HP aC++/HP C A.06.25 Programmer's Guide

The +O[no]store_ordering 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.

+Otype_safety

+Otype_safety=kind

The +Otype_safety option controls type-based aliasing assumptions.

The defined values for kind are:

off

The default. Specifies that aliasing can occur freely across types.

limited

Code follows ANSI aliasing rules. Unnamed objects should be treated as

if they had an unknown type.

ansi

Code follows ANSI aliasing rules. Unnamed objects should be treated the

same as named objects.

strong Code follows ANSI aliasing rules, except that accesses through lvalues

of a character type are not permitted to touch objects of other types and

field addresses are not to be taken.

The default is +Otype_safety=off.

+Ounroll_factor

+Ounroll_factor=n

The +Ounroll_factor option applies the unroll factor to all loops in the current

translation unit. You can apply an unroll factor which you think is best for the given

loop or apply no unrolling factor to the loop. If this option is not specified, the compiler

uses its own heuristics to determine the best unroll factor for the inner loop.

A user specified unroll factor will override the default unroll factor applied by the

compiler.

Specifying n=1 will prevent the compiler from unrolling the loop.

Specifying n=0 allows the compiler to use its own heuristics to apply the unroll factor.

NOTE: This option will be ignored if it is placed in a loop other than the innermost

loop.

+O[no]whole_program_mode

The +O[no]whole_program option enables the assertion that only those files that

are compiled with this option directly reference any global variables and procedures

that are defined in these files. In other words, this option asserts that there are no unseen

accesses to the globals.

86 Command-Line Options