Ansible: compare variables

I am trying to compare some variables so here is my case:

pg_master_ip is an ip obviously.

ansible doesn't parse pg_master_ip.

bond0.stdout is a result of an earlier register task.

If I could use {{ hostvars[inventory_hostname]['ansible_bond0'].ipv4.address }} I'd be happier but I don't know how.

- name: pgsql and pgpool initiate master
  include: master.yml
  when: bond0.stdout == '{{pg_master_ip}}'

Thank you for the advice in advance.