I've been wondering how much you'd pay if you just required that out of bounds accesses be a no-op with an option of calling an error handler. De-reference a null or out of bounds pointer you get zero. Write out of bounds, does nothing.

  int a = v[-100]; // yolo a is set to 0

I really suspect that unlike the RISC mental model compiler writers think in terms of a superscalar processor would barely be slowed down. That is if the compiler doesn't delete the checks because it can prove they aren't needed.