[remexre]

The problem is that LLVM IR makes breaking changes fairly frequently -- for instance, LLVM 15 made all pointers untyped; where before you'd have a type like *i32, now you just have ptr.

If you're trying to run the same IR on 32-bit and 64-bit devices, I'd expect you'd need to freeze the word size anyway -- if a C or C++ program uses sizeof(), what value gets returned?

Blocking IO doesn't get solved by switching to LLVM either; you can't block in browser WASM because it'd block the JS thread; a WASM engine not attached to a browser has no such issues. (I wish at least one-shot continuations would get added so that this could become a bit easier in the browser, but I understand the hesitancy to do so...)