Review

class OptimizeReturns {
  /**
   * For the supplied function node, rewrite all the return expressions so that:
   *    return foo();
   * becomes:
   *    foo(); return;
   * Useless return will be removed later by the peephole optimization passes.
   */
  private void rewriteReturns(
      final SimpleDefinitionFinder defFinder, Node fnNode) {
    Preconditions.checkState(NodeUtil.isFunction(fnNode));
    NodeUtil.visitPostOrder(
      fnNode.getLastChild(),
      new NodeUtil.Visitor() {
        @Override
        public void visit(Node node) {
          if (node.getType() == Token.RETURN && node.hasOneChild()) {
            boolean keepValue = NodeUtil.mayHaveSideEffects(
                node.getFirstChild(), compiler);
            if (!keepValue) {
              defFinder.removeReferences(node.getFirstChild());
            }
            Node result = node.removeFirstChild();
            if (keepValue) {
              node.getParent().addChildBefore(
                new Node(
                  Token.EXPR_RESULT, result).copyInformationFrom(result), node);
            }
            compiler.reportCodeChange();
          }
        }
      },
      new NodeUtil.MatchShallowStatement());
  }

}