HP Fortran Programmer's Guide (B3908-90031; September 2011)

Compiling and linking
Compiling with the f90 command
Chapter 2 65
The default is +Onocxlimitedrange.
+O[no]cross_region_addressing
Enable [disable] the use of cross-region addressing. Cross-region addressing is required
if a pointer (such as an array base) points to a different region than the data being
addressed. This is usually due to an offset which results in a cross-over into another
region. Standard-conforming applications do not require the use of cross-region
addressing.
The default is +onocross_region_addressing.
+O[no]dataprefetch
+Odataprefetch causes the optimizer to insert instructions within innermost loops to
explicitly prefetch data from memory into the data cache. Data prefetch instructions
will be inserted only for data structures referenced within innermost loops using simple
loop varying addresses—that is, in a simple arithmetic progression. It is not available
for PA-RISC 1.1 targets.
Use this option for applications that have high data cache miss overhead.
The default is +Onodataprefetch. On HP-UX version 11i and later,
+Odataprefetch is the same as +Odataprefetch=indirect and
+Onodataprefetch is the same as +Odataprefetch=none. At +O2 and higher,
the default is +Odataprefetch.
+O[no]dataprefetch=[direct|indirect|none]
Control generation of data prefetch instructions for data structures referenced within
innermost loops. The defined values for kind are:
direct—enable generation of data prefetch instructions for the benefit of direct
memory accesses, but not indirect memory accesses.
indirect—enable generation of data prefetch instructions for the benefit of both
direct and indirect memory accesses. This is the default at optimization levels +O2 and
above.
none—disable generation of data prefetch instructions. This is the default at
optimization levels +O1 and below.
+O[no]dynopt
Enable [disable] dynamic optimization for the output file, if the run-time environment
supports this feature. Both forms of this option change the default setting, which allows
the run-time environment to enable or disable dynamic optimization according to a