Need a Faster Compressor

[Timon Gehr via Digitalmars-d]

On 21.05.2016 23:12, Walter Bright wrote:
> The current one is effective, but slow:
>
>    https://github.com/dlang/dmd/blob/master/src/backend/compress.c
>
> Anyone want to make a stab at making it faster? Changing the format is
> fair game, as well as down and dirty assembler if that's what it takes.
>
> So really, how good are you at fast code?

Why is longest_match Ω(nm) instead of O(n+m) (e.g. KMP)?