compute and check alignment info during analysis

compute and check alignment info during analysis

This moves querying the alignment support scheme from load/store
transform time to get_load_store_type where we should know best
what alignment constraints we actually need.  This should make
verify_data_ref_alignment obsolete which prematurely disqualifies
all vectorization IMHO.

2020-07-08  Richard Biener  <rguenther@suse.de>

	* tree-vect-stmts.c (get_group_load_store_type): Pass
	in the SLP node and the alignment support scheme output.
	Set that.
	(get_load_store_type): Likewise.
	(vectorizable_store): Adjust.
	(vectorizable_load): Likewise.