Fix SLP vectorization of stores from boolean vectors

Fix SLP vectorization of stores from boolean vectors

The following fixes SLP vectorization of stores that were
pattern recognized.  Since in SLP vectorization pattern analysis
happens after dataref group analysis we have to adjust the groups
with the pattern stmts.  This has some effects down the pipeline
and exposes cases where we looked at the wrong pattern/non-pattern
stmts.

2020-11-05  Richard Biener  <rguenther@suse.de>

	* tree-vect-data-refs.c (vect_slp_analyze_node_dependences):
	Use the original stmts.
	(vect_slp_analyze_node_alignment): Use the pattern stmt.
	* tree-vect-slp.c (vect_fixup_store_groups_with_patterns):
	New function.
	(vect_slp_analyze_bb_1): Call it.

	* gcc.dg/vect/bb-slp-69.c: New testcase.