Summary of Optimization Parameters

+O[no]aggressive

The +O[no]aggressive option enables optimizations that can result in significant performance improvement, but that can change a program's behavior. These optimizations include newly released optimizations and the optimizations invoked by the following advanced optimization options: ^[1]

The default is +Onoaggressive.

+O[no]all

The +Oall option performs maximum optimization, including aggressive optimizations and optimizations that can significantly increase compile time and memory usage. The default is +Onoall.

4

+O[no]conservative

The +O[no]conservative option causes the optimizer to make conservative assumptions about the code when optimizing it. Use +Oconservative when conservative assumptions are necessary due to the coding style, as with non-standard conforming programs. The +Oconservative option relaxes the optimizer's assumptions about the target program. The default is +Onoconservative.

+O[no]info

+Oinfo displays informational messages about the optimization process. This option supports the core optimization levels, and therefore, can be used at levels 0-4. The default is +Onoinfo.

0, 1, 2, 3, 4

+O[no]limit

The +Olimit option suppresses optimizations that significantly increase compile-time or that can consume a lot of memory. The +Onolimit option allows optimizations to be performed regardless of their effect on compile-time or memory usage. The default is +Olimit.

2, 3, 4

+O[no]size

The +Osize option suppresses optimizations that significantly increase code size. The +Onosize option does not prevent optimizations that can increase code size. The default is +Onosize.

2, 3, 4