diff --git a/llvm/utils/lit/lit/builtin_commands/cat.py b/llvm/utils/lit/lit/builtin_commands/cat.py
index 6fb2152ef9332..d6dbe889cc2b1 100644
--- a/llvm/utils/lit/lit/builtin_commands/cat.py
+++ b/llvm/utils/lit/lit/builtin_commands/cat.py
@@ -10,7 +10,7 @@
 def convertToCaretAndMNotation(data):
     newdata = StringIO()
     if isinstance(data, str):
-        data = bytearray(data)
+        data = bytearray(data.encode())
 
     for intval in data:
         if intval == 9 or intval == 10: