I agree that programmers care more about what actually happens (and they should, when performance matters!), but this kind of analysis also involves future chan

I agree that programmers care more about what actually happens (and they should, when performance matters!), but this kind of analysis also involves future changes to the compiler unless it's a one-time job. Which sometimes exists, so check the assembly there and do whatever you need. Straightforward and limited-scope code like nested functions tends to improve in performance over time, because it restricts possibilities better than goto. And it's more error-resistant to future changes for similar reasons. If your code has to last a while, you're probably better off having the safer one. Or maintain both, and use the safer one to validate the unsafe one, and choose based on benchmarks of the week - what was true when it was written could change with any version.