HP C/aC++ for PA-RISC Software manual Advanced +Ooptimization Options, +Onoaggressive, +Onolimit

+O[no]aggressive

+O[no]aggressive

The +Oaggressive option enables aggressive optimizations. The +Onoaggressive option disables aggressive optimizations.

By default, aggressive optimizations are turned off. The +Oaggressive option is approximately equivalent to +Osignedpointers +Onoinitcheck +Ofltacc=relaxed.

NOTE: This option is deprecated and may not be supported in future releases. Instead you can use +Ofastoption.

+O[no]limit

+O[no]limit

The +Olimit option enables optimizations that significantly increase compile time or that consume a lot of memory.

The +Onolimit option suppresses optimizations regardless of their effect on compile time or memory consumption.

Use +Onolimit at all optimization levels.

Usage:

+O[no]limit=level

The defined values of level are:

default	Based on tuning heuristics, the optimizer will spend a reasonable amount of time
	processing large procedures. This is the default option.
min	For large procedures, the optimizer will avoid non-linear time optimizations. This
	option is a synonym for +Olimit.
none	The optimizer will fully optimize large procedures, possibly resulting in significantly
	increased compile time. This option is a synonym for +Onolimit.

Example:

To remove optimization time restrictions at O2, O3, or O4 optimization levels, use +Onolimit as follows:

aCC <opt level> +Onolimit sourcefile.C

+O[no]ptrs_to_globals[=list]

+O[no]ptrs_to_globals[=list]

The +O[no]ptrs_to_globals option tells the optimizer whether global variables are accessed [are not accessed] through pointers. If +Onoptrs_to_globals is specified, it is assumed that statically-allocated data (including file-scoped globals, file-scoped statics, and function-scoped statics) will not be read or written through pointers. The default is +Onoptrs_to_globals.

+O[no]size

+O[no]size

While most optimizations reduce code size, the +Osize option suppresses those few optimizations that significantly increase code size. The +Onosize option enables code-expanding optimizations.

Use +Osize at all optimization levels. The default is +Onosize.

Advanced +Ooptimization Options

Advanced optimization options provide additional control for special situations.

Code Optimizing Options 57