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Clang/LLVM accepts (little-known but documented) flags to let you align code block using a custom alignment, though it only works at file-level. See [1].

However, I'm not sure if doing so is useful or necessary. Interpreter performance is sensitive to code layout (which affects hardware branch predictor accuracy), but I don't think there is a general way to optimize the code layout to make the branch predictor as happy as possible.

So if you changed your code alignment and saw a perf change, it's more likely caused by the random perf gain/loss due to code layout change, not because that 1-byte-alignment is better than 16-byte-alignment or vice versa.

[1] https://easyperf.net/blog/2018/01/25/Code_alignment_options_...



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