Index: unittests/Support/DebugCounterTest.cpp
===================================================================
--- unittests/Support/DebugCounterTest.cpp
+++ unittests/Support/DebugCounterTest.cpp
@@ -18,6 +18,14 @@
               "Counter used for unit test");
 
 TEST(DebugCounterTest, CounterCheck) {
+  // Unfortunately, the CommandLineTest.GetCommandLineArguments test would
+  // unregister the global counter above.
+  if (!DebugCounter::instance().getCounterId("test-counter")) {
+    const_cast<unsigned &>(TestCounter) =
+        DebugCounter::instance().registerCounter("test-counter",
+                                                 "Counter used for unit test");
+  }
+
   EXPECT_FALSE(DebugCounter::isCounterSet(TestCounter));
 
   auto DC = &DebugCounter::instance();