diff --git a/clang/utils/perf-training/perf-helper.py b/clang/utils/perf-training/perf-helper.py
--- a/clang/utils/perf-training/perf-helper.py
+++ b/clang/utils/perf-training/perf-helper.py
@@ -23,7 +23,7 @@
   filenames = []
   for root, dirs, files in os.walk(path): 
     for filename in files:
-      if filename.endswith(extension):
+      if os.path.splitext(filename)[1] == extension:
         filenames.append(os.path.join(root, filename))
   return filenames