Pure, Nothrow in Generic Programming

[bearophile]

dsimcha:
> Isn't overflowing a signed int undefined behavior?

Yes, it can be.


>If so, how would we eliminate undefined behavior without very expensive runtime checks?<

I have explained LLVM devs how to speed-up some of those runtime checks.

Do you exactly know how much expensive they are, in synthetic benchmarks or real programs? (I have done few tests in dotnet C#, that has a switch to activate those runtime tests, results are not conclusive).

Do you prefer a less buggy program or a fast&buggy program?

There are ways to infer and remove at compile time part of those tests (or sometimes pull them out of loops).

Bye,
bearophile