MSP430ISelLowering.cpp revision fc5d305597ea6336d75bd7f3b741e8d57d6a5105 
1//===-- MSP430ISelLowering.cpp - MSP430 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 MSP430TargetLowering class.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "msp430-lower"
15
16#include "MSP430ISelLowering.h"
17#include "MSP430.h"
18#include "MSP430MachineFunctionInfo.h"
19#include "MSP430TargetMachine.h"
20#include "MSP430Subtarget.h"
21#include "llvm/DerivedTypes.h"
22#include "llvm/Function.h"
23#include "llvm/Intrinsics.h"
24#include "llvm/CallingConv.h"
25#include "llvm/GlobalVariable.h"
26#include "llvm/GlobalAlias.h"
27#include "llvm/CodeGen/CallingConvLower.h"
28#include "llvm/CodeGen/MachineFrameInfo.h"
29#include "llvm/CodeGen/MachineFunction.h"
30#include "llvm/CodeGen/MachineInstrBuilder.h"
31#include "llvm/CodeGen/MachineRegisterInfo.h"
32#include "llvm/CodeGen/PseudoSourceValue.h"
33#include "llvm/CodeGen/SelectionDAGISel.h"
34#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
35#include "llvm/CodeGen/ValueTypes.h"
36#include "llvm/Support/CommandLine.h"
37#include "llvm/Support/Debug.h"
38#include "llvm/Support/ErrorHandling.h"
39#include "llvm/Support/raw_ostream.h"
40#include "llvm/ADT/VectorExtras.h"
41using namespace llvm;
42
43typedef enum {
44  NoHWMult,
45  HWMultIntr,
46  HWMultNoIntr
47} HWMultUseMode;
48
49static cl::opt<HWMultUseMode>
50HWMultMode("msp430-hwmult-mode",
51           cl::desc("Hardware multiplier use mode"),
52           cl::init(HWMultNoIntr),
53           cl::values(
54             clEnumValN(NoHWMult, "no",
55                "Do not use hardware multiplier"),
56             clEnumValN(HWMultIntr, "interrupts",
57                "Assume hardware multiplier can be used inside interrupts"),
58             clEnumValN(HWMultNoIntr, "use",
59                "Assume hardware multiplier cannot be used inside interrupts"),
60             clEnumValEnd));
61
62MSP430TargetLowering::MSP430TargetLowering(MSP430TargetMachine &tm) :
63  TargetLowering(tm, new TargetLoweringObjectFileELF()),
64  Subtarget(*tm.getSubtargetImpl()), TM(tm) {
65
66  TD = getTargetData();
67
68  // Set up the register classes.
69  addRegisterClass(MVT::i8,  MSP430::GR8RegisterClass);
70  addRegisterClass(MVT::i16, MSP430::GR16RegisterClass);
71
72  // Compute derived properties from the register classes
73  computeRegisterProperties();
74
75  // Provide all sorts of operation actions
76
77  // Division is expensive
78  setIntDivIsCheap(false);
79
80  setStackPointerRegisterToSaveRestore(MSP430::SPW);
81  setBooleanContents(ZeroOrOneBooleanContent);
82  setSchedulingPreference(Sched::Latency);
83
84  // We have post-incremented loads / stores.
85  setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
86  setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);
87
88  setLoadExtAction(ISD::EXTLOAD,  MVT::i1,  Promote);
89  setLoadExtAction(ISD::SEXTLOAD, MVT::i1,  Promote);
90  setLoadExtAction(ISD::ZEXTLOAD, MVT::i1,  Promote);
91  setLoadExtAction(ISD::SEXTLOAD, MVT::i8,  Expand);
92  setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand);
93
94  // We don't have any truncstores
95  setTruncStoreAction(MVT::i16, MVT::i8, Expand);
96
97  setOperationAction(ISD::SRA,              MVT::i8,    Custom);
98  setOperationAction(ISD::SHL,              MVT::i8,    Custom);
99  setOperationAction(ISD::SRL,              MVT::i8,    Custom);
100  setOperationAction(ISD::SRA,              MVT::i16,   Custom);
101  setOperationAction(ISD::SHL,              MVT::i16,   Custom);
102  setOperationAction(ISD::SRL,              MVT::i16,   Custom);
103  setOperationAction(ISD::ROTL,             MVT::i8,    Expand);
104  setOperationAction(ISD::ROTR,             MVT::i8,    Expand);
105  setOperationAction(ISD::ROTL,             MVT::i16,   Expand);
106  setOperationAction(ISD::ROTR,             MVT::i16,   Expand);
107  setOperationAction(ISD::GlobalAddress,    MVT::i16,   Custom);
108  setOperationAction(ISD::ExternalSymbol,   MVT::i16,   Custom);
109  setOperationAction(ISD::BlockAddress,     MVT::i16,   Custom);
110  setOperationAction(ISD::BR_JT,            MVT::Other, Expand);
111  setOperationAction(ISD::BR_CC,            MVT::i8,    Custom);
112  setOperationAction(ISD::BR_CC,            MVT::i16,   Custom);
113  setOperationAction(ISD::BRCOND,           MVT::Other, Expand);
114  setOperationAction(ISD::SETCC,            MVT::i8,    Custom);
115  setOperationAction(ISD::SETCC,            MVT::i16,   Custom);
116  setOperationAction(ISD::SELECT,           MVT::i8,    Expand);
117  setOperationAction(ISD::SELECT,           MVT::i16,   Expand);
118  setOperationAction(ISD::SELECT_CC,        MVT::i8,    Custom);
119  setOperationAction(ISD::SELECT_CC,        MVT::i16,   Custom);
120  setOperationAction(ISD::SIGN_EXTEND,      MVT::i16,   Custom);
121  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i8, Expand);
122  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i16, Expand);
123
124  setOperationAction(ISD::CTTZ,             MVT::i8,    Expand);
125  setOperationAction(ISD::CTTZ,             MVT::i16,   Expand);
126  setOperationAction(ISD::CTLZ,             MVT::i8,    Expand);
127  setOperationAction(ISD::CTLZ,             MVT::i16,   Expand);
128  setOperationAction(ISD::CTPOP,            MVT::i8,    Expand);
129  setOperationAction(ISD::CTPOP,            MVT::i16,   Expand);
130
131  setOperationAction(ISD::SHL_PARTS,        MVT::i8,    Expand);
132  setOperationAction(ISD::SHL_PARTS,        MVT::i16,   Expand);
133  setOperationAction(ISD::SRL_PARTS,        MVT::i8,    Expand);
134  setOperationAction(ISD::SRL_PARTS,        MVT::i16,   Expand);
135  setOperationAction(ISD::SRA_PARTS,        MVT::i8,    Expand);
136  setOperationAction(ISD::SRA_PARTS,        MVT::i16,   Expand);
137
138  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1,   Expand);
139
140  // FIXME: Implement efficiently multiplication by a constant
141  setOperationAction(ISD::MUL,              MVT::i8,    Expand);
142  setOperationAction(ISD::MULHS,            MVT::i8,    Expand);
143  setOperationAction(ISD::MULHU,            MVT::i8,    Expand);
144  setOperationAction(ISD::SMUL_LOHI,        MVT::i8,    Expand);
145  setOperationAction(ISD::UMUL_LOHI,        MVT::i8,    Expand);
146  setOperationAction(ISD::MUL,              MVT::i16,   Expand);
147  setOperationAction(ISD::MULHS,            MVT::i16,   Expand);
148  setOperationAction(ISD::MULHU,            MVT::i16,   Expand);
149  setOperationAction(ISD::SMUL_LOHI,        MVT::i16,   Expand);
150  setOperationAction(ISD::UMUL_LOHI,        MVT::i16,   Expand);
151
152  setOperationAction(ISD::UDIV,             MVT::i8,    Expand);
153  setOperationAction(ISD::UDIVREM,          MVT::i8,    Expand);
154  setOperationAction(ISD::UREM,             MVT::i8,    Expand);
155  setOperationAction(ISD::SDIV,             MVT::i8,    Expand);
156  setOperationAction(ISD::SDIVREM,          MVT::i8,    Expand);
157  setOperationAction(ISD::SREM,             MVT::i8,    Expand);
158  setOperationAction(ISD::UDIV,             MVT::i16,   Expand);
159  setOperationAction(ISD::UDIVREM,          MVT::i16,   Expand);
160  setOperationAction(ISD::UREM,             MVT::i16,   Expand);
161  setOperationAction(ISD::SDIV,             MVT::i16,   Expand);
162  setOperationAction(ISD::SDIVREM,          MVT::i16,   Expand);
163  setOperationAction(ISD::SREM,             MVT::i16,   Expand);
164
165  // Libcalls names.
166  if (HWMultMode == HWMultIntr) {
167    setLibcallName(RTLIB::MUL_I8,  "__mulqi3hw");
168    setLibcallName(RTLIB::MUL_I16, "__mulhi3hw");
169  } else if (HWMultMode == HWMultNoIntr) {
170    setLibcallName(RTLIB::MUL_I8,  "__mulqi3hw_noint");
171    setLibcallName(RTLIB::MUL_I16, "__mulhi3hw_noint");
172  }
173
174  setMinFunctionAlignment(1);
175  setPrefFunctionAlignment(2);
176}
177
178SDValue MSP430TargetLowering::LowerOperation(SDValue Op,
179                                             SelectionDAG &DAG) const {
180  switch (Op.getOpcode()) {
181  case ISD::SHL: // FALLTHROUGH
182  case ISD::SRL:
183  case ISD::SRA:              return LowerShifts(Op, DAG);
184  case ISD::GlobalAddress:    return LowerGlobalAddress(Op, DAG);
185  case ISD::BlockAddress:     return LowerBlockAddress(Op, DAG);
186  case ISD::ExternalSymbol:   return LowerExternalSymbol(Op, DAG);
187  case ISD::SETCC:            return LowerSETCC(Op, DAG);
188  case ISD::BR_CC:            return LowerBR_CC(Op, DAG);
189  case ISD::SELECT_CC:        return LowerSELECT_CC(Op, DAG);
190  case ISD::SIGN_EXTEND:      return LowerSIGN_EXTEND(Op, DAG);
191  case ISD::RETURNADDR:       return LowerRETURNADDR(Op, DAG);
192  case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
193  default:
194    llvm_unreachable("unimplemented operand");
195    return SDValue();
196  }
197}
198
199//===----------------------------------------------------------------------===//
200//                       MSP430 Inline Assembly Support
201//===----------------------------------------------------------------------===//
202
203/// getConstraintType - Given a constraint letter, return the type of
204/// constraint it is for this target.
205TargetLowering::ConstraintType
206MSP430TargetLowering::getConstraintType(const std::string &Constraint) const {
207  if (Constraint.size() == 1) {
208    switch (Constraint[0]) {
209    case 'r':
210      return C_RegisterClass;
211    default:
212      break;
213    }
214  }
215  return TargetLowering::getConstraintType(Constraint);
216}
217
218std::pair<unsigned, const TargetRegisterClass*>
219MSP430TargetLowering::
220getRegForInlineAsmConstraint(const std::string &Constraint,
221                             EVT VT) const {
222  if (Constraint.size() == 1) {
223    // GCC Constraint Letters
224    switch (Constraint[0]) {
225    default: break;
226    case 'r':   // GENERAL_REGS
227      if (VT == MVT::i8)
228        return std::make_pair(0U, MSP430::GR8RegisterClass);
229
230      return std::make_pair(0U, MSP430::GR16RegisterClass);
231    }
232  }
233
234  return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
235}
236
237//===----------------------------------------------------------------------===//
238//                      Calling Convention Implementation
239//===----------------------------------------------------------------------===//
240
241#include "MSP430GenCallingConv.inc"
242
243SDValue
244MSP430TargetLowering::LowerFormalArguments(SDValue Chain,
245                                           CallingConv::ID CallConv,
246                                           bool isVarArg,
247                                           const SmallVectorImpl<ISD::InputArg>
248                                             &Ins,
249                                           DebugLoc dl,
250                                           SelectionDAG &DAG,
251                                           SmallVectorImpl<SDValue> &InVals)
252                                             const {
253
254  switch (CallConv) {
255  default:
256    llvm_unreachable("Unsupported calling convention");
257  case CallingConv::C:
258  case CallingConv::Fast:
259    return LowerCCCArguments(Chain, CallConv, isVarArg, Ins, dl, DAG, InVals);
260  case CallingConv::MSP430_INTR:
261   if (Ins.empty())
262     return Chain;
263   else {
264    report_fatal_error("ISRs cannot have arguments");
265    return SDValue();
266   }
267  }
268}
269
270SDValue
271MSP430TargetLowering::LowerCall(SDValue Chain, SDValue Callee,
272                                CallingConv::ID CallConv, bool isVarArg,
273                                bool &isTailCall,
274                                const SmallVectorImpl<ISD::OutputArg> &Outs,
275                                const SmallVectorImpl<SDValue> &OutVals,
276                                const SmallVectorImpl<ISD::InputArg> &Ins,
277                                DebugLoc dl, SelectionDAG &DAG,
278                                SmallVectorImpl<SDValue> &InVals) const {
279  // MSP430 target does not yet support tail call optimization.
280  isTailCall = false;
281
282  switch (CallConv) {
283  default:
284    llvm_unreachable("Unsupported calling convention");
285  case CallingConv::Fast:
286  case CallingConv::C:
287    return LowerCCCCallTo(Chain, Callee, CallConv, isVarArg, isTailCall,
288                          Outs, OutVals, Ins, dl, DAG, InVals);
289  case CallingConv::MSP430_INTR:
290    report_fatal_error("ISRs cannot be called directly");
291    return SDValue();
292  }
293}
294
295/// LowerCCCArguments - transform physical registers into virtual registers and
296/// generate load operations for arguments places on the stack.
297// FIXME: struct return stuff
298// FIXME: varargs
299SDValue
300MSP430TargetLowering::LowerCCCArguments(SDValue Chain,
301                                        CallingConv::ID CallConv,
302                                        bool isVarArg,
303                                        const SmallVectorImpl<ISD::InputArg>
304                                          &Ins,
305                                        DebugLoc dl,
306                                        SelectionDAG &DAG,
307                                        SmallVectorImpl<SDValue> &InVals)
308                                          const {
309  MachineFunction &MF = DAG.getMachineFunction();
310  MachineFrameInfo *MFI = MF.getFrameInfo();
311  MachineRegisterInfo &RegInfo = MF.getRegInfo();
312
313  // Assign locations to all of the incoming arguments.
314  SmallVector<CCValAssign, 16> ArgLocs;
315  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
316                 ArgLocs, *DAG.getContext());
317  CCInfo.AnalyzeFormalArguments(Ins, CC_MSP430);
318
319  assert(!isVarArg && "Varargs not supported yet");
320
321  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
322    CCValAssign &VA = ArgLocs[i];
323    if (VA.isRegLoc()) {
324      // Arguments passed in registers
325      EVT RegVT = VA.getLocVT();
326      switch (RegVT.getSimpleVT().SimpleTy) {
327      default:
328        {
329#ifndef NDEBUG
330          errs() << "LowerFormalArguments Unhandled argument type: "
331               << RegVT.getSimpleVT().SimpleTy << "\n";
332#endif
333          llvm_unreachable(0);
334        }
335      case MVT::i16:
336        unsigned VReg =
337          RegInfo.createVirtualRegister(MSP430::GR16RegisterClass);
338        RegInfo.addLiveIn(VA.getLocReg(), VReg);
339        SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, VReg, RegVT);
340
341        // If this is an 8-bit value, it is really passed promoted to 16
342        // bits. Insert an assert[sz]ext to capture this, then truncate to the
343        // right size.
344        if (VA.getLocInfo() == CCValAssign::SExt)
345          ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
346                                 DAG.getValueType(VA.getValVT()));
347        else if (VA.getLocInfo() == CCValAssign::ZExt)
348          ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
349                                 DAG.getValueType(VA.getValVT()));
350
351        if (VA.getLocInfo() != CCValAssign::Full)
352          ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
353
354        InVals.push_back(ArgValue);
355      }
356    } else {
357      // Sanity check
358      assert(VA.isMemLoc());
359      // Load the argument to a virtual register
360      unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
361      if (ObjSize > 2) {
362        errs() << "LowerFormalArguments Unhandled argument type: "
363             << EVT(VA.getLocVT()).getEVTString()
364             << "\n";
365      }
366      // Create the frame index object for this incoming parameter...
367      int FI = MFI->CreateFixedObject(ObjSize, VA.getLocMemOffset(), true);
368
369      // Create the SelectionDAG nodes corresponding to a load
370      //from this parameter
371      SDValue FIN = DAG.getFrameIndex(FI, MVT::i16);
372      InVals.push_back(DAG.getLoad(VA.getLocVT(), dl, Chain, FIN,
373                                   MachinePointerInfo::getFixedStack(FI),
374                                   false, false, 0));
375    }
376  }
377
378  return Chain;
379}
380
381SDValue
382MSP430TargetLowering::LowerReturn(SDValue Chain,
383                                  CallingConv::ID CallConv, bool isVarArg,
384                                  const SmallVectorImpl<ISD::OutputArg> &Outs,
385                                  const SmallVectorImpl<SDValue> &OutVals,
386                                  DebugLoc dl, SelectionDAG &DAG) const {
387
388  // CCValAssign - represent the assignment of the return value to a location
389  SmallVector<CCValAssign, 16> RVLocs;
390
391  // ISRs cannot return any value.
392  if (CallConv == CallingConv::MSP430_INTR && !Outs.empty()) {
393    report_fatal_error("ISRs cannot return any value");
394    return SDValue();
395  }
396
397  // CCState - Info about the registers and stack slot.
398  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
399                 RVLocs, *DAG.getContext());
400
401  // Analize return values.
402  CCInfo.AnalyzeReturn(Outs, RetCC_MSP430);
403
404  // If this is the first return lowered for this function, add the regs to the
405  // liveout set for the function.
406  if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
407    for (unsigned i = 0; i != RVLocs.size(); ++i)
408      if (RVLocs[i].isRegLoc())
409        DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
410  }
411
412  SDValue Flag;
413
414  // Copy the result values into the output registers.
415  for (unsigned i = 0; i != RVLocs.size(); ++i) {
416    CCValAssign &VA = RVLocs[i];
417    assert(VA.isRegLoc() && "Can only return in registers!");
418
419    Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
420                             OutVals[i], Flag);
421
422    // Guarantee that all emitted copies are stuck together,
423    // avoiding something bad.
424    Flag = Chain.getValue(1);
425  }
426
427  unsigned Opc = (CallConv == CallingConv::MSP430_INTR ?
428                  MSP430ISD::RETI_FLAG : MSP430ISD::RET_FLAG);
429
430  if (Flag.getNode())
431    return DAG.getNode(Opc, dl, MVT::Other, Chain, Flag);
432
433  // Return Void
434  return DAG.getNode(Opc, dl, MVT::Other, Chain);
435}
436
437/// LowerCCCCallTo - functions arguments are copied from virtual regs to
438/// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
439/// TODO: sret.
440SDValue
441MSP430TargetLowering::LowerCCCCallTo(SDValue Chain, SDValue Callee,
442                                     CallingConv::ID CallConv, bool isVarArg,
443                                     bool isTailCall,
444                                     const SmallVectorImpl<ISD::OutputArg>
445                                       &Outs,
446                                     const SmallVectorImpl<SDValue> &OutVals,
447                                     const SmallVectorImpl<ISD::InputArg> &Ins,
448                                     DebugLoc dl, SelectionDAG &DAG,
449                                     SmallVectorImpl<SDValue> &InVals) const {
450  // Analyze operands of the call, assigning locations to each operand.
451  SmallVector<CCValAssign, 16> ArgLocs;
452  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
453                 ArgLocs, *DAG.getContext());
454
455  CCInfo.AnalyzeCallOperands(Outs, CC_MSP430);
456
457  // Get a count of how many bytes are to be pushed on the stack.
458  unsigned NumBytes = CCInfo.getNextStackOffset();
459
460  Chain = DAG.getCALLSEQ_START(Chain ,DAG.getConstant(NumBytes,
461                                                      getPointerTy(), true));
462
463  SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
464  SmallVector<SDValue, 12> MemOpChains;
465  SDValue StackPtr;
466
467  // Walk the register/memloc assignments, inserting copies/loads.
468  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
469    CCValAssign &VA = ArgLocs[i];
470
471    SDValue Arg = OutVals[i];
472
473    // Promote the value if needed.
474    switch (VA.getLocInfo()) {
475      default: llvm_unreachable("Unknown loc info!");
476      case CCValAssign::Full: break;
477      case CCValAssign::SExt:
478        Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
479        break;
480      case CCValAssign::ZExt:
481        Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
482        break;
483      case CCValAssign::AExt:
484        Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
485        break;
486    }
487
488    // Arguments that can be passed on register must be kept at RegsToPass
489    // vector
490    if (VA.isRegLoc()) {
491      RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
492    } else {
493      assert(VA.isMemLoc());
494
495      if (StackPtr.getNode() == 0)
496        StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SPW, getPointerTy());
497
498      SDValue PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(),
499                                   StackPtr,
500                                   DAG.getIntPtrConstant(VA.getLocMemOffset()));
501
502
503      MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
504                                         MachinePointerInfo(),false, false, 0));
505    }
506  }
507
508  // Transform all store nodes into one single node because all store nodes are
509  // independent of each other.
510  if (!MemOpChains.empty())
511    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
512                        &MemOpChains[0], MemOpChains.size());
513
514  // Build a sequence of copy-to-reg nodes chained together with token chain and
515  // flag operands which copy the outgoing args into registers.  The InFlag in
516  // necessary since all emitted instructions must be stuck together.
517  SDValue InFlag;
518  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
519    Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
520                             RegsToPass[i].second, InFlag);
521    InFlag = Chain.getValue(1);
522  }
523
524  // If the callee is a GlobalAddress node (quite common, every direct call is)
525  // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
526  // Likewise ExternalSymbol -> TargetExternalSymbol.
527  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
528    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl, MVT::i16);
529  else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
530    Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16);
531
532  // Returns a chain & a flag for retval copy to use.
533  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
534  SmallVector<SDValue, 8> Ops;
535  Ops.push_back(Chain);
536  Ops.push_back(Callee);
537
538  // Add argument registers to the end of the list so that they are
539  // known live into the call.
540  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
541    Ops.push_back(DAG.getRegister(RegsToPass[i].first,
542                                  RegsToPass[i].second.getValueType()));
543
544  if (InFlag.getNode())
545    Ops.push_back(InFlag);
546
547  Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, &Ops[0], Ops.size());
548  InFlag = Chain.getValue(1);
549
550  // Create the CALLSEQ_END node.
551  Chain = DAG.getCALLSEQ_END(Chain,
552                             DAG.getConstant(NumBytes, getPointerTy(), true),
553                             DAG.getConstant(0, getPointerTy(), true),
554                             InFlag);
555  InFlag = Chain.getValue(1);
556
557  // Handle result values, copying them out of physregs into vregs that we
558  // return.
559  return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, dl,
560                         DAG, InVals);
561}
562
563/// LowerCallResult - Lower the result values of a call into the
564/// appropriate copies out of appropriate physical registers.
565///
566SDValue
567MSP430TargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
568                                      CallingConv::ID CallConv, bool isVarArg,
569                                      const SmallVectorImpl<ISD::InputArg> &Ins,
570                                      DebugLoc dl, SelectionDAG &DAG,
571                                      SmallVectorImpl<SDValue> &InVals) const {
572
573  // Assign locations to each value returned by this call.
574  SmallVector<CCValAssign, 16> RVLocs;
575  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
576                 RVLocs, *DAG.getContext());
577
578  CCInfo.AnalyzeCallResult(Ins, RetCC_MSP430);
579
580  // Copy all of the result registers out of their specified physreg.
581  for (unsigned i = 0; i != RVLocs.size(); ++i) {
582    Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
583                               RVLocs[i].getValVT(), InFlag).getValue(1);
584    InFlag = Chain.getValue(2);
585    InVals.push_back(Chain.getValue(0));
586  }
587
588  return Chain;
589}
590
591SDValue MSP430TargetLowering::LowerShifts(SDValue Op,
592                                          SelectionDAG &DAG) const {
593  unsigned Opc = Op.getOpcode();
594  SDNode* N = Op.getNode();
595  EVT VT = Op.getValueType();
596  DebugLoc dl = N->getDebugLoc();
597
598  // Expand non-constant shifts to loops:
599  if (!isa<ConstantSDNode>(N->getOperand(1)))
600    switch (Opc) {
601    default:
602      assert(0 && "Invalid shift opcode!");
603    case ISD::SHL:
604      return DAG.getNode(MSP430ISD::SHL, dl,
605                         VT, N->getOperand(0), N->getOperand(1));
606    case ISD::SRA:
607      return DAG.getNode(MSP430ISD::SRA, dl,
608                         VT, N->getOperand(0), N->getOperand(1));
609    case ISD::SRL:
610      return DAG.getNode(MSP430ISD::SRL, dl,
611                         VT, N->getOperand(0), N->getOperand(1));
612    }
613
614  uint64_t ShiftAmount = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
615
616  // Expand the stuff into sequence of shifts.
617  // FIXME: for some shift amounts this might be done better!
618  // E.g.: foo >> (8 + N) => sxt(swpb(foo)) >> N
619  SDValue Victim = N->getOperand(0);
620
621  if (Opc == ISD::SRL && ShiftAmount) {
622    // Emit a special goodness here:
623    // srl A, 1 => clrc; rrc A
624    Victim = DAG.getNode(MSP430ISD::RRC, dl, VT, Victim);
625    ShiftAmount -= 1;
626  }
627
628  while (ShiftAmount--)
629    Victim = DAG.getNode((Opc == ISD::SHL ? MSP430ISD::RLA : MSP430ISD::RRA),
630                         dl, VT, Victim);
631
632  return Victim;
633}
634
635SDValue MSP430TargetLowering::LowerGlobalAddress(SDValue Op,
636                                                 SelectionDAG &DAG) const {
637  const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
638  int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
639
640  // Create the TargetGlobalAddress node, folding in the constant offset.
641  SDValue Result = DAG.getTargetGlobalAddress(GV, Op.getDebugLoc(),
642                                              getPointerTy(), Offset);
643  return DAG.getNode(MSP430ISD::Wrapper, Op.getDebugLoc(),
644                     getPointerTy(), Result);
645}
646
647SDValue MSP430TargetLowering::LowerExternalSymbol(SDValue Op,
648                                                  SelectionDAG &DAG) const {
649  DebugLoc dl = Op.getDebugLoc();
650  const char *Sym = cast<ExternalSymbolSDNode>(Op)->getSymbol();
651  SDValue Result = DAG.getTargetExternalSymbol(Sym, getPointerTy());
652
653  return DAG.getNode(MSP430ISD::Wrapper, dl, getPointerTy(), Result);;
654}
655
656SDValue MSP430TargetLowering::LowerBlockAddress(SDValue Op,
657                                                SelectionDAG &DAG) const {
658  DebugLoc dl = Op.getDebugLoc();
659  const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
660  SDValue Result = DAG.getBlockAddress(BA, getPointerTy(), /*isTarget=*/true);
661
662  return DAG.getNode(MSP430ISD::Wrapper, dl, getPointerTy(), Result);;
663}
664
665static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, SDValue &TargetCC,
666                       ISD::CondCode CC,
667                       DebugLoc dl, SelectionDAG &DAG) {
668  // FIXME: Handle bittests someday
669  assert(!LHS.getValueType().isFloatingPoint() && "We don't handle FP yet");
670
671  // FIXME: Handle jump negative someday
672  MSP430CC::CondCodes TCC = MSP430CC::COND_INVALID;
673  switch (CC) {
674  default: llvm_unreachable("Invalid integer condition!");
675  case ISD::SETEQ:
676    TCC = MSP430CC::COND_E;     // aka COND_Z
677    // Minor optimization: if LHS is a constant, swap operands, then the
678    // constant can be folded into comparison.
679    if (LHS.getOpcode() == ISD::Constant)
680      std::swap(LHS, RHS);
681    break;
682  case ISD::SETNE:
683    TCC = MSP430CC::COND_NE;    // aka COND_NZ
684    // Minor optimization: if LHS is a constant, swap operands, then the
685    // constant can be folded into comparison.
686    if (LHS.getOpcode() == ISD::Constant)
687      std::swap(LHS, RHS);
688    break;
689  case ISD::SETULE:
690    std::swap(LHS, RHS);        // FALLTHROUGH
691  case ISD::SETUGE:
692    // Turn lhs u>= rhs with lhs constant into rhs u< lhs+1, this allows us to
693    // fold constant into instruction.
694    if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
695      LHS = RHS;
696      RHS = DAG.getConstant(C->getSExtValue() + 1, C->getValueType(0));
697      TCC = MSP430CC::COND_LO;
698      break;
699    }
700    TCC = MSP430CC::COND_HS;    // aka COND_C
701    break;
702  case ISD::SETUGT:
703    std::swap(LHS, RHS);        // FALLTHROUGH
704  case ISD::SETULT:
705    // Turn lhs u< rhs with lhs constant into rhs u>= lhs+1, this allows us to
706    // fold constant into instruction.
707    if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
708      LHS = RHS;
709      RHS = DAG.getConstant(C->getSExtValue() + 1, C->getValueType(0));
710      TCC = MSP430CC::COND_HS;
711      break;
712    }
713    TCC = MSP430CC::COND_LO;    // aka COND_NC
714    break;
715  case ISD::SETLE:
716    std::swap(LHS, RHS);        // FALLTHROUGH
717  case ISD::SETGE:
718    // Turn lhs >= rhs with lhs constant into rhs < lhs+1, this allows us to
719    // fold constant into instruction.
720    if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
721      LHS = RHS;
722      RHS = DAG.getConstant(C->getSExtValue() + 1, C->getValueType(0));
723      TCC = MSP430CC::COND_L;
724      break;
725    }
726    TCC = MSP430CC::COND_GE;
727    break;
728  case ISD::SETGT:
729    std::swap(LHS, RHS);        // FALLTHROUGH
730  case ISD::SETLT:
731    // Turn lhs < rhs with lhs constant into rhs >= lhs+1, this allows us to
732    // fold constant into instruction.
733    if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
734      LHS = RHS;
735      RHS = DAG.getConstant(C->getSExtValue() + 1, C->getValueType(0));
736      TCC = MSP430CC::COND_GE;
737      break;
738    }
739    TCC = MSP430CC::COND_L;
740    break;
741  }
742
743  TargetCC = DAG.getConstant(TCC, MVT::i8);
744  return DAG.getNode(MSP430ISD::CMP, dl, MVT::Glue, LHS, RHS);
745}
746
747
748SDValue MSP430TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
749  SDValue Chain = Op.getOperand(0);
750  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
751  SDValue LHS   = Op.getOperand(2);
752  SDValue RHS   = Op.getOperand(3);
753  SDValue Dest  = Op.getOperand(4);
754  DebugLoc dl   = Op.getDebugLoc();
755
756  SDValue TargetCC;
757  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
758
759  return DAG.getNode(MSP430ISD::BR_CC, dl, Op.getValueType(),
760                     Chain, Dest, TargetCC, Flag);
761}
762
763SDValue MSP430TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
764  SDValue LHS   = Op.getOperand(0);
765  SDValue RHS   = Op.getOperand(1);
766  DebugLoc dl   = Op.getDebugLoc();
767
768  // If we are doing an AND and testing against zero, then the CMP
769  // will not be generated.  The AND (or BIT) will generate the condition codes,
770  // but they are different from CMP.
771  // FIXME: since we're doing a post-processing, use a pseudoinstr here, so
772  // lowering & isel wouldn't diverge.
773  bool andCC = false;
774  if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS)) {
775    if (RHSC->isNullValue() && LHS.hasOneUse() &&
776        (LHS.getOpcode() == ISD::AND ||
777         (LHS.getOpcode() == ISD::TRUNCATE &&
778          LHS.getOperand(0).getOpcode() == ISD::AND))) {
779      andCC = true;
780    }
781  }
782  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
783  SDValue TargetCC;
784  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
785
786  // Get the condition codes directly from the status register, if its easy.
787  // Otherwise a branch will be generated.  Note that the AND and BIT
788  // instructions generate different flags than CMP, the carry bit can be used
789  // for NE/EQ.
790  bool Invert = false;
791  bool Shift = false;
792  bool Convert = true;
793  switch (cast<ConstantSDNode>(TargetCC)->getZExtValue()) {
794   default:
795    Convert = false;
796    break;
797   case MSP430CC::COND_HS:
798     // Res = SRW & 1, no processing is required
799     break;
800   case MSP430CC::COND_LO:
801     // Res = ~(SRW & 1)
802     Invert = true;
803     break;
804   case MSP430CC::COND_NE:
805     if (andCC) {
806       // C = ~Z, thus Res = SRW & 1, no processing is required
807     } else {
808       // Res = ~((SRW >> 1) & 1)
809       Shift = true;
810       Invert = true;
811     }
812     break;
813   case MSP430CC::COND_E:
814     Shift = true;
815     // C = ~Z for AND instruction, thus we can put Res = ~(SRW & 1), however,
816     // Res = (SRW >> 1) & 1 is 1 word shorter.
817     break;
818  }
819  EVT VT = Op.getValueType();
820  SDValue One  = DAG.getConstant(1, VT);
821  if (Convert) {
822    SDValue SR = DAG.getCopyFromReg(DAG.getEntryNode(), dl, MSP430::SRW,
823                                    MVT::i16, Flag);
824    if (Shift)
825      // FIXME: somewhere this is turned into a SRL, lower it MSP specific?
826      SR = DAG.getNode(ISD::SRA, dl, MVT::i16, SR, One);
827    SR = DAG.getNode(ISD::AND, dl, MVT::i16, SR, One);
828    if (Invert)
829      SR = DAG.getNode(ISD::XOR, dl, MVT::i16, SR, One);
830    return SR;
831  } else {
832    SDValue Zero = DAG.getConstant(0, VT);
833    SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
834    SmallVector<SDValue, 4> Ops;
835    Ops.push_back(One);
836    Ops.push_back(Zero);
837    Ops.push_back(TargetCC);
838    Ops.push_back(Flag);
839    return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, &Ops[0], Ops.size());
840  }
841}
842
843SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op,
844                                             SelectionDAG &DAG) const {
845  SDValue LHS    = Op.getOperand(0);
846  SDValue RHS    = Op.getOperand(1);
847  SDValue TrueV  = Op.getOperand(2);
848  SDValue FalseV = Op.getOperand(3);
849  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
850  DebugLoc dl    = Op.getDebugLoc();
851
852  SDValue TargetCC;
853  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
854
855  SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
856  SmallVector<SDValue, 4> Ops;
857  Ops.push_back(TrueV);
858  Ops.push_back(FalseV);
859  Ops.push_back(TargetCC);
860  Ops.push_back(Flag);
861
862  return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, &Ops[0], Ops.size());
863}
864
865SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op,
866                                               SelectionDAG &DAG) const {
867  SDValue Val = Op.getOperand(0);
868  EVT VT      = Op.getValueType();
869  DebugLoc dl = Op.getDebugLoc();
870
871  assert(VT == MVT::i16 && "Only support i16 for now!");
872
873  return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT,
874                     DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val),
875                     DAG.getValueType(Val.getValueType()));
876}
877
878SDValue
879MSP430TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) const {
880  MachineFunction &MF = DAG.getMachineFunction();
881  MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
882  int ReturnAddrIndex = FuncInfo->getRAIndex();
883
884  if (ReturnAddrIndex == 0) {
885    // Set up a frame object for the return address.
886    uint64_t SlotSize = TD->getPointerSize();
887    ReturnAddrIndex = MF.getFrameInfo()->CreateFixedObject(SlotSize, -SlotSize,
888                                                           true);
889    FuncInfo->setRAIndex(ReturnAddrIndex);
890  }
891
892  return DAG.getFrameIndex(ReturnAddrIndex, getPointerTy());
893}
894
895SDValue MSP430TargetLowering::LowerRETURNADDR(SDValue Op,
896                                              SelectionDAG &DAG) const {
897  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
898  MFI->setReturnAddressIsTaken(true);
899
900  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
901  DebugLoc dl = Op.getDebugLoc();
902
903  if (Depth > 0) {
904    SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
905    SDValue Offset =
906      DAG.getConstant(TD->getPointerSize(), MVT::i16);
907    return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
908                       DAG.getNode(ISD::ADD, dl, getPointerTy(),
909                                   FrameAddr, Offset),
910                       MachinePointerInfo(), false, false, 0);
911  }
912
913  // Just load the return address.
914  SDValue RetAddrFI = getReturnAddressFrameIndex(DAG);
915  return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
916                     RetAddrFI, MachinePointerInfo(), false, false, 0);
917}
918
919SDValue MSP430TargetLowering::LowerFRAMEADDR(SDValue Op,
920                                             SelectionDAG &DAG) const {
921  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
922  MFI->setFrameAddressIsTaken(true);
923
924  EVT VT = Op.getValueType();
925  DebugLoc dl = Op.getDebugLoc();  // FIXME probably not meaningful
926  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
927  SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl,
928                                         MSP430::FPW, VT);
929  while (Depth--)
930    FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr,
931                            MachinePointerInfo(),
932                            false, false, 0);
933  return FrameAddr;
934}
935
936/// getPostIndexedAddressParts - returns true by value, base pointer and
937/// offset pointer and addressing mode by reference if this node can be
938/// combined with a load / store to form a post-indexed load / store.
939bool MSP430TargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
940                                                      SDValue &Base,
941                                                      SDValue &Offset,
942                                                      ISD::MemIndexedMode &AM,
943                                                      SelectionDAG &DAG) const {
944
945  LoadSDNode *LD = cast<LoadSDNode>(N);
946  if (LD->getExtensionType() != ISD::NON_EXTLOAD)
947    return false;
948
949  EVT VT = LD->getMemoryVT();
950  if (VT != MVT::i8 && VT != MVT::i16)
951    return false;
952
953  if (Op->getOpcode() != ISD::ADD)
954    return false;
955
956  if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
957    uint64_t RHSC = RHS->getZExtValue();
958    if ((VT == MVT::i16 && RHSC != 2) ||
959        (VT == MVT::i8 && RHSC != 1))
960      return false;
961
962    Base = Op->getOperand(0);
963    Offset = DAG.getConstant(RHSC, VT);
964    AM = ISD::POST_INC;
965    return true;
966  }
967
968  return false;
969}
970
971
972const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const {
973  switch (Opcode) {
974  default: return NULL;
975  case MSP430ISD::RET_FLAG:           return "MSP430ISD::RET_FLAG";
976  case MSP430ISD::RETI_FLAG:          return "MSP430ISD::RETI_FLAG";
977  case MSP430ISD::RRA:                return "MSP430ISD::RRA";
978  case MSP430ISD::RLA:                return "MSP430ISD::RLA";
979  case MSP430ISD::RRC:                return "MSP430ISD::RRC";
980  case MSP430ISD::CALL:               return "MSP430ISD::CALL";
981  case MSP430ISD::Wrapper:            return "MSP430ISD::Wrapper";
982  case MSP430ISD::BR_CC:              return "MSP430ISD::BR_CC";
983  case MSP430ISD::CMP:                return "MSP430ISD::CMP";
984  case MSP430ISD::SELECT_CC:          return "MSP430ISD::SELECT_CC";
985  case MSP430ISD::SHL:                return "MSP430ISD::SHL";
986  case MSP430ISD::SRA:                return "MSP430ISD::SRA";
987  }
988}
989
990bool MSP430TargetLowering::isTruncateFree(const Type *Ty1,
991                                          const Type *Ty2) const {
992  if (!Ty1->isIntegerTy() || !Ty2->isIntegerTy())
993    return false;
994
995  return (Ty1->getPrimitiveSizeInBits() > Ty2->getPrimitiveSizeInBits());
996}
997
998bool MSP430TargetLowering::isTruncateFree(EVT VT1, EVT VT2) const {
999  if (!VT1.isInteger() || !VT2.isInteger())
1000    return false;
1001
1002  return (VT1.getSizeInBits() > VT2.getSizeInBits());
1003}
1004
1005bool MSP430TargetLowering::isZExtFree(const Type *Ty1, const Type *Ty2) const {
1006  // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1007  return 0 && Ty1->isIntegerTy(8) && Ty2->isIntegerTy(16);
1008}
1009
1010bool MSP430TargetLowering::isZExtFree(EVT VT1, EVT VT2) const {
1011  // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1012  return 0 && VT1 == MVT::i8 && VT2 == MVT::i16;
1013}
1014
1015//===----------------------------------------------------------------------===//
1016//  Other Lowering Code
1017//===----------------------------------------------------------------------===//
1018
1019MachineBasicBlock*
1020MSP430TargetLowering::EmitShiftInstr(MachineInstr *MI,
1021                                     MachineBasicBlock *BB) const {
1022  MachineFunction *F = BB->getParent();
1023  MachineRegisterInfo &RI = F->getRegInfo();
1024  DebugLoc dl = MI->getDebugLoc();
1025  const TargetInstrInfo &TII = *getTargetMachine().getInstrInfo();
1026
1027  unsigned Opc;
1028  const TargetRegisterClass * RC;
1029  switch (MI->getOpcode()) {
1030  default:
1031    assert(0 && "Invalid shift opcode!");
1032  case MSP430::Shl8:
1033   Opc = MSP430::SHL8r1;
1034   RC = MSP430::GR8RegisterClass;
1035   break;
1036  case MSP430::Shl16:
1037   Opc = MSP430::SHL16r1;
1038   RC = MSP430::GR16RegisterClass;
1039   break;
1040  case MSP430::Sra8:
1041   Opc = MSP430::SAR8r1;
1042   RC = MSP430::GR8RegisterClass;
1043   break;
1044  case MSP430::Sra16:
1045   Opc = MSP430::SAR16r1;
1046   RC = MSP430::GR16RegisterClass;
1047   break;
1048  case MSP430::Srl8:
1049   Opc = MSP430::SAR8r1c;
1050   RC = MSP430::GR8RegisterClass;
1051   break;
1052  case MSP430::Srl16:
1053   Opc = MSP430::SAR16r1c;
1054   RC = MSP430::GR16RegisterClass;
1055   break;
1056  }
1057
1058  const BasicBlock *LLVM_BB = BB->getBasicBlock();
1059  MachineFunction::iterator I = BB;
1060  ++I;
1061
1062  // Create loop block
1063  MachineBasicBlock *LoopBB = F->CreateMachineBasicBlock(LLVM_BB);
1064  MachineBasicBlock *RemBB  = F->CreateMachineBasicBlock(LLVM_BB);
1065
1066  F->insert(I, LoopBB);
1067  F->insert(I, RemBB);
1068
1069  // Update machine-CFG edges by transferring all successors of the current
1070  // block to the block containing instructions after shift.
1071  RemBB->splice(RemBB->begin(), BB,
1072                llvm::next(MachineBasicBlock::iterator(MI)),
1073                BB->end());
1074  RemBB->transferSuccessorsAndUpdatePHIs(BB);
1075
1076  // Add adges BB => LoopBB => RemBB, BB => RemBB, LoopBB => LoopBB
1077  BB->addSuccessor(LoopBB);
1078  BB->addSuccessor(RemBB);
1079  LoopBB->addSuccessor(RemBB);
1080  LoopBB->addSuccessor(LoopBB);
1081
1082  unsigned ShiftAmtReg = RI.createVirtualRegister(MSP430::GR8RegisterClass);
1083  unsigned ShiftAmtReg2 = RI.createVirtualRegister(MSP430::GR8RegisterClass);
1084  unsigned ShiftReg = RI.createVirtualRegister(RC);
1085  unsigned ShiftReg2 = RI.createVirtualRegister(RC);
1086  unsigned ShiftAmtSrcReg = MI->getOperand(2).getReg();
1087  unsigned SrcReg = MI->getOperand(1).getReg();
1088  unsigned DstReg = MI->getOperand(0).getReg();
1089
1090  // BB:
1091  // cmp 0, N
1092  // je RemBB
1093  BuildMI(BB, dl, TII.get(MSP430::CMP8ri))
1094    .addReg(ShiftAmtSrcReg).addImm(0);
1095  BuildMI(BB, dl, TII.get(MSP430::JCC))
1096    .addMBB(RemBB)
1097    .addImm(MSP430CC::COND_E);
1098
1099  // LoopBB:
1100  // ShiftReg = phi [%SrcReg, BB], [%ShiftReg2, LoopBB]
1101  // ShiftAmt = phi [%N, BB],      [%ShiftAmt2, LoopBB]
1102  // ShiftReg2 = shift ShiftReg
1103  // ShiftAmt2 = ShiftAmt - 1;
1104  BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftReg)
1105    .addReg(SrcReg).addMBB(BB)
1106    .addReg(ShiftReg2).addMBB(LoopBB);
1107  BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftAmtReg)
1108    .addReg(ShiftAmtSrcReg).addMBB(BB)
1109    .addReg(ShiftAmtReg2).addMBB(LoopBB);
1110  BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1111    .addReg(ShiftReg);
1112  BuildMI(LoopBB, dl, TII.get(MSP430::SUB8ri), ShiftAmtReg2)
1113    .addReg(ShiftAmtReg).addImm(1);
1114  BuildMI(LoopBB, dl, TII.get(MSP430::JCC))
1115    .addMBB(LoopBB)
1116    .addImm(MSP430CC::COND_NE);
1117
1118  // RemBB:
1119  // DestReg = phi [%SrcReg, BB], [%ShiftReg, LoopBB]
1120  BuildMI(*RemBB, RemBB->begin(), dl, TII.get(MSP430::PHI), DstReg)
1121    .addReg(SrcReg).addMBB(BB)
1122    .addReg(ShiftReg2).addMBB(LoopBB);
1123
1124  MI->eraseFromParent();   // The pseudo instruction is gone now.
1125  return RemBB;
1126}
1127
1128MachineBasicBlock*
1129MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
1130                                                  MachineBasicBlock *BB) const {
1131  unsigned Opc = MI->getOpcode();
1132
1133  if (Opc == MSP430::Shl8 || Opc == MSP430::Shl16 ||
1134      Opc == MSP430::Sra8 || Opc == MSP430::Sra16 ||
1135      Opc == MSP430::Srl8 || Opc == MSP430::Srl16)
1136    return EmitShiftInstr(MI, BB);
1137
1138  const TargetInstrInfo &TII = *getTargetMachine().getInstrInfo();
1139  DebugLoc dl = MI->getDebugLoc();
1140
1141  assert((Opc == MSP430::Select16 || Opc == MSP430::Select8) &&
1142         "Unexpected instr type to insert");
1143
1144  // To "insert" a SELECT instruction, we actually have to insert the diamond
1145  // control-flow pattern.  The incoming instruction knows the destination vreg
1146  // to set, the condition code register to branch on, the true/false values to
1147  // select between, and a branch opcode to use.
1148  const BasicBlock *LLVM_BB = BB->getBasicBlock();
1149  MachineFunction::iterator I = BB;
1150  ++I;
1151
1152  //  thisMBB:
1153  //  ...
1154  //   TrueVal = ...
1155  //   cmpTY ccX, r1, r2
1156  //   jCC copy1MBB
1157  //   fallthrough --> copy0MBB
1158  MachineBasicBlock *thisMBB = BB;
1159  MachineFunction *F = BB->getParent();
1160  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
1161  MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB);
1162  F->insert(I, copy0MBB);
1163  F->insert(I, copy1MBB);
1164  // Update machine-CFG edges by transferring all successors of the current
1165  // block to the new block which will contain the Phi node for the select.
1166  copy1MBB->splice(copy1MBB->begin(), BB,
1167                   llvm::next(MachineBasicBlock::iterator(MI)),
1168                   BB->end());
1169  copy1MBB->transferSuccessorsAndUpdatePHIs(BB);
1170  // Next, add the true and fallthrough blocks as its successors.
1171  BB->addSuccessor(copy0MBB);
1172  BB->addSuccessor(copy1MBB);
1173
1174  BuildMI(BB, dl, TII.get(MSP430::JCC))
1175    .addMBB(copy1MBB)
1176    .addImm(MI->getOperand(3).getImm());
1177
1178  //  copy0MBB:
1179  //   %FalseValue = ...
1180  //   # fallthrough to copy1MBB
1181  BB = copy0MBB;
1182
1183  // Update machine-CFG edges
1184  BB->addSuccessor(copy1MBB);
1185
1186  //  copy1MBB:
1187  //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
1188  //  ...
1189  BB = copy1MBB;
1190  BuildMI(*BB, BB->begin(), dl, TII.get(MSP430::PHI),
1191          MI->getOperand(0).getReg())
1192    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB)
1193    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB);
1194
1195  MI->eraseFromParent();   // The pseudo instruction is gone now.
1196  return BB;
1197}
1198