I think I get why C++ thru C are all similar (all compile to similar assembly?), but I don't get why Go thru maybe Racket are all in what looks like a pretty narrow clump. Is there a common element there?
for (long i = 2; i <= rounds + 2; i++) {
x *= -1.0;
pi += x / (2.0 * i - 1.0);
}
rounds += 2u; // do this outside the loop
for (unsigned i=2u; i < rounds; ++i) // use ++i instead of i++
{
double x = -1.0 + 2.0 * (i & 0x1); // allows vectorization
pi += (x / (2u * i - 1u)); // double / unsigned = double
}
You see something similar in the other kings-of-speed languages. Zig? It's the C code ported directly to a different syntax. D? Exact same. Fortran 90? Slightly different, but still obviously written with compiler vectorization in mind.
(For what it's worth, the trunk version of Clang is able to auto-vectorize either version of the loop without help.)
The one exception is sort of an exception that proves the rule: it's marked "C# (SIMD)", and looks like a native compiler and not a managed one.
- run bytecode - very high level - GC memory
But not all have these traits. Not sure.