2019-05-06  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/90328
	* tree-data-ref.h (dr_may_alias_p): Pass in the actual loop nest.
	* tree-data-ref.c (dr_may_alias_p): Check whether the clique
	is valid in the loop nest before using it.
	(initialize_data_dependence_relation): Adjust.
	* graphite-scop-detection.c (build_alias_set): Pass the SCOP enclosing
	loop as loop-nest to dr_may_alias_p.

	* gcc.dg/torture/pr90328.c: New testcase.

From-SVN: r270906