When OPTIMIZATION is in effect, conditions for the same expression that appear multiple times can be raised only once. In the following example, SUBSCRIPTRANGE for IX can be raised only once:
call P (55);
(subscriptrange): P: proc (IX);
dcl (Ar, Br, Cr) (10);
Ar(IX) = Ar(IX) + Br(IX);
T = Cr(IX);
End P;