HP aC++/HP C Programmer's Guide (B3901-90036; A.06.26; September 2011)

+O[no]loop_unroll

+O[no]loop_unroll [=unroll_factor]

The +O[no]loop_unroll option enables [disables] loop unrolling. This optimization

can occur at optimization levels 2, 3, and 4. The default is +Oloop_unroll. The default

is 4, that is, four copies of the loop body. The unroll_factor controls code expansion.

Note that +Onoloop_unroll has no effect on loop unroll-and-jam.

+O[no]openmp

The +Oopenmp option causes the OpenMP directives to be honored. This option is

effective at any optimization level. Non OpenMP parallelization directives are ignored

with warnings. +Onoopenmp requests that OpenMP directives be silently ignored. If

neither +Oopenmp nor +Onoopenmp is specified, OpenMP directives will be ignored

with warnings.

The OpenMP specification is available at http://www.openmp.org/specs. OpenMP

programs require the libomp and libcps runtime support libraries to be present on

both the compilation and runtime systems. The compiler driver automatically includes

them when linking.

If you use +Oopenmp in an application, you must use -mt with any files that are not

compiled with +Oopenmp. For additional information and restrictions, See “-mt” (page 79).

It is recommended that you use the -N option when linking OpenMP programs to avoid

exhausting memory when running with large numbers of threads.

NOTE: HP aC++ version A.06.00 does not support C++ constructs in OpenMP. Use

the +legacy_v5 option to use this option.

+opts

+opts filename

The file indicated by filename contains a list of options that are processed as if they

had been specified on the command line at the point of the +opts option. The options

must be delimited by a blank character. You can add comments to the option file by

using a "#" character in the first column of a line. The "#" causes the entire line to be

ignored by the compiler.

Example:

$ aCC +opts GNUOptions foo.c

Where GNUOptions contains:

#This file contains the set of options for programs needing GNU support -Ag++ -Wc,--fshort-enums

+O[no]parminit

74 Command-Line Options