Fastest way to move simple data types in array to specific positions

Question

What is the fastest way to move simple data types in array of known size to specific positions?

The specific case I had was rotating a game board stored as an int[9]
[0,1,2,3,4,5,6,7,8] becomes [6,3,0,7,4,1,8,5,2]

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In my use case I had a vector of these arrays, which each needed rotating.

Board Layout:

board1|corners|centers
0 1 2 | 0   2 |   1  
3 4 5 |       | 3   5
6 7 8 | 6   8 |   7

board2|corners|centers
6 3 0 | 6   0 |   3
7 4 1 |       | 7   1
8 5 2 | 8   2 |   5

The fastest method I came up with was to create a public variable to assign the array entries to, and then copy the memory back.

int layout[9];
int pub_layout[9];

#include <cstring> // for std::memcpy
void rotate(int layout[])
{
    pub_layout[4] = layout[4]; // center

    pub_layout[0] = layout[6]; // corner four
    pub_layout[6] = layout[8];
    pub_layout[8] = layout[2];
    pub_layout[2] = layout[0];

    pub_layout[1] = layout[3]; // center four
    pub_layout[3] = layout[7];
    pub_layout[7] = layout[5];
    pub_layout[5] = layout[1];

    std::memcpy(layout,pub_layout,sizeof(pub_layout));
}

I have seen a similar question here, which recommends
int[] b = new int[] {b[6], b[3], b[0], b[7], b[4], b[1], b[8], b[5], b[2]};
..though it clocks much slower (less than half the speed on a single thread)

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Both are relatively fast (see a test here)

If this is not the fastest method, what is?
I suspect the algorithm will be the same in both C and C++.

Answer 1

With this one you gain the memcpy call and the [4] to [4] assignment. You lose two assignments to the putAside variable. So it is surely a little bit faster.

int layout[9];
int putAside;

void rotate(int[] layout)
{
    putAside = layout[0];
    layout[0] = layout[6]; // corner four
    layout[6] = layout[8];
    layout[8] = layout[2];
    layout[2] = putAside;

    putAside = layout[1];
    layout[1] = layout[3]; // center four
    layout[3] = layout[7];
    layout[7] = layout[5];
    layout[5] = putAside;
}