[SelectionDAG] Pass explicit type to lowerCallOperands. NFC.

[sanjoy]

Summary

Currently this does not change anything, but change will be used in a
later change to StatepointLowering.cpp

[atrick]

LGTM

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

public:
   void LowerCallTo(ImmutableCallSite CS, SDValue Callee, bool IsTailCall,
                    MachineBasicBlock *LandingPad = nullptr);
 
   std::pair<SDValue, SDValue> lowerCallOperands(
           ImmutableCallSite CS,
           unsigned ArgIdx,
           unsigned NumArgs,
           SDValue Callee,
-          bool UseVoidTy = false,
+          Type *ReturnTy,
           MachineBasicBlock *LandingPad = nullptr,
           bool IsPatchPoint = false);
 
   /// UpdateSplitBlock - When an MBB was split during scheduling, update the
   /// references that need to refer to the last resulting block.
   void UpdateSplitBlock(MachineBasicBlock *First, MachineBasicBlock *Last);
 
   // This function is responsible for the whole statepoint lowering process.

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

 /// \return A tuple of <return-value, token-chain>
 ///
 /// This is a helper for lowering intrinsics that follow a target calling
 /// convention or require stack pointer adjustment. Only a subset of the
 /// intrinsic's operands need to participate in the calling convention.
 std::pair<SDValue, SDValue>
 SelectionDAGBuilder::lowerCallOperands(ImmutableCallSite CS, unsigned ArgIdx,
                                        unsigned NumArgs, SDValue Callee,
-                                       bool UseVoidTy,
+                                       Type *ReturnTy,
                                        MachineBasicBlock *LandingPad,
                                        bool IsPatchPoint) {
   TargetLowering::ArgListTy Args;
   Args.reserve(NumArgs);
 
   // Populate the argument list.
   // Attributes for args start at offset 1, after the return attribute.
   for (unsigned ArgI = ArgIdx, ArgE = ArgIdx + NumArgs, AttrI = ArgIdx + 1;
        ArgI != ArgE; ++ArgI) {
     const Value *V = CS->getOperand(ArgI);
 
     assert(!V->getType()->isEmptyTy() && "Empty type passed to intrinsic.");
 
     TargetLowering::ArgListEntry Entry;
     Entry.Node = getValue(V);
     Entry.Ty = V->getType();
     Entry.setAttributes(&CS, AttrI);
     Args.push_back(Entry);
   }
 
-  Type *retTy = UseVoidTy ? Type::getVoidTy(*DAG.getContext()) : CS->getType();
   TargetLowering::CallLoweringInfo CLI(DAG);
   CLI.setDebugLoc(getCurSDLoc()).setChain(getRoot())
-    .setCallee(CS.getCallingConv(), retTy, Callee, std::move(Args), NumArgs)
+    .setCallee(CS.getCallingConv(), ReturnTy, Callee, std::move(Args), NumArgs)
     .setDiscardResult(CS->use_empty()).setIsPatchPoint(IsPatchPoint);
 
   return lowerInvokable(CLI, LandingPad);
 }
 
 /// \brief Add a stack map intrinsic call's live variable operands to a stackmap
 /// or patchpoint target node's operand list.
 ///
void SelectionDAGBuilder::visitPatchpoint(ImmutableCallSite CS,
   // Skip the four meta args: <id>, <numNopBytes>, <target>, <numArgs>
   // Intrinsics include all meta-operands up to but not including CC.
   unsigned NumMetaOpers = PatchPointOpers::CCPos;
   assert(CS.arg_size() >= NumMetaOpers + NumArgs &&
          "Not enough arguments provided to the patchpoint intrinsic");
 
   // For AnyRegCC the arguments are lowered later on manually.
   unsigned NumCallArgs = IsAnyRegCC ? 0 : NumArgs;
+  Type *ReturnTy =
+    IsAnyRegCC ? Type::getVoidTy(*DAG.getContext()) : CS->getType();
   std::pair<SDValue, SDValue> Result =
-    lowerCallOperands(CS, NumMetaOpers, NumCallArgs, Callee, IsAnyRegCC,
+    lowerCallOperands(CS, NumMetaOpers, NumCallArgs, Callee, ReturnTy,
                       LandingPad, true);
 
   SDNode *CallEnd = Result.second.getNode();
   if (HasDef && (CallEnd->getOpcode() == ISD::CopyFromReg))
     CallEnd = CallEnd->getOperand(0).getNode();
 
   /// Get a call instruction from the call sequence chain.
   /// Tail calls are not allowed.