remove premature vect_verify_datarefs_alignment

remove premature vect_verify_datarefs_alignment

This followup removes vect_verify_datarefs_alignment and its
premature cancellation of vectorization leaving the actual
decision whether alignment is supported to the functions
deciding whether we can vectorize a load or store.

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

	* tree-vectorizer.h (vect_verify_datarefs_alignment): Remove.
	(vect_slp_analyze_and_verify_instance_alignment): Rename to ...
	(vect_slp_analyze_instance_alignment): ... this.
	* tree-vect-data-refs.c (verify_data_ref_alignment): Remove.
	(vect_verify_datarefs_alignment): Likewise.
	(vect_enhance_data_refs_alignment): Do not call
	vect_verify_datarefs_alignment.
	(vect_slp_analyze_node_alignment): Rename from
	vect_slp_analyze_and_verify_node_alignment and do not
	call verify_data_ref_alignment.
	(vect_slp_analyze_instance_alignment): Rename from
	vect_slp_analyze_and_verify_instance_alignment.
	* tree-vect-stmts.c (vectorizable_store): Dump when
	we vectorize an unaligned access.
	(vectorizable_load): Likewise.
	* tree-vect-loop.c (vect_analyze_loop_2): Do not call
	vect_verify_datarefs_alignment.
	* tree-vect-slp.c (vect_slp_analyze_bb_1): Adjust.

	* gcc.dg/vect/bb-slp-10.c: Adjust.
	* gcc.dg/vect/slp-45.c: Likewise.
	* gcc.dg/vect/vect-109.c: Likewise.