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      1 //===-- AlphaISelLowering.cpp - Alpha DAG Lowering Implementation ---------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file implements the AlphaISelLowering class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "AlphaISelLowering.h"
     15 #include "AlphaTargetMachine.h"
     16 #include "AlphaMachineFunctionInfo.h"
     17 #include "llvm/CodeGen/CallingConvLower.h"
     18 #include "llvm/CodeGen/MachineFrameInfo.h"
     19 #include "llvm/CodeGen/MachineFunction.h"
     20 #include "llvm/CodeGen/MachineInstrBuilder.h"
     21 #include "llvm/CodeGen/MachineRegisterInfo.h"
     22 #include "llvm/CodeGen/SelectionDAG.h"
     23 #include "llvm/CodeGen/MachineRegisterInfo.h"
     24 #include "llvm/CodeGen/PseudoSourceValue.h"
     25 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
     26 #include "llvm/Constants.h"
     27 #include "llvm/Function.h"
     28 #include "llvm/Module.h"
     29 #include "llvm/Intrinsics.h"
     30 #include "llvm/Type.h"
     31 #include "llvm/Support/CommandLine.h"
     32 #include "llvm/Support/ErrorHandling.h"
     33 #include "llvm/Support/raw_ostream.h"
     34 using namespace llvm;
     35 
     36 /// AddLiveIn - This helper function adds the specified physical register to the
     37 /// MachineFunction as a live in value.  It also creates a corresponding virtual
     38 /// register for it.
     39 static unsigned AddLiveIn(MachineFunction &MF, unsigned PReg,
     40                           TargetRegisterClass *RC) {
     41   assert(RC->contains(PReg) && "Not the correct regclass!");
     42   unsigned VReg = MF.getRegInfo().createVirtualRegister(RC);
     43   MF.getRegInfo().addLiveIn(PReg, VReg);
     44   return VReg;
     45 }
     46 
     47 AlphaTargetLowering::AlphaTargetLowering(TargetMachine &TM)
     48   : TargetLowering(TM, new TargetLoweringObjectFileELF()) {
     49   // Set up the TargetLowering object.
     50   //I am having problems with shr n i8 1
     51   setBooleanContents(ZeroOrOneBooleanContent);
     52   setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?
     53 
     54   addRegisterClass(MVT::i64, Alpha::GPRCRegisterClass);
     55   addRegisterClass(MVT::f64, Alpha::F8RCRegisterClass);
     56   addRegisterClass(MVT::f32, Alpha::F4RCRegisterClass);
     57 
     58   // We want to custom lower some of our intrinsics.
     59   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
     60 
     61   setLoadExtAction(ISD::EXTLOAD, MVT::i1,  Promote);
     62   setLoadExtAction(ISD::EXTLOAD, MVT::f32, Expand);
     63 
     64   setLoadExtAction(ISD::ZEXTLOAD, MVT::i1,  Promote);
     65   setLoadExtAction(ISD::ZEXTLOAD, MVT::i32, Expand);
     66 
     67   setLoadExtAction(ISD::SEXTLOAD, MVT::i1,  Promote);
     68   setLoadExtAction(ISD::SEXTLOAD, MVT::i8,  Expand);
     69   setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand);
     70 
     71   setTruncStoreAction(MVT::f64, MVT::f32, Expand);
     72 
     73   //  setOperationAction(ISD::BRIND,        MVT::Other,   Expand);
     74   setOperationAction(ISD::BR_JT,        MVT::Other, Expand);
     75   setOperationAction(ISD::BR_CC,        MVT::Other, Expand);
     76   setOperationAction(ISD::SELECT_CC,    MVT::Other, Expand);
     77 
     78   setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
     79 
     80   setOperationAction(ISD::FREM, MVT::f32, Expand);
     81   setOperationAction(ISD::FREM, MVT::f64, Expand);
     82 
     83   setOperationAction(ISD::UINT_TO_FP, MVT::i64, Expand);
     84   setOperationAction(ISD::SINT_TO_FP, MVT::i64, Custom);
     85   setOperationAction(ISD::FP_TO_UINT, MVT::i64, Expand);
     86   setOperationAction(ISD::FP_TO_SINT, MVT::i64, Custom);
     87 
     88   if (!TM.getSubtarget<AlphaSubtarget>().hasCT()) {
     89     setOperationAction(ISD::CTPOP    , MVT::i64  , Expand);
     90     setOperationAction(ISD::CTTZ     , MVT::i64  , Expand);
     91     setOperationAction(ISD::CTLZ     , MVT::i64  , Expand);
     92   }
     93   setOperationAction(ISD::BSWAP    , MVT::i64, Expand);
     94   setOperationAction(ISD::ROTL     , MVT::i64, Expand);
     95   setOperationAction(ISD::ROTR     , MVT::i64, Expand);
     96 
     97   setOperationAction(ISD::SREM     , MVT::i64, Custom);
     98   setOperationAction(ISD::UREM     , MVT::i64, Custom);
     99   setOperationAction(ISD::SDIV     , MVT::i64, Custom);
    100   setOperationAction(ISD::UDIV     , MVT::i64, Custom);
    101 
    102   setOperationAction(ISD::ADDC     , MVT::i64, Expand);
    103   setOperationAction(ISD::ADDE     , MVT::i64, Expand);
    104   setOperationAction(ISD::SUBC     , MVT::i64, Expand);
    105   setOperationAction(ISD::SUBE     , MVT::i64, Expand);
    106 
    107   setOperationAction(ISD::UMUL_LOHI, MVT::i64, Expand);
    108   setOperationAction(ISD::SMUL_LOHI, MVT::i64, Expand);
    109 
    110   setOperationAction(ISD::SRL_PARTS, MVT::i64, Custom);
    111   setOperationAction(ISD::SRA_PARTS, MVT::i64, Expand);
    112   setOperationAction(ISD::SHL_PARTS, MVT::i64, Expand);
    113 
    114   // We don't support sin/cos/sqrt/pow
    115   setOperationAction(ISD::FSIN , MVT::f64, Expand);
    116   setOperationAction(ISD::FCOS , MVT::f64, Expand);
    117   setOperationAction(ISD::FSIN , MVT::f32, Expand);
    118   setOperationAction(ISD::FCOS , MVT::f32, Expand);
    119 
    120   setOperationAction(ISD::FSQRT, MVT::f64, Expand);
    121   setOperationAction(ISD::FSQRT, MVT::f32, Expand);
    122 
    123   setOperationAction(ISD::FPOW , MVT::f32, Expand);
    124   setOperationAction(ISD::FPOW , MVT::f64, Expand);
    125 
    126   setOperationAction(ISD::FMA, MVT::f64, Expand);
    127   setOperationAction(ISD::FMA, MVT::f32, Expand);
    128 
    129   setOperationAction(ISD::SETCC, MVT::f32, Promote);
    130 
    131   setOperationAction(ISD::BITCAST, MVT::f32, Promote);
    132 
    133   setOperationAction(ISD::EH_LABEL, MVT::Other, Expand);
    134 
    135   // Not implemented yet.
    136   setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
    137   setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
    138   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64, Expand);
    139 
    140   // We want to legalize GlobalAddress and ConstantPool and
    141   // ExternalSymbols nodes into the appropriate instructions to
    142   // materialize the address.
    143   setOperationAction(ISD::GlobalAddress,  MVT::i64, Custom);
    144   setOperationAction(ISD::ConstantPool,   MVT::i64, Custom);
    145   setOperationAction(ISD::ExternalSymbol, MVT::i64, Custom);
    146   setOperationAction(ISD::GlobalTLSAddress, MVT::i64, Custom);
    147 
    148   setOperationAction(ISD::VASTART, MVT::Other, Custom);
    149   setOperationAction(ISD::VAEND,   MVT::Other, Expand);
    150   setOperationAction(ISD::VACOPY,  MVT::Other, Custom);
    151   setOperationAction(ISD::VAARG,   MVT::Other, Custom);
    152   setOperationAction(ISD::VAARG,   MVT::i32,   Custom);
    153 
    154   setOperationAction(ISD::JumpTable, MVT::i64, Custom);
    155   setOperationAction(ISD::JumpTable, MVT::i32, Custom);
    156 
    157   setOperationAction(ISD::ATOMIC_LOAD,  MVT::i32, Expand);
    158   setOperationAction(ISD::ATOMIC_STORE, MVT::i32, Expand);
    159 
    160   setStackPointerRegisterToSaveRestore(Alpha::R30);
    161 
    162   setJumpBufSize(272);
    163   setJumpBufAlignment(16);
    164 
    165   setMinFunctionAlignment(4);
    166 
    167   setInsertFencesForAtomic(true);
    168 
    169   computeRegisterProperties();
    170 }
    171 
    172 EVT AlphaTargetLowering::getSetCCResultType(EVT VT) const {
    173   return MVT::i64;
    174 }
    175 
    176 const char *AlphaTargetLowering::getTargetNodeName(unsigned Opcode) const {
    177   switch (Opcode) {
    178   default: return 0;
    179   case AlphaISD::CVTQT_: return "Alpha::CVTQT_";
    180   case AlphaISD::CVTQS_: return "Alpha::CVTQS_";
    181   case AlphaISD::CVTTQ_: return "Alpha::CVTTQ_";
    182   case AlphaISD::GPRelHi: return "Alpha::GPRelHi";
    183   case AlphaISD::GPRelLo: return "Alpha::GPRelLo";
    184   case AlphaISD::RelLit: return "Alpha::RelLit";
    185   case AlphaISD::GlobalRetAddr: return "Alpha::GlobalRetAddr";
    186   case AlphaISD::CALL:   return "Alpha::CALL";
    187   case AlphaISD::DivCall: return "Alpha::DivCall";
    188   case AlphaISD::RET_FLAG: return "Alpha::RET_FLAG";
    189   case AlphaISD::COND_BRANCH_I: return "Alpha::COND_BRANCH_I";
    190   case AlphaISD::COND_BRANCH_F: return "Alpha::COND_BRANCH_F";
    191   }
    192 }
    193 
    194 static SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) {
    195   EVT PtrVT = Op.getValueType();
    196   JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
    197   SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
    198   // FIXME there isn't really any debug info here
    199   DebugLoc dl = Op.getDebugLoc();
    200 
    201   SDValue Hi = DAG.getNode(AlphaISD::GPRelHi,  dl, MVT::i64, JTI,
    202                              DAG.getGLOBAL_OFFSET_TABLE(MVT::i64));
    203   SDValue Lo = DAG.getNode(AlphaISD::GPRelLo, dl, MVT::i64, JTI, Hi);
    204   return Lo;
    205 }
    206 
    207 //http://www.cs.arizona.edu/computer.help/policy/DIGITAL_unix/
    208 //AA-PY8AC-TET1_html/callCH3.html#BLOCK21
    209 
    210 //For now, just use variable size stack frame format
    211 
    212 //In a standard call, the first six items are passed in registers $16
    213 //- $21 and/or registers $f16 - $f21. (See Section 4.1.2 for details
    214 //of argument-to-register correspondence.) The remaining items are
    215 //collected in a memory argument list that is a naturally aligned
    216 //array of quadwords. In a standard call, this list, if present, must
    217 //be passed at 0(SP).
    218 //7 ... n         0(SP) ... (n-7)*8(SP)
    219 
    220 // //#define FP    $15
    221 // //#define RA    $26
    222 // //#define PV    $27
    223 // //#define GP    $29
    224 // //#define SP    $30
    225 
    226 #include "AlphaGenCallingConv.inc"
    227 
    228 SDValue
    229 AlphaTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
    230                                CallingConv::ID CallConv, bool isVarArg,
    231                                bool &isTailCall,
    232                                const SmallVectorImpl<ISD::OutputArg> &Outs,
    233                                const SmallVectorImpl<SDValue> &OutVals,
    234                                const SmallVectorImpl<ISD::InputArg> &Ins,
    235                                DebugLoc dl, SelectionDAG &DAG,
    236                                SmallVectorImpl<SDValue> &InVals) const {
    237   // Alpha target does not yet support tail call optimization.
    238   isTailCall = false;
    239 
    240   // Analyze operands of the call, assigning locations to each operand.
    241   SmallVector<CCValAssign, 16> ArgLocs;
    242   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
    243 		 getTargetMachine(), ArgLocs, *DAG.getContext());
    244 
    245   CCInfo.AnalyzeCallOperands(Outs, CC_Alpha);
    246 
    247     // Get a count of how many bytes are to be pushed on the stack.
    248   unsigned NumBytes = CCInfo.getNextStackOffset();
    249 
    250   Chain = DAG.getCALLSEQ_START(Chain, DAG.getConstant(NumBytes,
    251                                                       getPointerTy(), true));
    252 
    253   SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
    254   SmallVector<SDValue, 12> MemOpChains;
    255   SDValue StackPtr;
    256 
    257   // Walk the register/memloc assignments, inserting copies/loads.
    258   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
    259     CCValAssign &VA = ArgLocs[i];
    260 
    261     SDValue Arg = OutVals[i];
    262 
    263     // Promote the value if needed.
    264     switch (VA.getLocInfo()) {
    265       default: assert(0 && "Unknown loc info!");
    266       case CCValAssign::Full: break;
    267       case CCValAssign::SExt:
    268         Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
    269         break;
    270       case CCValAssign::ZExt:
    271         Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
    272         break;
    273       case CCValAssign::AExt:
    274         Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
    275         break;
    276     }
    277 
    278     // Arguments that can be passed on register must be kept at RegsToPass
    279     // vector
    280     if (VA.isRegLoc()) {
    281       RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
    282     } else {
    283       assert(VA.isMemLoc());
    284 
    285       if (StackPtr.getNode() == 0)
    286         StackPtr = DAG.getCopyFromReg(Chain, dl, Alpha::R30, MVT::i64);
    287 
    288       SDValue PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(),
    289                                    StackPtr,
    290                                    DAG.getIntPtrConstant(VA.getLocMemOffset()));
    291 
    292       MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
    293                                          MachinePointerInfo(),false, false, 0));
    294     }
    295   }
    296 
    297   // Transform all store nodes into one single node because all store nodes are
    298   // independent of each other.
    299   if (!MemOpChains.empty())
    300     Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
    301                         &MemOpChains[0], MemOpChains.size());
    302 
    303   // Build a sequence of copy-to-reg nodes chained together with token chain and
    304   // flag operands which copy the outgoing args into registers.  The InFlag in
    305   // necessary since all emitted instructions must be stuck together.
    306   SDValue InFlag;
    307   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
    308     Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
    309                              RegsToPass[i].second, InFlag);
    310     InFlag = Chain.getValue(1);
    311   }
    312 
    313   // Returns a chain & a flag for retval copy to use.
    314   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
    315   SmallVector<SDValue, 8> Ops;
    316   Ops.push_back(Chain);
    317   Ops.push_back(Callee);
    318 
    319   // Add argument registers to the end of the list so that they are
    320   // known live into the call.
    321   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
    322     Ops.push_back(DAG.getRegister(RegsToPass[i].first,
    323                                   RegsToPass[i].second.getValueType()));
    324 
    325   if (InFlag.getNode())
    326     Ops.push_back(InFlag);
    327 
    328   Chain = DAG.getNode(AlphaISD::CALL, dl, NodeTys, &Ops[0], Ops.size());
    329   InFlag = Chain.getValue(1);
    330 
    331   // Create the CALLSEQ_END node.
    332   Chain = DAG.getCALLSEQ_END(Chain,
    333                              DAG.getConstant(NumBytes, getPointerTy(), true),
    334                              DAG.getConstant(0, getPointerTy(), true),
    335                              InFlag);
    336   InFlag = Chain.getValue(1);
    337 
    338   // Handle result values, copying them out of physregs into vregs that we
    339   // return.
    340   return LowerCallResult(Chain, InFlag, CallConv, isVarArg,
    341                          Ins, dl, DAG, InVals);
    342 }
    343 
    344 /// LowerCallResult - Lower the result values of a call into the
    345 /// appropriate copies out of appropriate physical registers.
    346 ///
    347 SDValue
    348 AlphaTargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
    349                                      CallingConv::ID CallConv, bool isVarArg,
    350                                      const SmallVectorImpl<ISD::InputArg> &Ins,
    351                                      DebugLoc dl, SelectionDAG &DAG,
    352                                      SmallVectorImpl<SDValue> &InVals) const {
    353 
    354   // Assign locations to each value returned by this call.
    355   SmallVector<CCValAssign, 16> RVLocs;
    356   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
    357 		 getTargetMachine(), RVLocs, *DAG.getContext());
    358 
    359   CCInfo.AnalyzeCallResult(Ins, RetCC_Alpha);
    360 
    361   // Copy all of the result registers out of their specified physreg.
    362   for (unsigned i = 0; i != RVLocs.size(); ++i) {
    363     CCValAssign &VA = RVLocs[i];
    364 
    365     Chain = DAG.getCopyFromReg(Chain, dl, VA.getLocReg(),
    366                                VA.getLocVT(), InFlag).getValue(1);
    367     SDValue RetValue = Chain.getValue(0);
    368     InFlag = Chain.getValue(2);
    369 
    370     // If this is an 8/16/32-bit value, it is really passed promoted to 64
    371     // bits. Insert an assert[sz]ext to capture this, then truncate to the
    372     // right size.
    373     if (VA.getLocInfo() == CCValAssign::SExt)
    374       RetValue = DAG.getNode(ISD::AssertSext, dl, VA.getLocVT(), RetValue,
    375                              DAG.getValueType(VA.getValVT()));
    376     else if (VA.getLocInfo() == CCValAssign::ZExt)
    377       RetValue = DAG.getNode(ISD::AssertZext, dl, VA.getLocVT(), RetValue,
    378                              DAG.getValueType(VA.getValVT()));
    379 
    380     if (VA.getLocInfo() != CCValAssign::Full)
    381       RetValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), RetValue);
    382 
    383     InVals.push_back(RetValue);
    384   }
    385 
    386   return Chain;
    387 }
    388 
    389 SDValue
    390 AlphaTargetLowering::LowerFormalArguments(SDValue Chain,
    391                                           CallingConv::ID CallConv, bool isVarArg,
    392                                           const SmallVectorImpl<ISD::InputArg>
    393                                             &Ins,
    394                                           DebugLoc dl, SelectionDAG &DAG,
    395                                           SmallVectorImpl<SDValue> &InVals)
    396                                             const {
    397 
    398   MachineFunction &MF = DAG.getMachineFunction();
    399   MachineFrameInfo *MFI = MF.getFrameInfo();
    400   AlphaMachineFunctionInfo *FuncInfo = MF.getInfo<AlphaMachineFunctionInfo>();
    401 
    402   unsigned args_int[] = {
    403     Alpha::R16, Alpha::R17, Alpha::R18, Alpha::R19, Alpha::R20, Alpha::R21};
    404   unsigned args_float[] = {
    405     Alpha::F16, Alpha::F17, Alpha::F18, Alpha::F19, Alpha::F20, Alpha::F21};
    406 
    407   for (unsigned ArgNo = 0, e = Ins.size(); ArgNo != e; ++ArgNo) {
    408     SDValue argt;
    409     EVT ObjectVT = Ins[ArgNo].VT;
    410     SDValue ArgVal;
    411 
    412     if (ArgNo  < 6) {
    413       switch (ObjectVT.getSimpleVT().SimpleTy) {
    414       default:
    415         assert(false && "Invalid value type!");
    416       case MVT::f64:
    417         args_float[ArgNo] = AddLiveIn(MF, args_float[ArgNo],
    418                                       &Alpha::F8RCRegClass);
    419         ArgVal = DAG.getCopyFromReg(Chain, dl, args_float[ArgNo], ObjectVT);
    420         break;
    421       case MVT::f32:
    422         args_float[ArgNo] = AddLiveIn(MF, args_float[ArgNo],
    423                                       &Alpha::F4RCRegClass);
    424         ArgVal = DAG.getCopyFromReg(Chain, dl, args_float[ArgNo], ObjectVT);
    425         break;
    426       case MVT::i64:
    427         args_int[ArgNo] = AddLiveIn(MF, args_int[ArgNo],
    428                                     &Alpha::GPRCRegClass);
    429         ArgVal = DAG.getCopyFromReg(Chain, dl, args_int[ArgNo], MVT::i64);
    430         break;
    431       }
    432     } else { //more args
    433       // Create the frame index object for this incoming parameter...
    434       int FI = MFI->CreateFixedObject(8, 8 * (ArgNo - 6), true);
    435 
    436       // Create the SelectionDAG nodes corresponding to a load
    437       //from this parameter
    438       SDValue FIN = DAG.getFrameIndex(FI, MVT::i64);
    439       ArgVal = DAG.getLoad(ObjectVT, dl, Chain, FIN, MachinePointerInfo(),
    440                            false, false, 0);
    441     }
    442     InVals.push_back(ArgVal);
    443   }
    444 
    445   // If the functions takes variable number of arguments, copy all regs to stack
    446   if (isVarArg) {
    447     FuncInfo->setVarArgsOffset(Ins.size() * 8);
    448     std::vector<SDValue> LS;
    449     for (int i = 0; i < 6; ++i) {
    450       if (TargetRegisterInfo::isPhysicalRegister(args_int[i]))
    451         args_int[i] = AddLiveIn(MF, args_int[i], &Alpha::GPRCRegClass);
    452       SDValue argt = DAG.getCopyFromReg(Chain, dl, args_int[i], MVT::i64);
    453       int FI = MFI->CreateFixedObject(8, -8 * (6 - i), true);
    454       if (i == 0) FuncInfo->setVarArgsBase(FI);
    455       SDValue SDFI = DAG.getFrameIndex(FI, MVT::i64);
    456       LS.push_back(DAG.getStore(Chain, dl, argt, SDFI, MachinePointerInfo(),
    457                                 false, false, 0));
    458 
    459       if (TargetRegisterInfo::isPhysicalRegister(args_float[i]))
    460         args_float[i] = AddLiveIn(MF, args_float[i], &Alpha::F8RCRegClass);
    461       argt = DAG.getCopyFromReg(Chain, dl, args_float[i], MVT::f64);
    462       FI = MFI->CreateFixedObject(8, - 8 * (12 - i), true);
    463       SDFI = DAG.getFrameIndex(FI, MVT::i64);
    464       LS.push_back(DAG.getStore(Chain, dl, argt, SDFI, MachinePointerInfo(),
    465                                 false, false, 0));
    466     }
    467 
    468     //Set up a token factor with all the stack traffic
    469     Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &LS[0], LS.size());
    470   }
    471 
    472   return Chain;
    473 }
    474 
    475 SDValue
    476 AlphaTargetLowering::LowerReturn(SDValue Chain,
    477                                  CallingConv::ID CallConv, bool isVarArg,
    478                                  const SmallVectorImpl<ISD::OutputArg> &Outs,
    479                                  const SmallVectorImpl<SDValue> &OutVals,
    480                                  DebugLoc dl, SelectionDAG &DAG) const {
    481 
    482   SDValue Copy = DAG.getCopyToReg(Chain, dl, Alpha::R26,
    483                                   DAG.getNode(AlphaISD::GlobalRetAddr,
    484                                               DebugLoc(), MVT::i64),
    485                                   SDValue());
    486   switch (Outs.size()) {
    487   default:
    488     llvm_unreachable("Do not know how to return this many arguments!");
    489   case 0:
    490     break;
    491     //return SDValue(); // ret void is legal
    492   case 1: {
    493     EVT ArgVT = Outs[0].VT;
    494     unsigned ArgReg;
    495     if (ArgVT.isInteger())
    496       ArgReg = Alpha::R0;
    497     else {
    498       assert(ArgVT.isFloatingPoint());
    499       ArgReg = Alpha::F0;
    500     }
    501     Copy = DAG.getCopyToReg(Copy, dl, ArgReg,
    502                             OutVals[0], Copy.getValue(1));
    503     if (DAG.getMachineFunction().getRegInfo().liveout_empty())
    504       DAG.getMachineFunction().getRegInfo().addLiveOut(ArgReg);
    505     break;
    506   }
    507   case 2: {
    508     EVT ArgVT = Outs[0].VT;
    509     unsigned ArgReg1, ArgReg2;
    510     if (ArgVT.isInteger()) {
    511       ArgReg1 = Alpha::R0;
    512       ArgReg2 = Alpha::R1;
    513     } else {
    514       assert(ArgVT.isFloatingPoint());
    515       ArgReg1 = Alpha::F0;
    516       ArgReg2 = Alpha::F1;
    517     }
    518     Copy = DAG.getCopyToReg(Copy, dl, ArgReg1,
    519                             OutVals[0], Copy.getValue(1));
    520     if (std::find(DAG.getMachineFunction().getRegInfo().liveout_begin(),
    521                   DAG.getMachineFunction().getRegInfo().liveout_end(), ArgReg1)
    522         == DAG.getMachineFunction().getRegInfo().liveout_end())
    523       DAG.getMachineFunction().getRegInfo().addLiveOut(ArgReg1);
    524     Copy = DAG.getCopyToReg(Copy, dl, ArgReg2,
    525                             OutVals[1], Copy.getValue(1));
    526     if (std::find(DAG.getMachineFunction().getRegInfo().liveout_begin(),
    527                    DAG.getMachineFunction().getRegInfo().liveout_end(), ArgReg2)
    528         == DAG.getMachineFunction().getRegInfo().liveout_end())
    529       DAG.getMachineFunction().getRegInfo().addLiveOut(ArgReg2);
    530     break;
    531   }
    532   }
    533   return DAG.getNode(AlphaISD::RET_FLAG, dl,
    534                      MVT::Other, Copy, Copy.getValue(1));
    535 }
    536 
    537 void AlphaTargetLowering::LowerVAARG(SDNode *N, SDValue &Chain,
    538                                      SDValue &DataPtr,
    539                                      SelectionDAG &DAG) const {
    540   Chain = N->getOperand(0);
    541   SDValue VAListP = N->getOperand(1);
    542   const Value *VAListS = cast<SrcValueSDNode>(N->getOperand(2))->getValue();
    543   DebugLoc dl = N->getDebugLoc();
    544 
    545   SDValue Base = DAG.getLoad(MVT::i64, dl, Chain, VAListP,
    546                              MachinePointerInfo(VAListS),
    547                              false, false, 0);
    548   SDValue Tmp = DAG.getNode(ISD::ADD, dl, MVT::i64, VAListP,
    549                               DAG.getConstant(8, MVT::i64));
    550   SDValue Offset = DAG.getExtLoad(ISD::SEXTLOAD, dl, MVT::i64, Base.getValue(1),
    551                                   Tmp, MachinePointerInfo(),
    552                                   MVT::i32, false, false, 0);
    553   DataPtr = DAG.getNode(ISD::ADD, dl, MVT::i64, Base, Offset);
    554   if (N->getValueType(0).isFloatingPoint())
    555   {
    556     //if fp && Offset < 6*8, then subtract 6*8 from DataPtr
    557     SDValue FPDataPtr = DAG.getNode(ISD::SUB, dl, MVT::i64, DataPtr,
    558                                       DAG.getConstant(8*6, MVT::i64));
    559     SDValue CC = DAG.getSetCC(dl, MVT::i64, Offset,
    560                                 DAG.getConstant(8*6, MVT::i64), ISD::SETLT);
    561     DataPtr = DAG.getNode(ISD::SELECT, dl, MVT::i64, CC, FPDataPtr, DataPtr);
    562   }
    563 
    564   SDValue NewOffset = DAG.getNode(ISD::ADD, dl, MVT::i64, Offset,
    565                                     DAG.getConstant(8, MVT::i64));
    566   Chain = DAG.getTruncStore(Offset.getValue(1), dl, NewOffset, Tmp,
    567                             MachinePointerInfo(),
    568                             MVT::i32, false, false, 0);
    569 }
    570 
    571 /// LowerOperation - Provide custom lowering hooks for some operations.
    572 ///
    573 SDValue AlphaTargetLowering::LowerOperation(SDValue Op,
    574                                             SelectionDAG &DAG) const {
    575   DebugLoc dl = Op.getDebugLoc();
    576   switch (Op.getOpcode()) {
    577   default: llvm_unreachable("Wasn't expecting to be able to lower this!");
    578   case ISD::JumpTable: return LowerJumpTable(Op, DAG);
    579 
    580   case ISD::INTRINSIC_WO_CHAIN: {
    581     unsigned IntNo = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
    582     switch (IntNo) {
    583     default: break;    // Don't custom lower most intrinsics.
    584     case Intrinsic::alpha_umulh:
    585       return DAG.getNode(ISD::MULHU, dl, MVT::i64,
    586                          Op.getOperand(1), Op.getOperand(2));
    587     }
    588   }
    589 
    590   case ISD::SRL_PARTS: {
    591     SDValue ShOpLo = Op.getOperand(0);
    592     SDValue ShOpHi = Op.getOperand(1);
    593     SDValue ShAmt  = Op.getOperand(2);
    594     SDValue bm = DAG.getNode(ISD::SUB, dl, MVT::i64,
    595                              DAG.getConstant(64, MVT::i64), ShAmt);
    596     SDValue BMCC = DAG.getSetCC(dl, MVT::i64, bm,
    597                                 DAG.getConstant(0, MVT::i64), ISD::SETLE);
    598     // if 64 - shAmt <= 0
    599     SDValue Hi_Neg = DAG.getConstant(0, MVT::i64);
    600     SDValue ShAmt_Neg = DAG.getNode(ISD::SUB, dl, MVT::i64,
    601                                     DAG.getConstant(0, MVT::i64), bm);
    602     SDValue Lo_Neg = DAG.getNode(ISD::SRL, dl, MVT::i64, ShOpHi, ShAmt_Neg);
    603     // else
    604     SDValue carries = DAG.getNode(ISD::SHL, dl, MVT::i64, ShOpHi, bm);
    605     SDValue Hi_Pos =  DAG.getNode(ISD::SRL, dl, MVT::i64, ShOpHi, ShAmt);
    606     SDValue Lo_Pos = DAG.getNode(ISD::SRL, dl, MVT::i64, ShOpLo, ShAmt);
    607     Lo_Pos = DAG.getNode(ISD::OR, dl, MVT::i64, Lo_Pos, carries);
    608     // Merge
    609     SDValue Hi = DAG.getNode(ISD::SELECT, dl, MVT::i64, BMCC, Hi_Neg, Hi_Pos);
    610     SDValue Lo = DAG.getNode(ISD::SELECT, dl, MVT::i64, BMCC, Lo_Neg, Lo_Pos);
    611     SDValue Ops[2] = { Lo, Hi };
    612     return DAG.getMergeValues(Ops, 2, dl);
    613   }
    614     //  case ISD::SRA_PARTS:
    615 
    616     //  case ISD::SHL_PARTS:
    617 
    618 
    619   case ISD::SINT_TO_FP: {
    620     assert(Op.getOperand(0).getValueType() == MVT::i64 &&
    621            "Unhandled SINT_TO_FP type in custom expander!");
    622     SDValue LD;
    623     bool isDouble = Op.getValueType() == MVT::f64;
    624     LD = DAG.getNode(ISD::BITCAST, dl, MVT::f64, Op.getOperand(0));
    625     SDValue FP = DAG.getNode(isDouble?AlphaISD::CVTQT_:AlphaISD::CVTQS_, dl,
    626                                isDouble?MVT::f64:MVT::f32, LD);
    627     return FP;
    628   }
    629   case ISD::FP_TO_SINT: {
    630     bool isDouble = Op.getOperand(0).getValueType() == MVT::f64;
    631     SDValue src = Op.getOperand(0);
    632 
    633     if (!isDouble) //Promote
    634       src = DAG.getNode(ISD::FP_EXTEND, dl, MVT::f64, src);
    635 
    636     src = DAG.getNode(AlphaISD::CVTTQ_, dl, MVT::f64, src);
    637 
    638     return DAG.getNode(ISD::BITCAST, dl, MVT::i64, src);
    639   }
    640   case ISD::ConstantPool: {
    641     ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
    642     const Constant *C = CP->getConstVal();
    643     SDValue CPI = DAG.getTargetConstantPool(C, MVT::i64, CP->getAlignment());
    644     // FIXME there isn't really any debug info here
    645 
    646     SDValue Hi = DAG.getNode(AlphaISD::GPRelHi,  dl, MVT::i64, CPI,
    647                                DAG.getGLOBAL_OFFSET_TABLE(MVT::i64));
    648     SDValue Lo = DAG.getNode(AlphaISD::GPRelLo, dl, MVT::i64, CPI, Hi);
    649     return Lo;
    650   }
    651   case ISD::GlobalTLSAddress:
    652     llvm_unreachable("TLS not implemented for Alpha.");
    653   case ISD::GlobalAddress: {
    654     GlobalAddressSDNode *GSDN = cast<GlobalAddressSDNode>(Op);
    655     const GlobalValue *GV = GSDN->getGlobal();
    656     SDValue GA = DAG.getTargetGlobalAddress(GV, dl, MVT::i64,
    657                                             GSDN->getOffset());
    658     // FIXME there isn't really any debug info here
    659 
    660     //    if (!GV->hasWeakLinkage() && !GV->isDeclaration()
    661     //        && !GV->hasLinkOnceLinkage()) {
    662     if (GV->hasLocalLinkage()) {
    663       SDValue Hi = DAG.getNode(AlphaISD::GPRelHi,  dl, MVT::i64, GA,
    664                                 DAG.getGLOBAL_OFFSET_TABLE(MVT::i64));
    665       SDValue Lo = DAG.getNode(AlphaISD::GPRelLo, dl, MVT::i64, GA, Hi);
    666       return Lo;
    667     } else
    668       return DAG.getNode(AlphaISD::RelLit, dl, MVT::i64, GA,
    669                          DAG.getGLOBAL_OFFSET_TABLE(MVT::i64));
    670   }
    671   case ISD::ExternalSymbol: {
    672     return DAG.getNode(AlphaISD::RelLit, dl, MVT::i64,
    673                        DAG.getTargetExternalSymbol(cast<ExternalSymbolSDNode>(Op)
    674                                                    ->getSymbol(), MVT::i64),
    675                        DAG.getGLOBAL_OFFSET_TABLE(MVT::i64));
    676   }
    677 
    678   case ISD::UREM:
    679   case ISD::SREM:
    680     //Expand only on constant case
    681     if (Op.getOperand(1).getOpcode() == ISD::Constant) {
    682       EVT VT = Op.getNode()->getValueType(0);
    683       SDValue Tmp1 = Op.getNode()->getOpcode() == ISD::UREM ?
    684         BuildUDIV(Op.getNode(), DAG, NULL) :
    685         BuildSDIV(Op.getNode(), DAG, NULL);
    686       Tmp1 = DAG.getNode(ISD::MUL, dl, VT, Tmp1, Op.getOperand(1));
    687       Tmp1 = DAG.getNode(ISD::SUB, dl, VT, Op.getOperand(0), Tmp1);
    688       return Tmp1;
    689     }
    690     //fall through
    691   case ISD::SDIV:
    692   case ISD::UDIV:
    693     if (Op.getValueType().isInteger()) {
    694       if (Op.getOperand(1).getOpcode() == ISD::Constant)
    695         return Op.getOpcode() == ISD::SDIV ? BuildSDIV(Op.getNode(), DAG, NULL)
    696           : BuildUDIV(Op.getNode(), DAG, NULL);
    697       const char* opstr = 0;
    698       switch (Op.getOpcode()) {
    699       case ISD::UREM: opstr = "__remqu"; break;
    700       case ISD::SREM: opstr = "__remq";  break;
    701       case ISD::UDIV: opstr = "__divqu"; break;
    702       case ISD::SDIV: opstr = "__divq";  break;
    703       }
    704       SDValue Tmp1 = Op.getOperand(0),
    705         Tmp2 = Op.getOperand(1),
    706         Addr = DAG.getExternalSymbol(opstr, MVT::i64);
    707       return DAG.getNode(AlphaISD::DivCall, dl, MVT::i64, Addr, Tmp1, Tmp2);
    708     }
    709     break;
    710 
    711   case ISD::VAARG: {
    712     SDValue Chain, DataPtr;
    713     LowerVAARG(Op.getNode(), Chain, DataPtr, DAG);
    714 
    715     SDValue Result;
    716     if (Op.getValueType() == MVT::i32)
    717       Result = DAG.getExtLoad(ISD::SEXTLOAD, dl, MVT::i64, Chain, DataPtr,
    718                               MachinePointerInfo(), MVT::i32, false, false, 0);
    719     else
    720       Result = DAG.getLoad(Op.getValueType(), dl, Chain, DataPtr,
    721                            MachinePointerInfo(),
    722                            false, false, 0);
    723     return Result;
    724   }
    725   case ISD::VACOPY: {
    726     SDValue Chain = Op.getOperand(0);
    727     SDValue DestP = Op.getOperand(1);
    728     SDValue SrcP = Op.getOperand(2);
    729     const Value *DestS = cast<SrcValueSDNode>(Op.getOperand(3))->getValue();
    730     const Value *SrcS = cast<SrcValueSDNode>(Op.getOperand(4))->getValue();
    731 
    732     SDValue Val = DAG.getLoad(getPointerTy(), dl, Chain, SrcP,
    733                               MachinePointerInfo(SrcS),
    734                               false, false, 0);
    735     SDValue Result = DAG.getStore(Val.getValue(1), dl, Val, DestP,
    736                                   MachinePointerInfo(DestS),
    737                                   false, false, 0);
    738     SDValue NP = DAG.getNode(ISD::ADD, dl, MVT::i64, SrcP,
    739                                DAG.getConstant(8, MVT::i64));
    740     Val = DAG.getExtLoad(ISD::SEXTLOAD, dl, MVT::i64, Result,
    741                          NP, MachinePointerInfo(), MVT::i32, false, false, 0);
    742     SDValue NPD = DAG.getNode(ISD::ADD, dl, MVT::i64, DestP,
    743                                 DAG.getConstant(8, MVT::i64));
    744     return DAG.getTruncStore(Val.getValue(1), dl, Val, NPD,
    745                              MachinePointerInfo(), MVT::i32,
    746                              false, false, 0);
    747   }
    748   case ISD::VASTART: {
    749     MachineFunction &MF = DAG.getMachineFunction();
    750     AlphaMachineFunctionInfo *FuncInfo = MF.getInfo<AlphaMachineFunctionInfo>();
    751 
    752     SDValue Chain = Op.getOperand(0);
    753     SDValue VAListP = Op.getOperand(1);
    754     const Value *VAListS = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
    755 
    756     // vastart stores the address of the VarArgsBase and VarArgsOffset
    757     SDValue FR  = DAG.getFrameIndex(FuncInfo->getVarArgsBase(), MVT::i64);
    758     SDValue S1  = DAG.getStore(Chain, dl, FR, VAListP,
    759                                MachinePointerInfo(VAListS), false, false, 0);
    760     SDValue SA2 = DAG.getNode(ISD::ADD, dl, MVT::i64, VAListP,
    761                                 DAG.getConstant(8, MVT::i64));
    762     return DAG.getTruncStore(S1, dl,
    763                              DAG.getConstant(FuncInfo->getVarArgsOffset(),
    764                                              MVT::i64),
    765                              SA2, MachinePointerInfo(),
    766                              MVT::i32, false, false, 0);
    767   }
    768   case ISD::RETURNADDR:
    769     return DAG.getNode(AlphaISD::GlobalRetAddr, DebugLoc(), MVT::i64);
    770       //FIXME: implement
    771   case ISD::FRAMEADDR:          break;
    772   }
    773 
    774   return SDValue();
    775 }
    776 
    777 void AlphaTargetLowering::ReplaceNodeResults(SDNode *N,
    778                                              SmallVectorImpl<SDValue>&Results,
    779                                              SelectionDAG &DAG) const {
    780   DebugLoc dl = N->getDebugLoc();
    781   assert(N->getValueType(0) == MVT::i32 &&
    782          N->getOpcode() == ISD::VAARG &&
    783          "Unknown node to custom promote!");
    784 
    785   SDValue Chain, DataPtr;
    786   LowerVAARG(N, Chain, DataPtr, DAG);
    787   SDValue Res = DAG.getLoad(N->getValueType(0), dl, Chain, DataPtr,
    788                             MachinePointerInfo(),
    789                             false, false, 0);
    790   Results.push_back(Res);
    791   Results.push_back(SDValue(Res.getNode(), 1));
    792 }
    793 
    794 
    795 //Inline Asm
    796 
    797 /// getConstraintType - Given a constraint letter, return the type of
    798 /// constraint it is for this target.
    799 AlphaTargetLowering::ConstraintType
    800 AlphaTargetLowering::getConstraintType(const std::string &Constraint) const {
    801   if (Constraint.size() == 1) {
    802     switch (Constraint[0]) {
    803     default: break;
    804     case 'f':
    805     case 'r':
    806       return C_RegisterClass;
    807     }
    808   }
    809   return TargetLowering::getConstraintType(Constraint);
    810 }
    811 
    812 /// Examine constraint type and operand type and determine a weight value.
    813 /// This object must already have been set up with the operand type
    814 /// and the current alternative constraint selected.
    815 TargetLowering::ConstraintWeight
    816 AlphaTargetLowering::getSingleConstraintMatchWeight(
    817     AsmOperandInfo &info, const char *constraint) const {
    818   ConstraintWeight weight = CW_Invalid;
    819   Value *CallOperandVal = info.CallOperandVal;
    820     // If we don't have a value, we can't do a match,
    821     // but allow it at the lowest weight.
    822   if (CallOperandVal == NULL)
    823     return CW_Default;
    824   // Look at the constraint type.
    825   switch (*constraint) {
    826   default:
    827     weight = TargetLowering::getSingleConstraintMatchWeight(info, constraint);
    828     break;
    829   case 'f':
    830     weight = CW_Register;
    831     break;
    832   }
    833   return weight;
    834 }
    835 
    836 /// Given a register class constraint, like 'r', if this corresponds directly
    837 /// to an LLVM register class, return a register of 0 and the register class
    838 /// pointer.
    839 std::pair<unsigned, const TargetRegisterClass*> AlphaTargetLowering::
    840 getRegForInlineAsmConstraint(const std::string &Constraint, EVT VT) const
    841 {
    842   if (Constraint.size() == 1) {
    843     switch (Constraint[0]) {
    844     case 'r':
    845       return std::make_pair(0U, Alpha::GPRCRegisterClass);
    846     case 'f':
    847       return VT == MVT::f64 ? std::make_pair(0U, Alpha::F8RCRegisterClass) :
    848 	std::make_pair(0U, Alpha::F4RCRegisterClass);
    849     }
    850   }
    851   return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
    852 }
    853 
    854 //===----------------------------------------------------------------------===//
    855 //  Other Lowering Code
    856 //===----------------------------------------------------------------------===//
    857 
    858 MachineBasicBlock *
    859 AlphaTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
    860                                                  MachineBasicBlock *BB) const {
    861   const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
    862   assert((MI->getOpcode() == Alpha::CAS32 ||
    863           MI->getOpcode() == Alpha::CAS64 ||
    864           MI->getOpcode() == Alpha::LAS32 ||
    865           MI->getOpcode() == Alpha::LAS64 ||
    866           MI->getOpcode() == Alpha::SWAP32 ||
    867           MI->getOpcode() == Alpha::SWAP64) &&
    868          "Unexpected instr type to insert");
    869 
    870   bool is32 = MI->getOpcode() == Alpha::CAS32 ||
    871     MI->getOpcode() == Alpha::LAS32 ||
    872     MI->getOpcode() == Alpha::SWAP32;
    873 
    874   //Load locked store conditional for atomic ops take on the same form
    875   //start:
    876   //ll
    877   //do stuff (maybe branch to exit)
    878   //sc
    879   //test sc and maybe branck to start
    880   //exit:
    881   const BasicBlock *LLVM_BB = BB->getBasicBlock();
    882   DebugLoc dl = MI->getDebugLoc();
    883   MachineFunction::iterator It = BB;
    884   ++It;
    885 
    886   MachineBasicBlock *thisMBB = BB;
    887   MachineFunction *F = BB->getParent();
    888   MachineBasicBlock *llscMBB = F->CreateMachineBasicBlock(LLVM_BB);
    889   MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB);
    890 
    891   sinkMBB->splice(sinkMBB->begin(), thisMBB,
    892                   llvm::next(MachineBasicBlock::iterator(MI)),
    893                   thisMBB->end());
    894   sinkMBB->transferSuccessorsAndUpdatePHIs(thisMBB);
    895 
    896   F->insert(It, llscMBB);
    897   F->insert(It, sinkMBB);
    898 
    899   BuildMI(thisMBB, dl, TII->get(Alpha::BR)).addMBB(llscMBB);
    900 
    901   unsigned reg_res = MI->getOperand(0).getReg(),
    902     reg_ptr = MI->getOperand(1).getReg(),
    903     reg_v2 = MI->getOperand(2).getReg(),
    904     reg_store = F->getRegInfo().createVirtualRegister(&Alpha::GPRCRegClass);
    905 
    906   BuildMI(llscMBB, dl, TII->get(is32 ? Alpha::LDL_L : Alpha::LDQ_L),
    907           reg_res).addImm(0).addReg(reg_ptr);
    908   switch (MI->getOpcode()) {
    909   case Alpha::CAS32:
    910   case Alpha::CAS64: {
    911     unsigned reg_cmp
    912       = F->getRegInfo().createVirtualRegister(&Alpha::GPRCRegClass);
    913     BuildMI(llscMBB, dl, TII->get(Alpha::CMPEQ), reg_cmp)
    914       .addReg(reg_v2).addReg(reg_res);
    915     BuildMI(llscMBB, dl, TII->get(Alpha::BEQ))
    916       .addImm(0).addReg(reg_cmp).addMBB(sinkMBB);
    917     BuildMI(llscMBB, dl, TII->get(Alpha::BISr), reg_store)
    918       .addReg(Alpha::R31).addReg(MI->getOperand(3).getReg());
    919     break;
    920   }
    921   case Alpha::LAS32:
    922   case Alpha::LAS64: {
    923     BuildMI(llscMBB, dl,TII->get(is32 ? Alpha::ADDLr : Alpha::ADDQr), reg_store)
    924       .addReg(reg_res).addReg(reg_v2);
    925     break;
    926   }
    927   case Alpha::SWAP32:
    928   case Alpha::SWAP64: {
    929     BuildMI(llscMBB, dl, TII->get(Alpha::BISr), reg_store)
    930       .addReg(reg_v2).addReg(reg_v2);
    931     break;
    932   }
    933   }
    934   BuildMI(llscMBB, dl, TII->get(is32 ? Alpha::STL_C : Alpha::STQ_C), reg_store)
    935     .addReg(reg_store).addImm(0).addReg(reg_ptr);
    936   BuildMI(llscMBB, dl, TII->get(Alpha::BEQ))
    937     .addImm(0).addReg(reg_store).addMBB(llscMBB);
    938   BuildMI(llscMBB, dl, TII->get(Alpha::BR)).addMBB(sinkMBB);
    939 
    940   thisMBB->addSuccessor(llscMBB);
    941   llscMBB->addSuccessor(llscMBB);
    942   llscMBB->addSuccessor(sinkMBB);
    943   MI->eraseFromParent();   // The pseudo instruction is gone now.
    944 
    945   return sinkMBB;
    946 }
    947 
    948 bool
    949 AlphaTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
    950   // The Alpha target isn't yet aware of offsets.
    951   return false;
    952 }
    953 
    954 bool AlphaTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT) const {
    955   if (VT != MVT::f32 && VT != MVT::f64)
    956     return false;
    957   // +0.0   F31
    958   // +0.0f  F31
    959   // -0.0  -F31
    960   // -0.0f -F31
    961   return Imm.isZero() || Imm.isNegZero();
    962 }
    963