[gcc r13-2917] var-tracking: Add entry values up to max register mode

[Stefan Schulze Frielinghaus <stefansf@gcc.gnu.org>]

https://gcc.gnu.org/g:5d7be27bf7ef63c770a591f69845c4245522cd76

commit r13-2917-g5d7be27bf7ef63c770a591f69845c4245522cd76
Author: Stefan Schulze Frielinghaus <stefansf@linux.ibm.com>
Date:   Wed Sep 28 17:27:11 2022 +0200

    var-tracking: Add entry values up to max register mode
    
    For parameter of type integer which do not consume a whole register
    (modulo sign/zero extension) this patch adds entry values up to maximal
    register mode.
    
    gcc/ChangeLog:
    
            * var-tracking.cc (vt_add_function_parameter): Add entry values
            up to maximal register mode.

Diff:
---
 gcc/var-tracking.cc | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/gcc/var-tracking.cc b/gcc/var-tracking.cc
index 235981d100f..9c40ec4fb8b 100644
--- a/gcc/var-tracking.cc
+++ b/gcc/var-tracking.cc
@@ -9906,6 +9906,23 @@ vt_add_function_parameter (tree parm)
 				     VAR_INIT_STATUS_INITIALIZED, NULL, INSERT);
 		}
 	    }
+
+	  if (GET_MODE_CLASS (mode) == MODE_INT)
+	    {
+	      machine_mode wider_mode_iter;
+	      FOR_EACH_WIDER_MODE (wider_mode_iter, mode)
+		{
+		  if (!HWI_COMPUTABLE_MODE_P (wider_mode_iter))
+		    break;
+		  rtx wider_reg
+		    = gen_rtx_REG (wider_mode_iter, REGNO (incoming));
+		  cselib_val *wider_val
+		    = cselib_lookup_from_insn (wider_reg, wider_mode_iter, 1,
+					       VOIDmode, get_insns ());
+		  preserve_value (wider_val);
+		  record_entry_value (wider_val, wider_reg);
+		}
+	    }
 	}
     }
   else if (GET_CODE (incoming) == PARALLEL && !dv_onepart_p (dv))