Revert "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 5d33e22aac8bdeea839043241956dfc2fb504bff..ab0b54f1d689146ea7508cf6ebb1c50005375343 100644
--- a/lib/compiler/implementation/ssa/optimize.dart
+++ b/lib/compiler/implementation/ssa/optimize.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
@@ -711,11 +711,12 @@ 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.isControlFlow();
+           && instruction is !HTypeGuard;
   }
 
   void visitGraph(HGraph graph) {