LLVM IR is an unstable format, changes a lot and only has one implementation.So it's not well suited for a standard. Google actually did use it for PNaCl but f

LLVM IR is an unstable format, changes a lot and only has one implementation.So it's not well suited for a standard. Google actually did use it for PNaCl but fortunately Mozilla prevailed when wasm was created. "Do what LLVM does" is not a valid strategy. On a related note, I'm glad that Firefox doesn't support the "Do what sqlite does" WebSQL api either, but Chrome (sadly) does.