HP Fortran Programmer Guide (766160-001, March 2014)

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 PA-RISC systems.
+Oall performs maximum optimization, including
aggressive optimizations and optimizations that can
+O[no]all
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 HP-UX 11i
and later.
+O[no]autopar controls 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 +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 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 +Oconservative when conservative assumptions
are necessary due to the coding style, as with
nonstandard-conforming programs. Note that it is
incompatible with +Oaggressive.
Reviewing general optimization options 39