why golang not provide likely/unlikely syntax?

[cheng dong]

i see golang source ssa guess BranchLikely/BranchUnLikely, however we could not tell golang whether if is likely or unlikely. and looks the guess logic might be far away from real condition

[Ian Lance Taylor]

On Mon, Mar 20, 2023 at 9:17 AM cheng dong <qq451...@gmail.com> wrote:
>
> i see golang source ssa guess BranchLikely/BranchUnLikely, however we could not tell golang whether if is likely or unlikely. and looks the guess logic might be far away from real condition

We don't want to complicate the language. Also, surprisingly,
experience shows that programmers are often mistaken as to whether
branches are likely or not. Instead, we are investigating
profile-guided optimization to make those choices. See
https://go.dev/blog/pgo-preview.

Ian

[cheng dong]

pgo is great tool for optmize branch prediction, hope branch prediction feature merge into pgo as soon as possible