BCT optimization

[Jeffrey A Law]

  In message < 9809291910.AA33794@marc.watson.ibm.com >you write:
  > 	Currently the BCT initialization code is quite PowerPC-specific: a
  > GPR and a COUNT_REGISTER_REGNUM register are generated.
Get rid of the magic COUNT_REGISTER_REGNUM stuff.  There's no reason to use a
hard register.  Use a pseudo and let the register allocators and reload DTRT.

It'll probably mean that you'll need to define some secondary reloads to get
data in/out of the count reg, but it's really the right way to go.

jeff