Function floor_log2

tensorflow/lite/experimental/ruy/size_util.h:27–36

namespace ruy {

inline int floor_log2(int n) {
  RUY_DCHECK_GE(n, 1);
#ifdef _WIN32
  unsigned long result;  // NOLINT[runtime/int]
  _BitScanReverse(&result, n);
  return result;
#else
  return 31 - __builtin_clz(n);
#endif
}

inline int ceil_log2(int n) {
  RUY_DCHECK_GE(n, 1);