Have reason to believe that my management is placing me under PIP, and even if I did survive the program, it would automatically result in a soured relationship between myself and my manager.

Assuming I get placed on a PIP and said PIP has a 1-month review with a clause stating "Failure to meet the management's outlined expectations of the role will result in a termination or performance review," and I tender my resignation which has a 3-month notice halfway through the PIP, do I follow the time outlined in PIP or my resignation?

Asked several HR practitioner friends, but want to be sure. I understand that in theory, a PIP is not a termination, so a resignation letter and its notice period take priority. Does anyone else think differently?

Update to the above. Finally found the courage to put in my notice. Have 14 ALs to clear off, any HR folks can share if it's possible to encash these? Year end no plans to go anywhere, might as well just enter work as usual and get the gold.