--rerere-autoupdate--no-rerere-autoupdate-
After the rerere mechanism reuses a recorded resolution on the current conflict to update the files in the working tree, allow it to also update the index with the result of resolution.
--no-rerere-autoupdateis a good way to double-check what linkgit:git-rerere[1] did and catch potential mismerges, before committing the result to the index with a separate linkgit:git-add[1].