65#define DEBUG_TYPE "branch-folder"
67STATISTIC(NumDeadBlocks,
"Number of dead blocks removed");
68STATISTIC(NumBranchOpts,
"Number of branches optimized");
69STATISTIC(NumTailMerge ,
"Number of block tails merged");
70STATISTIC(NumHoist ,
"Number of times common instructions are hoisted");
71STATISTIC(NumTailCalls,
"Number of tail calls optimized");
79 cl::desc(
"Max number of predecessors to consider tail merging"),
85 cl::desc(
"Min number of instructions to consider tail merging"),
109 MachineFunctionProperties::Property::NoPHIs);
115char BranchFolderPass::ID = 0;
120 "Control Flow Optimizer",
false,
false)
123 if (skipFunction(MF.getFunction()))
129 bool EnableTailMerge = !MF.getTarget().requiresStructuredCFG() &&
132 getAnalysis<MachineBlockFrequencyInfoWrapperPass>().getMBFI());
134 EnableTailMerge,
true, MBBFreqInfo,
135 getAnalysis<MachineBranchProbabilityInfoWrapperPass>().getMBPI(),
136 &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI());
138 MF.getSubtarget().getRegisterInfo());
145 : EnableHoistCommonCode(CommonHoist), MinCommonTailLength(MinTailLength),
146 MBBFreqInfo(FreqInfo), MBPI(ProbInfo), PSI(PSI) {
149 EnableTailMerge = DefaultEnableTailMerge;
166 TriedMerging.erase(
MBB);
170 if (
MI.shouldUpdateCallSiteInfo())
175 EHScopeMembership.erase(
MBB);
184 if (!tii)
return false;
186 TriedMerging.clear();
189 AfterBlockPlacement = AfterPlacement;
195 if (MinCommonTailLength == 0) {
203 MRI.invalidateLiveness();
205 bool MadeChange =
false;
210 bool MadeChangeThisIteration =
true;
211 while (MadeChangeThisIteration) {
212 MadeChangeThisIteration = TailMergeBlocks(MF);
215 if (!AfterBlockPlacement || MadeChangeThisIteration)
216 MadeChangeThisIteration |= OptimizeBranches(MF);
217 if (EnableHoistCommonCode)
218 MadeChangeThisIteration |= HoistCommonCode(MF);
219 MadeChange |= MadeChangeThisIteration;
233 if (!
Op.isJTI())
continue;
236 JTIsLive.
set(
Op.getIndex());
242 for (
unsigned i = 0, e = JTIsLive.
size(); i != e; ++i)
243 if (!JTIsLive.
test(i)) {
257 unsigned Hash =
MI.getOpcode();
258 for (
unsigned i = 0, e =
MI.getNumOperands(); i != e; ++i) {
264 unsigned OperandHash = 0;
265 switch (
Op.getType()) {
267 OperandHash =
Op.getReg();
270 OperandHash =
Op.getImm();
273 OperandHash =
Op.getMBB()->getNumber();
278 OperandHash =
Op.getIndex();
284 OperandHash =
Op.getOffset();
290 Hash += ((OperandHash << 3) |
Op.getType()) << (i & 31);
306 return !(
MI.isDebugInstr() ||
MI.isCFIInstruction());
336 unsigned TailLen = 0;
340 if (MBBI1 == MBB1->
end() || MBBI2 == MBB2->
end())
342 if (!MBBI1->isIdenticalTo(*MBBI2) ||
348 MBBI1->isInlineAsm()) {
374 }
while (
I != OldInst);
383 "Can only handle full register.");
388 BuildMI(OldMBB, OldInst,
DL, TII->
get(TargetOpcode::IMPLICIT_DEF), Reg);
416 NewMBB->
splice(NewMBB->
end(), &CurMBB, BBI1, CurMBB.
end());
421 ML->addBasicBlockToLoop(NewMBB, *MLI);
430 const auto &EHScopeI = EHScopeMembership.find(&CurMBB);
431 if (EHScopeI != EHScopeMembership.end()) {
432 auto n = EHScopeI->second;
433 EHScopeMembership[NewMBB] = n;
444 for (;
I != E; ++
I) {
449 else if (
I->mayLoadOrStore())
472 if (
TBB == NextBB && !
Cond.empty() && !FBB) {
485BranchFolder::MergePotentialsElt::operator<(
const MergePotentialsElt &o)
const {
486 if (getHash() <
o.getHash())
488 if (getHash() >
o.getHash())
490 if (getBlock()->getNumber() <
o.getBlock()->getNumber())
492 if (getBlock()->getNumber() >
o.getBlock()->getNumber())
503 unsigned NumTerms = 0;
510 if (!
I->isTerminator())
break;
545 unsigned MinCommonTailLength,
unsigned &CommonTailLen,
554 if (!EHScopeMembership.
empty()) {
555 auto EHScope1 = EHScopeMembership.
find(MBB1);
556 assert(EHScope1 != EHScopeMembership.
end());
557 auto EHScope2 = EHScopeMembership.
find(MBB2);
558 assert(EHScope2 != EHScopeMembership.
end());
559 if (EHScope1->second != EHScope2->second)
564 if (CommonTailLen == 0)
568 << CommonTailLen <<
'\n');
578 bool FullBlockTail1 = I1 == MBB1->
begin();
579 bool FullBlockTail2 = I2 == MBB2->
begin();
586 if ((MBB1 == PredBB || MBB2 == PredBB) &&
587 (!AfterPlacement || MBB1->
succ_size() == 1)) {
590 if (CommonTailLen > NumTerms)
599 if (FullBlockTail1 && FullBlockTail2 &&
616 if (AfterPlacement && FullBlockTail1 && FullBlockTail2) {
622 return (
MBB != &*MF->
begin()) && std::prev(
I)->canFallThrough();
624 if (!BothFallThrough(MBB1) || !BothFallThrough(MBB2))
633 unsigned EffectiveTailLen = CommonTailLen;
634 if (SuccBB && MBB1 != PredBB && MBB2 != PredBB &&
635 (MBB1->
succ_size() == 1 || !AfterPlacement) &&
641 if (EffectiveTailLen >= MinCommonTailLength)
650 return EffectiveTailLen >= 2 && OptForSize &&
651 (FullBlockTail1 || FullBlockTail2);
654unsigned BranchFolder::ComputeSameTails(
unsigned CurHash,
655 unsigned MinCommonTailLength,
658 unsigned maxCommonTailLength = 0
U;
661 MPIterator HighestMPIter = std::prev(MergePotentials.end());
662 for (MPIterator CurMPIter = std::prev(MergePotentials.end()),
663 B = MergePotentials.begin();
664 CurMPIter !=
B && CurMPIter->getHash() == CurHash; --CurMPIter) {
665 for (MPIterator
I = std::prev(CurMPIter);
I->getHash() == CurHash; --
I) {
666 unsigned CommonTailLen;
669 CommonTailLen, TrialBBI1, TrialBBI2,
672 AfterBlockPlacement, MBBFreqInfo, PSI)) {
673 if (CommonTailLen > maxCommonTailLength) {
675 maxCommonTailLength = CommonTailLen;
676 HighestMPIter = CurMPIter;
677 SameTails.push_back(SameTailElt(CurMPIter, TrialBBI1));
679 if (HighestMPIter == CurMPIter &&
680 CommonTailLen == maxCommonTailLength)
681 SameTails.push_back(SameTailElt(
I, TrialBBI2));
687 return maxCommonTailLength;
690void BranchFolder::RemoveBlocksWithHash(
unsigned CurHash,
694 MPIterator CurMPIter,
B;
695 for (CurMPIter = std::prev(MergePotentials.end()),
696 B = MergePotentials.begin();
697 CurMPIter->getHash() == CurHash; --CurMPIter) {
700 if (SuccBB && CurMBB != PredBB)
701 FixTail(CurMBB, SuccBB, TII, BranchDL);
705 if (CurMPIter->getHash() != CurHash)
707 MergePotentials.erase(CurMPIter, MergePotentials.end());
712 unsigned maxCommonTailLength,
713 unsigned &commonTailIndex) {
715 unsigned TimeEstimate = ~0
U;
716 for (
unsigned i = 0, e = SameTails.size(); i != e; ++i) {
718 if (SameTails[i].getBlock() == PredBB) {
725 SameTails[i].getTailStartPos());
726 if (t <= TimeEstimate) {
733 SameTails[commonTailIndex].getTailStartPos();
737 << maxCommonTailLength);
750 SameTails[commonTailIndex].setBlock(newMBB);
751 SameTails[commonTailIndex].setTailStartPos(newMBB->
begin());
767 unsigned CommonTailLen = 0;
768 for (
auto E =
MBB->
end(); MBBIStartPos != E; ++MBBIStartPos)
776 while (CommonTailLen--) {
777 assert(
MBBI != MBBIE &&
"Reached BB end within common tail length!");
788 assert(MBBICommon != MBBIECommon &&
789 "Reached BB end within common tail length!");
790 assert(MBBICommon->isIdenticalTo(*
MBBI) &&
"Expected matching MIIs!");
793 if (MBBICommon->mayLoadOrStore())
794 MBBICommon->cloneMergedMemRefs(*
MBB->
getParent(), {&*MBBICommon, &*MBBI});
796 for (
unsigned I = 0, E = MBBICommon->getNumOperands();
I != E; ++
I) {
810void BranchFolder::mergeCommonTails(
unsigned commonTailIndex) {
813 std::vector<MachineBasicBlock::iterator> NextCommonInsts(SameTails.size());
814 for (
unsigned int i = 0 ; i != SameTails.size() ; ++i) {
815 if (i != commonTailIndex) {
816 NextCommonInsts[i] = SameTails[i].getTailStartPos();
820 "MBB is not a common tail only block");
824 for (
auto &
MI : *
MBB) {
828 for (
unsigned int i = 0 ; i < NextCommonInsts.size() ; i++) {
829 if (i == commonTailIndex)
832 auto &Pos = NextCommonInsts[i];
833 assert(Pos != SameTails[i].getBlock()->
end() &&
834 "Reached BB end within common tail");
837 assert(Pos != SameTails[i].getBlock()->
end() &&
838 "Reached BB end within common tail");
840 assert(
MI.isIdenticalTo(*Pos) &&
"Expected matching MIIs!");
842 NextCommonInsts[i] = ++Pos;
865 return NewLiveIns.contains(SReg) && !MRI->isReserved(SReg);
870 BuildMI(*Pred, InsertBefore,
DL, TII->
get(TargetOpcode::IMPLICIT_DEF),
891 unsigned MinCommonTailLength) {
892 bool MadeChange =
false;
895 dbgs() <<
"\nTryTailMergeBlocks: ";
896 for (
unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
898 << (i ==
e - 1 ?
"" :
", ");
906 dbgs() <<
"Looking for common tails of at least " << MinCommonTailLength
907 <<
" instruction" << (MinCommonTailLength == 1 ?
"" :
"s") <<
'\n';
915 while (MergePotentials.size() > 1) {
916 unsigned CurHash = MergePotentials.back().getHash();
917 const DebugLoc &BranchDL = MergePotentials.back().getBranchDebugLoc();
921 unsigned maxCommonTailLength = ComputeSameTails(CurHash,
927 if (SameTails.empty()) {
928 RemoveBlocksWithHash(CurHash, SuccBB, PredBB, BranchDL);
937 &MergePotentials.front().getBlock()->getParent()->front();
938 unsigned commonTailIndex = SameTails.size();
941 if (SameTails.size() == 2 &&
942 SameTails[0].getBlock()->isLayoutSuccessor(SameTails[1].getBlock()) &&
943 SameTails[1].tailIsWholeBlock() && !SameTails[1].getBlock()->isEHPad())
945 else if (SameTails.size() == 2 &&
946 SameTails[1].getBlock()->isLayoutSuccessor(
947 SameTails[0].getBlock()) &&
948 SameTails[0].tailIsWholeBlock() &&
949 !SameTails[0].getBlock()->isEHPad())
954 for (
unsigned i = 0, e = SameTails.size(); i != e; ++i) {
957 SameTails[i].tailIsWholeBlock())
963 if (SameTails[i].tailIsWholeBlock())
968 if (commonTailIndex == SameTails.size() ||
969 (SameTails[commonTailIndex].getBlock() == PredBB &&
970 !SameTails[commonTailIndex].tailIsWholeBlock())) {
973 if (!CreateCommonTailOnlyBlock(PredBB, SuccBB,
974 maxCommonTailLength, commonTailIndex)) {
975 RemoveBlocksWithHash(CurHash, SuccBB, PredBB, BranchDL);
983 setCommonTailEdgeWeights(*
MBB);
987 mergeCommonTails(commonTailIndex);
993 for (
unsigned int i=0, e = SameTails.size(); i != e; ++i) {
994 if (commonTailIndex == i)
997 << (i == e - 1 ?
"" :
", "));
999 replaceTailWithBranchTo(SameTails[i].getTailStartPos(), *
MBB);
1001 MergePotentials.erase(SameTails[i].getMPIter());
1012 bool MadeChange =
false;
1013 if (!EnableTailMerge)
1018 MergePotentials.clear();
1030 for (
const MergePotentialsElt &Elt : MergePotentials)
1031 TriedMerging.insert(Elt.getBlock());
1034 if (MergePotentials.size() >= 2)
1035 MadeChange |= TryTailMergeBlocks(
nullptr,
nullptr, MinCommonTailLength);
1058 if (
I->pred_size() < 2)
continue;
1062 MergePotentials.clear();
1075 if (AfterBlockPlacement && MLI) {
1077 if (
ML && IBB ==
ML->getHeader())
1085 if (TriedMerging.count(PBB))
1093 if (!UniquePreds.
insert(PBB).second)
1098 if (PBB->hasEHPadSuccessor() || PBB->mayHaveInlineAsmBr())
1104 if (AfterBlockPlacement && MLI)
1114 if (!
Cond.empty() &&
TBB == IBB) {
1119 auto Next = ++PBB->getIterator();
1120 if (Next != MF.end())
1126 DebugLoc dl = PBB->findBranchDebugLoc();
1127 if (
TBB && (
Cond.empty() || FBB)) {
1135 MergePotentials.push_back(
1143 for (MergePotentialsElt &Elt : MergePotentials)
1144 TriedMerging.insert(Elt.getBlock());
1146 if (MergePotentials.size() >= 2)
1147 MadeChange |= TryTailMergeBlocks(IBB, PredBB, MinCommonTailLength);
1151 PredBB = &*std::prev(
I);
1152 if (MergePotentials.size() == 1 &&
1153 MergePotentials.begin()->getBlock() != PredBB)
1154 FixTail(MergePotentials.begin()->getBlock(), IBB, TII,
1155 MergePotentials.begin()->getBranchDebugLoc());
1168 for (
const auto &Src : SameTails) {
1171 AccumulatedMBBFreq += BlockFreq;
1178 auto EdgeFreq = EdgeFreqLs.begin();
1181 SuccI != SuccE; ++SuccI, ++EdgeFreq)
1185 MBBFreqInfo.
setBlockFreq(&TailMBB, AccumulatedMBBFreq);
1191 std::accumulate(EdgeFreqLs.begin(), EdgeFreqLs.end(),
BlockFrequency(0))
1193 auto EdgeFreq = EdgeFreqLs.begin();
1195 if (SumEdgeFreq > 0) {
1197 SuccI != SuccE; ++SuccI, ++EdgeFreq) {
1199 EdgeFreq->getFrequency(), SumEdgeFreq);
1210 bool MadeChange =
false;
1219 MadeChange |= OptimizeBlock(&
MBB);
1223 RemoveDeadBlock(&
MBB);
1243 return I->isBranch();
1252 assert(MBB1 && MBB2 &&
"Unknown MachineBasicBlock");
1260 if (MBB1I == MBB1->
end() || MBB2I == MBB2->
end())
1268 return MBB2I->isCall() && !MBB1I->isCall();
1275 if (
I !=
MBB.
end() &&
I->isBranch())
1276 return I->getDebugLoc();
1285 if (
MI.isDebugInstr()) {
1286 TII->duplicate(PredMBB, InsertBefore,
MI);
1287 LLVM_DEBUG(
dbgs() <<
"Copied debug entity from empty block to pred: "
1297 if (
MI.isDebugInstr()) {
1298 TII->duplicate(SuccMBB, InsertBefore,
MI);
1299 LLVM_DEBUG(
dbgs() <<
"Copied debug entity from empty block to succ: "
1328 bool MadeChange =
false;
1336 bool SameEHScope =
true;
1337 if (!EHScopeMembership.empty() && FallThrough != MF.
end()) {
1338 auto MBBEHScope = EHScopeMembership.find(
MBB);
1339 assert(MBBEHScope != EHScopeMembership.end());
1340 auto FallThroughEHScope = EHScopeMembership.find(&*FallThrough);
1341 assert(FallThroughEHScope != EHScopeMembership.end());
1342 SameEHScope = MBBEHScope->second == FallThroughEHScope->second;
1349 bool CurUnAnalyzable =
1362 if (FallThrough == MF.
end()) {
1364 }
else if (FallThrough->isEHPad()) {
1380 if (*SI != &*FallThrough && !FallThrough->isSuccessor(*SI)) {
1381 assert((*SI)->isEHPad() &&
"Bad CFG");
1382 FallThrough->copySuccessor(
MBB, SI);
1387 MJTI->ReplaceMBBInJumpTables(
MBB, &*FallThrough);
1399 bool PriorUnAnalyzable =
1400 TII->
analyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond,
true);
1401 if (!PriorUnAnalyzable) {
1405 if (PriorTBB && PriorTBB == PriorFBB) {
1409 if (PriorTBB !=
MBB)
1410 TII->
insertBranch(PrevBB, PriorTBB,
nullptr, PriorCond, dl);
1413 goto ReoptimizeBlock;
1427 <<
"From MBB: " << *
MBB);
1429 if (!PrevBB.
empty()) {
1435 while (PrevBBIter != PrevBB.
begin() && MBBIter !=
MBB->
end()
1436 && PrevBBIter->isDebugInstr() && MBBIter->isDebugInstr()) {
1437 if (!MBBIter->isIdenticalTo(*PrevBBIter))
1440 ++MBBIter; -- PrevBBIter;
1454 if (PriorTBB ==
MBB && !PriorFBB) {
1458 goto ReoptimizeBlock;
1463 if (PriorFBB ==
MBB) {
1466 TII->
insertBranch(PrevBB, PriorTBB,
nullptr, PriorCond, dl);
1469 goto ReoptimizeBlock;
1475 if (PriorTBB ==
MBB) {
1480 TII->
insertBranch(PrevBB, PriorFBB,
nullptr, NewPriorCond, dl);
1483 goto ReoptimizeBlock;
1498 bool DoTransform =
true;
1505 if (FallThrough == --MF.
end() &&
1507 DoTransform =
false;
1514 <<
"To make fallthrough to: " << *PriorTBB <<
"\n");
1537 bool PredAnalyzable =
1538 !TII->
analyzeBranch(*Pred, PredTBB, PredFBB, PredCond,
true);
1541 if (PredAnalyzable && !PredCond.
empty() && PredTBB ==
MBB &&
1542 PredTBB != PredFBB) {
1560 if (!PredsChanged.
empty()) {
1561 NumTailCalls += PredsChanged.
size();
1562 for (
auto &Pred : PredsChanged)
1570 if (!CurUnAnalyzable) {
1576 if (CurTBB && CurFBB && CurFBB ==
MBB && CurTBB !=
MBB) {
1584 goto ReoptimizeBlock;
1590 if (CurTBB && CurCond.
empty() && !CurFBB &&
1613 if (PredHasNoFallThrough || !PriorUnAnalyzable ||
1618 PriorTBB !=
MBB && PriorFBB !=
MBB) {
1621 "Bad branch analysis");
1624 assert(!PriorFBB &&
"Machine CFG out of date!");
1629 TII->
insertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl);
1634 bool DidChange =
false;
1635 bool HasBranchToSelf =
false;
1641 HasBranchToSelf =
true;
1651 assert((*SI)->isEHPad() &&
"Bad CFG");
1660 *PMBB, NewCurTBB, NewCurFBB, NewCurCond,
true);
1661 if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
1665 TII->
insertBranch(*PMBB, NewCurTBB,
nullptr, NewCurCond, pdl);
1674 MJTI->ReplaceMBBInJumpTables(
MBB, CurTBB);
1678 if (!HasBranchToSelf)
return MadeChange;
1705 !TII->
analyzeBranch(*PredBB, PredTBB, PredFBB, PredCond,
true) &&
1706 (PredTBB ==
MBB || PredFBB ==
MBB) &&
1707 (!CurFallsThru || !CurTBB || !CurFBB) &&
1726 goto ReoptimizeBlock;
1731 if (!CurFallsThru) {
1734 if (!CurUnAnalyzable) {
1744 if (SuccBB !=
MBB && &*SuccPrev !=
MBB &&
1745 !SuccPrev->canFallThrough()) {
1748 goto ReoptimizeBlock;
1769 if (FallThrough != MF.
end() &&
1770 !FallThrough->isEHPad() &&
1771 !TII->
analyzeBranch(PrevBB, PrevTBB, PrevFBB, PrevCond,
true) &&
1788 bool MadeChange =
false;
1790 MadeChange |= HoistCommonCodeInSuccs(&
MBB);
1800 if (SuccBB != TrueBB)
1805template <
class Container>
1808 if (Reg.isPhysical()) {
1830 if (!
TII->isUnpredicatedTerminator(*Loc))
1871 if (!MO.isReg() || MO.isUse())
1876 if (
Uses.count(Reg)) {
1892 bool DontMoveAcrossStore =
true;
1907 if (
Uses.erase(Reg)) {
1908 if (Reg.isPhysical()) {
1945 bool HasDups =
false;
1951 while (TIB != TIE && FIB != FIE) {
1955 if (TIB == TIE || FIB == FIE)
1968 if (MO.isRegMask()) {
1978 if (
Uses.count(Reg)) {
1985 if (Defs.
count(Reg) && !MO.isDead()) {
2000 }
else if (!ActiveDefsSet.
count(Reg)) {
2001 if (Defs.
count(Reg)) {
2007 if (MO.isKill() &&
Uses.count(Reg))
2010 MO.setIsKill(
false);
2016 bool DontMoveAcrossStore =
true;
2017 if (!TIB->isSafeToMove(DontMoveAcrossStore))
2027 if (!AllDefsSet.
count(Reg)) {
2030 if (
Reg.isPhysical()) {
2032 ActiveDefsSet.
erase(*AI);
2034 ActiveDefsSet.
erase(Reg);
2043 if (!Reg ||
Reg.isVirtual())
2058 FBB->erase(FBB->begin(), FIB);
unsigned const MachineRegisterInfo * MRI
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
MachineBasicBlock MachineBasicBlock::iterator MBBI
This file implements the BitVector class.
static unsigned EstimateRuntime(MachineBasicBlock::iterator I, MachineBasicBlock::iterator E)
EstimateRuntime - Make a rough estimate for how long it will take to run the specified code.
static unsigned ComputeCommonTailLength(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2, MachineBasicBlock::iterator &I1, MachineBasicBlock::iterator &I2)
Given two machine basic blocks, return the number of instructions they actually have in common togeth...
static MachineBasicBlock * findFalseBlock(MachineBasicBlock *BB, MachineBasicBlock *TrueBB)
findFalseBlock - BB has a fallthrough.
static void copyDebugInfoToPredecessor(const TargetInstrInfo *TII, MachineBasicBlock &MBB, MachineBasicBlock &PredMBB)
static unsigned HashMachineInstr(const MachineInstr &MI)
HashMachineInstr - Compute a hash value for MI and its operands.
static bool countsAsInstruction(const MachineInstr &MI)
Whether MI should be counted as an instruction when calculating common tail.
static unsigned CountTerminators(MachineBasicBlock *MBB, MachineBasicBlock::iterator &I)
CountTerminators - Count the number of terminators in the given block and set I to the position of th...
static bool blockEndsInUnreachable(const MachineBasicBlock *MBB)
A no successor, non-return block probably ends in unreachable and is cold.
static void salvageDebugInfoFromEmptyBlock(const TargetInstrInfo *TII, MachineBasicBlock &MBB)
static MachineBasicBlock::iterator skipBackwardPastNonInstructions(MachineBasicBlock::iterator I, MachineBasicBlock *MBB)
Iterate backwards from the given iterator I, towards the beginning of the block.
static cl::opt< unsigned > TailMergeThreshold("tail-merge-threshold", cl::desc("Max number of predecessors to consider tail merging"), cl::init(150), cl::Hidden)
static void addRegAndItsAliases(Register Reg, const TargetRegisterInfo *TRI, Container &Set)
static cl::opt< cl::boolOrDefault > FlagEnableTailMerge("enable-tail-merge", cl::init(cl::BOU_UNSET), cl::Hidden)
static cl::opt< unsigned > TailMergeSize("tail-merge-size", cl::desc("Min number of instructions to consider tail merging"), cl::init(3), cl::Hidden)
static bool IsEmptyBlock(MachineBasicBlock *MBB)
static bool ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2, unsigned MinCommonTailLength, unsigned &CommonTailLen, MachineBasicBlock::iterator &I1, MachineBasicBlock::iterator &I2, MachineBasicBlock *SuccBB, MachineBasicBlock *PredBB, DenseMap< const MachineBasicBlock *, int > &EHScopeMembership, bool AfterPlacement, MBFIWrapper &MBBFreqInfo, ProfileSummaryInfo *PSI)
ProfitableToMerge - Check if two machine basic blocks have a common tail and decide if it would be pr...
static void copyDebugInfoToSuccessor(const TargetInstrInfo *TII, MachineBasicBlock &MBB, MachineBasicBlock &SuccMBB)
static bool IsBranchOnlyBlock(MachineBasicBlock *MBB)
static void FixTail(MachineBasicBlock *CurMBB, MachineBasicBlock *SuccBB, const TargetInstrInfo *TII, const DebugLoc &BranchDL)
static bool IsBetterFallthrough(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2)
IsBetterFallthrough - Return true if it would be clearly better to fall-through to MBB1 than to fall ...
static unsigned HashEndOfMBB(const MachineBasicBlock &MBB)
HashEndOfMBB - Hash the last instruction in the MBB.
static void mergeOperations(MachineBasicBlock::iterator MBBIStartPos, MachineBasicBlock &MBBCommon)
static MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB, const TargetInstrInfo *TII, const TargetRegisterInfo *TRI, SmallSet< Register, 4 > &Uses, SmallSet< Register, 4 > &Defs)
findHoistingInsertPosAndDeps - Find the location to move common instructions in successors to.
static DebugLoc getBranchDebugLoc(MachineBasicBlock &MBB)
getBranchDebugLoc - Find and return, if any, the DebugLoc of the branch instructions on the block.
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
const HexagonInstrInfo * TII
A common definition of LaneBitmask for use in TableGen and CodeGen.
unsigned const TargetRegisterInfo * TRI
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
const SmallVectorImpl< MachineOperand > MachineBasicBlock * TBB
const SmallVectorImpl< MachineOperand > & Cond
Remove Loads Into Fake Uses
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This file defines the SmallSet class.
This file defines the SmallVector class.
This file defines the 'Statistic' class, which is designed to be an easy way to expose various metric...
#define STATISTIC(VARNAME, DESC)
Target-Independent Code Generator Pass Configuration Options pass.
Represent the analysis usage information of a pass.
AnalysisUsage & addRequired()
LLVM Basic Block Representation.
bool test(unsigned Idx) const
size_type size() const
size - Returns the number of bits in this bitvector.
bool OptimizeFunction(MachineFunction &MF, const TargetInstrInfo *tii, const TargetRegisterInfo *tri, MachineLoopInfo *mli=nullptr, bool AfterPlacement=false)
Perhaps branch folding, tail merging and other CFG optimizations on the given function.
BranchFolder(bool DefaultEnableTailMerge, bool CommonHoist, MBFIWrapper &FreqInfo, const MachineBranchProbabilityInfo &ProbInfo, ProfileSummaryInfo *PSI, unsigned MinTailLength=0)
static BranchProbability getBranchProbability(uint64_t Numerator, uint64_t Denominator)
static DILocation * getMergedLocation(DILocation *LocA, DILocation *LocB)
When two instructions are combined into a single instruction we also need to combine the original loc...
This class represents an Operation in the Expression.
iterator find(const_arg_type_t< KeyT > Val)
unsigned removeBranch(MachineBasicBlock &MBB, int *BytesRemoved=nullptr) const override
Remove the branching code at the end of the specific MBB.
bool isPredicated(const MachineInstr &MI) const override
Returns true if the instruction is already predicated.
bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, MachineBasicBlock *&FBB, SmallVectorImpl< MachineOperand > &Cond, bool AllowModify) const override
Analyze the branching code at the end of MBB, returning true if it cannot be understood (e....
bool reverseBranchCondition(SmallVectorImpl< MachineOperand > &Cond) const override
Reverses the branch condition of the specified condition list, returning false on success and true if...
unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB, ArrayRef< MachineOperand > Cond, const DebugLoc &DL, int *BytesAdded=nullptr) const override
Insert branch code into the end of the specified MachineBasicBlock.
A set of physical registers with utility functions to track liveness when walking backward/forward th...
void clear()
Clears the set.
bool available(const MachineRegisterInfo &MRI, MCPhysReg Reg) const
Returns true if register Reg and no aliasing register is in the set.
void stepBackward(const MachineInstr &MI)
Simulates liveness when stepping backwards over an instruction(bundle).
void init(const TargetRegisterInfo &TRI)
(re-)initializes and clears the set.
void addLiveOuts(const MachineBasicBlock &MBB)
Adds all live-out registers of basic block MBB.
void removeBlock(BlockT *BB)
This method completely removes BB from all data structures, including all of the Loop objects it is n...
LoopT * getLoopFor(const BlockT *BB) const
Return the inner most loop that BB lives in.
BlockFrequency getBlockFreq(const MachineBasicBlock *MBB) const
void setBlockFreq(const MachineBasicBlock *MBB, BlockFrequency F)
const MCInstrDesc & get(unsigned Opcode) const
Return the machine instruction descriptor that corresponds to the specified instruction opcode.
MCRegAliasIterator enumerates all registers aliasing Reg.
iterator_range< MCSuperRegIterator > superregs(MCRegister Reg) const
Return an iterator range over all super-registers of Reg, excluding Reg.
unsigned pred_size() const
bool isEHPad() const
Returns true if the block is a landing pad.
void moveBefore(MachineBasicBlock *NewAfter)
Move 'this' block before or after the specified block.
void transferSuccessors(MachineBasicBlock *FromMBB)
Transfers all the successors from MBB to this machine basic block (i.e., copies all the successors Fr...
iterator_range< livein_iterator > liveins() const
int getNumber() const
MachineBasicBlocks are uniquely numbered at the function level, unless they're not in a MachineFuncti...
iterator SkipPHIsAndLabels(iterator I)
Return the first instruction in MBB after I that is not a PHI or a label.
const BasicBlock * getBasicBlock() const
Return the LLVM basic block that this instance corresponded to originally.
bool canFallThrough()
Return true if the block can implicitly transfer control to the block after it by falling off the end...
void setSuccProbability(succ_iterator I, BranchProbability Prob)
Set successor probability of a given iterator.
iterator getFirstNonDebugInstr(bool SkipPseudoOp=true)
Returns an iterator to the first non-debug instruction in the basic block, or end().
succ_iterator succ_begin()
void clearLiveIns()
Clear live in list.
iterator getFirstTerminator()
Returns an iterator to the first terminator instruction of this basic block.
unsigned succ_size() const
bool hasAddressTaken() const
Test whether this block is used as something other than the target of a terminator,...
void addSuccessor(MachineBasicBlock *Succ, BranchProbability Prob=BranchProbability::getUnknown())
Add Succ as a successor of this MachineBasicBlock.
void copySuccessor(const MachineBasicBlock *Orig, succ_iterator I)
Copy a successor (and any probability info) from original block to this block's.
void removeSuccessor(MachineBasicBlock *Succ, bool NormalizeSuccProbs=false)
Remove successor from the successors list of this MachineBasicBlock.
pred_iterator pred_begin()
iterator getLastNonDebugInstr(bool SkipPseudoOp=true)
Returns an iterator to the last non-debug instruction in the basic block, or end().
void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New)
Given a machine basic block that branched to 'Old', change the code and CFG so that it branches to 'N...
bool isLayoutSuccessor(const MachineBasicBlock *MBB) const
Return true if the specified MBB will be emitted immediately after this block, such that if this bloc...
const MachineFunction * getParent() const
Return the MachineFunction containing this basic block.
instr_iterator erase(instr_iterator I)
Remove an instruction from the instruction list and delete it.
DebugLoc findBranchDebugLoc()
Find and return the merged DebugLoc of the branch instructions of the block.
iterator_range< succ_iterator > successors()
reverse_iterator rbegin()
bool isMachineBlockAddressTaken() const
Test whether this block is used as something other than the target of a terminator,...
bool isSuccessor(const MachineBasicBlock *MBB) const
Return true if the specified MBB is a successor of this block.
iterator_range< pred_iterator > predecessors()
void splice(iterator Where, MachineBasicBlock *Other, iterator From)
Take an instruction from MBB 'Other' at the position From, and insert it into this MBB right before '...
void moveAfter(MachineBasicBlock *NewBefore)
BranchProbability getEdgeProbability(const MachineBasicBlock *Src, const MachineBasicBlock *Dst) const
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
virtual bool runOnMachineFunction(MachineFunction &MF)=0
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
virtual MachineFunctionProperties getRequiredProperties() const
Properties which a MachineFunction may have at a given point in time.
MachineFunctionProperties & set(Property P)
MachineRegisterInfo & getRegInfo()
getRegInfo - Return information about the registers currently in use.
const MachineBasicBlock & back() const
void eraseCallSiteInfo(const MachineInstr *MI)
Following functions update call site info.
void RenumberBlocks(MachineBasicBlock *MBBFrom=nullptr)
RenumberBlocks - This discards all of the MachineBasicBlock numbers and recomputes them.
const MachineJumpTableInfo * getJumpTableInfo() const
getJumpTableInfo - Return the jump table info object for the current function.
MachineBasicBlock * CreateMachineBasicBlock(const BasicBlock *BB=nullptr, std::optional< UniqueBBID > BBID=std::nullopt)
CreateMachineBasicBlock - Allocate a new MachineBasicBlock.
void erase(iterator MBBI)
void insert(iterator MBBI, MachineBasicBlock *MBB)
Representation of each machine instruction.
bool isReturn(QueryType Type=AnyInBundle) const
bool isBarrier(QueryType Type=AnyInBundle) const
Returns true if the specified instruction stops control flow from executing the instruction immediate...
void eraseFromParent()
Unlink 'this' from the containing basic block and delete it.
bool isIndirectBranch(QueryType Type=AnyInBundle) const
Return true if this is an indirect branch, such as a branch through a register.
void RemoveJumpTable(unsigned Idx)
RemoveJumpTable - Mark the specific index as being dead.
const std::vector< MachineJumpTableEntry > & getJumpTables() const
MachineOperand class - Representation of each machine instruction operand.
bool isReg() const
isReg - Tests if this is a MO_Register operand.
void setIsUndef(bool Val=true)
@ MO_Immediate
Immediate operand.
@ MO_ConstantPoolIndex
Address of indexed Constant in Constant Pool.
@ MO_GlobalAddress
Address of a global value.
@ MO_MachineBasicBlock
MachineBasicBlock reference.
@ MO_FrameIndex
Abstract Stack Frame Index.
@ MO_Register
Register operand.
@ MO_ExternalSymbol
Name of external global symbol.
@ MO_JumpTableIndex
Address of indexed Jump Table for switch.
MachineRegisterInfo - Keep track of information for virtual and physical registers,...
An analysis pass based on legacy pass manager to deliver ProfileSummaryInfo.
Analysis providing profile information.
Wrapper class representing virtual and physical registers.
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements.
SmallSet - This maintains a set of unique values, optimizing for the case when the set is small (less...
size_type count(const T &V) const
count - Return 1 if the element is in the set, 0 otherwise.
void push_back(const T &Elt)
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
TargetInstrInfo - Interface to description of machine instruction set.
virtual bool reverseBranchCondition(SmallVectorImpl< MachineOperand > &Cond) const
Reverses the branch condition of the specified condition list, returning false on success and true if...
virtual unsigned removeBranch(MachineBasicBlock &MBB, int *BytesRemoved=nullptr) const
Remove the branching code at the end of the specific MBB.
virtual bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, MachineBasicBlock *&FBB, SmallVectorImpl< MachineOperand > &Cond, bool AllowModify=false) const
Analyze the branching code at the end of MBB, returning true if it cannot be understood (e....
virtual bool canMakeTailCallConditional(SmallVectorImpl< MachineOperand > &Cond, const MachineInstr &TailCall) const
Returns true if the tail call can be made conditional on BranchCond.
virtual void ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail, MachineBasicBlock *NewDest) const
Delete the instruction OldInst and everything after it, replacing it with an unconditional branch to ...
virtual bool isUnconditionalTailCall(const MachineInstr &MI) const
Returns true if MI is an unconditional tail call.
virtual unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB, ArrayRef< MachineOperand > Cond, const DebugLoc &DL, int *BytesAdded=nullptr) const
Insert branch code into the end of the specified MachineBasicBlock.
virtual unsigned getTailMergeSize(const MachineFunction &MF) const
Returns the target-specific default value for tail merging.
virtual bool isPredicated(const MachineInstr &MI) const
Returns true if the instruction is already predicated.
virtual void replaceBranchWithTailCall(MachineBasicBlock &MBB, SmallVectorImpl< MachineOperand > &Cond, const MachineInstr &TailCall) const
Replace the conditional branch in MBB with a conditional tail call.
virtual bool isLegalToSplitMBBAt(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI) const
Return true if it's legal to split the given basic block at the specified instruction (i....
Target-Independent Code Generator Pass Configuration Options.
bool getEnableTailMerge() const
TargetRegisterInfo base class - We assume that the target defines a static array of TargetRegisterDes...
virtual bool trackLivenessAfterRegAlloc(const MachineFunction &MF) const
Returns true if the live-ins should be tracked after register allocation.
self_iterator getIterator()
unsigned ID
LLVM IR allows to use arbitrary numbers as calling convention identifiers.
Reg
All possible values of the reg field in the ModR/M byte.
initializer< Ty > init(const Ty &Val)
const_iterator begin(StringRef path, Style style=Style::native)
Get begin iterator over path.
const_iterator end(StringRef path)
Get end iterator over path.
This is an optimization pass for GlobalISel generic memory operations.
auto drop_begin(T &&RangeOrContainer, size_t N=1)
Return a range covering RangeOrContainer with the first N elements excluded.
MachineInstrBuilder BuildMI(MachineFunction &MF, const MIMetadata &MIMD, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
bool shouldOptimizeForSize(const MachineFunction *MF, ProfileSummaryInfo *PSI, const MachineBlockFrequencyInfo *BFI, PGSOQueryType QueryType=PGSOQueryType::Other)
Returns true if machine function MF is suggested to be size-optimized based on the profile.
iterator_range< early_inc_iterator_impl< detail::IterOfRange< RangeT > > > make_early_inc_range(RangeT &&Range)
Make a range that does early increment to allow mutation of the underlying range without disrupting i...
IterT skipDebugInstructionsForward(IterT It, IterT End, bool SkipPseudoOp=true)
Increment It until it points to a non-debug instruction or to End and return the resulting iterator.
bool any_of(R &&range, UnaryPredicate P)
Provide wrappers to std::any_of which take ranges instead of having to pass begin/end explicitly.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
void computeAndAddLiveIns(LivePhysRegs &LiveRegs, MachineBasicBlock &MBB)
Convenience function combining computeLiveIns() and addLiveIns().
void array_pod_sort(IteratorTy Start, IteratorTy End)
array_pod_sort - This sorts an array with the specified start and end extent.
void computeLiveIns(LivePhysRegs &LiveRegs, const MachineBasicBlock &MBB)
Computes registers live-in to MBB assuming all of its successors live-in lists are up-to-date.
char & BranchFolderPassID
BranchFolding - This pass performs machine code CFG based optimizations to delete branches to branche...
IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp=true)
Decrement It, then continue decrementing it while it points to a debug instruction.
void fullyRecomputeLiveIns(ArrayRef< MachineBasicBlock * > MBBs)
Convenience function for recomputing live-in's for a set of MBBs until the computation converges.
Printable printMBBReference(const MachineBasicBlock &MBB)
Prints a machine basic block reference.
void addLiveIns(MachineBasicBlock &MBB, const LivePhysRegs &LiveRegs)
Adds registers contained in LiveRegs to the block live-in list of MBB.
DenseMap< const MachineBasicBlock *, int > getEHScopeMembership(const MachineFunction &MF)
static constexpr LaneBitmask getAll()
Pair of physical register and lane mask.