[vect]PR 88915: Vectorize epilogues when versioning loops

[vect]PR 88915: Vectorize epilogues when versioning loops

gcc/ChangeLog:
2019-10-29  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	PR 88915
	* tree-ssa-loop-niter.h (simplify_replace_tree): Change declaration.
	* tree-ssa-loop-niter.c (simplify_replace_tree): Add context parameter
	and make the valueize function pointer also take a void pointer.
	* gcc/tree-ssa-sccvn.c (vn_valueize_wrapper): New function to wrap
	around vn_valueize, to call it without a context.
	(process_bb): Use vn_valueize_wrapper instead of vn_valueize.
	* tree-vect-loop.c (_loop_vec_info): Initialize epilogue_vinfos.
	(~_loop_vec_info): Release epilogue_vinfos.
	(vect_analyze_loop_costing): Use knowledge of main VF to estimate
	number of iterations of epilogue.
	(vect_analyze_loop_2): Adapt to analyse main loop for all supported
	vector sizes when vect-epilogues-nomask=1.  Also keep track of lowest
	versioning threshold needed for main loop.
	(vect_analyze_loop): Likewise.
	(find_in_mapping): New helper function.
	(update_epilogue_loop_vinfo): New function.
	(vect_transform_loop): When vectorizing epilogues re-use analysis done
	on main loop and call update_epilogue_loop_vinfo to update it.
	* tree-vect-loop-manip.c (vect_update_inits_of_drs): No longer insert
	stmts on loop preheader edge.
	(vect_do_peeling): Enable skip-vectors when doing loop versioning if
	we decided to vectorize epilogues.  Update epilogues NITERS and
	construct ADVANCE to update epilogues data references where needed.
	* tree-vectorizer.h (_loop_vec_info): Add epilogue_vinfos.
	(vect_do_peeling, vect_update_inits_of_drs,
	 determine_peel_for_niter, vect_analyze_loop): Add or update
	declarations.
	* tree-vectorizer.c (try_vectorize_loop_1): Make sure to use already
	created loop_vec_info's for epilogues when available.  Otherwise analyse
	epilogue separately.

From-SVN: r277569