* tree-flow.h (loop_only_exit_p): Declare.
	* tree-ssa-loop-niter.c (loop_only_exit_p): Make public.
	* tree-ssa-loop-ivopts.c (may_eliminate_iv): Reinstate direct check on
	the number of iterations if it is constant.  Otherwise, if this is the
	only possible exit of the loop, use the conservative estimate on the
	number of iterations of the entire loop if available.

From-SVN: r137437