!fixup address latest comments, thanks

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -8289,7 +8289,6 @@ VPRecipeBase *VPRecipeBuilder::tryToCreateWidenRecipe(VPSingleDefRecipe *R,
       // If the PHI is used by a partial reduction, set the scale factor.
       unsigned ScaleFactor =
           getScalingForReduction(RdxDesc.getLoopExitInstr()).value_or(1);
-
       PhiRecipe = new VPReductionPHIRecipe(
           Phi, RdxDesc, *StartV, CM.isInLoopReduction(Phi),
           CM.useOrderedReductions(RdxDesc), ScaleFactor);
@@ -9328,11 +9327,11 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
           RecipeBuilder.getScalingForReduction(RdxDesc.getLoopExitInstr())
               .value_or(1);
       Type *I32Ty = IntegerType::getInt32Ty(PhiTy->getContext());
-      auto *ScalarFactorVPV =
+      auto *ScaleFactorVPV =
           Plan->getOrAddLiveIn(ConstantInt::get(I32Ty, ScaleFactor));
       VPValue *StartV = PHBuilder.createNaryOp(
           VPInstruction::ReductionStartVector,
-          {PhiR->getStartValue(), Iden, ScalarFactorVPV},
+          {PhiR->getStartValue(), Iden, ScaleFactorVPV},
           PhiTy->isFloatingPointTy() ? RdxDesc.getFastMathFlags()
                                      : FastMathFlags());
       PhiR->setOperand(0, StartV);

llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp

@@ -397,6 +397,10 @@ static unsigned getVFScaleFactor(VPRecipeBase *R) {
     return RR->getVFScaleFactor();
   if (auto *RR = dyn_cast<VPPartialReductionRecipe>(R))
     return RR->getVFScaleFactor();
+  if (auto *VPI = dyn_cast<VPInstruction>(R))
+    assert(
+        VPI->getOpcode() != VPInstruction::ReductionStartVector &&
+        "getting scaling factor of reduction-start-vector not implemented yet");
   return 1;
 }
 

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -1157,9 +1157,9 @@ static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo) {
   VPValue *StartV;
   if (match(Def, m_VPInstruction<VPInstruction::ReductionStartVector>(
                      m_VPValue(StartV), m_VPValue(), m_VPValue()))) {
-    Def->replaceUsesWithIf(StartV, [Def](const VPUser &U, unsigned Idx) {
+    Def->replaceUsesWithIf(StartV, [](const VPUser &U, unsigned Idx) {
       auto *PhiR = dyn_cast<VPReductionPHIRecipe>(&U);
-      return PhiR && Def == PhiR->getOperand(Idx) && PhiR->isInLoop();
+      return PhiR && PhiR->isInLoop();
     });
     return;
   }

llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp

@@ -227,17 +227,16 @@ void UnrollState::unrollHeaderPHIByUF(VPHeaderPHIRecipe *R,
       // (second operand) for unrolled parts. If the scaling factor is > 1,
       // create a new ReductionStartVector with the scale factor and both
       // operands set to the identity value.
+
       if (auto *VPI = dyn_cast<VPInstruction>(RdxPhi->getStartValue())) {
         if (cast<ConstantInt>(VPI->getOperand(2)->getLiveInIRValue())
-                ->getZExtValue() == 1)
+                ->getZExtValue() == 1) {
           Copy->setOperand(0, VPI->getOperand(1));
-        else {
-          if (Part == 1) {
-            auto *C = VPI->clone();
-            C->setOperand(0, C->getOperand(1));
-            C->insertAfter(VPI);
-            addUniformForAllParts(C);
-          }
+        } else if (Part == 1) {
+          auto *C = VPI->clone();
+          C->setOperand(0, C->getOperand(1));
+          C->insertAfter(VPI);
+          addUniformForAllParts(C);
         }
       }
       Copy->addOperand(getConstantVPV(Part));