Table 29 Fine-tuning optimization options (continued)

Level

Level

Function

 

 

NOTE: Do not use this

 

 

option for programs that

 

 

depend on IEEE standard

 

 

floating point denormalized

 

 

numbers. Otherwise,

 

 

different numerical results

 

 

may occur. See

 

 

+Ofltacc=relaxed. This

 

 

option is a synonym for

 

 

-fast.

 

 

 

+Ofaster

All

This option is equivalent to

 

 

+Ofastwith an increased

 

 

optimization level. The

 

 

definition of +Ofastermay

 

 

change or it may be

 

 

deprecated in future

 

 

releases.

 

 

 

+O[no]fltacc

+O2or higher

Disable [enable]

 

 

floating-point optimizations

 

 

that can result in numerical

 

 

differences. By default, the

 

 

optimizer does not perform

 

 

such optimizations. For

 

 

information about the effect

 

 

this option can have on your

 

 

program, see the HP-UX

 

 

Floating-Point Guide.

 

 

 

+Ofrequently_called=function1[,function2...]

All

The named functions are

 

 

assumed to be frequently

 

 

called. This option overrides

 

 

any information in a profile

 

 

database.

 

 

 

+Ofrequently_called:filename

All

The file indicated by

 

 

filename contains a list of

 

 

functions, separated by

 

 

spaces or newlines. These

 

 

functions are assumed to be

 

 

frequently called. This option

 

 

overrides any information in

 

 

a profile database.

 

 

 

+O[no]info

All

Display [do not display]

 

 

information about the

 

 

optimization process. This

 

 

option is most useful at level

 

 

3 and above. The default is

 

 

+Onoinfo.

 

 

 

+O[no]initcheck

+O2or higher

Enable [disable]

 

 

initialization of any local,

 

 

scalar, automatic variable

 

 

that is found to be

 

 

uninitialized. The default is

 

 

to initialize if the variable is

 

 

uninitialized with respect to

 

 

every path leading to its use.

 

 

For more information about

 

 

this option, see

 

 

“Uninitialized variables”

 

 

(page 144).

94 Performance and optimization