iTunes match - question

I recently moved to my own Apple ID, and I currently have lots of music on my iPhone tied to my Dad's Apple ID. This is fine for now, but I'd like to have everything on my own ID. The issue is that re-purchasing everything will be very, very expensive.

If I subscribe to iTunes Match, will the music on my iPhone (from the other ID) be added to my own account? Or will the service only be applicable to new music I buy on my account?