[llvm] [DSE] Fold malloc/store pair into calloc (PR #87048)

[via llvm-commits]

XChy wrote:

> Should we revert the transform when the memory region allocated by calloc will be overridden by other stores?

Sounds reasonable. `calloc` can be modelled as a `malloc` and a following `memset`/`store`, so I guess we can eliminate the virtual `memset`/`store` as DSE has done for real memorydef. But I'm not that familiar with the code of DSE. @fhahn, could you provide any insight?

https://github.com/llvm/llvm-project/pull/87048