On: Popcount CPU instruction (2019)

[jagrsw]

Hamming distance (and popcnt) is also used in gradient descent scenarios.

Eg. here's part of fuzzing engine code, where it tries to produce an input which matches some form of variable check inside the fuzzed code:

https://github.com/google/honggfuzz/blob/1f09e3bfb0785d9b311...

  register uint8_t v = ((sizeof(Arg1) * 8) - __builtin_popcount(Arg1 ^ Arg2));
  uint8_t prev = ATOMIC_GET(globalCovFeedback->bbMapCmp[pos]);
    if (prev < v) {
    ...