Vector peeling cost model 6/6

gcc/ChangeLog:

2017-05-24  Robin Dapp  <rdapp@linux.vnet.ibm.com>

	* tree-vect-data-refs.c (vect_get_peeling_costs_all_drs):
	Introduce unknown_misalignment parameter and remove vf.
	(vect_peeling_hash_get_lowest_cost):
	Pass unknown_misalignment parameter.
	(vect_enhance_data_refs_alignment):
	Fix unsupportable data ref treatment.

From-SVN: r248680