message: Fix transmute of non-scalar to scalar
  Fixes
diff: @@ -123,7 +123,7 @@ pub(crate) fn load_scalar(self, fx: &mut FunctionCx<'_, 'tcx, impl Backend>) ->
  scalar_to_clif_type(fx.tcx, element.clone())
  .by(u16::try_from(count).unwrap()).unwrap()
  }
  - _ => unreachable!(),
  + _ => unreachable!("{:?}", layout.ty),
  };
  ptr.load(fx, clif_ty, MemFlags::new())
  }
  @@ -458,7 +458,7 @@ fn write_cvalue_maybe_transmute(
  let dst_layout = self.layout();
  let to_ptr = match self.inner {
  CPlaceInner::Var(var) => {
  - let data = from.load_scalar(fx);
  + let data = CValue(from.0, dst_layout).load_scalar(fx);
  let src_ty = fx.bcx.func.dfg.value_type(data);
  let dst_ty = fx.clif_type(self.layout().ty).unwrap();
  let data = match (src_ty, dst_ty) {
  @@ -487,7 +487,7 @@ fn write_cvalue_maybe_transmute(
  CPlaceInner::Addr(_, Some(_)) => bug!("Can't write value to unsized place {:?}", self),
  };
  - match self.layout().abi {
  + match from.layout().abi {
  // FIXME make Abi::Vector work too
  Abi::Scalar(_) => {
  let val = from.load_scalar(fx);
  