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 "SelectionDAGBuilder.h"
17 #include "FunctionLoweringInfo.h"
18 #include "llvm/CodeGen/SelectionDAGISel.h"
19 #include "llvm/Analysis/AliasAnalysis.h"
20 #include "llvm/Analysis/DebugInfo.h"
21 #include "llvm/Constants.h"
22 #include "llvm/CallingConv.h"
23 #include "llvm/DerivedTypes.h"
24 #include "llvm/Function.h"
25 #include "llvm/GlobalVariable.h"
26 #include "llvm/InlineAsm.h"
27 #include "llvm/Instructions.h"
28 #include "llvm/Intrinsics.h"
29 #include "llvm/IntrinsicInst.h"
30 #include "llvm/LLVMContext.h"
31 #include "llvm/CodeGen/FastISel.h"
32 #include "llvm/CodeGen/GCStrategy.h"
33 #include "llvm/CodeGen/GCMetadata.h"
34 #include "llvm/CodeGen/MachineFunction.h"
35 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
36 #include "llvm/CodeGen/MachineFrameInfo.h"
37 #include "llvm/CodeGen/MachineInstrBuilder.h"
38 #include "llvm/CodeGen/MachineJumpTableInfo.h"
39 #include "llvm/CodeGen/MachineModuleInfo.h"
40 #include "llvm/CodeGen/MachineRegisterInfo.h"
41 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
42 #include "llvm/CodeGen/SchedulerRegistry.h"
43 #include "llvm/CodeGen/SelectionDAG.h"
44 #include "llvm/CodeGen/DwarfWriter.h"
45 #include "llvm/Target/TargetRegisterInfo.h"
46 #include "llvm/Target/TargetData.h"
47 #include "llvm/Target/TargetFrameInfo.h"
48 #include "llvm/Target/TargetIntrinsicInfo.h"
49 #include "llvm/Target/TargetInstrInfo.h"
50 #include "llvm/Target/TargetLowering.h"
51 #include "llvm/Target/TargetMachine.h"
52 #include "llvm/Target/TargetOptions.h"
53 #include "llvm/Support/Compiler.h"
54 #include "llvm/Support/Debug.h"
55 #include "llvm/Support/ErrorHandling.h"
56 #include "llvm/Support/MathExtras.h"
57 #include "llvm/Support/Timer.h"
58 #include "llvm/Support/raw_ostream.h"
63 EnableFastISelVerbose("fast-isel-verbose", cl::Hidden,
64 cl::desc("Enable verbose messages in the \"fast\" "
65 "instruction selector"));
67 EnableFastISelAbort("fast-isel-abort", cl::Hidden,
68 cl::desc("Enable abort calls when \"fast\" instruction fails"));
70 SchedLiveInCopies("schedule-livein-copies", cl::Hidden,
71 cl::desc("Schedule copies of livein registers"),
76 ViewDAGCombine1("view-dag-combine1-dags", cl::Hidden,
77 cl::desc("Pop up a window to show dags before the first "
80 ViewLegalizeTypesDAGs("view-legalize-types-dags", cl::Hidden,
81 cl::desc("Pop up a window to show dags before legalize types"));
83 ViewLegalizeDAGs("view-legalize-dags", cl::Hidden,
84 cl::desc("Pop up a window to show dags before legalize"));
86 ViewDAGCombine2("view-dag-combine2-dags", cl::Hidden,
87 cl::desc("Pop up a window to show dags before the second "
90 ViewDAGCombineLT("view-dag-combine-lt-dags", cl::Hidden,
91 cl::desc("Pop up a window to show dags before the post legalize types"
92 " dag combine pass"));
94 ViewISelDAGs("view-isel-dags", cl::Hidden,
95 cl::desc("Pop up a window to show isel dags as they are selected"));
97 ViewSchedDAGs("view-sched-dags", cl::Hidden,
98 cl::desc("Pop up a window to show sched dags as they are processed"));
100 ViewSUnitDAGs("view-sunit-dags", cl::Hidden,
101 cl::desc("Pop up a window to show SUnit dags after they are processed"));
103 static const bool ViewDAGCombine1 = false,
104 ViewLegalizeTypesDAGs = false, ViewLegalizeDAGs = false,
105 ViewDAGCombine2 = false,
106 ViewDAGCombineLT = false,
107 ViewISelDAGs = false, ViewSchedDAGs = false,
108 ViewSUnitDAGs = false;
111 //===---------------------------------------------------------------------===//
113 /// RegisterScheduler class - Track the registration of instruction schedulers.
115 //===---------------------------------------------------------------------===//
116 MachinePassRegistry RegisterScheduler::Registry;
118 //===---------------------------------------------------------------------===//
120 /// ISHeuristic command line option for instruction schedulers.
122 //===---------------------------------------------------------------------===//
123 static cl::opt<RegisterScheduler::FunctionPassCtor, false,
124 RegisterPassParser<RegisterScheduler> >
125 ISHeuristic("pre-RA-sched",
126 cl::init(&createDefaultScheduler),
127 cl::desc("Instruction schedulers available (before register"
130 static RegisterScheduler
131 defaultListDAGScheduler("default", "Best scheduler for the target",
132 createDefaultScheduler);
135 //===--------------------------------------------------------------------===//
136 /// createDefaultScheduler - This creates an instruction scheduler appropriate
138 ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
139 CodeGenOpt::Level OptLevel) {
140 const TargetLowering &TLI = IS->getTargetLowering();
142 if (OptLevel == CodeGenOpt::None)
143 return createFastDAGScheduler(IS, OptLevel);
144 if (TLI.getSchedulingPreference() == TargetLowering::SchedulingForLatency)
145 return createTDListDAGScheduler(IS, OptLevel);
146 assert(TLI.getSchedulingPreference() ==
147 TargetLowering::SchedulingForRegPressure && "Unknown sched type!");
148 return createBURRListDAGScheduler(IS, OptLevel);
152 // EmitInstrWithCustomInserter - This method should be implemented by targets
153 // that mark instructions with the 'usesCustomInserter' flag. These
154 // instructions are special in various ways, which require special support to
155 // insert. The specified MachineInstr is created but not inserted into any
156 // basic blocks, and this method is called to expand it into a sequence of
157 // instructions, potentially also creating new basic blocks and control flow.
158 // When new basic blocks are inserted and the edges from MBB to its successors
159 // are modified, the method should insert pairs of <OldSucc, NewSucc> into the
161 MachineBasicBlock *TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
162 MachineBasicBlock *MBB,
163 DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const {
165 dbgs() << "If a target marks an instruction with "
166 "'usesCustomInserter', it must implement "
167 "TargetLowering::EmitInstrWithCustomInserter!";
173 /// EmitLiveInCopy - Emit a copy for a live in physical register. If the
174 /// physical register has only a single copy use, then coalesced the copy
176 static void EmitLiveInCopy(MachineBasicBlock *MBB,
177 MachineBasicBlock::iterator &InsertPos,
178 unsigned VirtReg, unsigned PhysReg,
179 const TargetRegisterClass *RC,
180 DenseMap<MachineInstr*, unsigned> &CopyRegMap,
181 const MachineRegisterInfo &MRI,
182 const TargetRegisterInfo &TRI,
183 const TargetInstrInfo &TII) {
184 unsigned NumUses = 0;
185 MachineInstr *UseMI = NULL;
186 for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg),
187 UE = MRI.use_end(); UI != UE; ++UI) {
193 // If the number of uses is not one, or the use is not a move instruction,
194 // don't coalesce. Also, only coalesce away a virtual register to virtual
196 bool Coalesced = false;
197 unsigned SrcReg, DstReg, SrcSubReg, DstSubReg;
199 TII.isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubReg, DstSubReg) &&
200 TargetRegisterInfo::isVirtualRegister(DstReg)) {
205 // Now find an ideal location to insert the copy.
206 MachineBasicBlock::iterator Pos = InsertPos;
207 while (Pos != MBB->begin()) {
208 MachineInstr *PrevMI = prior(Pos);
209 DenseMap<MachineInstr*, unsigned>::iterator RI = CopyRegMap.find(PrevMI);
210 // copyRegToReg might emit multiple instructions to do a copy.
211 unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second;
212 if (CopyDstReg && !TRI.regsOverlap(CopyDstReg, PhysReg))
213 // This is what the BB looks like right now:
218 // We want to insert "r1025 = mov r1". Inserting this copy below the
219 // move to r1024 makes it impossible for that move to be coalesced.
226 break; // Woot! Found a good location.
230 bool Emitted = TII.copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC);
231 assert(Emitted && "Unable to issue a live-in copy instruction!\n");
234 CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg));
236 if (&*InsertPos == UseMI) ++InsertPos;
241 /// EmitLiveInCopies - If this is the first basic block in the function,
242 /// and if it has live ins that need to be copied into vregs, emit the
243 /// copies into the block.
244 static void EmitLiveInCopies(MachineBasicBlock *EntryMBB,
245 const MachineRegisterInfo &MRI,
246 const TargetRegisterInfo &TRI,
247 const TargetInstrInfo &TII) {
248 if (SchedLiveInCopies) {
249 // Emit the copies at a heuristically-determined location in the block.
250 DenseMap<MachineInstr*, unsigned> CopyRegMap;
251 MachineBasicBlock::iterator InsertPos = EntryMBB->begin();
252 for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(),
253 E = MRI.livein_end(); LI != E; ++LI)
255 const TargetRegisterClass *RC = MRI.getRegClass(LI->second);
256 EmitLiveInCopy(EntryMBB, InsertPos, LI->second, LI->first,
257 RC, CopyRegMap, MRI, TRI, TII);
260 // Emit the copies into the top of the block.
261 for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(),
262 E = MRI.livein_end(); LI != E; ++LI)
264 const TargetRegisterClass *RC = MRI.getRegClass(LI->second);
265 bool Emitted = TII.copyRegToReg(*EntryMBB, EntryMBB->begin(),
266 LI->second, LI->first, RC, RC);
267 assert(Emitted && "Unable to issue a live-in copy instruction!\n");
273 //===----------------------------------------------------------------------===//
274 // SelectionDAGISel code
275 //===----------------------------------------------------------------------===//
277 SelectionDAGISel::SelectionDAGISel(TargetMachine &tm, CodeGenOpt::Level OL) :
278 MachineFunctionPass(&ID), TM(tm), TLI(*tm.getTargetLowering()),
279 FuncInfo(new FunctionLoweringInfo(TLI)),
280 CurDAG(new SelectionDAG(TLI, *FuncInfo)),
281 SDB(new SelectionDAGBuilder(*CurDAG, TLI, *FuncInfo, OL)),
287 SelectionDAGISel::~SelectionDAGISel() {
293 unsigned SelectionDAGISel::MakeReg(EVT VT) {
294 return RegInfo->createVirtualRegister(TLI.getRegClassFor(VT));
297 void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
298 AU.addRequired<AliasAnalysis>();
299 AU.addPreserved<AliasAnalysis>();
300 AU.addRequired<GCModuleInfo>();
301 AU.addPreserved<GCModuleInfo>();
302 AU.addRequired<DwarfWriter>();
303 AU.addPreserved<DwarfWriter>();
304 MachineFunctionPass::getAnalysisUsage(AU);
307 bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
308 Function &Fn = *mf.getFunction();
310 // Do some sanity-checking on the command-line options.
311 assert((!EnableFastISelVerbose || EnableFastISel) &&
312 "-fast-isel-verbose requires -fast-isel");
313 assert((!EnableFastISelAbort || EnableFastISel) &&
314 "-fast-isel-abort requires -fast-isel");
316 // Get alias analysis for load/store combining.
317 AA = &getAnalysis<AliasAnalysis>();
320 const TargetInstrInfo &TII = *TM.getInstrInfo();
321 const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
324 GFI = &getAnalysis<GCModuleInfo>().getFunctionInfo(Fn);
327 RegInfo = &MF->getRegInfo();
328 DEBUG(dbgs() << "\n\n\n=== " << Fn.getName() << "\n");
330 MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
331 DwarfWriter *DW = getAnalysisIfAvailable<DwarfWriter>();
332 CurDAG->init(*MF, MMI, DW);
333 FuncInfo->set(Fn, *MF, EnableFastISel);
336 for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
337 if (InvokeInst *Invoke = dyn_cast<InvokeInst>(I->getTerminator()))
339 FuncInfo->MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
341 SelectAllBasicBlocks(Fn, *MF, MMI, DW, TII);
343 // If the first basic block in the function has live ins that need to be
344 // copied into vregs, emit the copies into the top of the block before
345 // emitting the code for the block.
346 EmitLiveInCopies(MF->begin(), *RegInfo, TRI, TII);
348 // Add function live-ins to entry block live-in set.
349 for (MachineRegisterInfo::livein_iterator I = RegInfo->livein_begin(),
350 E = RegInfo->livein_end(); I != E; ++I)
351 MF->begin()->addLiveIn(I->first);
354 assert(FuncInfo->CatchInfoFound.size() == FuncInfo->CatchInfoLost.size() &&
355 "Not all catch info was assigned to a landing pad!");
363 /// SetDebugLoc - Update MF's and SDB's DebugLocs if debug information is
364 /// attached with this instruction.
365 static void SetDebugLoc(unsigned MDDbgKind, Instruction *I,
366 SelectionDAGBuilder *SDB,
367 FastISel *FastIS, MachineFunction *MF) {
368 if (isa<DbgInfoIntrinsic>(I)) return;
370 if (MDNode *Dbg = I->getMetadata(MDDbgKind)) {
371 DILocation DILoc(Dbg);
372 DebugLoc Loc = ExtractDebugLocation(DILoc, MF->getDebugLocInfo());
374 SDB->setCurDebugLoc(Loc);
377 FastIS->setCurDebugLoc(Loc);
379 // If the function doesn't have a default debug location yet, set
380 // it. This is kind of a hack.
381 if (MF->getDefaultDebugLoc().isUnknown())
382 MF->setDefaultDebugLoc(Loc);
386 /// ResetDebugLoc - Set MF's and SDB's DebugLocs to Unknown.
387 static void ResetDebugLoc(SelectionDAGBuilder *SDB, FastISel *FastIS) {
388 SDB->setCurDebugLoc(DebugLoc::getUnknownLoc());
390 FastIS->setCurDebugLoc(DebugLoc::getUnknownLoc());
393 void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB,
394 BasicBlock::iterator Begin,
395 BasicBlock::iterator End,
397 SDB->setCurrentBasicBlock(BB);
398 unsigned MDDbgKind = LLVMBB->getContext().getMDKindID("dbg");
400 // Lower all of the non-terminator instructions. If a call is emitted
401 // as a tail call, cease emitting nodes for this block.
402 for (BasicBlock::iterator I = Begin; I != End && !SDB->HasTailCall; ++I) {
403 SetDebugLoc(MDDbgKind, I, SDB, 0, MF);
405 if (!isa<TerminatorInst>(I)) {
408 // Set the current debug location back to "unknown" so that it doesn't
409 // spuriously apply to subsequent instructions.
410 ResetDebugLoc(SDB, 0);
414 if (!SDB->HasTailCall) {
415 // Ensure that all instructions which are used outside of their defining
416 // blocks are available as virtual registers. Invoke is handled elsewhere.
417 for (BasicBlock::iterator I = Begin; I != End; ++I)
418 if (!isa<PHINode>(I) && !isa<InvokeInst>(I))
419 SDB->CopyToExportRegsIfNeeded(I);
421 // Handle PHI nodes in successor blocks.
422 if (End == LLVMBB->end()) {
423 HandlePHINodesInSuccessorBlocks(LLVMBB);
425 // Lower the terminator after the copies are emitted.
426 SetDebugLoc(MDDbgKind, LLVMBB->getTerminator(), SDB, 0, MF);
427 SDB->visit(*LLVMBB->getTerminator());
428 ResetDebugLoc(SDB, 0);
432 // Make sure the root of the DAG is up-to-date.
433 CurDAG->setRoot(SDB->getControlRoot());
435 // Final step, emit the lowered DAG as machine code.
437 HadTailCall = SDB->HasTailCall;
441 /// ShrinkDemandedOps - A late transformation pass that shrink expressions
442 /// using TargetLowering::TargetLoweringOpt::ShrinkDemandedOp. It converts
443 /// x+y to (VT)((SmallVT)x+(SmallVT)y) if the casts are free.
444 void SelectionDAGISel::ShrinkDemandedOps() {
445 SmallVector<SDNode*, 128> Worklist;
447 // Add all the dag nodes to the worklist.
448 Worklist.reserve(CurDAG->allnodes_size());
449 for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
450 E = CurDAG->allnodes_end(); I != E; ++I)
451 Worklist.push_back(I);
457 TargetLowering::TargetLoweringOpt TLO(*CurDAG, true);
458 while (!Worklist.empty()) {
459 SDNode *N = Worklist.back();
462 if (N->use_empty() && N != CurDAG->getRoot().getNode()) {
463 CurDAG->DeleteNode(N);
467 // Run ShrinkDemandedOp on scalar binary operations.
468 if (N->getNumValues() == 1 &&
469 N->getValueType(0).isSimple() && N->getValueType(0).isInteger()) {
470 DebugLoc dl = N->getDebugLoc();
471 unsigned BitWidth = N->getValueType(0).getScalarType().getSizeInBits();
472 APInt Demanded = APInt::getAllOnesValue(BitWidth);
473 APInt KnownZero, KnownOne;
474 if (TLI.SimplifyDemandedBits(SDValue(N, 0), Demanded,
475 KnownZero, KnownOne, TLO)) {
477 Worklist.erase(std::remove(Worklist.begin(), Worklist.end(), N),
479 Worklist.push_back(N);
481 // Replace the old value with the new one.
482 DEBUG(errs() << "\nReplacing ";
483 TLO.Old.getNode()->dump(CurDAG);
484 errs() << "\nWith: ";
485 TLO.New.getNode()->dump(CurDAG);
488 Worklist.push_back(TLO.New.getNode());
489 CurDAG->ReplaceAllUsesOfValueWith(TLO.Old, TLO.New);
491 if (TLO.Old.getNode()->use_empty()) {
492 for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands();
494 SDNode *OpNode = TLO.Old.getNode()->getOperand(i).getNode();
495 if (OpNode->hasOneUse()) {
496 Worklist.erase(std::remove(Worklist.begin(), Worklist.end(),
499 Worklist.push_back(TLO.Old.getNode()->getOperand(i).getNode());
503 Worklist.erase(std::remove(Worklist.begin(), Worklist.end(),
506 CurDAG->DeleteNode(TLO.Old.getNode());
513 void SelectionDAGISel::ComputeLiveOutVRegInfo() {
514 SmallPtrSet<SDNode*, 128> VisitedNodes;
515 SmallVector<SDNode*, 128> Worklist;
517 Worklist.push_back(CurDAG->getRoot().getNode());
523 while (!Worklist.empty()) {
524 SDNode *N = Worklist.back();
527 // If we've already seen this node, ignore it.
528 if (!VisitedNodes.insert(N))
531 // Otherwise, add all chain operands to the worklist.
532 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
533 if (N->getOperand(i).getValueType() == MVT::Other)
534 Worklist.push_back(N->getOperand(i).getNode());
536 // If this is a CopyToReg with a vreg dest, process it.
537 if (N->getOpcode() != ISD::CopyToReg)
540 unsigned DestReg = cast<RegisterSDNode>(N->getOperand(1))->getReg();
541 if (!TargetRegisterInfo::isVirtualRegister(DestReg))
544 // Ignore non-scalar or non-integer values.
545 SDValue Src = N->getOperand(2);
546 EVT SrcVT = Src.getValueType();
547 if (!SrcVT.isInteger() || SrcVT.isVector())
550 unsigned NumSignBits = CurDAG->ComputeNumSignBits(Src);
551 Mask = APInt::getAllOnesValue(SrcVT.getSizeInBits());
552 CurDAG->ComputeMaskedBits(Src, Mask, KnownZero, KnownOne);
554 // Only install this information if it tells us something.
555 if (NumSignBits != 1 || KnownZero != 0 || KnownOne != 0) {
556 DestReg -= TargetRegisterInfo::FirstVirtualRegister;
557 if (DestReg >= FuncInfo->LiveOutRegInfo.size())
558 FuncInfo->LiveOutRegInfo.resize(DestReg+1);
559 FunctionLoweringInfo::LiveOutInfo &LOI =
560 FuncInfo->LiveOutRegInfo[DestReg];
561 LOI.NumSignBits = NumSignBits;
562 LOI.KnownOne = KnownOne;
563 LOI.KnownZero = KnownZero;
568 void SelectionDAGISel::CodeGenAndEmitDAG() {
569 std::string GroupName;
570 if (TimePassesIsEnabled)
571 GroupName = "Instruction Selection and Scheduling";
572 std::string BlockName;
573 if (ViewDAGCombine1 || ViewLegalizeTypesDAGs || ViewLegalizeDAGs ||
574 ViewDAGCombine2 || ViewDAGCombineLT || ViewISelDAGs || ViewSchedDAGs ||
576 BlockName = MF->getFunction()->getNameStr() + ":" +
577 BB->getBasicBlock()->getNameStr();
579 DEBUG(dbgs() << "Initial selection DAG:\n");
580 DEBUG(CurDAG->dump());
582 if (ViewDAGCombine1) CurDAG->viewGraph("dag-combine1 input for " + BlockName);
584 // Run the DAG combiner in pre-legalize mode.
585 if (TimePassesIsEnabled) {
586 NamedRegionTimer T("DAG Combining 1", GroupName);
587 CurDAG->Combine(Unrestricted, *AA, OptLevel);
589 CurDAG->Combine(Unrestricted, *AA, OptLevel);
592 DEBUG(dbgs() << "Optimized lowered selection DAG:\n");
593 DEBUG(CurDAG->dump());
595 // Second step, hack on the DAG until it only uses operations and types that
596 // the target supports.
597 if (ViewLegalizeTypesDAGs) CurDAG->viewGraph("legalize-types input for " +
601 if (TimePassesIsEnabled) {
602 NamedRegionTimer T("Type Legalization", GroupName);
603 Changed = CurDAG->LegalizeTypes();
605 Changed = CurDAG->LegalizeTypes();
608 DEBUG(dbgs() << "Type-legalized selection DAG:\n");
609 DEBUG(CurDAG->dump());
612 if (ViewDAGCombineLT)
613 CurDAG->viewGraph("dag-combine-lt input for " + BlockName);
615 // Run the DAG combiner in post-type-legalize mode.
616 if (TimePassesIsEnabled) {
617 NamedRegionTimer T("DAG Combining after legalize types", GroupName);
618 CurDAG->Combine(NoIllegalTypes, *AA, OptLevel);
620 CurDAG->Combine(NoIllegalTypes, *AA, OptLevel);
623 DEBUG(dbgs() << "Optimized type-legalized selection DAG:\n");
624 DEBUG(CurDAG->dump());
627 if (TimePassesIsEnabled) {
628 NamedRegionTimer T("Vector Legalization", GroupName);
629 Changed = CurDAG->LegalizeVectors();
631 Changed = CurDAG->LegalizeVectors();
635 if (TimePassesIsEnabled) {
636 NamedRegionTimer T("Type Legalization 2", GroupName);
637 CurDAG->LegalizeTypes();
639 CurDAG->LegalizeTypes();
642 if (ViewDAGCombineLT)
643 CurDAG->viewGraph("dag-combine-lv input for " + BlockName);
645 // Run the DAG combiner in post-type-legalize mode.
646 if (TimePassesIsEnabled) {
647 NamedRegionTimer T("DAG Combining after legalize vectors", GroupName);
648 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
650 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
653 DEBUG(dbgs() << "Optimized vector-legalized selection DAG:\n");
654 DEBUG(CurDAG->dump());
657 if (ViewLegalizeDAGs) CurDAG->viewGraph("legalize input for " + BlockName);
659 if (TimePassesIsEnabled) {
660 NamedRegionTimer T("DAG Legalization", GroupName);
661 CurDAG->Legalize(OptLevel);
663 CurDAG->Legalize(OptLevel);
666 DEBUG(dbgs() << "Legalized selection DAG:\n");
667 DEBUG(CurDAG->dump());
669 if (ViewDAGCombine2) CurDAG->viewGraph("dag-combine2 input for " + BlockName);
671 // Run the DAG combiner in post-legalize mode.
672 if (TimePassesIsEnabled) {
673 NamedRegionTimer T("DAG Combining 2", GroupName);
674 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
676 CurDAG->Combine(NoIllegalOperations, *AA, OptLevel);
679 DEBUG(dbgs() << "Optimized legalized selection DAG:\n");
680 DEBUG(CurDAG->dump());
682 if (ViewISelDAGs) CurDAG->viewGraph("isel input for " + BlockName);
684 if (OptLevel != CodeGenOpt::None) {
686 ComputeLiveOutVRegInfo();
689 // Third, instruction select all of the operations to machine code, adding the
690 // code to the MachineBasicBlock.
691 if (TimePassesIsEnabled) {
692 NamedRegionTimer T("Instruction Selection", GroupName);
698 DEBUG(dbgs() << "Selected selection DAG:\n");
699 DEBUG(CurDAG->dump());
701 if (ViewSchedDAGs) CurDAG->viewGraph("scheduler input for " + BlockName);
703 // Schedule machine code.
704 ScheduleDAGSDNodes *Scheduler = CreateScheduler();
705 if (TimePassesIsEnabled) {
706 NamedRegionTimer T("Instruction Scheduling", GroupName);
707 Scheduler->Run(CurDAG, BB, BB->end());
709 Scheduler->Run(CurDAG, BB, BB->end());
712 if (ViewSUnitDAGs) Scheduler->viewGraph();
714 // Emit machine code to BB. This can change 'BB' to the last block being
716 if (TimePassesIsEnabled) {
717 NamedRegionTimer T("Instruction Creation", GroupName);
718 BB = Scheduler->EmitSchedule(&SDB->EdgeMapping);
720 BB = Scheduler->EmitSchedule(&SDB->EdgeMapping);
723 // Free the scheduler state.
724 if (TimePassesIsEnabled) {
725 NamedRegionTimer T("Instruction Scheduling Cleanup", GroupName);
731 DEBUG(dbgs() << "Selected machine code:\n");
735 void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn,
737 MachineModuleInfo *MMI,
739 const TargetInstrInfo &TII) {
740 // Initialize the Fast-ISel state, if needed.
741 FastISel *FastIS = 0;
743 FastIS = TLI.createFastISel(MF, MMI, DW,
746 FuncInfo->StaticAllocaMap
748 , FuncInfo->CatchInfoLost
752 unsigned MDDbgKind = Fn.getContext().getMDKindID("dbg");
754 // Iterate over all basic blocks in the function.
755 for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
756 BasicBlock *LLVMBB = &*I;
757 BB = FuncInfo->MBBMap[LLVMBB];
759 BasicBlock::iterator const Begin = LLVMBB->begin();
760 BasicBlock::iterator const End = LLVMBB->end();
761 BasicBlock::iterator BI = Begin;
763 // Lower any arguments needed in this block if this is the entry block.
764 bool SuppressFastISel = false;
765 if (LLVMBB == &Fn.getEntryBlock()) {
766 LowerArguments(LLVMBB);
768 // If any of the arguments has the byval attribute, forgo
769 // fast-isel in the entry block.
772 for (Function::arg_iterator I = Fn.arg_begin(), E = Fn.arg_end();
774 if (Fn.paramHasAttr(j, Attribute::ByVal)) {
775 if (EnableFastISelVerbose || EnableFastISelAbort)
776 dbgs() << "FastISel skips entry block due to byval argument\n";
777 SuppressFastISel = true;
783 if (MMI && BB->isLandingPad()) {
784 // Add a label to mark the beginning of the landing pad. Deletion of the
785 // landing pad can thus be detected via the MachineModuleInfo.
786 unsigned LabelID = MMI->addLandingPad(BB);
788 const TargetInstrDesc &II = TII.get(TargetInstrInfo::EH_LABEL);
789 BuildMI(BB, SDB->getCurDebugLoc(), II).addImm(LabelID);
791 // Mark exception register as live in.
792 unsigned Reg = TLI.getExceptionAddressRegister();
793 if (Reg) BB->addLiveIn(Reg);
795 // Mark exception selector register as live in.
796 Reg = TLI.getExceptionSelectorRegister();
797 if (Reg) BB->addLiveIn(Reg);
799 // FIXME: Hack around an exception handling flaw (PR1508): the personality
800 // function and list of typeids logically belong to the invoke (or, if you
801 // like, the basic block containing the invoke), and need to be associated
802 // with it in the dwarf exception handling tables. Currently however the
803 // information is provided by an intrinsic (eh.selector) that can be moved
804 // to unexpected places by the optimizers: if the unwind edge is critical,
805 // then breaking it can result in the intrinsics being in the successor of
806 // the landing pad, not the landing pad itself. This results in exceptions
807 // not being caught because no typeids are associated with the invoke.
808 // This may not be the only way things can go wrong, but it is the only way
809 // we try to work around for the moment.
810 BranchInst *Br = dyn_cast<BranchInst>(LLVMBB->getTerminator());
812 if (Br && Br->isUnconditional()) { // Critical edge?
813 BasicBlock::iterator I, E;
814 for (I = LLVMBB->begin(), E = --LLVMBB->end(); I != E; ++I)
815 if (isa<EHSelectorInst>(I))
819 // No catch info found - try to extract some from the successor.
820 CopyCatchInfo(Br->getSuccessor(0), LLVMBB, MMI, *FuncInfo);
824 // Before doing SelectionDAG ISel, see if FastISel has been requested.
825 if (FastIS && !SuppressFastISel) {
826 // Emit code for any incoming arguments. This must happen before
827 // beginning FastISel on the entry block.
828 if (LLVMBB == &Fn.getEntryBlock()) {
829 CurDAG->setRoot(SDB->getControlRoot());
833 FastIS->startNewBlock(BB);
834 // Do FastISel on as many instructions as possible.
835 for (; BI != End; ++BI) {
836 // Just before the terminator instruction, insert instructions to
837 // feed PHI nodes in successor blocks.
838 if (isa<TerminatorInst>(BI))
839 if (!HandlePHINodesInSuccessorBlocksFast(LLVMBB, FastIS)) {
840 ResetDebugLoc(SDB, FastIS);
841 if (EnableFastISelVerbose || EnableFastISelAbort) {
842 dbgs() << "FastISel miss: ";
845 assert(!EnableFastISelAbort &&
846 "FastISel didn't handle a PHI in a successor");
850 SetDebugLoc(MDDbgKind, BI, SDB, FastIS, &MF);
852 // First try normal tablegen-generated "fast" selection.
853 if (FastIS->SelectInstruction(BI)) {
854 ResetDebugLoc(SDB, FastIS);
858 // Clear out the debug location so that it doesn't carry over to
859 // unrelated instructions.
860 ResetDebugLoc(SDB, FastIS);
862 // Then handle certain instructions as single-LLVM-Instruction blocks.
863 if (isa<CallInst>(BI)) {
864 if (EnableFastISelVerbose || EnableFastISelAbort) {
865 dbgs() << "FastISel missed call: ";
869 if (!BI->getType()->isVoidTy()) {
870 unsigned &R = FuncInfo->ValueMap[BI];
872 R = FuncInfo->CreateRegForValue(BI);
875 bool HadTailCall = false;
876 SelectBasicBlock(LLVMBB, BI, llvm::next(BI), HadTailCall);
878 // If the call was emitted as a tail call, we're done with the block.
884 // If the instruction was codegen'd with multiple blocks,
885 // inform the FastISel object where to resume inserting.
886 FastIS->setCurrentBlock(BB);
890 // Otherwise, give up on FastISel for the rest of the block.
891 // For now, be a little lenient about non-branch terminators.
892 if (!isa<TerminatorInst>(BI) || isa<BranchInst>(BI)) {
893 if (EnableFastISelVerbose || EnableFastISelAbort) {
894 dbgs() << "FastISel miss: ";
897 if (EnableFastISelAbort)
898 // The "fast" selector couldn't handle something and bailed.
899 // For the purpose of debugging, just abort.
900 llvm_unreachable("FastISel didn't select the entire block");
906 // Run SelectionDAG instruction selection on the remainder of the block
907 // not handled by FastISel. If FastISel is not run, this is the entire
911 SelectBasicBlock(LLVMBB, BI, End, HadTailCall);
921 SelectionDAGISel::FinishBasicBlock() {
923 DEBUG(dbgs() << "Target-post-processed machine code:\n");
926 DEBUG(dbgs() << "Total amount of phi nodes to update: "
927 << SDB->PHINodesToUpdate.size() << "\n");
928 DEBUG(for (unsigned i = 0, e = SDB->PHINodesToUpdate.size(); i != e; ++i)
929 dbgs() << "Node " << i << " : ("
930 << SDB->PHINodesToUpdate[i].first
931 << ", " << SDB->PHINodesToUpdate[i].second << ")\n");
933 // Next, now that we know what the last MBB the LLVM BB expanded is, update
934 // PHI nodes in successors.
935 if (SDB->SwitchCases.empty() &&
936 SDB->JTCases.empty() &&
937 SDB->BitTestCases.empty()) {
938 for (unsigned i = 0, e = SDB->PHINodesToUpdate.size(); i != e; ++i) {
939 MachineInstr *PHI = SDB->PHINodesToUpdate[i].first;
940 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
941 "This is not a machine PHI node that we are updating!");
942 PHI->addOperand(MachineOperand::CreateReg(SDB->PHINodesToUpdate[i].second,
944 PHI->addOperand(MachineOperand::CreateMBB(BB));
946 SDB->PHINodesToUpdate.clear();
950 for (unsigned i = 0, e = SDB->BitTestCases.size(); i != e; ++i) {
951 // Lower header first, if it wasn't already lowered
952 if (!SDB->BitTestCases[i].Emitted) {
953 // Set the current basic block to the mbb we wish to insert the code into
954 BB = SDB->BitTestCases[i].Parent;
955 SDB->setCurrentBasicBlock(BB);
957 SDB->visitBitTestHeader(SDB->BitTestCases[i]);
958 CurDAG->setRoot(SDB->getRoot());
963 for (unsigned j = 0, ej = SDB->BitTestCases[i].Cases.size(); j != ej; ++j) {
964 // Set the current basic block to the mbb we wish to insert the code into
965 BB = SDB->BitTestCases[i].Cases[j].ThisBB;
966 SDB->setCurrentBasicBlock(BB);
969 SDB->visitBitTestCase(SDB->BitTestCases[i].Cases[j+1].ThisBB,
970 SDB->BitTestCases[i].Reg,
971 SDB->BitTestCases[i].Cases[j]);
973 SDB->visitBitTestCase(SDB->BitTestCases[i].Default,
974 SDB->BitTestCases[i].Reg,
975 SDB->BitTestCases[i].Cases[j]);
978 CurDAG->setRoot(SDB->getRoot());
984 for (unsigned pi = 0, pe = SDB->PHINodesToUpdate.size(); pi != pe; ++pi) {
985 MachineInstr *PHI = SDB->PHINodesToUpdate[pi].first;
986 MachineBasicBlock *PHIBB = PHI->getParent();
987 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
988 "This is not a machine PHI node that we are updating!");
989 // This is "default" BB. We have two jumps to it. From "header" BB and
990 // from last "case" BB.
991 if (PHIBB == SDB->BitTestCases[i].Default) {
992 PHI->addOperand(MachineOperand::CreateReg(SDB->PHINodesToUpdate[pi].second,
994 PHI->addOperand(MachineOperand::CreateMBB(SDB->BitTestCases[i].Parent));
995 PHI->addOperand(MachineOperand::CreateReg(SDB->PHINodesToUpdate[pi].second,
997 PHI->addOperand(MachineOperand::CreateMBB(SDB->BitTestCases[i].Cases.
1000 // One of "cases" BB.
1001 for (unsigned j = 0, ej = SDB->BitTestCases[i].Cases.size();
1003 MachineBasicBlock* cBB = SDB->BitTestCases[i].Cases[j].ThisBB;
1004 if (cBB->succ_end() !=
1005 std::find(cBB->succ_begin(),cBB->succ_end(), PHIBB)) {
1006 PHI->addOperand(MachineOperand::CreateReg(SDB->PHINodesToUpdate[pi].second,
1008 PHI->addOperand(MachineOperand::CreateMBB(cBB));
1013 SDB->BitTestCases.clear();
1015 // If the JumpTable record is filled in, then we need to emit a jump table.
1016 // Updating the PHI nodes is tricky in this case, since we need to determine
1017 // whether the PHI is a successor of the range check MBB or the jump table MBB
1018 for (unsigned i = 0, e = SDB->JTCases.size(); i != e; ++i) {
1019 // Lower header first, if it wasn't already lowered
1020 if (!SDB->JTCases[i].first.Emitted) {
1021 // Set the current basic block to the mbb we wish to insert the code into
1022 BB = SDB->JTCases[i].first.HeaderBB;
1023 SDB->setCurrentBasicBlock(BB);
1025 SDB->visitJumpTableHeader(SDB->JTCases[i].second, SDB->JTCases[i].first);
1026 CurDAG->setRoot(SDB->getRoot());
1027 CodeGenAndEmitDAG();
1031 // Set the current basic block to the mbb we wish to insert the code into
1032 BB = SDB->JTCases[i].second.MBB;
1033 SDB->setCurrentBasicBlock(BB);
1035 SDB->visitJumpTable(SDB->JTCases[i].second);
1036 CurDAG->setRoot(SDB->getRoot());
1037 CodeGenAndEmitDAG();
1041 for (unsigned pi = 0, pe = SDB->PHINodesToUpdate.size(); pi != pe; ++pi) {
1042 MachineInstr *PHI = SDB->PHINodesToUpdate[pi].first;
1043 MachineBasicBlock *PHIBB = PHI->getParent();
1044 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
1045 "This is not a machine PHI node that we are updating!");
1046 // "default" BB. We can go there only from header BB.
1047 if (PHIBB == SDB->JTCases[i].second.Default) {
1049 (MachineOperand::CreateReg(SDB->PHINodesToUpdate[pi].second, false));
1051 (MachineOperand::CreateMBB(SDB->JTCases[i].first.HeaderBB));
1053 // JT BB. Just iterate over successors here
1054 if (BB->succ_end() != std::find(BB->succ_begin(),BB->succ_end(), PHIBB)) {
1056 (MachineOperand::CreateReg(SDB->PHINodesToUpdate[pi].second, false));
1057 PHI->addOperand(MachineOperand::CreateMBB(BB));
1061 SDB->JTCases.clear();
1063 // If the switch block involved a branch to one of the actual successors, we
1064 // need to update PHI nodes in that block.
1065 for (unsigned i = 0, e = SDB->PHINodesToUpdate.size(); i != e; ++i) {
1066 MachineInstr *PHI = SDB->PHINodesToUpdate[i].first;
1067 assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
1068 "This is not a machine PHI node that we are updating!");
1069 if (BB->isSuccessor(PHI->getParent())) {
1070 PHI->addOperand(MachineOperand::CreateReg(SDB->PHINodesToUpdate[i].second,
1072 PHI->addOperand(MachineOperand::CreateMBB(BB));
1076 // If we generated any switch lowering information, build and codegen any
1077 // additional DAGs necessary.
1078 for (unsigned i = 0, e = SDB->SwitchCases.size(); i != e; ++i) {
1079 // Set the current basic block to the mbb we wish to insert the code into
1080 MachineBasicBlock *ThisBB = BB = SDB->SwitchCases[i].ThisBB;
1081 SDB->setCurrentBasicBlock(BB);
1084 SDB->visitSwitchCase(SDB->SwitchCases[i]);
1085 CurDAG->setRoot(SDB->getRoot());
1086 CodeGenAndEmitDAG();
1088 // Handle any PHI nodes in successors of this chunk, as if we were coming
1089 // from the original BB before switch expansion. Note that PHI nodes can
1090 // occur multiple times in PHINodesToUpdate. We have to be very careful to
1091 // handle them the right number of times.
1092 while ((BB = SDB->SwitchCases[i].TrueBB)) { // Handle LHS and RHS.
1093 // If new BB's are created during scheduling, the edges may have been
1094 // updated. That is, the edge from ThisBB to BB may have been split and
1095 // BB's predecessor is now another block.
1096 DenseMap<MachineBasicBlock*, MachineBasicBlock*>::iterator EI =
1097 SDB->EdgeMapping.find(BB);
1098 if (EI != SDB->EdgeMapping.end())
1099 ThisBB = EI->second;
1100 for (MachineBasicBlock::iterator Phi = BB->begin();
1101 Phi != BB->end() && Phi->getOpcode() == TargetInstrInfo::PHI; ++Phi){
1102 // This value for this PHI node is recorded in PHINodesToUpdate, get it.
1103 for (unsigned pn = 0; ; ++pn) {
1104 assert(pn != SDB->PHINodesToUpdate.size() &&
1105 "Didn't find PHI entry!");
1106 if (SDB->PHINodesToUpdate[pn].first == Phi) {
1107 Phi->addOperand(MachineOperand::CreateReg(SDB->PHINodesToUpdate[pn].
1109 Phi->addOperand(MachineOperand::CreateMBB(ThisBB));
1115 // Don't process RHS if same block as LHS.
1116 if (BB == SDB->SwitchCases[i].FalseBB)
1117 SDB->SwitchCases[i].FalseBB = 0;
1119 // If we haven't handled the RHS, do so now. Otherwise, we're done.
1120 SDB->SwitchCases[i].TrueBB = SDB->SwitchCases[i].FalseBB;
1121 SDB->SwitchCases[i].FalseBB = 0;
1123 assert(SDB->SwitchCases[i].TrueBB == 0 && SDB->SwitchCases[i].FalseBB == 0);
1126 SDB->SwitchCases.clear();
1128 SDB->PHINodesToUpdate.clear();
1132 /// Create the scheduler. If a specific scheduler was specified
1133 /// via the SchedulerRegistry, use it, otherwise select the
1134 /// one preferred by the target.
1136 ScheduleDAGSDNodes *SelectionDAGISel::CreateScheduler() {
1137 RegisterScheduler::FunctionPassCtor Ctor = RegisterScheduler::getDefault();
1141 RegisterScheduler::setDefault(Ctor);
1144 return Ctor(this, OptLevel);
1147 ScheduleHazardRecognizer *SelectionDAGISel::CreateTargetHazardRecognizer() {
1148 return new ScheduleHazardRecognizer();
1151 //===----------------------------------------------------------------------===//
1152 // Helper functions used by the generated instruction selector.
1153 //===----------------------------------------------------------------------===//
1154 // Calls to these methods are generated by tblgen.
1156 /// CheckAndMask - The isel is trying to match something like (and X, 255). If
1157 /// the dag combiner simplified the 255, we still want to match. RHS is the
1158 /// actual value in the DAG on the RHS of an AND, and DesiredMaskS is the value
1159 /// specified in the .td file (e.g. 255).
1160 bool SelectionDAGISel::CheckAndMask(SDValue LHS, ConstantSDNode *RHS,
1161 int64_t DesiredMaskS) const {
1162 const APInt &ActualMask = RHS->getAPIntValue();
1163 const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS);
1165 // If the actual mask exactly matches, success!
1166 if (ActualMask == DesiredMask)
1169 // If the actual AND mask is allowing unallowed bits, this doesn't match.
1170 if (ActualMask.intersects(~DesiredMask))
1173 // Otherwise, the DAG Combiner may have proven that the value coming in is
1174 // either already zero or is not demanded. Check for known zero input bits.
1175 APInt NeededMask = DesiredMask & ~ActualMask;
1176 if (CurDAG->MaskedValueIsZero(LHS, NeededMask))
1179 // TODO: check to see if missing bits are just not demanded.
1181 // Otherwise, this pattern doesn't match.
1185 /// CheckOrMask - The isel is trying to match something like (or X, 255). If
1186 /// the dag combiner simplified the 255, we still want to match. RHS is the
1187 /// actual value in the DAG on the RHS of an OR, and DesiredMaskS is the value
1188 /// specified in the .td file (e.g. 255).
1189 bool SelectionDAGISel::CheckOrMask(SDValue LHS, ConstantSDNode *RHS,
1190 int64_t DesiredMaskS) const {
1191 const APInt &ActualMask = RHS->getAPIntValue();
1192 const APInt &DesiredMask = APInt(LHS.getValueSizeInBits(), DesiredMaskS);
1194 // If the actual mask exactly matches, success!
1195 if (ActualMask == DesiredMask)
1198 // If the actual AND mask is allowing unallowed bits, this doesn't match.
1199 if (ActualMask.intersects(~DesiredMask))
1202 // Otherwise, the DAG Combiner may have proven that the value coming in is
1203 // either already zero or is not demanded. Check for known zero input bits.
1204 APInt NeededMask = DesiredMask & ~ActualMask;
1206 APInt KnownZero, KnownOne;
1207 CurDAG->ComputeMaskedBits(LHS, NeededMask, KnownZero, KnownOne);
1209 // If all the missing bits in the or are already known to be set, match!
1210 if ((NeededMask & KnownOne) == NeededMask)
1213 // TODO: check to see if missing bits are just not demanded.
1215 // Otherwise, this pattern doesn't match.
1220 /// SelectInlineAsmMemoryOperands - Calls to this are automatically generated
1221 /// by tblgen. Others should not call it.
1222 void SelectionDAGISel::
1223 SelectInlineAsmMemoryOperands(std::vector<SDValue> &Ops) {
1224 std::vector<SDValue> InOps;
1225 std::swap(InOps, Ops);
1227 Ops.push_back(InOps[0]); // input chain.
1228 Ops.push_back(InOps[1]); // input asm string.
1230 unsigned i = 2, e = InOps.size();
1231 if (InOps[e-1].getValueType() == MVT::Flag)
1232 --e; // Don't process a flag operand if it is here.
1235 unsigned Flags = cast<ConstantSDNode>(InOps[i])->getZExtValue();
1236 if ((Flags & 7) != 4 /*MEM*/) {
1237 // Just skip over this operand, copying the operands verbatim.
1238 Ops.insert(Ops.end(), InOps.begin()+i,
1239 InOps.begin()+i+InlineAsm::getNumOperandRegisters(Flags) + 1);
1240 i += InlineAsm::getNumOperandRegisters(Flags) + 1;
1242 assert(InlineAsm::getNumOperandRegisters(Flags) == 1 &&
1243 "Memory operand with multiple values?");
1244 // Otherwise, this is a memory operand. Ask the target to select it.
1245 std::vector<SDValue> SelOps;
1246 if (SelectInlineAsmMemoryOperand(InOps[i+1], 'm', SelOps)) {
1247 llvm_report_error("Could not match memory address. Inline asm"
1251 // Add this to the output node.
1252 Ops.push_back(CurDAG->getTargetConstant(4/*MEM*/ | (SelOps.size()<< 3),
1254 Ops.insert(Ops.end(), SelOps.begin(), SelOps.end());
1259 // Add the flag input back if present.
1260 if (e != InOps.size())
1261 Ops.push_back(InOps.back());
1264 /// findFlagUse - Return use of EVT::Flag value produced by the specified
1267 static SDNode *findFlagUse(SDNode *N) {
1268 unsigned FlagResNo = N->getNumValues()-1;
1269 for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) {
1270 SDUse &Use = I.getUse();
1271 if (Use.getResNo() == FlagResNo)
1272 return Use.getUser();
1277 /// findNonImmUse - Return true if "Use" is a non-immediate use of "Def".
1278 /// This function recursively traverses up the operand chain, ignoring
1280 static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse,
1282 SmallPtrSet<SDNode*, 16> &Visited) {
1283 if (Use->getNodeId() < Def->getNodeId() ||
1284 !Visited.insert(Use))
1287 for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) {
1288 SDNode *N = Use->getOperand(i).getNode();
1290 if (Use == ImmedUse || Use == Root)
1291 continue; // We are not looking for immediate use.
1296 // Traverse up the operand chain.
1297 if (findNonImmUse(N, Def, ImmedUse, Root, Visited))
1303 /// isNonImmUse - Start searching from Root up the DAG to check is Def can
1304 /// be reached. Return true if that's the case. However, ignore direct uses
1305 /// by ImmedUse (which would be U in the example illustrated in
1306 /// IsLegalAndProfitableToFold) and by Root (which can happen in the store
1308 /// FIXME: to be really generic, we should allow direct use by any node
1309 /// that is being folded. But realisticly since we only fold loads which
1310 /// have one non-chain use, we only need to watch out for load/op/store
1311 /// and load/op/cmp case where the root (store / cmp) may reach the load via
1312 /// its chain operand.
1313 static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) {
1314 SmallPtrSet<SDNode*, 16> Visited;
1315 return findNonImmUse(Root, Def, ImmedUse, Root, Visited);
1318 /// IsLegalAndProfitableToFold - Returns true if the specific operand node N of
1319 /// U can be folded during instruction selection that starts at Root and
1320 /// folding N is profitable.
1321 bool SelectionDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U,
1322 SDNode *Root) const {
1323 if (OptLevel == CodeGenOpt::None) return false;
1325 // If Root use can somehow reach N through a path that that doesn't contain
1326 // U then folding N would create a cycle. e.g. In the following
1327 // diagram, Root can reach N through X. If N is folded into into Root, then
1328 // X is both a predecessor and a successor of U.
1339 // * indicates nodes to be folded together.
1341 // If Root produces a flag, then it gets (even more) interesting. Since it
1342 // will be "glued" together with its flag use in the scheduler, we need to
1343 // check if it might reach N.
1362 // If FU (flag use) indirectly reaches N (the load), and Root folds N
1363 // (call it Fold), then X is a predecessor of FU and a successor of
1364 // Fold. But since Fold and FU are flagged together, this will create
1365 // a cycle in the scheduling graph.
1367 EVT VT = Root->getValueType(Root->getNumValues()-1);
1368 while (VT == MVT::Flag) {
1369 SDNode *FU = findFlagUse(Root);
1373 VT = Root->getValueType(Root->getNumValues()-1);
1376 return !isNonImmUse(Root, N, U);
1379 SDNode *SelectionDAGISel::Select_INLINEASM(SDNode *N) {
1380 std::vector<SDValue> Ops(N->op_begin(), N->op_end());
1381 SelectInlineAsmMemoryOperands(Ops);
1383 std::vector<EVT> VTs;
1384 VTs.push_back(MVT::Other);
1385 VTs.push_back(MVT::Flag);
1386 SDValue New = CurDAG->getNode(ISD::INLINEASM, N->getDebugLoc(),
1387 VTs, &Ops[0], Ops.size());
1388 return New.getNode();
1391 SDNode *SelectionDAGISel::Select_UNDEF(SDNode *N) {
1392 return CurDAG->SelectNodeTo(N, TargetInstrInfo::IMPLICIT_DEF,
1393 N->getValueType(0));
1396 SDNode *SelectionDAGISel::Select_EH_LABEL(SDNode *N) {
1397 SDValue Chain = N->getOperand(0);
1398 unsigned C = cast<LabelSDNode>(N)->getLabelID();
1399 SDValue Tmp = CurDAG->getTargetConstant(C, MVT::i32);
1400 return CurDAG->SelectNodeTo(N, TargetInstrInfo::EH_LABEL,
1401 MVT::Other, Tmp, Chain);
1404 void SelectionDAGISel::CannotYetSelect(SDNode *N) {
1406 raw_string_ostream Msg(msg);
1407 Msg << "Cannot yet select: ";
1408 N->print(Msg, CurDAG);
1409 llvm_report_error(Msg.str());
1412 void SelectionDAGISel::CannotYetSelectIntrinsic(SDNode *N) {
1413 dbgs() << "Cannot yet select: ";
1415 cast<ConstantSDNode>(N->getOperand(N->getOperand(0).getValueType() == MVT::Other))->getZExtValue();
1416 if (iid < Intrinsic::num_intrinsics)
1417 llvm_report_error("Cannot yet select: intrinsic %" + Intrinsic::getName((Intrinsic::ID)iid));
1418 else if (const TargetIntrinsicInfo *tii = TM.getIntrinsicInfo())
1419 llvm_report_error(Twine("Cannot yet select: target intrinsic %") +
1423 char SelectionDAGISel::ID = 0;