const int peak_loc) const {
  SizeT max_savings = 0;

  // We're looking at the outputs of all operators in [`begin`, `end`).  If an
  // output is alive after `peak_loc`, rematerializing the operator anywhere
  // after `peak_loc` would lower the memory profile at `peak_loc`.
  for (int ioperation = begin; ioperation != end; ++ioperation) {

  // [begin, end) after operation `peak_location`
  SizeT MaxSavings(int begin, int end, int peak_loc) const;

  // If I want to remat ops [begin, end) after the op at operation `peak_loc`,
  // find the latest point at which to reinsert them (the op before which to
  // insert.)
  int FindBestRematPoint(int begin, int end, int peak_loc) const;

  // The memory objects.
  struct Tensor {