A processing system limits the propagation of unnecessary memory updates by bypassing writing back dirty cache lines to other levels of a memory hierarchy in response to receiving an indication from software executing at a processor of the processing system that the value of the dirty cache line is dead (i.e., will not be read again or will not be read until after it has been overwritten). In response to receiving an indication from software that data is dead, a cache controller prevents propagation of the dead data to other levels of memory in response to eviction of the dead data or flushing of the cache at which the dead data is stored.