PATCH [6/n]: Prepare x32: PR rtl-optimization/47449: Don't propagate hard register non-local goto save area

[Paolo Bonzini]

On 07/05/2011 01:54 AM, Alan Modra wrote:
> >  Before that,  fwprop never tries to work on hard registers.
>
> I question this claim.  It seems to me that fwprop did look at
> paradoxical subregs of hard regs before my change.

That wasn't part of the design anyway.  The main purpose of fwprop's 
paradoxical subreg propagation is to get rid of back-to-back 
SI-to-QI-to-SI conversions, and working with pseudos is enough.

The patch is okay as far as I'm concerned, but I'm not a maintainer of 
fwprop.  Perhaps it could be conditionalized on SMALL_REGISTER_CLASSES 
(that's the source of the bug, I think: the single-register class "D" 
conflicts with an argument register) but I don't think it's worth it.

Paolo