From a C++/JS benchmark

[bearophile]

Denis Shelomovskij:

> (tests from bearophile's message, C++ test is "skinning_test_no_simd.cpp").

For a more realistic test I suggest you to time the C++ version that uses the intrinsics too (only for float).


> Looks like a spiteful joke... In other words: WTF?! JavaScript is about 
> 10 times faster than D in floating point calculations!? Please, tell me 
> that I'm mistaken.

Languages aren't slow or fast, their implementations produce assembly that's more or less efficient.

A D1 version fit for LDC V1 with Tango:
http://codepad.org/ewDy31UH

Vertices (millions), Linux 32 bit:
  C++ no simd:  29.5
  D:            27.6

LDC based on DMD v1.057 and llvm 2.6, ldc -O3 -release -inline

G++ V4.3.3, -s -O3 -mfpmath=sse -ffast-math -msse3

It's a bit slower than the C++ version, but for most people that's an acceptable difference (and maybe porting the C++ code to D instead of the C# one and using a more modern LLVM you reduce that loss a bit).

Bye,
bearophile