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

NOTE: This option is valid only on the PA-RISC systems.
Applies to loops for which the compiler generates data
prefetch instructions. For a given loop, the compiler
+Oprefetch_latency=num option
divides “cycles” by the estimated loop length to arrive
at the number of loop iterations for which to generate
advance prefetches. The default value is 480 cycles for
loops containing floating-point accesses and 150 cycles
for loops that do not contain any floating-point accesses.
For tuning purposes, it is recommended that users
measure their application’s performance using a few
different prefetch latency settings to determine the optimal
value. Some floating-point codes may benefit by
increasing the distance to 960. Parallel applications
frequently benefit from a shorter prefetch distance of 150.
When +Oprocelimis specified, procedures that are not
referenced by the application are eliminated from the
+O[no]procelim
output executable file. When +Onoprocelimis specified,
procedures that are not referenced by the application
are not eliminated from the output executable file. You
can use this option at any level of optimization.
Use +Oprocelimto reduce the size of the executable
file, especially when optimizing at levels 3 and 4, when
inlining can remove all calls to some routines.
The default is +Onoprocelimat levels 0-3, and
+Oprocelimat level 4.
Specify filname as the name of the profile database file.
This option is a synonym for the +P, +dffilename
+Oprofile=use:filename
options.The :filename argument is optional (the default
filename is flow.data). See ld (1), +P, and +df for
more details. This option is only valid for Itanium®-based
applications.
In the absence of qualifiers, +Oprofile=collectis
the same as +I.
&lt qualifiers &gt are a comma-separated list of profile
collection qualifiers. Supported profile collection qualifiers
are :
+Oprofile=collect&ltqualifiers&gt
arc—collect arc counts (synonym to
+Oprofile=collect). This is the default value.
stride—collect stride data.
all—collect all types of profile data. This is a synonym
for +Oprofile=collect:arc,stride
+Oprofile=collect:arc,stride
+Oprofile=collectinstruments the application for
profile-based optimization.
This option is only valid for Itanium®-based applications.
Enable [disable} the promotion of indirect calls to direct
calls. Indirect calls occur with pointers to functions. This
+O[no]promote_indirect_calls
option can be used at optimization levels 3 and 4. The
default is +Onopromote_indirect_calls.
Tells the optimizer whether global variables are modified
[are not modified] through pointers. This optimization
+O[no]ptrs_to_globals[=name1,name2,...,nameN]
can occur at levels 2, 3, and 4. The default is
+Optrs_to_globals.
The named functions are assumed to be infrequently
called. This option overrides any information in a profile
database.
+Orarely_called=function1[,function2...]
The file indicated by filename contains a list of function
names, separated by spaces or newlines. These functions
+Orarely_called:filename
46 Compiling and linking