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

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, +Odataprefetchis the same as
+Odataprefetch=indirectand
+Onodataprefetchis the same as
+Odataprefetch=none.At +O2and higher, the
default is +Odataprefetch.
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.
+O[no]dataprefetch=[direct|indirect|none]
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 +O1and below.
Enable [disable] dynamic optimization for the output
file, if the run-time environment supports this feature.
+O[no]dynopt
Both forms of this option change the default setting,
which allows the run-time environment to enable or
disable dynamic optimization according to
asystem-wide default. This option applies only to
executable files and shared libraries. chatr(1)can
be used to change this setting, including restoration
of the default setting, after the output file has been
created.
+Oentryschedallows the optimizer to perform
instruction scheduling on a subprogram’s entry and
+O[no]entrysched
exit code sequences. This option is only effective at
optimization level 1 or higher.
The option can change the behavior of programs that
perform exception-handling or that handle
asynchronous interrupts.
The default is +Onoentrysched.
NOTE: This option is valid only on the PA-RISC
systems.
Enable [disable] failsafe optimization. When a
compilation fails at the current optimization level,
+O[no]failsafe
+Ofailsafe will automatically restart the compilation
at +O2(for specific high level optimizer errors
+O3/+O4) or +O1for Itanium® processor family
architecture and +O0for PA-RISC architecture. The
default is +Ofailsafe.
Select a combination of compilation options for
optimum execution speed of the compiled program.
+Ofast
Those options include: +O2,
+Olibcalls+Onolimit, +Ofltacc=relaxed,
and +FPD. +Ofast also causes the +pi4M,
+pd4Moptions to be passed to the linker. In addition
to these options, on the Itanium processor family
architecture, +DSnative instruction scheduling is
selected and +mergesegis also passed to the linker.
40 Compiling and linking