[llvm] [LowerMemIntrinsics] Lower llvm.memmove to wide memory accesses (PR #100122)

[Fabian Ritter via llvm-commits]

ritter-x2a wrote:

> Do we have unit tests executing memmove with the different overlap cases?

I didn't find any and when I break the implementation by emitting memcpy instead, only the three regression tests that I adjusted for this PR fail (including the test-suite), so: no.
I wrote memmove tests in HIP for testing this patch; I'm considering putting them into [the HIP part of the test-suite](https://github.com/llvm/llvm-test-suite/tree/main/External/HIP), so that they are actually executed. Is there a better way to add tests for the functional correctness of the memmove lowering?

https://github.com/llvm/llvm-project/pull/100122