> As I didn't get any further followups on this topic, I looked at the
> bytecode compiler and interpreter.  (As of Ocaml 2.01) I cannot see
> the "function application" case being done:

All function application instructions (APPLY*) perform a check for signal.
The CHECK_SIGNAL instruction is needed only when a check must be
performed elsewhere (i.e. at the head of a loop body).

- Xavier Leroy