[llvm] [LV] Vectorize conditional scalar assignments (PR #158088)

[Benjamin Maxwell via llvm-commits]

================
@@ -175,13 +178,12 @@ class RecurrenceDescriptor {
   /// Returns a struct describing whether the instruction is either a
   ///   Select(ICmp(A, B), X, Y), or
   ///   Select(FCmp(A, B), X, Y)
-  /// where one of (X, Y) is an increasing (FindLast) or decreasing (FindFirst)
-  /// loop induction variable, and the other is a PHI value.
-  // TODO: Support non-monotonic variable. FindLast does not need be restricted
-  // to increasing loop induction variables.
-  LLVM_ABI static InstDesc isFindIVPattern(RecurKind Kind, Loop *TheLoop,
-                                           PHINode *OrigPhi, Instruction *I,
-                                           ScalarEvolution &SE);
+  /// where one of (X, Y) is an increasing (FindLastIV) or decreasing
+  /// (FindFirstIV) loop induction variable or an (FindLast) arbitrary integer
+  /// value, and the other is a PHI value.
----------------
MacDue wrote:

```suggestion
  /// (FindFirstIV) loop induction variable, or an arbitrary integer
  /// value (FindLast), and the other is a PHI value.
```

https://github.com/llvm/llvm-project/pull/158088