At the gate I briefed... any problems after V1 I will take the aircraft into the air and we will climb to a safe altitude, troubleshoot and run any appropriate checklists, declare an emergency if necessary, and return to XYZ airport.

That would be my answer. V1 and Vr are usually so close together that if you come across V1 you usually are already at or within a few knots of Vr so do as you briefed and as you are trained. If your airspeed hits V1 and then degrades below V1 then you are below V1 and again do as you briefed and are trained.

We are talking about a split second decision here, so make your call and then stick to it....the only right answer is the one that leads to everyone getting off the airplane alive.