[llvm] [coroutines][CoroSplit] Store allocas on the frame if there is no explicit lifetime.end (PR #88806)

[Chuanqi Xu via llvm-commits]

ChuanqiXu9 wrote:

> I think the proposal is that we put all coroutine variables on the coroutine frame object rather than try to figure out what variables can go on the stack. This would generate suboptimal code, but it will be guaranteed to be correct.

Oh, it means to set `ShouldUseLifetimeStartInfo` to false. This change may have a large impact. Coroutines nowadays are used in many performance critical sections... we also need a RFC and call users to test the performance changes to do this...

Maybe we should try to look at how to fix it properly...

https://github.com/llvm/llvm-project/pull/88806