[llvm] [LV] Support argmin/argmax with strict predicates. (PR #170223)

[via llvm-commits]

================
@@ -166,9 +168,11 @@ struct VPlanTransforms {
                                         const TargetLibraryInfo &TLI);
 
   /// Try to legalize reductions with multiple in-loop uses. Currently only
-  /// min/max reductions used by FindLastIV reductions are supported. Otherwise
-  /// return false.
-  static bool handleMultiUseReductions(VPlan &Plan);
+  /// min/max reductions used by FindLastIV and FindFirstIV reductions are
+  /// supported. Otherwise return false.
----------------
ayalz wrote:

```suggestion
  /// strict and non-strict min/max reductions used by FindLastIV reductions are
  /// supported, corresponding to computing the first and last argmin/argmax,
  /// respectively. Otherwise return false.
```

https://github.com/llvm/llvm-project/pull/170223