[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

1 files changed, 19 insertions, 6 deletions

diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c
index 30dcc44..8e02647 100644
--- a/gcc/tree-vectorizer.c
+++ b/gcc/tree-vectorizer.c
@@ -874,6 +874,7 @@ try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
   vec_info_shared shared;
   auto_purge_vect_location sentinel;
   vect_location = find_loop_location (loop);
+
   if (LOCATION_LOCUS (vect_location.get_location_t ()) != UNKNOWN_LOCATION
       && dump_enabled_p ())
     dump_printf (MSG_NOTE | MSG_PRIORITY_INTERNALS,
@@ -881,10 +882,17 @@ try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
 		 LOCATION_FILE (vect_location.get_location_t ()),
 		 LOCATION_LINE (vect_location.get_location_t ()));
 
-  /* Try to analyze the loop, retaining an opt_problem if dump_enabled_p.  */
-  opt_loop_vec_info loop_vinfo
-    = vect_analyze_loop (loop, orig_loop_vinfo, &shared);
-  loop->aux = loop_vinfo;
+  opt_loop_vec_info loop_vinfo = opt_loop_vec_info::success (NULL);
+  /* In the case of epilogue vectorization the loop already has its
+     loop_vec_info set, we do not require to analyze the loop in this case.  */
+  if (loop_vec_info vinfo = loop_vec_info_for_loop (loop))
+    loop_vinfo = opt_loop_vec_info::success (vinfo);
+  else
+    {
+      /* Try to analyze the loop, retaining an opt_problem if dump_enabled_p.  */
+      loop_vinfo = vect_analyze_loop (loop, orig_loop_vinfo, &shared);
+      loop->aux = loop_vinfo;
+    }
 
   if (!loop_vinfo)
     if (dump_enabled_p ())
@@ -1012,8 +1020,13 @@ try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
 
   /* Epilogue of vectorized loop must be vectorized too.  */
   if (new_loop)
-    ret |= try_vectorize_loop_1 (simduid_to_vf_htab, num_vectorized_loops,
-				 new_loop, loop_vinfo, NULL, NULL);
+    {
+      /* Don't include vectorized epilogues in the "vectorized loops" count.
+       */
+      unsigned dont_count = *num_vectorized_loops;
+      ret |= try_vectorize_loop_1 (simduid_to_vf_htab, &dont_count,
+				   new_loop, loop_vinfo, NULL, NULL);
+    }
 
   return ret;
 }