+O[no]loop_transform | +Oloop_transformenables transformation of eligible |
| loops for improved cache performance. The most |
| important transformation is the interchange of nested |
| loops to make the inner loop unit stride, resulting in fewer |
| cache misses. +Onoloop_transform disables |
| transformation of eligible loops. The default is |
| +Oloop_transform. |
| NOTE: This option is deprecated and not supported in |
| future releases. Use +inline_level. |
+inline_level num | This option controls inlining in fortran. The format for num |
| is N[.n], where num is either an integral value from0 |
| to 9 or a value with a single decimal place from 0.0to |
| 9.0. For more information on this option, see |
| F90(1)manpage. |
+O[no]loop_unroll[=factor] | +Oloop_unrollturns on loop unrolling. factor is the |
| unroll factor that controls the code expansion. The default |
| unroll factor is 4; that is, four copies of the loop body. |
| By experimenting with different factors, you may improve |
| the performance of your program. This option is only |
| effective at optimization level 2 or higher. The default is |
| +Oloop_unroll=4. |
+O[no]loop_unroll_jam | +loop_unroll_jamenables loop unrolling and |
| jamming. +Onoloop_unroll_jam (the default) disables |
| both automatic and |
| Loop unrolling and jamming increases register |
| exploitation. |
+O[no]moveflop | +Omoveflops allows the optimizer to move conditional |
| |
| to occur. This option is only effective at optimization level |
| 2 or higher. |
| The behavior of |
| be altered by this option. |
| Using +Onomoveflops is recommended if |
| traps are enabled and you do not want the behavior of |
| |
| of |
| the ON statement. The default is +Omoveflops. |
+Oprefetch | +Omultiprocessortells the compiler to appropriately |
| optimize several different processes on multiprocessor |
| machines. The optimizations are those appropriate for |
| executables and or shared libraries. |
| +Onomultiprocessor, the default, disables the |
| optimization of more than one process running on a |
| multiprocessor machine. |
| NOTE: This option is valid only on the |
+O[no]openmp | +Oopenmp allows users to enable the OpenMP directives. |
| +Onoopenmpwill disable the OpenMP directives. |
| +O[no]openmpis accepted at all optimization levels. |
| The default is +Onoopenmp. |
+O[no]parallel | +Oparallel causes the compiler to transform eligible |
| loops for parallel execution on multiprocessor machines. |
| This option is effective only at optimization level 3 or |
| higher. This option is available only on HP 9000 systems. |
| If you link separately from the command line and compile |
| the program with the +Oparallel option, you must link |
| with the f90 command and specify the |
| +Oparalleloption to link in the correct runtime support. |
| The +Onoparallel option disables parallelization for |
| the target program. It is the default at all levels of |
| optimization. The +Oparallel option is not available |
46 Compiling and linking