[OT] The Usual Arithmetic Confusions

[Dukc]

On Monday, 31 January 2022 at 08:38:28 UTC, Ola Fosheim Grøstad 
wrote:
> On Monday, 31 January 2022 at 07:33:00 UTC, Elronnd wrote:
>> I have no doubt it comes up _at all_.  What I am asking is 
>> that I do not believe it has an _appreciable_ effect on any 
>> real software.
>
> Not if you work around it, but ask yourself: is it a good idea 
> to design your language in such a way that the compiler is 
> unable to remove this:
>
> ```
> if (x < x + 1) { … }
> ```
>
> Probably not.

It is a good idea. You can manually optimise that `if` out if 
performance is important. Manual optimisation is a must to get 
performant code anyway so not really a big deal. In the opposite 
case we would have undefined behaviour at `@safe` code.

We have array bounds checks for the exact same reason. They do 
penaltise the performance a bit, but prevent undefined behaviour 
and can be manually optimised out when performace is more 
important than memory protection.