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

Performance and optimization
Using options to control optimization
Chapter 6 159
+O[no]recovery All This option generates [does not generate]
recovery code for control speculation. For code
that writes to uncacheable memory that may not
be properly identified as volatile, the +Orecovery
option reduces the risk of incorrect behavior. The
default is +Orecovery.
NOTE:
The program that uses signal handlers to catch
signals raised by memory accesses may not
behave correctly under +Onorecovery.
+O[no]regreassoc +O2 or higher Enable [disable] register association. The default
is +Oregreassoc.
NOTE: This option is valid only on the PA-RISC
systems.
+Ono_return All This option provides a hint to the optimizer that
the named functions never return to the call site.
If the +Ono_return:filename form is used,
the file filename contains a list of function names
separated by spaces or newlines. This
optimization is available at all optimization
levels.
+Oshortdata[=size] All All objects of size bytes or smaller are placed in
the short data area, and references to such data
assume it resides in the short data area. Valid
values of size are a decimal number between 8
and 4,194,304 (4MB). If no size is specified, all
data is placed in the short data area.
The default is +Oshortdata=8.
Table 6-3 Fine-tuning optimization options (Continued)
Option Level Function