HP aC++/HP C A.06.20 Programmer's Guide

This optimization will not be performed if the copy-constructor was not declared by

the programmer. Note that although this optimization is allowed by the ISO/ANSI C++

standard, it may have noticeable side effects.

Example:

aCC -Wc,-nrv_optimization,on app.C

+O[no]failsafe

The +O[no]failsafe option enables [disables] failsafe optimization. When a

compilation fails at the current optimization level +Ofailsafe will automatically

restart the compilation at +O2 (for specific high level optimizer errors +O3/+O4), O1,

or +O0.

The default is +Ofailsafe.

+O[no]all

Use the +Oall option to obtain the best possible performance. This option should be

used with stable, well-structured code. These optimizations give you the fastest code,

but are riskier than the default optimizations.

You can use +Oall at optimization levels 2, 3, and 4. The default is +Onoall.

This option is deprecated and may not be supported in future releases. Instead you

can use +Ofaster. +O4 +Onolimit +Oaggressive is approximately equivalent

to +Oall.

+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 +Olibcalls +Onoinitcheck

+Ofltacc=relaxed.

NOTE: This option is deprecated and may not be supported in future releases. Instead

you can use +Ofastoption.

+O[no]conservative

The +O[no]conservative option is deprecated and may not be used in future

releases. It is approximately equivalent to +Oparmsoverlap +Onomoveflops.

Code Optimizing Options 71