No, deterministic means that given the same inputs—source code, target architecture, optimization level, memory and runtime limits (because if the optimizer has more space/time it might find better optimizations), etc—a compiler will produce the same exact output. This is what reproducible builds is about: tightly controlling the inputs so the same output is produced.

That a compiler might pick among different specific implementations in the same equivalency class is exactly what you want a multi-architecture optimizing compiler to do. You don't want it choosing randomly between different optimization choices within an optimization level, that would be non-deterministic at compile time and largely useless assuming that there is at most one most optimized equivalent. I always want the compiler to choose to xor a register with itself to clear it if that's faster than explicitly setting it to zero if that makes the most sense to do given the inputs/constraints.

Determinism may be required for some compiler use cases, such as reproducible builds, and several replies have pointed that out. My point isn't that determinism is unimportant, but that it isn't intrinsic to compilation itself.

There are legitimate compiler use cases e.g. search‑based optimization, superoptimization, diversification etc where reproducibility is not the main constraint. It's worth leaving conceptual space for those use cases rather than treating deterministic output as a defining property of all compilers

Don't LLMs create the same outputs based on the same inputs if the temperature is 0? Maybe I'm just misunderstanding.