Deoptimization tests for instance field increment optimization.

language/src/InstanceIncrDeoptTest.dart

+// Copyright (c) 2011, 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.
+
+// Check correct deoptimization of instance field increment.
+
+
+main() {
+  var a = new A();
+  var aa = new A();
+  for (int i = 0; i < 2000; i++) {
+    a.Incr();
+    myIncr(aa);
+  }
+  Expect.equals(2000, a.f);
+  Expect.equals(2000, aa.f);
+  a.f = 1.0;
+  // Deoptimize ++ part of instance increment.
+  a.Incr();
+  Expect.equals(2.0, a.f);
+  var b = new B();
+  // Deoptimize getfield part of instance increment.
+  myIncr(b);
+  Expect.equals(1.0, b.f);

[regis, 2011/11/02 02:06:37]

Do you use a double for a particular reason? b.f holds an int.

[srdjan, 2011/11/02 15:10:55]

Good catch, this would fail in type checked mode. Changed field f to var. I am
setting f to double so that the type assumption at ++(expecting Smi) is
invalidated and deoptimization occurs.

+}
+
+myIncr(var a) {
+  a.f++;
+}
+
+class A {
+  A() : f = 0;
+  Incr() {
+    f++;
+  }
+  int f;
+}
+
+class B {
+  B() : f = 0;
+  int f;
+}
+