[gcc r16-5974] cfg: add debug dump to make_forwarders_with_degenerate_phis.

[Andrew Pinski]

https://gcc.gnu.org/g:8e9d923a932e691030d0a0e0adbc0574d5b18350

commit r16-5974-g8e9d923a932e691030d0a0e0adbc0574d5b18350
Author: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
Date:   Sat Dec 6 01:10:07 2025 -0800

    cfg: add debug dump to make_forwarders_with_degenerate_phis.
    
    To understand what this function does, add a debug dump.
    
    Bootstrapped and tested on x86_64-linux-gnu.
    
    gcc/ChangeLog:
    
            * tree-cfg.cc (make_forwarders_with_degenerate_phis): Add debug
            dump.
    
    Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>

Diff:
---
 gcc/tree-cfg.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index 243740e8e219..f0a5e0538b1d 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -10344,6 +10344,13 @@ make_forwarders_with_degenerate_phis (function *fn)
 			  (PHI_ARG_DEF_FROM_EDGE (vphi, args[j].first));
 		    }
 		  free_dominance_info (fn, CDI_DOMINATORS);
+		  if (dump_file && (dump_flags & TDF_DETAILS))
+		    {
+		      fprintf (dump_file, "New forwarder block for edge ");
+		      fprintf (dump_file, "%d -> %d.\n",
+			       args[start].first->src->index,
+			       args[start].first->dest->index);
+		    }
 		  basic_block forwarder = split_edge (args[start].first);
 		  profile_count count = profile_count::zero ();
 		  bool irr = false;