target.def (vector_alignment): New target hook.

target.def (vector_alignment): New target hook.

ChangeLog:

	* target.def (vector_alignment): New target hook.
	* doc/tm.texi.in (TARGET_VECTOR_ALIGNMENT): Document new hook.
	* doc/tm.texi: Regenerate.
	* targhooks.c (default_vector_alignment): New function.
	* targhooks.h (default_vector_alignment): Add prototype.
	* stor-layout.c (layout_type): Use targetm.vector_alignment.
	* config/arm/arm.c (arm_vector_alignment): New function.
	(TARGET_VECTOR_ALIGNMENT): Define.

	* tree-vect-data-refs.c (vect_update_misalignment_for_peel): Use
	vector type alignment instead of size.
	* tree-vect-loop-manip.c (vect_do_peeling_for_loop_bound): Use
	element type size directly instead of computing it from alignment.
	Fix variable naming and comment.

testsuite/ChangeLog:

	* lib/target-supports.exp
	(check_effective_target_vect_natural_alignment): New function.
	* gcc.dg/align-2.c: Only run on targets with natural alignment
	of vector types.
	* gcc.dg/vect/slp-25.c: Adjust tests for targets without natural
	alignment of vector types.

Co-Authored-By: Richard Earnshaw <rearnsha@arm.com>
From-SVN: r189974