* cfg.c (update_bb_profile_for_threading): Use RDIV.
	(scale_bbs_frequencies_int): Likewise, assert for possible overflow.
	(scale_bbs_frequencies_gcov_type): Be more curefull about overflows and
	roundoff errors.
	* tree-cfg.c (tree_duplicate_sese_region): Use counts for updating
	profile when available.
	* update-loopch.c: New testcase.

From-SVN: r102466