update_llc_test_checks.py crashes when trying to add checks to a newly created test file

[Poseydon42]

The update_llc_test_checks.py script crashes when generating check lines for the first time if the file does not have a ; RUN ... line at the top. The error message is below:

Traceback (most recent call last):
  File "/home/poseydon/dev/llvm-project/./llvm/utils/update_llc_test_checks.py", line 285, in <module>
    main()
  File "/home/poseydon/dev/llvm-project/./llvm/utils/update_llc_test_checks.py", line 240, in main
    output_type.add_checks(
UnboundLocalError: local variable 'output_type' referenced before assignment

Steps to reproduce:

1. Create a new .ll file in llvm/test/CodeGen/X86/
2. Add at least one function to it
3. Run update_llc_test_checks.py --llc-binary path/to/your/built/llc llvm/test/CodeGen/X86/your_file.ll

Can someone please confirm if this is indeed a bug or if the scripts isn't intended to be used without manually adding a ; RUN ... line first.