diff --git a/test_regress/t/t_clk_inp_init.cpp b/test_regress/t/t_clk_inp_init.cpp
index 6afcc98ce..f6f91d8d6 100644
--- a/test_regress/t/t_clk_inp_init.cpp
+++ b/test_regress/t/t_clk_inp_init.cpp
@@ -2,11 +2,7 @@
 // any use, without warranty, 2020 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
-// Test defines
-// Generated header
-#include "Vt_clk_inp_init.h"
-// General headers
-#include "verilated.h"
+#include VM_PREFIX_INCLUDE
 
 void oneTest(int argc, char** argv, int seed) {
     uint64_t sim_time = 1000;
diff --git a/test_regress/t/t_const_bitoptree_bug3096.cpp b/test_regress/t/t_const_bitoptree_bug3096.cpp
index 8c3dc8625..e8fec7a42 100644
--- a/test_regress/t/t_const_bitoptree_bug3096.cpp
+++ b/test_regress/t/t_const_bitoptree_bug3096.cpp
@@ -9,7 +9,7 @@
 //
 //*************************************************************************
 
-#include <Vt_const_bitoptree_bug3096.h>
+#include VM_PREFIX_INCLUDE
 #include <cassert>
 #include <iostream>
 
diff --git a/test_regress/t/t_dpi_vams.cpp b/test_regress/t/t_dpi_vams.cpp
index 3eed4f0ed..33fac09c8 100644
--- a/test_regress/t/t_dpi_vams.cpp
+++ b/test_regress/t/t_dpi_vams.cpp
@@ -8,7 +8,7 @@
 
 #include <verilated.h>
 
-#include "Vt_dpi_vams.h"
+#include VM_PREFIX_INCLUDE
 
 //======================================================================
 
diff --git a/test_regress/t/t_flag_fi.cpp b/test_regress/t/t_flag_fi.cpp
index e510f4cee..8ff1ba655 100644
--- a/test_regress/t/t_flag_fi.cpp
+++ b/test_regress/t/t_flag_fi.cpp
@@ -8,7 +8,7 @@
 
 #include <verilated.h>
 
-#include "Vt_flag_fi.h"
+#include VM_PREFIX_INCLUDE
 
 //======================================================================
 
diff --git a/test_regress/t/t_func_rand.cpp b/test_regress/t/t_func_rand.cpp
index 772dd9fee..c11d28602 100644
--- a/test_regress/t/t_func_rand.cpp
+++ b/test_regress/t/t_func_rand.cpp
@@ -8,7 +8,7 @@
 
 #include <verilated.h>
 
-#include "Vt_func_rand.h"
+#include VM_PREFIX_INCLUDE
 
 double sc_time_stamp() { return 0; }
 
diff --git a/test_regress/t/t_gantt_two.cpp b/test_regress/t/t_gantt_two.cpp
index 9bea82889..50a30b88b 100644
--- a/test_regress/t/t_gantt_two.cpp
+++ b/test_regress/t/t_gantt_two.cpp
@@ -8,7 +8,7 @@
 
 #include "verilated.h"
 
-#include "Vt_gantt_two.h"
+#include VM_PREFIX_INCLUDE
 
 #include <memory>
 
diff --git a/test_regress/t/t_math_imm2.cpp b/test_regress/t/t_math_imm2.cpp
index 3b2183cba..37cafbf37 100644
--- a/test_regress/t/t_math_imm2.cpp
+++ b/test_regress/t/t_math_imm2.cpp
@@ -5,7 +5,7 @@
 
 #include <verilated.h>
 
-#include "Vt_math_imm2.h"
+#include VM_PREFIX_INCLUDE
 
 double sc_time_stamp() { return 0; }
 
diff --git a/test_regress/t/t_mem_slot.cpp b/test_regress/t/t_mem_slot.cpp
index dfaee4052..595c2768b 100644
--- a/test_regress/t/t_mem_slot.cpp
+++ b/test_regress/t/t_mem_slot.cpp
@@ -5,7 +5,7 @@
 
 #include <verilated.h>
 
-#include "Vt_mem_slot.h"
+#include VM_PREFIX_INCLUDE
 
 #include <cstdlib>
 
diff --git a/test_regress/t/t_multitop_sig.cpp b/test_regress/t/t_multitop_sig.cpp
index b9bb8cfb0..95cc0aa7c 100644
--- a/test_regress/t/t_multitop_sig.cpp
+++ b/test_regress/t/t_multitop_sig.cpp
@@ -8,7 +8,7 @@
 
 #include <verilated.h>
 
-#include "Vt_multitop_sig.h"
+#include VM_PREFIX_INCLUDE
 
 #include <iostream>
 
diff --git a/test_regress/t/t_order_multidriven.cpp b/test_regress/t/t_order_multidriven.cpp
index d8cd782a6..284330498 100644
--- a/test_regress/t/t_order_multidriven.cpp
+++ b/test_regress/t/t_order_multidriven.cpp
@@ -7,7 +7,7 @@
 #include "verilated.h"
 #include "verilated_vcd_c.h"
 
-#include "Vt_order_multidriven.h"
+#include VM_PREFIX_INCLUDE
 
 double sc_time_stamp() { return 0; }
 
diff --git a/test_regress/t/t_order_quad.cpp b/test_regress/t/t_order_quad.cpp
index cf6c247f3..e15584148 100644
--- a/test_regress/t/t_order_quad.cpp
+++ b/test_regress/t/t_order_quad.cpp
@@ -8,7 +8,7 @@
 
 #include <verilated.h>
 
-#include "Vt_order_quad.h"
+#include VM_PREFIX_INCLUDE
 
 //======================================================================
 
diff --git a/test_regress/t/t_sc_names.cpp b/test_regress/t/t_sc_names.cpp
index 4380c8064..354d27ce2 100644
--- a/test_regress/t/t_sc_names.cpp
+++ b/test_regress/t/t_sc_names.cpp
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: CC0-1.0
 
 #include VM_PREFIX_INCLUDE
-#include "Vt_sc_names.h"
 
 using namespace sc_core;
 
diff --git a/test_regress/t/t_scope_map.cpp b/test_regress/t/t_scope_map.cpp
index 9d1e4a39e..93de549dc 100644
--- a/test_regress/t/t_scope_map.cpp
+++ b/test_regress/t/t_scope_map.cpp
@@ -10,7 +10,7 @@
 #include <verilated_syms.h>
 #include <verilated_vcd_c.h>
 
-#include "Vt_scope_map.h"
+#include VM_PREFIX_INCLUDE
 
 #include <map>
 #include <string>
diff --git a/test_regress/t/t_timescale_parse.cpp b/test_regress/t/t_timescale_parse.cpp
index 0b4da3371..2a011930d 100644
--- a/test_regress/t/t_timescale_parse.cpp
+++ b/test_regress/t/t_timescale_parse.cpp
@@ -4,7 +4,7 @@
 // any use, without warranty, 2019 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
-#include "Vt_timescale_parse.h"
+#include VM_PREFIX_INCLUDE
 
 VM_PREFIX* tb = nullptr;
 
diff --git a/test_regress/t/t_trace_noflag_bad_c.cpp b/test_regress/t/t_trace_noflag_bad_c.cpp
index 1fccdddd3..d46885332 100644
--- a/test_regress/t/t_trace_noflag_bad_c.cpp
+++ b/test_regress/t/t_trace_noflag_bad_c.cpp
@@ -9,7 +9,7 @@
 #include <verilated.h>
 #include <verilated_vcd_c.h>
 
-#include "Vt_trace_noflag_bad.h"
+#include VM_PREFIX_INCLUDE
 
 int main(int argc, char** argv) {
     std::unique_ptr<VerilatedContext> contextp{new VerilatedContext};
diff --git a/test_regress/t/t_trace_open_wrong_order_bad.cpp b/test_regress/t/t_trace_open_wrong_order_bad.cpp
index 9fac96261..fa899b799 100644
--- a/test_regress/t/t_trace_open_wrong_order_bad.cpp
+++ b/test_regress/t/t_trace_open_wrong_order_bad.cpp
@@ -9,7 +9,7 @@
 #include <verilated.h>
 #include <verilated_vcd_c.h>
 
-#include "Vt_trace_open_wrong_order_bad.h"
+#include VM_PREFIX_INCLUDE
 
 int main(int argc, char** argv) {
     VerilatedContext ctx;
diff --git a/test_regress/t/t_tri_inout.cpp b/test_regress/t/t_tri_inout.cpp
index 8ce735b75..812db4be0 100644
--- a/test_regress/t/t_tri_inout.cpp
+++ b/test_regress/t/t_tri_inout.cpp
@@ -4,7 +4,7 @@
 // without warranty, 2008 by Lane Brooks.
 // SPDX-License-Identifier: CC0-1.0
 
-#include "Vt_tri_inout.h"
+#include VM_PREFIX_INCLUDE
 
 VM_PREFIX* tb = nullptr;
 
diff --git a/test_regress/t/t_tri_pullup.cpp b/test_regress/t/t_tri_pullup.cpp
index f900d0b06..311c28744 100644
--- a/test_regress/t/t_tri_pullup.cpp
+++ b/test_regress/t/t_tri_pullup.cpp
@@ -4,7 +4,7 @@
 // without warranty, 2008 by Lane Brooks.
 // SPDX-License-Identifier: CC0-1.0
 
-#include "Vt_tri_pullup.h"
+#include VM_PREFIX_INCLUDE
 
 VM_PREFIX* tb = nullptr;
 
diff --git a/test_regress/t/t_tri_select.cpp b/test_regress/t/t_tri_select.cpp
index b3fc80f98..fbea109aa 100644
--- a/test_regress/t/t_tri_select.cpp
+++ b/test_regress/t/t_tri_select.cpp
@@ -3,7 +3,7 @@
 // any use, without warranty, 2020 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
-#include "Vt_tri_select.h"
+#include VM_PREFIX_INCLUDE
 
 VM_PREFIX* tb = nullptr;
 
diff --git a/test_regress/t/t_var_overwidth_bad.cpp b/test_regress/t/t_var_overwidth_bad.cpp
index 5a4158ca8..053be27da 100644
--- a/test_regress/t/t_var_overwidth_bad.cpp
+++ b/test_regress/t/t_var_overwidth_bad.cpp
@@ -11,7 +11,7 @@
 
 #include "verilated.h"
 
-#include "Vt_var_overwidth_bad.h"
+#include VM_PREFIX_INCLUDE
 
 //======================================================================
 
diff --git a/test_regress/t/t_vpi_cb_iter.cpp b/test_regress/t/t_vpi_cb_iter.cpp
index d7b4d932e..d98fe968c 100644
--- a/test_regress/t/t_vpi_cb_iter.cpp
+++ b/test_regress/t/t_vpi_cb_iter.cpp
@@ -12,7 +12,8 @@
 #include "verilated.h"
 #include "verilated_vpi.h"
 
-#include "Vt_vpi_cb_iter.h"
+#include VM_PREFIX_INCLUDE
+
 #include "vpi_user.h"
 
 #include <cstdio>
diff --git a/test_regress/t/t_vpi_onetime_cbs.cpp b/test_regress/t/t_vpi_onetime_cbs.cpp
index c7632f8a9..dfd0106ed 100644
--- a/test_regress/t/t_vpi_onetime_cbs.cpp
+++ b/test_regress/t/t_vpi_onetime_cbs.cpp
@@ -23,7 +23,7 @@
 #include "verilated.h"
 #include "verilated_vpi.h"
 
-#include "Vt_vpi_onetime_cbs.h"
+#include VM_PREFIX_INCLUDE
 
 #endif
 
diff --git a/test_regress/t/t_vpi_repetitive_cbs.cpp b/test_regress/t/t_vpi_repetitive_cbs.cpp
index 84a82fa2c..aa4c0c204 100644
--- a/test_regress/t/t_vpi_repetitive_cbs.cpp
+++ b/test_regress/t/t_vpi_repetitive_cbs.cpp
@@ -20,7 +20,7 @@
 #include "verilated.h"
 #include "verilated_vpi.h"
 
-#include "Vt_vpi_repetitive_cbs.h"
+#include VM_PREFIX_INCLUDE
 #endif
 
 #include <cstdio>
diff --git a/test_regress/t/t_vpi_sc.cpp b/test_regress/t/t_vpi_sc.cpp
index 759d6075b..71f45e2aa 100644
--- a/test_regress/t/t_vpi_sc.cpp
+++ b/test_regress/t/t_vpi_sc.cpp
@@ -3,7 +3,7 @@
 // any use, without warranty, 2020 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
-#include "Vt_vpi_sc.h"
+#include VM_PREFIX_INCLUDE
 
 VM_PREFIX* tb = nullptr;