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

NOTE: Compiling with this optimization setting may require additional memory

resources. Refer to the memory resource discussion above.

Example:

This command compiles prog.C and optimizes at level 4:

aCC +O4 prog.C

If you run out of memory when compiling at +O4 optimization, there are several things

you can do:

• Compile at +O4 only those modules that need to be compiled at optimization level

4, and compile the remaining modules at a lower level.

• If you still run out of memory, increase the per-process data size limit. Run the

System Administrator Manager (SAM) to increase the maxdsiz_64bit process

parameter to more than 4GB. This procedure provides the process with additional

data space.

• If increasing the per-process data size limit does not solve the problem, increase

the system swap space.

Refer to the System Administration Tasks manual for more information.

Object Files Generated at Optimization Level 4

Object files generated by the compiler with +O4 or -ipo, called intermediate object

files, are intended to be temporary files. These object files contain an intermediate

representation of the user code in a format that is designed for advanced optimizations.

The size of these intermediate object files can typically be 3 to 10 times as large as

normal object files. Hewlett-Packard reserves the right to change the format of these

files without prior notice. There is no guarantee that intermediate object files will be

compatible from one revision of the compiler to the next. Use of intermediate files must

be limited to the compiler that created them. For the same reason, intermediate object

files should not be included into archived libraries that might be used by different

versions of the compiler. The compiler will issue an error message and terminate when

an incompatible intermediate file is generated.

Additional Optimization Options for Finer Control

Following are the additional optimizations options for finer control:

+ES[no]lit

The +ES[no]lit option places [does not place] string literals and const-qualified

variables that do not require load-time or runtime initialization in the read-only data

section. This is the same as using the +Olit option.

Code Optimizing Options 71