// not be a predecessor.
//
// Note that mergePredecessors behaves slightly differently between
// first and subsequent calls for a block.  For the first call, the
// starting state is approximated by taking the state from the
// predecessor whose state is smallest, and removing any elements not
// in all the other predecessors; this makes the smallest number of

        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;
        } else if (pred != null) { // We are unlinking this node and it has a predecessor.
          pred.next = succ;
          if (pred.thread == null) { // We raced with another node that unlinked pred. Restart.
            continue restart;
          }

        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;
        } else if (pred != null) { // We are unlinking this node and it has a predecessor.
          pred.next = succ;
          if (pred.thread == null) { // We raced with another node that unlinked pred. Restart.
            continue restart;
          }

					if !m.Type.IsMemory() {
						break
					}
					memPreds[m] = true
					if len(m.Args) == 0 {
						break
					}
					m = m.MemoryArg()
				}
			}

			// We can merge if v is a predecessor of mem.
			//
			// For example, we can merge load into target in the
			// following scenario:
			//      x = read ... v
			//    mem = write ... v
			//   load = read ... mem
			// target = add x load

	}
	unlock(&span.speciallock)
	releasem(mp)
	return result
}

// Find a splice point in the sorted list and check for an already existing
// record. Returns a pointer to the next-reference in the list predecessor.
// Returns true, if the referenced item is an exact match.
func (span *mspan) specialFindSplicePoint(offset uintptr, kind byte) (**special, bool) {
	// Find splice point, check for existing record.