in the old fix was missing the renaming, and there was wrong equations
order :
f () returns x
[here rename x by mem_x]
mem_x = fby ...
x = mem_x
so the simplest was :
f () returns out_x
var x;
[ nothing to do]
out_x = x
x = fby ...
pay attention to the order of equations since we are after the
scheduling..
probably it should be done before the scheduling anyway ?