[llvm] [VPlan] Introduce ComputeReductionResult VPInstruction opcode. (PR #70253)

[via llvm-commits]

================
@@ -3513,11 +3501,6 @@ void InnerLoopVectorizer::fixCrossIterationPHIs(VPTransformState &State) {
   VPBasicBlock *Header =
       State.Plan->getVectorLoopRegion()->getEntryBasicBlock();
 
-  for (VPRecipeBase &R : Header->phis()) {
-    if (auto *ReductionPhi = dyn_cast<VPReductionPHIRecipe>(&R))
-      fixReduction(ReductionPhi, State);
----------------
ayalz wrote:

So now better rename fixCrossIterationPHIs() to fixFixedOrderRecurrences(), along with an explanation that inductions and reductions are fixed by VPlan execute? Or leave a TODO for now, until FORs are also fixed by VPlan and this method can be retired.

https://github.com/llvm/llvm-project/pull/70253