practicality of empirical cache optimization in D vs C++

[Kirill via Digitalmars-d-learn]

Dear D community (and specifically experts on cache optimization),

I'm a C++ programmer and was waiting for a while to do a project 
in D.

I'd like to build a cache-optimized decision tree forest library, 
and I'm debating between D and C++. I'd like to make it similar 
to atlas, spiral, or other libraries that partially use static 
optimization with recompilation and meta-programming to cache 
optimize the code for a specific architecture (specifically the 
latest xeons / xeon phi). Given D's compile speed and 
meta-programming, it should be a good fit. The problem that I 
might encounter is that C++ has a lot more information on the 
topic, which might be significant bottleneck given I'm just 
learning cache optimization (from a few papers and "what every 
programmer should know about memory").

 From my understanding, cache optimization mostly involves 
breaking data and loops into segments that fit in cache, and 
making sure that commonly used variables (for example sum in 
sum+=i) stay in cache. Most of this should be solved by 
statically defining sizes and paddings of blocks to be used for 
caching. It's more related to low level -- C, from my 
understanding. Are there any hidden stones?

The other question is how mature is the compiler in terms of 
optimizing for cache comparing to C++? I think gnu C++ does a few 
tricks to optimize for cache and there are ways to tweak cache 
line alignment.

My knowledge on the subject is not yet concrete and limited but I 
hope this gave an idea of what I'm looking for and you can 
recommend me a good direction to take.

Best regards,
--Kirill