[llvm] [IndVarSimplify] Relax Restrictions on Loop Counter Stride (PR #146992)

[via llvm-commits]

buggfg wrote:

Hi @preames, this PR relaxes the stride restriction for LoopCounter to 1 or -1, providing an opportunity to rewrite the loop exit condition for common countdown loop structures.  As an external contributor, I am unable to assign reviewers directly. Would you be willing to review this change when you have the chance? Many thanks in advance :)

https://github.com/llvm/llvm-project/pull/146992