Viewing profile — nicula

Yeah it's quite interesting. I don't think I've seen this come up in anything besides that talk which is about the HFT space. However, I did hear a few times about cases where you'…

Great observations, thanks! I wrote the code that you suggested (LMK if I understood your points): https://godbolt.org/z/jW4o3cnh3 And here's the benchmark output, on my machine: h…

Thanks for looking into it! I modified the footnote to get rid of the misleading statements regarding the 'backfiring' of the optimization. :)

> I'm not sure how "it can go the other way around too" -- in that case (assigning to a uint8_t local variable), it seems like that particular optimisation is just not being applie…

Some people already mentioned this in the r/cpp discussion. Small correction: 256 is not the correct number of iterations, since if all elements in that slice are even, then your 8…

Like @wffurr mentioned, this is indeed discussed in a footnote. I just added another remark to the same footnote: "It's also debatable whether or not Clang's 'optimization' results…

haha I didn't even notice that

> So it's not a Clang regression per se, it's an issue with the LLVM core? Yes. > If you run LLVM 18's `opt` on bytecode generated by Clang 19 and then compile it, does it also gen…

This issue doesn't require large switch tables in order to show up. Even if you have 4 cases and the rest of them are default'ed, Clang 18 optimizes that to a switch, while Clang 1…

Oh wow didn't know about this. Somebody else posted it for me. Sorry for the dup:)