//===-- MSP430ISelLowering.cpp - MSP430 DAG Lowering Implementation ------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the MSP430TargetLowering class. // //===----------------------------------------------------------------------===// #define DEBUG_TYPE "msp430-lower" #include "MSP430ISelLowering.h" #include "MSP430.h" #include "MSP430TargetMachine.h" #include "MSP430Subtarget.h" #include "llvm/DerivedTypes.h" #include "llvm/Function.h" #include "llvm/Intrinsics.h" #include "llvm/CallingConv.h" #include "llvm/GlobalVariable.h" #include "llvm/GlobalAlias.h" #include "llvm/CodeGen/CallingConvLower.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/PseudoSourceValue.h" #include "llvm/CodeGen/SelectionDAGISel.h" #include "llvm/CodeGen/ValueTypes.h" #include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/ADT/VectorExtras.h" using namespace llvm; MSP430TargetLowering::MSP430TargetLowering(MSP430TargetMachine &tm) : TargetLowering(tm, new TargetLoweringObjectFileELF()), Subtarget(*tm.getSubtargetImpl()), TM(tm) { // Set up the register classes. addRegisterClass(MVT::i8, MSP430::GR8RegisterClass); addRegisterClass(MVT::i16, MSP430::GR16RegisterClass); // Compute derived properties from the register classes computeRegisterProperties(); // Provide all sorts of operation actions // Division is expensive setIntDivIsCheap(false); // Even if we have only 1 bit shift here, we can perform // shifts of the whole bitwidth 1 bit per step. setShiftAmountType(MVT::i8); setStackPointerRegisterToSaveRestore(MSP430::SPW); setBooleanContents(ZeroOrOneBooleanContent); setSchedulingPreference(SchedulingForLatency); setLoadExtAction(ISD::EXTLOAD, MVT::i1, Promote); setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote); setLoadExtAction(ISD::ZEXTLOAD, MVT::i1, Promote); setLoadExtAction(ISD::SEXTLOAD, MVT::i8, Expand); setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand); // We don't have any truncstores setTruncStoreAction(MVT::i16, MVT::i8, Expand); setOperationAction(ISD::SRA, MVT::i8, Custom); setOperationAction(ISD::SHL, MVT::i8, Custom); setOperationAction(ISD::SRL, MVT::i8, Custom); setOperationAction(ISD::SRA, MVT::i16, Custom); setOperationAction(ISD::SHL, MVT::i16, Custom); setOperationAction(ISD::SRL, MVT::i16, Custom); setOperationAction(ISD::ROTL, MVT::i8, Expand); setOperationAction(ISD::ROTR, MVT::i8, Expand); setOperationAction(ISD::ROTL, MVT::i16, Expand); setOperationAction(ISD::ROTR, MVT::i16, Expand); setOperationAction(ISD::GlobalAddress, MVT::i16, Custom); setOperationAction(ISD::ExternalSymbol, MVT::i16, Custom); setOperationAction(ISD::BR_JT, MVT::Other, Expand); setOperationAction(ISD::BRIND, MVT::Other, Expand); setOperationAction(ISD::BR_CC, MVT::i8, Custom); setOperationAction(ISD::BR_CC, MVT::i16, Custom); setOperationAction(ISD::BRCOND, MVT::Other, Expand); setOperationAction(ISD::SETCC, MVT::i8, Expand); setOperationAction(ISD::SETCC, MVT::i16, Expand); setOperationAction(ISD::SELECT, MVT::i8, Expand); setOperationAction(ISD::SELECT, MVT::i16, Expand); setOperationAction(ISD::SELECT_CC, MVT::i8, Custom); setOperationAction(ISD::SELECT_CC, MVT::i16, Custom); setOperationAction(ISD::SIGN_EXTEND, MVT::i16, Custom); setOperationAction(ISD::CTTZ, MVT::i8, Expand); setOperationAction(ISD::CTTZ, MVT::i16, Expand); setOperationAction(ISD::CTLZ, MVT::i8, Expand); setOperationAction(ISD::CTLZ, MVT::i16, Expand); setOperationAction(ISD::CTPOP, MVT::i8, Expand); setOperationAction(ISD::CTPOP, MVT::i16, Expand); setOperationAction(ISD::SHL_PARTS, MVT::i8, Expand); setOperationAction(ISD::SHL_PARTS, MVT::i16, Expand); setOperationAction(ISD::SRL_PARTS, MVT::i8, Expand); setOperationAction(ISD::SRL_PARTS, MVT::i16, Expand); setOperationAction(ISD::SRA_PARTS, MVT::i8, Expand); setOperationAction(ISD::SRA_PARTS, MVT::i16, Expand); setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand); // FIXME: Implement efficiently multiplication by a constant setOperationAction(ISD::MUL, MVT::i16, Expand); setOperationAction(ISD::MULHS, MVT::i16, Expand); setOperationAction(ISD::MULHU, MVT::i16, Expand); setOperationAction(ISD::SMUL_LOHI, MVT::i16, Expand); setOperationAction(ISD::UMUL_LOHI, MVT::i16, Expand); setOperationAction(ISD::UDIV, MVT::i16, Expand); setOperationAction(ISD::UDIVREM, MVT::i16, Expand); setOperationAction(ISD::UREM, MVT::i16, Expand); setOperationAction(ISD::SDIV, MVT::i16, Expand); setOperationAction(ISD::SDIVREM, MVT::i16, Expand); setOperationAction(ISD::SREM, MVT::i16, Expand); } SDValue MSP430TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) { switch (Op.getOpcode()) { case ISD::SHL: // FALLTHROUGH case ISD::SRL: case ISD::SRA: return LowerShifts(Op, DAG); case ISD::GlobalAddress: return LowerGlobalAddress(Op, DAG); case ISD::ExternalSymbol: return LowerExternalSymbol(Op, DAG); case ISD::BR_CC: return LowerBR_CC(Op, DAG); case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG); case ISD::SIGN_EXTEND: return LowerSIGN_EXTEND(Op, DAG); default: llvm_unreachable("unimplemented operand"); return SDValue(); } } /// getFunctionAlignment - Return the Log2 alignment of this function. unsigned MSP430TargetLowering::getFunctionAlignment(const Function *F) const { return F->hasFnAttr(Attribute::OptimizeForSize) ? 1 : 4; } //===----------------------------------------------------------------------===// // Calling Convention Implementation //===----------------------------------------------------------------------===// #include "MSP430GenCallingConv.inc" SDValue MSP430TargetLowering::LowerFormalArguments(SDValue Chain, unsigned CallConv, bool isVarArg, const SmallVectorImpl &Ins, DebugLoc dl, SelectionDAG &DAG, SmallVectorImpl &InVals) { switch (CallConv) { default: llvm_unreachable("Unsupported calling convention"); case CallingConv::C: case CallingConv::Fast: return LowerCCCArguments(Chain, CallConv, isVarArg, Ins, dl, DAG, InVals); } } SDValue MSP430TargetLowering::LowerCall(SDValue Chain, SDValue Callee, unsigned CallConv, bool isVarArg, bool isTailCall, const SmallVectorImpl &Outs, const SmallVectorImpl &Ins, DebugLoc dl, SelectionDAG &DAG, SmallVectorImpl &InVals) { switch (CallConv) { default: llvm_unreachable("Unsupported calling convention"); case CallingConv::Fast: case CallingConv::C: return LowerCCCCallTo(Chain, Callee, CallConv, isVarArg, isTailCall, Outs, Ins, dl, DAG, InVals); } } /// LowerCCCArguments - transform physical registers into virtual registers and /// generate load operations for arguments places on the stack. // FIXME: struct return stuff // FIXME: varargs SDValue MSP430TargetLowering::LowerCCCArguments(SDValue Chain, unsigned CallConv, bool isVarArg, const SmallVectorImpl &Ins, DebugLoc dl, SelectionDAG &DAG, SmallVectorImpl &InVals) { MachineFunction &MF = DAG.getMachineFunction(); MachineFrameInfo *MFI = MF.getFrameInfo(); MachineRegisterInfo &RegInfo = MF.getRegInfo(); // Assign locations to all of the incoming arguments. SmallVector ArgLocs; CCState CCInfo(CallConv, isVarArg, getTargetMachine(), ArgLocs, *DAG.getContext()); CCInfo.AnalyzeFormalArguments(Ins, CC_MSP430); assert(!isVarArg && "Varargs not supported yet"); for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { CCValAssign &VA = ArgLocs[i]; if (VA.isRegLoc()) { // Arguments passed in registers MVT RegVT = VA.getLocVT(); switch (RegVT.getSimpleVT()) { default: { #ifndef NDEBUG cerr << "LowerFormalArguments Unhandled argument type: " << RegVT.getSimpleVT() << "\n"; #endif llvm_unreachable(0); } case MVT::i16: unsigned VReg = RegInfo.createVirtualRegister(MSP430::GR16RegisterClass); RegInfo.addLiveIn(VA.getLocReg(), VReg); SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, VReg, RegVT); // If this is an 8-bit value, it is really passed promoted to 16 // bits. Insert an assert[sz]ext to capture this, then truncate to the // right size. if (VA.getLocInfo() == CCValAssign::SExt) ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue, DAG.getValueType(VA.getValVT())); else if (VA.getLocInfo() == CCValAssign::ZExt) ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue, DAG.getValueType(VA.getValVT())); if (VA.getLocInfo() != CCValAssign::Full) ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue); InVals.push_back(ArgValue); } } else { // Sanity check assert(VA.isMemLoc()); // Load the argument to a virtual register unsigned ObjSize = VA.getLocVT().getSizeInBits()/8; if (ObjSize > 2) { cerr << "LowerFormalArguments Unhandled argument type: " << VA.getLocVT().getSimpleVT() << "\n"; } // Create the frame index object for this incoming parameter... int FI = MFI->CreateFixedObject(ObjSize, VA.getLocMemOffset()); // Create the SelectionDAG nodes corresponding to a load //from this parameter SDValue FIN = DAG.getFrameIndex(FI, MVT::i16); InVals.push_back(DAG.getLoad(VA.getLocVT(), dl, Chain, FIN, PseudoSourceValue::getFixedStack(FI), 0)); } } return Chain; } SDValue MSP430TargetLowering::LowerReturn(SDValue Chain, unsigned CallConv, bool isVarArg, const SmallVectorImpl &Outs, DebugLoc dl, SelectionDAG &DAG) { // CCValAssign - represent the assignment of the return value to a location SmallVector RVLocs; // CCState - Info about the registers and stack slot. CCState CCInfo(CallConv, isVarArg, getTargetMachine(), RVLocs, *DAG.getContext()); // Analize return values. CCInfo.AnalyzeReturn(Outs, RetCC_MSP430); // If this is the first return lowered for this function, add the regs to the // liveout set for the function. if (DAG.getMachineFunction().getRegInfo().liveout_empty()) { for (unsigned i = 0; i != RVLocs.size(); ++i) if (RVLocs[i].isRegLoc()) DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg()); } SDValue Flag; // Copy the result values into the output registers. for (unsigned i = 0; i != RVLocs.size(); ++i) { CCValAssign &VA = RVLocs[i]; assert(VA.isRegLoc() && "Can only return in registers!"); Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(), Outs[i].Val, Flag); // Guarantee that all emitted copies are stuck together, // avoiding something bad. Flag = Chain.getValue(1); } if (Flag.getNode()) return DAG.getNode(MSP430ISD::RET_FLAG, dl, MVT::Other, Chain, Flag); // Return Void return DAG.getNode(MSP430ISD::RET_FLAG, dl, MVT::Other, Chain); } /// LowerCCCCallTo - functions arguments are copied from virtual regs to /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted. /// TODO: sret. SDValue MSP430TargetLowering::LowerCCCCallTo(SDValue Chain, SDValue Callee, unsigned CallConv, bool isVarArg, bool isTailCall, const SmallVectorImpl &Outs, const SmallVectorImpl &Ins, DebugLoc dl, SelectionDAG &DAG, SmallVectorImpl &InVals) { // Analyze operands of the call, assigning locations to each operand. SmallVector ArgLocs; CCState CCInfo(CallConv, isVarArg, getTargetMachine(), ArgLocs, *DAG.getContext()); CCInfo.AnalyzeCallOperands(Outs, CC_MSP430); // Get a count of how many bytes are to be pushed on the stack. unsigned NumBytes = CCInfo.getNextStackOffset(); Chain = DAG.getCALLSEQ_START(Chain ,DAG.getConstant(NumBytes, getPointerTy(), true)); SmallVector, 4> RegsToPass; SmallVector MemOpChains; SDValue StackPtr; // Walk the register/memloc assignments, inserting copies/loads. for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { CCValAssign &VA = ArgLocs[i]; SDValue Arg = Outs[i].Val; // Promote the value if needed. switch (VA.getLocInfo()) { default: llvm_unreachable("Unknown loc info!"); case CCValAssign::Full: break; case CCValAssign::SExt: Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg); break; case CCValAssign::ZExt: Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg); break; case CCValAssign::AExt: Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg); break; } // Arguments that can be passed on register must be kept at RegsToPass // vector if (VA.isRegLoc()) { RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg)); } else { assert(VA.isMemLoc()); if (StackPtr.getNode() == 0) StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SPW, getPointerTy()); SDValue PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(), StackPtr, DAG.getIntPtrConstant(VA.getLocMemOffset())); MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff, PseudoSourceValue::getStack(), VA.getLocMemOffset())); } } // Transform all store nodes into one single node because all store nodes are // independent of each other. if (!MemOpChains.empty()) Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &MemOpChains[0], MemOpChains.size()); // Build a sequence of copy-to-reg nodes chained together with token chain and // flag operands which copy the outgoing args into registers. The InFlag in // necessary since all emited instructions must be stuck together. SDValue InFlag; for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) { Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first, RegsToPass[i].second, InFlag); InFlag = Chain.getValue(1); } // If the callee is a GlobalAddress node (quite common, every direct call is) // turn it into a TargetGlobalAddress node so that legalize doesn't hack it. // Likewise ExternalSymbol -> TargetExternalSymbol. if (GlobalAddressSDNode *G = dyn_cast(Callee)) Callee = DAG.getTargetGlobalAddress(G->getGlobal(), MVT::i16); else if (ExternalSymbolSDNode *E = dyn_cast(Callee)) Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16); // Returns a chain & a flag for retval copy to use. SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag); SmallVector Ops; Ops.push_back(Chain); Ops.push_back(Callee); // Add argument registers to the end of the list so that they are // known live into the call. for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) Ops.push_back(DAG.getRegister(RegsToPass[i].first, RegsToPass[i].second.getValueType())); if (InFlag.getNode()) Ops.push_back(InFlag); Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, &Ops[0], Ops.size()); InFlag = Chain.getValue(1); // Create the CALLSEQ_END node. Chain = DAG.getCALLSEQ_END(Chain, DAG.getConstant(NumBytes, getPointerTy(), true), DAG.getConstant(0, getPointerTy(), true), InFlag); InFlag = Chain.getValue(1); // Handle result values, copying them out of physregs into vregs that we // return. return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, dl, DAG, InVals); } /// LowerCallResult - Lower the result values of a call into the /// appropriate copies out of appropriate physical registers. /// SDValue MSP430TargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag, unsigned CallConv, bool isVarArg, const SmallVectorImpl &Ins, DebugLoc dl, SelectionDAG &DAG, SmallVectorImpl &InVals) { // Assign locations to each value returned by this call. SmallVector RVLocs; CCState CCInfo(CallConv, isVarArg, getTargetMachine(), RVLocs, *DAG.getContext()); CCInfo.AnalyzeCallResult(Ins, RetCC_MSP430); // Copy all of the result registers out of their specified physreg. for (unsigned i = 0; i != RVLocs.size(); ++i) { Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(), RVLocs[i].getValVT(), InFlag).getValue(1); InFlag = Chain.getValue(2); InVals.push_back(Chain.getValue(0)); } return Chain; } SDValue MSP430TargetLowering::LowerShifts(SDValue Op, SelectionDAG &DAG) { unsigned Opc = Op.getOpcode(); SDNode* N = Op.getNode(); MVT VT = Op.getValueType(); DebugLoc dl = N->getDebugLoc(); // We currently only lower shifts of constant argument. if (!isa(N->getOperand(1))) return SDValue(); uint64_t ShiftAmount = cast(N->getOperand(1))->getZExtValue(); // Expand the stuff into sequence of shifts. // FIXME: for some shift amounts this might be done better! // E.g.: foo >> (8 + N) => sxt(swpb(foo)) >> N SDValue Victim = N->getOperand(0); if (Opc == ISD::SRL && ShiftAmount) { // Emit a special goodness here: // srl A, 1 => clrc; rrc A Victim = DAG.getNode(MSP430ISD::RRC, dl, VT, Victim); ShiftAmount -= 1; } while (ShiftAmount--) Victim = DAG.getNode((Opc == ISD::SHL ? MSP430ISD::RLA : MSP430ISD::RRA), dl, VT, Victim); return Victim; } SDValue MSP430TargetLowering::LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) { const GlobalValue *GV = cast(Op)->getGlobal(); int64_t Offset = cast(Op)->getOffset(); // Create the TargetGlobalAddress node, folding in the constant offset. SDValue Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), Offset); return DAG.getNode(MSP430ISD::Wrapper, Op.getDebugLoc(), getPointerTy(), Result); } SDValue MSP430TargetLowering::LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) { DebugLoc dl = Op.getDebugLoc(); const char *Sym = cast(Op)->getSymbol(); SDValue Result = DAG.getTargetExternalSymbol(Sym, getPointerTy()); return DAG.getNode(MSP430ISD::Wrapper, dl, getPointerTy(), Result);; } static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, unsigned &TargetCC, ISD::CondCode CC, DebugLoc dl, SelectionDAG &DAG) { // FIXME: Handle bittests someday assert(!LHS.getValueType().isFloatingPoint() && "We don't handle FP yet"); // FIXME: Handle jump negative someday TargetCC = MSP430::COND_INVALID; switch (CC) { default: llvm_unreachable("Invalid integer condition!"); case ISD::SETEQ: TargetCC = MSP430::COND_E; // aka COND_Z break; case ISD::SETNE: TargetCC = MSP430::COND_NE; // aka COND_NZ break; case ISD::SETULE: std::swap(LHS, RHS); // FALLTHROUGH case ISD::SETUGE: TargetCC = MSP430::COND_HS; // aka COND_C break; case ISD::SETUGT: std::swap(LHS, RHS); // FALLTHROUGH case ISD::SETULT: TargetCC = MSP430::COND_LO; // aka COND_NC break; case ISD::SETLE: std::swap(LHS, RHS); // FALLTHROUGH case ISD::SETGE: TargetCC = MSP430::COND_GE; break; case ISD::SETGT: std::swap(LHS, RHS); // FALLTHROUGH case ISD::SETLT: TargetCC = MSP430::COND_L; break; } return DAG.getNode(MSP430ISD::CMP, dl, MVT::Flag, LHS, RHS); } SDValue MSP430TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) { SDValue Chain = Op.getOperand(0); ISD::CondCode CC = cast(Op.getOperand(1))->get(); SDValue LHS = Op.getOperand(2); SDValue RHS = Op.getOperand(3); SDValue Dest = Op.getOperand(4); DebugLoc dl = Op.getDebugLoc(); unsigned TargetCC = MSP430::COND_INVALID; SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG); return DAG.getNode(MSP430ISD::BR_CC, dl, Op.getValueType(), Chain, Dest, DAG.getConstant(TargetCC, MVT::i8), Flag); } SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) { SDValue LHS = Op.getOperand(0); SDValue RHS = Op.getOperand(1); SDValue TrueV = Op.getOperand(2); SDValue FalseV = Op.getOperand(3); ISD::CondCode CC = cast(Op.getOperand(4))->get(); DebugLoc dl = Op.getDebugLoc(); unsigned TargetCC = MSP430::COND_INVALID; SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG); SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Flag); SmallVector Ops; Ops.push_back(TrueV); Ops.push_back(FalseV); Ops.push_back(DAG.getConstant(TargetCC, MVT::i8)); Ops.push_back(Flag); return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, &Ops[0], Ops.size()); } SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op, SelectionDAG &DAG) { SDValue Val = Op.getOperand(0); MVT VT = Op.getValueType(); DebugLoc dl = Op.getDebugLoc(); assert(VT == MVT::i16 && "Only support i16 for now!"); return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT, DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val), DAG.getValueType(Val.getValueType())); } const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const { switch (Opcode) { default: return NULL; case MSP430ISD::RET_FLAG: return "MSP430ISD::RET_FLAG"; case MSP430ISD::RRA: return "MSP430ISD::RRA"; case MSP430ISD::RLA: return "MSP430ISD::RLA"; case MSP430ISD::RRC: return "MSP430ISD::RRC"; case MSP430ISD::CALL: return "MSP430ISD::CALL"; case MSP430ISD::Wrapper: return "MSP430ISD::Wrapper"; case MSP430ISD::BR_CC: return "MSP430ISD::BR_CC"; case MSP430ISD::CMP: return "MSP430ISD::CMP"; case MSP430ISD::SELECT_CC: return "MSP430ISD::SELECT_CC"; } } //===----------------------------------------------------------------------===// // Other Lowering Code //===----------------------------------------------------------------------===// MachineBasicBlock* MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI, MachineBasicBlock *BB) const { const TargetInstrInfo &TII = *getTargetMachine().getInstrInfo(); DebugLoc dl = MI->getDebugLoc(); assert((MI->getOpcode() == MSP430::Select16 || MI->getOpcode() == MSP430::Select8) && "Unexpected instr type to insert"); // To "insert" a SELECT instruction, we actually have to insert the diamond // control-flow pattern. The incoming instruction knows the destination vreg // to set, the condition code register to branch on, the true/false values to // select between, and a branch opcode to use. const BasicBlock *LLVM_BB = BB->getBasicBlock(); MachineFunction::iterator I = BB; ++I; // thisMBB: // ... // TrueVal = ... // cmpTY ccX, r1, r2 // jCC copy1MBB // fallthrough --> copy0MBB MachineBasicBlock *thisMBB = BB; MachineFunction *F = BB->getParent(); MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB); MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB); BuildMI(BB, dl, TII.get(MSP430::JCC)) .addMBB(copy1MBB) .addImm(MI->getOperand(3).getImm()); F->insert(I, copy0MBB); F->insert(I, copy1MBB); // Update machine-CFG edges by transferring all successors of the current // block to the new block which will contain the Phi node for the select. copy1MBB->transferSuccessors(BB); // Next, add the true and fallthrough blocks as its successors. BB->addSuccessor(copy0MBB); BB->addSuccessor(copy1MBB); // copy0MBB: // %FalseValue = ... // # fallthrough to copy1MBB BB = copy0MBB; // Update machine-CFG edges BB->addSuccessor(copy1MBB); // copy1MBB: // %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ] // ... BB = copy1MBB; BuildMI(BB, dl, TII.get(MSP430::PHI), MI->getOperand(0).getReg()) .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB) .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB); F->DeleteMachineInstr(MI); // The pseudo instruction is gone now. return BB; }