Re-implement likely/unlikely with #[cold]
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Since rust-lang/rust#120370 `#[cold]` affects branch weights in the backend (again?). Re-implement `likely` and `unlikely` in terms of a `#[cold]` function. You can verify that the LLVM IR in [this godbolt link](https://godbolt.org/z/n3v7hsMqK) contains a `branch_weights` metadata. These were removed in rust-lang@d677fd4.
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Since rust-lang/rust#120370
#[cold]affects branch weights in the backend (again?). Re-implementlikelyandunlikelyin terms of a#[cold]function.You can verify that the LLVM IR in this godbolt link contains a
branch_weightsmetadata.These were removed in d677fd4.