[llvm] [MemCpyOpt] Merge alias metadatas when replacing arguments (PR #67539)

[Nikita Popov via llvm-commits]

nikic wrote:

Here's a simple example for the memcpyopt+dse combination: https://llvm.godbolt.org/z/EnbPsqab1

https://github.com/llvm/llvm-project/pull/67539