Input validation for login page

We have a password input for both our login and signup pages. As the user types their password on the signup page, they will see something resembling the following:

Password popup showing validation

Note: Our password input doesn't have the strength text.

My question is, would having the same password input on both the login and signup pages have a negative impact on the user experience? I assume there is a good reason other websites don't do this but I'll list the pros and cons as I see it.

Pros

  1. Immediate pre-request validation
  2. Knowing the requirements may help the user remember their password

Cons

  1. Additional clutter on the login screen
  2. Password requirements may change after signup