the vessel of morgannareading a thread on the musl mailing list with a patch replacing the iswalpha/iswpunct functions with a compressed LUT, the code is clever, functional *and* better for the common cases, but the submitters replies very strongly smell of chatbot slop :/
d@nny disc@ mc²@astraleureka what is a LUT
@hipsterelectron a lookup table
@astraleureka the facebook guy here saying yeah we decided to do things a nonstandard way https://www.openwall.com/lists/musl/2026/03/24/2 reminds me of zstd who has their own memcpy "WILDCPY" with safe 16 bytes of overwrite and then a week later i find they strictly benchmark in-memory
@astraleureka i do not buy the gcc hate
To see why that's the case, consider a large vector of capacity C.
getting paid the big bucks to consider a large vector of capacity C
@astraleureka i definitely call bullshit on this lowercase k. pretty sure that is doing induction and then changing the counting variable into a rational
@hipsterelectron ohhh this is the {re,m}alloc with feedback thread.. i have been at least partially following this and the amount of bikeshedding glazed my eyes. i do not understand the motivation for fuzzy chance of slightly more space being returned from an allocation request when in the vast majority of cases you're going to need a whole lot more code on the consumer side to handle those cases where you get back more than you requested, isn't that going to eat up the really small number of cycles you could potentially "save" in the rare chance that you do get an expandable slice of memory that isn't already bounded by other allocations
@astraleureka oooh i buy your framing i'll read
@astraleureka yes wtf lmao
@astraleureka i'm a huge believer in scoped allocators as a conceptual measure just bc it's technically more information for the allocator to have a tagged set of users. but i also think i want a slightly more thoughtful and extensible way to handle those guarantees beyond rust's single scope at a time. i have been surprised that non lexical lifetimes were a solution to a problem
@astraleureka everything the fb guy is saying is weird and the intrinsic mention is funny when rust has this guy from google going yeah we do this crazy specific thing in llvm it's in the file that doesn't exist
Andrea (Drea) Tamar Pinski@hipsterelectron @astraleureka This is even true in GCC.
Though GCC does not do this: "The C intrinsics work around this by reversing the element ordering in vectors before & after each intrinsic" Instead it only swaps around the inserts/extracts for generic vectors.
Though GCC does not do this: "The C intrinsics work around this by reversing the element ordering in vectors before & after each intrinsic" Instead it only swaps around the inserts/extracts for generic vectors.
@pinskia @hipsterelectron how bad is the extra swapping in terms of instruction count? probably not *that* bad but has to hurt a little bit
@pinskia @astraleureka he didn't point to a real file!!! it is generated by the build system and does not seem to work this way. i would indeed be very glad to have one fewer thing to worry about and one more to learn about
@pinskia @astraleureka i do like being able to breathe
@pinskia @astraleureka that's why i found it such a dissatisfying explanation i didn't know at all how abstract it was