let computeFirstPredecessor (s: stmt) data =
match s.skind with
| Switch (exp,_,_,_)
| If (exp,_,_,_)
| Return (Some exp, _) ->
let inputs = !From.find_deps_no_transitivity s exp in
{data with
over_inputs =
Zone.join data.over_inputs
(Zone.diff inputs data.under_outputs)}
| _ -> data