[llvm] [ValueTracking] isNonEqual Pointers with with a recursive GEP (PR #70459)

[David Sherwood via llvm-commits]

================
@@ -3141,6 +3141,63 @@ static bool isNonEqualSelect(const Value *V1, const Value *V2, unsigned Depth,
          isKnownNonEqual(SI1->getFalseValue(), V2, Depth + 1, Q);
 }
 
+static bool isNonEqualPointersWithRecursiveGEP(const Value *A, const Value *B,
+                                               unsigned Depth,
+                                               const SimplifyQuery &Q) {
+  // Where A is a recursive GEP for an incoming value of PHI indicating a
----------------
david-arm wrote:

Perhaps worth moving some of these comments above the function to give an overall description of what it's doing and what the arguments mean? i.e. something like

```
\\ Check to see if A is both a GEP and is the incoming value for a PHI in the loop,
\\ and B is either a ptr or another GEP. If the PHI has 2 incoming values, one 
\\ of them being the recursive GEP A and the other a ptr at same base and at the
\\ same/higher offset than B we are only incrementing the pointer further in 
\\ loop if offset of recursive GEP is greater than 0.
```

https://github.com/llvm/llvm-project/pull/70459