[llvm] Add metadata pointer regex substitution to MIR update script (PR #163253)

[Joe Nash via llvm-commits]

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@@ -247,6 +249,14 @@ def update_test_file(args, test, autogenerated_note):
             common.warn("No triple found: skipping file", test_file=test)
             return
 
+        # Replace metadata pointer values inserted by LLC with generic regex
+        # capturing the pointer's format so that stale values don't break tests
+        no_pointer_output = ""
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Sisyph wrote:

I don't have a strong opinion on this placement, but how did you decide at which point in the update script workflow to do this substitution. 

https://github.com/llvm/llvm-project/pull/163253