Reapply change to GVN all HFieldGet instructions.

lib/compiler/implementation/ssa/optimize.dart

Index: lib/compiler/implementation/ssa/optimize.dart
diff --git a/lib/compiler/implementation/ssa/optimize.dart b/lib/compiler/implementation/ssa/optimize.dart
index ab0b54f1d689146ea7508cf6ebb1c50005375343..5d33e22aac8bdeea839043241956dfc2fb504bff 100644
--- a/lib/compiler/implementation/ssa/optimize.dart
+++ b/lib/compiler/implementation/ssa/optimize.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, 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.
 
@@ -711,12 +711,11 @@ class SsaDeadCodeEliminator extends HGraphVisitor implements OptimizationPhase {
   final String name = "SsaDeadCodeEliminator";
 
   static bool isDeadCode(HInstruction instruction) {
-    // TODO(ngeoffray): the way we handle side effects is not right
-    // (e.g. branching instructions have side effects).
     return !instruction.hasSideEffects()
            && instruction.usedBy.isEmpty()
            && instruction is !HCheck
-           && instruction is !HTypeGuard;
+           && instruction is !HTypeGuard
+           && !instruction.isControlFlow();
   }
 
   void visitGraph(HGraph graph) {