Comment by dnautics
6 hours ago
Zig Comptime uses softfloat so it has architecture independent determinism.
And the zig core team is absolutely concerned with bitwise determinism in the compiled artifacts, iirc this is why they rejected the sloppy bun PR to the compiler.
Determinism and host/target agreement are two different properties.
The Zig core team is apparently not concerned enough about the second point to forbid transcendentals at comptime and this is something that'd be hard to take back, because I'd break existing code.
Generally speaking, as a user of a language, stuff should just work while providing identical results to the target arch.
Which means that when cross compiling from x86 to ARM, if lets say, transcendentals provide different results then always the target archs implementations should be used, even if they have to be emulated.
If however, hypothetically, different x86 CPUs produce different results for transcendentals, and we can't control where the user will run our program, then imo the correct solution for the language is to provide a set of knobs for the user to communicate whether they favor accuracy or speed in this scenario. - but we can say there's no 'correct' decision in this case, only tradeoffs.
Forbidding transcendentals is not a correct decision as it adds a ton of compiler complexity (you have to track which functions use them transitively), and baffling UX - the user finds that comptime doesn't work because the function he uses might use transcendentals somewhere down the chain.