diff --git a/test_regress/t/t_vpi_force.py b/test_regress/t/t_vpi_force.py
index 20ff5295c..11f04c31a 100755
--- a/test_regress/t/t_vpi_force.py
+++ b/test_regress/t/t_vpi_force.py
@@ -14,7 +14,10 @@ test.scenarios('simulator')
 test.compile(make_top_shell=False,
              make_main=False,
              make_pli=True,
-             verilator_flags2=["+define+VERILATOR_COMMENTS --binary --vpi", test.pli_filename],
+             verilator_flags2=[
+                 "+define+VERILATOR_COMMENTS --binary --vpi", test.build_jobs, "--CFLAGS -O0",
+                 test.pli_filename
+             ],
              v_flags2=["+define+USE_VPI_NOT_DPI"])
 
 test.execute(xrun_flags2=["+define+USE_VPI_NOT_DPI"], use_libvpi=True, check_finished=True)