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       },...)]
                      {TUNE={GENERIC}}
                            {HOST   }

   where:

      LEVEL=n        controls   the   amount   of   optimization   performed.
                     /OPTIMIZE=LEVEL=4 is the equivalent of /OPTIMIZE.

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

           1              local  optimizations   and   common   subexpression
                          recognition turned on.

           2              adds  some  global  optimizations  including   loop
                          unrolling,  split  lifetime  analysis, code motion,
                          and code scheduling to those in level 1.

           3              adds more global optimizations that  improve  speed
                          (at  the  cost of extra code size), such as integer
                          multiplication  and   division   expansion   (using
                          shifts),  loop  unrolling,  and code replication to
                          eliminate branches to those in level 2.

           4              adds automatic inline expansion of  procedures  and
                          functions to those of level 3.  This is the default
                          level.

      TUNE=processor selects  processor-specific  instruction  tuning  for  a
                     specific  implementation  of  the  Itanium architecture.
                     Tuning  for  a  specific  implementation   can   provide
                     improvements in run-time performance.

                     Regardless of  the  setting  of  the  TUNE  option,  the
                     generated code will run correctly on all implementations
                     of the Itanium architecture.  Note that code tuned for a
                     specific  target  may  run more slowly on another target
                     than generically-tuned code.

                     Also see the /ARCHITECTURE qualifier.

                     TUNE=GENERIC is the default.

                     The processor keyword can be one of the following:

           GENERIC        selects instruction tuning that is appropriate  for
                          all  implementations  of  the Itanium architecture.
                          This option is the default.

           HOST           selects instruction tuning that is appropriate  for
                          the machine on which the code is being compiled.

           ITANIUM2       selects  instruction  tuning   for   the   Itanium2
                          implementation of the Itanium architecture.

           MERCED         selects   instruction   tuning   for   the   Merced
                          implementation of the Itanium architecture.

   The default is /OPTIMIZE=(LEVEL=4, TUNE=GENERIC).