Comment by sarchertech

> Can you look at code today and predict what assembly a compiler will output to some high degree of accuracy?

Yeah a fair amount is the time. And when I can’t, I can predict what an unoptimized version of the assembly will look like.

And I know that the optimized assembly has a very very high likelihood of being semantically identical. And I know enough of the edge cases where the differences matter to know when I need to actually verify what’s coming out of the compiler.

Prompt instability (not even worrying about non-determinism ) ensures that asking for the same exact thing in very slightly different ways or with slightly different contexts will give you wildly different outputs that are not even close to semantically identical.