Proposed resolution:

This wording is relative to N5008.

1. Modify [ptr.align] as indicated:

   template<size_t Alignment, class T>
     bool is_sufficiently_aligned(T* ptr);
   

   -?- Mandates:

   1. (?.1) — `Alignment` is a power of two, and

   2. (?.2) — Alignment >= alignof(T) is `true`.

   -10- Preconditions: `p` points to an object `X` of a type similar ([conv.qual]) to `T`.

   -11- Returns: `true` if `X` has alignment at least `Alignment`, otherwise `false`.

   -12- Throws: Nothing.

`is_sufficiently_aligned` should mandate that the alignment template argument is a power of two and that it is greater equal to the byte alignment of its type template argument.

In [ptr.align] `is_sufficiently_aligned` has no Mandates element. It is an oversight that we realized when implementing P2897R7 into libc++ (in https://github.com/llvm/llvm-project/pull/122603). The function template was originally proposed as a static member function of the `aligned_accessor` class template which has these two Mandates clauses and therefore applied (see [mdspan.accessor.aligned.overview] p1). It revision P2897R4, `is_sufficiently_aligned` was moved out the class template definition to become the free function memory helper that was voted into C++26 but the Mandates were lost in the process.

We propose to correct that oversight and reintroduce the following Mandates clauses right above [ptr.align] p10.