A question about mov pattern

[Peter Bergner]

On Thu, 2010-06-24 at 08:57 -0600, Jeff Law wrote:
> On 06/24/10 02:02, Revital1 Eres wrote:
> > Hello,
> >
> > In the new target I'm working on there are branch regs and gprs.
> > The loads and store instructions are only to/from the gprs, so if a
> > branch reg needs to be spilled it first needs to be moved to a gpr and
> > then stored to memory.  I've implemented mov pattern in the machine
> > description file for the gprs and a mov pattern between gprs and branch
> > regs; however I'm am not sure if I need to add more to model the behavior
> > described above and if so how to do it.
> >    
> Secondary reloads is the answer.
> 
> This isn't a terribly uncommon situation.  Handling of the shift 
> register  (SAR) on the PA would be a good example.  You can move the SAR 
> to/from a GPR, but SAR can not be stored directly to memory.  Searches 
> for SAR in pa.c will get you a long way.

The same is true for the condition register on PowerPC.

Peter