[llvm] [utils][UpdateLLCTestChecks] Add MIR support to update_llc_test_checks.py. (PR #164965)

[Valery Pykhtin via llvm-commits]

================
@@ -16,6 +16,7 @@
 import sys
 
 from UpdateTestChecks import common
+import update_mir_test_checks  # Reuse MIR parsing code.
----------------
vpykhtin wrote:

Thanks, done. Probably would be nice to move MIR specific code to the new _mir.py_, part of MIR code was already moved into _common_ in #140296.

https://github.com/llvm/llvm-project/pull/164965