[llvm] [LV] Add support for cmp reductions with decreasing IVs. (PR #140451)

[Ramkumar Ramachandra via llvm-commits]

================
@@ -1324,8 +1327,8 @@ Value *llvm::createSimpleReduction(IRBuilderBase &Builder, Value *Src,
 Value *llvm::createSimpleReduction(IRBuilderBase &Builder, Value *Src,
                                    RecurKind Kind, Value *Mask, Value *EVL) {
   assert(!RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind) &&
-         !RecurrenceDescriptor::isFindLastIVRecurrenceKind(Kind) &&
-         "AnyOf or FindLastIV reductions are not supported.");
+         !RecurrenceDescriptor::isFindIVRecurrenceKind(Kind) &&
+         "AnyOf, FindFirstIV and FindLastIV reductions are not supported.");
----------------
artagnon wrote:

```suggestion
         "AnyOf and FindIV reductions are not supported.");
```

https://github.com/llvm/llvm-project/pull/140451