Problem in locate_and_pad_parm

[Richard Kenner]

    Probably because there are only 5 ARGS_GROW_DOWNWARD targets and of
    these only PA is in heavy use? And PA has REG_PARM_STACK_SPACE > 0 so
    it makes no difference there. This code certainly looks like only the
    stuff immediately necessary was added. I don't think we should care
    about this too much.

I do, because it helps us understand the code and what's right or wrong with
it.  An assymmetry like this points out something is wrong.

    Hmm, maybe I should ask the other way round, why is expand_call
    looking at alignment_pad for an arg being partial in a register?

Because store_one_arg is being called in that case.