Ignore value and add value

Hello im in a situation where im [Philippa] vs [Eredin] and i attack with [[Regicide]] and my opponent defends with [[Icy Guile]] what happens?? according to the core rules defenders effects go first and then attackers and if something says ignore its value treat it as 0 but in this case would it be 3 to 0 and then 6 or just 0