HP Fortran Programmer's Guide (September 2007)

Compiling and linking
Compiling with the f90 command
Chapter 260
• +Onofltacc
• +Onoinitcheck
• +Ovectorize
The +Oaggressive option is incompatible with +Oconservative.
The default is +Onoaggressive.
+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 HP-UX 11i and later.
+O[no]autopar
+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
transforming the serial loops of code in the program into multithreaded
parallel code.
The +Oautopar option can be used for programs at optimization levels, +O3
and above. If both +Oopenmp and +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 +Oparallel option,
+O4 is 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
libpthreads runtime support libraries must be present at compile-time
and runtime. This feature is available on Integrity systems and HP 9000
systems.
+O[no]conservative