Create While node for Cxx generation.

        It is a cxx_loop to handle else clause.

def visit_While(self, node):
        """
        Create While node for Cxx generation.

        It is a cxx_loop to handle else clause.
        """
        test = self.visit(node.test)
        body = [self.visit(n) for n in node.body]
        stmt = While(test, Block(body))
        return self.process_omp_attachements(node, stmt)