PHP does not query the database with rowCount()

Question

Good people I am making a Login system, but I believe, I have a problem with the connection with the database, because only returns the value false, and true involves a query with the BD... below follows the Cód.:

This is the connection to the database:

<?php
function __autoload($class){require_once"{$class}.class.php";}

abstract class ConDB{
    private $cnx;
    private function setConn(){
        return
        is_null($this->cnx)?
                $this->cnx=new PDO('mysql:host=localhost;dbname=silkgra','admin','admin'):
                $this->cnx;
    }

    public function getConn(){
        return $this->setConn();
    }
}

    $lgn=new Login;
    var_dump($lgn->setLogin('[email protected]','12345678'));

?>

This is the Cód. of Login:

<?php
class Login{
    private $vem,$vsh,$cpt,$crud,$email,$senha,$log,$dds;
    public function setLogin($email,$senha){
        $this->vem=new ValidaEmail;
        $this->vsh=new ValidaSenha;
        $this->cpt=new Cripto;
        $this->crud=new CRUD;

        $this->email=$this->vem->setValidaEmail($email);
        $this->senha=$this->vsh->setValidaSenha($senha);

        $this->log=$this->senha==$senha?
                    $this->crud->select('idUsuario','usuario','WHERE email=? && senha=?',
                    array($this->email,$this->cpt->setCripto($this->senha))):
                    FALSE;

        return $this->log->rowCount();

        if($this->log && $this->log->rowCount()>0){
            foreach($this->log as $this->dds){
                $_SESSION['logado']=$this->dds;
                return true;
                //header('location:../../admin/');
            }
        } else {
            return 'Acesso Negado...';
        }
    }
}

?>

THIS IS THE PRINT OF THE DATABASE:

happens q when use data q are already in the database does not return anything, but I have these data stored

when I go to do the test appears the following error:

Fatal error: Call to a Member Function rowCount() on Boolean in C: xampp htdocs silkgra require class Login.class.php on line 18

Ae rray take a look, this is the CRUD file I made to make the connection:

<?php
class CRUD extends ConDB{
    private $query;
    private function prepExec($prep,$exec){
        $this->query=$this->getConn()->prepare($prep);
        $this->query->execute($exec);
        if(!$pdo->execute()){ print_r($pdo->errorInfo()); die('deu ruim');}
    }

    public function insert($table,$cond,$exec){ // o $cond aqui remete a condição
        $this->prepExec('INSERT INTO '.$table.' SET '.$cond.'',$exec);
        return $this->getConn()->lastInsertId();
    }

    public function select($fields,$table,$cond,$exec){
        $this->prepExec('SELECT '.$fields.' FROM '.$table.' '.$cond.'',$exec);
        return $this->query;
    }

    public function update($table,$cond,$exec){
        $this->prepExec('UPDATE '.$table.' SET '.$cond.'',$exec);
    }

    public function delete($table,$cond,$exec){
        $this->prepExec('DELETE FROM '.$table.' '.$cond.'',$exec);
    }

}

?>

Ai rray, returned this brother