[VPlan] Remove redundant transferFlags call from replicateByVF (NFC).

Flags are now passed on construction/cloning. Remove unnecessary
transferFlags call, and make code independent of VPRecipeWithIRFlags, to
support additional recipes in the future.

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp

@@ -466,7 +466,7 @@ void VPlanTransforms::unrollByUF(VPlan &Plan, unsigned UF) {
 /// definitions for operands of \DefR.
 static VPValue *
 cloneForLane(VPlan &Plan, VPBuilder &Builder, Type *IdxTy,
-             VPRecipeWithIRFlags *DefR, VPLane Lane,
+             VPSingleDefRecipe *DefR, VPLane Lane,
              const DenseMap<VPValue *, SmallVector<VPValue *>> &Def2LaneDefs) {
   VPValue *Op;
   if (match(DefR, m_VPInstruction<VPInstruction::Unpack>(m_VPValue(Op)))) {
@@ -513,7 +513,7 @@ cloneForLane(VPlan &Plan, VPBuilder &Builder, Type *IdxTy,
     NewOps.push_back(Ext);
   }
 
-  VPRecipeWithIRFlags *New;
+  VPSingleDefRecipe *New;
   if (auto *RepR = dyn_cast<VPReplicateRecipe>(DefR)) {
     // TODO: have cloning of replicate recipes also provide the desired result
     // coupled with setting its operands to NewOps (deriving IsSingleScalar and
@@ -529,7 +529,6 @@ cloneForLane(VPlan &Plan, VPBuilder &Builder, Type *IdxTy,
       New->setOperand(Idx, Op);
     }
   }
-  New->transferFlags(*DefR);
   New->insertBefore(DefR);
   return New;
 }
@@ -563,7 +562,7 @@ void VPlanTransforms::replicateByVF(VPlan &Plan, ElementCount VF) {
            cast<VPInstruction>(&R)->getOpcode() != VPInstruction::Unpack))
         continue;
 
-      auto *DefR = cast<VPRecipeWithIRFlags>(&R);
+      auto *DefR = cast<VPSingleDefRecipe>(&R);
       VPBuilder Builder(DefR);
       if (DefR->getNumUsers() == 0) {
         // Create single-scalar version of DefR for all lanes.