* tree-ssa-loop-niter.c (record_estimate): Add "upper" argument.
	Update constant estimates of number of iterations.
	(record_nonwrapping_iv): Add "upper" argument.  "data_size_bounds_p"
	argument renamed to "realistic".
	(compute_estimated_nb_iterations): Removed.
	(record_niter_bound): New function.
	(idx_infer_loop_bounds): For possible but unlikely tail arrays,
	call record_nonwrapping_iv with upper = false.
	(infer_loop_bounds_from_signedness): Pass upper argument to
	record_nonwrapping_iv.
	(estimate_numbers_of_iterations_loop): Do not call
	compute_estimated_nb_iterations.  Record estimate based on profile
	information.  Initialize the constant estimates of number of
	iterations.
	* tree-data-ref.c (estimated_loop_iterations): Return the recorded
	estimates.
	* tree-ssa-loop-prefetch.c (loop_prefetch_arrays): Add dump when
	number of iterations is too small.
	* cfgloop.h (struct nb_iter_bound): Remove "realistic" field.
	(EST_NOT_AVAILABLE): Removed.
	(struct loop): Replace estimated_nb_iterations by any_upper_bound,
	nb_iterations_upper_bound, any_estimate and nb_iterations_estimate
	fields.

	* gcc.dg/tree-ssa/prefetch-5.c: New test.

From-SVN: r122969