[PATCH 2/2] var-tracking: Add entry values up to max register mode

[Stefan Schulze Frielinghaus via Gcc-patches]

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.
---
 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))
-- 
2.37.2