llvm.expect as intrinsics and use it in assert!-like macros #8291
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Add two functions to std::unstable::intrinsics module: expect{32,64}
provide access to llvm.expect.{32,64}.
Add `likely` and `unlikely` wrappers to intrinsics module.
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I'm always skeptical about adding features that don't provide any visible advantage. Why do it? Adding these branch annotations has a pretty notorious reputation in the linux kernel, where they are very often wrong. Future maintainers will see this and assume it was done for a reason, but what is it? |
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@brson probably you are right, discarding pull request. |
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I actually need this for something, but LLVM lowers the |
flip1995
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Sep 9, 2022
add `--explain` subcommand This closes rust-lang#8291. --- changelog: add `cargo clippy -- --explain <lintname>` subcommand
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Two patches:
1
access
llvm.expect.32andllvm.expect.64intrinsics asexpect32andexpect64functions instd::unstable::intrinsicsmodule. Module also haslikelyandunlikelywrappers.2
Use
expect32function in assert!-like macros.The patch doesn't provide any visible speed-up, but at least it shouldn't make things worse.