Heading home from PLDI26. Met great people, learned tons of stuff, and I feel very inspired! Wish I had attended PLDI conference sooner

Is a module system "export control"?

PLDI people tell me that Neil Jones never actually landed on the moon. It was staged

Great PLDI paper about verifying TikTok's compiler called UnAlive2

Is PLDI going well? Well, I convinced someone to implement linear scan register allocation in datalog,

Is formal methods for LLMs "model checking"?

If I had a nickel for every programming language implementation funded by ill-gotten World of Warcraft hacking gains, I'd have 1. Which isn't a lot, but it's still surprising

Back in my day it was an Ocean of Nodes. Now because of global warming it's a Sea of Nodes

On Monday morn I'll be giving a talk at @sigplan-pldi.bsky.social #PLDI EGRAPHS 2026 about lifting egraphs pldi26.sigplan.org/details/egra... a new twist on adding a notion of rigid alpha canonical variables to e-graphs! Pretty pumped about these ideas! Check it out!

New post: Test-case Reducers Are Underappreciated Debugging Tools. The more I've used these tools, the more ways I realise they can be used! This post starts at the basics and works up to things like reducing on properties other than just the length of the input. tratt.net/laurie/blog/...

Also forgot to mention some small fun with Z3 bernsteinbear.com/blog/asm-z3/

Inlining: the hard parts bernsteinbear.com/blog/inlinin...

I just blogged: 'Knownbits in Lean' cfbolz.de/posts/2026-k...

Incredibly fortunate to have noticed that a Joe's pizza opened in my neighborhood, gone in, gotten a slice, and learned that it opened today!!! Life is good

Probably silly but I'm really proud of this PR. It was challenging, fun to work on, and I think it'll have a big impact long term. 🤞 github.com/ruby/ruby/pu...

New linear scan register allocator in ZJIT by @tenderlove.dev ! railsatscale.com/2026-05-27-a...

Z3! You're on WATCH! Latest update to lean.py is a drop in replacement for Z3! Everyone's trying to put SMT solvers in their theorem prover, how about putting a theorem prover in your SMT solver? and here's the crazy thing: One click install, if you know Z3, you KNOW lean.py. You are not ready.

Please help Linda, my hairdresser gofund.me/f753af3c7

I try to sell one (1) thing on Poshmark and all of a sudden I am drowning in spam and phishing. What the heck

Have just gone to the shop to buy Triscuits—or as I like to call them, Wheat Thicks

I got unreasonably attached to Quip when working at FB. Can't believe Salesforce is shutting it down. :(

The program of ICOOOLPS is now online: 2026.ecoop.org/home/ICOOOLP... And today is the last day for early registrations. Interested in programming language implementation, compilation, and optimization? Join us in Brussels! Don't know what to expect? 1/2

I finally wrote a little thing about a compiler thing that I don't really have a name for but lots of people do bernsteinbear.com/blog/partial...

If you have not been to The Helmand in Cambridge, you simply must go at once. Their food is always spectacular but I was there again last night and the guy who makes their fresh bread just kept delivering us fresh bread straight from the oven with a huge smile every time. 1/

enjoy 2 new blog posts! - Porffor now has closures: surprisingly annoying for a compiler. goose.icu/porffor-clos... - Profile-guided dead code elimination: a novel approach for DCE in dynamic languages. goose.icu/profile-guid...

Bumping this thread: is this separation logic? Some local reasoning thing? It feels very Hoare triple but I actually can't find anything about this because I have no idea what I'm talking about

People keep saying stuff like "Ruby is a Smalltalk" so I think it would be fun to implement a Smalltalk with Ruby syntax. Or on top of Ruby VM. Or both?

To make it easier esp. for junior folks (students, postdocs, jr faculty) to talk to me, I'm trying a new thing: open office hours at conferences! Come find me at PLDI 2026, using the public calendar linked to the page below. Please feel free to reshare! cs.brown.edu/people/sk/Co...

I have somehow accidentally substantially broken the laundry machine in this very nice hotel by feeding it a 50 Yen coin. Two men are currently arguing about how to fix it. :(

the first rule of compilers is to have fun

New blog post: Theseus, a static Windows emulator An new old approach to emulation. neugierig.org/software/blo...

First "perfect week" since December 2024 :)

Hi! We build fast verilog simulators using just in time compilation. Our simulator outperforms existing verilog simulators by up to x100. verijit is a project by @cfbolz.bsky.social and Can Joshua Lehmann. Check out out demo video here: www. youtube.com/watch?v=PXgUsEjvAOY

C interpreters underlie many of our most widely used language implementations -- but they're slow. Wouldn't it be great if we could turn them into JIT compiling VMs? This video shows what happens when we do just that to the normal Lua VM (first) and "yklua" (Lua w/JIT, second).

In which I finally make sense of value numbering bernsteinbear.com/blog/value-n...

If – on this grey Sunday morning – you would like to read a dozen pages about using tail calls for fast interpreters, then I have Excellent News for you: www.mattkeeter.com/blog/2026-04...

In which I finally make sense of value numbering bernsteinbear.com/blog/value-n...

This is such an ingenious Apr 1st PR from Stephen Dolan I feel like it's the exact opposite of AI slop github.com/ocaml/ocaml/...

Perfetto is pretty neat railsatscale.com/2026-03-27-u...

New textbook cover?

New post by Jacob about recent heap modeling optimizations in ZJIT :D railsatscale.com/2026-03-18-h...

One more time — I'm looking for new consulting clients. Some ways I can help: ∙ Fractional tech leadership (tackling "leadership debt" in small eng orgs) ∙ Full-stack, 0 to 1 projects ∙ Language design & impl (eg with @ohmjs.org) ∙ JavaScript/TypeScript perf (🔁 appreciated)

Sharon Korean Kitchen in Boston is great. Stumbled across it and thoroughly enjoyed. Vegetarian friendly, too

The Swift Performance team isn’t *my* team, but they’re in my hallway. Or in London if you’d prefer. They’re looking for an engineer who’s not afraid of optimizers. jobs.apple.com/en-us/detail...

I wrote a tiny vectorized interpreter last night, and .. thought I'd write up a post describing it. Nothing earth shattering here, but if you haven't seen one of these before it could be interesting! Probably easier to read than the J Incunabulum, but also less .. wow. github.com/frankmcsherr...

I wrote a little extremely DIY fuzzer for the load/store optimization in the toy optimizer! bernsteinbear.com/blog/toy-fuz...

So my friend Chris taught me what byte pair encoding is and then I was idly thinking about it and I wonder if people can/do use this for generating bytecode interpreter superinstructions.

I wrote a little extremely DIY fuzzer for the load/store optimization in the toy optimizer! bernsteinbear.com/blog/toy-fuz...

It's actually by MarshDeer: marshdeer.github.io/xkcd2501-gen...