[NFC] Refactor visitIntrinsicCall so it doesn't return a const char*

[gchatelet]

Summary

API simplification

[gchatelet]

• Fix typo

[courbet]

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

5494

Please update the comment.

7542

So this is not really an NFC as this is is no longer executed on setjmp, longjmp, and clear_cache. Here ends my knowledge, let's find reviewers who can comment on whether this is OK or not :)

[gchatelet]

• Update documentation

[sanjoy]

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

6513–6515

Needs clang-format

Also is this ever null?

7542

This change in behavior seems fine to me but CC @reames to be sure.

[gchatelet]

• clang-format

[gchatelet]

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

6513–6515

Thx.

It is indeed nullptr for X86 https://github.com/llvm-mirror/llvm/blob/master/lib/Target/X86/X86ISelLowering.h#L1124

7542

Thx for the review @sanjoy . @reames do you mind having a look?

[gchatelet]

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

7542

A gentle ping @reames

[gchatelet]

I'll submit this one shortly. @reames please let me know if you have any concerns.

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

private:
   bool visitUnaryFloatCall(const CallInst &I, unsigned Opcode);
   bool visitBinaryFloatCall(const CallInst &I, unsigned Opcode);
   void visitAtomicLoad(const LoadInst &I);
   void visitAtomicStore(const StoreInst &I);
   void visitLoadFromSwiftError(const LoadInst &I);
   void visitStoreToSwiftError(const StoreInst &I);
 
   void visitInlineAsm(ImmutableCallSite CS);
-  const char *visitIntrinsicCall(const CallInst &I, unsigned Intrinsic);
+  void visitIntrinsicCall(const CallInst &I, unsigned Intrinsic);
   void visitTargetIntrinsic(const CallInst &I, unsigned Intrinsic);
   void visitConstrainedFPIntrinsic(const ConstrainedFPIntrinsic &FPI);
 
   void visitVAStart(const CallInst &I);
   void visitVAArg(const VAArgInst &I);
   void visitVAEnd(const CallInst &I);
   void visitVACopy(const CallInst &I);
   void visitStackmap(const CallInst &I);
private:
   /// Update the DAG and DAG builder with the relevant information after
   /// a new root node has been created which could be a tail call.
   void updateDAGForMaybeTailCall(SDValue MaybeTC);
 
   /// Return the appropriate SDDbgValue based on N.
   SDDbgValue *getDbgValue(SDValue N, DILocalVariable *Variable,
                           DIExpression *Expr, const DebugLoc &dl,
                           unsigned DbgSDNodeOrder);
+
+  /// Lowers CallInst to an external symbol.
+  void lowerCallToExternalSymbol(const CallInst &I, const char *FunctionName);
 };
 
 /// This struct represents the registers (physical or virtual)
 /// that a particular set of values is assigned, and the type information about
 /// the value. The most common situation is to represent one value at a time,
 /// but struct or array values are handled element-wise as multiple values.  The
 /// splitting of aggregates is performed recursively, so that we never have
 /// aggregate-typed registers. The values at this point do not necessarily have

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

case Intrinsic::smul_fix:
     return ISD::SMULFIX;
   case Intrinsic::umul_fix:
     return ISD::UMULFIX;
   default:
     llvm_unreachable("Unhandled fixed point intrinsic");
   }
 }
 
+void SelectionDAGBuilder::lowerCallToExternalSymbol(const CallInst &I,
+                                           const char *FunctionName) {
+  assert(FunctionName && "FunctionName must not be nullptr");
+  SDValue Callee = DAG.getExternalSymbol(
+      FunctionName,
+      DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout()));
+  LowerCallTo(&I, Callee, I.isTailCall());
+}
+
 /// Lower the call to the specified intrinsic function. If we want to emit this
 /// as a call to a named external function, return the name. Otherwise, lower it
 /// and return null.
-const char *
-SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
+void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
+                                             unsigned Intrinsic) {
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SDLoc sdl = getCurSDLoc();
   DebugLoc dl = getCurDebugLoc();
   SDValue Res;
 
   switch (Intrinsic) {
   default:
     // By default, turn this into a target intrinsic node.
     visitTargetIntrinsic(I, Intrinsic);
-    return nullptr;
-  case Intrinsic::vastart:  visitVAStart(I); return nullptr;
-  case Intrinsic::vaend:    visitVAEnd(I); return nullptr;
-  case Intrinsic::vacopy:   visitVACopy(I); return nullptr;
+    return;
+  case Intrinsic::vastart:  visitVAStart(I); return;
+  case Intrinsic::vaend:    visitVAEnd(I); return;
+  case Intrinsic::vacopy:   visitVACopy(I); return;
   case Intrinsic::returnaddress:
     setValue(&I, DAG.getNode(ISD::RETURNADDR, sdl,
                              TLI.getPointerTy(DAG.getDataLayout()),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::addressofreturnaddress:
     setValue(&I, DAG.getNode(ISD::ADDROFRETURNADDR, sdl,
                              TLI.getPointerTy(DAG.getDataLayout())));
-    return nullptr;
+    return;
   case Intrinsic::sponentry:
     setValue(&I, DAG.getNode(ISD::SPONENTRY, sdl,
                              TLI.getPointerTy(DAG.getDataLayout())));
-    return nullptr;
+    return;
   case Intrinsic::frameaddress:
     setValue(&I, DAG.getNode(ISD::FRAMEADDR, sdl,
                              TLI.getPointerTy(DAG.getDataLayout()),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::read_register: {
     Value *Reg = I.getArgOperand(0);
     SDValue Chain = getRoot();
     SDValue RegName =
         DAG.getMDNode(cast<MDNode>(cast<MetadataAsValue>(Reg)->getMetadata()));
     EVT VT = TLI.getValueType(DAG.getDataLayout(), I.getType());
     Res = DAG.getNode(ISD::READ_REGISTER, sdl,
       DAG.getVTList(VT, MVT::Other), Chain, RegName);
     setValue(&I, Res);
     DAG.setRoot(Res.getValue(1));
-    return nullptr;
+    return;
   }
   case Intrinsic::write_register: {
     Value *Reg = I.getArgOperand(0);
     Value *RegValue = I.getArgOperand(1);
     SDValue Chain = getRoot();
     SDValue RegName =
         DAG.getMDNode(cast<MDNode>(cast<MetadataAsValue>(Reg)->getMetadata()));
     DAG.setRoot(DAG.getNode(ISD::WRITE_REGISTER, sdl, MVT::Other, Chain,
                             RegName, getValue(RegValue)));
-    return nullptr;
+    return;
   }
   case Intrinsic::setjmp:
-    return &"_setjmp"[!TLI.usesUnderscoreSetJmp()];
+    lowerCallToExternalSymbol(I, &"_setjmp"[!TLI.usesUnderscoreSetJmp()]);
+    return;
   case Intrinsic::longjmp:
-    return &"_longjmp"[!TLI.usesUnderscoreLongJmp()];
+    lowerCallToExternalSymbol(I, &"_longjmp"[!TLI.usesUnderscoreLongJmp()]);
+    return;
   case Intrinsic::memcpy: {
     const auto &MCI = cast<MemCpyInst>(I);
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     SDValue Op3 = getValue(I.getArgOperand(2));
     // @llvm.memcpy defines 0 and 1 to both mean no alignment.
     unsigned DstAlign = std::max<unsigned>(MCI.getDestAlignment(), 1);
     unsigned SrcAlign = std::max<unsigned>(MCI.getSourceAlignment(), 1);
     unsigned Align = MinAlign(DstAlign, SrcAlign);
     bool isVol = MCI.isVolatile();
     bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
     // FIXME: Support passing different dest/src alignments to the memcpy DAG
     // node.
     SDValue MC = DAG.getMemcpy(getRoot(), sdl, Op1, Op2, Op3, Align, isVol,
                                false, isTC,
                                MachinePointerInfo(I.getArgOperand(0)),
                                MachinePointerInfo(I.getArgOperand(1)));
     updateDAGForMaybeTailCall(MC);
-    return nullptr;
+    return;
   }
   case Intrinsic::memset: {
     const auto &MSI = cast<MemSetInst>(I);
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     SDValue Op3 = getValue(I.getArgOperand(2));
     // @llvm.memset defines 0 and 1 to both mean no alignment.
     unsigned Align = std::max<unsigned>(MSI.getDestAlignment(), 1);
     bool isVol = MSI.isVolatile();
     bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
     SDValue MS = DAG.getMemset(getRoot(), sdl, Op1, Op2, Op3, Align, isVol,
                                isTC, MachinePointerInfo(I.getArgOperand(0)));
     updateDAGForMaybeTailCall(MS);
-    return nullptr;
+    return;
   }
   case Intrinsic::memmove: {
     const auto &MMI = cast<MemMoveInst>(I);
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     SDValue Op3 = getValue(I.getArgOperand(2));
     // @llvm.memmove defines 0 and 1 to both mean no alignment.
     unsigned DstAlign = std::max<unsigned>(MMI.getDestAlignment(), 1);
     unsigned SrcAlign = std::max<unsigned>(MMI.getSourceAlignment(), 1);
     unsigned Align = MinAlign(DstAlign, SrcAlign);
     bool isVol = MMI.isVolatile();
     bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
     // FIXME: Support passing different dest/src alignments to the memmove DAG
     // node.
     SDValue MM = DAG.getMemmove(getRoot(), sdl, Op1, Op2, Op3, Align, isVol,
                                 isTC, MachinePointerInfo(I.getArgOperand(0)),
                                 MachinePointerInfo(I.getArgOperand(1)));
     updateDAGForMaybeTailCall(MM);
-    return nullptr;
+    return;
   }
   case Intrinsic::memcpy_element_unordered_atomic: {
     const AtomicMemCpyInst &MI = cast<AtomicMemCpyInst>(I);
     SDValue Dst = getValue(MI.getRawDest());
     SDValue Src = getValue(MI.getRawSource());
     SDValue Length = getValue(MI.getLength());
 
     unsigned DstAlign = MI.getDestAlignment();
     unsigned SrcAlign = MI.getSourceAlignment();
     Type *LengthTy = MI.getLength()->getType();
     unsigned ElemSz = MI.getElementSizeInBytes();
     bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
     SDValue MC = DAG.getAtomicMemcpy(getRoot(), sdl, Dst, DstAlign, Src,
                                      SrcAlign, Length, LengthTy, ElemSz, isTC,
                                      MachinePointerInfo(MI.getRawDest()),
                                      MachinePointerInfo(MI.getRawSource()));
     updateDAGForMaybeTailCall(MC);
-    return nullptr;
+    return;
   }
   case Intrinsic::memmove_element_unordered_atomic: {
     auto &MI = cast<AtomicMemMoveInst>(I);
     SDValue Dst = getValue(MI.getRawDest());
     SDValue Src = getValue(MI.getRawSource());
     SDValue Length = getValue(MI.getLength());
 
     unsigned DstAlign = MI.getDestAlignment();
     unsigned SrcAlign = MI.getSourceAlignment();
     Type *LengthTy = MI.getLength()->getType();
     unsigned ElemSz = MI.getElementSizeInBytes();
     bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
     SDValue MC = DAG.getAtomicMemmove(getRoot(), sdl, Dst, DstAlign, Src,
                                       SrcAlign, Length, LengthTy, ElemSz, isTC,
                                       MachinePointerInfo(MI.getRawDest()),
                                       MachinePointerInfo(MI.getRawSource()));
     updateDAGForMaybeTailCall(MC);
-    return nullptr;
+    return;
   }
   case Intrinsic::memset_element_unordered_atomic: {
     auto &MI = cast<AtomicMemSetInst>(I);
     SDValue Dst = getValue(MI.getRawDest());
     SDValue Val = getValue(MI.getValue());
     SDValue Length = getValue(MI.getLength());
 
     unsigned DstAlign = MI.getDestAlignment();
     Type *LengthTy = MI.getLength()->getType();
     unsigned ElemSz = MI.getElementSizeInBytes();
     bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
     SDValue MC = DAG.getAtomicMemset(getRoot(), sdl, Dst, DstAlign, Val, Length,
                                      LengthTy, ElemSz, isTC,
                                      MachinePointerInfo(MI.getRawDest()));
     updateDAGForMaybeTailCall(MC);
-    return nullptr;
+    return;
   }
   case Intrinsic::dbg_addr:
   case Intrinsic::dbg_declare: {
     const auto &DI = cast<DbgVariableIntrinsic>(I);
     DILocalVariable *Variable = DI.getVariable();
     DIExpression *Expression = DI.getExpression();
     dropDanglingDebugInfo(Variable, Expression);
     assert(Variable && "Missing variable");
 
     // Check if address has undef value.
     const Value *Address = DI.getVariableLocation();
     if (!Address || isa<UndefValue>(Address) ||
         (Address->use_empty() && !isa<Argument>(Address))) {
       LLVM_DEBUG(dbgs() << "Dropping debug info for " << DI << "\n");
-      return nullptr;
+      return;
     }
 
     bool isParameter = Variable->isParameter() || isa<Argument>(Address);
 
     // Check if this variable can be described by a frame index, typically
     // either as a static alloca or a byval parameter.
     int FI = std::numeric_limits<int>::max();
     if (const auto *AI =
case Intrinsic::dbg_declare: {
     // DBG_VALUE instructions. llvm.dbg.declare is handled as a frame index in
     // the MachineFunction variable table.
     if (FI != std::numeric_limits<int>::max()) {
       if (Intrinsic == Intrinsic::dbg_addr) {
         SDDbgValue *SDV = DAG.getFrameIndexDbgValue(
             Variable, Expression, FI, /*IsIndirect*/ true, dl, SDNodeOrder);
         DAG.AddDbgValue(SDV, getRoot().getNode(), isParameter);
       }
-      return nullptr;
+      return;
     }
 
     SDValue &N = NodeMap[Address];
     if (!N.getNode() && isa<Argument>(Address))
       // Check unused arguments map.
       N = UnusedArgNodeMap[Address];
     SDDbgValue *SDV;
     if (N.getNode()) {
       if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
         Address = BCI->getOperand(0);
       // Parameters are handled specially.
       auto FINode = dyn_cast<FrameIndexSDNode>(N.getNode());
       if (isParameter && FINode) {
         // Byval parameter. We have a frame index at this point.
         SDV =
             DAG.getFrameIndexDbgValue(Variable, Expression, FINode->getIndex(),
                                       /*IsIndirect*/ true, dl, SDNodeOrder);
       } else if (isa<Argument>(Address)) {
         // Address is an argument, so try to emit its dbg value using
         // virtual register info from the FuncInfo.ValueMap.
         EmitFuncArgumentDbgValue(Address, Variable, Expression, dl, true, N);
-        return nullptr;
+        return;
       } else {
         SDV = DAG.getDbgValue(Variable, Expression, N.getNode(), N.getResNo(),
                               true, dl, SDNodeOrder);
       }
       DAG.AddDbgValue(SDV, N.getNode(), isParameter);
     } else {
       // If Address is an argument then try to emit its dbg value using
       // virtual register info from the FuncInfo.ValueMap.
       if (!EmitFuncArgumentDbgValue(Address, Variable, Expression, dl, true,
                                     N)) {
         LLVM_DEBUG(dbgs() << "Dropping debug info for " << DI << "\n");
       }
     }
-    return nullptr;
+    return;
   }
   case Intrinsic::dbg_label: {
     const DbgLabelInst &DI = cast<DbgLabelInst>(I);
     DILabel *Label = DI.getLabel();
     assert(Label && "Missing label");
 
     SDDbgLabel *SDV;
     SDV = DAG.getDbgLabel(Label, dl, SDNodeOrder);
     DAG.AddDbgLabel(SDV);
-    return nullptr;
+    return;
   }
   case Intrinsic::dbg_value: {
     const DbgValueInst &DI = cast<DbgValueInst>(I);
     assert(DI.getVariable() && "Missing variable");
 
     DILocalVariable *Variable = DI.getVariable();
     DIExpression *Expression = DI.getExpression();
     dropDanglingDebugInfo(Variable, Expression);
     const Value *V = DI.getValue();
     if (!V)
-      return nullptr;
+      return;
 
     if (handleDebugValue(V, Variable, Expression, dl, DI.getDebugLoc(),
         SDNodeOrder))
-      return nullptr;
+      return;
 
     // TODO: Dangling debug info will eventually either be resolved or produce
     // an Undef DBG_VALUE. However in the resolution case, a gap may appear
     // between the original dbg.value location and its resolved DBG_VALUE, which
     // we should ideally fill with an extra Undef DBG_VALUE.
 
     DanglingDebugInfoMap[V].emplace_back(&DI, dl, SDNodeOrder);
-    return nullptr;
+    return;
   }
 
   case Intrinsic::eh_typeid_for: {
     // Find the type id for the given typeinfo.
     GlobalValue *GV = ExtractTypeInfo(I.getArgOperand(0));
     unsigned TypeID = DAG.getMachineFunction().getTypeIDFor(GV);
     Res = DAG.getConstant(TypeID, sdl, MVT::i32);
     setValue(&I, Res);
-    return nullptr;
+    return;
   }
 
   case Intrinsic::eh_return_i32:
   case Intrinsic::eh_return_i64:
     DAG.getMachineFunction().setCallsEHReturn(true);
     DAG.setRoot(DAG.getNode(ISD::EH_RETURN, sdl,
                             MVT::Other,
                             getControlRoot(),
                             getValue(I.getArgOperand(0)),
                             getValue(I.getArgOperand(1))));
-    return nullptr;
+    return;
   case Intrinsic::eh_unwind_init:
     DAG.getMachineFunction().setCallsUnwindInit(true);
-    return nullptr;
+    return;
   case Intrinsic::eh_dwarf_cfa:
     setValue(&I, DAG.getNode(ISD::EH_DWARF_CFA, sdl,
                              TLI.getPointerTy(DAG.getDataLayout()),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::eh_sjlj_callsite: {
     MachineModuleInfo &MMI = DAG.getMachineFunction().getMMI();
     ConstantInt *CI = dyn_cast<ConstantInt>(I.getArgOperand(0));
     assert(CI && "Non-constant call site value in eh.sjlj.callsite!");
     assert(MMI.getCurrentCallSite() == 0 && "Overlapping call sites!");
 
     MMI.setCurrentCallSite(CI->getZExtValue());
-    return nullptr;
+    return;
   }
   case Intrinsic::eh_sjlj_functioncontext: {
     // Get and store the index of the function context.
     MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
     AllocaInst *FnCtx =
       cast<AllocaInst>(I.getArgOperand(0)->stripPointerCasts());
     int FI = FuncInfo.StaticAllocaMap[FnCtx];
     MFI.setFunctionContextIndex(FI);
-    return nullptr;
+    return;
   }
   case Intrinsic::eh_sjlj_setjmp: {
     SDValue Ops[2];
     Ops[0] = getRoot();
     Ops[1] = getValue(I.getArgOperand(0));
     SDValue Op = DAG.getNode(ISD::EH_SJLJ_SETJMP, sdl,
                              DAG.getVTList(MVT::i32, MVT::Other), Ops);
     setValue(&I, Op.getValue(0));
     DAG.setRoot(Op.getValue(1));
-    return nullptr;
+    return;
   }
   case Intrinsic::eh_sjlj_longjmp:
     DAG.setRoot(DAG.getNode(ISD::EH_SJLJ_LONGJMP, sdl, MVT::Other,
                             getRoot(), getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::eh_sjlj_setup_dispatch:
     DAG.setRoot(DAG.getNode(ISD::EH_SJLJ_SETUP_DISPATCH, sdl, MVT::Other,
                             getRoot()));
-    return nullptr;
+    return;
   case Intrinsic::masked_gather:
     visitMaskedGather(I);
-    return nullptr;
+    return;
   case Intrinsic::masked_load:
     visitMaskedLoad(I);
-    return nullptr;
+    return;
   case Intrinsic::masked_scatter:
     visitMaskedScatter(I);
-    return nullptr;
+    return;
   case Intrinsic::masked_store:
     visitMaskedStore(I);
-    return nullptr;
+    return;
   case Intrinsic::masked_expandload:
     visitMaskedLoad(I, true /* IsExpanding */);
-    return nullptr;
+    return;
   case Intrinsic::masked_compressstore:
     visitMaskedStore(I, true /* IsCompressing */);
-    return nullptr;
+    return;
   case Intrinsic::x86_mmx_pslli_w:
   case Intrinsic::x86_mmx_pslli_d:
   case Intrinsic::x86_mmx_pslli_q:
   case Intrinsic::x86_mmx_psrli_w:
   case Intrinsic::x86_mmx_psrli_d:
   case Intrinsic::x86_mmx_psrli_q:
   case Intrinsic::x86_mmx_psrai_w:
   case Intrinsic::x86_mmx_psrai_d: {
     SDValue ShAmt = getValue(I.getArgOperand(1));
     if (isa<ConstantSDNode>(ShAmt)) {
       visitTargetIntrinsic(I, Intrinsic);
-      return nullptr;
+      return;
     }
     unsigned NewIntrinsic = 0;
     EVT ShAmtVT = MVT::v2i32;
     switch (Intrinsic) {
     case Intrinsic::x86_mmx_pslli_w:
       NewIntrinsic = Intrinsic::x86_mmx_psll_w;
       break;
     case Intrinsic::x86_mmx_pslli_d:
case Intrinsic::x86_mmx_psrai_d: {
     ShOps[1] = DAG.getConstant(0, sdl, MVT::i32);
     ShAmt =  DAG.getBuildVector(ShAmtVT, sdl, ShOps);
     EVT DestVT = TLI.getValueType(DAG.getDataLayout(), I.getType());
     ShAmt = DAG.getNode(ISD::BITCAST, sdl, DestVT, ShAmt);
     Res = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, sdl, DestVT,
                        DAG.getConstant(NewIntrinsic, sdl, MVT::i32),
                        getValue(I.getArgOperand(0)), ShAmt);
     setValue(&I, Res);
-    return nullptr;
+    return;
   }
   case Intrinsic::powi:
     setValue(&I, ExpandPowI(sdl, getValue(I.getArgOperand(0)),
                             getValue(I.getArgOperand(1)), DAG));
-    return nullptr;
+    return;
   case Intrinsic::log:
     setValue(&I, expandLog(sdl, getValue(I.getArgOperand(0)), DAG, TLI));
-    return nullptr;
+    return;
   case Intrinsic::log2:
     setValue(&I, expandLog2(sdl, getValue(I.getArgOperand(0)), DAG, TLI));
-    return nullptr;
+    return;
   case Intrinsic::log10:
     setValue(&I, expandLog10(sdl, getValue(I.getArgOperand(0)), DAG, TLI));
-    return nullptr;
+    return;
   case Intrinsic::exp:
     setValue(&I, expandExp(sdl, getValue(I.getArgOperand(0)), DAG, TLI));
-    return nullptr;
+    return;
   case Intrinsic::exp2:
     setValue(&I, expandExp2(sdl, getValue(I.getArgOperand(0)), DAG, TLI));
-    return nullptr;
+    return;
   case Intrinsic::pow:
     setValue(&I, expandPow(sdl, getValue(I.getArgOperand(0)),
                            getValue(I.getArgOperand(1)), DAG, TLI));
-    return nullptr;
+    return;
   case Intrinsic::sqrt:
   case Intrinsic::fabs:
   case Intrinsic::sin:
   case Intrinsic::cos:
   case Intrinsic::floor:
   case Intrinsic::ceil:
   case Intrinsic::trunc:
   case Intrinsic::rint:
case Intrinsic::canonicalize: {
     case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break;
     case Intrinsic::round:     Opcode = ISD::FROUND;     break;
     case Intrinsic::canonicalize: Opcode = ISD::FCANONICALIZE; break;
     }
 
     setValue(&I, DAG.getNode(Opcode, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   }
   case Intrinsic::minnum: {
     auto VT = getValue(I.getArgOperand(0)).getValueType();
     unsigned Opc =
         I.hasNoNaNs() && TLI.isOperationLegalOrCustom(ISD::FMINIMUM, VT)
             ? ISD::FMINIMUM
             : ISD::FMINNUM;
     setValue(&I, DAG.getNode(Opc, sdl, VT,
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1))));
-    return nullptr;
+    return;
   }
   case Intrinsic::maxnum: {
     auto VT = getValue(I.getArgOperand(0)).getValueType();
     unsigned Opc =
         I.hasNoNaNs() && TLI.isOperationLegalOrCustom(ISD::FMAXIMUM, VT)
             ? ISD::FMAXIMUM
             : ISD::FMAXNUM;
     setValue(&I, DAG.getNode(Opc, sdl, VT,
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1))));
-    return nullptr;
+    return;
   }
   case Intrinsic::minimum:
     setValue(&I, DAG.getNode(ISD::FMINIMUM, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1))));
-    return nullptr;
+    return;
   case Intrinsic::maximum:
     setValue(&I, DAG.getNode(ISD::FMAXIMUM, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1))));
-    return nullptr;
+    return;
   case Intrinsic::copysign:
     setValue(&I, DAG.getNode(ISD::FCOPYSIGN, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1))));
-    return nullptr;
+    return;
   case Intrinsic::fma:
     setValue(&I, DAG.getNode(ISD::FMA, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1)),
                              getValue(I.getArgOperand(2))));
-    return nullptr;
+    return;
   case Intrinsic::experimental_constrained_fadd:
   case Intrinsic::experimental_constrained_fsub:
   case Intrinsic::experimental_constrained_fmul:
   case Intrinsic::experimental_constrained_fdiv:
   case Intrinsic::experimental_constrained_frem:
   case Intrinsic::experimental_constrained_fma:
   case Intrinsic::experimental_constrained_sqrt:
   case Intrinsic::experimental_constrained_pow:
void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
   case Intrinsic::experimental_constrained_nearbyint:
   case Intrinsic::experimental_constrained_maxnum:
   case Intrinsic::experimental_constrained_minnum:
   case Intrinsic::experimental_constrained_ceil:
   case Intrinsic::experimental_constrained_floor:
   case Intrinsic::experimental_constrained_round:
   case Intrinsic::experimental_constrained_trunc:
     visitConstrainedFPIntrinsic(cast<ConstrainedFPIntrinsic>(I));
-    return nullptr;
+    return;
   case Intrinsic::fmuladd: {
     EVT VT = TLI.getValueType(DAG.getDataLayout(), I.getType());
     if (TM.Options.AllowFPOpFusion != FPOpFusion::Strict &&
         TLI.isFMAFasterThanFMulAndFAdd(VT)) {
       setValue(&I, DAG.getNode(ISD::FMA, sdl,
                                getValue(I.getArgOperand(0)).getValueType(),
                                getValue(I.getArgOperand(0)),
                                getValue(I.getArgOperand(1)),
                                getValue(I.getArgOperand(2))));
     } else {
       // TODO: Intrinsic calls should have fast-math-flags.
       SDValue Mul = DAG.getNode(ISD::FMUL, sdl,
                                 getValue(I.getArgOperand(0)).getValueType(),
                                 getValue(I.getArgOperand(0)),
                                 getValue(I.getArgOperand(1)));
       SDValue Add = DAG.getNode(ISD::FADD, sdl,
                                 getValue(I.getArgOperand(0)).getValueType(),
                                 Mul,
                                 getValue(I.getArgOperand(2)));
       setValue(&I, Add);
     }
-    return nullptr;
+    return;
   }
   case Intrinsic::convert_to_fp16:
     setValue(&I, DAG.getNode(ISD::BITCAST, sdl, MVT::i16,
                              DAG.getNode(ISD::FP_ROUND, sdl, MVT::f16,
                                          getValue(I.getArgOperand(0)),
                                          DAG.getTargetConstant(0, sdl,
                                                                MVT::i32))));
-    return nullptr;
+    return;
   case Intrinsic::convert_from_fp16:
     setValue(&I, DAG.getNode(ISD::FP_EXTEND, sdl,
                              TLI.getValueType(DAG.getDataLayout(), I.getType()),
                              DAG.getNode(ISD::BITCAST, sdl, MVT::f16,
                                          getValue(I.getArgOperand(0)))));
-    return nullptr;
+    return;
   case Intrinsic::pcmarker: {
     SDValue Tmp = getValue(I.getArgOperand(0));
     DAG.setRoot(DAG.getNode(ISD::PCMARKER, sdl, MVT::Other, getRoot(), Tmp));
-    return nullptr;
+    return;
   }
   case Intrinsic::readcyclecounter: {
     SDValue Op = getRoot();
     Res = DAG.getNode(ISD::READCYCLECOUNTER, sdl,
                       DAG.getVTList(MVT::i64, MVT::Other), Op);
     setValue(&I, Res);
     DAG.setRoot(Res.getValue(1));
-    return nullptr;
+    return;
   }
   case Intrinsic::bitreverse:
     setValue(&I, DAG.getNode(ISD::BITREVERSE, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::bswap:
     setValue(&I, DAG.getNode(ISD::BSWAP, sdl,
                              getValue(I.getArgOperand(0)).getValueType(),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::cttz: {
     SDValue Arg = getValue(I.getArgOperand(0));
     ConstantInt *CI = cast<ConstantInt>(I.getArgOperand(1));
     EVT Ty = Arg.getValueType();
     setValue(&I, DAG.getNode(CI->isZero() ? ISD::CTTZ : ISD::CTTZ_ZERO_UNDEF,
                              sdl, Ty, Arg));
-    return nullptr;
+    return;
   }
   case Intrinsic::ctlz: {
     SDValue Arg = getValue(I.getArgOperand(0));
     ConstantInt *CI = cast<ConstantInt>(I.getArgOperand(1));
     EVT Ty = Arg.getValueType();
     setValue(&I, DAG.getNode(CI->isZero() ? ISD::CTLZ : ISD::CTLZ_ZERO_UNDEF,
                              sdl, Ty, Arg));
-    return nullptr;
+    return;
   }
   case Intrinsic::ctpop: {
     SDValue Arg = getValue(I.getArgOperand(0));
     EVT Ty = Arg.getValueType();
     setValue(&I, DAG.getNode(ISD::CTPOP, sdl, Ty, Arg));
-    return nullptr;
+    return;
   }
   case Intrinsic::fshl:
   case Intrinsic::fshr: {
     bool IsFSHL = Intrinsic == Intrinsic::fshl;
     SDValue X = getValue(I.getArgOperand(0));
     SDValue Y = getValue(I.getArgOperand(1));
     SDValue Z = getValue(I.getArgOperand(2));
     EVT VT = X.getValueType();
     SDValue BitWidthC = DAG.getConstant(VT.getScalarSizeInBits(), sdl, VT);
     SDValue Zero = DAG.getConstant(0, sdl, VT);
     SDValue ShAmt = DAG.getNode(ISD::UREM, sdl, VT, Z, BitWidthC);
 
     auto FunnelOpcode = IsFSHL ? ISD::FSHL : ISD::FSHR;
     if (TLI.isOperationLegalOrCustom(FunnelOpcode, VT)) {
       setValue(&I, DAG.getNode(FunnelOpcode, sdl, VT, X, Y, Z));
-      return nullptr;
+      return;
     }
 
     // When X == Y, this is rotate. If the data type has a power-of-2 size, we
     // avoid the select that is necessary in the general case to filter out
     // the 0-shift possibility that leads to UB.
     if (X == Y && isPowerOf2_32(VT.getScalarSizeInBits())) {
       auto RotateOpcode = IsFSHL ? ISD::ROTL : ISD::ROTR;
       if (TLI.isOperationLegalOrCustom(RotateOpcode, VT)) {
         setValue(&I, DAG.getNode(RotateOpcode, sdl, VT, X, Z));
-        return nullptr;
+        return;
       }
 
       // Some targets only rotate one way. Try the opposite direction.
       RotateOpcode = IsFSHL ? ISD::ROTR : ISD::ROTL;
       if (TLI.isOperationLegalOrCustom(RotateOpcode, VT)) {
         // Negate the shift amount because it is safe to ignore the high bits.
         SDValue NegShAmt = DAG.getNode(ISD::SUB, sdl, VT, Zero, Z);
         setValue(&I, DAG.getNode(RotateOpcode, sdl, VT, X, NegShAmt));
-        return nullptr;
+        return;
       }
 
       // fshl (rotl): (X << (Z % BW)) | (X >> ((0 - Z) % BW))
       // fshr (rotr): (X << ((0 - Z) % BW)) | (X >> (Z % BW))
       SDValue NegZ = DAG.getNode(ISD::SUB, sdl, VT, Zero, Z);
       SDValue NShAmt = DAG.getNode(ISD::UREM, sdl, VT, NegZ, BitWidthC);
       SDValue ShX = DAG.getNode(ISD::SHL, sdl, VT, X, IsFSHL ? ShAmt : NShAmt);
       SDValue ShY = DAG.getNode(ISD::SRL, sdl, VT, X, IsFSHL ? NShAmt : ShAmt);
       setValue(&I, DAG.getNode(ISD::OR, sdl, VT, ShX, ShY));
-      return nullptr;
+      return;
     }
 
     // fshl: (X << (Z % BW)) | (Y >> (BW - (Z % BW)))
     // fshr: (X << (BW - (Z % BW))) | (Y >> (Z % BW))
     SDValue InvShAmt = DAG.getNode(ISD::SUB, sdl, VT, BitWidthC, ShAmt);
     SDValue ShX = DAG.getNode(ISD::SHL, sdl, VT, X, IsFSHL ? ShAmt : InvShAmt);
     SDValue ShY = DAG.getNode(ISD::SRL, sdl, VT, Y, IsFSHL ? InvShAmt : ShAmt);
     SDValue Or = DAG.getNode(ISD::OR, sdl, VT, ShX, ShY);
 
     // If (Z % BW == 0), then the opposite direction shift is shift-by-bitwidth,
     // and that is undefined. We must compare and select to avoid UB.
     EVT CCVT = MVT::i1;
     if (VT.isVector())
       CCVT = EVT::getVectorVT(*Context, CCVT, VT.getVectorNumElements());
 
     // For fshl, 0-shift returns the 1st arg (X).
     // For fshr, 0-shift returns the 2nd arg (Y).
     SDValue IsZeroShift = DAG.getSetCC(sdl, CCVT, ShAmt, Zero, ISD::SETEQ);
     setValue(&I, DAG.getSelect(sdl, VT, IsZeroShift, IsFSHL ? X : Y, Or));
-    return nullptr;
+    return;
   }
   case Intrinsic::sadd_sat: {
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     setValue(&I, DAG.getNode(ISD::SADDSAT, sdl, Op1.getValueType(), Op1, Op2));
-    return nullptr;
+    return;
   }
   case Intrinsic::uadd_sat: {
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     setValue(&I, DAG.getNode(ISD::UADDSAT, sdl, Op1.getValueType(), Op1, Op2));
-    return nullptr;
+    return;
   }
   case Intrinsic::ssub_sat: {
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     setValue(&I, DAG.getNode(ISD::SSUBSAT, sdl, Op1.getValueType(), Op1, Op2));
-    return nullptr;
+    return;
   }
   case Intrinsic::usub_sat: {
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     setValue(&I, DAG.getNode(ISD::USUBSAT, sdl, Op1.getValueType(), Op1, Op2));
-    return nullptr;
+    return;
   }
   case Intrinsic::smul_fix:
   case Intrinsic::umul_fix: {
     SDValue Op1 = getValue(I.getArgOperand(0));
     SDValue Op2 = getValue(I.getArgOperand(1));
     SDValue Op3 = getValue(I.getArgOperand(2));
     setValue(&I, DAG.getNode(FixedPointIntrinsicToOpcode(Intrinsic), sdl,
                              Op1.getValueType(), Op1, Op2, Op3));
-    return nullptr;
+    return;
   }
   case Intrinsic::stacksave: {
     SDValue Op = getRoot();
     Res = DAG.getNode(
         ISD::STACKSAVE, sdl,
         DAG.getVTList(TLI.getPointerTy(DAG.getDataLayout()), MVT::Other), Op);
     setValue(&I, Res);
     DAG.setRoot(Res.getValue(1));
-    return nullptr;
+    return;
   }
   case Intrinsic::stackrestore:
     Res = getValue(I.getArgOperand(0));
     DAG.setRoot(DAG.getNode(ISD::STACKRESTORE, sdl, MVT::Other, getRoot(), Res));
-    return nullptr;
+    return;
   case Intrinsic::get_dynamic_area_offset: {
     SDValue Op = getRoot();
     EVT PtrTy = TLI.getPointerTy(DAG.getDataLayout());
     EVT ResTy = TLI.getValueType(DAG.getDataLayout(), I.getType());
     // Result type for @llvm.get.dynamic.area.offset should match PtrTy for
     // target.
     if (PtrTy != ResTy)
       report_fatal_error("Wrong result type for @llvm.get.dynamic.area.offset"
                          " intrinsic!");
     Res = DAG.getNode(ISD::GET_DYNAMIC_AREA_OFFSET, sdl, DAG.getVTList(ResTy),
                       Op);
     DAG.setRoot(Op);
     setValue(&I, Res);
-    return nullptr;
+    return;
   }
   case Intrinsic::stackguard: {
     EVT PtrTy = TLI.getPointerTy(DAG.getDataLayout());
     MachineFunction &MF = DAG.getMachineFunction();
     const Module &M = *MF.getFunction().getParent();
     SDValue Chain = getRoot();
     if (TLI.useLoadStackGuardNode()) {
       Res = getLoadStackGuard(DAG, sdl, Chain);
     } else {
       const Value *Global = TLI.getSDagStackGuard(M);
       unsigned Align = DL->getPrefTypeAlignment(Global->getType());
       Res = DAG.getLoad(PtrTy, sdl, Chain, getValue(Global),
                         MachinePointerInfo(Global, 0), Align,
                         MachineMemOperand::MOVolatile);
     }
     if (TLI.useStackGuardXorFP())
       Res = TLI.emitStackGuardXorFP(DAG, Res, sdl);
     DAG.setRoot(Chain);
     setValue(&I, Res);
-    return nullptr;
+    return;
   }
   case Intrinsic::stackprotector: {
     // Emit code into the DAG to store the stack guard onto the stack.
     MachineFunction &MF = DAG.getMachineFunction();
     MachineFrameInfo &MFI = MF.getFrameInfo();
     EVT PtrTy = TLI.getPointerTy(DAG.getDataLayout());
     SDValue Src, Chain = getRoot();
 
case Intrinsic::stackprotector: {
     SDValue FIN = DAG.getFrameIndex(FI, PtrTy);
 
     // Store the stack protector onto the stack.
     Res = DAG.getStore(Chain, sdl, Src, FIN, MachinePointerInfo::getFixedStack(
                                                  DAG.getMachineFunction(), FI),
                        /* Alignment = */ 0, MachineMemOperand::MOVolatile);
     setValue(&I, Res);
     DAG.setRoot(Res);
-    return nullptr;
+    return;
   }
   case Intrinsic::objectsize: {
     // If we don't know by now, we're never going to know.
     ConstantInt *CI = dyn_cast<ConstantInt>(I.getArgOperand(1));
 
     assert(CI && "Non-constant type in __builtin_object_size?");
 
     SDValue Arg = getValue(I.getCalledValue());
     EVT Ty = Arg.getValueType();
 
     if (CI->isZero())
       Res = DAG.getConstant(-1ULL, sdl, Ty);
     else
       Res = DAG.getConstant(0, sdl, Ty);
 
     setValue(&I, Res);
-    return nullptr;
+    return;
   }
 
   case Intrinsic::is_constant:
     // If this wasn't constant-folded away by now, then it's not a
     // constant.
     setValue(&I, DAG.getConstant(0, sdl, MVT::i1));
-    return nullptr;
+    return;
 
   case Intrinsic::annotation:
   case Intrinsic::ptr_annotation:
   case Intrinsic::launder_invariant_group:
   case Intrinsic::strip_invariant_group:
     // Drop the intrinsic, but forward the value
     setValue(&I, getValue(I.getOperand(0)));
-    return nullptr;
+    return;
   case Intrinsic::assume:
   case Intrinsic::var_annotation:
   case Intrinsic::sideeffect:
     // Discard annotate attributes, assumptions, and artificial side-effects.
-    return nullptr;
+    return;
 
   case Intrinsic::codeview_annotation: {
     // Emit a label associated with this metadata.
     MachineFunction &MF = DAG.getMachineFunction();
     MCSymbol *Label =
         MF.getMMI().getContext().createTempSymbol("annotation", true);
     Metadata *MD = cast<MetadataAsValue>(I.getArgOperand(0))->getMetadata();
     MF.addCodeViewAnnotation(Label, cast<MDNode>(MD));
     Res = DAG.getLabelNode(ISD::ANNOTATION_LABEL, sdl, getRoot(), Label);
     DAG.setRoot(Res);
-    return nullptr;
+    return;
   }
 
   case Intrinsic::init_trampoline: {
     const Function *F = cast<Function>(I.getArgOperand(1)->stripPointerCasts());
 
     SDValue Ops[6];
     Ops[0] = getRoot();
     Ops[1] = getValue(I.getArgOperand(0));
     Ops[2] = getValue(I.getArgOperand(1));
     Ops[3] = getValue(I.getArgOperand(2));
     Ops[4] = DAG.getSrcValue(I.getArgOperand(0));
     Ops[5] = DAG.getSrcValue(F);
 
     Res = DAG.getNode(ISD::INIT_TRAMPOLINE, sdl, MVT::Other, Ops);
 
     DAG.setRoot(Res);
-    return nullptr;
+    return;
   }
   case Intrinsic::adjust_trampoline:
     setValue(&I, DAG.getNode(ISD::ADJUST_TRAMPOLINE, sdl,
                              TLI.getPointerTy(DAG.getDataLayout()),
                              getValue(I.getArgOperand(0))));
-    return nullptr;
+    return;
   case Intrinsic::gcroot: {
     assert(DAG.getMachineFunction().getFunction().hasGC() &&
            "only valid in functions with gc specified, enforced by Verifier");
     assert(GFI && "implied by previous");
     const Value *Alloca = I.getArgOperand(0)->stripPointerCasts();
     const Constant *TypeMap = cast<Constant>(I.getArgOperand(1));
 
     FrameIndexSDNode *FI = cast<FrameIndexSDNode>(getValue(Alloca).getNode());
     GFI->addStackRoot(FI->getIndex(), TypeMap);
-    return nullptr;
+    return;
   }
   case Intrinsic::gcread:
   case Intrinsic::gcwrite:
     llvm_unreachable("GC failed to lower gcread/gcwrite intrinsics!");
   case Intrinsic::flt_rounds:
     setValue(&I, DAG.getNode(ISD::FLT_ROUNDS_, sdl, MVT::i32));
-    return nullptr;
+    return;
 
   case Intrinsic::expect:
     // Just replace __builtin_expect(exp, c) with EXP.
     setValue(&I, getValue(I.getArgOperand(0)));
-    return nullptr;
+    return;
 
   case Intrinsic::debugtrap:
   case Intrinsic::trap: {
     StringRef TrapFuncName =
         I.getAttributes()
             .getAttribute(AttributeList::FunctionIndex, "trap-func-name")
             .getValueAsString();
     if (TrapFuncName.empty()) {
       ISD::NodeType Op = (Intrinsic == Intrinsic::trap) ?
         ISD::TRAP : ISD::DEBUGTRAP;
       DAG.setRoot(DAG.getNode(Op, sdl,MVT::Other, getRoot()));
-      return nullptr;
+      return;
     }
     TargetLowering::ArgListTy Args;
 
     TargetLowering::CallLoweringInfo CLI(DAG);
     CLI.setDebugLoc(sdl).setChain(getRoot()).setLibCallee(
         CallingConv::C, I.getType(),
         DAG.getExternalSymbol(TrapFuncName.data(),
                               TLI.getPointerTy(DAG.getDataLayout())),
         std::move(Args));
 
     std::pair<SDValue, SDValue> Result = TLI.LowerCallTo(CLI);
     DAG.setRoot(Result.second);
-    return nullptr;
+    return;
   }
 
   case Intrinsic::uadd_with_overflow:
   case Intrinsic::sadd_with_overflow:
   case Intrinsic::usub_with_overflow:
   case Intrinsic::ssub_with_overflow:
   case Intrinsic::umul_with_overflow:
   case Intrinsic::smul_with_overflow: {
case Intrinsic::smul_with_overflow: {
     EVT ResultVT = Op1.getValueType();
     EVT OverflowVT = MVT::i1;
     if (ResultVT.isVector())
       OverflowVT = EVT::getVectorVT(
           *Context, OverflowVT, ResultVT.getVectorNumElements());
 
     SDVTList VTs = DAG.getVTList(ResultVT, OverflowVT);
     setValue(&I, DAG.getNode(Op, sdl, VTs, Op1, Op2));
-    return nullptr;
+    return;
   }
   case Intrinsic::prefetch: {
     SDValue Ops[5];
     unsigned rw = cast<ConstantInt>(I.getArgOperand(1))->getZExtValue();
     auto Flags = rw == 0 ? MachineMemOperand::MOLoad :MachineMemOperand::MOStore;
     Ops[0] = DAG.getRoot();
     Ops[1] = getValue(I.getArgOperand(0));
     Ops[2] = getValue(I.getArgOperand(1));
     Ops[3] = getValue(I.getArgOperand(2));
     Ops[4] = getValue(I.getArgOperand(3));
     SDValue Result = DAG.getMemIntrinsicNode(ISD::PREFETCH, sdl,
                                              DAG.getVTList(MVT::Other), Ops,
                                              EVT::getIntegerVT(*Context, 8),
                                              MachinePointerInfo(I.getArgOperand(0)),
                                              0, /* align */
                                              Flags);
 
     // Chain the prefetch in parallell with any pending loads, to stay out of
     // the way of later optimizations.
     PendingLoads.push_back(Result);
     Result = getRoot();
     DAG.setRoot(Result);
-    return nullptr;
+    return;
   }
   case Intrinsic::lifetime_start:
   case Intrinsic::lifetime_end: {
     bool IsStart = (Intrinsic == Intrinsic::lifetime_start);
     // Stack coloring is not enabled in O0, discard region information.
     if (TM.getOptLevel() == CodeGenOpt::None)
-      return nullptr;
+      return;
 
     const int64_t ObjectSize =
         cast<ConstantInt>(I.getArgOperand(0))->getSExtValue();
     Value *const ObjectPtr = I.getArgOperand(1);
     SmallVector<const Value *, 4> Allocas;
     GetUnderlyingObjects(ObjectPtr, Allocas, *DL);
 
     for (SmallVectorImpl<const Value*>::iterator Object = Allocas.begin(),
            E = Allocas.end(); Object != E; ++Object) {
       const AllocaInst *LifetimeObject = dyn_cast_or_null<AllocaInst>(*Object);
 
       // Could not find an Alloca.
       if (!LifetimeObject)
         continue;
 
       // First check that the Alloca is static, otherwise it won't have a
       // valid frame index.
       auto SI = FuncInfo.StaticAllocaMap.find(LifetimeObject);
       if (SI == FuncInfo.StaticAllocaMap.end())
-        return nullptr;
+        return;
 
       const int FrameIndex = SI->second;
       int64_t Offset;
       if (GetPointerBaseWithConstantOffset(
               ObjectPtr, Offset, DAG.getDataLayout()) != LifetimeObject)
         Offset = -1; // Cannot determine offset from alloca to lifetime object.
       Res = DAG.getLifetimeNode(IsStart, sdl, getRoot(), FrameIndex, ObjectSize,
                                 Offset);
       DAG.setRoot(Res);
     }
-    return nullptr;
+    return;
   }
   case Intrinsic::invariant_start:
     // Discard region information.
     setValue(&I, DAG.getUNDEF(TLI.getPointerTy(DAG.getDataLayout())));
-    return nullptr;
+    return;
   case Intrinsic::invariant_end:
     // Discard region information.
-    return nullptr;
+    return;
   case Intrinsic::clear_cache:
-    return TLI.getClearCacheBuiltinName();
+    if(const char* FunctionName = TLI.getClearCacheBuiltinName())
+      lowerCallToExternalSymbol(I, FunctionName);
+    return;
   case Intrinsic::donothing:
     // ignore
-    return nullptr;
+    return;
   case Intrinsic::experimental_stackmap:
     visitStackmap(I);
-    return nullptr;
+    return;
   case Intrinsic::experimental_patchpoint_void:
   case Intrinsic::experimental_patchpoint_i64:
     visitPatchpoint(&I);
-    return nullptr;
+    return;
   case Intrinsic::experimental_gc_statepoint:
     LowerStatepoint(ImmutableStatepoint(&I));
-    return nullptr;
+    return;
   case Intrinsic::experimental_gc_result:
     visitGCResult(cast<GCResultInst>(I));
-    return nullptr;
+    return;
   case Intrinsic::experimental_gc_relocate:
     visitGCRelocate(cast<GCRelocateInst>(I));
-    return nullptr;
+    return;
   case Intrinsic::instrprof_increment:
     llvm_unreachable("instrprof failed to lower an increment");
   case Intrinsic::instrprof_value_profile:
     llvm_unreachable("instrprof failed to lower a value profiling call");
   case Intrinsic::localescape: {
     MachineFunction &MF = DAG.getMachineFunction();
     const TargetInstrInfo *TII = DAG.getSubtarget().getInstrInfo();
 
for (unsigned Idx = 0, E = I.getNumArgOperands(); Idx < E; ++Idx) {
           MF.getMMI().getContext().getOrCreateFrameAllocSymbol(
               GlobalValue::dropLLVMManglingEscape(MF.getName()), Idx);
       BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, dl,
               TII->get(TargetOpcode::LOCAL_ESCAPE))
           .addSym(FrameAllocSym)
           .addFrameIndex(FI);
     }
 
-    return nullptr;
+    return;
   }
 
   case Intrinsic::localrecover: {
     // i8* @llvm.localrecover(i8* %fn, i8* %fp, i32 %idx)
     MachineFunction &MF = DAG.getMachineFunction();
     MVT PtrVT = TLI.getPointerTy(DAG.getDataLayout(), 0);
 
     // Get the symbol that defines the frame offset.
SDValue OffsetVal =
         DAG.getNode(ISD::LOCAL_RECOVER, sdl, PtrVT, OffsetSym);
 
     // Add the offset to the FP.
     Value *FP = I.getArgOperand(1);
     SDValue FPVal = getValue(FP);
     SDValue Add = DAG.getNode(ISD::ADD, sdl, PtrVT, FPVal, OffsetVal);
     setValue(&I, Add);
 
-    return nullptr;
+    return;
   }
 
   case Intrinsic::eh_exceptionpointer:
   case Intrinsic::eh_exceptioncode: {
     // Get the exception pointer vreg, copy from it, and resize it to fit.
     const auto *CPI = cast<CatchPadInst>(I.getArgOperand(0));
     MVT PtrVT = TLI.getPointerTy(DAG.getDataLayout());
     const TargetRegisterClass *PtrRC = TLI.getRegClassFor(PtrVT);
     unsigned VReg = FuncInfo.getCatchPadExceptionPointerVReg(CPI, PtrRC);
     SDValue N =
         DAG.getCopyFromReg(DAG.getEntryNode(), getCurSDLoc(), VReg, PtrVT);
     if (Intrinsic == Intrinsic::eh_exceptioncode)
       N = DAG.getZExtOrTrunc(N, getCurSDLoc(), MVT::i32);
     setValue(&I, N);
-    return nullptr;
+    return;
   }
   case Intrinsic::xray_customevent: {
     // Here we want to make sure that the intrinsic behaves as if it has a
     // specific calling convention, and only for x86_64.
     // FIXME: Support other platforms later.
     const auto &Triple = DAG.getTarget().getTargetTriple();
     if (Triple.getArch() != Triple::x86_64 || !Triple.isOSLinux())
-      return nullptr;
+      return;
 
     SDLoc DL = getCurSDLoc();
     SmallVector<SDValue, 8> Ops;
 
     // We want to say that we always want the arguments in registers.
     SDValue LogEntryVal = getValue(I.getArgOperand(0));
     SDValue StrSizeVal = getValue(I.getArgOperand(1));
     SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
     SDValue Chain = getRoot();
     Ops.push_back(LogEntryVal);
     Ops.push_back(StrSizeVal);
     Ops.push_back(Chain);
 
     // We need to enforce the calling convention for the callsite, so that
     // argument ordering is enforced correctly, and that register allocation can
     // see that some registers may be assumed clobbered and have to preserve
     // them across calls to the intrinsic.
     MachineSDNode *MN = DAG.getMachineNode(TargetOpcode::PATCHABLE_EVENT_CALL,
                                            DL, NodeTys, Ops);
     SDValue patchableNode = SDValue(MN, 0);
     DAG.setRoot(patchableNode);
     setValue(&I, patchableNode);
-    return nullptr;
+    return;
   }
   case Intrinsic::xray_typedevent: {
     // Here we want to make sure that the intrinsic behaves as if it has a
     // specific calling convention, and only for x86_64.
     // FIXME: Support other platforms later.
     const auto &Triple = DAG.getTarget().getTargetTriple();
     if (Triple.getArch() != Triple::x86_64 || !Triple.isOSLinux())
-      return nullptr;
+      return;
 
     SDLoc DL = getCurSDLoc();
     SmallVector<SDValue, 8> Ops;
 
     // We want to say that we always want the arguments in registers.
     // It's unclear to me how manipulating the selection DAG here forces callers
     // to provide arguments in registers instead of on the stack.
     SDValue LogTypeId = getValue(I.getArgOperand(0));
case Intrinsic::xray_typedevent: {
     // argument ordering is enforced correctly, and that register allocation can
     // see that some registers may be assumed clobbered and have to preserve
     // them across calls to the intrinsic.
     MachineSDNode *MN = DAG.getMachineNode(
         TargetOpcode::PATCHABLE_TYPED_EVENT_CALL, DL, NodeTys, Ops);
     SDValue patchableNode = SDValue(MN, 0);
     DAG.setRoot(patchableNode);
     setValue(&I, patchableNode);
-    return nullptr;
+    return;
   }
   case Intrinsic::experimental_deoptimize:
     LowerDeoptimizeCall(&I);
-    return nullptr;
+    return;
 
   case Intrinsic::experimental_vector_reduce_fadd:
   case Intrinsic::experimental_vector_reduce_fmul:
   case Intrinsic::experimental_vector_reduce_add:
   case Intrinsic::experimental_vector_reduce_mul:
   case Intrinsic::experimental_vector_reduce_and:
   case Intrinsic::experimental_vector_reduce_or:
   case Intrinsic::experimental_vector_reduce_xor:
   case Intrinsic::experimental_vector_reduce_smax:
   case Intrinsic::experimental_vector_reduce_smin:
   case Intrinsic::experimental_vector_reduce_umax:
   case Intrinsic::experimental_vector_reduce_umin:
   case Intrinsic::experimental_vector_reduce_fmax:
   case Intrinsic::experimental_vector_reduce_fmin:
     visitVectorReduce(I, Intrinsic);
-    return nullptr;
+    return;
 
   case Intrinsic::icall_branch_funnel: {
     SmallVector<SDValue, 16> Ops;
     Ops.push_back(DAG.getRoot());
     Ops.push_back(getValue(I.getArgOperand(0)));
 
     int64_t Offset;
     auto *Base = dyn_cast<GlobalObject>(GetPointerBaseWithConstantOffset(
case Intrinsic::icall_branch_funnel: {
     }
 
     SDValue N(DAG.getMachineNode(TargetOpcode::ICALL_BRANCH_FUNNEL,
                                  getCurSDLoc(), MVT::Other, Ops),
               0);
     DAG.setRoot(N);
     setValue(&I, N);
     HasTailCall = true;
-    return nullptr;
+    return;
   }
 
   case Intrinsic::wasm_landingpad_index:
     // Information this intrinsic contained has been transferred to
     // MachineFunction in SelectionDAGISel::PrepareEHLandingPad. We can safely
     // delete it now.
-    return nullptr;
+    return;
   }
 }
 
 void SelectionDAGBuilder::visitConstrainedFPIntrinsic(
     const ConstrainedFPIntrinsic &FPI) {
   SDLoc sdl = getCurSDLoc();
   unsigned Opcode;
   switch (FPI.getIntrinsicID()) {

 
 void SelectionDAGBuilder::visitCall(const CallInst &I) {
   // Handle inline assembly differently.
   if (isa<InlineAsm>(I.getCalledValue())) {
     visitInlineAsm(&I);
     return;
   }
 
-  const char *RenameFn = nullptr;
   if (Function *F = I.getCalledFunction()) {
     if (F->isDeclaration()) {
       // Is this an LLVM intrinsic or a target-specific intrinsic?
       unsigned IID = F->getIntrinsicID();
       if (!IID)
         if (const TargetIntrinsicInfo *II = TM.getIntrinsicInfo())
           IID = II->getIntrinsicID(F);
 
       if (IID) {
-        RenameFn = visitIntrinsicCall(I, IID);
-        if (!RenameFn)
-          return;
+        visitIntrinsicCall(I, IID);
       }
     }
 
     // Check for well-known libc/libm calls.  If the function is internal, it
     // can't be a library call.  Don't do the check if marked as nobuiltin for
     // some reason or the call site requires strict floating point semantics.
     LibFunc Func;
     if (!I.isNoBuiltin() && !I.isStrictFP() && !F->hasLocalLinkage() &&
if (!I.isNoBuiltin() && !I.isStrictFP() && !F->hasLocalLinkage() &&
       case LibFunc_strnlen:
         if (visitStrNLenCall(I))
           return;
         break;
       }
     }
   }
 
-  SDValue Callee;
-  if (!RenameFn)
-    Callee = getValue(I.getCalledValue());
-  else
-    Callee = DAG.getExternalSymbol(
-        RenameFn,
-        DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout()));
-
   // Deopt bundles are lowered in LowerCallSiteWithDeoptBundle, and we don't
   // have to do anything here to lower funclet bundles.
   assert(!I.hasOperandBundlesOtherThan(
              {LLVMContext::OB_deopt, LLVMContext::OB_funclet}) &&
          "Cannot lower calls with arbitrary operand bundles!");
 
+  SDValue Callee = getValue(I.getCalledValue());
+
   if (I.countOperandBundlesOfType(LLVMContext::OB_deopt))
     LowerCallSiteWithDeoptBundle(&I, Callee, nullptr);
   else
     // Check if we can potentially perform a tail call. More detailed checking
     // is be done within LowerCallTo, after more information about the call is
     // known.
     LowerCallTo(&I, Callee, I.isTailCall());
 }