[llvm] [MachineLateInstrsCleanup] Handle multiple kills for a preceding definition. (PR #119132)

[Jonas Paulsson via llvm-commits]

JonPsson1 wrote:

> > If there actually is a serious user, maybe that pass could instead recompute them and also be able to trust them fully.
> 
> No, there should be no users. All users should be changed to not rely on kill flags

There seems to be users in the Target backends - which could include late things like expandPostRAPseudo(), perhaps. There are also some use of isKill() in BranchFolding and probably other places. Do you think I could try to just remove kill flags a bit more carelessly ("ahead of time", even in the many cases where there is no following identical definition), and go ahead with this if no tests fail? Or are you saying there is some work left to be done in places that we should aim to do first?

https://github.com/llvm/llvm-project/pull/119132