Make early return predictor more precise.

2017-06-21  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/79489
	* gimplify.c (maybe_add_early_return_predict_stmt): New
	function.
	(gimplify_return_expr): Call the function.
	* predict.c (tree_estimate_probability_bb): Remove handling
	of early return.
	* predict.def: Update comment about early return predictor.
	* gimple-predict.h (is_gimple_predict): New function.
	* predict.def: Change default value of early return to 66.
	* tree-tailcall.c (find_tail_calls): Skip GIMPLE_PREDICT
	statements.
	* passes.def: Put pass_strip_predict_hints to the beginning of
	IPA passes.

From-SVN: r249450