I have asked this question in the past and was told that memcpy() is allowed to preemptively read before it has determined it needs to write to make it faster o

I have asked this question in the past and was told that memcpy() is allowed to preemptively read before it has determined it needs to write to make it faster on some CPUs. The presumption is that if you are going to be copying data, there is at least one cache line there already, so reading can start early.