Any plan to support attributes like C++ `[[likely]]`, `[[unlikely]]`, and `[[cold]]`?

Evolution Discussion
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Compilers sometimes need some indications to optimize code more efficiently for hot/cold paths. I find [[likely]], [[unlikely]], and [[cold]]in C++ (cold is not standardized in C++ yet) and Rust (currently only support cold in Rust) useful. These attributes sometimes boost the performance more than 30% in my experience.

Swift compiler is powerful enough, but I am wondering if Swift eventually supports these attributes in the future.

Any insight is appreciated. I’d love to know if it’s a good/bad idea to add.

References

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Swift already have some methods public func _fastPath(_ x: Bool) -> Bool, public func _slowPath(_ x: Bool) -> Bool, public func _onFastPath(), though they are underlined and not included in the documentation. Perhaps we could propose making them public.

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I didn’t know that! That would be awesome if they become public.

I’d appreciate it if you or someone keep us updated when the proposal is created.

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Or am I even allowed to make an official proposal? I'm not a Swift contributor or anything though.