final Object nextVmt;
final Address nextObjectPtr = start.add(nextOffset);
nextVmt = nextObjectPtr.loadObjectReference(tibOffset);
if (nextVmt == FREE) {
// Combine two free spaces
Word nextObjSize = nextObjectPtr.loadWord(sizeOffset);
Word newObjSize = objSize.add(headerSize).add(nextObjSize);
ptr.store(newObjSize, sizeOffset);
// Do not increment offset here, because there may be
// another next free object, which we will combine
// in the next loop.