message: [XLA] [NFC] Add some missing logging lines to buffer assignment
diff: @@ -821,12 +821,18 @@ bool BufferAssigner::LiveRangeInterferes(const HloValue* buffer1,
  auto operand_value = buffer1;
  auto user_value = buffer2;
  if (!can_share_as_operand(user_value, operand_value)) {
  + VLOG(4) << "End of live range of " << buffer1->ToShortString()
  + << " is equal to the start of live range of "
  + << buffer2->ToShortString() << ", buffer cannot be shared.";
  return true;
  }
  } else if (live_range_2.end == live_range_1.start) {
  auto operand_value = buffer2;
  auto user_value = buffer1;
  if (!can_share_as_operand(user_value, operand_value)) {
  + VLOG(4) << "End of live range of " << buffer2->ToShortString()
  + << " is equal to the start of live range of "
  + << buffer1->ToShortString() << ", buffer cannot be shared.";
  return true;
  }
  } else {
  @@ -911,6 +917,9 @@ bool BufferAssigner::MaybeAssignBuffer(BufferAllocation* allocation,
  for (const HloValue* new_value : hlo_buffer.values()) {
  if (assignment->hlo_live_range().total_order_scheduled()) {
  if (LiveRangeInterferes(new_value, &assigned_buffer, assignment)) {
  + VLOG(4) << "Can't assign: assignee " << assigned_buffer
  + << " live range interferes with "
  + << new_value->ToShortString();
  return false;
  }
  } else if (assignment->hlo_ordering().MayInterfere(
  