diff --git a/test_regress/driver.pl b/test_regress/driver.pl
index c383747ed..94e2cd594 100755
--- a/test_regress/driver.pl
+++ b/test_regress/driver.pl
@@ -1219,7 +1219,7 @@ sub execute {
                    @{$param{iv_run_flags}},
                    @{$param{all_run_flags}},
                           );
-        if ($param{iv_pli}) {
+        if ($param{use_libvpi}) {
             # don't enter command line on $stop, include vpi
             unshift @cmd, "vvp -n -m $self->{obj_dir}/libvpi.so";
         }
@@ -1233,7 +1233,7 @@ sub execute {
     }
     elsif ($param{ms}) {
         my @pli_opt=();
-        if ($param{ms_pli}) {
+        if ($param{use_libvpi}) {
             unshift @pli_opt, "-pli $self->{obj_dir}/libvpi.so";
         }
         $self->_run(logfile=>"$self->{obj_dir}/ms_sim.log",
diff --git a/test_regress/t/t_dpi_arg_inout_type.pl b/test_regress/t/t_dpi_arg_inout_type.pl
index 4bdfdef91..9ca750797 100755
--- a/test_regress/t/t_dpi_arg_inout_type.pl
+++ b/test_regress/t/t_dpi_arg_inout_type.pl
@@ -37,7 +37,6 @@ if ($Self->{vlt_all}) {
 execute(
     check_finished => 1,
     expect_filename => $Self->{golden_filename},
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_arg_inout_unpack.pl b/test_regress/t/t_dpi_arg_inout_unpack.pl
index ec76ba91c..18dfa90cf 100755
--- a/test_regress/t/t_dpi_arg_inout_unpack.pl
+++ b/test_regress/t/t_dpi_arg_inout_unpack.pl
@@ -36,7 +36,6 @@ if ($Self->{vlt_all}) {
 
 execute(
     check_finished => 1,
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_arg_input_type.pl b/test_regress/t/t_dpi_arg_input_type.pl
index 4bdfdef91..9ca750797 100755
--- a/test_regress/t/t_dpi_arg_input_type.pl
+++ b/test_regress/t/t_dpi_arg_input_type.pl
@@ -37,7 +37,6 @@ if ($Self->{vlt_all}) {
 execute(
     check_finished => 1,
     expect_filename => $Self->{golden_filename},
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_arg_input_unpack.pl b/test_regress/t/t_dpi_arg_input_unpack.pl
index ec76ba91c..18dfa90cf 100755
--- a/test_regress/t/t_dpi_arg_input_unpack.pl
+++ b/test_regress/t/t_dpi_arg_input_unpack.pl
@@ -36,7 +36,6 @@ if ($Self->{vlt_all}) {
 
 execute(
     check_finished => 1,
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_arg_output_type.pl b/test_regress/t/t_dpi_arg_output_type.pl
index 4bdfdef91..9ca750797 100755
--- a/test_regress/t/t_dpi_arg_output_type.pl
+++ b/test_regress/t/t_dpi_arg_output_type.pl
@@ -37,7 +37,6 @@ if ($Self->{vlt_all}) {
 execute(
     check_finished => 1,
     expect_filename => $Self->{golden_filename},
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_arg_output_unpack.pl b/test_regress/t/t_dpi_arg_output_unpack.pl
index ec76ba91c..18dfa90cf 100755
--- a/test_regress/t/t_dpi_arg_output_unpack.pl
+++ b/test_regress/t/t_dpi_arg_output_unpack.pl
@@ -36,7 +36,6 @@ if ($Self->{vlt_all}) {
 
 execute(
     check_finished => 1,
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_open_query.pl b/test_regress/t/t_dpi_open_query.pl
index 8a94dbf67..32c447dfd 100755
--- a/test_regress/t/t_dpi_open_query.pl
+++ b/test_regress/t/t_dpi_open_query.pl
@@ -29,7 +29,6 @@ compile(
 
 execute(
     check_finished => 1,
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_dpi_result_type.pl b/test_regress/t/t_dpi_result_type.pl
index 4bdfdef91..9ca750797 100755
--- a/test_regress/t/t_dpi_result_type.pl
+++ b/test_regress/t/t_dpi_result_type.pl
@@ -37,7 +37,6 @@ if ($Self->{vlt_all}) {
 execute(
     check_finished => 1,
     expect_filename => $Self->{golden_filename},
-    ms_pli => 0
     );
 
 ok(1);
diff --git a/test_regress/t/t_vpi_get.pl b/test_regress/t/t_vpi_get.pl
index dc126dc16..c3f9a81c0 100755
--- a/test_regress/t/t_vpi_get.pl
+++ b/test_regress/t/t_vpi_get.pl
@@ -23,7 +23,7 @@ compile(
 );
 
 execute(
-    iv_pli => 1,
+    use_libvpi => 1,
     check_finished => 1
 );
 
diff --git a/test_regress/t/t_vpi_get_public_rw_switch.pl b/test_regress/t/t_vpi_get_public_rw_switch.pl
index 8c11341ac..3a5cdf231 100755
--- a/test_regress/t/t_vpi_get_public_rw_switch.pl
+++ b/test_regress/t/t_vpi_get_public_rw_switch.pl
@@ -29,7 +29,7 @@ compile(
 );
 
 execute(
-    iv_pli => 1,
+    use_libvpi => 1,
     check_finished => 1
 );
 
diff --git a/test_regress/t/t_vpi_memory.pl b/test_regress/t/t_vpi_memory.pl
index c01c0b9ed..9b95b19c4 100755
--- a/test_regress/t/t_vpi_memory.pl
+++ b/test_regress/t/t_vpi_memory.pl
@@ -23,7 +23,7 @@ compile(
     );
 
 execute(
-    iv_pli => 1,
+    use_libvpi => 1,
     check_finished => 1
     );
 
diff --git a/test_regress/t/t_vpi_module.pl b/test_regress/t/t_vpi_module.pl
index 69d086d90..bee11c3f0 100755
--- a/test_regress/t/t_vpi_module.pl
+++ b/test_regress/t/t_vpi_module.pl
@@ -23,7 +23,7 @@ compile(
     );
 
 execute(
-    iv_pli => 1,
+    use_libvpi => 1,
     check_finished => 1
     );
 
diff --git a/test_regress/t/t_vpi_param.pl b/test_regress/t/t_vpi_param.pl
index f6900846a..e5c448b01 100755
--- a/test_regress/t/t_vpi_param.pl
+++ b/test_regress/t/t_vpi_param.pl
@@ -23,7 +23,7 @@ compile(
     );
 
 execute(
-    iv_pli => 1,
+    use_libvpi => 1,
     check_finished => 1
     );
 
diff --git a/test_regress/t/t_vpi_time_cb.pl b/test_regress/t/t_vpi_time_cb.pl
index b08bfa811..98dd60d00 100755
--- a/test_regress/t/t_vpi_time_cb.pl
+++ b/test_regress/t/t_vpi_time_cb.pl
@@ -21,8 +21,7 @@ compile(
     );
 
 execute(
-    iv_pli => 1,
-    ms_pli => 1,
+    use_libvpi => 1,
     check_finished => 1,
     all_run_flags => ['+PLUS +INT=1234 +STRSTR']
     );
diff --git a/test_regress/t/t_vpi_var.pl b/test_regress/t/t_vpi_var.pl
index 57c6f6cb7..e9f2bac65 100755
--- a/test_regress/t/t_vpi_var.pl
+++ b/test_regress/t/t_vpi_var.pl
@@ -21,7 +21,7 @@ compile(
     );
 
 execute(
-    iv_pli => 1,
+    use_libvpi => 1,
     check_finished => 1,
     all_run_flags => ['+PLUS +INT=1234 +STRSTR']
     );
diff --git a/test_regress/t/t_vpi_zero_time_cb.pl b/test_regress/t/t_vpi_zero_time_cb.pl
index 24ae29812..7906bed68 100755
--- a/test_regress/t/t_vpi_zero_time_cb.pl
+++ b/test_regress/t/t_vpi_zero_time_cb.pl
@@ -21,8 +21,7 @@ compile(
     );
 
 execute(
-    iv_pli => 1,
-    ms_pli => 1,
+    use_libvpi => 1,
     check_finished => 1,
     all_run_flags => ['+PLUS +INT=1234 +STRSTR']
     );