[13] RFR(XS):8226287: Make process_users_of_allocation handle gc barriers

[Roland Westrelin]

> The loadbarrier is left hanging. Later in expand_loadbarrier_node we 
> crash when trying to remove a dead node  in 
> PhaseIterGVN::remove_globally_dead_node(Node*).
>
> Sometimes "assert(init->in(TypeFunc::Control) == _fallthroughcatchproj)" 
> in macro.cpp line~1006 catches the problem.

Wouldn't there be a way to remove the init barrier anyway? Doesn't:

_igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));

always work?

Roland.