message: [XLA] Update cross-program-prefetch heuristic to break tie between equal-sized candidates.
  In case of tie, prefer a buffer whose consumer instructions produces larger buffer.
diff: @@ -114,6 +114,19 @@ FindCrossProgramPrefetchCandidate(
  // worse choices than just picking the largest buffer.
  // TODO(b/152421603): Investigate.
  auto size_compare = [](const auto& x, const auto& y) {
  + if (x.size == y.size) {
  + // When both buffers are of same size, we prefer the one that is used to
  + // produce larger tensors in its consumer instructions.
  + auto get_use_size =
  + [](const MemorySpaceAssignment::BufferInterval& bi) -> int64 {
  + int64 use_size = 0;
  + for (const auto& use : bi.buffer->uses()) {
  + use_size += ShapeUtil::ElementsInRecursive(use.instruction->shape());
  + }
  + return use_size;
  + };
  + return get_use_size(x) < get_use_size(y);
  + }
  return x.size < y.size;
  };
  auto& compare = options.default_cross_program_prefetch_heuristic &&
  