X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FCodeGen%2FMachineBasicBlock.cpp;h=354bd3ef3e8b061ddfac0a420114161dc7eed682;hp=a968ab9514611b417f247fc3cf4ce0f2fbba68a5;hb=70477058aa03c697a654b708e41da95870358139;hpb=4988c1d8c6be046424eb8c6e4644d882c0c4d1f8 diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index a968ab95146..354bd3ef3e8 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -28,7 +28,6 @@ #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/Support/Debug.h" -#include "llvm/Support/Format.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" @@ -39,8 +38,8 @@ using namespace llvm; #define DEBUG_TYPE "codegen" -MachineBasicBlock::MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb) - : BB(bb), Number(-1), xParent(&mf) { +MachineBasicBlock::MachineBasicBlock(MachineFunction &MF, const BasicBlock *B) + : BB(B), Number(-1), xParent(&MF) { Insts.Parent = this; } @@ -53,6 +52,7 @@ MCSymbol *MachineBasicBlock::getSymbol() const { const MachineFunction *MF = getParent(); MCContext &Ctx = MF->getContext(); const char *Prefix = Ctx.getAsmInfo()->getPrivateLabelPrefix(); + assert(getNumber() >= 0 && "cannot get label for unreachable MBB"); CachedMCSymbol = Ctx.getOrCreateSymbol(Twine(Prefix) + "BB" + Twine(MF->getFunctionNumber()) + "_" + Twine(getNumber())); @@ -117,19 +117,19 @@ void ilist_traits::removeNodeFromList(MachineInstr *N) { /// When moving a range of instructions from one MBB list to another, we need to /// update the parent pointers and the use/def lists. void ilist_traits:: -transferNodesFromList(ilist_traits &fromList, - ilist_iterator first, - ilist_iterator last) { - assert(Parent->getParent() == fromList.Parent->getParent() && +transferNodesFromList(ilist_traits &FromList, + ilist_iterator First, + ilist_iterator Last) { + assert(Parent->getParent() == FromList.Parent->getParent() && "MachineInstr parent mismatch!"); // Splice within the same MBB -> no change. - if (Parent == fromList.Parent) return; + if (Parent == FromList.Parent) return; // If splicing between two blocks within the same function, just update the // parent pointers. - for (; first != last; ++first) - first->setParent(Parent); + for (; First != Last; ++First) + First->setParent(Parent); } void ilist_traits::deleteNode(MachineInstr* MI) { @@ -208,6 +208,13 @@ const MachineBasicBlock *MachineBasicBlock::getLandingPadSuccessor() const { return nullptr; } +bool MachineBasicBlock::hasEHPadSuccessor() const { + for (const_succ_iterator I = succ_begin(), E = succ_end(); I != E; ++I) + if ((*I)->isEHPad()) + return true; + return false; +} + #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) void MachineBasicBlock::dump() const { print(dbgs()); @@ -281,7 +288,7 @@ void MachineBasicBlock::print(raw_ostream &OS, ModuleSlotTracker &MST, for (const auto &LI : make_range(livein_begin(), livein_end())) { OS << ' ' << PrintReg(LI.PhysReg, TRI); if (LI.LaneMask != ~0u) - OS << format(":%08X", LI.LaneMask); + OS << ':' << PrintLaneMask(LI.LaneMask); } OS << '\n'; } @@ -296,8 +303,8 @@ void MachineBasicBlock::print(raw_ostream &OS, ModuleSlotTracker &MST, for (const_instr_iterator I = instr_begin(); I != instr_end(); ++I) { if (Indexes) { - if (Indexes->hasIndex(I)) - OS << Indexes->getInstructionIndex(I); + if (Indexes->hasIndex(&*I)) + OS << Indexes->getInstructionIndex(&*I); OS << '\t'; } OS << '\t'; @@ -324,7 +331,7 @@ void MachineBasicBlock::printAsOperand(raw_ostream &OS, OS << "BB#" << getNumber(); } -void MachineBasicBlock::removeLiveIn(MCPhysReg Reg, unsigned LaneMask) { +void MachineBasicBlock::removeLiveIn(MCPhysReg Reg, LaneBitmask LaneMask) { LiveInVector::iterator I = std::find_if( LiveIns.begin(), LiveIns.end(), [Reg] (const RegisterMaskPair &LI) { return LI.PhysReg == Reg; }); @@ -336,7 +343,7 @@ void MachineBasicBlock::removeLiveIn(MCPhysReg Reg, unsigned LaneMask) { LiveIns.erase(I); } -bool MachineBasicBlock::isLiveIn(MCPhysReg Reg, unsigned LaneMask) const { +bool MachineBasicBlock::isLiveIn(MCPhysReg Reg, LaneBitmask LaneMask) const { livein_iterator I = std::find_if( LiveIns.begin(), LiveIns.end(), [Reg] (const RegisterMaskPair &LI) { return LI.PhysReg == Reg; }); @@ -354,7 +361,7 @@ void MachineBasicBlock::sortUniqueLiveIns() { LiveInVector::iterator Out = LiveIns.begin(); for (; I != LiveIns.end(); ++Out, I = J) { unsigned PhysReg = I->PhysReg; - unsigned LaneMask = I->LaneMask; + LaneBitmask LaneMask = I->LaneMask; for (J = std::next(I); J != LiveIns.end() && J->PhysReg == PhysReg; ++J) LaneMask |= J->LaneMask; Out->PhysReg = PhysReg; @@ -396,12 +403,11 @@ MachineBasicBlock::addLiveIn(MCPhysReg PhysReg, const TargetRegisterClass *RC) { } void MachineBasicBlock::moveBefore(MachineBasicBlock *NewAfter) { - getParent()->splice(NewAfter, this); + getParent()->splice(NewAfter->getIterator(), getIterator()); } void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) { - MachineFunction::iterator BBI = NewBefore; - getParent()->splice(++BBI, this); + getParent()->splice(++NewBefore->getIterator(), getIterator()); } void MachineBasicBlock::updateTerminator() { @@ -411,7 +417,7 @@ void MachineBasicBlock::updateTerminator() { MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector Cond; - DebugLoc dl; // FIXME: this is nowhere + DebugLoc DL; // FIXME: this is nowhere bool B = TII->AnalyzeBranch(*this, TBB, FBB, Cond); (void) B; assert(!B && "UpdateTerminators requires analyzable predecessors!"); @@ -440,7 +446,7 @@ void MachineBasicBlock::updateTerminator() { // Finally update the unconditional successor to be reached via a branch // if it would not be reached by fallthrough. if (!isLayoutSuccessor(TBB)) - TII->InsertBranch(*this, TBB, nullptr, Cond, dl); + TII->InsertBranch(*this, TBB, nullptr, Cond, DL); } } else { if (FBB) { @@ -451,10 +457,10 @@ void MachineBasicBlock::updateTerminator() { if (TII->ReverseBranchCondition(Cond)) return; TII->RemoveBranch(*this); - TII->InsertBranch(*this, FBB, nullptr, Cond, dl); + TII->InsertBranch(*this, FBB, nullptr, Cond, DL); } else if (isLayoutSuccessor(FBB)) { TII->RemoveBranch(*this); - TII->InsertBranch(*this, TBB, nullptr, Cond, dl); + TII->InsertBranch(*this, TBB, nullptr, Cond, DL); } } else { // Walk through the successors and find the successor which is not @@ -478,7 +484,7 @@ void MachineBasicBlock::updateTerminator() { // Finally update the unconditional successor to be reached via a branch // if it would not be reached by fallthrough. if (!isLayoutSuccessor(TBB)) - TII->InsertBranch(*this, TBB, nullptr, Cond, dl); + TII->InsertBranch(*this, TBB, nullptr, Cond, DL); return; } @@ -487,45 +493,60 @@ void MachineBasicBlock::updateTerminator() { if (TII->ReverseBranchCondition(Cond)) { // We can't reverse the condition, add an unconditional branch. Cond.clear(); - TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, dl); + TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, DL); return; } TII->RemoveBranch(*this); - TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, dl); + TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, DL); } else if (!isLayoutSuccessor(FallthroughBB)) { TII->RemoveBranch(*this); - TII->InsertBranch(*this, TBB, FallthroughBB, Cond, dl); + TII->InsertBranch(*this, TBB, FallthroughBB, Cond, DL); } } } } -void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ, uint32_t weight) { +void MachineBasicBlock::addSuccessor(MachineBasicBlock *Succ, uint32_t Weight) { + // Weight list is either empty (if successor list isn't empty, this means + // disabled optimization) or has the same size as successor list. + if (!(Weights.empty() && !Successors.empty())) + Weights.push_back(Weight); + Successors.push_back(Succ); + Succ->addPredecessor(this); +} - // If we see non-zero value for the first time it means we actually use Weight - // list, so we fill all Weights with 0's. - if (weight != 0 && Weights.empty()) - Weights.resize(Successors.size()); +void MachineBasicBlock::addSuccessorWithoutWeight(MachineBasicBlock *Succ) { + // We need to make sure weight list is either empty or has the same size of + // successor list. When this function is called, we can safely delete all + // weight in the list. + Weights.clear(); + Successors.push_back(Succ); + Succ->addPredecessor(this); +} - if (weight != 0 || !Weights.empty()) - Weights.push_back(weight); +void MachineBasicBlock::addSuccessor(MachineBasicBlock *Succ, + BranchProbability Prob) { + // Probability list is either empty (if successor list isn't empty, this means + // disabled optimization) or has the same size as successor list. + if (!(Probs.empty() && !Successors.empty())) + Probs.push_back(Prob); + Successors.push_back(Succ); + Succ->addPredecessor(this); +} - Successors.push_back(succ); - succ->addPredecessor(this); +void MachineBasicBlock::addSuccessorWithoutProb(MachineBasicBlock *Succ) { + // We need to make sure probability list is either empty or has the same size + // of successor list. When this function is called, we can safely delete all + // probability in the list. + Probs.clear(); + Successors.push_back(Succ); + Succ->addPredecessor(this); } -void MachineBasicBlock::removeSuccessor(MachineBasicBlock *succ) { - succ->removePredecessor(this); - succ_iterator I = std::find(Successors.begin(), Successors.end(), succ); +void MachineBasicBlock::removeSuccessor(MachineBasicBlock *Succ) { + succ_iterator I = std::find(Successors.begin(), Successors.end(), Succ); assert(I != Successors.end() && "Not a current successor!"); - - // If Weight list is empty it means we don't use it (disabled optimization). - if (!Weights.empty()) { - weight_iterator WI = getWeightIterator(I); - Weights.erase(WI); - } - - Successors.erase(I); + removeSuccessor(I); } MachineBasicBlock::succ_iterator @@ -538,6 +559,13 @@ MachineBasicBlock::removeSuccessor(succ_iterator I) { Weights.erase(WI); } + // If probability list is empty it means we don't use it (disabled + // optimization). + if (!Probs.empty()) { + probability_iterator WI = getProbabilityIterator(I); + Probs.erase(WI); + } + (*I)->removePredecessor(this); return Successors.erase(I); } @@ -563,10 +591,10 @@ void MachineBasicBlock::replaceSuccessor(MachineBasicBlock *Old, } } assert(OldI != E && "Old is not a successor of this block"); - Old->removePredecessor(this); // If New isn't already a successor, let it take Old's place. if (NewI == E) { + Old->removePredecessor(this); New->addPredecessor(this); *OldI = New; return; @@ -574,60 +602,61 @@ void MachineBasicBlock::replaceSuccessor(MachineBasicBlock *Old, // New is already a successor. // Update its weight instead of adding a duplicate edge. - if (!Weights.empty()) { - weight_iterator OldWI = getWeightIterator(OldI); - *getWeightIterator(NewI) += *OldWI; - Weights.erase(OldWI); - } - Successors.erase(OldI); + if (!Weights.empty()) + *getWeightIterator(NewI) += *getWeightIterator(OldI); + // Update its probability instead of adding a duplicate edge. + if (!Probs.empty()) + *getProbabilityIterator(NewI) += *getProbabilityIterator(OldI); + + removeSuccessor(OldI); } -void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) { - Predecessors.push_back(pred); +void MachineBasicBlock::addPredecessor(MachineBasicBlock *Pred) { + Predecessors.push_back(Pred); } -void MachineBasicBlock::removePredecessor(MachineBasicBlock *pred) { - pred_iterator I = std::find(Predecessors.begin(), Predecessors.end(), pred); +void MachineBasicBlock::removePredecessor(MachineBasicBlock *Pred) { + pred_iterator I = std::find(Predecessors.begin(), Predecessors.end(), Pred); assert(I != Predecessors.end() && "Pred is not a predecessor of this block!"); Predecessors.erase(I); } -void MachineBasicBlock::transferSuccessors(MachineBasicBlock *fromMBB) { - if (this == fromMBB) +void MachineBasicBlock::transferSuccessors(MachineBasicBlock *FromMBB) { + if (this == FromMBB) return; - while (!fromMBB->succ_empty()) { - MachineBasicBlock *Succ = *fromMBB->succ_begin(); + while (!FromMBB->succ_empty()) { + MachineBasicBlock *Succ = *FromMBB->succ_begin(); uint32_t Weight = 0; // If Weight list is empty it means we don't use it (disabled optimization). - if (!fromMBB->Weights.empty()) - Weight = *fromMBB->Weights.begin(); + if (!FromMBB->Weights.empty()) + Weight = *FromMBB->Weights.begin(); addSuccessor(Succ, Weight); - fromMBB->removeSuccessor(Succ); + FromMBB->removeSuccessor(Succ); } } void -MachineBasicBlock::transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB) { - if (this == fromMBB) +MachineBasicBlock::transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB) { + if (this == FromMBB) return; - while (!fromMBB->succ_empty()) { - MachineBasicBlock *Succ = *fromMBB->succ_begin(); + while (!FromMBB->succ_empty()) { + MachineBasicBlock *Succ = *FromMBB->succ_begin(); uint32_t Weight = 0; - if (!fromMBB->Weights.empty()) - Weight = *fromMBB->Weights.begin(); + if (!FromMBB->Weights.empty()) + Weight = *FromMBB->Weights.begin(); addSuccessor(Succ, Weight); - fromMBB->removeSuccessor(Succ); + FromMBB->removeSuccessor(Succ); // Fix up any PHI nodes in the successor. for (MachineBasicBlock::instr_iterator MI = Succ->instr_begin(), ME = Succ->instr_end(); MI != ME && MI->isPHI(); ++MI) for (unsigned i = 2, e = MI->getNumOperands()+1; i != e; i += 2) { MachineOperand &MO = MI->getOperand(i); - if (MO.getMBB() == fromMBB) + if (MO.getMBB() == FromMBB) MO.setMBB(this); } } @@ -647,14 +676,14 @@ bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const { } bool MachineBasicBlock::canFallThrough() { - MachineFunction::iterator Fallthrough = this; + MachineFunction::iterator Fallthrough = getIterator(); ++Fallthrough; // If FallthroughBlock is off the end of the function, it can't fall through. if (Fallthrough == getParent()->end()) return false; // If FallthroughBlock isn't a successor, no fallthrough is possible. - if (!isSuccessor(Fallthrough)) + if (!isSuccessor(&*Fallthrough)) return false; // Analyze the branches, if any, at the end of the block. @@ -696,7 +725,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { return nullptr; MachineFunction *MF = getParent(); - DebugLoc dl; // FIXME: this is nowhere + DebugLoc DL; // FIXME: this is nowhere // Performance might be harmed on HW that implements branching using exec mask // where both sides of the branches are always executed. @@ -745,7 +774,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { if (LV) for (instr_iterator I = getFirstInstrTerminator(), E = instr_end(); I != E; ++I) { - MachineInstr *MI = I; + MachineInstr *MI = &*I; for (MachineInstr::mop_iterator OI = MI->operands_begin(), OE = MI->operands_end(); OI != OE; ++OI) { if (!OI->isReg() || OI->getReg() == 0 || @@ -765,7 +794,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { if (LIS) { for (instr_iterator I = getFirstInstrTerminator(), E = instr_end(); I != E; ++I) { - MachineInstr *MI = I; + MachineInstr *MI = &*I; for (MachineInstr::mop_iterator OI = MI->operands_begin(), OE = MI->operands_end(); OI != OE; ++OI) { @@ -787,7 +816,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { if (Indexes) { for (instr_iterator I = getFirstInstrTerminator(), E = instr_end(); I != E; ++I) - Terminators.push_back(I); + Terminators.push_back(&*I); } updateTerminator(); @@ -796,7 +825,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { SmallVector NewTerminators; for (instr_iterator I = getFirstInstrTerminator(), E = instr_end(); I != E; ++I) - NewTerminators.push_back(I); + NewTerminators.push_back(&*I); for (SmallVectorImpl::iterator I = Terminators.begin(), E = Terminators.end(); I != E; ++I) { @@ -810,16 +839,16 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { NMBB->addSuccessor(Succ); if (!NMBB->isLayoutSuccessor(Succ)) { Cond.clear(); - TII->InsertBranch(*NMBB, Succ, nullptr, Cond, dl); + TII->InsertBranch(*NMBB, Succ, nullptr, Cond, DL); if (Indexes) { for (instr_iterator I = NMBB->instr_begin(), E = NMBB->instr_end(); I != E; ++I) { // Some instructions may have been moved to NMBB by updateTerminator(), // so we first remove any instruction that already has an index. - if (Indexes->hasIndex(I)) - Indexes->removeMachineInstrFromMaps(I); - Indexes->insertMachineInstrInMaps(I); + if (Indexes->hasIndex(&*I)) + Indexes->removeMachineInstrFromMaps(&*I); + Indexes->insertMachineInstrInMaps(&*I); } } } @@ -846,7 +875,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { if (!(--I)->addRegisterKilled(Reg, TRI, /* addIfNotFound= */ false)) continue; if (TargetRegisterInfo::isVirtualRegister(Reg)) - LV->getVarInfo(Reg).Kills.push_back(I); + LV->getVarInfo(Reg).Kills.push_back(&*I); DEBUG(dbgs() << "Restored terminator kill: " << *I); break; } @@ -966,7 +995,7 @@ static void unbundleSingleMI(MachineInstr *MI) { MachineBasicBlock::instr_iterator MachineBasicBlock::erase(MachineBasicBlock::instr_iterator I) { - unbundleSingleMI(I); + unbundleSingleMI(&*I); return Insts.erase(I); } @@ -1035,36 +1064,35 @@ void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old, /// Note it is possible that DestA and/or DestB are LandingPads. bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA, MachineBasicBlock *DestB, - bool isCond) { + bool IsCond) { // The values of DestA and DestB frequently come from a call to the // 'TargetInstrInfo::AnalyzeBranch' method. We take our meaning of the initial // values from there. // // 1. If both DestA and DestB are null, then the block ends with no branches // (it falls through to its successor). - // 2. If DestA is set, DestB is null, and isCond is false, then the block ends + // 2. If DestA is set, DestB is null, and IsCond is false, then the block ends // with only an unconditional branch. - // 3. If DestA is set, DestB is null, and isCond is true, then the block ends + // 3. If DestA is set, DestB is null, and IsCond is true, then the block ends // with a conditional branch that falls through to a successor (DestB). - // 4. If DestA and DestB is set and isCond is true, then the block ends with a + // 4. If DestA and DestB is set and IsCond is true, then the block ends with a // conditional branch followed by an unconditional branch. DestA is the // 'true' destination and DestB is the 'false' destination. bool Changed = false; - MachineFunction::iterator FallThru = - std::next(MachineFunction::iterator(this)); + MachineFunction::iterator FallThru = std::next(getIterator()); if (!DestA && !DestB) { // Block falls through to successor. - DestA = FallThru; - DestB = FallThru; + DestA = &*FallThru; + DestB = &*FallThru; } else if (DestA && !DestB) { - if (isCond) + if (IsCond) // Block ends in conditional jump that falls through to successor. - DestB = FallThru; + DestB = &*FallThru; } else { - assert(DestA && DestB && isCond && + assert(DestA && DestB && IsCond && "CFG in a bad state. Cannot correct CFG edges"); } @@ -1112,11 +1140,35 @@ uint32_t MachineBasicBlock::getSuccWeight(const_succ_iterator Succ) const { return *getWeightIterator(Succ); } +/// Return probability of the edge from this block to MBB. If probability list +/// is empty, return a default probability which is 1/N, where N is the number +/// of successors. If the probability of the given successor is unknown, then +/// sum up all known probabilities and return the complement of the sum divided +/// by the number of unknown probabilities. +BranchProbability +MachineBasicBlock::getSuccProbability(const_succ_iterator Succ) const { + if (Probs.empty()) + return BranchProbability(1, succ_size()); + + auto Prob = *getProbabilityIterator(Succ); + assert(!Prob.isUnknown()); + return Prob; +} + /// Set successor weight of a given iterator. -void MachineBasicBlock::setSuccWeight(succ_iterator I, uint32_t weight) { +void MachineBasicBlock::setSuccWeight(succ_iterator I, uint32_t Weight) { if (Weights.empty()) return; - *getWeightIterator(I) = weight; + *getWeightIterator(I) = Weight; +} + +/// Set successor probability of a given iterator. +void MachineBasicBlock::setSuccProbability(succ_iterator I, + BranchProbability Prob) { + assert(!Prob.isUnknown()); + if (Probs.empty()) + return; + *getProbabilityIterator(I) = Prob; } /// Return wight iterator corresonding to the I successor iterator. @@ -1137,6 +1189,25 @@ getWeightIterator(MachineBasicBlock::const_succ_iterator I) const { return Weights.begin() + index; } +/// Return probability iterator corresonding to the I successor iterator. +MachineBasicBlock::probability_iterator +MachineBasicBlock::getProbabilityIterator(MachineBasicBlock::succ_iterator I) { + assert(Probs.size() == Successors.size() && "Async probability list!"); + const size_t index = std::distance(Successors.begin(), I); + assert(index < Probs.size() && "Not a current successor!"); + return Probs.begin() + index; +} + +/// Return probability iterator corresonding to the I successor iterator +MachineBasicBlock::const_probability_iterator +MachineBasicBlock::getProbabilityIterator( + MachineBasicBlock::const_succ_iterator I) const { + assert(Probs.size() == Successors.size() && "Async probability list!"); + const size_t index = std::distance(Successors.begin(), I); + assert(index < Probs.size() && "Not a current successor!"); + return Probs.begin() + index; +} + /// Return whether (physical) register "Reg" has been ined and not ed /// as of just before "MI". /// @@ -1211,3 +1282,17 @@ MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI, // At this point we have no idea of the liveness of the register. return LQR_Unknown; } + +const uint32_t * +MachineBasicBlock::getBeginClobberMask(const TargetRegisterInfo *TRI) const { + // EH funclet entry does not preserve any registers. + return isEHFuncletEntry() ? TRI->getNoPreservedMask() : nullptr; +} + +const uint32_t * +MachineBasicBlock::getEndClobberMask(const TargetRegisterInfo *TRI) const { + // If we see a return block with successors, this must be a funclet return, + // which does not preserve any registers. If there are no successors, we don't + // care what kind of return it is, putting a mask after it is a no-op. + return isReturnBlock() && !succ_empty() ? TRI->getNoPreservedMask() : nullptr; +}