[clang] [llvm] [CoroEarly] Infer presplitcoroutine attribute for Switch-Resumed ABI (PR #169866)

[Weibo He via llvm-commits]

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NewSigma wrote:

Hi @ChuanqiXu9, I noticed fixing the failing test breaks the behavior introduced in #49264. Specifically, there are two inconsistencies:

1. The O0 pipeline schedules AlwaysInliner before CoroEarly, while others schedule CoroEarly before AlwaysInliner.
2. Switch ABI requires the frontend to set the `presplitcoroutine` attribute, while other ABIs infer the attribute during CoroEarly. (I think they would suffer from bug #49264, though)

Is there a specific reason we do not promote CoroEarly ahead of AlwaysInliner? I'd appreciate any context on the current ordering.

https://github.com/llvm/llvm-project/pull/169866