live.fun question

[Stephen Weeks]

I am confused by the existence of line 249 of backend/live.fun, which
contains the following

 	val _ = List.push (link_defuse, Use b)

I don't understand why we need to force a use of the link here.  I
understand that we need to force a use of the code because a pointer
to it is stored in the globalExnStack and may be used by the callee.
But the link is solely for use by the caller.  If indeed the link is
live, won't that be captured by a SetExnStackSlot somewhere down the
control-flow path of the continuation?