[clang] [Clang][CodeGen] Do not emit lifetime intrinsics for coro promise alloca (PR #140548)

[Hans Wennborg via cfe-commits]

zmodem wrote:

> If we add lifetimes to it, middle end passes may assume promise dead after lifetime.end, leading to mis-optimizations.

It sounds like the issue is that we emit *incorrect* lifetime intrinsics for it, not the lifetime intrinsics itself.

> Here is a example

Was that generated by Clang?

It would be good to have a small C++ example showing the incorrect lifetime intrinsics, that could also be used as a test.


https://github.com/llvm/llvm-project/pull/140548