[llvm] [SCEV] Extend isImpliedCondOperandsViaRanges to independent predicates (PR #71110)

[Philip Reames via llvm-commits]

preames wrote:

@nikic Can you take a second look at the test changes?  There's a couple which are worth comment.  When rebasing to eliminate the white space, I discovered I'd missed updating a couple originally.

test/Analysis/ScalarEvolution/trip-count-negative-stride.ll -- This looks mildly concerning on the surface, but I think it's safe to ignore.  The entire loop nest is immediate UB, and the inner loop expression simplifies to 7 /u 0.  (We're missing that simplification.)

test/CodeGen/BPF/loop-exit-cond.ll - I'm clearly breaking the intention of the test here.  However, looking at the commit that introduced this, the patch made a cost model change and asserted that disabled LFTR.  That was never true to begin with beyond one very narrow test case, so I don't feel bad effectively reverting that behavior.  I'm honestly tempted just to delete the test.

https://github.com/llvm/llvm-project/pull/71110