[VPlan] Use inferScalarType in VPInstruction::ResumePhi codegen (NFC).

Use VPlan-based type analysis to retrieve type of phi node. Also adds
missing type inference for ResumePhi and ComputeReductionResult opcodes.

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp

@@ -61,10 +61,16 @@ Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPInstruction *R) {
   case Instruction::ICmp:
   case VPInstruction::ActiveLaneMask:
     return inferScalarType(R->getOperand(1));
+  case VPInstruction::ComputeReductionResult: {
+    auto *PhiR = cast<VPReductionPHIRecipe>(R->getOperand(0));
+    auto *OrigPhi = cast<PHINode>(PhiR->getUnderlyingValue());
+    return OrigPhi->getType();
+  }
   case VPInstruction::ExplicitVectorLength:
     return Type::getIntNTy(Ctx, 32);
   case VPInstruction::FirstOrderRecurrenceSplice:
   case VPInstruction::Not:
+  case VPInstruction::ResumePhi:
     return SetResultTyFromOp();
   case VPInstruction::ExtractFromEnd: {
     Type *BaseTy = inferScalarType(R->getOperand(0));

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -629,7 +629,7 @@ Value *VPInstruction::generate(VPTransformState &State) {
     Value *IncomingFromOtherPreds =
         State.get(getOperand(1), /* IsScalar */ true);
     auto *NewPhi =
-        Builder.CreatePHI(IncomingFromOtherPreds->getType(), 2, Name);
+        Builder.CreatePHI(State.TypeAnalysis.inferScalarType(this), 2, Name);
     BasicBlock *VPlanPred =
         State.CFG
             .VPBB2IRBB[cast<VPBasicBlock>(getParent()->getPredecessors()[0])];