Removing Compilation Time Limits When Optimizing

You can remove optimization time restrictions at the second, third, or fourth optimization levels by using the +Onolimit option as follows:

cc +O2 +Onolimit sourcefile.c

or:

cc +O3 +Onolimit sourcefile.c

or:

cc +O4 +Onolimit sourcefile.c

By default, the optimizer limits the amount of time spent optimizing large programs at levels 2, 3, and 4. Use this option if longer compile times are acceptable because you want additional optimizations to be performed.