The NORESEXP compiler option will increase the compatibility of your code if your code intentionally forces a ZERODIVIDE condition:
The RESEXP compiler option allows the compiler to evaluate all restricted expressions at compiler time. For example, programs with the following code would fail at compile-time with an S-level message:
if somevariable = goodvalue then;
else
put skip list( 1 / 0 );
Under the NORESEXP compiler option, the compiler would not flag this statement and the ZERODIVIDE condition would be raised at run-time, as originally intended.