[clang] -fsanitize=alignment: check memcpy/memmove arguments (PR #67766)

[Nikita Popov via cfe-commits]

nikic wrote:

Uh, why are we allowed to assume that memcpy pointer arguments are aligned? This looks like a miscompile to me.

A plain `int *` pointer is not required to be aligned, and memcpy works on `void *` pointers, so I'm not sure where an alignment requirement would appear from.

https://github.com/llvm/llvm-project/pull/67766