Save scumming is possible by changing the name(N, "this ugly creature already has a name") of your character, the autosave will then rename the save file accordingly!
When you die your current character and save will be lost and you can't immediately reload your character but if you close the ADOM program and restart it, the previous "character name" .autosave has been reloaded and you can continue from where you changed the name of your character.

This happens at least on OSx prerelease 60 ASCII version