[llvm] [DSE] Mark promise of pre-split coroutine visible to caller (PR #133918)

[via llvm-commits]

NewSigma wrote:

> Out of curiosity, what's the corresponding pattern in C++ side? I mean, how can we see such pattern before coro-split?

Coro result object conversion function that attempts to modify the promise shall produce the pattern.

https://github.com/llvm/llvm-project/pull/133918