[clang] [clang] Generate appropriate assume in presence of libc's memcpy (PR #119704)

[Nikita Popov via cfe-commits]

https://github.com/nikic requested changes to this pull request.

This is no longer the case after [N3322](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3322.pdf).

(Incidentally, I wrote a blog post about this yesterday: https://developers.redhat.com/articles/2024/12/11/making-memcpynull-null-0-well-defined)

https://github.com/llvm/llvm-project/pull/119704