Old problem with performance

[naryl]

It's a bit offtopic but I'd be grateful if someone can explain why D with structs completes this simple benchmark (see attachment) so slowly compared to C++ with classes on stack:

D struct - 27.85s 
C++ stack - 8.32s

D class - 271.58s
C++ heap - 249.32s

Compiled with "dmd -O". -release decreases performance by 10% in this case. -inline doesn't affects it at all.
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