Diving Into GCC: OpenBSD and m88k
BSD Forums writes "This OnLamp article by Miod Vallat describes how the m88k-specific backend of the GNU C compiler, gcc, was fixed, from the discovery and analysis of the problems to the real fixing work. Since it started with almost zero gcc internals knowledge, it should be understandable by anyone able to read C code, and proves that diving into gcc is not as hard as one could imagine."
It is interesting to note that every OpenBSD software, including OpenBSD itself, requires a Red Hat product, in fact owes its practical existence to Red Hat GCC.