[llvm] [AMDGPU][MC] Fix disassembler warning for v_cmpx instructions in GFX9 (PR #163825)

[Shilei Tian via llvm-commits]

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@@ -0,0 +1,422 @@
+# RUN: llvm-mc -triple=amdgcn -mcpu=tonga -disassemble -show-encoding < %s | FileCheck -strict-whitespace %s
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shiltian wrote:

nit: auto generate check lines here and the other file using `llvm/utils/update_mc_test_checks.py`.

https://github.com/llvm/llvm-project/pull/163825