Superman has undergone many major continuity revamps prior to Man of Steel in '86, but those stories didn't throw away the previous history as explicitly as Byrne was asked to do by DC. The revamps done in the late 1940s and again in the late 1950s were very much throwing away the continuity established by previous stories, particularly in regard to the details of Krypton and Clark's childhood.
I expect Bendis's revamp will be similar to those earlier continuity revamps in that he'll certainly be giving new takes on old events that may not jibe with whatever was in continuity Pre-Crisis, Post-Crisis, Pre-Flashpoint or whatever else. Bendis will be laying the foundation for whatever follows and Superman Reborn gave him the perfect vague overview of Superman's history from which he can pick and choose to use whatever he wants to emphasize or ignore.
All we really know about the current Superman is that he seems to be a combination of the Pre-Flashpoint Superman, who himself was a combination of Pre-Crisis and Post-Crisis elements, with the broad strokes of the New 52 Superman's stories.