Arg pointer and SSE code

[Jan Hubicka]

Hi
I am looking trought the patches and it looks like handling of arg pointer is quite broken.
Enabling -msse makes gcc to always use register 4 for arg pointer (if I am not mistaken)
independently whether TImodes are used or not.

This can be IMO avoided by always keeping arg pointer eliminable and eliminate it in reload
eighter to STACK/FRAME or HARD_ARG_POINTER.
Question remains, how to determine if we need the alignment code.  It seems to me, that this
needs to be done before reload, most likely by checking functin alignment and going trought
all live pseudos and determining if some of them is TImode.
This is quite overconservative - do you have any better idea?

Honza