I finally got cc1/alpha to 'fess up:

fatal user trap:

    trap entry = 0x2 (memory management fault)
    a0         = 0xa80f4a10
    a1         = 0x1
    a2         = 0xffffffffffffffff
    pc         = 0xa80f4a10
    ra         = 0x1200f4a1c
    curproc    = 0xfffffe008a74b200
        pid = 15396, comm = cc1


Note that the faulting address && pc is nonsense, so either cc1
jumped off into the wild blue yonder or it's PC got trashed
another way. I'll think some more on this one...

-matt