[llvm] [CodeGen] DetectDeadLanes: do not rewrite operand flags on bundles (PR #222124)

[Kevin McAfee via llvm-commits]

kalxr wrote:

>Has this been superseded by https://github.com/llvm/llvm-project/pull/220645?

No, that patch identified the same problem but took the approach that I argued against:

>Rewriting the bundled instructions would not be correct either: bundle internal reads are ignored by MachineOperand::readsReg(), so an internal def only used inside the bundle would be marked dead.

@jakemdaly do you agree that this is an issue? This PR would basically nullify your change.

https://github.com/llvm/llvm-project/pull/222124