Integer overflow and underflow semantics?

[Tobias Müller via Digitalmars-d]

"Marc Schütz" <schuetzm at gmx.net> wrote:
> 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.

Hm I interpreted it the other way round, it's wasteful to spend time for
such optimizations, just.
But my english is probably not as good as yours.

Tobi