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

[Carl Ritson via llvm-commits]

https://github.com/perlfu commented:

I think the substance of the change is good.  Sub/super register kills definitely need to be handled in this case.  This patch seems like a reasonable minimal change to address that need.

Can you add one further test that checks when the defs are super register and a kill is only for a sub register? I don't think existing tests cover this.

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