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

[via llvm-commits]

zmodem wrote:

Is someone looking at doing the deeper fix to the lifetime analysis as suggested above, or should we do a stop gap fix in the meantime?

I'm not sure if the current patch is sufficient: it checks whether there is *a* lifetime.end intrinsic, but what if there is one on one execution path, but not another? Maybe we should always set ShouldUseLifetimeStartInfo to avoid this miscompile for now?

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