The SDK used the compiler from the IDO 5.3 package which was provided by SGI for developing in IRIX 5.3 (if you paid the extra for that option). I think by the

The SDK used the compiler from the IDO 5.3 package which was provided by SGI for developing in IRIX 5.3 (if you paid the extra for that option). I think by then it would have already been pretty mature.