I shoulda done this a *long* time ago (tm): implement calls properly,

i.e. r1/r12/rp are saved/restored regardless of scheduling/luck

TODO: calls to external symbols, indirect (function descriptor) calls,
      performance (we're being paranoid right now)

BUG: the code for handling calls to vararg functions breaks if FP
args are passed (this will make printf() go haywire so a bunch of
tests will fail)

BUG: this seems to trigger some legalize nastiness
llvm-svn: 24942