dmd codegen improvements

[via Digitalmars-d]

On Wednesday, 19 August 2015 at 10:50:24 UTC, Ola Fosheim Grøstad 
wrote:
> Well… I can't argue with what you find interesting. Memory 
> throughput and pipeline bubbles are the key bottlenecks these 
> days.

And just to stress this point: if you code is spending 50% of the 
time waiting for memory and your code is 25% slower than the 
competitor, then it might actually be 50% slower than the 
competitor for code that is memory optimal.

So it's not like you just have to make your code a little bit 
faster, you have to make it twice as fast.

The only way to go past that is to have a very intelligent 
optimizer that can remove memory bottle necks and then you need 
the much more advanced cache/SIMD-oriented optimizer and probably 
also change the language semantics so that memory layout can be 
reordered.