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"),
86 cl::desc(
"Min number of instructions to consider tail merging"),
110 MachineFunctionProperties::Property::NoPHIs);
116char BranchFolderPass::ID = 0;
121 "Control Flow Optimizer",
false,
false)
124 if (skipFunction(MF.getFunction()))
130 bool EnableTailMerge = !MF.getTarget().requiresStructuredCFG() &&
133 getAnalysis<MachineBlockFrequencyInfo>());
135 getAnalysis<MachineBranchProbabilityInfo>(),
136 &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI());
138 MF.getSubtarget().getRegisterInfo());
145 : EnableHoistCommonCode(CommonHoist), MinCommonTailLength(MinTailLength),
146 MBBFreqInfo(FreqInfo), MBPI(ProbInfo), PSI(PSI) {
147 if (MinCommonTailLength == 0)
151 EnableTailMerge = DefaultEnableTailMerge;
168 TriedMerging.erase(
MBB);
172 if (
MI.shouldUpdateCallSiteInfo())
177 EHScopeMembership.erase(
MBB);
186 if (!tii)
return false;
188 TriedMerging.clear();
191 AfterBlockPlacement = AfterPlacement;
199 MRI.invalidateLiveness();
201 bool MadeChange =
false;
206 bool MadeChangeThisIteration =
true;
207 while (MadeChangeThisIteration) {
208 MadeChangeThisIteration = TailMergeBlocks(MF);
211 if (!AfterBlockPlacement || MadeChangeThisIteration)
212 MadeChangeThisIteration |= OptimizeBranches(MF);
213 if (EnableHoistCommonCode)
214 MadeChangeThisIteration |= HoistCommonCode(MF);
215 MadeChange |= MadeChangeThisIteration;
229 if (!
Op.isJTI())
continue;
232 JTIsLive.
set(
Op.getIndex());
238 for (
unsigned i = 0, e = JTIsLive.
size(); i != e; ++i)
239 if (!JTIsLive.
test(i)) {
253 unsigned Hash =
MI.getOpcode();
254 for (
unsigned i = 0, e =
MI.getNumOperands(); i != e; ++i) {
260 unsigned OperandHash = 0;
261 switch (
Op.getType()) {
263 OperandHash =
Op.getReg();
266 OperandHash =
Op.getImm();
269 OperandHash =
Op.getMBB()->getNumber();
274 OperandHash =
Op.getIndex();
280 OperandHash =
Op.getOffset();
286 Hash += ((OperandHash << 3) |
Op.getType()) << (i & 31);
302 return !(
MI.isDebugInstr() ||
MI.isCFIInstruction());
332 unsigned TailLen = 0;
336 if (MBBI1 == MBB1->
end() || MBBI2 == MBB2->
end())
338 if (!MBBI1->isIdenticalTo(*MBBI2) ||
344 MBBI1->isInlineAsm()) {
370 }
while (
I != OldInst);
379 "Can only handle full register.");
384 BuildMI(OldMBB, OldInst,
DL, TII->
get(TargetOpcode::IMPLICIT_DEF), Reg);
412 NewMBB->
splice(NewMBB->
end(), &CurMBB, BBI1, CurMBB.
end());
417 ML->addBasicBlockToLoop(NewMBB, MLI->
getBase());
426 const auto &EHScopeI = EHScopeMembership.find(&CurMBB);
427 if (EHScopeI != EHScopeMembership.end()) {
428 auto n = EHScopeI->second;
429 EHScopeMembership[NewMBB] = n;
440 for (;
I !=
E; ++
I) {
445 else if (
I->mayLoadOrStore())
466 if (
TBB == NextBB && !
Cond.empty() && !FBB) {
479BranchFolder::MergePotentialsElt::operator<(
const MergePotentialsElt &o)
const {
480 if (getHash() <
o.getHash())
482 if (getHash() >
o.getHash())
484 if (getBlock()->getNumber() <
o.getBlock()->getNumber())
486 if (getBlock()->getNumber() >
o.getBlock()->getNumber())
497 unsigned NumTerms = 0;
504 if (!
I->isTerminator())
break;
539 unsigned MinCommonTailLength,
unsigned &CommonTailLen,
548 if (!EHScopeMembership.
empty()) {
549 auto EHScope1 = EHScopeMembership.
find(MBB1);
550 assert(EHScope1 != EHScopeMembership.
end());
551 auto EHScope2 = EHScopeMembership.
find(MBB2);
552 assert(EHScope2 != EHScopeMembership.
end());
553 if (EHScope1->second != EHScope2->second)
558 if (CommonTailLen == 0)
562 << CommonTailLen <<
'\n');
572 bool FullBlockTail1 = I1 == MBB1->
begin();
573 bool FullBlockTail2 = I2 == MBB2->
begin();
580 if ((MBB1 == PredBB || MBB2 == PredBB) &&
581 (!AfterPlacement || MBB1->
succ_size() == 1)) {
584 if (CommonTailLen > NumTerms)
593 if (FullBlockTail1 && FullBlockTail2 &&
610 if (AfterPlacement && FullBlockTail1 && FullBlockTail2) {
616 return (
MBB != &*MF->
begin()) && std::prev(
I)->canFallThrough();
618 if (!BothFallThrough(MBB1) || !BothFallThrough(MBB2))
627 unsigned EffectiveTailLen = CommonTailLen;
628 if (SuccBB && MBB1 != PredBB && MBB2 != PredBB &&
629 (MBB1->
succ_size() == 1 || !AfterPlacement) &&
635 if (EffectiveTailLen >= MinCommonTailLength)
647 return EffectiveTailLen >= 2 && OptForSize &&
648 (FullBlockTail1 || FullBlockTail2);
651unsigned BranchFolder::ComputeSameTails(
unsigned CurHash,
652 unsigned MinCommonTailLength,
655 unsigned maxCommonTailLength = 0
U;
658 MPIterator HighestMPIter = std::prev(MergePotentials.end());
659 for (MPIterator CurMPIter = std::prev(MergePotentials.end()),
660 B = MergePotentials.begin();
661 CurMPIter !=
B && CurMPIter->getHash() == CurHash; --CurMPIter) {
662 for (MPIterator
I = std::prev(CurMPIter);
I->getHash() == CurHash; --
I) {
663 unsigned CommonTailLen;
666 CommonTailLen, TrialBBI1, TrialBBI2,
669 AfterBlockPlacement, MBBFreqInfo, PSI)) {
670 if (CommonTailLen > maxCommonTailLength) {
672 maxCommonTailLength = CommonTailLen;
673 HighestMPIter = CurMPIter;
674 SameTails.push_back(SameTailElt(CurMPIter, TrialBBI1));
676 if (HighestMPIter == CurMPIter &&
677 CommonTailLen == maxCommonTailLength)
678 SameTails.push_back(SameTailElt(
I, TrialBBI2));
684 return maxCommonTailLength;
687void BranchFolder::RemoveBlocksWithHash(
unsigned CurHash,
690 MPIterator CurMPIter,
B;
691 for (CurMPIter = std::prev(MergePotentials.end()),
692 B = MergePotentials.begin();
693 CurMPIter->getHash() == CurHash; --CurMPIter) {
696 if (SuccBB && CurMBB != PredBB)
701 if (CurMPIter->getHash() != CurHash)
703 MergePotentials.erase(CurMPIter, MergePotentials.end());
708 unsigned maxCommonTailLength,
709 unsigned &commonTailIndex) {
711 unsigned TimeEstimate = ~0
U;
712 for (
unsigned i = 0, e = SameTails.size(); i != e; ++i) {
714 if (SameTails[i].getBlock() == PredBB) {
721 SameTails[i].getTailStartPos());
722 if (t <= TimeEstimate) {
729 SameTails[commonTailIndex].getTailStartPos();
733 << maxCommonTailLength);
746 SameTails[commonTailIndex].setBlock(newMBB);
747 SameTails[commonTailIndex].setTailStartPos(newMBB->
begin());
763 unsigned CommonTailLen = 0;
764 for (
auto E =
MBB->
end(); MBBIStartPos !=
E; ++MBBIStartPos)
772 while (CommonTailLen--) {
773 assert(
MBBI != MBBIE &&
"Reached BB end within common tail length!");
784 assert(MBBICommon != MBBIECommon &&
785 "Reached BB end within common tail length!");
786 assert(MBBICommon->isIdenticalTo(*
MBBI) &&
"Expected matching MIIs!");
789 if (MBBICommon->mayLoadOrStore())
790 MBBICommon->cloneMergedMemRefs(*
MBB->
getParent(), {&*MBBICommon, &*MBBI});
792 for (
unsigned I = 0,
E = MBBICommon->getNumOperands();
I !=
E; ++
I) {
806void BranchFolder::mergeCommonTails(
unsigned commonTailIndex) {
809 std::vector<MachineBasicBlock::iterator> NextCommonInsts(SameTails.size());
810 for (
unsigned int i = 0 ; i != SameTails.size() ; ++i) {
811 if (i != commonTailIndex) {
812 NextCommonInsts[i] = SameTails[i].getTailStartPos();
816 "MBB is not a common tail only block");
820 for (
auto &
MI : *
MBB) {
824 for (
unsigned int i = 0 ; i < NextCommonInsts.size() ; i++) {
825 if (i == commonTailIndex)
828 auto &Pos = NextCommonInsts[i];
829 assert(Pos != SameTails[i].getBlock()->
end() &&
830 "Reached BB end within common tail");
833 assert(Pos != SameTails[i].getBlock()->
end() &&
834 "Reached BB end within common tail");
836 assert(
MI.isIdenticalTo(*Pos) &&
"Expected matching MIIs!");
838 NextCommonInsts[i] = ++Pos;
861 return NewLiveIns.contains(SReg) && !MRI->isReserved(SReg);
866 BuildMI(*Pred, InsertBefore,
DL, TII->
get(TargetOpcode::IMPLICIT_DEF),
887 unsigned MinCommonTailLength) {
888 bool MadeChange =
false;
891 dbgs() <<
"\nTryTailMergeBlocks: ";
892 for (
unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
dbgs()
894 << (i == e - 1 ?
"" :
", ");
895 dbgs() <<
"\n";
if (SuccBB) {
898 dbgs() <<
" which has fall-through from "
900 }
dbgs() <<
"Looking for common tails of at least "
901 << MinCommonTailLength <<
" instruction"
902 << (MinCommonTailLength == 1 ?
"" :
"s") <<
'\n';);
909 while (MergePotentials.size() > 1) {
910 unsigned CurHash = MergePotentials.back().getHash();
914 unsigned maxCommonTailLength = ComputeSameTails(CurHash,
920 if (SameTails.empty()) {
921 RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
930 &MergePotentials.front().getBlock()->getParent()->front();
931 unsigned commonTailIndex = SameTails.size();
934 if (SameTails.size() == 2 &&
935 SameTails[0].getBlock()->isLayoutSuccessor(SameTails[1].getBlock()) &&
936 SameTails[1].tailIsWholeBlock() && !SameTails[1].getBlock()->isEHPad())
938 else if (SameTails.size() == 2 &&
939 SameTails[1].getBlock()->isLayoutSuccessor(
940 SameTails[0].getBlock()) &&
941 SameTails[0].tailIsWholeBlock() &&
942 !SameTails[0].getBlock()->isEHPad())
947 for (
unsigned i = 0, e = SameTails.size(); i != e; ++i) {
950 SameTails[i].tailIsWholeBlock())
956 if (SameTails[i].tailIsWholeBlock())
961 if (commonTailIndex == SameTails.size() ||
962 (SameTails[commonTailIndex].getBlock() == PredBB &&
963 !SameTails[commonTailIndex].tailIsWholeBlock())) {
966 if (!CreateCommonTailOnlyBlock(PredBB, SuccBB,
967 maxCommonTailLength, commonTailIndex)) {
968 RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
976 setCommonTailEdgeWeights(*
MBB);
980 mergeCommonTails(commonTailIndex);
986 for (
unsigned int i=0, e = SameTails.size(); i != e; ++i) {
987 if (commonTailIndex == i)
990 << (i == e - 1 ?
"" :
", "));
992 replaceTailWithBranchTo(SameTails[i].getTailStartPos(), *
MBB);
994 MergePotentials.erase(SameTails[i].getMPIter());
1005 bool MadeChange =
false;
1006 if (!EnableTailMerge)
1011 MergePotentials.clear();
1022 for (
const MergePotentialsElt &Elt : MergePotentials)
1023 TriedMerging.insert(Elt.getBlock());
1026 if (MergePotentials.size() >= 2)
1027 MadeChange |= TryTailMergeBlocks(
nullptr,
nullptr, MinCommonTailLength);
1050 if (
I->pred_size() < 2)
continue;
1054 MergePotentials.clear();
1067 if (AfterBlockPlacement && MLI) {
1069 if (
ML && IBB ==
ML->getHeader())
1077 if (TriedMerging.count(PBB))
1085 if (!UniquePreds.
insert(PBB).second)
1090 if (PBB->hasEHPadSuccessor() || PBB->mayHaveInlineAsmBr())
1096 if (AfterBlockPlacement && MLI)
1106 if (!
Cond.empty() &&
TBB == IBB) {
1111 auto Next = ++PBB->getIterator();
1112 if (Next != MF.end())
1118 if (
TBB && (
Cond.empty() || FBB)) {
1119 DebugLoc dl = PBB->findBranchDebugLoc();
1127 MergePotentials.push_back(MergePotentialsElt(
HashEndOfMBB(*PBB), PBB));
1134 for (MergePotentialsElt &Elt : MergePotentials)
1135 TriedMerging.insert(Elt.getBlock());
1137 if (MergePotentials.size() >= 2)
1138 MadeChange |= TryTailMergeBlocks(IBB, PredBB, MinCommonTailLength);
1142 PredBB = &*std::prev(
I);
1143 if (MergePotentials.size() == 1 &&
1144 MergePotentials.begin()->getBlock() != PredBB)
1145 FixTail(MergePotentials.begin()->getBlock(), IBB, TII);
1158 for (
const auto &Src : SameTails) {
1161 AccumulatedMBBFreq += BlockFreq;
1168 auto EdgeFreq = EdgeFreqLs.begin();
1171 SuccI != SuccE; ++SuccI, ++EdgeFreq)
1175 MBBFreqInfo.
setBlockFreq(&TailMBB, AccumulatedMBBFreq);
1181 std::accumulate(EdgeFreqLs.begin(), EdgeFreqLs.end(),
BlockFrequency(0))
1183 auto EdgeFreq = EdgeFreqLs.begin();
1185 if (SumEdgeFreq > 0) {
1187 SuccI != SuccE; ++SuccI, ++EdgeFreq) {
1189 EdgeFreq->getFrequency(), SumEdgeFreq);
1200 bool MadeChange =
false;
1209 MadeChange |= OptimizeBlock(&
MBB);
1213 RemoveDeadBlock(&
MBB);
1233 return I->isBranch();
1242 assert(MBB1 && MBB2 &&
"Unknown MachineBasicBlock");
1250 if (MBB1I == MBB1->
end() || MBB2I == MBB2->
end())
1258 return MBB2I->isCall() && !MBB1I->isCall();
1265 if (
I !=
MBB.
end() &&
I->isBranch())
1266 return I->getDebugLoc();
1275 if (
MI.isDebugInstr()) {
1276 TII->duplicate(PredMBB, InsertBefore,
MI);
1277 LLVM_DEBUG(
dbgs() <<
"Copied debug entity from empty block to pred: "
1287 if (
MI.isDebugInstr()) {
1288 TII->duplicate(SuccMBB, InsertBefore,
MI);
1289 LLVM_DEBUG(
dbgs() <<
"Copied debug entity from empty block to succ: "
1318 bool MadeChange =
false;
1326 bool SameEHScope =
true;
1327 if (!EHScopeMembership.empty() && FallThrough != MF.
end()) {
1328 auto MBBEHScope = EHScopeMembership.find(
MBB);
1329 assert(MBBEHScope != EHScopeMembership.end());
1330 auto FallThroughEHScope = EHScopeMembership.find(&*FallThrough);
1331 assert(FallThroughEHScope != EHScopeMembership.end());
1332 SameEHScope = MBBEHScope->second == FallThroughEHScope->second;
1339 bool CurUnAnalyzable =
1352 if (FallThrough == MF.
end()) {
1354 }
else if (FallThrough->isEHPad()) {
1369 MJTI->ReplaceMBBInJumpTables(
MBB, &*FallThrough);
1381 bool PriorUnAnalyzable =
1382 TII->
analyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond,
true);
1383 if (!PriorUnAnalyzable) {
1387 if (PriorTBB && PriorTBB == PriorFBB) {
1391 if (PriorTBB !=
MBB)
1392 TII->
insertBranch(PrevBB, PriorTBB,
nullptr, PriorCond, dl);
1395 goto ReoptimizeBlock;
1409 <<
"From MBB: " << *
MBB);
1411 if (!PrevBB.
empty()) {
1417 while (PrevBBIter != PrevBB.
begin() && MBBIter !=
MBB->
end()
1418 && PrevBBIter->isDebugInstr() && MBBIter->isDebugInstr()) {
1419 if (!MBBIter->isIdenticalTo(*PrevBBIter))
1422 ++MBBIter; -- PrevBBIter;
1436 if (PriorTBB ==
MBB && !PriorFBB) {
1440 goto ReoptimizeBlock;
1445 if (PriorFBB ==
MBB) {
1448 TII->
insertBranch(PrevBB, PriorTBB,
nullptr, PriorCond, dl);
1451 goto ReoptimizeBlock;
1457 if (PriorTBB ==
MBB) {
1462 TII->
insertBranch(PrevBB, PriorFBB,
nullptr, NewPriorCond, dl);
1465 goto ReoptimizeBlock;
1480 bool DoTransform =
true;
1487 if (FallThrough == --MF.
end() &&
1489 DoTransform =
false;
1496 <<
"To make fallthrough to: " << *PriorTBB <<
"\n");
1519 bool PredAnalyzable =
1520 !TII->
analyzeBranch(*Pred, PredTBB, PredFBB, PredCond,
true);
1523 if (PredAnalyzable && !PredCond.
empty() && PredTBB ==
MBB &&
1524 PredTBB != PredFBB) {
1542 if (!PredsChanged.
empty()) {
1543 NumTailCalls += PredsChanged.
size();
1544 for (
auto &Pred : PredsChanged)
1552 if (!CurUnAnalyzable) {
1558 if (CurTBB && CurFBB && CurFBB ==
MBB && CurTBB !=
MBB) {
1566 goto ReoptimizeBlock;
1572 if (CurTBB && CurCond.
empty() && !CurFBB &&
1595 if (PredHasNoFallThrough || !PriorUnAnalyzable ||
1600 PriorTBB !=
MBB && PriorFBB !=
MBB) {
1603 "Bad branch analysis");
1606 assert(!PriorFBB &&
"Machine CFG out of date!");
1611 TII->
insertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl);
1616 bool DidChange =
false;
1617 bool HasBranchToSelf =
false;
1623 HasBranchToSelf =
true;
1633 *PMBB, NewCurTBB, NewCurFBB, NewCurCond,
true);
1634 if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
1638 TII->
insertBranch(*PMBB, NewCurTBB,
nullptr, NewCurCond, pdl);
1647 MJTI->ReplaceMBBInJumpTables(
MBB, CurTBB);
1651 if (!HasBranchToSelf)
return MadeChange;
1678 !TII->
analyzeBranch(*PredBB, PredTBB, PredFBB, PredCond,
true) &&
1679 (PredTBB ==
MBB || PredFBB ==
MBB) &&
1680 (!CurFallsThru || !CurTBB || !CurFBB) &&
1699 goto ReoptimizeBlock;
1704 if (!CurFallsThru) {
1707 if (!CurUnAnalyzable) {
1717 if (SuccBB !=
MBB && &*SuccPrev !=
MBB &&
1718 !SuccPrev->canFallThrough()) {
1721 goto ReoptimizeBlock;
1742 if (FallThrough != MF.
end() &&
1743 !FallThrough->isEHPad() &&
1744 !TII->
analyzeBranch(PrevBB, PrevTBB, PrevFBB, PrevCond,
true) &&
1761 bool MadeChange =
false;
1763 MadeChange |= HoistCommonCodeInSuccs(&
MBB);
1773 if (SuccBB != TrueBB)
1778template <
class Container>
1781 if (Reg.isPhysical()) {
1803 if (!
TII->isUnpredicatedTerminator(*Loc))
1844 if (!MO.isReg() || MO.isUse())
1849 if (
Uses.count(Reg)) {
1865 bool DontMoveAcrossStore =
true;
1866 if (!PI->isSafeToMove(
nullptr, DontMoveAcrossStore) ||
TII->
isPredicated(*PI))
1880 if (
Uses.erase(Reg)) {
1881 if (Reg.isPhysical()) {
1918 bool HasDups =
false;
1924 while (TIB != TIE && FIB != FIE) {
1928 if (TIB == TIE || FIB == FIE)
1941 if (MO.isRegMask()) {
1951 if (
Uses.count(Reg)) {
1958 if (Defs.
count(Reg) && !MO.isDead()) {
1973 }
else if (!ActiveDefsSet.
count(Reg)) {
1974 if (Defs.
count(Reg)) {
1980 if (MO.isKill() &&
Uses.count(Reg))
1983 MO.setIsKill(
false);
1989 bool DontMoveAcrossStore =
true;
1990 if (!TIB->isSafeToMove(
nullptr, DontMoveAcrossStore))
2000 if (!AllDefsSet.
count(Reg)) {
2003 if (
Reg.isPhysical()) {
2005 ActiveDefsSet.
erase(*AI);
2007 ActiveDefsSet.
erase(Reg);
2016 if (!Reg ||
Reg.isVirtual())
2031 FBB->erase(FBB->begin(), FIB);
2033 if (UpdateLiveIns) {
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 FixTail(MachineBasicBlock *CurMBB, MachineBasicBlock *SuccBB, const TargetInstrInfo *TII)
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 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")
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
Rewrite Partial Register Uses
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
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)
bool hasOptSize() const
Optimize this function for size (-Os) or minimum size (-Oz).
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.
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 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)
MachineBlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to estimate machine basic b...
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.
Function & getFunction()
Return the LLVM function that this machine code represents.
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
LoopInfoBase< MachineBasicBlock, MachineLoop > & getBase()
void removeBlock(MachineBasicBlock *BB)
This method completely removes BB from all data structures, including all of the Loop objects it is n...
MachineLoop * getLoopFor(const MachineBasicBlock *BB) const
Return the innermost loop that BB lives in.
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 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...
static void recomputeLiveIns(MachineBasicBlock &MBB)
Convenience function for recomputing live-in's for MBB.
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.
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.