2017-03-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/80170
	* tree-vect-data-refs.c (vect_compute_data_ref_alignment): Make
	sure DR/SCEV didnt fold in constants we do not see when looking
	at the reference base alignment.

	* gcc.dg/pr80170.c: New testcase.

From-SVN: r246491