[vect] PR 92351: When peeling for alignment make alignment of epilogues unknown

[vect] PR 92351: When peeling for alignment make alignment of epilogues unknown

gcc/ChangeLog:
2019-11-08  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	PR tree-optimization/92351
	* tree-vect-data-refs.c (vect_compute_data_ref_alignment): When we are
	peeling the main loop for alignment, make sure to set the misalignment
	of the epilogue's data references to DR_MISALIGNMENT_UNKNOWN.

gcc/testsuite/ChangeLog:
2019-11-08  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	PR tree-optimization/92351
	* gcc.dg/vect/vect-peel-2.c: Disable epilogue vectorization and
	split the source of this test to...
	* gcc.dg/vect/vect-peel-2-src.c: ... This.
	* gcc.dg/vect/vect-peel-2-epilogues.c: New test.

From-SVN: r277974