2019-01-18  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/88903
	* tree-vect-stmts.c (vectorizable_shift): Verify we see all
	scalar stmts a SLP shift amount is composed of when detecting
	shifts by scalars.

	* gcc.dg/vect/pr88903-1.c: New testcase.
	* gcc.dg/vect/pr88903-2.c: Likewise.

From-SVN: r268076