[llvm] LSV: forbid load-cycles when vectorizing; fix bug (PR #104815)

[Björn Pettersson via llvm-commits]

bjope wrote:

I suggest adding at least one of the extra reproducers from the comment here: https://github.com/llvm/llvm-project/issues/37865#issuecomment-981000940

IIRC the earlier proposed fix in https://reviews.llvm.org/D54468 wasn't considered as valid since it only solved the simpler test case impacted by this patch, while not solving those extra reproducers. It would be nice to see that this solution is more complete, also fixing some of the other reproducers.

https://github.com/llvm/llvm-project/pull/104815