Compost is used to ammend soil in your ourdoors garden. Potting soil is for...pots.
Compost will lower ph, does not drain well, and it just doesn't work as a stand-alone potting mix. Wouldn't matter how much perlite you add, it's not for cannabis. Contains stuff like weed seeds, roadkill, fungus gnat eggs, doesn't it?
As with all things in life, use the right tool for the job. It usually makes your life easier. Get some potting soil. :thumbsup: