alpha return address patch

[Richard Henderson]

> I don't think using RETURN_ADDR_RTX should force the return address into
> the stack; the current code should be able to handle having the return
> address in a register just fine.

Except that it is very difficult to handle writing to that value
and having it be seen by the epilogue.

If you can suggest, perhaps, a way to do elimination such that
one way we have a (mem (plus (reg FP) (const ofs))) and the
other a (reg RA), I'd be delighted to use it.


r~