diff --git a/tcg/tcg.c b/tcg/tcg.c
index dfd48b8264..b1a7465df2 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -4927,7 +4927,7 @@ static void tcg_reg_alloc_dup(TCGContext *s, const TCGOp *op)
 
     if (its->val_type == TEMP_VAL_CONST) {
         /* Propagate constant via movi -> dupi.  */
-        tcg_target_ulong val = its->val;
+        tcg_target_ulong val = dup_const(vece, its->val);
         if (IS_DEAD_ARG(1)) {
             temp_dead(s, its);
         }