To add on to what the others have said, the compiler will also optimise your code (which is why professional coders write in common patterns as much as possible, so the compiler can recognise them and optimise).

So many times, you literally won't even have the same program.

Also machine understandable code (assembly or 1s and 0s) is different depending on the processor used. You could give me machine code made for a risc-v processor and I could reconstruct a c program that made it. But if I had the same program compiled for an x86 processor ...