private static boolean isWideningCast(ExprNodeGenericFuncDesc engfd) {
    GenericUDF udf = engfd.getGenericUDF();
    if (!FunctionRegistry.isOpCast(udf)) {
      // It is not a cast
      return false;
    }
    return TypeInfoUtils.implicitConvertible(engfd.getChildren().get(0).getTypeInfo(),
            engfd.getTypeInfo());
  }
Get column statistics expression nodes
@param conf
         - hive conf
@param parentStats
         - parent statistics
@param end
         - expression nodes
@return column statistics
ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java