diff --git a/test_regress/t/t_unopt_combo.pl b/test_regress/t/t_unopt_combo.pl
index 0583bc033..80b42932e 100755
--- a/test_regress/t/t_unopt_combo.pl
+++ b/test_regress/t/t_unopt_combo.pl
@@ -8,7 +8,7 @@ if (!$::Driver) { use FindBin; exec("./driver.pl", @ARGV, $0); die; }
 # General Public License or the Perl Artistic License.
 
 compile (
-	 v_flags2 => ['-DALLOW_UNOPT'],
+	 v_flags2 => ['+define+ALLOW_UNOPT'],
 	 );
 
 execute (
diff --git a/test_regress/t/t_unopt_combo.v b/test_regress/t/t_unopt_combo.v
index 48e098804..1c5abae61 100644
--- a/test_regress/t/t_unopt_combo.v
+++ b/test_regress/t/t_unopt_combo.v
@@ -91,11 +91,16 @@ module file (/*AUTOARG*/
 	end
 	default: begin
 	   b = ~crc;
-	   d = ~c;
+	   set_d(~c); // d = ~c;
 	end
       endcase
    end
 
+   task set_d;
+      input [31:0] to;
+      d = to;
+   endtask
+
    always @* begin
       // Any complicated equation we can't optimize
       casez (crc[3:0])
diff --git a/test_regress/t/t_unopt_combo_isolate.pl b/test_regress/t/t_unopt_combo_isolate.pl
index ab7217dd8..4a45d8da2 100755
--- a/test_regress/t/t_unopt_combo_isolate.pl
+++ b/test_regress/t/t_unopt_combo_isolate.pl
@@ -10,7 +10,7 @@ if (!$::Driver) { use FindBin; exec("./driver.pl", @ARGV, $0); die; }
 top_filename("t/t_unopt_combo.v");
 
 compile (
-	 v_flags2 => ['-DISOLATE --stats'],
+	 v_flags2 => ['+define+ISOLATE --stats'],
 	 );
 
 if ($Last_Self->{v3}) {