When generating a switch for:

  case e of
    0 -> A
    1 -> B

instead of generating

  if (e < 1) then goto A
  B

generate

  if (e >= 1) then goto B
  A

because this helps the NCG to generate better code.  In particular, if
e is a comparison, then we don't need to reverse the sense of the
comparison to eliminate the comparse against 1 (the NCG does try to
reverse the comparison, but floating-point comparisons can't be
reversed).