condition codes, haifa-sched and virtual-stack-vars

[Ulrich Weigand]

Following up on myself:

> The reload_inhi pattern tries to allocate the carry register as the
> secondary reload scratch register.  Now, in the interesting case 
> where the carry register is in fact live at the location where the
> insn is inserted, this would mean that reload would need to spill
> the carry register and later on restore its old value, right?
> (Because there is only a single register in this class ...)
> 
> However, I'm not sure how the carry register can be spilled,
> given that there is no mov* insn that touches it, unless I'm
> missing something ...

Hmm, what I was missing was that apparently the carry register
can *never* be live during reload, as all insns that actually
use it (except for just a clobber) are *only* ever emitted from 
splitters after reload.

So what I called the 'interesting case' above never happens ...


Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  weigand@informatik.uni-erlangen.de