diff --git a/llvm/utils/lit/lit/run.py b/llvm/utils/lit/lit/run.py
--- a/llvm/utils/lit/lit/run.py
+++ b/llvm/utils/lit/lit/run.py
@@ -186,17 +186,14 @@
             self.hit_max_failures = True
 
 def _execute_test_impl(test, lit_config, parallelism_semaphores):
-    """Execute one test"""
+    """Execute one test with the appropriate level of parallelism"""
     pg = test.config.parallelism_group
     if callable(pg):
         pg = pg(test)
 
-    result = None
-    semaphore = None
     try:
         if pg:
             semaphore = parallelism_semaphores[pg]
-        if semaphore:
             semaphore.acquire()
         start_time = time.time()
         result = test.config.test_format.execute(test, lit_config)
@@ -218,7 +215,7 @@
         output += '\n'
         result = lit.Test.Result(lit.Test.UNRESOLVED, output)
     finally:
-        if semaphore:
+        if pg:
             semaphore.release()
 
     test.setResult(result)