[llvm] [Utils][update_mc_test_checks] Support updating round-trip tests. (PR #164425)

[Ivan Kosarev via llvm-commits]

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@@ -24,12 +24,24 @@
 OUTPUT_SKIPPED_RE = re.compile(r"(.text)")
 COMMENT = {"asm": "//", "dasm": "#"}
 
+SUBSTITUTIONS = {
+    "%extract-encodings": "sed -n 's/.*encoding://p'",
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kosarev wrote:

It's been in use since months ago, no complaints so far I'm aware of. Lots of tests seem to use sed, including some invoking sed -n specifically.

https://github.com/llvm/llvm-project/pull/164425