[llvm] [LoopInterchange] Prevent interchange if one index is constant and the other has loop carried dependence (PR #79123)

[via llvm-commits]

ShivaChen wrote:

> This doesn't look like the correct approach to me. A constant index should result in a scalar dependence, so there is no need to specify an output parameter to the `depends` interface.

It seems SIV test of the second index will dominate the direction results. I try to use another approach. That is using ZIV test to catch the scalar index and then compare SIV test result to catch the one scalar index and the other index has loop carried.
Does it sound reasonable?

https://github.com/llvm/llvm-project/pull/79123