Integer overflow and underflow semantics?

[via Digitalmars-d]

On Sunday, 20 July 2014 at 11:09:45 UTC, Tobias Müller wrote:
> "Marc Schütz" <schuetzm at gmx.net> wrote:
>> On Saturday, 19 July 2014 at 19:49:24 UTC, Ola Fosheim Grøstad 
>> wrote:
>>> On Saturday, 19 July 2014 at 08:34:39 UTC, Kagamin wrote:
>>>> Can't it simply generate code as is? Seems wasteful to spend
>>>> >> compilation time on this.
>>> 
>>> Not if you want fast code, consider a template with:
>>> 
>>> if (a.length+M < b.length+N) {}
>>> 
>>> then you alias b = a in the template instantiation:
>>> 
>>> if(a.length+M < a.length+N){}
>>> 
>>> you want this reduced to:
>>> 
>>> if (M<N){
>>> }
>>> 
>>> which can be resolved at compile time.
>> 
>> Yes, but that is the optimizer's job. The front-end doesn't 
>> need to spend
>> time on it, if the back-end then anyway does the same 
>> optimization again.
>
> I don't think anyone has said that the frontend does that.

I do ;-) This is how I interpret Kagamin's post.