Program performance improves if your loop control variables are one of the types in the following list. You should rarely, if ever, use other types of variables.
Performance also improves if loop control variables are not members of arrays, structures, or unions. The compiler issues a warning message when they are. Loop control variables that are AUTOMATIC and not used for any other purpose give you the optimal code generation.
If a loop control variable is a FIXED BIN, performance is best if it has precision 31 and is SIGNED.
Performance is decreased if your program depends not only on the value of a loop control variable, but also on its address. For example, if the ADDR built-in function is applied to the variable or if the variable is passed BYADDR to another routine.