HP UX Fortran Software manual +Oregreassoc, +Onoreturn, +Oshortdata=8, +Ovectorize option on

Table 29 Fine-tuning optimization options (continued)

Level	Level	Function
+O[no]regreassoc	+O2or higher +O2or 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:filenameform
		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.
+[no]srcpos	All	This option controls the
		generation of source position
		information for HP Caliper.
		The default is +srcpos.
		When +srcpos, is in effect,
		the compiler generates
		source position information.
		When+nosrcposis in
		effect, the compiler does not
		generate this information
		and the compiler instructs the
		linker to discard any of this
		information found in the
		object files.
+O[no]store_ordering	All	This option preserves [does
		not preserve] the original
		program order for stores to
		memory that is visible to
		multiple threads. This does
		not imply strong ordering.
		The default is
		+Onostore_ordering.
+O[no]vectorize	+O3or higher	Replace [do not replace]
		eligible loops with calls to
		the math library; for more
		information, see “Using the
		+Ovectorizeoption” on
		page168. The default
		is+Onovectorize.

98 Performance and optimization