diff --git a/test_regress/t/t_dfg_break_cycles.cpp b/test_regress/t/t_dfg_break_cycles.cpp
index d8bffdbaf..73916afc0 100644
--- a/test_regress/t/t_dfg_break_cycles.cpp
+++ b/test_regress/t/t_dfg_break_cycles.cpp
@@ -24,8 +24,8 @@ int main(int, char**) {
     VerilatedContext ctx;
 
     // Create models
-    Vref ref{&ctx};
-    Vopt opt{&ctx};
+    Vref ref{&ctx, "ref"};
+    Vopt opt{&ctx, "opt"};
 
     uint64_t rand_a = 0x5aef0c8dd70a4497;
     uint64_t rand_b = 0xf0c0a8dd75ae4497;
diff --git a/test_regress/t/t_dfg_peephole.cpp b/test_regress/t/t_dfg_peephole.cpp
index 9508c7d75..26bf7d6d3 100644
--- a/test_regress/t/t_dfg_peephole.cpp
+++ b/test_regress/t/t_dfg_peephole.cpp
@@ -24,8 +24,8 @@ int main(int, char**) {
     VerilatedContext ctx;
 
     // Create models
-    Vref ref{&ctx};
-    Vopt opt{&ctx};
+    Vref ref{&ctx, "ref"};
+    Vopt opt{&ctx, "opt"};
 
     uint64_t rand_a = 0x5aef0c8dd70a4497;
     uint64_t rand_b = 0xf0c0a8dd75ae4497;
diff --git a/test_regress/t/t_dfg_synthesis.cpp b/test_regress/t/t_dfg_synthesis.cpp
index d8bffdbaf..73916afc0 100644
--- a/test_regress/t/t_dfg_synthesis.cpp
+++ b/test_regress/t/t_dfg_synthesis.cpp
@@ -24,8 +24,8 @@ int main(int, char**) {
     VerilatedContext ctx;
 
     // Create models
-    Vref ref{&ctx};
-    Vopt opt{&ctx};
+    Vref ref{&ctx, "ref"};
+    Vopt opt{&ctx, "opt"};
 
     uint64_t rand_a = 0x5aef0c8dd70a4497;
     uint64_t rand_b = 0xf0c0a8dd75ae4497;