1 //===-- SelectionDAGISel.cpp - Implement the SelectionDAGISel class -------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This implements the SelectionDAGISel class.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "isel"
15 #include "ScheduleDAGSDNodes.h"
16 #include "SelectionDAGBuild.h"
17 #include "llvm/CodeGen/SelectionDAGISel.h"
18 #include "llvm/Analysis/AliasAnalysis.h"
19 #include "llvm/Analysis/DebugInfo.h"
20 #include "llvm/Constants.h"
21 #include "llvm/CallingConv.h"
22 #include "llvm/DerivedTypes.h"
23 #include "llvm/Function.h"
24 #include "llvm/GlobalVariable.h"
25 #include "llvm/InlineAsm.h"
26 #include "llvm/Instructions.h"
27 #include "llvm/Intrinsics.h"
28 #include "llvm/IntrinsicInst.h"
29 #include "llvm/LLVMContext.h"
30 #include "llvm/CodeGen/FastISel.h"
31 #include "llvm/CodeGen/GCStrategy.h"
32 #include "llvm/CodeGen/GCMetadata.h"
33 #include "llvm/CodeGen/MachineFunction.h"
34 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
35 #include "llvm/CodeGen/MachineFrameInfo.h"
36 #include "llvm/CodeGen/MachineInstrBuilder.h"
37 #include "llvm/CodeGen/MachineJumpTableInfo.h"
38 #include "llvm/CodeGen/MachineModuleInfo.h"
39 #include "llvm/CodeGen/MachineRegisterInfo.h"
40 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
41 #include "llvm/CodeGen/SchedulerRegistry.h"
42 #include "llvm/CodeGen/SelectionDAG.h"
43 #include "llvm/CodeGen/DwarfWriter.h"
44 #include "llvm/Target/TargetRegisterInfo.h"
45 #include "llvm/Target/TargetData.h"
46 #include "llvm/Target/TargetFrameInfo.h"
47 #include "llvm/Target/TargetIntrinsicInfo.h"
48 #include "llvm/Target/TargetInstrInfo.h"
49 #include "llvm/Target/TargetLowering.h"
50 #include "llvm/Target/TargetMachine.h"
51 #include "llvm/Target/TargetOptions.h"
52 #include "llvm/Support/Compiler.h"
53 #include "llvm/Support/Debug.h"
54 #include "llvm/Support/ErrorHandling.h"
55 #include "llvm/Support/MathExtras.h"
56 #include "llvm/Support/Timer.h"
57 #include "llvm/Support/raw_ostream.h"
62 DisableLegalizeTypes("disable-legalize-types", cl::Hidden);
64 EnableFastISelVerbose("fast-isel-verbose", cl::Hidden,
65 cl::desc("Enable verbose messages in the \"fast\" "
66 "instruction selector"));
68 EnableFastISelAbort("fast-isel-abort", cl::Hidden,
69 cl::desc("Enable abort calls when \"fast\" instruction fails"));
71 SchedLiveInCopies("schedule-livein-copies", cl::Hidden,
72 cl::desc("Schedule copies of livein registers"),
77 ViewDAGCombine1("view-dag-combine1-dags", cl::Hidden,
78 cl::desc("Pop up a window to show dags before the first "
81 ViewLegalizeTypesDAGs("view-legalize-types-dags", cl::Hidden,
82 cl::desc("Pop up a window to show dags before legalize types"));
84 ViewLegalizeDAGs("view-legalize-dags", cl::Hidden,
85 cl::desc("Pop up a window to show dags before legalize"));
87 ViewDAGCombine2("view-dag-combine2-dags", cl::Hidden,
88 cl::desc("Pop up a window to show dags before the second "
91 ViewDAGCombineLT("view-dag-combine-lt-dags", cl::Hidden,
92 cl::desc("Pop up a window to show dags before the post legalize types"
93 " dag combine pass"));
95 ViewISelDAGs("view-isel-dags", cl::Hidden,
96 cl::desc("Pop up a window to show isel dags as they are selected"));
98 ViewSchedDAGs("view-sched-dags", cl::Hidden,
99 cl::desc("Pop up a window to show sched dags as they are processed"));
101 ViewSUnitDAGs("view-sunit-dags", cl::Hidden,
102 cl::desc("Pop up a window to show SUnit dags after they are processed"));
104 static const bool ViewDAGCombine1 = false,
105 ViewLegalizeTypesDAGs = false, ViewLegalizeDAGs = false,
106 ViewDAGCombine2 = false,
107 ViewDAGCombineLT = false,
108 ViewISelDAGs = false, ViewSchedDAGs = false,
109 ViewSUnitDAGs = false;
112 //===---------------------------------------------------------------------===//
114 /// RegisterScheduler class - Track the registration of instruction schedulers.
116 //===---------------------------------------------------------------------===//
117 MachinePassRegistry RegisterScheduler::Registry;
119 //===---------------------------------------------------------------------===//
121 /// ISHeuristic command line option for instruction schedulers.
123 //===---------------------------------------------------------------------===//
124 static cl::opt<RegisterScheduler::FunctionPassCtor, false,
125 RegisterPassParser<RegisterScheduler> >
126 ISHeuristic("pre-RA-sched",
127 cl::init(&createDefaultScheduler),
128 cl::desc("Instruction schedulers available (before register"
131 static RegisterScheduler
132 defaultListDAGScheduler("default", "Best scheduler for the target",
133 createDefaultScheduler);
136 //===--------------------------------------------------------------------===//
137 /// createDefaultScheduler - This creates an instruction scheduler appropriate
139 ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
140 CodeGenOpt::Level OptLevel) {
141 const TargetLowering &TLI = IS->getTargetLowering();
143 if (OptLevel == CodeGenOpt::None)
144 return createFastDAGScheduler(IS, OptLevel);
145 if (TLI.getSchedulingPreference() == TargetLowering::SchedulingForLatency)
146 return createTDListDAGScheduler(IS, OptLevel);
147 assert(TLI.getSchedulingPreference() ==
148 TargetLowering::SchedulingForRegPressure && "Unknown sched type!");
149 return createBURRListDAGScheduler(IS, OptLevel);
153 // EmitInstrWithCustomInserter - This method should be implemented by targets
154 // that mark instructions with the 'usesCustomInserter' flag. These
155 // instructions are special in various ways, which require special support to
156 // insert. The specified MachineInstr is created but not inserted into any
157 // basic blocks, and this method is called to expand it into a sequence of
158 // instructions, potentially also creating new basic blocks and control flow.
159 // When new basic blocks are inserted and the edges from MBB to its successors
160 // are modified, the method should insert pairs of <OldSucc, NewSucc> into the
162 MachineBasicBlock *TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
163 MachineBasicBlock *MBB,
164 DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const {
166 errs() << "If a target marks an instruction with "
167 "'usesCustomInserter', it must implement "
168 "TargetLowering::EmitInstrWithCustomInserter!";
174 /// EmitLiveInCopy - Emit a copy for a live in physical register. If the
175 /// physical register has only a single copy use, then coalesced the copy
177 static void EmitLiveInCopy(MachineBasicBlock *MBB,
178 MachineBasicBlock::iterator &InsertPos,
179 unsigned VirtReg, unsigned PhysReg,
180 const TargetRegisterClass *RC,
181 DenseMap<MachineInstr*, unsigned> &CopyRegMap,
182 const MachineRegisterInfo &MRI,
183 const TargetRegisterInfo &TRI,
184 const TargetInstrInfo &TII) {
185 unsigned NumUses = 0;
186 MachineInstr *UseMI = NULL;
187 for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg),
188 UE = MRI.use_end(); UI != UE; ++UI) {
194 // If the number of uses is not one, or the use is not a move instruction,
195 // don't coalesce. Also, only coalesce away a virtual register to virtual
197 bool Coalesced = false;
198 unsigned SrcReg, DstReg, SrcSubReg, DstSubReg;
200 TII.isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubReg, DstSubReg) &&
201 TargetRegisterInfo::isVirtualRegister(DstReg)) {
206 // Now find an ideal location to insert the copy.
207 MachineBasicBlock::iterator Pos = InsertPos;
208 while (Pos != MBB->begin()) {
209 MachineInstr *PrevMI = prior(Pos);
210 DenseMap<MachineInstr*, unsigned>::iterator RI = CopyRegMap.find(PrevMI);
211 // copyRegToReg might emit multiple instructions to do a copy.
212 unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second;
213 if (CopyDstReg && !TRI.regsOverlap(CopyDstReg, PhysReg))
214 // This is what the BB looks like right now:
219 // We want to insert "r1025 = mov r1". Inserting this copy below the
220 // move to r1024 makes it impossible for that move to be coalesced.
227 break; // Woot! Found a good location.
231 bool Emitted = TII.copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC);
232 assert(Emitted && "Unable to issue a live-in copy instruction!\n");
235 CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg));
237 if (&*InsertPos == UseMI) ++InsertPos;
242 /// EmitLiveInCopies - If this is the first basic block in the function,
243 /// and if it has live ins that need to be copied into vregs, emit the
244 /// copies into the block.
245 static void EmitLiveInCopies(MachineBasicBlock *EntryMBB,
246 const MachineRegisterInfo &MRI,
247 const TargetRegisterInfo &TRI,
248 const TargetInstrInfo &TII) {
249 if (SchedLiveInCopies) {
250 // Emit the copies at a heuristically-determined location in the block.
251 DenseMap<MachineInstr*, unsigned> CopyRegMap;
252 MachineBasicBlock::iterator InsertPos = EntryMBB->begin();
253 for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(),
254 E = MRI.livein_end(); LI != E; ++LI)
256 const TargetRegisterClass *RC = MRI.getRegClass(LI->second);
257 EmitLiveInCopy(EntryMBB, InsertPos, LI->second, LI->first,
258 RC, CopyRegMap, MRI, TRI, TII);
261 // Emit the copies into the top of the block.
262 for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(),
263 E = MRI.livein_end(); LI != E; ++LI)
265 const TargetRegisterClass *RC = MRI.getRegClass(LI->second);
266 bool Emitted = TII.copyRegToReg(*EntryMBB, EntryMBB->begin(),
267 LI->second, LI->first, RC, RC);
268 assert(Emitted && "Unable to issue a live-in copy instruction!\n");
274 //===----------------------------------------------------------------------===//
275 // SelectionDAGISel code
276 //===----------------------------------------------------------------------===//
278 SelectionDAGISel::SelectionDAGISel(TargetMachine &tm, CodeGenOpt::Level OL) :
279 MachineFunctionPass(&ID), TM(tm), TLI(*tm.getTargetLowering()),
280 FuncInfo(new FunctionLoweringInfo(TLI)),
281 CurDAG(new SelectionDAG(TLI, *FuncInfo)),
282 SDL(new SelectionDAGLowering(*CurDAG, TLI, *FuncInfo, OL)),
288 SelectionDAGISel::~SelectionDAGISel() {
294 unsigned SelectionDAGISel::MakeReg(EVT VT) {
295 return RegInfo->createVirtualRegister(TLI.getRegClassFor(VT));
298 void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
299 AU.addRequired<AliasAnalysis>();
300 AU.addPreserved<AliasAnalysis>();
301 AU.addRequired<GCModuleInfo>();
302 AU.addPreserved<GCModuleInfo>();
303 AU.addRequired<DwarfWriter>();
304 AU.addPreserved<DwarfWriter>();
305 MachineFunctionPass::getAnalysisUsage(AU);
308 bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
309 Function &Fn = *mf.getFunction();
311 // Do some sanity-checking on the command-line options.
312 assert((!EnableFastISelVerbose || EnableFastISel) &&
313 "-fast-isel-verbose requires -fast-isel");
314 assert((!EnableFastISelAbort || EnableFastISel) &&
315 "-fast-isel-abort requires -fast-isel");
317 // Get alias analysis for load/store combining.
318 AA = &getAnalysis<AliasAnalysis>();
321 const TargetInstrInfo &TII = *TM.getInstrInfo();
322 const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
325 GFI = &getAnalysis<GCModuleInfo>().getFunctionInfo(Fn);
328 RegInfo = &MF->getRegInfo();
329 DEBUG(errs() << "\n\n\n=== " << Fn.getName() << "\n");
331 MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
332 DwarfWriter *DW = getAnalysisIfAvailable<DwarfWriter>();
333 CurDAG->init(*MF, MMI, DW);
334 FuncInfo->set(Fn, *MF, *CurDAG, EnableFastISel);
337 for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
338 if (InvokeInst *Invoke = dyn_cast<InvokeInst>(I->getTerminator()))
340 FuncInfo->MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
342 SelectAllBasicBlocks(Fn, *MF, MMI, DW, TII);
344 // If the first basic block in the function has live ins that need to be
345 // copied into vregs, emit the copies into the top of the block before
346 // emitting the code for the block.
347 EmitLiveInCopies(MF->begin(), *RegInfo, TRI, TII);
349 // Add function live-ins to entry block live-in set.
350 for (MachineRegisterInfo::livein_iterator I = RegInfo->livein_begin(),
351 E = RegInfo->livein_end(); I != E; ++I)
352 MF->begin()->addLiveIn(I->first);
355 assert(FuncInfo->CatchInfoFound.size() == FuncInfo->CatchInfoLost.size() &&
356 "Not all catch info was assigned to a landing pad!");
364 static void copyCatchInfo(BasicBlock *SrcBB, BasicBlock *DestBB,
365 MachineModuleInfo *MMI, FunctionLoweringInfo &FLI) {
366 for (BasicBlock::iterator I = SrcBB->begin(), E = --SrcBB->end(); I != E; ++I)
367 if (EHSelectorInst *EHSel = dyn_cast<EHSelectorInst>(I)) {
368 // Apply the catch info to DestBB.
369 AddCatchInfo(*EHSel, MMI, FLI.MBBMap[DestBB]);
371 if (!FLI.MBBMap[SrcBB]->isLandingPad())
372 FLI.CatchInfoFound.insert(EHSel);
377 void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB,
378 BasicBlock::iterator Begin,
379 BasicBlock::iterator End) {
380 SDL->setCurrentBasicBlock(BB);
381 MetadataContext &TheMetadata = LLVMBB->getParent()->getContext().getMetadata();
382 unsigned MDDbgKind = TheMetadata.getMDKind("dbg");
384 // Lower all of the non-terminator instructions. If a call is emitted
385 // as a tail call, cease emitting nodes for this block.
386 for (BasicBlock::iterator I = Begin; I != End && !SDL->HasTailCall; ++I) {
388 // Update DebugLoc if debug information is attached with this
390 if (!isa<DbgInfoIntrinsic>(I))
391 if (MDNode *Dbg = TheMetadata.getMD(MDDbgKind, I)) {
392 DILocation DILoc(Dbg);
393 DebugLoc Loc = ExtractDebugLocation(DILoc, MF->getDebugLocInfo());
394 SDL->setCurDebugLoc(Loc);
395 if (MF->getDefaultDebugLoc().isUnknown())
396 MF->setDefaultDebugLoc(Loc);
399 if (!isa<TerminatorInst>(I))
403 if (!SDL->HasTailCall) {
404 // Ensure that all instructions which are used outside of their defining
405 // blocks are available as virtual registers. Invoke is handled elsewhere.
406 for (BasicBlock::iterator I = Begin; I != End; ++I)
407 if (!isa<PHINode>(I) && !isa<InvokeInst>(I))
408 SDL->CopyToExportRegsIfNeeded(I);
410 // Handle PHI nodes in successor blocks.
411 if (End == LLVMBB->end()) {
412 HandlePHINodesInSuccessorBlocks(LLVMBB);
414 // Lower the terminator after the copies are emitted.
415 SDL->visit(*LLVMBB->getTerminator());
419 // Make sure the root of the DAG is up-to-date.
420 CurDAG->setRoot(SDL->getControlRoot());
422 // Final step, emit the lowered DAG as machine code.
427 void SelectionDAGISel::ComputeLiveOutVRegInfo() {
428 SmallPtrSet<SDNode*, 128> VisitedNodes;
429 SmallVector<SDNode*, 128> Worklist;
431 Worklist.push_back(CurDAG->getRoot().getNode());
437 while (!Worklist.empty()) {
438 SDNode *N = Worklist.back();
441 // If we've already seen this node, ignore it.
442 if (!VisitedNodes.insert(N))
445 // Otherwise, add all chain operands to the worklist.
446 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
447 if (N->getOperand(i).getValueType() == MVT::Other)
448 Worklist.push_back(N->getOperand(i).getNode());
450 // If this is a CopyToReg with a vreg dest, process it.
451 if (N->getOpcode() != ISD::CopyToReg)
454 unsigned DestReg = cast<RegisterSDNode>(N->getOperand(1))->getReg();
455 if (!TargetRegisterInfo::isVirtualRegister(DestReg))
458 // Ignore non-scalar or non-integer values.
459 SDValue Src = N->getOperand(2);
460 EVT SrcVT = Src.getValueType();
461 if (!SrcVT.isInteger() || SrcVT.isVector())
464 unsigned NumSignBits = CurDAG->ComputeNumSignBits(Src);
465 Mask = APInt::getAllOnesValue(SrcVT.getSizeInBits());
466 CurDAG->ComputeMaskedBits(Src, Mask, KnownZero, KnownOne);
468 // Only install this information if it tells us something.
469 if (NumSignBits != 1 || KnownZero != 0 || KnownOne != 0) {
470 DestReg -= TargetRegisterInfo::FirstVirtualRegister;
471 if (DestReg >= FuncInfo->LiveOutRegInfo.size())
472 FuncInfo->LiveOutRegInfo.resize(DestReg+1);
473 FunctionLoweringInfo::LiveOutInfo &LOI =
474 FuncInfo->LiveOutRegInfo[DestReg];
475 LOI.NumSignBits = NumSignBits;
476 LOI.KnownOne = KnownOne;
477 LOI.KnownZero = KnownZero;
482 void SelectionDAGISel::CodeGenAndEmitDAG() {
483 std::string GroupName;
484 if (TimePassesIsEnabled)
485 GroupName = "Instruction Selection and Scheduling";
486 std::string BlockName;
487 if (ViewDAGCombine1 || ViewLegalizeTypesDAGs || ViewLegalizeDAGs ||
488 ViewDAGCombine2 || ViewDAGCombineLT || ViewISelDAGs || ViewSchedDAGs ||
490 BlockName = MF->getFunction()->getNameStr() + ":" +
491 BB->getBasicBlock()->getNameStr();
493 DEBUG(errs() << "Initial selection DAG:\n");
494 DEBUG(CurDAG->dump());
496 if (ViewDAGCombine1) CurDAG->viewGraph("dag-combine1 input for " + BlockName);
498 // Run the DAG combiner in pre-legalize mode.
499 if (TimePassesIsEnabled) {
500 NamedRegionTimer T("DAG Combining 1", GroupName);
501 CurDAG->Combine(Unrestricted, *AA, OptLevel);
503 CurDAG->Combine(Unrestricted, *AA, OptLevel);
506 DEBUG(errs() << "Optimized lowered selection DAG:\n");
507 DEBUG(CurDAG->dump());
509 // Second step, hack on the DAG until it only uses operations and types that
510 // the target supports.
511 if (!DisableLegalizeTypes) {
512 if (ViewLegalizeTypesDAGs) CurDAG->viewGraph("legalize-types input for " +
516 if (TimePassesIsEnabled) {
517 NamedRegionTimer T("Type Legalization", GroupName);
518 Changed = CurDAG->LegalizeTypes();
520 Changed = CurDAG->LegalizeTypes();
523 DEBUG(errs() << "Type-legalized selection DAG:\n");
524 DEBUG(CurDAG->dump());
527 if (ViewDAGCombineLT)
528 CurDAG->viewGraph("dag-combine-lt input for " + BlockName);
530 // Run the DAG combiner in post-type-legalize mode.
531 if (TimePassesIsEnabled) {
532 NamedRegionTimer T("DAG Combining after legalize types", GroupName);
533 CurDAG->Combine(NoIllegalTypes, *AA, OptLevel);
535 CurDAG->Combine(NoIllegalTypes, *AA, OptLevel);
538 DEBUG(errs() << "Optimized type-legalized selection DAG:\n");
539 DEBUG(CurDAG->dump());
542 if (TimePassesIsEnabled) {
543 NamedRegionTimer T("Vector Legalization", GroupName);
544 Changed = CurDAG->LegalizeVectors();
546 Changed = CurDAG->LegalizeVectors();
550 if (TimePassesIsEnabled) {
551 NamedRegionTimer T("Type Legalization 2", GroupName);
552 Changed = CurDAG->LegalizeTypes();
554 Changed = CurDAG->LegalizeTypes();
557 if (ViewDAGCombineLT)
558 CurDAG->viewGraph("dag-combine-lv input for " + BlockName);
560 // Run the DAG combiner in post-type-legalize mode.
561 if (TimePassesIsEnabled) {
562 NamedRegionTimer T("DAG Combining after legalize vectors", GroupName);
563 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
565 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
568 DEBUG(errs() << "Optimized vector-legalized selection DAG:\n");
569 DEBUG(CurDAG->dump());
573 if (ViewLegalizeDAGs) CurDAG->viewGraph("legalize input for " + BlockName);
575 if (TimePassesIsEnabled) {
576 NamedRegionTimer T("DAG Legalization", GroupName);
577 CurDAG->Legalize(DisableLegalizeTypes, OptLevel);
579 CurDAG->Legalize(DisableLegalizeTypes, OptLevel);
582 DEBUG(errs() << "Legalized selection DAG:\n");
583 DEBUG(CurDAG->dump());
585 if (ViewDAGCombine2) CurDAG->viewGraph("dag-combine2 input for " + BlockName);
587 // Run the DAG combiner in post-legalize mode.
588 if (TimePassesIsEnabled) {
589 NamedRegionTimer T("DAG Combining 2", GroupName);
590 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
592 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
595 DEBUG(errs() << "Optimized legalized selection DAG:\n");
596 DEBUG(CurDAG->dump());
598 if (ViewISelDAGs) CurDAG->viewGraph("isel input for " + BlockName);
600 if (OptLevel != CodeGenOpt::None)
601 ComputeLiveOutVRegInfo();
603 // Third, instruction select all of the operations to machine code, adding the
604 // code to the MachineBasicBlock.
605 if (TimePassesIsEnabled) {
606 NamedRegionTimer T("Instruction Selection", GroupName);
612 DEBUG(errs() << "Selected selection DAG:\n");
613 DEBUG(CurDAG->dump());
615 if (ViewSchedDAGs) CurDAG->viewGraph("scheduler input for " + BlockName);
617 // Schedule machine code.
618 ScheduleDAGSDNodes *Scheduler = CreateScheduler();
619 if (TimePassesIsEnabled) {
620 NamedRegionTimer T("Instruction Scheduling", GroupName);
621 Scheduler->Run(CurDAG, BB, BB->end());
623 Scheduler->Run(CurDAG, BB, BB->end());
626 if (ViewSUnitDAGs) Scheduler->viewGraph();
628 // Emit machine code to BB. This can change 'BB' to the last block being
630 if (TimePassesIsEnabled) {
631 NamedRegionTimer T("Instruction Creation", GroupName);
632 BB = Scheduler->EmitSchedule(&SDL->EdgeMapping);
634 BB = Scheduler->EmitSchedule(&SDL->EdgeMapping);
637 // Free the scheduler state.
638 if (TimePassesIsEnabled) {
639 NamedRegionTimer T("Instruction Scheduling Cleanup", GroupName);
645 DEBUG(errs() << "Selected machine code:\n");
649 void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn,
651 MachineModuleInfo *MMI,
653 const TargetInstrInfo &TII) {
654 // Initialize the Fast-ISel state, if needed.
655 FastISel *FastIS = 0;
657 FastIS = TLI.createFastISel(MF, MMI, DW,
660 FuncInfo->StaticAllocaMap
662 , FuncInfo->CatchInfoLost
666 MetadataContext &TheMetadata = Fn.getContext().getMetadata();
667 unsigned MDDbgKind = TheMetadata.getMDKind("dbg");
669 // Iterate over all basic blocks in the function.
670 for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
671 BasicBlock *LLVMBB = &*I;
672 BB = FuncInfo->MBBMap[LLVMBB];
674 BasicBlock::iterator const Begin = LLVMBB->begin();
675 BasicBlock::iterator const End = LLVMBB->end();
676 BasicBlock::iterator BI = Begin;
678 // Lower any arguments needed in this block if this is the entry block.
679 bool SuppressFastISel = false;
680 if (LLVMBB == &Fn.getEntryBlock()) {
681 LowerArguments(LLVMBB);
683 // If any of the arguments has the byval attribute, forgo
684 // fast-isel in the entry block.
687 for (Function::arg_iterator I = Fn.arg_begin(), E = Fn.arg_end();
689 if (Fn.paramHasAttr(j, Attribute::ByVal)) {
690 if (EnableFastISelVerbose || EnableFastISelAbort)
691 errs() << "FastISel skips entry block due to byval argument\n";
692 SuppressFastISel = true;
698 if (MMI && BB->isLandingPad()) {
699 // Add a label to mark the beginning of the landing pad. Deletion of the
700 // landing pad can thus be detected via the MachineModuleInfo.
701 unsigned LabelID = MMI->addLandingPad(BB);
703 const TargetInstrDesc &II = TII.get(TargetInstrInfo::EH_LABEL);
704 BuildMI(BB, SDL->getCurDebugLoc(), II).addImm(LabelID);
706 // Mark exception register as live in.
707 unsigned Reg = TLI.getExceptionAddressRegister();
708 if (Reg) BB->addLiveIn(Reg);
710 // Mark exception selector register as live in.
711 Reg = TLI.getExceptionSelectorRegister();
712 if (Reg) BB->addLiveIn(Reg);
714 // FIXME: Hack around an exception handling flaw (PR1508): the personality
715 // function and list of typeids logically belong to the invoke (or, if you
716 // like, the basic block containing the invoke), and need to be associated
717 // with it in the dwarf exception handling tables. Currently however the
718 // information is provided by an intrinsic (eh.selector) that can be moved
719 // to unexpected places by the optimizers: if the unwind edge is critical,
720 // then breaking it can result in the intrinsics being in the successor of
721 // the landing pad, not the landing pad itself. This results in exceptions
722 // not being caught because no typeids are associated with the invoke.
723 // This may not be the only way things can go wrong, but it is the only way
724 // we try to work around for the moment.
725 BranchInst *Br = dyn_cast<BranchInst>(LLVMBB->getTerminator());
727 if (Br && Br->isUnconditional()) { // Critical edge?
728 BasicBlock::iterator I, E;
729 for (I = LLVMBB->begin(), E = --LLVMBB->end(); I != E; ++I)
730 if (isa<EHSelectorInst>(I))
734 // No catch info found - try to extract some from the successor.
735 copyCatchInfo(Br->getSuccessor(0), LLVMBB, MMI, *FuncInfo);
739 // Before doing SelectionDAG ISel, see if FastISel has been requested.
740 if (FastIS && !SuppressFastISel) {
741 // Emit code for any incoming arguments. This must happen before
742 // beginning FastISel on the entry block.
743 if (LLVMBB == &Fn.getEntryBlock()) {
744 CurDAG->setRoot(SDL->getControlRoot());
748 FastIS->startNewBlock(BB);
749 // Do FastISel on as many instructions as possible.
750 for (; BI != End; ++BI) {
752 // Update DebugLoc if debug information is attached with this
754 if (!isa<DbgInfoIntrinsic>(BI))
755 if (MDNode *Dbg = TheMetadata.getMD(MDDbgKind, BI)) {
756 DILocation DILoc(Dbg);
757 DebugLoc Loc = ExtractDebugLocation(DILoc,
758 MF.getDebugLocInfo());
759 FastIS->setCurDebugLoc(Loc);
760 if (MF.getDefaultDebugLoc().isUnknown())
761 MF.setDefaultDebugLoc(Loc);
765 // Just before the terminator instruction, insert instructions to
766 // feed PHI nodes in successor blocks.
767 if (isa<TerminatorInst>(BI))
768 if (!HandlePHINodesInSuccessorBlocksFast(LLVMBB, FastIS)) {
769 if (EnableFastISelVerbose || EnableFastISelAbort) {
770 errs() << "FastISel miss: ";
773 assert(!EnableFastISelAbort &&
774 "FastISel didn't handle a PHI in a successor");
778 // First try normal tablegen-generated "fast" selection.
779 if (FastIS->SelectInstruction(BI))
782 // Next, try calling the target to attempt to handle the instruction.
783 if (FastIS->TargetSelectInstruction(BI))
786 // Then handle certain instructions as single-LLVM-Instruction blocks.
787 if (isa<CallInst>(BI)) {
788 if (EnableFastISelVerbose || EnableFastISelAbort) {
789 errs() << "FastISel missed call: ";
793 if (BI->getType() != Type::getVoidTy(*CurDAG->getContext())) {
794 unsigned &R = FuncInfo->ValueMap[BI];
796 R = FuncInfo->CreateRegForValue(BI);
799 SDL->setCurDebugLoc(FastIS->getCurDebugLoc());
800 SelectBasicBlock(LLVMBB, BI, next(BI));
801 // If the instruction was codegen'd with multiple blocks,
802 // inform the FastISel object where to resume inserting.
803 FastIS->setCurrentBlock(BB);
807 // Otherwise, give up on FastISel for the rest of the block.
808 // For now, be a little lenient about non-branch terminators.
809 if (!isa<TerminatorInst>(BI) || isa<BranchInst>(BI)) {
810 if (EnableFastISelVerbose || EnableFastISelAbort) {
811 errs() << "FastISel miss: ";
814 if (EnableFastISelAbort)
815 // The "fast" selector couldn't handle something and bailed.
816 // For the purpose of debugging, just abort.
817 llvm_unreachable("FastISel didn't select the entire block");
823 // Run SelectionDAG instruction selection on the remainder of the block
824 // not handled by FastISel. If FastISel is not run, this is the entire
827 // If FastISel is run and it has known DebugLoc then use it.
828 if (FastIS && !FastIS->getCurDebugLoc().isUnknown())
829 SDL->setCurDebugLoc(FastIS->getCurDebugLoc());
830 SelectBasicBlock(LLVMBB, BI, End);
840 SelectionDAGISel::FinishBasicBlock() {
842 DEBUG(errs() << "Target-post-processed machine code:\n");
845 DEBUG(errs() << "Total amount of phi nodes to update: "
846 << SDL->PHINodesToUpdate.size() << "\n");
847 DEBUG(for (unsigned i = 0, e = SDL->PHINodesToUpdate.size(); i != e; ++i)
848 errs() << "Node " << i << " : ("
849 << SDL->PHINodesToUpdate[i].first
850 << ", " << SDL->PHINodesToUpdate[i].second << ")\n");
852 // Next, now that we know what the last MBB the LLVM BB expanded is, update
853 // PHI nodes in successors.
854 if (SDL->SwitchCases.empty() &&
855 SDL->JTCases.empty() &&
856 SDL->BitTestCases.empty()) {
857 for (unsigned i = 0, e = SDL->PHINodesToUpdate.size(); i != e; ++i) {
858 MachineInstr *PHI = SDL->PHINodesToUpdate[i].first;
859 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
860 "This is not a machine PHI node that we are updating!");
861 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[i].second,
863 PHI->addOperand(MachineOperand::CreateMBB(BB));
865 SDL->PHINodesToUpdate.clear();
869 for (unsigned i = 0, e = SDL->BitTestCases.size(); i != e; ++i) {
870 // Lower header first, if it wasn't already lowered
871 if (!SDL->BitTestCases[i].Emitted) {
872 // Set the current basic block to the mbb we wish to insert the code into
873 BB = SDL->BitTestCases[i].Parent;
874 SDL->setCurrentBasicBlock(BB);
876 SDL->visitBitTestHeader(SDL->BitTestCases[i]);
877 CurDAG->setRoot(SDL->getRoot());
882 for (unsigned j = 0, ej = SDL->BitTestCases[i].Cases.size(); j != ej; ++j) {
883 // Set the current basic block to the mbb we wish to insert the code into
884 BB = SDL->BitTestCases[i].Cases[j].ThisBB;
885 SDL->setCurrentBasicBlock(BB);
888 SDL->visitBitTestCase(SDL->BitTestCases[i].Cases[j+1].ThisBB,
889 SDL->BitTestCases[i].Reg,
890 SDL->BitTestCases[i].Cases[j]);
892 SDL->visitBitTestCase(SDL->BitTestCases[i].Default,
893 SDL->BitTestCases[i].Reg,
894 SDL->BitTestCases[i].Cases[j]);
897 CurDAG->setRoot(SDL->getRoot());
903 for (unsigned pi = 0, pe = SDL->PHINodesToUpdate.size(); pi != pe; ++pi) {
904 MachineInstr *PHI = SDL->PHINodesToUpdate[pi].first;
905 MachineBasicBlock *PHIBB = PHI->getParent();
906 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
907 "This is not a machine PHI node that we are updating!");
908 // This is "default" BB. We have two jumps to it. From "header" BB and
909 // from last "case" BB.
910 if (PHIBB == SDL->BitTestCases[i].Default) {
911 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second,
913 PHI->addOperand(MachineOperand::CreateMBB(SDL->BitTestCases[i].Parent));
914 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second,
916 PHI->addOperand(MachineOperand::CreateMBB(SDL->BitTestCases[i].Cases.
919 // One of "cases" BB.
920 for (unsigned j = 0, ej = SDL->BitTestCases[i].Cases.size();
922 MachineBasicBlock* cBB = SDL->BitTestCases[i].Cases[j].ThisBB;
923 if (cBB->succ_end() !=
924 std::find(cBB->succ_begin(),cBB->succ_end(), PHIBB)) {
925 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second,
927 PHI->addOperand(MachineOperand::CreateMBB(cBB));
932 SDL->BitTestCases.clear();
934 // If the JumpTable record is filled in, then we need to emit a jump table.
935 // Updating the PHI nodes is tricky in this case, since we need to determine
936 // whether the PHI is a successor of the range check MBB or the jump table MBB
937 for (unsigned i = 0, e = SDL->JTCases.size(); i != e; ++i) {
938 // Lower header first, if it wasn't already lowered
939 if (!SDL->JTCases[i].first.Emitted) {
940 // Set the current basic block to the mbb we wish to insert the code into
941 BB = SDL->JTCases[i].first.HeaderBB;
942 SDL->setCurrentBasicBlock(BB);
944 SDL->visitJumpTableHeader(SDL->JTCases[i].second, SDL->JTCases[i].first);
945 CurDAG->setRoot(SDL->getRoot());
950 // Set the current basic block to the mbb we wish to insert the code into
951 BB = SDL->JTCases[i].second.MBB;
952 SDL->setCurrentBasicBlock(BB);
954 SDL->visitJumpTable(SDL->JTCases[i].second);
955 CurDAG->setRoot(SDL->getRoot());
960 for (unsigned pi = 0, pe = SDL->PHINodesToUpdate.size(); pi != pe; ++pi) {
961 MachineInstr *PHI = SDL->PHINodesToUpdate[pi].first;
962 MachineBasicBlock *PHIBB = PHI->getParent();
963 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
964 "This is not a machine PHI node that we are updating!");
965 // "default" BB. We can go there only from header BB.
966 if (PHIBB == SDL->JTCases[i].second.Default) {
968 (MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, false));
970 (MachineOperand::CreateMBB(SDL->JTCases[i].first.HeaderBB));
972 // JT BB. Just iterate over successors here
973 if (BB->succ_end() != std::find(BB->succ_begin(),BB->succ_end(), PHIBB)) {
975 (MachineOperand::CreateReg(SDL->PHINodesToUpdate[pi].second, false));
976 PHI->addOperand(MachineOperand::CreateMBB(BB));
980 SDL->JTCases.clear();
982 // If the switch block involved a branch to one of the actual successors, we
983 // need to update PHI nodes in that block.
984 for (unsigned i = 0, e = SDL->PHINodesToUpdate.size(); i != e; ++i) {
985 MachineInstr *PHI = SDL->PHINodesToUpdate[i].first;
986 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
987 "This is not a machine PHI node that we are updating!");
988 if (BB->isSuccessor(PHI->getParent())) {
989 PHI->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[i].second,
991 PHI->addOperand(MachineOperand::CreateMBB(BB));
995 // If we generated any switch lowering information, build and codegen any
996 // additional DAGs necessary.
997 for (unsigned i = 0, e = SDL->SwitchCases.size(); i != e; ++i) {
998 // Set the current basic block to the mbb we wish to insert the code into
999 MachineBasicBlock *ThisBB = BB = SDL->SwitchCases[i].ThisBB;
1000 SDL->setCurrentBasicBlock(BB);
1003 SDL->visitSwitchCase(SDL->SwitchCases[i]);
1004 CurDAG->setRoot(SDL->getRoot());
1005 CodeGenAndEmitDAG();
1007 // Handle any PHI nodes in successors of this chunk, as if we were coming
1008 // from the original BB before switch expansion. Note that PHI nodes can
1009 // occur multiple times in PHINodesToUpdate. We have to be very careful to
1010 // handle them the right number of times.
1011 while ((BB = SDL->SwitchCases[i].TrueBB)) { // Handle LHS and RHS.
1012 // If new BB's are created during scheduling, the edges may have been
1013 // updated. That is, the edge from ThisBB to BB may have been split and
1014 // BB's predecessor is now another block.
1015 DenseMap<MachineBasicBlock*, MachineBasicBlock*>::iterator EI =
1016 SDL->EdgeMapping.find(BB);
1017 if (EI != SDL->EdgeMapping.end())
1018 ThisBB = EI->second;
1019 for (MachineBasicBlock::iterator Phi = BB->begin();
1020 Phi != BB->end() && Phi->getOpcode() == TargetInstrInfo::PHI; ++Phi){
1021 // This value for this PHI node is recorded in PHINodesToUpdate, get it.
1022 for (unsigned pn = 0; ; ++pn) {
1023 assert(pn != SDL->PHINodesToUpdate.size() &&
1024 "Didn't find PHI entry!");
1025 if (SDL->PHINodesToUpdate[pn].first == Phi) {
1026 Phi->addOperand(MachineOperand::CreateReg(SDL->PHINodesToUpdate[pn].
1028 Phi->addOperand(MachineOperand::CreateMBB(ThisBB));
1034 // Don't process RHS if same block as LHS.
1035 if (BB == SDL->SwitchCases[i].FalseBB)
1036 SDL->SwitchCases[i].FalseBB = 0;
1038 // If we haven't handled the RHS, do so now. Otherwise, we're done.
1039 SDL->SwitchCases[i].TrueBB = SDL->SwitchCases[i].FalseBB;
1040 SDL->SwitchCases[i].FalseBB = 0;
1042 assert(SDL->SwitchCases[i].TrueBB == 0 && SDL->SwitchCases[i].FalseBB == 0);
1045 SDL->SwitchCases.clear();
1047 SDL->PHINodesToUpdate.clear();
1051 /// Create the scheduler. If a specific scheduler was specified
1052 /// via the SchedulerRegistry, use it, otherwise select the
1053 /// one preferred by the target.
1055 ScheduleDAGSDNodes *SelectionDAGISel::CreateScheduler() {
1056 RegisterScheduler::FunctionPassCtor Ctor = RegisterScheduler::getDefault();
1060 RegisterScheduler::setDefault(Ctor);
1063 return Ctor(this, OptLevel);
1066 ScheduleHazardRecognizer *SelectionDAGISel::CreateTargetHazardRecognizer() {
1067 return new ScheduleHazardRecognizer();
1070 //===----------------------------------------------------------------------===//
1071 // Helper functions used by the generated instruction selector.
1072 //===----------------------------------------------------------------------===//
1073 // Calls to these methods are generated by tblgen.
1075 /// CheckAndMask - The isel is trying to match something like (and 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 AND, and DesiredMaskS is the value
1078 /// specified in the .td file (e.g. 255).
1079 bool SelectionDAGISel::CheckAndMask(SDValue LHS, ConstantSDNode *RHS,
1080 int64_t DesiredMaskS) const {
1081 const APInt &ActualMask = RHS->getAPIntValue();
1082 const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS);
1084 // If the actual mask exactly matches, success!
1085 if (ActualMask == DesiredMask)
1088 // If the actual AND mask is allowing unallowed bits, this doesn't match.
1089 if (ActualMask.intersects(~DesiredMask))
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 if (CurDAG->MaskedValueIsZero(LHS, NeededMask))
1098 // TODO: check to see if missing bits are just not demanded.
1100 // Otherwise, this pattern doesn't match.
1104 /// CheckOrMask - The isel is trying to match something like (or X, 255). If
1105 /// the dag combiner simplified the 255, we still want to match. RHS is the
1106 /// actual value in the DAG on the RHS of an OR, and DesiredMaskS is the value
1107 /// specified in the .td file (e.g. 255).
1108 bool SelectionDAGISel::CheckOrMask(SDValue LHS, ConstantSDNode *RHS,
1109 int64_t DesiredMaskS) const {
1110 const APInt &ActualMask = RHS->getAPIntValue();
1111 const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS);
1113 // If the actual mask exactly matches, success!
1114 if (ActualMask == DesiredMask)
1117 // If the actual AND mask is allowing unallowed bits, this doesn't match.
1118 if (ActualMask.intersects(~DesiredMask))
1121 // Otherwise, the DAG Combiner may have proven that the value coming in is
1122 // either already zero or is not demanded. Check for known zero input bits.
1123 APInt NeededMask = DesiredMask & ~ActualMask;
1125 APInt KnownZero, KnownOne;
1126 CurDAG->ComputeMaskedBits(LHS, NeededMask, KnownZero, KnownOne);
1128 // If all the missing bits in the or are already known to be set, match!
1129 if ((NeededMask & KnownOne) == NeededMask)
1132 // TODO: check to see if missing bits are just not demanded.
1134 // Otherwise, this pattern doesn't match.
1139 /// SelectInlineAsmMemoryOperands - Calls to this are automatically generated
1140 /// by tblgen. Others should not call it.
1141 void SelectionDAGISel::
1142 SelectInlineAsmMemoryOperands(std::vector<SDValue> &Ops) {
1143 std::vector<SDValue> InOps;
1144 std::swap(InOps, Ops);
1146 Ops.push_back(InOps[0]); // input chain.
1147 Ops.push_back(InOps[1]); // input asm string.
1149 unsigned i = 2, e = InOps.size();
1150 if (InOps[e-1].getValueType() == MVT::Flag)
1151 --e; // Don't process a flag operand if it is here.
1154 unsigned Flags = cast<ConstantSDNode>(InOps[i])->getZExtValue();
1155 if ((Flags & 7) != 4 /*MEM*/) {
1156 // Just skip over this operand, copying the operands verbatim.
1157 Ops.insert(Ops.end(), InOps.begin()+i,
1158 InOps.begin()+i+InlineAsm::getNumOperandRegisters(Flags) + 1);
1159 i += InlineAsm::getNumOperandRegisters(Flags) + 1;
1161 assert(InlineAsm::getNumOperandRegisters(Flags) == 1 &&
1162 "Memory operand with multiple values?");
1163 // Otherwise, this is a memory operand. Ask the target to select it.
1164 std::vector<SDValue> SelOps;
1165 if (SelectInlineAsmMemoryOperand(InOps[i+1], 'm', SelOps)) {
1166 llvm_report_error("Could not match memory address. Inline asm"
1170 // Add this to the output node.
1171 EVT IntPtrTy = TLI.getPointerTy();
1172 Ops.push_back(CurDAG->getTargetConstant(4/*MEM*/ | (SelOps.size()<< 3),
1174 Ops.insert(Ops.end(), SelOps.begin(), SelOps.end());
1179 // Add the flag input back if present.
1180 if (e != InOps.size())
1181 Ops.push_back(InOps.back());
1184 /// findFlagUse - Return use of EVT::Flag value produced by the specified
1187 static SDNode *findFlagUse(SDNode *N) {
1188 unsigned FlagResNo = N->getNumValues()-1;
1189 for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) {
1190 SDUse &Use = I.getUse();
1191 if (Use.getResNo() == FlagResNo)
1192 return Use.getUser();
1197 /// findNonImmUse - Return true if "Use" is a non-immediate use of "Def".
1198 /// This function recursively traverses up the operand chain, ignoring
1200 static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse,
1202 SmallPtrSet<SDNode*, 16> &Visited) {
1203 if (Use->getNodeId() < Def->getNodeId() ||
1204 !Visited.insert(Use))
1207 for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) {
1208 SDNode *N = Use->getOperand(i).getNode();
1210 if (Use == ImmedUse || Use == Root)
1211 continue; // We are not looking for immediate use.
1216 // Traverse up the operand chain.
1217 if (findNonImmUse(N, Def, ImmedUse, Root, Visited))
1223 /// isNonImmUse - Start searching from Root up the DAG to check is Def can
1224 /// be reached. Return true if that's the case. However, ignore direct uses
1225 /// by ImmedUse (which would be U in the example illustrated in
1226 /// IsLegalAndProfitableToFold) and by Root (which can happen in the store
1228 /// FIXME: to be really generic, we should allow direct use by any node
1229 /// that is being folded. But realisticly since we only fold loads which
1230 /// have one non-chain use, we only need to watch out for load/op/store
1231 /// and load/op/cmp case where the root (store / cmp) may reach the load via
1232 /// its chain operand.
1233 static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) {
1234 SmallPtrSet<SDNode*, 16> Visited;
1235 return findNonImmUse(Root, Def, ImmedUse, Root, Visited);
1238 /// IsLegalAndProfitableToFold - Returns true if the specific operand node N of
1239 /// U can be folded during instruction selection that starts at Root and
1240 /// folding N is profitable.
1241 bool SelectionDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U,
1242 SDNode *Root) const {
1243 if (OptLevel == CodeGenOpt::None) return false;
1245 // If Root use can somehow reach N through a path that that doesn't contain
1246 // U then folding N would create a cycle. e.g. In the following
1247 // diagram, Root can reach N through X. If N is folded into into Root, then
1248 // X is both a predecessor and a successor of U.
1259 // * indicates nodes to be folded together.
1261 // If Root produces a flag, then it gets (even more) interesting. Since it
1262 // will be "glued" together with its flag use in the scheduler, we need to
1263 // check if it might reach N.
1282 // If FU (flag use) indirectly reaches N (the load), and Root folds N
1283 // (call it Fold), then X is a predecessor of FU and a successor of
1284 // Fold. But since Fold and FU are flagged together, this will create
1285 // a cycle in the scheduling graph.
1287 EVT VT = Root->getValueType(Root->getNumValues()-1);
1288 while (VT == MVT::Flag) {
1289 SDNode *FU = findFlagUse(Root);
1293 VT = Root->getValueType(Root->getNumValues()-1);
1296 return !isNonImmUse(Root, N, U);
1299 SDNode *SelectionDAGISel::Select_INLINEASM(SDValue N) {
1300 std::vector<SDValue> Ops(N.getNode()->op_begin(), N.getNode()->op_end());
1301 SelectInlineAsmMemoryOperands(Ops);
1303 std::vector<EVT> VTs;
1304 VTs.push_back(MVT::Other);
1305 VTs.push_back(MVT::Flag);
1306 SDValue New = CurDAG->getNode(ISD::INLINEASM, N.getDebugLoc(),
1307 VTs, &Ops[0], Ops.size());
1308 return New.getNode();
1311 SDNode *SelectionDAGISel::Select_UNDEF(const SDValue &N) {
1312 return CurDAG->SelectNodeTo(N.getNode(), TargetInstrInfo::IMPLICIT_DEF,
1316 SDNode *SelectionDAGISel::Select_DBG_LABEL(const SDValue &N) {
1317 SDValue Chain = N.getOperand(0);
1318 unsigned C = cast<LabelSDNode>(N)->getLabelID();
1319 SDValue Tmp = CurDAG->getTargetConstant(C, MVT::i32);
1320 return CurDAG->SelectNodeTo(N.getNode(), TargetInstrInfo::DBG_LABEL,
1321 MVT::Other, Tmp, Chain);
1324 SDNode *SelectionDAGISel::Select_EH_LABEL(const SDValue &N) {
1325 SDValue Chain = N.getOperand(0);
1326 unsigned C = cast<LabelSDNode>(N)->getLabelID();
1327 SDValue Tmp = CurDAG->getTargetConstant(C, MVT::i32);
1328 return CurDAG->SelectNodeTo(N.getNode(), TargetInstrInfo::EH_LABEL,
1329 MVT::Other, Tmp, Chain);
1332 void SelectionDAGISel::CannotYetSelect(SDValue N) {
1334 raw_string_ostream Msg(msg);
1335 Msg << "Cannot yet select: ";
1336 N.getNode()->print(Msg, CurDAG);
1337 llvm_report_error(Msg.str());
1340 void SelectionDAGISel::CannotYetSelectIntrinsic(SDValue N) {
1341 errs() << "Cannot yet select: ";
1343 cast<ConstantSDNode>(N.getOperand(N.getOperand(0).getValueType() == MVT::Other))->getZExtValue();
1344 if (iid < Intrinsic::num_intrinsics)
1345 llvm_report_error("Cannot yet select: intrinsic %" + Intrinsic::getName((Intrinsic::ID)iid));
1346 else if (const TargetIntrinsicInfo *tii = TM.getIntrinsicInfo())
1347 llvm_report_error(Twine("Cannot yet select: target intrinsic %") +
1351 char SelectionDAGISel::ID = 0;