Notices by John Regehr (regehr@mastodon.social)

@lzg antidotes to the woke mind virus

@lzg yes I’ll have a Moscone Calzone please

@lzg feeling attacked

@pinskia @dave_andersen yeah.. you have to also make i a 32-bit type instead of a 64-bit type (but long was 32 bits at the time this code was written, so that's reasonable)

@pinskia @dave_andersen I find "long" to be a weird choice in the original code, I wonder why they used that instead of int?

@dave_andersen it's always strict aliasing

it was not my intent for this to become an "optimizing Brainfuck" account. this will stop soon.

I wasn't sure how much it would matter to vectorize scan loops such as [<] and [>>] in Brainfuck, but on my M1 Mac I'm seeing dbfi.b going about 10x faster due to just this one optimization

http://www.hevanet.com/cristofd/08.html

@tommythorn
but so far in class we've only targeted native assembly. once we're done with this, we'll retarget everything to LLVM and pick up for free all of those amazing low-level optimizations that are too numerous for us to do by hand

@tommythorn ah, impossible to say without having worked on the other thing as well. what I can say about BF is that it's a bit a sweet spot for a compilers class because it has plenty of low-hanging optimizations, but they mostly require BF-specific knowledge, so for example LLVM alone would not be able to pick up most of these benefits.

@resistor hoo boy. I want to say I'd use this in a performance comparison but LLVM 2.8 or whatev is pretty distant now

@resistor one of the enterprising students in my class is attacking the problem that ~35% of LLVM unit tests trigger UB. 🤪 for real.

@dev but it would be more fun using a real pumpkin instead of a can!

@dev woah

@dev I made this last night with fresh tomatoes and the sauce really was better than with canned ones but damn it was basically like 2 hours

https://www.seriouseats.com/pasta-with-vodka-sauce

@dev well a pumpkin is a decoration until you decide to eat it, so that doesn't even count as taking up space!

"One Collatz Coincidence"

this is weird!

https://www.sligocki.com//2024/09/20/collatz-coincidence.html

one of my students wrote their Brainfuck interpreter in Uiua 👀

three-deep nested parentheses in regular prose or GTFO

it's fun to see Nikita throwing some shade on LLVM's original link-time optimization scheme

https://www.npopov.com/2023/04/07/LLVM-middle-end-pipeline.html

I used to, about once a year, try to build GCC using GCC's link-time optimizer and LLVM using LLVM's link-time optimizer, and this almost always failed for one reason or another...