[gcc r12-3875] Fix value uninitialization in vn_reference_insert_pieces [PR102400]

[Feng Xue]

https://gcc.gnu.org/g:29c92857039d0a105281be61c10c9e851aaeea4a

commit r12-3875-g29c92857039d0a105281be61c10c9e851aaeea4a
Author: Feng Xue <fxue@os.amperecomputing.com>
Date:   Thu Sep 23 09:14:33 2021 +0800

    Fix value uninitialization in vn_reference_insert_pieces [PR102400]
    
    2021-09-23  Feng Xue  <fxue@os.amperecomputing.com>
    
    gcc/
            PR tree-optimization/102400
            * tree-ssa-sccvn.c (vn_reference_insert_pieces): Initialize
            result_vdef to zero value.

Diff:
---
 gcc/tree-ssa-sccvn.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index a901f51a025..e8b1c39184d 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -3811,6 +3811,7 @@ vn_reference_insert_pieces (tree vuse, alias_set_type set,
   if (result && TREE_CODE (result) == SSA_NAME)
     result = SSA_VAL (result);
   vr1->result = result;
+  vr1->result_vdef = NULL_TREE;
 
   slot = valid_info->references->find_slot_with_hash (vr1, vr1->hashcode,
 						      INSERT);