1 //===- PPCInstrInfo.cpp - PowerPC32 Instruction Information -----*- C++ -*-===//
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 contains the PowerPC implementation of the TargetInstrInfo class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "PPCInstrInfo.h"
15 #include "PPC.h"
16 #include "PPCInstrBuilder.h"
17 #include "PPCMachineFunctionInfo.h"
18 #include "PPCTargetMachine.h"
19 #include "PPCHazardRecognizers.h"
20 #include "MCTargetDesc/PPCPredicates.h"
21 #include "llvm/CodeGen/MachineFrameInfo.h"
22 #include "llvm/CodeGen/MachineInstrBuilder.h"
23 #include "llvm/CodeGen/MachineMemOperand.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/CodeGen/PseudoSourceValue.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/TargetRegistry.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include "llvm/ADT/STLExtras.h"
32 
33 #define GET_INSTRINFO_CTOR
34 #include "PPCGenInstrInfo.inc"
35 
36 namespace llvm {
37 extern cl::opt<bool> EnablePPC32RS;  // FIXME (64-bit): See PPCRegisterInfo.cpp.
38 extern cl::opt<bool> EnablePPC64RS;  // FIXME (64-bit): See PPCRegisterInfo.cpp.
39 }
40 
41 using namespace llvm;
42 
43 PPCInstrInfo::PPCInstrInfo(PPCTargetMachine &tm)
44   : PPCGenInstrInfo(PPC::ADJCALLSTACKDOWN, PPC::ADJCALLSTACKUP),
45     TM(tm), RI(*TM.getSubtargetImpl(), *this) {}
46 
47 /// CreateTargetHazardRecognizer - Return the hazard recognizer to use for
48 /// this target when scheduling the DAG.
49 ScheduleHazardRecognizer *PPCInstrInfo::CreateTargetHazardRecognizer(
50   const TargetMachine *TM,
51   const ScheduleDAG *DAG) const {
52   // Should use subtarget info to pick the right hazard recognizer.  For
53   // now, always return a PPC970 recognizer.
54   const TargetInstrInfo *TII = TM->getInstrInfo();
55   assert(TII && "No InstrInfo?");
56 
57   unsigned Directive = TM->getSubtarget<PPCSubtarget>().getDarwinDirective();
58   if (Directive == PPC::DIR_440) {
59     const InstrItineraryData *II = TM->getInstrItineraryData();
60     return new PPCHazardRecognizer440(II, DAG);
61   }
62   else {
63     return new PPCHazardRecognizer970(*TII);
64   }
65 }
66 
67 unsigned PPCInstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
68                                            int &FrameIndex) const {
69   switch (MI->getOpcode()) {
70   default: break;
71   case PPC::LD:
72   case PPC::LWZ:
73   case PPC::LFS:
74   case PPC::LFD:
75     if (MI->getOperand(1).isImm() && !MI->getOperand(1).getImm() &&
76         MI->getOperand(2).isFI()) {
77       FrameIndex = MI->getOperand(2).getIndex();
78       return MI->getOperand(0).getReg();
79     }
80     break;
81   }
82   return 0;
83 }
84 
85 unsigned PPCInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
86                                           int &FrameIndex) const {
87   switch (MI->getOpcode()) {
88   default: break;
89   case PPC::STD:
90   case PPC::STW:
91   case PPC::STFS:
92   case PPC::STFD:
93     if (MI->getOperand(1).isImm() && !MI->getOperand(1).getImm() &&
94         MI->getOperand(2).isFI()) {
95       FrameIndex = MI->getOperand(2).getIndex();
96       return MI->getOperand(0).getReg();
97     }
98     break;
99   }
100   return 0;
101 }
102 
103 // commuteInstruction - We can commute rlwimi instructions, but only if the
104 // rotate amt is zero.  We also have to munge the immediates a bit.
105 MachineInstr *
106 PPCInstrInfo::commuteInstruction(MachineInstr *MI, bool NewMI) const {
107   MachineFunction &MF = *MI->getParent()->getParent();
108 
109   // Normal instructions can be commuted the obvious way.
110   if (MI->getOpcode() != PPC::RLWIMI)
111     return TargetInstrInfoImpl::commuteInstruction(MI, NewMI);
112 
113   // Cannot commute if it has a non-zero rotate count.
114   if (MI->getOperand(3).getImm() != 0)
115     return 0;
116 
117   // If we have a zero rotate count, we have:
118   //   M = mask(MB,ME)
119   //   Op0 = (Op1 & ~M) | (Op2 & M)
120   // Change this to:
121   //   M = mask((ME+1)&31, (MB-1)&31)
122   //   Op0 = (Op2 & ~M) | (Op1 & M)
123 
124   // Swap op1/op2
125   unsigned Reg0 = MI->getOperand(0).getReg();
126   unsigned Reg1 = MI->getOperand(1).getReg();
127   unsigned Reg2 = MI->getOperand(2).getReg();
128   bool Reg1IsKill = MI->getOperand(1).isKill();
129   bool Reg2IsKill = MI->getOperand(2).isKill();
130   bool ChangeReg0 = false;
131   // If machine instrs are no longer in two-address forms, update
132   // destination register as well.
133   if (Reg0 == Reg1) {
134     // Must be two address instruction!
135     assert(MI->getDesc().getOperandConstraint(0, MCOI::TIED_TO) &&
136            "Expecting a two-address instruction!");
137     Reg2IsKill = false;
138     ChangeReg0 = true;
139   }
140 
141   // Masks.
142   unsigned MB = MI->getOperand(4).getImm();
143   unsigned ME = MI->getOperand(5).getImm();
144 
145   if (NewMI) {
146     // Create a new instruction.
147     unsigned Reg0 = ChangeReg0 ? Reg2 : MI->getOperand(0).getReg();
148     bool Reg0IsDead = MI->getOperand(0).isDead();
149     return BuildMI(MF, MI->getDebugLoc(), MI->getDesc())
150       .addReg(Reg0, RegState::Define | getDeadRegState(Reg0IsDead))
151       .addReg(Reg2, getKillRegState(Reg2IsKill))
152       .addReg(Reg1, getKillRegState(Reg1IsKill))
153       .addImm((ME+1) & 31)
154       .addImm((MB-1) & 31);
155   }
156 
157   if (ChangeReg0)
158     MI->getOperand(0).setReg(Reg2);
159   MI->getOperand(2).setReg(Reg1);
160   MI->getOperand(1).setReg(Reg2);
161   MI->getOperand(2).setIsKill(Reg1IsKill);
162   MI->getOperand(1).setIsKill(Reg2IsKill);
163 
164   // Swap the mask around.
165   MI->getOperand(4).setImm((ME+1) & 31);
166   MI->getOperand(5).setImm((MB-1) & 31);
167   return MI;
168 }
169 
170 void PPCInstrInfo::insertNoop(MachineBasicBlock &MBB,
171                               MachineBasicBlock::iterator MI) const {
172   DebugLoc DL;
173   BuildMI(MBB, MI, DL, get(PPC::NOP));
174 }
175 
176 
177 // Branch analysis.
178 bool PPCInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
179                                  MachineBasicBlock *&FBB,
180                                  SmallVectorImpl<MachineOperand> &Cond,
181                                  bool AllowModify) const {
182   // If the block has no terminators, it just falls into the block after it.
183   MachineBasicBlock::iterator I = MBB.end();
184   if (I == MBB.begin())
185     return false;
186   --I;
187   while (I->isDebugValue()) {
188     if (I == MBB.begin())
189       return false;
190     --I;
191   }
192   if (!isUnpredicatedTerminator(I))
193     return false;
194 
195   // Get the last instruction in the block.
196   MachineInstr *LastInst = I;
197 
198   // If there is only one terminator instruction, process it.
199   if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
200     if (LastInst->getOpcode() == PPC::B) {
201       if (!LastInst->getOperand(0).isMBB())
202         return true;
203       TBB = LastInst->getOperand(0).getMBB();
204       return false;
205     } else if (LastInst->getOpcode() == PPC::BCC) {
206       if (!LastInst->getOperand(2).isMBB())
207         return true;
208       // Block ends with fall-through condbranch.
209       TBB = LastInst->getOperand(2).getMBB();
210       Cond.push_back(LastInst->getOperand(0));
211       Cond.push_back(LastInst->getOperand(1));
212       return false;
213     }
214     // Otherwise, don't know what this is.
215     return true;
216   }
217 
218   // Get the instruction before it if it's a terminator.
219   MachineInstr *SecondLastInst = I;
220 
221   // If there are three terminators, we don't know what sort of block this is.
222   if (SecondLastInst && I != MBB.begin() &&
223       isUnpredicatedTerminator(--I))
224     return true;
225 
226   // If the block ends with PPC::B and PPC:BCC, handle it.
227   if (SecondLastInst->getOpcode() == PPC::BCC &&
228       LastInst->getOpcode() == PPC::B) {
229     if (!SecondLastInst->getOperand(2).isMBB() ||
230         !LastInst->getOperand(0).isMBB())
231       return true;
232     TBB =  SecondLastInst->getOperand(2).getMBB();
233     Cond.push_back(SecondLastInst->getOperand(0));
234     Cond.push_back(SecondLastInst->getOperand(1));
235     FBB = LastInst->getOperand(0).getMBB();
236     return false;
237   }
238 
239   // If the block ends with two PPC:Bs, handle it.  The second one is not
240   // executed, so remove it.
241   if (SecondLastInst->getOpcode() == PPC::B &&
242       LastInst->getOpcode() == PPC::B) {
243     if (!SecondLastInst->getOperand(0).isMBB())
244       return true;
245     TBB = SecondLastInst->getOperand(0).getMBB();
246     I = LastInst;
247     if (AllowModify)
248       I->eraseFromParent();
249     return false;
250   }
251 
252   // Otherwise, can't handle this.
253   return true;
254 }
255 
256 unsigned PPCInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
257   MachineBasicBlock::iterator I = MBB.end();
258   if (I == MBB.begin()) return 0;
259   --I;
260   while (I->isDebugValue()) {
261     if (I == MBB.begin())
262       return 0;
263     --I;
264   }
265   if (I->getOpcode() != PPC::B && I->getOpcode() != PPC::BCC)
266     return 0;
267 
268   // Remove the branch.
269   I->eraseFromParent();
270 
271   I = MBB.end();
272 
273   if (I == MBB.begin()) return 1;
274   --I;
275   if (I->getOpcode() != PPC::BCC)
276     return 1;
277 
278   // Remove the branch.
279   I->eraseFromParent();
280   return 2;
281 }
282 
283 unsigned
284 PPCInstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
285                            MachineBasicBlock *FBB,
286                            const SmallVectorImpl<MachineOperand> &Cond,
287                            DebugLoc DL) const {
288   // Shouldn't be a fall through.
289   assert(TBB && "InsertBranch must not be told to insert a fallthrough");
290   assert((Cond.size() == 2 || Cond.size() == 0) &&
291          "PPC branch conditions have two components!");
292 
293   // One-way branch.
294   if (FBB == 0) {
295     if (Cond.empty())   // Unconditional branch
296       BuildMI(&MBB, DL, get(PPC::B)).addMBB(TBB);
297     else                // Conditional branch
298       BuildMI(&MBB, DL, get(PPC::BCC))
299         .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
300     return 1;
301   }
302 
303   // Two-way Conditional Branch.
304   BuildMI(&MBB, DL, get(PPC::BCC))
305     .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
306   BuildMI(&MBB, DL, get(PPC::B)).addMBB(FBB);
307   return 2;
308 }
309 
310 void PPCInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
311                                MachineBasicBlock::iterator I, DebugLoc DL,
312                                unsigned DestReg, unsigned SrcReg,
313                                bool KillSrc) const {
314   unsigned Opc;
315   if (PPC::GPRCRegClass.contains(DestReg, SrcReg))
316     Opc = PPC::OR;
317   else if (PPC::G8RCRegClass.contains(DestReg, SrcReg))
318     Opc = PPC::OR8;
319   else if (PPC::F4RCRegClass.contains(DestReg, SrcReg))
320     Opc = PPC::FMR;
321   else if (PPC::CRRCRegClass.contains(DestReg, SrcReg))
322     Opc = PPC::MCRF;
323   else if (PPC::VRRCRegClass.contains(DestReg, SrcReg))
324     Opc = PPC::VOR;
325   else if (PPC::CRBITRCRegClass.contains(DestReg, SrcReg))
326     Opc = PPC::CROR;
327   else
328     llvm_unreachable("Impossible reg-to-reg copy");
329 
330   const MCInstrDesc &MCID = get(Opc);
331   if (MCID.getNumOperands() == 3)
332     BuildMI(MBB, I, DL, MCID, DestReg)
333       .addReg(SrcReg).addReg(SrcReg, getKillRegState(KillSrc));
334   else
335     BuildMI(MBB, I, DL, MCID, DestReg).addReg(SrcReg, getKillRegState(KillSrc));
336 }
337 
338 bool
339 PPCInstrInfo::StoreRegToStackSlot(MachineFunction &MF,
340                                   unsigned SrcReg, bool isKill,
341                                   int FrameIdx,
342                                   const TargetRegisterClass *RC,
343                                   SmallVectorImpl<MachineInstr*> &NewMIs) const{
344   DebugLoc DL;
345   if (PPC::GPRCRegisterClass->hasSubClassEq(RC)) {
346     if (SrcReg != PPC::LR) {
347       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STW))
348                                          .addReg(SrcReg,
349                                                  getKillRegState(isKill)),
350                                          FrameIdx));
351     } else {
352       // FIXME: this spills LR immediately to memory in one step.  To do this,
353       // we use R11, which we know cannot be used in the prolog/epilog.  This is
354       // a hack.
355       NewMIs.push_back(BuildMI(MF, DL, get(PPC::MFLR), PPC::R11));
356       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STW))
357                                          .addReg(PPC::R11,
358                                                  getKillRegState(isKill)),
359                                          FrameIdx));
360     }
361   } else if (PPC::G8RCRegisterClass->hasSubClassEq(RC)) {
362     if (SrcReg != PPC::LR8) {
363       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STD))
364                                          .addReg(SrcReg,
365                                                  getKillRegState(isKill)),
366                                          FrameIdx));
367     } else {
368       // FIXME: this spills LR immediately to memory in one step.  To do this,
369       // we use R11, which we know cannot be used in the prolog/epilog.  This is
370       // a hack.
371       NewMIs.push_back(BuildMI(MF, DL, get(PPC::MFLR8), PPC::X11));
372       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STD))
373                                          .addReg(PPC::X11,
374                                                  getKillRegState(isKill)),
375                                          FrameIdx));
376     }
377   } else if (PPC::F8RCRegisterClass->hasSubClassEq(RC)) {
378     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STFD))
379                                        .addReg(SrcReg,
380                                                getKillRegState(isKill)),
381                                        FrameIdx));
382   } else if (PPC::F4RCRegisterClass->hasSubClassEq(RC)) {
383     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STFS))
384                                        .addReg(SrcReg,
385                                                getKillRegState(isKill)),
386                                        FrameIdx));
387   } else if (PPC::CRRCRegisterClass->hasSubClassEq(RC)) {
388     if ((EnablePPC32RS && !TM.getSubtargetImpl()->isPPC64()) ||
389         (EnablePPC64RS && TM.getSubtargetImpl()->isPPC64())) {
390       // FIXME (64-bit): Enable
391       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::SPILL_CR))
392                                          .addReg(SrcReg,
393                                                  getKillRegState(isKill)),
394                                          FrameIdx));
395       return true;
396     } else {
397       // FIXME: We need a scatch reg here.  The trouble with using R0 is that
398       // it's possible for the stack frame to be so big the save location is
399       // out of range of immediate offsets, necessitating another register.
400       // We hack this on Darwin by reserving R2.  It's probably broken on Linux
401       // at the moment.
402 
403       // We need to store the CR in the low 4-bits of the saved value.  First,
404       // issue a MFCR to save all of the CRBits.
405       unsigned ScratchReg = TM.getSubtargetImpl()->isDarwinABI() ?
406                                                            PPC::R2 : PPC::R0;
407       NewMIs.push_back(BuildMI(MF, DL, get(PPC::MFCRpseud), ScratchReg)
408                                .addReg(SrcReg, getKillRegState(isKill)));
409 
410       // If the saved register wasn't CR0, shift the bits left so that they are
411       // in CR0's slot.
412       if (SrcReg != PPC::CR0) {
413         unsigned ShiftBits = getPPCRegisterNumbering(SrcReg)*4;
414         // rlwinm scratch, scratch, ShiftBits, 0, 31.
415         NewMIs.push_back(BuildMI(MF, DL, get(PPC::RLWINM), ScratchReg)
416                        .addReg(ScratchReg).addImm(ShiftBits)
417                        .addImm(0).addImm(31));
418       }
419 
420       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STW))
421                                          .addReg(ScratchReg,
422                                                  getKillRegState(isKill)),
423                                          FrameIdx));
424     }
425   } else if (PPC::CRBITRCRegisterClass->hasSubClassEq(RC)) {
426     // FIXME: We use CRi here because there is no mtcrf on a bit. Since the
427     // backend currently only uses CR1EQ as an individual bit, this should
428     // not cause any bug. If we need other uses of CR bits, the following
429     // code may be invalid.
430     unsigned Reg = 0;
431     if (SrcReg == PPC::CR0LT || SrcReg == PPC::CR0GT ||
432         SrcReg == PPC::CR0EQ || SrcReg == PPC::CR0UN)
433       Reg = PPC::CR0;
434     else if (SrcReg == PPC::CR1LT || SrcReg == PPC::CR1GT ||
435              SrcReg == PPC::CR1EQ || SrcReg == PPC::CR1UN)
436       Reg = PPC::CR1;
437     else if (SrcReg == PPC::CR2LT || SrcReg == PPC::CR2GT ||
438              SrcReg == PPC::CR2EQ || SrcReg == PPC::CR2UN)
439       Reg = PPC::CR2;
440     else if (SrcReg == PPC::CR3LT || SrcReg == PPC::CR3GT ||
441              SrcReg == PPC::CR3EQ || SrcReg == PPC::CR3UN)
442       Reg = PPC::CR3;
443     else if (SrcReg == PPC::CR4LT || SrcReg == PPC::CR4GT ||
444              SrcReg == PPC::CR4EQ || SrcReg == PPC::CR4UN)
445       Reg = PPC::CR4;
446     else if (SrcReg == PPC::CR5LT || SrcReg == PPC::CR5GT ||
447              SrcReg == PPC::CR5EQ || SrcReg == PPC::CR5UN)
448       Reg = PPC::CR5;
449     else if (SrcReg == PPC::CR6LT || SrcReg == PPC::CR6GT ||
450              SrcReg == PPC::CR6EQ || SrcReg == PPC::CR6UN)
451       Reg = PPC::CR6;
452     else if (SrcReg == PPC::CR7LT || SrcReg == PPC::CR7GT ||
453              SrcReg == PPC::CR7EQ || SrcReg == PPC::CR7UN)
454       Reg = PPC::CR7;
455 
456     return StoreRegToStackSlot(MF, Reg, isKill, FrameIdx,
457                                PPC::CRRCRegisterClass, NewMIs);
458 
459   } else if (PPC::VRRCRegisterClass->hasSubClassEq(RC)) {
460     // We don't have indexed addressing for vector loads.  Emit:
461     // R0 = ADDI FI#
462     // STVX VAL, 0, R0
463     //
464     // FIXME: We use R0 here, because it isn't available for RA.
465     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::ADDI), PPC::R0),
466                                        FrameIdx, 0, 0));
467     NewMIs.push_back(BuildMI(MF, DL, get(PPC::STVX))
468                      .addReg(SrcReg, getKillRegState(isKill))
469                      .addReg(PPC::R0)
470                      .addReg(PPC::R0));
471   } else {
472     llvm_unreachable("Unknown regclass!");
473   }
474 
475   return false;
476 }
477 
478 void
479 PPCInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
480                                   MachineBasicBlock::iterator MI,
481                                   unsigned SrcReg, bool isKill, int FrameIdx,
482                                   const TargetRegisterClass *RC,
483                                   const TargetRegisterInfo *TRI) const {
484   MachineFunction &MF = *MBB.getParent();
485   SmallVector<MachineInstr*, 4> NewMIs;
486 
487   if (StoreRegToStackSlot(MF, SrcReg, isKill, FrameIdx, RC, NewMIs)) {
488     PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
489     FuncInfo->setSpillsCR();
490   }
491 
492   for (unsigned i = 0, e = NewMIs.size(); i != e; ++i)
493     MBB.insert(MI, NewMIs[i]);
494 
495   const MachineFrameInfo &MFI = *MF.getFrameInfo();
496   MachineMemOperand *MMO =
497     MF.getMachineMemOperand(
498                 MachinePointerInfo(PseudoSourceValue::getFixedStack(FrameIdx)),
499                             MachineMemOperand::MOStore,
500                             MFI.getObjectSize(FrameIdx),
501                             MFI.getObjectAlignment(FrameIdx));
502   NewMIs.back()->addMemOperand(MF, MMO);
503 }
504 
505 void
506 PPCInstrInfo::LoadRegFromStackSlot(MachineFunction &MF, DebugLoc DL,
507                                    unsigned DestReg, int FrameIdx,
508                                    const TargetRegisterClass *RC,
509                                    SmallVectorImpl<MachineInstr*> &NewMIs)const{
510   if (PPC::GPRCRegisterClass->hasSubClassEq(RC)) {
511     if (DestReg != PPC::LR) {
512       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LWZ),
513                                                  DestReg), FrameIdx));
514     } else {
515       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LWZ),
516                                                  PPC::R11), FrameIdx));
517       NewMIs.push_back(BuildMI(MF, DL, get(PPC::MTLR)).addReg(PPC::R11));
518     }
519   } else if (PPC::G8RCRegisterClass->hasSubClassEq(RC)) {
520     if (DestReg != PPC::LR8) {
521       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LD), DestReg),
522                                          FrameIdx));
523     } else {
524       NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LD),
525                                                  PPC::R11), FrameIdx));
526       NewMIs.push_back(BuildMI(MF, DL, get(PPC::MTLR8)).addReg(PPC::R11));
527     }
528   } else if (PPC::F8RCRegisterClass->hasSubClassEq(RC)) {
529     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LFD), DestReg),
530                                        FrameIdx));
531   } else if (PPC::F4RCRegisterClass->hasSubClassEq(RC)) {
532     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LFS), DestReg),
533                                        FrameIdx));
534   } else if (PPC::CRRCRegisterClass->hasSubClassEq(RC)) {
535     // FIXME: We need a scatch reg here.  The trouble with using R0 is that
536     // it's possible for the stack frame to be so big the save location is
537     // out of range of immediate offsets, necessitating another register.
538     // We hack this on Darwin by reserving R2.  It's probably broken on Linux
539     // at the moment.
540     unsigned ScratchReg = TM.getSubtargetImpl()->isDarwinABI() ?
541                                                           PPC::R2 : PPC::R0;
542     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LWZ),
543                                        ScratchReg), FrameIdx));
544 
545     // If the reloaded register isn't CR0, shift the bits right so that they are
546     // in the right CR's slot.
547     if (DestReg != PPC::CR0) {
548       unsigned ShiftBits = getPPCRegisterNumbering(DestReg)*4;
549       // rlwinm r11, r11, 32-ShiftBits, 0, 31.
550       NewMIs.push_back(BuildMI(MF, DL, get(PPC::RLWINM), ScratchReg)
551                     .addReg(ScratchReg).addImm(32-ShiftBits).addImm(0)
552                     .addImm(31));
553     }
554 
555     NewMIs.push_back(BuildMI(MF, DL, get(PPC::MTCRF), DestReg)
556                      .addReg(ScratchReg));
557   } else if (PPC::CRBITRCRegisterClass->hasSubClassEq(RC)) {
558 
559     unsigned Reg = 0;
560     if (DestReg == PPC::CR0LT || DestReg == PPC::CR0GT ||
561         DestReg == PPC::CR0EQ || DestReg == PPC::CR0UN)
562       Reg = PPC::CR0;
563     else if (DestReg == PPC::CR1LT || DestReg == PPC::CR1GT ||
564              DestReg == PPC::CR1EQ || DestReg == PPC::CR1UN)
565       Reg = PPC::CR1;
566     else if (DestReg == PPC::CR2LT || DestReg == PPC::CR2GT ||
567              DestReg == PPC::CR2EQ || DestReg == PPC::CR2UN)
568       Reg = PPC::CR2;
569     else if (DestReg == PPC::CR3LT || DestReg == PPC::CR3GT ||
570              DestReg == PPC::CR3EQ || DestReg == PPC::CR3UN)
571       Reg = PPC::CR3;
572     else if (DestReg == PPC::CR4LT || DestReg == PPC::CR4GT ||
573              DestReg == PPC::CR4EQ || DestReg == PPC::CR4UN)
574       Reg = PPC::CR4;
575     else if (DestReg == PPC::CR5LT || DestReg == PPC::CR5GT ||
576              DestReg == PPC::CR5EQ || DestReg == PPC::CR5UN)
577       Reg = PPC::CR5;
578     else if (DestReg == PPC::CR6LT || DestReg == PPC::CR6GT ||
579              DestReg == PPC::CR6EQ || DestReg == PPC::CR6UN)
580       Reg = PPC::CR6;
581     else if (DestReg == PPC::CR7LT || DestReg == PPC::CR7GT ||
582              DestReg == PPC::CR7EQ || DestReg == PPC::CR7UN)
583       Reg = PPC::CR7;
584 
585     return LoadRegFromStackSlot(MF, DL, Reg, FrameIdx,
586                                 PPC::CRRCRegisterClass, NewMIs);
587 
588   } else if (PPC::VRRCRegisterClass->hasSubClassEq(RC)) {
589     // We don't have indexed addressing for vector loads.  Emit:
590     // R0 = ADDI FI#
591     // Dest = LVX 0, R0
592     //
593     // FIXME: We use R0 here, because it isn't available for RA.
594     NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::ADDI), PPC::R0),
595                                        FrameIdx, 0, 0));
596     NewMIs.push_back(BuildMI(MF, DL, get(PPC::LVX),DestReg).addReg(PPC::R0)
597                      .addReg(PPC::R0));
598   } else {
599     llvm_unreachable("Unknown regclass!");
600   }
601 }
602 
603 void
604 PPCInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
605                                    MachineBasicBlock::iterator MI,
606                                    unsigned DestReg, int FrameIdx,
607                                    const TargetRegisterClass *RC,
608                                    const TargetRegisterInfo *TRI) const {
609   MachineFunction &MF = *MBB.getParent();
610   SmallVector<MachineInstr*, 4> NewMIs;
611   DebugLoc DL;
612   if (MI != MBB.end()) DL = MI->getDebugLoc();
613   LoadRegFromStackSlot(MF, DL, DestReg, FrameIdx, RC, NewMIs);
614   for (unsigned i = 0, e = NewMIs.size(); i != e; ++i)
615     MBB.insert(MI, NewMIs[i]);
616 
617   const MachineFrameInfo &MFI = *MF.getFrameInfo();
618   MachineMemOperand *MMO =
619     MF.getMachineMemOperand(
620                 MachinePointerInfo(PseudoSourceValue::getFixedStack(FrameIdx)),
621                             MachineMemOperand::MOLoad,
622                             MFI.getObjectSize(FrameIdx),
623                             MFI.getObjectAlignment(FrameIdx));
624   NewMIs.back()->addMemOperand(MF, MMO);
625 }
626 
627 MachineInstr*
628 PPCInstrInfo::emitFrameIndexDebugValue(MachineFunction &MF,
629                                        int FrameIx, uint64_t Offset,
630                                        const MDNode *MDPtr,
631                                        DebugLoc DL) const {
632   MachineInstrBuilder MIB = BuildMI(MF, DL, get(PPC::DBG_VALUE));
633   addFrameReference(MIB, FrameIx, 0, false).addImm(Offset).addMetadata(MDPtr);
634   return &*MIB;
635 }
636 
637 bool PPCInstrInfo::
638 ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const {
639   assert(Cond.size() == 2 && "Invalid PPC branch opcode!");
640   // Leave the CR# the same, but invert the condition.
641   Cond[0].setImm(PPC::InvertPredicate((PPC::Predicate)Cond[0].getImm()));
642   return false;
643 }
644 
645 /// GetInstSize - Return the number of bytes of code the specified
646 /// instruction may be.  This returns the maximum number of bytes.
647 ///
648 unsigned PPCInstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const {
649   switch (MI->getOpcode()) {
650   case PPC::INLINEASM: {       // Inline Asm: Variable size.
651     const MachineFunction *MF = MI->getParent()->getParent();
652     const char *AsmStr = MI->getOperand(0).getSymbolName();
653     return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo());
654   }
655   case PPC::PROLOG_LABEL:
656   case PPC::EH_LABEL:
657   case PPC::GC_LABEL:
658   case PPC::DBG_VALUE:
659     return 0;
660   default:
661     return 4; // PowerPC instructions are all 4 bytes
662   }
663 }
664