dart2js cps: Clean up and avoid processing unreachable code.

pkg/compiler/lib/src/tree_ir/optimization/logical_rewriter.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.
 
 library tree_ir.optimization.logical_rewriter;
 
 import '../tree_ir_nodes.dart';
 import 'optimization.dart' show Pass;
 import '../../constants/values.dart' as values;
 
@@ skipping 45 matching lines @@
                       implements Pass {
   String get passName => 'Logical rewriter';
 
   @override
   void rewrite(FunctionDefinition node) {
     node.body = visitStatement(node.body);
   }
 
   final FallthroughStack fallthrough = new FallthroughStack();
 
-  @override
-  void visitInnerFunction(FunctionDefinition node) {
-    new LogicalRewriter().rewrite(node);
-  }
-
   /// True if the given statement is equivalent to its fallthrough semantics.
   ///
   /// This means it will ultimately translate to an empty statement.
   bool isFallthrough(Statement node) {
     return node is Break && isFallthroughBreak(node) ||
            node is Continue && isFallthroughContinue(node) ||
            node is Return && isFallthroughReturn(node);
   }
 
   bool isFallthroughBreak(Break node) {
@@ skipping 455 matching lines @@
   }
 
   Expression makeOr(Expression e1, Expression e2, {bool liftNots: true}) {
     if (e1 is Not && e2 is Not && liftNots) {
       return new Not(new LogicalOperator.and(e1.operand, e2.operand));
     } else {
       return new LogicalOperator.or(e1, e2);
     }
   }
 
-  /// True if [e2] is known to return the same value as [e1] 
+  /// True if [e2] is known to return the same value as [e1]
   /// (with no additional side effects) if evaluated immediately after [e1].
-  /// 
+  ///
   /// Concretely, this is true if [e1] and [e2] are uses of the same variable,
   /// or if [e2] is a use of a variable assigned by [e1].
   bool isSameVariable(Expression e1, Expression e2) {
     if (e1 is VariableUse) {
       return e2 is VariableUse && e1.variable == e2.variable;
     } else if (e1 is Assign) {
       return e2 is VariableUse && e1.variable == e2.variable;
     }
     return false;
   }
 
   void destroyVariableUse(VariableUse node) {
     --node.variable.readCount;
   }
 }