/* move all expressions on the path to lower/upper block */
move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
/* move all expressions on the path to lower/upper block */
move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);