PowerPC reusing CTR register for nested loops

[David Edelsohn]

>>>>> Jeffrey A Law writes:

Jeff> Could be that we run loop opts twice now.  That's the only thing that
Jeff> immediately comes to mind.

	Yes, that turns out to be the problem.  Re-running loop_optimize()
clears out the scoreboard of CTR in use.  On the second pass it again
tries to utilize the CTR register on a loop that it discarded on the
previous pass because the regsiter was in use.  Of course with a blank
slate, it succeeds this time.

	I am going to pass in an additional flag to loop_optimize() to
avoid calling the BCT optimization during the "rerun" first time through
and see if things now work.

David