HP Fortran Programmer's Guide (September 2007)

Performance and optimization
Using options to control optimization
Chapter 6150
+Oinline_budget= n +O3 or
higher
Perform more aggressive inlining, as
specified by n . The default is
+Oinline_budget=100.
+O[no]libcalls All Substitute [do not substitute] millicode
versions of specific intrinsics. The default
is +Olibcalls.
+O[no]loop_unroll= n +O2 or
higher
Unroll [do not unroll] program loops by a
factor of n . The default is
+Oloop_unroll=4.
+O[no]moveflops +O2 or
higher
Enable [disable] moving conditional
floating-point instructions out of loops.
The default is +Omoveflops.
+O[no]parallel +O3 or
higher
Transform [do not transform] eligible loops
for parallel execution. The default is
+Onoparallel.
This option is available only on HP 9000
systems. On Integrity systems, you can use
the +Oautopar option instead to parallelize
loops.
+O[no]parmsoverlap +O2 or
higher
Suppress optimizations that assume [do
not assume] that arguments may refer to
the same memory locations. The default is
+Onoparmsoverlap.
+O[no]pipeline +O2 or
higher
Enable [disable] software pipelining. The
default is +Opipeline.
+O[no]procelim All Remove [do not remove] unreferenced
procedures from the executable. The
default is +Onoprocelim at levels 0 - 3,
+Oprocelim at level 4.
+O[no]regreassoc +O2 or
higher
Enable [disable] register association. The
default is +Oregreassoc.
Table 6-3 Fine-tuning optimization options (Continued)
Option Level Function