this post was submitted on 17 Nov 2023
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Programming
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The point is that if the predicate is evaluated at runtime then the compiler plays no role because there is no compile-time constant and all code paths are deemed possible.
I understand that you're trying to say that compilers can leverage compile-time constants to infer if code paths are dead code or not.
That's just a corner case though. Your compiler has no say on what code paths are dead if you're evaluating a predicate from, say, the response of a HTTP request. It doesn't make sense to expect this hypothetical scenario to be realistic when you have no info on where a predicate is coming from.
They're talking about moving the calculation of the if condition outside of the loop. Which the original commenter mentioned. https://en.m.wikipedia.org/wiki/Loop-invariant_code_motion
You are the one that brought up dead code elimination.