diff --git a/test_regress/t/t_gantt_io.pl b/test_regress/t/t_gantt_io.pl
index 9a5924c8a..ba111c47f 100755
--- a/test_regress/t/t_gantt_io.pl
+++ b/test_regress/t/t_gantt_io.pl
@@ -11,12 +11,12 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(dist => 1);
 
 run(cmd => ["cd $Self->{obj_dir} && $ENV{VERILATOR_ROOT}/bin/verilator_gantt"
-            . " $Self->{t_dir}/t_gantt_io.dat > gantt.log"],
+            . " $Self->{t_dir}/$Self->{name}.dat > gantt.log"],
     check_finished => 0);
 
 files_identical("$Self->{obj_dir}/gantt.log", $Self->{golden_filename});
 
-vcd_identical("$Self->{obj_dir}/profile_threads.vcd", "$Self->{t_dir}/t_gantt_io_vcd.out");
+vcd_identical("$Self->{obj_dir}/profile_threads.vcd", "$Self->{t_dir}/$Self->{name}.vcd.out");
 
 ok(1);
 1;
diff --git a/test_regress/t/t_gantt_io_vcd.out b/test_regress/t/t_gantt_io.vcd.out
similarity index 100%
rename from test_regress/t/t_gantt_io_vcd.out
rename to test_regress/t/t_gantt_io.vcd.out
diff --git a/test_regress/t/t_gantt_io_noproc.dat b/test_regress/t/t_gantt_io_noproc.dat
new file mode 100644
index 000000000..423d57a05
--- /dev/null
+++ b/test_regress/t/t_gantt_io_noproc.dat
@@ -0,0 +1,24 @@
+VLPROFTHREAD 1.1 # Verilator thread profile dump version 1.1
+VLPROF arg --threads 2
+VLPROF arg +verilator+prof+threads+start+2
+VLPROF arg +verilator+prof+threads+window+2
+VLPROF stat yields 0
+VLPROF eval start 595 elapsed 11655 cpu 19 on thread 1
+VLPROF eval_loop start 945 elapsed 11235 cpu 19 on thread 1
+VLPROF mtask 6 start 2695 elapsed 210 predict_start 0 predict_cost 30 cpu 19 on thread 1
+VLPROF mtask 10 start 9695 elapsed 175 predict_start 196 predict_cost 30 cpu 19 on thread 1
+VLPROF eval start 13720 elapsed 8610 cpu 19 on thread 1
+VLPROF eval_loop start 14000 elapsed 8085 cpu 19 on thread 1
+VLPROF mtask 6 start 15610 elapsed 210 predict_start 0 predict_cost 30 cpu 19 on thread 1
+VLPROF mtask 10 start 21700 elapsed 175 predict_start 196 predict_cost 30 cpu 19 on thread 1
+VLPROF mtask 5 start 5495 elapsed 595 predict_start 0 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 7 start 6300 elapsed 595 predict_start 30 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 8 start 7490 elapsed 1050 predict_start 60 predict_cost 107 cpu 10 on thread 2
+VLPROF mtask 9 start 9135 elapsed 595 predict_start 167 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 11 start 10255 elapsed 805 predict_start 197 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 5 start 18375 elapsed 595 predict_start 0 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 7 start 19145 elapsed 175 predict_start 30 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 8 start 19670 elapsed 140 predict_start 60 predict_cost 107 cpu 10 on thread 2
+VLPROF mtask 9 start 20650 elapsed 70 predict_start 167 predict_cost 30 cpu 10 on thread 2
+VLPROF mtask 11 start 21140 elapsed 105 predict_start 197 predict_cost 30 cpu 10 on thread 2
+VLPROF stat ticks 23415
diff --git a/test_regress/t/t_gantt_io_noproc.out b/test_regress/t/t_gantt_io_noproc.out
new file mode 100644
index 000000000..87680d43c
--- /dev/null
+++ b/test_regress/t/t_gantt_io_noproc.out
@@ -0,0 +1,36 @@
+Verilator Gantt report
+
+Argument settings:
+  +verilator+prof+threads+start+2
+  +verilator+prof+threads+window+2
+  --threads 2
+
+Analysis:
+  Total threads             = 2
+  Total mtasks              = 7
+  Total cpus used           = 2
+  Total yields              = 0
+  Total evals               = 2
+  Total eval loops          = 2
+  Total eval time           = 21875 rdtsc ticks
+  Longest mtask time        = 1190 rdtsc ticks
+  All-thread mtask time     = 5495 rdtsc ticks
+  Longest-thread efficiency = 5.4%
+  All-thread efficiency     = 12.6%
+  All-thread speedup        = 0.3
+
+Prediction (what Verilator used for scheduling):
+  All-thread efficiency     = 63.2%
+  All-thread speedup        = 1.3
+
+Statistics:
+  min log(p2e) = -3.681  from mtask 5 (predict 30, elapsed 1190)
+  max log(p2e) = -2.409  from mtask 8 (predict 107, elapsed 1190)
+  mean = -2.992
+  stddev = 0.459
+  e ^ stddev = 1.583
+
+CPUs:
+  cpu 10: cpu_time=4725
+  cpu 19: cpu_time=770
+
diff --git a/test_regress/t/t_gantt_io_noproc.pl b/test_regress/t/t_gantt_io_noproc.pl
new file mode 100755
index 000000000..f3011e1ff
--- /dev/null
+++ b/test_regress/t/t_gantt_io_noproc.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(dist => 1);
+
+run(cmd => ["cd $Self->{obj_dir} && $ENV{VERILATOR_ROOT}/bin/verilator_gantt"
+            . " --no-vcd $Self->{t_dir}/$Self->{name}.dat > gantt.log"],
+    check_finished => 0);
+
+files_identical("$Self->{obj_dir}/gantt.log", $Self->{golden_filename});
+
+ok(1);
+1;