HP Fortran Programmer Guide HP-UX 11i v1, HP-UX 11i v2, and HP-UX 11i v3 (B3908-90032,December 2012)

The +Oalloption automatically invokes the highest level
of optimization.
The default is +Onoall.
This option has been deprecated on version HP-UX 11i
and later.
+O[no]autoparcontrols automatic parallelization of loops
that are deemed safe and profitable by the loop
parallelizer.
The auto-parallelization feature enables applications to use
the idle resources on multicore or multiprocessor systems,
by automatically
+O[no]autopar
The +Oautoparoption 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 auto-parallelizes only the loops of
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 compile-time and runtime. This
feature is available on Itanium®-based systems and HP
9000 systems.
The +Oconservativeoption sets the following options:
• +Ofltacc
• +Onofltacc
• +Onomoveflops
• +Oparmsoverlap
Use +Oconservativewhen conservative assumptions
are necessary due to the coding style, as with
nonstandard-conforming programs. Note that it is
incompatible with +Oaggressive.
The +Onoconservativeoption relaxes the optimizer’s
assumptions about the target program.
The +Onoconservativeoption relaxes the optimizer’s
assumptions about the target program.
The default is +Onoconservative. This option has been
deprecated starting with HP-UX version 11i and later.
+Olimitsuppresses optimizations that significantly
increase compilation time or that can consume large
+O[no]limit
amounts of memory at compile time. This option is only
effective at optimization level 2 or higher.
The +Onolimitoption allows optimizations to be
performed regardless of their effect on compilation time or
memory usage. The default is +Olimit.
Enables [disables] the following transformations: loop unroll
and jam, loop distribution, loop interchange, loop blocking,
+O[no]loop_transform
loop fusion, and loop unroll. The default is
+Oloop_transform.
+Osizesuppresses optimizations that significantly increase
code size. This option is only effective at optimization level
+O[no]size
2 or higher. The +Onosize option permits optimizations
that can increase code size. The default is +Onosize.
38 Compiling and linking