[llvm] [LLVM][Coroutines] Introduce TBAA metadata for coro frame object (PR #176543)

[Chuanqi Xu via llvm-commits]

ChuanqiXu9 wrote:

> If we look at this from a more theoretical standpoint, then using TBAA for this is not the correct approach. What we are attempting to do in this draft is tricking the AA to believe that the underlying types are not the same (even though they are). While these objects can never alias, it's not type based information that guarantees this. 

This may not be accurate. From C++'s perspective, the type of the coroutine frame of every coroutine function is a half opaque type. We can interpret this as the type of every coroutine frame is unique.

https://github.com/llvm/llvm-project/pull/176543