[gcc(refs/users/marxin/heads/slp-ebb-v2)] Handle non-empty basic blocks.

[gcc(refs/users/marxin/heads/slp-ebb-v2)] Handle non-empty basic blocks.

[Martin Liska]

https://gcc.gnu.org/g:802fefb4dbab5c558e4ab671e6f0a9b29e7875bb

commit 802fefb4dbab5c558e4ab671e6f0a9b29e7875bb
Author: Martin Liska <mliska@suse.cz>
Date:   Thu Sep 24 15:15:00 2020 +0200

    Handle non-empty basic blocks.

Diff:
---
 gcc/tree-vect-slp.c   | 35 +++++++++++++++++++++--------------
 gcc/tree-vectorizer.c |  6 +++---
 gcc/tree-vectorizer.h | 25 +++++++++++++++----------
 3 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 2cea4cf89fa..9cd76a46ff3 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -2729,10 +2729,10 @@ vect_detect_hybrid_slp (loop_vec_info loop_vinfo)
 
 /* Initialize a bb_vec_info struct for the statements in BBS basic blocks.  */
 
-_bb_vec_info::_bb_vec_info (vec<basic_block> _bbs,
-			    vec_info_shared *shared)
+_bb_vec_info::_bb_vec_info (vec<basic_block> _bbs, vec<basic_block>
+			    _nonempty_bbs, vec_info_shared *shared)
   : vec_info (vec_info::bb, init_cost (NULL), shared),
-  bbs (_bbs)
+  bbs (_bbs), nonempty_bbs (_nonempty_bbs)
 {
   for (gimple *stmt : this->region_stmts ())
     {
@@ -3598,7 +3598,7 @@ vect_slp_analyze_bb_1 (bb_vec_info bb_vinfo, int n_stmts, bool &fatal,
    The region has N_STMTS statements and has the datarefs given by DATAREFS.  */
 
 static bool
-vect_slp_region (vec<basic_block> bbs,
+vect_slp_region (vec<basic_block> bbs, vec<basic_block> nonempty_bbs,
 		 vec<data_reference_p> datarefs,
 		 vec<int> *dataref_groups,
 		 unsigned int n_stmts)
@@ -3618,7 +3618,7 @@ vect_slp_region (vec<basic_block> bbs,
     {
       bool vectorized = false;
       bool fatal = false;
-      bb_vinfo = new _bb_vec_info (bbs, &shared);
+      bb_vinfo = new _bb_vec_info (bbs, nonempty_bbs, &shared);
 
       bool first_time_p = shared.datarefs.is_empty ();
       BB_VINFO_DATAREFS (bb_vinfo) = datarefs;
@@ -3751,6 +3751,18 @@ vect_slp_bbs (vec<basic_block> bbs)
   vec<int> dataref_groups = vNULL;
   int insns = 0;
   int current_group = 0;
+  auto_vec<basic_block> nonempty_bbs;
+
+  for (unsigned i = 0; i < bbs.length (); i++)
+    {
+      basic_block bb = bbs[i];
+      gimple_stmt_iterator gsi = gsi_start_nondebug_after_labels_bb (bb);
+      if (!gsi_end_p (gsi))
+	nonempty_bbs.safe_push (bb);
+    }
+
+  if (nonempty_bbs.is_empty ())
+    return false;
 
   for (unsigned i = 0; i < bbs.length (); i++)
     {
@@ -3781,7 +3793,7 @@ vect_slp_bbs (vec<basic_block> bbs)
 	}
     }
 
-  return vect_slp_region (bbs, datarefs, &dataref_groups, insns);
+  return vect_slp_region (bbs, nonempty_bbs, datarefs, &dataref_groups, insns);
 }
 
 /* Main entry for the BB vectorizer.  Analyze and transform BB, returns
@@ -3811,18 +3823,13 @@ vect_slp_function ()
     {
       basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]);
       gphi_iterator phi = gsi_start_phis (bb);
-      gimple_stmt_iterator gsi = gsi_start_nondebug_after_labels_bb (bb);
       if (gsi_end_p (phi))
-	{
-	  if (!gsi_end_p (gsi))
-	    ebb.safe_push (bb);
-	}
+	ebb.safe_push (bb);
       else if (!ebb.is_empty ())
 	{
 	  r |= vect_slp_bbs (ebb);
 	  ebb.truncate (0);
-	  if (!gsi_end_p (gsi))
-	    ebb.quick_push (bb);
+	  ebb.quick_push (bb);
 	}
     }
 
@@ -4709,7 +4716,7 @@ vect_schedule_slp_instance (vec_info *vinfo,
 	       we do not insert before the region boundary.  */
 	    if (SLP_TREE_SCALAR_OPS (child).is_empty ()
 		&& !vinfo->lookup_def (SLP_TREE_VEC_DEFS (child)[0]))
-	      last_stmt = gsi_stmt (as_a <bb_vec_info> (vinfo)->region_begin ());
+	      last_stmt = gsi_stmt (as_a <bb_vec_info> (vinfo)->region_begin (false));
 	    else
 	      {
 		unsigned j;
diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c
index 658bd19bbc9..e218bdcab58 100644
--- a/gcc/tree-vectorizer.c
+++ b/gcc/tree-vectorizer.c
@@ -607,8 +607,8 @@ vec_info::remove_stmt (stmt_vec_info stmt_info)
   gimple_stmt_iterator si = gsi_for_stmt (stmt_info->stmt);
   gimple_stmt_iterator psi = si;
   if (bb_vec_info bb_vinfo = dyn_cast <bb_vec_info> (this))
-    if (gsi_stmt (bb_vinfo->region_begin ()) == stmt_info->stmt)
-      psi = bb_vinfo->region_begin ();
+    if (gsi_stmt (bb_vinfo->region_begin (false)) == stmt_info->stmt)
+      psi = bb_vinfo->region_begin (false);
   gsi_remove (&psi, true);
   release_defs (stmt_info->stmt);
   free_stmt_vec_info (stmt_info);
@@ -653,7 +653,7 @@ vec_info::insert_seq_on_entry (stmt_vec_info context, gimple_seq seq)
   else
     {
       bb_vec_info bb_vinfo = as_a <bb_vec_info> (this);
-      gimple_stmt_iterator gsi_region_begin = bb_vinfo->region_begin ();
+      gimple_stmt_iterator gsi_region_begin = bb_vinfo->region_begin (false);
       gsi_insert_seq_before (&gsi_region_begin, seq, GSI_SAME_STMT);
     }
 }
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 9c54bab2916..49d7470c296 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -905,19 +905,22 @@ public:
     int bb_index;
   };
 
-  _bb_vec_info (vec<basic_block> bbs, vec_info_shared *);
+  _bb_vec_info (vec<basic_block> bbs, vec<basic_block> nonempty_bbs,
+		vec_info_shared *);
   ~_bb_vec_info ();
 
   // TODO
-  gimple_stmt_iterator region_begin ()
+  gimple_stmt_iterator region_begin (bool non_empty_bb)
   {
-    return gsi_start_nondebug_after_labels_bb (bbs[0]);
+    vec<basic_block> &v = non_empty_bb ? nonempty_bbs : bbs;
+    return gsi_start_nondebug_after_labels_bb (v[0]);
   }
 
   // TODO
-  gimple_stmt_iterator region_end ()
+  gimple_stmt_iterator region_end (bool non_empty_bb)
   {
-    gimple_stmt_iterator gsi = gsi_last_bb (bbs[bbs.length () - 1]);
+    vec<basic_block> &v = non_empty_bb ? nonempty_bbs : bbs;
+    gimple_stmt_iterator gsi = gsi_last_bb (v[v.length () - 1]);
     if (!gsi_end_p (gsi))
       gsi_next (&gsi);
     return gsi;
@@ -928,8 +931,8 @@ public:
   iterator_range<const_iterator>
   region_stmts ()
   {
-    return iterator_range<const_iterator> (const_iterator (region_begin (), bbs),
-					   const_iterator (region_end (), bbs));
+    return iterator_range<const_iterator> (const_iterator (region_begin (true), nonempty_bbs),
+					   const_iterator (region_end (true), nonempty_bbs));
   }
 
   /* Returns iterator_range for range-based loop in a reverse order.  */
@@ -937,17 +940,19 @@ public:
   iterator_range<const_reverse_iterator>
   reverse_region_stmts ()
   {
-    const_reverse_iterator begin (region_end (), bbs);
+    const_reverse_iterator begin (region_end (true), nonempty_bbs);
     if (*begin == NULL)
-      begin = const_reverse_iterator (gsi_last_bb (gsi_bb (region_end ())), bbs);
+      begin = const_reverse_iterator (gsi_last_bb (gsi_bb (region_end (true))),
+				      nonempty_bbs);
     else
       ++begin;
 
-    const_reverse_iterator end (region_begin (), bbs);
+    const_reverse_iterator end (region_begin (true), nonempty_bbs);
     return iterator_range<const_reverse_iterator> (begin, ++end);
   }
 
   vec<basic_block> bbs;
+  vec<basic_block> nonempty_bbs;
 } *bb_vec_info;
 
 #define BB_VINFO_BB(B)               (B)->bb