[llvm] ADT/Matrix: two-dimensional Container with View (PR #98893)

[Jakub Kuderski via llvm-commits]

kuhar wrote:

> Besides, std::mdspan is only available from C++26

My point was that we could implement something like mdspan in LLVM.

> This is related to adding constexpr to ArrayRef, because otherwise, I can't mark anything that depends on ArrayRef functions as constexpr.

What are constexpr functions do you need that depend on ArrayRef? 



https://github.com/llvm/llvm-project/pull/98893