Perlin noise benchmark speed

[Nick Treleaven via Digitalmars-d]

Hi,
A Perlin noise benchmark was quoted in this reddit thread:

http://www.reddit.com/r/rust/comments/289enx/c0de517e_where_is_my_c_replacement/cibn6sr

It apparently shows the 3 main D compilers producing slower code than 
Go, Rust, gcc, clang, Nimrod:

https://github.com/nsf/pnoise#readme

I initially wondered about std.random, but got this response:

"Yeah, but std.random is not used in that benchmark, it just initializes 
256 random vectors and permutates 256 sequential integers. What spins in 
a loop is just plain FP math and array read/writes. I'm sure it can be 
done faster, maybe D compilers are bad at automatic inlining or something. "

Obviously this is only one person's benchmark, but I wondered if people 
would like to check their code and suggest reasons for the speed deficit.