[llvm] [MemCpyOpt] Drop dead `memmove` calls on `memset`'d source data (PR #101930)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Is there any real-world code written like this?

See https://github.com/dtcxzyw/llvm-opt-benchmark/pull/1135/files


https://github.com/llvm/llvm-project/pull/101930