Recently i submitted a page for the game Diablo and i saw there is no Hack and Slash in the Subgenre list.
Many games are actually Hack and Slash in th LGDB, like:
Hack Slash Loot (http://www.lgdb.org/game/hack_slash_loot)
Heroes of Loot (http://www.lgdb.org/game/heroes_loot)
They all are in the Roguelike Subgenre, it's not really the same thing. Roguelike is turn-based gameplay when hack and Slash is realtime.