4 ms·

Have you considered arr[max(i, arr.len)] instead of AND?

• tetromino_ 9y ago
  Max() is not a CPU instruction. It's an abstraction, a function that could be implemented either using a branch (which defeats the whole purpose) or, on some architectures, with something like cmovXX. Perhaps they wanted a solution that works on Arm, which I think doesn't have cmovXX. Or maybe Intel does speculation with cmovXX used on array index.
  • olliej 9y ago
    Cmov can speculate as well (it makes sense from a performance standpoint but that isn’t the same as secure ;) )
    • om2 9y ago
      On some CPUs, cmov is known not to speculate, but in those cases it is apparently super slow.