I post this not as a bug report but more FYI (in particular the compiler developers).
I tried ifc 7.1 on Rh severn beta (which presumably will become RH10 in October). Using the following compiler options (for P4) -O2 -tpp7 -xiMKW I ran into multiple internal compiler errors and often the compilation of a source file would never finish. This of course is all code that so far compiled just fine. I found that -O2 -tpp7 still works and I was able to link with the -i_dynamic option.
It remains to be seen if this will improve until the final release.
I actually would like to use even this beta because it works great on my laptop, something RH so far was not famous for.