[gcc r14-9687] tree-optimization/114057 - handle BB reduction remain defs as LIVE

[Richard Biener]

https://gcc.gnu.org/g:0b02da5b99e89347f5f8bf875ec8318f84adff18

commit r14-9687-g0b02da5b99e89347f5f8bf875ec8318f84adff18
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Mar 27 11:37:16 2024 +0100

    tree-optimization/114057 - handle BB reduction remain defs as LIVE
    
    The following makes sure to record the scalars we add to the BB
    reduction vectorization result as scalar uses for the purpose of
    computing live lanes.  This restores vectorization in the
    bondfree.c TU of 435.gromacs.
    
            PR tree-optimization/114057
            * tree-vect-slp.cc (vect_bb_slp_mark_live_stmts): Mark
            BB reduction remain defs as scalar uses.

Diff:
---
 gcc/tree-vect-slp.cc | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 23f9593191a..f57684ca685 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -6646,8 +6646,14 @@ vect_bb_slp_mark_live_stmts (bb_vec_info bb_vinfo)
   auto_vec<slp_tree> worklist;
 
   for (slp_instance instance : bb_vinfo->slp_instances)
-    if (!visited.add (SLP_INSTANCE_TREE (instance)))
-      worklist.safe_push (SLP_INSTANCE_TREE (instance));
+    {
+      if (SLP_INSTANCE_KIND (instance) == slp_inst_kind_bb_reduc)
+	for (tree op : SLP_INSTANCE_REMAIN_DEFS (instance))
+	  if (TREE_CODE (op) == SSA_NAME)
+	    scalar_use_map.put (op, 1);
+      if (!visited.add (SLP_INSTANCE_TREE (instance)))
+	worklist.safe_push (SLP_INSTANCE_TREE (instance));
+    }
 
   do
     {
@@ -6665,7 +6671,8 @@ vect_bb_slp_mark_live_stmts (bb_vec_info bb_vinfo)
 	    if (child && !visited.add (child))
 	      worklist.safe_push (child);
 	}
-    } while (!worklist.is_empty ());
+    }
+  while (!worklist.is_empty ());
 
   visited.empty ();