PowerPC reusing CTR register for nested loops

[David Edelsohn]

	Only trying to insert the loop instructions using the CTR register
during *one* of the loop optimization passes works *much* better :^).

	Do you have a feel for whether the BCT instruction should be
attempted on the first call to loop_optimize() or the second one when it
is called twice?  Currently I am trying to insert the instruction only on
the second call to loop_optimize() which does not depend on
rerun_loop_opt.  Would it be better to try to inserting BCT during the
first call to loop_optimize() *if* rerun_loop_opt is enabled and during
the second unconditional call to loop_optimize() only if the first one is
skipped?

Thanks, David