y1 = testForwardingThroughEffects(c, 11.11, 22.22);
+
+  // Test returned value after deopt.
+  final x2 = test1(new D(c.p), 11.11, 22.22);
+  final y2 = testForwardingThroughEffects(new D(c.p), 11.11, 22.22);
+
+  Expect.equals(6465, (x0 * 100).floor());
+  Expect.equals(6465, (x1 * 100).floor());
+  Expect.equals(6465, (x2 * 100).floor());
+  Expect.equals(x0, x1);
+  Expect.equals(x0, x2);
+
+  Expect.equals(6008, (y0 * 100).floor());
+  Expect.equals(6008, (y1 * 100).floor());
+  Expect.equals(6008, (y2 * 100).floor());
+  Expect.equals(y0, y1);
+  Expect.equals(y0, y2);
+
+  // Test that identity of materialized objects is preserved correctly and
+  // no copies are materialized.
+  final z1 = testIdentity(c.p);
+  final z2 = testIdentity(new F(c.p));
+  Expect.equals(z0, z1);
+  Expect.equals(z0, z2);
+}