lib/Target/AMDGPU/R600ControlFlowFinalizer.cpp

   1 //===-- R600ControlFlowFinalizer.cpp - Finalize Control Flow Inst----------===//
   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 /// \file
  11 /// This pass compute turns all control flow pseudo instructions into native one
  12 /// computing their address on the fly ; it also sets STACK_SIZE info.
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Support/Debug.h"
  16 #include "AMDGPU.h"
  17 #include "AMDGPUSubtarget.h"
  18 #include "R600Defines.h"
  19 #include "R600InstrInfo.h"
  20 #include "R600MachineFunctionInfo.h"
  21 #include "R600RegisterInfo.h"
  22 #include "llvm/CodeGen/MachineFunctionPass.h"
  23 #include "llvm/CodeGen/MachineInstrBuilder.h"
  24 #include "llvm/CodeGen/MachineRegisterInfo.h"
  25 #include "llvm/Support/raw_ostream.h"
  26
  27 using namespace llvm;
  28
  29 #define DEBUG_TYPE "r600cf"
  30
  31 namespace {
  32
  33 struct CFStack {
  34
  35   enum StackItem {
  36     ENTRY = 0,
  37     SUB_ENTRY = 1,
  38     FIRST_NON_WQM_PUSH = 2,
  39     FIRST_NON_WQM_PUSH_W_FULL_ENTRY = 3
  40   };
  41
  42   const AMDGPUSubtarget *ST;
  43   std::vector<StackItem> BranchStack;
  44   std::vector<StackItem> LoopStack;
  45   unsigned MaxStackSize;
  46   unsigned CurrentEntries;
  47   unsigned CurrentSubEntries;
  48
  49   CFStack(const AMDGPUSubtarget *st, unsigned ShaderType) : ST(st),
  50       // We need to reserve a stack entry for CALL_FS in vertex shaders.
  51       MaxStackSize(ShaderType == ShaderType::VERTEX ? 1 : 0),
  52       CurrentEntries(0), CurrentSubEntries(0) { }
  53
  54   unsigned getLoopDepth();
  55   bool branchStackContains(CFStack::StackItem);
  56   bool requiresWorkAroundForInst(unsigned Opcode);
  57   unsigned getSubEntrySize(CFStack::StackItem Item);
  58   void updateMaxStackSize();
  59   void pushBranch(unsigned Opcode, bool isWQM = false);
  60   void pushLoop();
  61   void popBranch();
  62   void popLoop();
  63 };
  64
  65 unsigned CFStack::getLoopDepth() {
  66   return LoopStack.size();
  67 }
  68
  69 bool CFStack::branchStackContains(CFStack::StackItem Item) {
  70   for (std::vector<CFStack::StackItem>::const_iterator I = BranchStack.begin(),
  71        E = BranchStack.end(); I != E; ++I) {
  72     if (*I == Item)
  73       return true;
  74   }
  75   return false;
  76 }
  77
  78 bool CFStack::requiresWorkAroundForInst(unsigned Opcode) {
  79   if (Opcode == AMDGPU::CF_ALU_PUSH_BEFORE && ST->hasCaymanISA() &&
  80       getLoopDepth() > 1)
  81     return true;
  82
  83   if (!ST->hasCFAluBug())
  84     return false;
  85
  86   switch(Opcode) {
  87   default: return false;
  88   case AMDGPU::CF_ALU_PUSH_BEFORE:
  89   case AMDGPU::CF_ALU_ELSE_AFTER:
  90   case AMDGPU::CF_ALU_BREAK:
  91   case AMDGPU::CF_ALU_CONTINUE:
  92     if (CurrentSubEntries == 0)
  93       return false;
  94     if (ST->getWavefrontSize() == 64) {
  95       // We are being conservative here.  We only require this work-around if
  96       // CurrentSubEntries > 3 &&
  97       // (CurrentSubEntries % 4 == 3 || CurrentSubEntries % 4 == 0)
  98       //
  99       // We have to be conservative, because we don't know for certain that
 100       // our stack allocation algorithm for Evergreen/NI is correct.  Applying this
 101       // work-around when CurrentSubEntries > 3 allows us to over-allocate stack
 102       // resources without any problems.
 103       return CurrentSubEntries > 3;
 104     } else {
 105       assert(ST->getWavefrontSize() == 32);
 106       // We are being conservative here.  We only require the work-around if
 107       // CurrentSubEntries > 7 &&
 108       // (CurrentSubEntries % 8 == 7 || CurrentSubEntries % 8 == 0)
 109       // See the comment on the wavefront size == 64 case for why we are
 110       // being conservative.
 111       return CurrentSubEntries > 7;
 112     }
 113   }
 114 }
 115
 116 unsigned CFStack::getSubEntrySize(CFStack::StackItem Item) {
 117   switch(Item) {
 118   default:
 119     return 0;
 120   case CFStack::FIRST_NON_WQM_PUSH:
 121   assert(!ST->hasCaymanISA());
 122   if (ST->getGeneration() <= AMDGPUSubtarget::R700) {
 123     // +1 For the push operation.
 124     // +2 Extra space required.
 125     return 3;
 126   } else {
 127     // Some documentation says that this is not necessary on Evergreen,
 128     // but experimentation has show that we need to allocate 1 extra
 129     // sub-entry for the first non-WQM push.
 130     // +1 For the push operation.
 131     // +1 Extra space required.
 132     return 2;
 133   }
 134   case CFStack::FIRST_NON_WQM_PUSH_W_FULL_ENTRY:
 135     assert(ST->getGeneration() >= AMDGPUSubtarget::EVERGREEN);
 136     // +1 For the push operation.
 137     // +1 Extra space required.
 138     return 2;
 139   case CFStack::SUB_ENTRY:
 140     return 1;
 141   }
 142 }
 143
 144 void CFStack::updateMaxStackSize() {
 145   unsigned CurrentStackSize = CurrentEntries +
 146                               (RoundUpToAlignment(CurrentSubEntries, 4) / 4);
 147   MaxStackSize = std::max(CurrentStackSize, MaxStackSize);
 148 }
 149
 150 void CFStack::pushBranch(unsigned Opcode, bool isWQM) {
 151   CFStack::StackItem Item = CFStack::ENTRY;
 152   switch(Opcode) {
 153   case AMDGPU::CF_PUSH_EG:
 154   case AMDGPU::CF_ALU_PUSH_BEFORE:
 155     if (!isWQM) {
 156       if (!ST->hasCaymanISA() &&
 157           !branchStackContains(CFStack::FIRST_NON_WQM_PUSH))
 158         Item = CFStack::FIRST_NON_WQM_PUSH;  // May not be required on Evergreen/NI
 159                                              // See comment in
 160                                              // CFStack::getSubEntrySize()
 161       else if (CurrentEntries > 0 &&
 162                ST->getGeneration() > AMDGPUSubtarget::EVERGREEN &&
 163                !ST->hasCaymanISA() &&
 164                !branchStackContains(CFStack::FIRST_NON_WQM_PUSH_W_FULL_ENTRY))
 165         Item = CFStack::FIRST_NON_WQM_PUSH_W_FULL_ENTRY;
 166       else
 167         Item = CFStack::SUB_ENTRY;
 168     } else
 169       Item = CFStack::ENTRY;
 170     break;
 171   }
 172   BranchStack.push_back(Item);
 173   if (Item == CFStack::ENTRY)
 174     CurrentEntries++;
 175   else
 176     CurrentSubEntries += getSubEntrySize(Item);
 177   updateMaxStackSize();
 178 }
 179
 180 void CFStack::pushLoop() {
 181   LoopStack.push_back(CFStack::ENTRY);
 182   CurrentEntries++;
 183   updateMaxStackSize();
 184 }
 185
 186 void CFStack::popBranch() {
 187   CFStack::StackItem Top = BranchStack.back();
 188   if (Top == CFStack::ENTRY)
 189     CurrentEntries--;
 190   else
 191     CurrentSubEntries-= getSubEntrySize(Top);
 192   BranchStack.pop_back();
 193 }
 194
 195 void CFStack::popLoop() {
 196   CurrentEntries--;
 197   LoopStack.pop_back();
 198 }
 199
 200 class R600ControlFlowFinalizer : public MachineFunctionPass {
 201
 202 private:
 203   typedef std::pair<MachineInstr *, std::vector<MachineInstr *> > ClauseFile;
 204
 205   enum ControlFlowInstruction {
 206     CF_TC,
 207     CF_VC,
 208     CF_CALL_FS,
 209     CF_WHILE_LOOP,
 210     CF_END_LOOP,
 211     CF_LOOP_BREAK,
 212     CF_LOOP_CONTINUE,
 213     CF_JUMP,
 214     CF_ELSE,
 215     CF_POP,
 216     CF_END
 217   };
 218
 219   static char ID;
 220   const R600InstrInfo *TII;
 221   const R600RegisterInfo *TRI;
 222   unsigned MaxFetchInst;
 223   const AMDGPUSubtarget *ST;
 224
 225   bool IsTrivialInst(MachineInstr *MI) const {
 226     switch (MI->getOpcode()) {
 227     case AMDGPU::KILL:
 228     case AMDGPU::RETURN:
 229       return true;
 230     default:
 231       return false;
 232     }
 233   }
 234
 235   const MCInstrDesc &getHWInstrDesc(ControlFlowInstruction CFI) const {
 236     unsigned Opcode = 0;
 237     bool isEg = (ST->getGeneration() >= AMDGPUSubtarget::EVERGREEN);
 238     switch (CFI) {
 239     case CF_TC:
 240       Opcode = isEg ? AMDGPU::CF_TC_EG : AMDGPU::CF_TC_R600;
 241       break;
 242     case CF_VC:
 243       Opcode = isEg ? AMDGPU::CF_VC_EG : AMDGPU::CF_VC_R600;
 244       break;
 245     case CF_CALL_FS:
 246       Opcode = isEg ? AMDGPU::CF_CALL_FS_EG : AMDGPU::CF_CALL_FS_R600;
 247       break;
 248     case CF_WHILE_LOOP:
 249       Opcode = isEg ? AMDGPU::WHILE_LOOP_EG : AMDGPU::WHILE_LOOP_R600;
 250       break;
 251     case CF_END_LOOP:
 252       Opcode = isEg ? AMDGPU::END_LOOP_EG : AMDGPU::END_LOOP_R600;
 253       break;
 254     case CF_LOOP_BREAK:
 255       Opcode = isEg ? AMDGPU::LOOP_BREAK_EG : AMDGPU::LOOP_BREAK_R600;
 256       break;
 257     case CF_LOOP_CONTINUE:
 258       Opcode = isEg ? AMDGPU::CF_CONTINUE_EG : AMDGPU::CF_CONTINUE_R600;
 259       break;
 260     case CF_JUMP:
 261       Opcode = isEg ? AMDGPU::CF_JUMP_EG : AMDGPU::CF_JUMP_R600;
 262       break;
 263     case CF_ELSE:
 264       Opcode = isEg ? AMDGPU::CF_ELSE_EG : AMDGPU::CF_ELSE_R600;
 265       break;
 266     case CF_POP:
 267       Opcode = isEg ? AMDGPU::POP_EG : AMDGPU::POP_R600;
 268       break;
 269     case CF_END:
 270       if (ST->hasCaymanISA()) {
 271         Opcode = AMDGPU::CF_END_CM;
 272         break;
 273       }
 274       Opcode = isEg ? AMDGPU::CF_END_EG : AMDGPU::CF_END_R600;
 275       break;
 276     }
 277     assert (Opcode && "No opcode selected");
 278     return TII->get(Opcode);
 279   }
 280
 281   bool isCompatibleWithClause(const MachineInstr *MI,
 282       std::set<unsigned> &DstRegs) const {
 283     unsigned DstMI, SrcMI;
 284     for (MachineInstr::const_mop_iterator I = MI->operands_begin(),
 285         E = MI->operands_end(); I != E; ++I) {
 286       const MachineOperand &MO = *I;
 287       if (!MO.isReg())
 288         continue;
 289       if (MO.isDef()) {
 290         unsigned Reg = MO.getReg();
 291         if (AMDGPU::R600_Reg128RegClass.contains(Reg))
 292           DstMI = Reg;
 293         else
 294           DstMI = TRI->getMatchingSuperReg(Reg,
 295               TRI->getSubRegFromChannel(TRI->getHWRegChan(Reg)),
 296               &AMDGPU::R600_Reg128RegClass);
 297       }
 298       if (MO.isUse()) {
 299         unsigned Reg = MO.getReg();
 300         if (AMDGPU::R600_Reg128RegClass.contains(Reg))
 301           SrcMI = Reg;
 302         else
 303           SrcMI = TRI->getMatchingSuperReg(Reg,
 304               TRI->getSubRegFromChannel(TRI->getHWRegChan(Reg)),
 305               &AMDGPU::R600_Reg128RegClass);
 306       }
 307     }
 308     if ((DstRegs.find(SrcMI) == DstRegs.end())) {
 309       DstRegs.insert(DstMI);
 310       return true;
 311     } else
 312       return false;
 313   }
 314
 315   ClauseFile
 316   MakeFetchClause(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I)
 317       const {
 318     MachineBasicBlock::iterator ClauseHead = I;
 319     std::vector<MachineInstr *> ClauseContent;
 320     unsigned AluInstCount = 0;
 321     bool IsTex = TII->usesTextureCache(ClauseHead);
 322     std::set<unsigned> DstRegs;
 323     for (MachineBasicBlock::iterator E = MBB.end(); I != E; ++I) {
 324       if (IsTrivialInst(I))
 325         continue;
 326       if (AluInstCount >= MaxFetchInst)
 327         break;
 328       if ((IsTex && !TII->usesTextureCache(I)) ||
 329           (!IsTex && !TII->usesVertexCache(I)))
 330         break;
 331       if (!isCompatibleWithClause(I, DstRegs))
 332         break;
 333       AluInstCount ++;
 334       ClauseContent.push_back(I);
 335     }
 336     MachineInstr *MIb = BuildMI(MBB, ClauseHead, MBB.findDebugLoc(ClauseHead),
 337         getHWInstrDesc(IsTex?CF_TC:CF_VC))
 338         .addImm(0) // ADDR
 339         .addImm(AluInstCount - 1); // COUNT
 340     return ClauseFile(MIb, std::move(ClauseContent));
 341   }
 342
 343   void getLiteral(MachineInstr *MI, std::vector<int64_t> &Lits) const {
 344     static const unsigned LiteralRegs[] = {
 345       AMDGPU::ALU_LITERAL_X,
 346       AMDGPU::ALU_LITERAL_Y,
 347       AMDGPU::ALU_LITERAL_Z,
 348       AMDGPU::ALU_LITERAL_W
 349     };
 350     const SmallVector<std::pair<MachineOperand *, int64_t>, 3 > Srcs =
 351         TII->getSrcs(MI);
 352     for (unsigned i = 0, e = Srcs.size(); i < e; ++i) {
 353       if (Srcs[i].first->getReg() != AMDGPU::ALU_LITERAL_X)
 354         continue;
 355       int64_t Imm = Srcs[i].second;
 356       std::vector<int64_t>::iterator It =
 357           std::find(Lits.begin(), Lits.end(), Imm);
 358       if (It != Lits.end()) {
 359         unsigned Index = It - Lits.begin();
 360         Srcs[i].first->setReg(LiteralRegs[Index]);
 361       } else {
 362         assert(Lits.size() < 4 && "Too many literals in Instruction Group");
 363         Srcs[i].first->setReg(LiteralRegs[Lits.size()]);
 364         Lits.push_back(Imm);
 365       }
 366     }
 367   }
 368
 369   MachineBasicBlock::iterator insertLiterals(
 370       MachineBasicBlock::iterator InsertPos,
 371       const std::vector<unsigned> &Literals) const {
 372     MachineBasicBlock *MBB = InsertPos->getParent();
 373     for (unsigned i = 0, e = Literals.size(); i < e; i+=2) {
 374       unsigned LiteralPair0 = Literals[i];
 375       unsigned LiteralPair1 = (i + 1 < e)?Literals[i + 1]:0;
 376       InsertPos = BuildMI(MBB, InsertPos->getDebugLoc(),
 377           TII->get(AMDGPU::LITERALS))
 378           .addImm(LiteralPair0)
 379           .addImm(LiteralPair1);
 380     }
 381     return InsertPos;
 382   }
 383
 384   ClauseFile
 385   MakeALUClause(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I)
 386       const {
 387     MachineBasicBlock::iterator ClauseHead = I;
 388     std::vector<MachineInstr *> ClauseContent;
 389     I++;
 390     for (MachineBasicBlock::instr_iterator E = MBB.instr_end(); I != E;) {
 391       if (IsTrivialInst(I)) {
 392         ++I;
 393         continue;
 394       }
 395       if (!I->isBundle() && !TII->isALUInstr(I->getOpcode()))
 396         break;
 397       std::vector<int64_t> Literals;
 398       if (I->isBundle()) {
 399         MachineInstr *DeleteMI = I;
 400         MachineBasicBlock::instr_iterator BI = I.getInstrIterator();
 401         while (++BI != E && BI->isBundledWithPred()) {
 402           BI->unbundleFromPred();
 403           for (unsigned i = 0, e = BI->getNumOperands(); i != e; ++i) {
 404             MachineOperand &MO = BI->getOperand(i);
 405             if (MO.isReg() && MO.isInternalRead())
 406               MO.setIsInternalRead(false);
 407           }
 408           getLiteral(&*BI, Literals);
 409           ClauseContent.push_back(&*BI);
 410         }
 411         I = BI;
 412         DeleteMI->eraseFromParent();
 413       } else {
 414         getLiteral(I, Literals);
 415         ClauseContent.push_back(I);
 416         I++;
 417       }
 418       for (unsigned i = 0, e = Literals.size(); i < e; i+=2) {
 419         unsigned literal0 = Literals[i];
 420         unsigned literal2 = (i + 1 < e)?Literals[i + 1]:0;
 421         MachineInstr *MILit = BuildMI(MBB, I, I->getDebugLoc(),
 422             TII->get(AMDGPU::LITERALS))
 423             .addImm(literal0)
 424             .addImm(literal2);
 425         ClauseContent.push_back(MILit);
 426       }
 427     }
 428     assert(ClauseContent.size() < 128 && "ALU clause is too big");
 429     ClauseHead->getOperand(7).setImm(ClauseContent.size() - 1);
 430     return ClauseFile(ClauseHead, std::move(ClauseContent));
 431   }
 432
 433   void
 434   EmitFetchClause(MachineBasicBlock::iterator InsertPos, ClauseFile &Clause,
 435       unsigned &CfCount) {
 436     CounterPropagateAddr(Clause.first, CfCount);
 437     MachineBasicBlock *BB = Clause.first->getParent();
 438     BuildMI(BB, InsertPos->getDebugLoc(), TII->get(AMDGPU::FETCH_CLAUSE))
 439         .addImm(CfCount);
 440     for (unsigned i = 0, e = Clause.second.size(); i < e; ++i) {
 441       BB->splice(InsertPos, BB, Clause.second[i]);
 442     }
 443     CfCount += 2 * Clause.second.size();
 444   }
 445
 446   void
 447   EmitALUClause(MachineBasicBlock::iterator InsertPos, ClauseFile &Clause,
 448       unsigned &CfCount) {
 449     Clause.first->getOperand(0).setImm(0);
 450     CounterPropagateAddr(Clause.first, CfCount);
 451     MachineBasicBlock *BB = Clause.first->getParent();
 452     BuildMI(BB, InsertPos->getDebugLoc(), TII->get(AMDGPU::ALU_CLAUSE))
 453         .addImm(CfCount);
 454     for (unsigned i = 0, e = Clause.second.size(); i < e; ++i) {
 455       BB->splice(InsertPos, BB, Clause.second[i]);
 456     }
 457     CfCount += Clause.second.size();
 458   }
 459
 460   void CounterPropagateAddr(MachineInstr *MI, unsigned Addr) const {
 461     MI->getOperand(0).setImm(Addr + MI->getOperand(0).getImm());
 462   }
 463   void CounterPropagateAddr(const std::set<MachineInstr *> &MIs,
 464                             unsigned Addr) const {
 465     for (MachineInstr *MI : MIs) {
 466       CounterPropagateAddr(MI, Addr);
 467     }
 468   }
 469
 470 public:
 471   R600ControlFlowFinalizer(TargetMachine &tm)
 472       : MachineFunctionPass(ID), TII(nullptr), TRI(nullptr), ST(nullptr) {}
 473
 474   bool runOnMachineFunction(MachineFunction &MF) override {
 475     ST = &MF.getSubtarget<AMDGPUSubtarget>();
 476     MaxFetchInst = ST->getTexVTXClauseSize();
 477     TII = static_cast<const R600InstrInfo *>(ST->getInstrInfo());
 478     TRI = static_cast<const R600RegisterInfo *>(ST->getRegisterInfo());
 479     R600MachineFunctionInfo *MFI = MF.getInfo<R600MachineFunctionInfo>();
 480
 481     CFStack CFStack(ST, MFI->getShaderType());
 482     for (MachineFunction::iterator MB = MF.begin(), ME = MF.end(); MB != ME;
 483         ++MB) {
 484       MachineBasicBlock &MBB = *MB;
 485       unsigned CfCount = 0;
 486       std::vector<std::pair<unsigned, std::set<MachineInstr *> > > LoopStack;
 487       std::vector<MachineInstr * > IfThenElseStack;
 488       if (MFI->getShaderType() == ShaderType::VERTEX) {
 489         BuildMI(MBB, MBB.begin(), MBB.findDebugLoc(MBB.begin()),
 490             getHWInstrDesc(CF_CALL_FS));
 491         CfCount++;
 492       }
 493       std::vector<ClauseFile> FetchClauses, AluClauses;
 494       std::vector<MachineInstr *> LastAlu(1);
 495       std::vector<MachineInstr *> ToPopAfter;
 496
 497       for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
 498           I != E;) {
 499         if (TII->usesTextureCache(I) || TII->usesVertexCache(I)) {
 500           DEBUG(dbgs() << CfCount << ":"; I->dump(););
 501           FetchClauses.push_back(MakeFetchClause(MBB, I));
 502           CfCount++;
 503           LastAlu.back() = nullptr;
 504           continue;
 505         }
 506
 507         MachineBasicBlock::iterator MI = I;
 508         if (MI->getOpcode() != AMDGPU::ENDIF)
 509           LastAlu.back() = nullptr;
 510         if (MI->getOpcode() == AMDGPU::CF_ALU)
 511           LastAlu.back() = MI;
 512         I++;
 513         bool RequiresWorkAround =
 514             CFStack.requiresWorkAroundForInst(MI->getOpcode());
 515         switch (MI->getOpcode()) {
 516         case AMDGPU::CF_ALU_PUSH_BEFORE:
 517           if (RequiresWorkAround) {
 518             DEBUG(dbgs() << "Applying bug work-around for ALU_PUSH_BEFORE\n");
 519             BuildMI(MBB, MI, MBB.findDebugLoc(MI), TII->get(AMDGPU::CF_PUSH_EG))
 520                 .addImm(CfCount + 1)
 521                 .addImm(1);
 522             MI->setDesc(TII->get(AMDGPU::CF_ALU));
 523             CfCount++;
 524             CFStack.pushBranch(AMDGPU::CF_PUSH_EG);
 525           } else
 526             CFStack.pushBranch(AMDGPU::CF_ALU_PUSH_BEFORE);
 527
 528         case AMDGPU::CF_ALU:
 529           I = MI;
 530           AluClauses.push_back(MakeALUClause(MBB, I));
 531           DEBUG(dbgs() << CfCount << ":"; MI->dump(););
 532           CfCount++;
 533           break;
 534         case AMDGPU::WHILELOOP: {
 535           CFStack.pushLoop();
 536           MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
 537               getHWInstrDesc(CF_WHILE_LOOP))
 538               .addImm(1);
 539           std::pair<unsigned, std::set<MachineInstr *> > Pair(CfCount,
 540               std::set<MachineInstr *>());
 541           Pair.second.insert(MIb);
 542           LoopStack.push_back(std::move(Pair));
 543           MI->eraseFromParent();
 544           CfCount++;
 545           break;
 546         }
 547         case AMDGPU::ENDLOOP: {
 548           CFStack.popLoop();
 549           std::pair<unsigned, std::set<MachineInstr *> > Pair =
 550               std::move(LoopStack.back());
 551           LoopStack.pop_back();
 552           CounterPropagateAddr(Pair.second, CfCount);
 553           BuildMI(MBB, MI, MBB.findDebugLoc(MI), getHWInstrDesc(CF_END_LOOP))
 554               .addImm(Pair.first + 1);
 555           MI->eraseFromParent();
 556           CfCount++;
 557           break;
 558         }
 559         case AMDGPU::IF_PREDICATE_SET: {
 560           LastAlu.push_back(nullptr);
 561           MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
 562               getHWInstrDesc(CF_JUMP))
 563               .addImm(0)
 564               .addImm(0);
 565           IfThenElseStack.push_back(MIb);
 566           DEBUG(dbgs() << CfCount << ":"; MIb->dump(););
 567           MI->eraseFromParent();
 568           CfCount++;
 569           break;
 570         }
 571         case AMDGPU::ELSE: {
 572           MachineInstr * JumpInst = IfThenElseStack.back();
 573           IfThenElseStack.pop_back();
 574           CounterPropagateAddr(JumpInst, CfCount);
 575           MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
 576               getHWInstrDesc(CF_ELSE))
 577               .addImm(0)
 578               .addImm(0);
 579           DEBUG(dbgs() << CfCount << ":"; MIb->dump(););
 580           IfThenElseStack.push_back(MIb);
 581           MI->eraseFromParent();
 582           CfCount++;
 583           break;
 584         }
 585         case AMDGPU::ENDIF: {
 586           CFStack.popBranch();
 587           if (LastAlu.back()) {
 588             ToPopAfter.push_back(LastAlu.back());
 589           } else {
 590             MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
 591                 getHWInstrDesc(CF_POP))
 592                 .addImm(CfCount + 1)
 593                 .addImm(1);
 594             (void)MIb;
 595             DEBUG(dbgs() << CfCount << ":"; MIb->dump(););
 596             CfCount++;
 597           }
 598
 599           MachineInstr *IfOrElseInst = IfThenElseStack.back();
 600           IfThenElseStack.pop_back();
 601           CounterPropagateAddr(IfOrElseInst, CfCount);
 602           IfOrElseInst->getOperand(1).setImm(1);
 603           LastAlu.pop_back();
 604           MI->eraseFromParent();
 605           break;
 606         }
 607         case AMDGPU::BREAK: {
 608           CfCount ++;
 609           MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
 610               getHWInstrDesc(CF_LOOP_BREAK))
 611               .addImm(0);
 612           LoopStack.back().second.insert(MIb);
 613           MI->eraseFromParent();
 614           break;
 615         }
 616         case AMDGPU::CONTINUE: {
 617           MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
 618               getHWInstrDesc(CF_LOOP_CONTINUE))
 619               .addImm(0);
 620           LoopStack.back().second.insert(MIb);
 621           MI->eraseFromParent();
 622           CfCount++;
 623           break;
 624         }
 625         case AMDGPU::RETURN: {
 626           BuildMI(MBB, MI, MBB.findDebugLoc(MI), getHWInstrDesc(CF_END));
 627           CfCount++;
 628           MI->eraseFromParent();
 629           if (CfCount % 2) {
 630             BuildMI(MBB, I, MBB.findDebugLoc(MI), TII->get(AMDGPU::PAD));
 631             CfCount++;
 632           }
 633           for (unsigned i = 0, e = FetchClauses.size(); i < e; i++)
 634             EmitFetchClause(I, FetchClauses[i], CfCount);
 635           for (unsigned i = 0, e = AluClauses.size(); i < e; i++)
 636             EmitALUClause(I, AluClauses[i], CfCount);
 637         }
 638         default:
 639           if (TII->isExport(MI->getOpcode())) {
 640             DEBUG(dbgs() << CfCount << ":"; MI->dump(););
 641             CfCount++;
 642           }
 643           break;
 644         }
 645       }
 646       for (unsigned i = 0, e = ToPopAfter.size(); i < e; ++i) {
 647         MachineInstr *Alu = ToPopAfter[i];
 648         BuildMI(MBB, Alu, MBB.findDebugLoc((MachineBasicBlock::iterator)Alu),
 649             TII->get(AMDGPU::CF_ALU_POP_AFTER))
 650             .addImm(Alu->getOperand(0).getImm())
 651             .addImm(Alu->getOperand(1).getImm())
 652             .addImm(Alu->getOperand(2).getImm())
 653             .addImm(Alu->getOperand(3).getImm())
 654             .addImm(Alu->getOperand(4).getImm())
 655             .addImm(Alu->getOperand(5).getImm())
 656             .addImm(Alu->getOperand(6).getImm())
 657             .addImm(Alu->getOperand(7).getImm())
 658             .addImm(Alu->getOperand(8).getImm());
 659         Alu->eraseFromParent();
 660       }
 661       MFI->StackSize = CFStack.MaxStackSize;
 662     }
 663
 664     return false;
 665   }
 666
 667   const char *getPassName() const override {
 668     return "R600 Control Flow Finalizer Pass";
 669   }
 670 };
 671
 672 char R600ControlFlowFinalizer::ID = 0;
 673
 674 } // end anonymous namespace
 675
 676
 677 llvm::FunctionPass *llvm::createR600ControlFlowFinalizer(TargetMachine &TM) {
 678   return new R600ControlFlowFinalizer(TM);
 679 }