| a program’s behavior. This option is only effective at | |
| optimization level 2 or higher. | |
| The +Oaggressive option performs optimizations invoked | |
| by the following options: | |
| • | +Oentrysched |
| • | +Olibcalls |
| • | +Onofltacc |
| • | +Onoinitcheck |
| • | +FPD |
| +FPD is enabled only if +Oaggressiveis used on the | |
| link line. | |
|
| |
| NOTE: The +Oaggressive option is incompatible with | |
| +Oconservative. | |
| The default is +Onoaggressive. | |
|
| |
| NOTE: This option is only valid on the | |
|
| |
+O[no]all | +Oall performs maximum optimization, including | |
| aggressive optimizations and optimizations that can | |
| significantly increase compile time and memory usage. | |
| The +Oall option automatically invokes the highest level | |
| of optimization. | |
| The default is +Onoall. | |
| This option has been deprecated on version | |
| and later. | |
|
| |
+O[no]autopar | +O[no]autopar controls automatic parallelization of | |
| loops that are deemed safe and profitable by the loop | |
| parallelizer. | |
| The | |
| the idle resources on multicore or multiprocessor systems, | |
| by automatically | |
| The +Oautopar option can be used for programs at | |
| optimization levels, +O3and above. If both +Oopenmpand | |
| +Oautopar are specified on the command line, the | |
| OpenMP directives gain precedence over the +Oautopar | |
| option. The compiler | |
| code that are not controlled by the OpenMP directives. | |
| On HP 9000 systems, when +Oautopar is used with the | |
| +Oparalleloption, +O4is inhibited. If automatic | |
| parallelization is desired along with +O4, then use | |
| +Oautopar and omit +Oparallel. | |
| To compile a program with +Oautopar support, the | |
| libcps, libomp, and libpthreadsruntime support | |
| libraries must be present at | |
| feature is available on | |
| 9000 systems. | |
| The +Oconservativeoption sets the following options: | |
| • | +Ofltacc |
| • | +Onofltacc |
| • | +Onomoveflops |
| • | +Oparmsoverlap |
| Use +Oconservative when conservative assumptions | |
| are necessary due to the coding style, as with | |
| ||
| incompatible with +Oaggressive. | |
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Reviewing general optimization options | 39 |