> it could very well have the same behavior emerge from compiler optimization passes. It can not, because "compiler optimization passes" is not the root cause

> it could very well have the same behavior emerge from compiler optimization passes. It can not, because "compiler optimization passes" is not the root cause of this behavior: it is that it is undefined behavior in the language itself. This is what gives the compiler license to make those transformations. In Rust, it is not undefined behavior, and therefore the compiler does not have the right to make those transformations for Rust code. Just because Rust uses LLVM does not mean that suddenly it inherits C's semantics. This has actually happened (well, more specifically, C++'s semantics, C was accidentally inheriting them as well IIRC) at least one time before, but that is a bug in LLVM that was fixed. Now each language has the proper semantics here, and it all works just fine. (I am referring to the behavior with regards to infinite loops with no side effects.)