2018-11-28  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/88223
	* tree-ssa-sccvn.c (vn_reference_lookup_3): When skipping
	over a stored-same value may-alias store make sure to consider
	partial overlaps which are valid when TBAA reasonings do not
	apply and byte-granular overlaps are possible at all.

	* gcc.dg/torture/pr88223.c: New testcase.

From-SVN: r266560