[gcc r17-2826] Dump SLP subgraph entries upon costing

https://gcc.gnu.org/g:d458a4daa68cdbaa869344ec1a75360a842ef19e

commit r17-2826-gd458a4daa68cdbaa869344ec1a75360a842ef19e
Author: Richard Biener <[email protected]>
Date:   Thu Jul 30 14:42:25 2026 +0200

    Dump SLP subgraph entries upon costing
    
    I found this useful information.
    
            * tree-vect-slp.cc (vect_bb_vectorization_profitable_p):
            Dump SLP graph entries.

Diff:
---
 gcc/tree-vect-slp.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 510e8daeec66..b4eb9c204cbb 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -9652,7 +9652,11 @@ vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo,
 
   if (dump_enabled_p ())
     {
-      dump_printf_loc (MSG_NOTE, vect_location, "Costing subgraph: \n");
+      dump_printf_loc (MSG_NOTE, vect_location, "Costing subgraph:\n");
+      FOR_EACH_VEC_ELT (slp_instances, i, instance)
+	dump_printf_loc (MSG_NOTE, vect_location, "   entry instance %p -> "
+			 "node %p\n", (void *)instance,
+			 (void *)SLP_INSTANCE_TREE (instance));
       hash_set<slp_tree> visited;
       FOR_EACH_VEC_ELT (slp_instances, i, instance)
 	vect_print_slp_graph (MSG_NOTE, vect_location,