[llvm] [LoopIdiom] Fix a DL-related crash in optimizeCRCLoop (PR #161509)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> I compiled the code below, but found that Info.LHSAux is null.

LHSAux is the optional checksum data, which is sometimes part of CRC algorithms: in your example, this is absent. I would recommend looking at https://github.com/llvm/llvm-test-suite/tree/main/SingleSource/UnitTests/HashRecognize: in particular, see the difference between the "data" and "nodata" tests: all of them are optimized using HashRecognize, and "nodata" tests correspond to the case when LHSAux is null.

https://github.com/llvm/llvm-project/pull/161509