HP Fortran Programmer's Guide (March 2010)

Performance and optimization
Using options to control optimization
Chapter 6 159
+O[no]loop_unroll_jam +O3 or
higher
Loop unroll-and-jam involves partially
unrolling one or more loops higher in the
nest than the innermost loop, and fusing
("jamming") the resulting loops back
together. This transformation is primarily
intended to increase register reuse and
decrease memory loads and stores per
operation within an iteration of a nested
loop.
+moduleoptimize All The compiler reads only required
information from a module file. Optimized
module files are created by discarding
redundant information while importing
the module file. In case of nested modules
or hierarchical modules, the compilation
time and memory requirement of compiler
can be reduced by using this option.
+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]parminit All This option enables [disables] automatic
initialization to non-NaT of unspecified
function parameters at call sites. This is
useful in preventing NaT values in
parameter registers. The default is
+Onoparminit.
Table 6-3 Fine-tuning optimization options (Continued)
Option Level Function