Instruction selection before removing HTypeKnown

tests/compiler/dart2js/strength_eq_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 constant folding on numbers.
+
+import "package:expect/expect.dart";
+import 'compiler_helper.dart';
+
+const String CODE = """
+class A {
+  var link;
+}
+int foo(x) {
+  if (new DateTime.now().millisecondsSinceEpoch == 42) return null;
+  var a = new A();
+  if (new DateTime.now().millisecondsSinceEpoch == 42) return a;
+  a.link = a;
+  return a;
+}
+void main() {
+  var x = foo(0);
+  return x == x.link;
+}
+""";
+
+main() {
+  // The `==` is strengthened to a HIdentity instruction.  The HIdentity follows
+  // `x.link`, so x cannot be `null`.
+  var compare = new RegExp(r'x === x\.get\$link\(\)');
+  compileAndMatch(CODE, 'main', compare);
+}