HP Fortran Programmer's Guide (March 2010)

Performance and optimization
Using options to control optimization
Chapter 6 155
Table 6-3 Fine-tuning optimization options
Option Level Function
+O[no]cache_pad_common +O3 or
higher
Pad [do not pad] common blocks to avoid
cache collisions. The default is
+Onocache_pad_common.
+O[no]dataprefetch +O2 or
higher
Insert [do not insert] instructions within
innermost loops to explicitly prefetch data
from memory into the data cache. The
default is +Onodataprefetch.
+O[no]dynopt All 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 system-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.
+O[no]entrysched All Perform [do not perform] instruction
scheduling on entry and exit code. The
default is +Onoentrysched.
+O[no]fastaccess All Enable [disable] fast access to global data.
The default is +Onofastaccess at levels 1,
2, and 3; +Ofastaccess at level 4.