Function Log2Floor64

tensorflow/core/lib/core/bits.h:42–44

Return floor(log2(n)) for positive integer n. Returns -1 iff n == 0.

// Return floor(log2(n)) for positive integer n.  Returns -1 iff n == 0.
inline int Log2Floor64(uint64 n) {
  return n == 0 ? -1 : 63 ^ __builtin_clzll(n);
}

#else