If the compiler is installed to a non-default location, you have to remove the filesets yourself.
To uninstall the XL C/C++ compiler installed to a non-default location, delete the compiler directory.
To determine which version of each fileset is installed, see Checking compiler and fileset information.
rm -rf target_dirwhere target_dir is the target directory for installation specified by the -b option of the non-default installation script.