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

[Florian Hahn via llvm-commits]

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@@ -3643,169 +3614,6 @@ void InnerLoopVectorizer::fixFixedOrderRecurrence(
   Phi->setName("scalar.recur");
 }
 
-void InnerLoopVectorizer::fixReduction(VPReductionPHIRecipe *PhiR,
-                                       VPTransformState &State) {
-  PHINode *OrigPhi = cast<PHINode>(PhiR->getUnderlyingValue());
-  // Get it's reduction variable descriptor.
-  assert(Legal->isReductionVariable(OrigPhi) &&
-         "Unable to find the reduction variable");
-  const RecurrenceDescriptor &RdxDesc = PhiR->getRecurrenceDescriptor();
-
-  RecurKind RK = RdxDesc.getRecurrenceKind();
-  TrackingVH<Value> ReductionStartValue = RdxDesc.getRecurrenceStartValue();
-  Instruction *LoopExitInst = RdxDesc.getLoopExitInstr();
-  if (auto *I = dyn_cast<Instruction>(&*ReductionStartValue))
-    State.setDebugLocFrom(I->getDebugLoc());
-
-  VPValue *LoopExitInstDef = PhiR->getBackedgeValue();
-
-  // Before each round, move the insertion point right between
-  // the PHIs and the values we are going to write.
-  // This allows us to write both PHINodes and the extractelement
-  // instructions.
-  Builder.SetInsertPoint(LoopMiddleBlock,
-                         LoopMiddleBlock->getFirstInsertionPt());
-
-  State.setDebugLocFrom(LoopExitInst->getDebugLoc());
-
-  Type *PhiTy = OrigPhi->getType();
-  // If tail is folded by masking, the vector value to leave the loop should be
-  // a Select choosing between the vectorized LoopExitInst and vectorized Phi,
-  // instead of the former. For an inloop reduction the reduction will already
-  // be predicated, and does not need to be handled here.
-  if (Cost->foldTailByMasking() && !PhiR->isInLoop()) {
-    VPValue *Def = nullptr;
-    for (VPUser *U : LoopExitInstDef->users()) {
-      auto *S = dyn_cast<VPInstruction>(U);
-      if (S && S->getOpcode() == Instruction::Select) {
-        Def = S;
-        break;
-      }
-    }
-    if (Def)
-      LoopExitInstDef = Def;
-  }
-
-  VectorParts RdxParts(UF);
-  for (unsigned Part = 0; Part < UF; ++Part)
-    RdxParts[Part] = State.get(LoopExitInstDef, Part);
-
-  // If the vector reduction can be performed in a smaller type, we truncate
-  // then extend the loop exit value to enable InstCombine to evaluate the
-  // entire expression in the smaller type.
-  if (VF.isVector() && PhiTy != RdxDesc.getRecurrenceType()) {
-    Builder.SetInsertPoint(LoopMiddleBlock,
-                           LoopMiddleBlock->getFirstInsertionPt());
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fhahn wrote:

Yep, should be cleaned-up with this refactoring

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