[masswerk]

Isn't there even a formal specification that hot code maintains values or-ed with zero internally as integers?

(I think, this had been originally introduced by Mozilla and propagated to other browsers to varying extent. This optimization allowed a significant speed up for things like EMScripten before WASM.)

[ygra]

Yes, asm.js, which by now has been abandoned and superseded by WebAssembly. And while Chrome never really supported asm.js, they added some optimizations that benefitted code written in that style.

I think that may also have been a problem with asm.js. While the code would work as is because it's just JS, you won't get any performance guarantees because the runtime could just do its own thing instead of doing ahead-of-time compilation to optimized code.

[masswerk]

ASM is what I was looking for – thank you!