[llvm] added a script to update llvm-mc test file (PR #107246)

[Ivan Kosarev via llvm-commits]

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@@ -0,0 +1,5 @@
+; NOTE: Assertions have been autogenerated by utils/update_mc_test_checks.py
+// RUN: not llvm-mc -triple=amdgcn -show-encoding %s 2>&1 | FileCheck --check-prefixes=CHECK %s
+
+v_bfrev_b32 v5, v299
+// CHECK: error: register index is out of range
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kosarev wrote:

Daydreaming: I guess this could even do the `[[@LINE-1]]` thing?

https://github.com/llvm/llvm-project/pull/107246