message: Implement rotate_{left,right} intrinsics
diff: @@ -281,6 +281,16 @@ pub fn codegen_intrinsic_call<'a, 'tcx: 'a>(
  };
  ret.write_cvalue(fx, res);
  };
  + rotate_left, <T>(v x, v y) {
  + let layout = fx.layout_of(T);
  + let res = fx.bcx.ins().rotl(x, y);
  + ret.write_cvalue(fx, CValue::ByVal(res, layout));
  + };
  + rotate_right, <T>(v x, v y) {
  + let layout = fx.layout_of(T);
  + let res = fx.bcx.ins().rotr(x, y);
  + ret.write_cvalue(fx, CValue::ByVal(res, layout));
  + };
  offset, (v base, v offset) {
  let res = fx.bcx.ins().iadd(base, offset);
  ret.write_cvalue(fx, CValue::ByVal(res, args[0].layout()));
  