Transpose and interchange rows or columns (depends whether you want to rotate left or right).
e. g.
1) original matrix
1 2 3
4 5 6
7 8 9
2) transpose
1 4 7
2 5 8
3 6 9
3-a) change rows to rotate left
3 6 9
2 5 8
1 4 7
3-b) or change columns to rotate right
7 4 1
8 5 2
9 6 3
All these operations can be done without allocating memory.