It is highly recommended that you uninstall any previous versions of XL C/C++ before you install XL C/C++ V8.0. If you use the xlc_install utility to install the new version to the default location (/opt/ibmcmp/), it will remove the old files for you.
However, advanced users might want to keep different versions of XL C/C++ in /opt/ibmcmp/.
For example, you might want to meet all of the following criteria: