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

[Mel Chen via llvm-commits]

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@@ -712,6 +726,17 @@ RecurrenceDescriptor::isFindIVPattern(RecurKind Kind, Loop *TheLoop,
                                      m_Value(NonRdxPhi)))))
     return InstDesc(false, I);
 
+  if (isFindLastRecurrenceKind(Kind)) {
+    // Must be an integer scalar.
+    Type *Type = OrigPhi->getType();
+    if (!Type->isIntegerTy())
+      return InstDesc(false, I);
----------------
Mel-Chen wrote:

We can remove the type checking. `AddReductionVar` has already performed this check:
```
    Type *ScalarTy = RecurrenceType->getScalarType();
    if (ScalarTy->isFloatingPointTy()) {
      if (!isFloatingPointRecurrenceKind(Kind))
        return false;
    } else if (ScalarTy->isIntegerTy()) {
      if (!isIntegerRecurrenceKind(Kind))
        return false;
      if (!isMinMaxRecurrenceKind(Kind))
        Start = lookThroughAnd(Phi, RecurrenceType, VisitedInsts, CastInsts);
    } else {
      // Pointer min/max may exist, but it is not supported as a reduction op.
      return false;
    }
```

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