Remove STMT_VINFO_SAME_ALIGN_REFS

Remove STMT_VINFO_SAME_ALIGN_REFS

This makes the only consumer of STMT_VINFO_SAME_ALIGN_REFS, the
loop peeling for alignment code, use locally computed data and
then removes STMT_VINFO_SAME_ALIGN_REFS and its computation.

It also adjusts the auto_vec<> move CTOR/assignment so you
can write

  auto_vec<..> foo = bar.copy ();

and have foo own the generated copy.

2020-10-13  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/97382
	* tree-vectorizer.h (_stmt_vec_info::same_align_refs): Remove.
	(STMT_VINFO_SAME_ALIGN_REFS): Likewise.
	* tree-vectorizer.c (vec_info::new_stmt_vec_info): Do not
	allocate STMT_VINFO_SAME_ALIGN_REFS.
	(vec_info::free_stmt_vec_info): Do not release
	STMT_VINFO_SAME_ALIGN_REFS.
	* tree-vect-data-refs.c (vect_analyze_data_ref_dependences):
	Do not compute self and read-read dependences.
	(vect_dr_aligned_if_related_peeled_dr_is): New helper.
	(vect_dr_aligned_if_peeled_dr_is): Likewise.
	(vect_update_misalignment_for_peel): Use it instead of
	iterating over STMT_VINFO_SAME_ALIGN_REFS.
	(dr_align_group_sort_cmp): New function.
	(vect_enhance_data_refs_alignment): Count the number of
	same aligned refs here and elide uses of STMT_VINFO_SAME_ALIGN_REFS.
	(vect_find_same_alignment_drs): Remove.
	(vect_analyze_data_refs_alignment): Do not call it.
	* vec.h (auto_vec<T, 0>::auto_vec): Adjust CTOR to take
	a vec<>&&, assert it isn't using auto storage.
	(auto_vec& operator=): Apply a similar change.

	* gcc.dg/vect/no-vfa-vect-dv-2.c: Remove same align dump
	scanning.
	* gcc.dg/vect/vect-103.c: Likewise.
	* gcc.dg/vect/vect-91.c: Likewise.
	* gfortran.dg/vect/vect-4.f90: Likewise.