SelectionDAGISel.cpp revision faeb4a35197737b3674fcfc34fd6e84220aa437b
1//===-- SelectionDAGISel.cpp - Implement the SelectionDAGISel class -------===// 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 implements the SelectionDAGISel class. 11// 12//===----------------------------------------------------------------------===// 13 14#define DEBUG_TYPE "isel" 15#include "llvm/CodeGen/SelectionDAGISel.h" 16#include "SelectionDAGBuild.h" 17#include "llvm/ADT/BitVector.h" 18#include "llvm/Analysis/AliasAnalysis.h" 19#include "llvm/Constants.h" 20#include "llvm/CallingConv.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/Function.h" 23#include "llvm/GlobalVariable.h" 24#include "llvm/InlineAsm.h" 25#include "llvm/Instructions.h" 26#include "llvm/Intrinsics.h" 27#include "llvm/IntrinsicInst.h" 28#include "llvm/ParameterAttributes.h" 29#include "llvm/CodeGen/FastISel.h" 30#include "llvm/CodeGen/GCStrategy.h" 31#include "llvm/CodeGen/GCMetadata.h" 32#include "llvm/CodeGen/MachineFunction.h" 33#include "llvm/CodeGen/MachineFrameInfo.h" 34#include "llvm/CodeGen/MachineInstrBuilder.h" 35#include "llvm/CodeGen/MachineJumpTableInfo.h" 36#include "llvm/CodeGen/MachineModuleInfo.h" 37#include "llvm/CodeGen/MachineRegisterInfo.h" 38#include "llvm/CodeGen/ScheduleDAG.h" 39#include "llvm/CodeGen/SchedulerRegistry.h" 40#include "llvm/CodeGen/SelectionDAG.h" 41#include "llvm/Target/TargetRegisterInfo.h" 42#include "llvm/Target/TargetData.h" 43#include "llvm/Target/TargetFrameInfo.h" 44#include "llvm/Target/TargetInstrInfo.h" 45#include "llvm/Target/TargetLowering.h" 46#include "llvm/Target/TargetMachine.h" 47#include "llvm/Target/TargetOptions.h" 48#include "llvm/Support/Compiler.h" 49#include "llvm/Support/Debug.h" 50#include "llvm/Support/MathExtras.h" 51#include "llvm/Support/Timer.h" 52#include <algorithm> 53using namespace llvm; 54 55static cl::opt<bool> 56EnableValueProp("enable-value-prop", cl::Hidden); 57static cl::opt<bool> 58EnableLegalizeTypes("enable-legalize-types", cl::Hidden); 59static cl::opt<bool> 60EnableFastISel("fast-isel", cl::Hidden, 61 cl::desc("Enable the experimental \"fast\" instruction selector")); 62static cl::opt<bool> 63EnableFastISelVerbose("fast-isel-verbose", cl::Hidden, 64 cl::desc("Enable verbose messages in the experimental \"fast\" " 65 "instruction selector")); 66static cl::opt<bool> 67EnableFastISelAbort("fast-isel-abort", cl::Hidden, 68 cl::desc("Enable abort calls when \"fast\" instruction fails")); 69static cl::opt<bool> 70SchedLiveInCopies("schedule-livein-copies", 71 cl::desc("Schedule copies of livein registers"), 72 cl::init(false)); 73 74#ifndef NDEBUG 75static cl::opt<bool> 76ViewDAGCombine1("view-dag-combine1-dags", cl::Hidden, 77 cl::desc("Pop up a window to show dags before the first " 78 "dag combine pass")); 79static cl::opt<bool> 80ViewLegalizeTypesDAGs("view-legalize-types-dags", cl::Hidden, 81 cl::desc("Pop up a window to show dags before legalize types")); 82static cl::opt<bool> 83ViewLegalizeDAGs("view-legalize-dags", cl::Hidden, 84 cl::desc("Pop up a window to show dags before legalize")); 85static cl::opt<bool> 86ViewDAGCombine2("view-dag-combine2-dags", cl::Hidden, 87 cl::desc("Pop up a window to show dags before the second " 88 "dag combine pass")); 89static cl::opt<bool> 90ViewISelDAGs("view-isel-dags", cl::Hidden, 91 cl::desc("Pop up a window to show isel dags as they are selected")); 92static cl::opt<bool> 93ViewSchedDAGs("view-sched-dags", cl::Hidden, 94 cl::desc("Pop up a window to show sched dags as they are processed")); 95static cl::opt<bool> 96ViewSUnitDAGs("view-sunit-dags", cl::Hidden, 97 cl::desc("Pop up a window to show SUnit dags after they are processed")); 98#else 99static const bool ViewDAGCombine1 = false, 100 ViewLegalizeTypesDAGs = false, ViewLegalizeDAGs = false, 101 ViewDAGCombine2 = false, 102 ViewISelDAGs = false, ViewSchedDAGs = false, 103 ViewSUnitDAGs = false; 104#endif 105 106//===---------------------------------------------------------------------===// 107/// 108/// RegisterScheduler class - Track the registration of instruction schedulers. 109/// 110//===---------------------------------------------------------------------===// 111MachinePassRegistry RegisterScheduler::Registry; 112 113//===---------------------------------------------------------------------===// 114/// 115/// ISHeuristic command line option for instruction schedulers. 116/// 117//===---------------------------------------------------------------------===// 118static cl::opt<RegisterScheduler::FunctionPassCtor, false, 119 RegisterPassParser<RegisterScheduler> > 120ISHeuristic("pre-RA-sched", 121 cl::init(&createDefaultScheduler), 122 cl::desc("Instruction schedulers available (before register" 123 " allocation):")); 124 125static RegisterScheduler 126defaultListDAGScheduler("default", " Best scheduler for the target", 127 createDefaultScheduler); 128 129namespace llvm { 130 //===--------------------------------------------------------------------===// 131 /// createDefaultScheduler - This creates an instruction scheduler appropriate 132 /// for the target. 133 ScheduleDAG* createDefaultScheduler(SelectionDAGISel *IS, 134 SelectionDAG *DAG, 135 MachineBasicBlock *BB, 136 bool Fast) { 137 TargetLowering &TLI = IS->getTargetLowering(); 138 139 if (TLI.getSchedulingPreference() == TargetLowering::SchedulingForLatency) { 140 return createTDListDAGScheduler(IS, DAG, BB, Fast); 141 } else { 142 assert(TLI.getSchedulingPreference() == 143 TargetLowering::SchedulingForRegPressure && "Unknown sched type!"); 144 return createBURRListDAGScheduler(IS, DAG, BB, Fast); 145 } 146 } 147} 148 149// EmitInstrWithCustomInserter - This method should be implemented by targets 150// that mark instructions with the 'usesCustomDAGSchedInserter' flag. These 151// instructions are special in various ways, which require special support to 152// insert. The specified MachineInstr is created but not inserted into any 153// basic blocks, and the scheduler passes ownership of it to this method. 154MachineBasicBlock *TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI, 155 MachineBasicBlock *MBB) { 156 cerr << "If a target marks an instruction with " 157 << "'usesCustomDAGSchedInserter', it must implement " 158 << "TargetLowering::EmitInstrWithCustomInserter!\n"; 159 abort(); 160 return 0; 161} 162 163/// EmitLiveInCopy - Emit a copy for a live in physical register. If the 164/// physical register has only a single copy use, then coalesced the copy 165/// if possible. 166static void EmitLiveInCopy(MachineBasicBlock *MBB, 167 MachineBasicBlock::iterator &InsertPos, 168 unsigned VirtReg, unsigned PhysReg, 169 const TargetRegisterClass *RC, 170 DenseMap<MachineInstr*, unsigned> &CopyRegMap, 171 const MachineRegisterInfo &MRI, 172 const TargetRegisterInfo &TRI, 173 const TargetInstrInfo &TII) { 174 unsigned NumUses = 0; 175 MachineInstr *UseMI = NULL; 176 for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg), 177 UE = MRI.use_end(); UI != UE; ++UI) { 178 UseMI = &*UI; 179 if (++NumUses > 1) 180 break; 181 } 182 183 // If the number of uses is not one, or the use is not a move instruction, 184 // don't coalesce. Also, only coalesce away a virtual register to virtual 185 // register copy. 186 bool Coalesced = false; 187 unsigned SrcReg, DstReg; 188 if (NumUses == 1 && 189 TII.isMoveInstr(*UseMI, SrcReg, DstReg) && 190 TargetRegisterInfo::isVirtualRegister(DstReg)) { 191 VirtReg = DstReg; 192 Coalesced = true; 193 } 194 195 // Now find an ideal location to insert the copy. 196 MachineBasicBlock::iterator Pos = InsertPos; 197 while (Pos != MBB->begin()) { 198 MachineInstr *PrevMI = prior(Pos); 199 DenseMap<MachineInstr*, unsigned>::iterator RI = CopyRegMap.find(PrevMI); 200 // copyRegToReg might emit multiple instructions to do a copy. 201 unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second; 202 if (CopyDstReg && !TRI.regsOverlap(CopyDstReg, PhysReg)) 203 // This is what the BB looks like right now: 204 // r1024 = mov r0 205 // ... 206 // r1 = mov r1024 207 // 208 // We want to insert "r1025 = mov r1". Inserting this copy below the 209 // move to r1024 makes it impossible for that move to be coalesced. 210 // 211 // r1025 = mov r1 212 // r1024 = mov r0 213 // ... 214 // r1 = mov 1024 215 // r2 = mov 1025 216 break; // Woot! Found a good location. 217 --Pos; 218 } 219 220 TII.copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC); 221 CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg)); 222 if (Coalesced) { 223 if (&*InsertPos == UseMI) ++InsertPos; 224 MBB->erase(UseMI); 225 } 226} 227 228/// EmitLiveInCopies - If this is the first basic block in the function, 229/// and if it has live ins that need to be copied into vregs, emit the 230/// copies into the block. 231static void EmitLiveInCopies(MachineBasicBlock *EntryMBB, 232 const MachineRegisterInfo &MRI, 233 const TargetRegisterInfo &TRI, 234 const TargetInstrInfo &TII) { 235 if (SchedLiveInCopies) { 236 // Emit the copies at a heuristically-determined location in the block. 237 DenseMap<MachineInstr*, unsigned> CopyRegMap; 238 MachineBasicBlock::iterator InsertPos = EntryMBB->begin(); 239 for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(), 240 E = MRI.livein_end(); LI != E; ++LI) 241 if (LI->second) { 242 const TargetRegisterClass *RC = MRI.getRegClass(LI->second); 243 EmitLiveInCopy(EntryMBB, InsertPos, LI->second, LI->first, 244 RC, CopyRegMap, MRI, TRI, TII); 245 } 246 } else { 247 // Emit the copies into the top of the block. 248 for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(), 249 E = MRI.livein_end(); LI != E; ++LI) 250 if (LI->second) { 251 const TargetRegisterClass *RC = MRI.getRegClass(LI->second); 252 TII.copyRegToReg(*EntryMBB, EntryMBB->begin(), 253 LI->second, LI->first, RC, RC); 254 } 255 } 256} 257 258//===----------------------------------------------------------------------===// 259// SelectionDAGISel code 260//===----------------------------------------------------------------------===// 261 262SelectionDAGISel::SelectionDAGISel(TargetLowering &tli, bool fast) : 263 FunctionPass(&ID), TLI(tli), 264 FuncInfo(new FunctionLoweringInfo(TLI)), 265 CurDAG(new SelectionDAG(TLI, *FuncInfo)), 266 SDL(new SelectionDAGLowering(*CurDAG, TLI, *FuncInfo)), 267 GFI(), 268 Fast(fast), 269 DAGSize(0) 270{} 271 272SelectionDAGISel::~SelectionDAGISel() { 273 delete SDL; 274 delete CurDAG; 275 delete FuncInfo; 276} 277 278unsigned SelectionDAGISel::MakeReg(MVT VT) { 279 return RegInfo->createVirtualRegister(TLI.getRegClassFor(VT)); 280} 281 282void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const { 283 AU.addRequired<AliasAnalysis>(); 284 AU.addRequired<GCModuleInfo>(); 285 AU.setPreservesAll(); 286} 287 288bool SelectionDAGISel::runOnFunction(Function &Fn) { 289 // Do some sanity-checking on the command-line options. 290 assert((!EnableFastISelVerbose || EnableFastISel) && 291 "-fast-isel-verbose requires -fast-isel"); 292 assert((!EnableFastISelAbort || EnableFastISel) && 293 "-fast-isel-abort requires -fast-isel"); 294 295 // Get alias analysis for load/store combining. 296 AA = &getAnalysis<AliasAnalysis>(); 297 298 TargetMachine &TM = TLI.getTargetMachine(); 299 MachineFunction &MF = MachineFunction::construct(&Fn, TM); 300 const MachineRegisterInfo &MRI = MF.getRegInfo(); 301 const TargetInstrInfo &TII = *TM.getInstrInfo(); 302 const TargetRegisterInfo &TRI = *TM.getRegisterInfo(); 303 304 if (MF.getFunction()->hasGC()) 305 GFI = &getAnalysis<GCModuleInfo>().getFunctionInfo(*MF.getFunction()); 306 else 307 GFI = 0; 308 RegInfo = &MF.getRegInfo(); 309 DOUT << "\n\n\n=== " << Fn.getName() << "\n"; 310 311 FuncInfo->set(Fn, MF, EnableFastISel); 312 CurDAG->init(MF, getAnalysisToUpdate<MachineModuleInfo>()); 313 SDL->init(GFI, *AA); 314 315 for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) 316 if (InvokeInst *Invoke = dyn_cast<InvokeInst>(I->getTerminator())) 317 // Mark landing pad. 318 FuncInfo->MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad(); 319 320 SelectAllBasicBlocks(Fn, MF); 321 322 // If the first basic block in the function has live ins that need to be 323 // copied into vregs, emit the copies into the top of the block before 324 // emitting the code for the block. 325 EmitLiveInCopies(MF.begin(), MRI, TRI, TII); 326 327 // Add function live-ins to entry block live-in set. 328 for (MachineRegisterInfo::livein_iterator I = RegInfo->livein_begin(), 329 E = RegInfo->livein_end(); I != E; ++I) 330 MF.begin()->addLiveIn(I->first); 331 332#ifndef NDEBUG 333 assert(FuncInfo->CatchInfoFound.size() == FuncInfo->CatchInfoLost.size() && 334 "Not all catch info was assigned to a landing pad!"); 335#endif 336 337 FuncInfo->clear(); 338 339 return true; 340} 341 342static void copyCatchInfo(BasicBlock *SrcBB, BasicBlock *DestBB, 343 MachineModuleInfo *MMI, FunctionLoweringInfo &FLI) { 344 for (BasicBlock::iterator I = SrcBB->begin(), E = --SrcBB->end(); I != E; ++I) 345 if (EHSelectorInst *EHSel = dyn_cast<EHSelectorInst>(I)) { 346 // Apply the catch info to DestBB. 347 AddCatchInfo(*EHSel, MMI, FLI.MBBMap[DestBB]); 348#ifndef NDEBUG 349 if (!FLI.MBBMap[SrcBB]->isLandingPad()) 350 FLI.CatchInfoFound.insert(EHSel); 351#endif 352 } 353} 354 355/// IsFixedFrameObjectWithPosOffset - Check if object is a fixed frame object and 356/// whether object offset >= 0. 357static bool 358IsFixedFrameObjectWithPosOffset(MachineFrameInfo * MFI, SDValue Op) { 359 if (!isa<FrameIndexSDNode>(Op)) return false; 360 361 FrameIndexSDNode * FrameIdxNode = dyn_cast<FrameIndexSDNode>(Op); 362 int FrameIdx = FrameIdxNode->getIndex(); 363 return MFI->isFixedObjectIndex(FrameIdx) && 364 MFI->getObjectOffset(FrameIdx) >= 0; 365} 366 367/// IsPossiblyOverwrittenArgumentOfTailCall - Check if the operand could 368/// possibly be overwritten when lowering the outgoing arguments in a tail 369/// call. Currently the implementation of this call is very conservative and 370/// assumes all arguments sourcing from FORMAL_ARGUMENTS or a CopyFromReg with 371/// virtual registers would be overwritten by direct lowering. 372static bool IsPossiblyOverwrittenArgumentOfTailCall(SDValue Op, 373 MachineFrameInfo * MFI) { 374 RegisterSDNode * OpReg = NULL; 375 if (Op.getOpcode() == ISD::FORMAL_ARGUMENTS || 376 (Op.getOpcode()== ISD::CopyFromReg && 377 (OpReg = dyn_cast<RegisterSDNode>(Op.getOperand(1))) && 378 (OpReg->getReg() >= TargetRegisterInfo::FirstVirtualRegister)) || 379 (Op.getOpcode() == ISD::LOAD && 380 IsFixedFrameObjectWithPosOffset(MFI, Op.getOperand(1))) || 381 (Op.getOpcode() == ISD::MERGE_VALUES && 382 Op.getOperand(Op.getResNo()).getOpcode() == ISD::LOAD && 383 IsFixedFrameObjectWithPosOffset(MFI, Op.getOperand(Op.getResNo()). 384 getOperand(1)))) 385 return true; 386 return false; 387} 388 389/// CheckDAGForTailCallsAndFixThem - This Function looks for CALL nodes in the 390/// DAG and fixes their tailcall attribute operand. 391static void CheckDAGForTailCallsAndFixThem(SelectionDAG &DAG, 392 TargetLowering& TLI) { 393 SDNode * Ret = NULL; 394 SDValue Terminator = DAG.getRoot(); 395 396 // Find RET node. 397 if (Terminator.getOpcode() == ISD::RET) { 398 Ret = Terminator.getNode(); 399 } 400 401 // Fix tail call attribute of CALL nodes. 402 for (SelectionDAG::allnodes_iterator BE = DAG.allnodes_begin(), 403 BI = DAG.allnodes_end(); BI != BE; ) { 404 --BI; 405 if (BI->getOpcode() == ISD::CALL) { 406 SDValue OpRet(Ret, 0); 407 SDValue OpCall(BI, 0); 408 bool isMarkedTailCall = 409 cast<ConstantSDNode>(OpCall.getOperand(3))->getZExtValue() != 0; 410 // If CALL node has tail call attribute set to true and the call is not 411 // eligible (no RET or the target rejects) the attribute is fixed to 412 // false. The TargetLowering::IsEligibleForTailCallOptimization function 413 // must correctly identify tail call optimizable calls. 414 if (!isMarkedTailCall) continue; 415 if (Ret==NULL || 416 !TLI.IsEligibleForTailCallOptimization(OpCall, OpRet, DAG)) { 417 // Not eligible. Mark CALL node as non tail call. 418 SmallVector<SDValue, 32> Ops; 419 unsigned idx=0; 420 for(SDNode::op_iterator I =OpCall.getNode()->op_begin(), 421 E = OpCall.getNode()->op_end(); I != E; I++, idx++) { 422 if (idx!=3) 423 Ops.push_back(*I); 424 else 425 Ops.push_back(DAG.getConstant(false, TLI.getPointerTy())); 426 } 427 DAG.UpdateNodeOperands(OpCall, Ops.begin(), Ops.size()); 428 } else { 429 // Look for tail call clobbered arguments. Emit a series of 430 // copyto/copyfrom virtual register nodes to protect them. 431 SmallVector<SDValue, 32> Ops; 432 SDValue Chain = OpCall.getOperand(0), InFlag; 433 unsigned idx=0; 434 for(SDNode::op_iterator I = OpCall.getNode()->op_begin(), 435 E = OpCall.getNode()->op_end(); I != E; I++, idx++) { 436 SDValue Arg = *I; 437 if (idx > 4 && (idx % 2)) { 438 bool isByVal = cast<ARG_FLAGSSDNode>(OpCall.getOperand(idx+1))-> 439 getArgFlags().isByVal(); 440 MachineFunction &MF = DAG.getMachineFunction(); 441 MachineFrameInfo *MFI = MF.getFrameInfo(); 442 if (!isByVal && 443 IsPossiblyOverwrittenArgumentOfTailCall(Arg, MFI)) { 444 MVT VT = Arg.getValueType(); 445 unsigned VReg = MF.getRegInfo(). 446 createVirtualRegister(TLI.getRegClassFor(VT)); 447 Chain = DAG.getCopyToReg(Chain, VReg, Arg, InFlag); 448 InFlag = Chain.getValue(1); 449 Arg = DAG.getCopyFromReg(Chain, VReg, VT, InFlag); 450 Chain = Arg.getValue(1); 451 InFlag = Arg.getValue(2); 452 } 453 } 454 Ops.push_back(Arg); 455 } 456 // Link in chain of CopyTo/CopyFromReg. 457 Ops[0] = Chain; 458 DAG.UpdateNodeOperands(OpCall, Ops.begin(), Ops.size()); 459 } 460 } 461 } 462} 463 464void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB, 465 BasicBlock::iterator Begin, 466 BasicBlock::iterator End) { 467 SDL->setCurrentBasicBlock(BB); 468 469 MachineModuleInfo *MMI = CurDAG->getMachineModuleInfo(); 470 471 if (MMI && BB->isLandingPad()) { 472 // Add a label to mark the beginning of the landing pad. Deletion of the 473 // landing pad can thus be detected via the MachineModuleInfo. 474 unsigned LabelID = MMI->addLandingPad(BB); 475 CurDAG->setRoot(CurDAG->getLabel(ISD::EH_LABEL, 476 CurDAG->getEntryNode(), LabelID)); 477 478 // Mark exception register as live in. 479 unsigned Reg = TLI.getExceptionAddressRegister(); 480 if (Reg) BB->addLiveIn(Reg); 481 482 // Mark exception selector register as live in. 483 Reg = TLI.getExceptionSelectorRegister(); 484 if (Reg) BB->addLiveIn(Reg); 485 486 // FIXME: Hack around an exception handling flaw (PR1508): the personality 487 // function and list of typeids logically belong to the invoke (or, if you 488 // like, the basic block containing the invoke), and need to be associated 489 // with it in the dwarf exception handling tables. Currently however the 490 // information is provided by an intrinsic (eh.selector) that can be moved 491 // to unexpected places by the optimizers: if the unwind edge is critical, 492 // then breaking it can result in the intrinsics being in the successor of 493 // the landing pad, not the landing pad itself. This results in exceptions 494 // not being caught because no typeids are associated with the invoke. 495 // This may not be the only way things can go wrong, but it is the only way 496 // we try to work around for the moment. 497 BranchInst *Br = dyn_cast<BranchInst>(LLVMBB->getTerminator()); 498 499 if (Br && Br->isUnconditional()) { // Critical edge? 500 BasicBlock::iterator I, E; 501 for (I = LLVMBB->begin(), E = --LLVMBB->end(); I != E; ++I) 502 if (isa<EHSelectorInst>(I)) 503 break; 504 505 if (I == E) 506 // No catch info found - try to extract some from the successor. 507 copyCatchInfo(Br->getSuccessor(0), LLVMBB, MMI, *FuncInfo); 508 } 509 } 510 511 // Lower all of the non-terminator instructions. 512 for (BasicBlock::iterator I = Begin; I != End; ++I) 513 if (!isa<TerminatorInst>(I)) 514 SDL->visit(*I); 515 516 // Ensure that all instructions which are used outside of their defining 517 // blocks are available as virtual registers. Invoke is handled elsewhere. 518 for (BasicBlock::iterator I = Begin; I != End; ++I) 519 if (!I->use_empty() && !isa<PHINode>(I) && !isa<InvokeInst>(I)) { 520 DenseMap<const Value*,unsigned>::iterator VMI =FuncInfo->ValueMap.find(I); 521 if (VMI != FuncInfo->ValueMap.end()) 522 SDL->CopyValueToVirtualRegister(I, VMI->second); 523 } 524 525 // Handle PHI nodes in successor blocks. 526 if (End == LLVMBB->end()) { 527 HandlePHINodesInSuccessorBlocks(LLVMBB); 528 529 // Lower the terminator after the copies are emitted. 530 SDL->visit(*LLVMBB->getTerminator()); 531 } 532 533 // Make sure the root of the DAG is up-to-date. 534 CurDAG->setRoot(SDL->getControlRoot()); 535 536 // Check whether calls in this block are real tail calls. Fix up CALL nodes 537 // with correct tailcall attribute so that the target can rely on the tailcall 538 // attribute indicating whether the call is really eligible for tail call 539 // optimization. 540 CheckDAGForTailCallsAndFixThem(*CurDAG, TLI); 541 542 // Final step, emit the lowered DAG as machine code. 543 CodeGenAndEmitDAG(); 544 SDL->clear(); 545} 546 547void SelectionDAGISel::ComputeLiveOutVRegInfo() { 548 SmallPtrSet<SDNode*, 128> VisitedNodes; 549 SmallVector<SDNode*, 128> Worklist; 550 551 Worklist.push_back(CurDAG->getRoot().getNode()); 552 553 APInt Mask; 554 APInt KnownZero; 555 APInt KnownOne; 556 557 while (!Worklist.empty()) { 558 SDNode *N = Worklist.back(); 559 Worklist.pop_back(); 560 561 // If we've already seen this node, ignore it. 562 if (!VisitedNodes.insert(N)) 563 continue; 564 565 // Otherwise, add all chain operands to the worklist. 566 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 567 if (N->getOperand(i).getValueType() == MVT::Other) 568 Worklist.push_back(N->getOperand(i).getNode()); 569 570 // If this is a CopyToReg with a vreg dest, process it. 571 if (N->getOpcode() != ISD::CopyToReg) 572 continue; 573 574 unsigned DestReg = cast<RegisterSDNode>(N->getOperand(1))->getReg(); 575 if (!TargetRegisterInfo::isVirtualRegister(DestReg)) 576 continue; 577 578 // Ignore non-scalar or non-integer values. 579 SDValue Src = N->getOperand(2); 580 MVT SrcVT = Src.getValueType(); 581 if (!SrcVT.isInteger() || SrcVT.isVector()) 582 continue; 583 584 unsigned NumSignBits = CurDAG->ComputeNumSignBits(Src); 585 Mask = APInt::getAllOnesValue(SrcVT.getSizeInBits()); 586 CurDAG->ComputeMaskedBits(Src, Mask, KnownZero, KnownOne); 587 588 // Only install this information if it tells us something. 589 if (NumSignBits != 1 || KnownZero != 0 || KnownOne != 0) { 590 DestReg -= TargetRegisterInfo::FirstVirtualRegister; 591 FunctionLoweringInfo &FLI = CurDAG->getFunctionLoweringInfo(); 592 if (DestReg >= FLI.LiveOutRegInfo.size()) 593 FLI.LiveOutRegInfo.resize(DestReg+1); 594 FunctionLoweringInfo::LiveOutInfo &LOI = FLI.LiveOutRegInfo[DestReg]; 595 LOI.NumSignBits = NumSignBits; 596 LOI.KnownOne = NumSignBits; 597 LOI.KnownZero = NumSignBits; 598 } 599 } 600} 601 602void SelectionDAGISel::CodeGenAndEmitDAG() { 603 std::string GroupName; 604 if (TimePassesIsEnabled) 605 GroupName = "Instruction Selection and Scheduling"; 606 std::string BlockName; 607 if (ViewDAGCombine1 || ViewLegalizeTypesDAGs || ViewLegalizeDAGs || 608 ViewDAGCombine2 || ViewISelDAGs || ViewSchedDAGs || ViewSUnitDAGs) 609 BlockName = CurDAG->getMachineFunction().getFunction()->getName() + ':' + 610 BB->getBasicBlock()->getName(); 611 612 DOUT << "Initial selection DAG:\n"; 613 DEBUG(CurDAG->dump()); 614 615 if (ViewDAGCombine1) CurDAG->viewGraph("dag-combine1 input for " + BlockName); 616 617 // Run the DAG combiner in pre-legalize mode. 618 if (TimePassesIsEnabled) { 619 NamedRegionTimer T("DAG Combining 1", GroupName); 620 CurDAG->Combine(false, *AA, Fast); 621 } else { 622 CurDAG->Combine(false, *AA, Fast); 623 } 624 625 DOUT << "Optimized lowered selection DAG:\n"; 626 DEBUG(CurDAG->dump()); 627 628 // Second step, hack on the DAG until it only uses operations and types that 629 // the target supports. 630 if (EnableLegalizeTypes) {// Enable this some day. 631 if (ViewLegalizeTypesDAGs) CurDAG->viewGraph("legalize-types input for " + 632 BlockName); 633 634 if (TimePassesIsEnabled) { 635 NamedRegionTimer T("Type Legalization", GroupName); 636 CurDAG->LegalizeTypes(); 637 } else { 638 CurDAG->LegalizeTypes(); 639 } 640 641 DOUT << "Type-legalized selection DAG:\n"; 642 DEBUG(CurDAG->dump()); 643 644 // TODO: enable a dag combine pass here. 645 } 646 647 if (ViewLegalizeDAGs) CurDAG->viewGraph("legalize input for " + BlockName); 648 649 if (TimePassesIsEnabled) { 650 NamedRegionTimer T("DAG Legalization", GroupName); 651 CurDAG->Legalize(); 652 } else { 653 CurDAG->Legalize(); 654 } 655 656 DOUT << "Legalized selection DAG:\n"; 657 DEBUG(CurDAG->dump()); 658 659 if (ViewDAGCombine2) CurDAG->viewGraph("dag-combine2 input for " + BlockName); 660 661 // Run the DAG combiner in post-legalize mode. 662 if (TimePassesIsEnabled) { 663 NamedRegionTimer T("DAG Combining 2", GroupName); 664 CurDAG->Combine(true, *AA, Fast); 665 } else { 666 CurDAG->Combine(true, *AA, Fast); 667 } 668 669 DOUT << "Optimized legalized selection DAG:\n"; 670 DEBUG(CurDAG->dump()); 671 672 if (ViewISelDAGs) CurDAG->viewGraph("isel input for " + BlockName); 673 674 if (!Fast && EnableValueProp) 675 ComputeLiveOutVRegInfo(); 676 677 // Third, instruction select all of the operations to machine code, adding the 678 // code to the MachineBasicBlock. 679 if (TimePassesIsEnabled) { 680 NamedRegionTimer T("Instruction Selection", GroupName); 681 InstructionSelect(); 682 } else { 683 InstructionSelect(); 684 } 685 686 DOUT << "Selected selection DAG:\n"; 687 DEBUG(CurDAG->dump()); 688 689 if (ViewSchedDAGs) CurDAG->viewGraph("scheduler input for " + BlockName); 690 691 // Schedule machine code. 692 ScheduleDAG *Scheduler; 693 if (TimePassesIsEnabled) { 694 NamedRegionTimer T("Instruction Scheduling", GroupName); 695 Scheduler = Schedule(); 696 } else { 697 Scheduler = Schedule(); 698 } 699 700 if (ViewSUnitDAGs) Scheduler->viewGraph(); 701 702 // Emit machine code to BB. This can change 'BB' to the last block being 703 // inserted into. 704 if (TimePassesIsEnabled) { 705 NamedRegionTimer T("Instruction Creation", GroupName); 706 BB = Scheduler->EmitSchedule(); 707 } else { 708 BB = Scheduler->EmitSchedule(); 709 } 710 711 // Free the scheduler state. 712 if (TimePassesIsEnabled) { 713 NamedRegionTimer T("Instruction Scheduling Cleanup", GroupName); 714 delete Scheduler; 715 } else { 716 delete Scheduler; 717 } 718 719 DOUT << "Selected machine code:\n"; 720 DEBUG(BB->dump()); 721} 722 723void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn, MachineFunction &MF) { 724 for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) { 725 BasicBlock *LLVMBB = &*I; 726 BB = FuncInfo->MBBMap[LLVMBB]; 727 728 BasicBlock::iterator const Begin = LLVMBB->begin(); 729 BasicBlock::iterator const End = LLVMBB->end(); 730 BasicBlock::iterator BI = Begin; 731 732 // Lower any arguments needed in this block if this is the entry block. 733 if (LLVMBB == &Fn.getEntryBlock()) 734 LowerArguments(LLVMBB); 735 736 // Before doing SelectionDAG ISel, see if FastISel has been requested. 737 // FastISel doesn't support EH landing pads, which require special handling. 738 if (EnableFastISel && !BB->isLandingPad()) { 739 if (FastISel *F = TLI.createFastISel(*FuncInfo->MF, FuncInfo->ValueMap, 740 FuncInfo->MBBMap, 741 FuncInfo->StaticAllocaMap)) { 742 // Emit code for any incoming arguments. This must happen before 743 // beginning FastISel on the entry block. 744 if (LLVMBB == &Fn.getEntryBlock()) { 745 CurDAG->setRoot(SDL->getControlRoot()); 746 CodeGenAndEmitDAG(); 747 SDL->clear(); 748 } 749 F->setCurrentBlock(BB); 750 // Do FastISel on as many instructions as possible. 751 for (; BI != End; ++BI) { 752 // Just before the terminator instruction, insert instructions to 753 // feed PHI nodes in successor blocks. 754 if (isa<TerminatorInst>(BI)) 755 if (!HandlePHINodesInSuccessorBlocksFast(LLVMBB, F)) { 756 if (EnableFastISelVerbose || EnableFastISelAbort) { 757 cerr << "FastISel miss: "; 758 BI->dump(); 759 } 760 if (EnableFastISelAbort) 761 assert(0 && "FastISel didn't handle a PHI in a successor"); 762 break; 763 } 764 765 // First try normal tablegen-generated "fast" selection. 766 if (F->SelectInstruction(BI)) 767 continue; 768 769 // Next, try calling the target to attempt to handle the instruction. 770 if (F->TargetSelectInstruction(BI)) 771 continue; 772 773 // Then handle certain instructions as single-LLVM-Instruction blocks. 774 if (isa<CallInst>(BI)) { 775 if (BI->getType() != Type::VoidTy) { 776 unsigned &R = FuncInfo->ValueMap[BI]; 777 if (!R) 778 R = FuncInfo->CreateRegForValue(BI); 779 } 780 781 SelectBasicBlock(LLVMBB, BI, next(BI)); 782 continue; 783 } 784 785 // Otherwise, give up on FastISel for the rest of the block. 786 // For now, be a little lenient about non-branch terminators. 787 if (!isa<TerminatorInst>(BI) || isa<BranchInst>(BI)) { 788 if (EnableFastISelVerbose || EnableFastISelAbort) { 789 cerr << "FastISel miss: "; 790 BI->dump(); 791 } 792 if (EnableFastISelAbort) 793 // The "fast" selector couldn't handle something and bailed. 794 // For the purpose of debugging, just abort. 795 assert(0 && "FastISel didn't select the entire block"); 796 } 797 break; 798 } 799 delete F; 800 } 801 } 802 803 // Run SelectionDAG instruction selection on the remainder of the block 804 // not handled by FastISel. If FastISel is not run, this is the entire 805 // block. 806 if (BI != End) 807 SelectBasicBlock(LLVMBB, BI, End); 808 809 FinishBasicBlock(); 810 } 811} 812 813void 814SelectionDAGISel::FinishBasicBlock() { 815 816 // Perform target specific isel post processing. 817 InstructionSelectPostProcessing(); 818 819 DOUT << "Target-post-processed machine code:\n"; 820 DEBUG(BB->dump()); 821 822 DOUT << "Total amount of phi nodes to update: " 823 << SDL->PHINodesToUpdate.size() << "\n"; 824 DEBUG(for (unsigned i = 0, e = SDL->PHINodesToUpdate.size(); i != e; ++i) 825 DOUT << "Node " << i << " : (" << SDL->PHINodesToUpdate[i].first 826 << ", " << SDL->PHINodesToUpdate[i].second << ")\n";); 827 828 // Next, now that we know what the last MBB the LLVM BB expanded is, update 829 // PHI nodes in successors. 830 if (SDL->SwitchCases.empty() && 831 SDL->JTCases.empty() && 832 SDL->BitTestCases.empty()) { 833 for (unsigned i = 0, e = SDL->PHINodesToUpdate.size(); i != e; ++i) { 834 MachineInstr *PHI = SDL->PHINodesToUpdate[i].first; 835 assert(PHI->getOpcode() == TargetInstrInfo::PHI && 836 "This is not a machine PHI node that we are updating!"); 837 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[i].second, 838 false)); 839 PHI->addOperand(MachineOperand::CreateMBB(BB)); 840 } 841 SDL->PHINodesToUpdate.clear(); 842 return; 843 } 844 845 for (unsigned i = 0, e = SDL->BitTestCases.size(); i != e; ++i) { 846 // Lower header first, if it wasn't already lowered 847 if (!SDL->BitTestCases[i].Emitted) { 848 // Set the current basic block to the mbb we wish to insert the code into 849 BB = SDL->BitTestCases[i].Parent; 850 SDL->setCurrentBasicBlock(BB); 851 // Emit the code 852 SDL->visitBitTestHeader(SDL->BitTestCases[i]); 853 CurDAG->setRoot(SDL->getRoot()); 854 CodeGenAndEmitDAG(); 855 SDL->clear(); 856 } 857 858 for (unsigned j = 0, ej = SDL->BitTestCases[i].Cases.size(); j != ej; ++j) { 859 // Set the current basic block to the mbb we wish to insert the code into 860 BB = SDL->BitTestCases[i].Cases[j].ThisBB; 861 SDL->setCurrentBasicBlock(BB); 862 // Emit the code 863 if (j+1 != ej) 864 SDL->visitBitTestCase(SDL->BitTestCases[i].Cases[j+1].ThisBB, 865 SDL->BitTestCases[i].Reg, 866 SDL->BitTestCases[i].Cases[j]); 867 else 868 SDL->visitBitTestCase(SDL->BitTestCases[i].Default, 869 SDL->BitTestCases[i].Reg, 870 SDL->BitTestCases[i].Cases[j]); 871 872 873 CurDAG->setRoot(SDL->getRoot()); 874 CodeGenAndEmitDAG(); 875 SDL->clear(); 876 } 877 878 // Update PHI Nodes 879 for (unsigned pi = 0, pe = SDL->PHINodesToUpdate.size(); pi != pe; ++pi) { 880 MachineInstr *PHI = SDL->PHINodesToUpdate[pi].first; 881 MachineBasicBlock *PHIBB = PHI->getParent(); 882 assert(PHI->getOpcode() == TargetInstrInfo::PHI && 883 "This is not a machine PHI node that we are updating!"); 884 // This is "default" BB. We have two jumps to it. From "header" BB and 885 // from last "case" BB. 886 if (PHIBB == SDL->BitTestCases[i].Default) { 887 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, 888 false)); 889 PHI->addOperand(MachineOperand::CreateMBB(SDL->BitTestCases[i].Parent)); 890 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, 891 false)); 892 PHI->addOperand(MachineOperand::CreateMBB(SDL->BitTestCases[i].Cases. 893 back().ThisBB)); 894 } 895 // One of "cases" BB. 896 for (unsigned j = 0, ej = SDL->BitTestCases[i].Cases.size(); 897 j != ej; ++j) { 898 MachineBasicBlock* cBB = SDL->BitTestCases[i].Cases[j].ThisBB; 899 if (cBB->succ_end() != 900 std::find(cBB->succ_begin(),cBB->succ_end(), PHIBB)) { 901 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, 902 false)); 903 PHI->addOperand(MachineOperand::CreateMBB(cBB)); 904 } 905 } 906 } 907 } 908 SDL->BitTestCases.clear(); 909 910 // If the JumpTable record is filled in, then we need to emit a jump table. 911 // Updating the PHI nodes is tricky in this case, since we need to determine 912 // whether the PHI is a successor of the range check MBB or the jump table MBB 913 for (unsigned i = 0, e = SDL->JTCases.size(); i != e; ++i) { 914 // Lower header first, if it wasn't already lowered 915 if (!SDL->JTCases[i].first.Emitted) { 916 // Set the current basic block to the mbb we wish to insert the code into 917 BB = SDL->JTCases[i].first.HeaderBB; 918 SDL->setCurrentBasicBlock(BB); 919 // Emit the code 920 SDL->visitJumpTableHeader(SDL->JTCases[i].second, SDL->JTCases[i].first); 921 CurDAG->setRoot(SDL->getRoot()); 922 CodeGenAndEmitDAG(); 923 SDL->clear(); 924 } 925 926 // Set the current basic block to the mbb we wish to insert the code into 927 BB = SDL->JTCases[i].second.MBB; 928 SDL->setCurrentBasicBlock(BB); 929 // Emit the code 930 SDL->visitJumpTable(SDL->JTCases[i].second); 931 CurDAG->setRoot(SDL->getRoot()); 932 CodeGenAndEmitDAG(); 933 SDL->clear(); 934 935 // Update PHI Nodes 936 for (unsigned pi = 0, pe = SDL->PHINodesToUpdate.size(); pi != pe; ++pi) { 937 MachineInstr *PHI = SDL->PHINodesToUpdate[pi].first; 938 MachineBasicBlock *PHIBB = PHI->getParent(); 939 assert(PHI->getOpcode() == TargetInstrInfo::PHI && 940 "This is not a machine PHI node that we are updating!"); 941 // "default" BB. We can go there only from header BB. 942 if (PHIBB == SDL->JTCases[i].second.Default) { 943 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, 944 false)); 945 PHI->addOperand(MachineOperand::CreateMBB(SDL->JTCases[i].first.HeaderBB)); 946 } 947 // JT BB. Just iterate over successors here 948 if (BB->succ_end() != std::find(BB->succ_begin(),BB->succ_end(), PHIBB)) { 949 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, 950 false)); 951 PHI->addOperand(MachineOperand::CreateMBB(BB)); 952 } 953 } 954 } 955 SDL->JTCases.clear(); 956 957 // If the switch block involved a branch to one of the actual successors, we 958 // need to update PHI nodes in that block. 959 for (unsigned i = 0, e = SDL->PHINodesToUpdate.size(); i != e; ++i) { 960 MachineInstr *PHI = SDL->PHINodesToUpdate[i].first; 961 assert(PHI->getOpcode() == TargetInstrInfo::PHI && 962 "This is not a machine PHI node that we are updating!"); 963 if (BB->isSuccessor(PHI->getParent())) { 964 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[i].second, 965 false)); 966 PHI->addOperand(MachineOperand::CreateMBB(BB)); 967 } 968 } 969 970 // If we generated any switch lowering information, build and codegen any 971 // additional DAGs necessary. 972 for (unsigned i = 0, e = SDL->SwitchCases.size(); i != e; ++i) { 973 // Set the current basic block to the mbb we wish to insert the code into 974 BB = SDL->SwitchCases[i].ThisBB; 975 SDL->setCurrentBasicBlock(BB); 976 977 // Emit the code 978 SDL->visitSwitchCase(SDL->SwitchCases[i]); 979 CurDAG->setRoot(SDL->getRoot()); 980 CodeGenAndEmitDAG(); 981 SDL->clear(); 982 983 // Handle any PHI nodes in successors of this chunk, as if we were coming 984 // from the original BB before switch expansion. Note that PHI nodes can 985 // occur multiple times in PHINodesToUpdate. We have to be very careful to 986 // handle them the right number of times. 987 while ((BB = SDL->SwitchCases[i].TrueBB)) { // Handle LHS and RHS. 988 for (MachineBasicBlock::iterator Phi = BB->begin(); 989 Phi != BB->end() && Phi->getOpcode() == TargetInstrInfo::PHI; ++Phi){ 990 // This value for this PHI node is recorded in PHINodesToUpdate, get it. 991 for (unsigned pn = 0; ; ++pn) { 992 assert(pn != SDL->PHINodesToUpdate.size() && 993 "Didn't find PHI entry!"); 994 if (SDL->PHINodesToUpdate[pn].first == Phi) { 995 Phi->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pn]. 996 second, false)); 997 Phi->addOperand(MachineOperand::CreateMBB(SDL->SwitchCases[i].ThisBB)); 998 break; 999 } 1000 } 1001 } 1002 1003 // Don't process RHS if same block as LHS. 1004 if (BB == SDL->SwitchCases[i].FalseBB) 1005 SDL->SwitchCases[i].FalseBB = 0; 1006 1007 // If we haven't handled the RHS, do so now. Otherwise, we're done. 1008 SDL->SwitchCases[i].TrueBB = SDL->SwitchCases[i].FalseBB; 1009 SDL->SwitchCases[i].FalseBB = 0; 1010 } 1011 assert(SDL->SwitchCases[i].TrueBB == 0 && SDL->SwitchCases[i].FalseBB == 0); 1012 } 1013 SDL->SwitchCases.clear(); 1014 1015 SDL->PHINodesToUpdate.clear(); 1016} 1017 1018 1019/// Schedule - Pick a safe ordering for instructions for each 1020/// target node in the graph. 1021/// 1022ScheduleDAG *SelectionDAGISel::Schedule() { 1023 RegisterScheduler::FunctionPassCtor Ctor = RegisterScheduler::getDefault(); 1024 1025 if (!Ctor) { 1026 Ctor = ISHeuristic; 1027 RegisterScheduler::setDefault(Ctor); 1028 } 1029 1030 ScheduleDAG *Scheduler = Ctor(this, CurDAG, BB, Fast); 1031 Scheduler->Run(); 1032 1033 return Scheduler; 1034} 1035 1036 1037HazardRecognizer *SelectionDAGISel::CreateTargetHazardRecognizer() { 1038 return new HazardRecognizer(); 1039} 1040 1041//===----------------------------------------------------------------------===// 1042// Helper functions used by the generated instruction selector. 1043//===----------------------------------------------------------------------===// 1044// Calls to these methods are generated by tblgen. 1045 1046/// CheckAndMask - The isel is trying to match something like (and X, 255). If 1047/// the dag combiner simplified the 255, we still want to match. RHS is the 1048/// actual value in the DAG on the RHS of an AND, and DesiredMaskS is the value 1049/// specified in the .td file (e.g. 255). 1050bool SelectionDAGISel::CheckAndMask(SDValue LHS, ConstantSDNode *RHS, 1051 int64_t DesiredMaskS) const { 1052 const APInt &ActualMask = RHS->getAPIntValue(); 1053 const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS); 1054 1055 // If the actual mask exactly matches, success! 1056 if (ActualMask == DesiredMask) 1057 return true; 1058 1059 // If the actual AND mask is allowing unallowed bits, this doesn't match. 1060 if (ActualMask.intersects(~DesiredMask)) 1061 return false; 1062 1063 // Otherwise, the DAG Combiner may have proven that the value coming in is 1064 // either already zero or is not demanded. Check for known zero input bits. 1065 APInt NeededMask = DesiredMask & ~ActualMask; 1066 if (CurDAG->MaskedValueIsZero(LHS, NeededMask)) 1067 return true; 1068 1069 // TODO: check to see if missing bits are just not demanded. 1070 1071 // Otherwise, this pattern doesn't match. 1072 return false; 1073} 1074 1075/// CheckOrMask - The isel is trying to match something like (or X, 255). If 1076/// the dag combiner simplified the 255, we still want to match. RHS is the 1077/// actual value in the DAG on the RHS of an OR, and DesiredMaskS is the value 1078/// specified in the .td file (e.g. 255). 1079bool SelectionDAGISel::CheckOrMask(SDValue LHS, ConstantSDNode *RHS, 1080 int64_t DesiredMaskS) const { 1081 const APInt &ActualMask = RHS->getAPIntValue(); 1082 const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS); 1083 1084 // If the actual mask exactly matches, success! 1085 if (ActualMask == DesiredMask) 1086 return true; 1087 1088 // If the actual AND mask is allowing unallowed bits, this doesn't match. 1089 if (ActualMask.intersects(~DesiredMask)) 1090 return false; 1091 1092 // Otherwise, the DAG Combiner may have proven that the value coming in is 1093 // either already zero or is not demanded. Check for known zero input bits. 1094 APInt NeededMask = DesiredMask & ~ActualMask; 1095 1096 APInt KnownZero, KnownOne; 1097 CurDAG->ComputeMaskedBits(LHS, NeededMask, KnownZero, KnownOne); 1098 1099 // If all the missing bits in the or are already known to be set, match! 1100 if ((NeededMask & KnownOne) == NeededMask) 1101 return true; 1102 1103 // TODO: check to see if missing bits are just not demanded. 1104 1105 // Otherwise, this pattern doesn't match. 1106 return false; 1107} 1108 1109 1110/// SelectInlineAsmMemoryOperands - Calls to this are automatically generated 1111/// by tblgen. Others should not call it. 1112void SelectionDAGISel:: 1113SelectInlineAsmMemoryOperands(std::vector<SDValue> &Ops) { 1114 std::vector<SDValue> InOps; 1115 std::swap(InOps, Ops); 1116 1117 Ops.push_back(InOps[0]); // input chain. 1118 Ops.push_back(InOps[1]); // input asm string. 1119 1120 unsigned i = 2, e = InOps.size(); 1121 if (InOps[e-1].getValueType() == MVT::Flag) 1122 --e; // Don't process a flag operand if it is here. 1123 1124 while (i != e) { 1125 unsigned Flags = cast<ConstantSDNode>(InOps[i])->getZExtValue(); 1126 if ((Flags & 7) != 4 /*MEM*/) { 1127 // Just skip over this operand, copying the operands verbatim. 1128 Ops.insert(Ops.end(), InOps.begin()+i, InOps.begin()+i+(Flags >> 3) + 1); 1129 i += (Flags >> 3) + 1; 1130 } else { 1131 assert((Flags >> 3) == 1 && "Memory operand with multiple values?"); 1132 // Otherwise, this is a memory operand. Ask the target to select it. 1133 std::vector<SDValue> SelOps; 1134 if (SelectInlineAsmMemoryOperand(InOps[i+1], 'm', SelOps)) { 1135 cerr << "Could not match memory address. Inline asm failure!\n"; 1136 exit(1); 1137 } 1138 1139 // Add this to the output node. 1140 MVT IntPtrTy = CurDAG->getTargetLoweringInfo().getPointerTy(); 1141 Ops.push_back(CurDAG->getTargetConstant(4/*MEM*/ | (SelOps.size() << 3), 1142 IntPtrTy)); 1143 Ops.insert(Ops.end(), SelOps.begin(), SelOps.end()); 1144 i += 2; 1145 } 1146 } 1147 1148 // Add the flag input back if present. 1149 if (e != InOps.size()) 1150 Ops.push_back(InOps.back()); 1151} 1152 1153char SelectionDAGISel::ID = 0; 1154