Slow performance compared to C++, ideas?

[Timon Gehr]

On 06/07/2013 09:22 AM, Walter Bright wrote:
> ...
> There are two obvious reasons why a feature would not have much buzz:
>
> 1. it works perfectly
> 2. it isn't being used
>
> Value Range Propagation is a pretty good example of (1). Sadly, I
> suspect -cov is (2).
>
> I'd be happy to be wrong about that.
>

You are certainly wrong about the value range propagation part. The 
transformers for the bitwise operators are not the best possible.

ubyte x = ((y&252)^2)+1;

The above term can be easily proven to fit into ubyte by just using an 
analysis of the ranges of its subterms, yet DMD rejects it.