Does real-world code loops so much in constexpr code that optimizing its evaluation is worth it?

If so, why invent another bytecode to do the evaluation, with the risk of introducing inconsistencies? Couldn’t they add a flag “must be fully constant folded” to the compiler intermediate code, and, if (likely) necessary, optimize the LLVM constant folding optimization passes?

As a bonus, that could help other languages with a LLVM backend that want to do similar stuff.