John Regehr

@regehr
5K Followers
977 Following
4.6K Posts
he/him
professional interestscompilers, software testing, fuzzing, formal verification, lowkey shitposting, mountains, deserts, cats
my pagehttps://john.regehr.org/
sigh.... @DRMacIver...

the instructions for my headlamp indicate that if you have a sweet stache and a choking fetish, then you must pay close attention

alt: pretty much as described 😬

this looks exciting! David is incredibly good at what he does (tool support for property-based testing and test case reduction)

https://antithesis.com/blog/2026/hegel/

Hypothesis, Antithesis, synthesis

Introducing Hegel, our new family of property-based testing libraries.

weird. I thought zuckerberg was still trying to convince us that he's a real boy.

https://www.the-independent.com/tech/mark-zuckerberg-ai-ceo-bot-b2943792.html

Mark Zuckerberg builds AI CEO to help him run Meta

Tech giant’s tools include ‘Second Brain’ and an internal messaging board for AI bots

The Independent
New research from UW exposes what it's really like to be under ICE's compulsory surveillance app, BI SmartLINK. The findings are alarming and the researchers conclude the app simply should not be used. 🧵

some nice followup to my group's (non-LLM) work on generalizing peephole optimizations. the non-LLM side of program synthesis really does seem to be dead at this point.

https://arxiv.org/pdf/2603.18477

here's the verified popcount with efficient extracted code if anyone's curious https://github.com/regehr/lean4-popcount/tree/main
May you live in interesting times... https://no01.substack.com/p/march-19-21-god-is-a-comedian Three weeks into the Iran war, reality has passed through the looking glass, out the other side, and is now selling tickets to the gift shop. What follows is not satire. Satire requires exaggeration, and you cannot exaggerate something that is already operating at maximum absurdity. This is simply the news, and nothing but the news. Told straight, in a universe that has clearly stopped taking its medication.
March, 19-21: God is a comedian

A stiff drink is recommended

Gold and Geopolitics