Query the alignment of a specific variable

C++11 introduced the alignas specifier to specify the alignment of a variable, and the alignof operator to query the default alignment of a type. However, I don't see any way to get the alignment of a specific variable. Let's take the following trivial example:

alignas(16) float* array;

Here is what we can do about it:

• alignof(float*) returns 8, which is obviously not what we want.
• alignof(array) returns 16, which is exactly what we want, but that's a compiler extension; alignof as specified by the standard can't be used on a specific variable.
• alignof(decltype(array)) returns 8, which was quite expected but not what we want.
• std::alignment_of is implemented in terms of alignof, so it doesn't help much.

I would like a mechanism to confirm that the specific variable array is aligned on a 16 byte boundary. Is there anything in the standard to perform such a query?