[llvm] [ValueTracking] Handle recursive select/PHI in ComputeKnownBits/IsKnownNonZero (PR #114689)

[via llvm-commits]

================
@@ -1580,14 +1582,22 @@ static void computeKnownBitsFromOperator(const Operator *I,
                                                : SI->getTrueValue();
             IncDepth = Depth + 1;
           }
+        } else if (auto *IncPhi = dyn_cast<PHINode>(IncValue);
----------------
goldsteinn wrote:

Done, let me know if you want me to break it out to an NFC

https://github.com/llvm/llvm-project/pull/114689