Andrei Alexandrescu wrote:
* Efficiency - D generates native code for floating point operations and has control over data layout and allocation. Speed of generated code is dependent on the compiler, and the reference compiler (dmd) does a poorer job at it than the gnu-based compiler (gdc) compiler.
I'd like to add to this. Right now I'm reworking some libraries to include Simd support using DMD on Linux 64bit. A simple benchmark between DMD and GCC of 2 million simd vector addition/subtractions actually runs faster with my DMD D code than the GCC C code. Only by ~0.8 ms, and that could be due to a difference between D's sdt.datetime.StopWatch() and C's time.h/clock(), but it's consistently faster none-the-less, which is impressive.
That said, it's also much easier to "accidentally slow that figure down significantly in DMD, whereas GCC usually always optimizes very well.
Also, and I'm not sure this isn't just me, but I ran a DMD (v2.057 T think) vector test (no simd) against Mono C# a few moths back where DMD got only ~10 ms improvement over C# (~79ms vs ~88ms). Now a similar test compiled with DMD 2.060 runs at ~22ms vs C#'s 80ms, so I believe there's been some definite optimization improvements in the internal DMD compiler over the last few version.
