Machine.Block.t live field

[Stephen Weeks]

I am trying to understand what the live field of the Machine.Block.t
type is supposed to contain.  I am confused by line 1223 of
backend.fun, which stores the liveNoFormals in this field as the lives
of a continuation label.  What I don't understand is why isn't argsl
appended to this list?  All of the operands in argsl are live, because
they are immediately used in moves to the formal parameters of the
continuation.