[llvm] [HashRecognize] Rewrite arePHIsIntertwined (PR #144878)

[Piotr Fusik via llvm-commits]

================
@@ -497,42 +497,46 @@ CRCTable HashRecognize::genSarwateTable(const APInt &GenPoly,
   return Table;
 }
 
-/// Checks if \p Reference is reachable from \p Needle on the use-def chain, and
-/// that there are no stray PHI nodes while digging the use-def chain. \p
-/// BOToMatch is a CRC peculiarity: at least one of the Users of Needle needs to
-/// match this OpCode, which is XOR for CRC.
-static bool arePHIsIntertwined(
-    const PHINode *Needle, const PHINode *Reference, const Loop &L,
-    Instruction::BinaryOps BOToMatch = Instruction::BinaryOpsEnd) {
-  // Initialize the worklist with Users of the Needle.
-  SmallVector<const Instruction *> Worklist;
-  for (const User *U : Needle->users()) {
-    if (auto *UI = dyn_cast<Instruction>(U))
-      if (L.contains(UI))
-        Worklist.push_back(UI);
-  }
+/// Checks that \p L and \p R are used together in an XOR in the use-def chain
----------------
pfusik wrote:

```suggestion
/// Checks that \p P1 and \p P2 are used together in an XOR in the use-def chain
```
and in the IR snippet comment.

https://github.com/llvm/llvm-project/pull/144878