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

Compiling and linking
Compiling with the f90 command
Chapter 2 75
+O[no]regreassoc
+Onoregreassoc disables register reassociation. This option is only effective at
optimization level 2 or higher.
Use +Onoregreassoc to disable register reassociation in the rare case that this
optimization degrades performance.
+Oregreassoc is the default.
NOTE This option is valid only on the PA-RISC systems.
+O[no]report +Oreport specifies the contents of the Optimization Report.
+Oshortdata[=size]
All objects of size bytes or smaller will be placed in the short data area, and references
to such data will assume it resides in the short data area. Valid values of n are 0, or a
decimal number between 8 and 4,194,304 (4MB). If no size is specified, all data is
placed in the short data area. If size is 0, no data will be placed in the short data area,
and all data references will use long offsets.
The default is +Oshortdata=8.
NOTE Using a value that is too big or without the optional size, possibly
through +Ofast, may give various linker fixup errors, if there is more
than 4Mb of short data.
NOTE All object files participating in a link need to be consistently compiled
with respect to +Oshortdata. Since the +Ofaster and +Ofast
options imply +Oshortdata, other Fortran object files which
reference common blocks should also be explicitly compiled with
+Oshortdata. Alternatively, the +Ofaster and +Ofast
compilations can be compiled with an additional +Oshortdata=8
appended to the command line.
+O[no]sideeffects=name1, name2,...nameN
Optimize with the assumption that the specified subprograms do [do not] modify global
variables. This option can be used at optimization level 2 or higher. The default is to
assume that all subprograms have side effects unless the optimizer can determine that
there are none.