But what does "mostly" mean? You can compile the same code twice and literally get two different binaries. The bits don't match.
Sure, those collections of bits tend to do exactly the same thing when executed, but that's is in some sense a subjective evaluation.
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Szundi said in a sibling comment that I was "completely [missing] the point on purpose" by bringing up compiler determinism. I think that's fair, but it's also why I opened my post by saying "I agree [with the parent], but I want to try to define the language better." Most compilers in use today are literally not deterministic, but they are deterministic in a different sense, which is useful as a comparison point to LLMs. Well, which sense? What is the fundamental quality that makes a compiler more predictable?
I'd like to try to find the correct words, because I don't think we have them yet.