[SYCL] Forbid non-trivially-copyable type in annotated_ptr/ref class

[broxigarchen]

1. Explicitly state that use non-trivially-copyable type in annotated_ptr and annotated_ref is not supported and error out if annotated_ptr is constructed with non-trivially-copyable type

2. void is allowed on annotated_ptr as an exception

3. Use pass-by-value in annotated_ref operator= now, and updated the spec
   this fix volatile type not supported in the following code

void func(const T& a) { ... }
volatile T b;
func(b); // this will error out

[gmlueck]

I assume we would to the same thing here [compound assignment]

Not just that. We should do this consistently for all arguments taking const T&

Yes, I agree. However, I think the only other place there is an argument of type const T& is in the compound assignment operators.

annotated_ref doesn't own the data (like e.g. span or ptr). The assignment changes the data not what we refer to. Therefore it is correct to assign to a const annotated_ref (which is allowed by it not being const)

In this case, shouldn't we add const to all these operators for consistency?

 T operator++();
 T operator++(int);
 T operator--();
 T operator--(int);

It seems inconsistent that aptr[0] += 1 works for a const aptr but aptr[0]++ does not.

[rolandschulz]

Yes, I agree. However, I think the only other place there is an argument of type const T& is in the compound assignment operators.

You're right.

In this case, shouldn't we add const to all these operators for consistency?

Yes. That's a bug introduced when we added those.

[steffenlarsen]

Runtime changes LGTM. I'll let the other's approve the extensions changes.

[broxigarchen]

@intel/llvm-gatekeepers Hi can you please help to merge this? Thanks!

The CI error seems not related

[aelovikov-intel]

Failed Tests (1):
  SYCL :: Regression/vec_rel_swizzle_ops.cpp

is already under investigation as per #12029 (comment).

I think I've seen some discussion about

Timed Out Tests (1):
  SYCL :: Basic/vector/int-convert.cpp

as well.