[llvm] [AMDGPU] Detect renamable kills when trying to form V_CMPX instructions. (PR #68293)

[Thomas Symalla via llvm-commits]

tsymalla wrote:

> I don't think this has anything to do with "renamable" does it? The test case should still provoke the bug even if you remove all the "renamable" flags.

It rather has to do with the register being contained in the set of the registers to be killed, right. I'll adjust the check.

https://github.com/llvm/llvm-project/pull/68293