A plan for eliminating cc0

[Ian Lance Taylor]

Richard Henderson <rth@redhat.com> writes:

> Note that there's no longer any insn that *sets* cc_reg.  I think
> that's a bit dangerous.

Hmmm, good point.

> One solution to this is to convert the new setter to 
> 
> 	[(set (reg 1) (plus (reg 1) (reg 2)))
> 	 (set (reg cc_reg) (unspec [(const_int 0)] cc_set))]
> 
> I don't think it matters what we set cc_reg to, just that *some*
> set is visible in the instruction stream.
> 
> This requires that we generate two patterns for clobbercc insns,
> but that shouldn't be a problem.

Makes sense.

Ian