cgOp (LBitCast from to) [x] = do
  nx <- unbox (FArith from) x
  nx' <- inst $ BitCast nx (ftyToTy (FArith to)) []
  box (FArith to) nx'
cgOp (LBitCast from to) [x] = do
  nx <- unbox (FArith from) x
  nx' <- inst $ BitCast nx (ftyToTy (FArith to)) []
  box (FArith to) nx'
cgOp (LBitCast from to) [x] = do
  nx <- unbox (FArith from) x
  nx' <- inst $ BitCast nx (ftyToTy (FArith to)) []
  box (FArith to) nx'