Allocation sinking for contexts.

tests/language/vm/load_elimination_any_use_creates_alias_test.dart

+// Copyright (c) 2014, 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 correctness of side effects tracking used by load to load forwarding.
+
+// VMOptions=--no-use-osr --optimization-counter-threshold=10 --enable-inlining-annotations
+
+import "package:expect/expect.dart";
+
+const alwaysInline = "AlwaysInline";
+const noInline = "NeverInline";
+
+B G;
+
+@noInline
+modify() {
+  G.bval = 123;
+}
+
+class B {
+
+ @alwaysInline
+ poly() {
+   G = this;
+   modify();
+   return bval;
+ }
+ var bval = -1;
+}
+
+class C {
+  poly() => null;
+}
+
+
+@alwaysInline
+foo(obj) => obj.poly();
+
+@noInline
+test() {
+  var b = new B();
+
+  foo(b);
+  return b.bval;
+}
+
+main() {
+  foo(new C());
+  foo(new B());
+  for (var i = 0; i < 100; i++) test();
+  Expect.equals(123, test());
+}