[Dylan16807]

> If foo is false in your code, then the behavior is completely defined.

That's the point. If foo is false, both versions do the same thing. If foo is true, then it's undefined and it doesn't matter. Therefore, assume foo is false. Remove the branch.

[myrryr]

Yes! This is exactly the point. It is undefined, so given that, it could do what the other branch does, so you can safely remove that branch.

you get it, but a lot of other people don't understand just how undefined, undefined code is.

[SonOfLilit]

We do. We just wish undefined was defined to be a bit less undefined, and are willing to sacrifice a bit of performance for higher debuggability an. ability to reason.

[uecker]

Why not use -fsanitize=signed-integer-overflow ?

[Dylan16807]

It could do what the other branch does, in theory.

But let me put it this way. If you only had the misbehaving_code(); line by itself, the compiler would rightly be called crazy and malicious if it compiled that to delete_data();

So maybe it's not reasonable to treat both branches as having the same behavior, even if you can.