The /OPTIMIZE  qualifier  controls  whether  the  compiler  optimizes  the
   program to generate more efficient code for optimum run-time performance.

   The format of the /OPTIMIZE qualifier is as follows:

      /[NO]OPTIMIZE[=LEVEL=n]

   The following list describes the level options:

      Level 0        Has the same effect as /NOOPTIMIZE.   All  optimizations
                     are turned off.

      Level 1        Has some optimizations (such as instruction scheduling).

      Level 2        Adds more optimizations  (such  as  loop  unrolling  and
                     split lifetime analysis) to those in level 1.

      Level 3        Adds more optimizations.

      Level 4        Is the default level.

   /OPTIMIZE=LEVEL=4 is the equivalent of /OPTIMIZE

   The default is /OPTIMIZE.