diff --git a/vvp/arith.cc b/vvp/arith.cc
index c67846d9f..b905c46aa 100644
--- a/vvp/arith.cc
+++ b/vvp/arith.cc
@@ -830,7 +830,7 @@ vvp_cmp_gtge_base_::vvp_cmp_gtge_base_(unsigned wid, bool flag)
 
 
 void vvp_cmp_gtge_base_::recv_vec4_base_(vvp_net_ptr_t ptr,
-					 vvp_vector4_t bit,
+					 const vvp_vector4_t&bit,
 					 vvp_bit4_t out_if_equal)
 {
       dispatch_operand_(ptr, bit);
diff --git a/vvp/arith.h b/vvp/arith.h
index 5c6945526..9caed5707 100644
--- a/vvp/arith.h
+++ b/vvp/arith.h
@@ -212,7 +212,7 @@ class vvp_cmp_gtge_base_ : public vvp_arith_ {
       explicit vvp_cmp_gtge_base_(unsigned wid, bool signed_flag);
 
     protected:
-      void recv_vec4_base_(vvp_net_ptr_t ptr, vvp_vector4_t bit,
+      void recv_vec4_base_(vvp_net_ptr_t ptr, const vvp_vector4_t&bit,
 			   vvp_bit4_t out_if_equal);
     private:
       bool signed_flag_;