"no, no, it came by itself." You're being sarcastic, right? Of course CC don't sound like either of those bands, but anyone will tell you that DM evolved from Thrash. If you cannot hear clear examples of this in songs like "A Skull Full of Maggots", then you must not know what Thrash (particularly post-Reign In Blood Thrash), really sounds like.
Maybe Cannibal Corpse guys were influenced by Dark Angel and Sadus - among other bands - (I wouldn't be surprised to learn they were), but no, I think you were tripping when you MISTAKENLY noticed that Cannibal Corpse came out of the mix between Sadus and Dark Angel.
You can't have Death Metal band from a Thrash band, after all, Death Metal just appeared, out of nowhere. It really didn't come from thrash metal, with a extra dose of aggression, no, no, it came by itself. :)