[llvm] LoopVectorize ptr init (PR #139807)

[Florian Hahn via llvm-commits]

https://github.com/fhahn approved this pull request.

LGTM, thanks.

@gchaltas do you need help merging the PR? 

Would be good to adjust the title to be a bit more descriptive, maybe something like `[LV] Initialize IR block pointers in ILV. (NFC)`

https://github.com/llvm/llvm-project/pull/139807