[llvm] [VPlan] Remove createReduction. NFCI (PR #131336)

[David Sherwood via llvm-commits]

================
@@ -1345,24 +1345,6 @@ Value *llvm::createSimpleReduction(VectorBuilder &VBuilder, Value *Src,
   return VBuilder.createSimpleReduction(Id, SrcTy, Ops);
 }
 
-Value *llvm::createReduction(IRBuilderBase &B,
-                             const RecurrenceDescriptor &Desc, Value *Src,
-                             PHINode *OrigPhi) {
-  // TODO: Support in-order reductions based on the recurrence descriptor.
-  // All ops in the reduction inherit fast-math-flags from the recurrence
-  // descriptor.
-  IRBuilderBase::FastMathFlagGuard FMFGuard(B);
-  B.setFastMathFlags(Desc.getFastMathFlags());
-
-  RecurKind RK = Desc.getRecurrenceKind();
-  if (RecurrenceDescriptor::isAnyOfRecurrenceKind(RK))
-    return createAnyOfReduction(B, Src, Desc, OrigPhi);
-  if (RecurrenceDescriptor::isFindLastIVRecurrenceKind(RK))
----------------
david-arm wrote:

It's probably a good idea to strengthen the assert in `createSimpleReduction` to include findlast types, i.e.

```
  assert(!RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind) &&
         !RecurrenceDescriptor::isFindLastIVRecurrenceKind(Kind) &&
         "AnyOf reduction is not supported.");
```


https://github.com/llvm/llvm-project/pull/131336