// Adds operations to compute the partial derivatives of sum of `y`s w.r.t `x`s,
// i.e., d(y_1 + y_2 + ...)/dx_1, d(y_1 + y_2 + ...)/dx_2...
// This is a variant of TF_AddGradients that allows to caller to pass a custom
// name prefix to the operations added to a graph to compute the gradients.
//
// `dx` are used as initial gradients (which represent the symbolic partial

   * bits.
   *
   * @param h hash code
   */
  static int rehash(int h) {
    // Spread bits to regularize both segment and index locations,
    // using variant of single-word Wang/Jenkins hash.
    // TODO(kevinb): use Hashing/move this to Hashing?
    h += (h << 15) ^ 0xffffcd7d;
    h ^= h >>> 10;
    h += h << 3;
    h ^= h >>> 6;
    h += (h << 2) + (h << 14);

	VMOVQ X20, -15(R11)(CX*1) // 62c1fd087ea40bf1ffffff or 62c1fd08d6a40bf1ffffff
	VMOVQ X20, (SP)(AX*2)     // 62e1fd087e2444 or 62e1fd08d62444
	// VMOVHPD: overlapping VEX and EVEX variants.
	VMOVHPD (AX), X5, X5             // c5d11628 or c4e1d11628 or 62f1d5281628 or 62f1d5481628
	VMOVHPD 7(DX), X5, X5            // c5d1166a07 or 62f1d52816aa07000000 or 62f1d54816aa07000000

      Iterator<? extends T> iterator) {
    checkNotNull(iterator);
    if (iterator instanceof UnmodifiableIterator) {
      @SuppressWarnings("unchecked") // Since it's unmodifiable, the covariant cast is safe
      UnmodifiableIterator<T> result = (UnmodifiableIterator<T>) iterator;
      return result;
    }
    return new UnmodifiableIterator<T>() {
      @Override
      public boolean hasNext() {

  public static <V extends @Nullable Object> ListenableFuture<V> immediateFuture(
      @ParametricNullness V value) {
    if (value == null) {
      // This cast is safe because null is assignable to V for all V (i.e. it is bivariant)
      @SuppressWarnings("unchecked")
      ListenableFuture<V> typedNull = (ListenableFuture<V>) ImmediateFuture.NULL;
      return typedNull;
    }
    return new ImmediateFuture<>(value);
  }

  /**