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())
490#ifndef _GLIBCXX_DEBUG
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)
653 return EffectiveTailLen >= 2 && OptForSize &&
654 (FullBlockTail1 || FullBlockTail2);
657unsigned BranchFolder::ComputeSameTails(
unsigned CurHash,
658 unsigned MinCommonTailLength,
661 unsigned maxCommonTailLength = 0
U;
664 MPIterator HighestMPIter = std::prev(MergePotentials.end());
665 for (MPIterator CurMPIter = std::prev(MergePotentials.end()),
666 B = MergePotentials.begin();
667 CurMPIter !=
B && CurMPIter->getHash() == CurHash; --CurMPIter) {
668 for (MPIterator
I = std::prev(CurMPIter);
I->getHash() == CurHash; --
I) {
669 unsigned CommonTailLen;
672 CommonTailLen, TrialBBI1, TrialBBI2,
675 AfterBlockPlacement, MBBFreqInfo, PSI)) {
676 if (CommonTailLen > maxCommonTailLength) {
678 maxCommonTailLength = CommonTailLen;
679 HighestMPIter = CurMPIter;
680 SameTails.push_back(SameTailElt(CurMPIter, TrialBBI1));
682 if (HighestMPIter == CurMPIter &&
683 CommonTailLen == maxCommonTailLength)
684 SameTails.push_back(SameTailElt(
I, TrialBBI2));
690 return maxCommonTailLength;
693void BranchFolder::RemoveBlocksWithHash(
unsigned CurHash,
696 MPIterator CurMPIter,
B;
697 for (CurMPIter = std::prev(MergePotentials.end()),
698 B = MergePotentials.begin();
699 CurMPIter->getHash() == CurHash; --CurMPIter) {
702 if (SuccBB && CurMBB != PredBB)
707 if (CurMPIter->getHash() != CurHash)
709 MergePotentials.erase(CurMPIter, MergePotentials.end());
714 unsigned maxCommonTailLength,
715 unsigned &commonTailIndex) {
717 unsigned TimeEstimate = ~0
U;
718 for (
unsigned i = 0, e = SameTails.size(); i != e; ++i) {
720 if (SameTails[i].getBlock() == PredBB) {
727 SameTails[i].getTailStartPos());
728 if (t <= TimeEstimate) {
735 SameTails[commonTailIndex].getTailStartPos();
739 << maxCommonTailLength);
752 SameTails[commonTailIndex].setBlock(newMBB);
753 SameTails[commonTailIndex].setTailStartPos(newMBB->
begin());
769 unsigned CommonTailLen = 0;
770 for (
auto E =
MBB->
end(); MBBIStartPos !=
E; ++MBBIStartPos)
778 while (CommonTailLen--) {
779 assert(
MBBI != MBBIE &&
"Reached BB end within common tail length!");
790 assert(MBBICommon != MBBIECommon &&
791 "Reached BB end within common tail length!");
792 assert(MBBICommon->isIdenticalTo(*
MBBI) &&
"Expected matching MIIs!");
795 if (MBBICommon->mayLoadOrStore())
796 MBBICommon->cloneMergedMemRefs(*
MBB->
getParent(), {&*MBBICommon, &*MBBI});
798 for (
unsigned I = 0,
E = MBBICommon->getNumOperands();
I !=
E; ++
I) {
812void BranchFolder::mergeCommonTails(
unsigned commonTailIndex) {
815 std::vector<MachineBasicBlock::iterator> NextCommonInsts(SameTails.size());
816 for (
unsigned int i = 0 ; i != SameTails.size() ; ++i) {
817 if (i != commonTailIndex) {
818 NextCommonInsts[i] = SameTails[i].getTailStartPos();
822 "MBB is not a common tail only block");
826 for (
auto &
MI : *
MBB) {
830 for (
unsigned int i = 0 ; i < NextCommonInsts.size() ; i++) {
831 if (i == commonTailIndex)
834 auto &Pos = NextCommonInsts[i];
835 assert(Pos != SameTails[i].getBlock()->
end() &&
836 "Reached BB end within common tail");
839 assert(Pos != SameTails[i].getBlock()->
end() &&
840 "Reached BB end within common tail");
842 assert(
MI.isIdenticalTo(*Pos) &&
"Expected matching MIIs!");
844 NextCommonInsts[i] = ++Pos;
864 BuildMI(*Pred, InsertBefore,
DL, TII->
get(TargetOpcode::IMPLICIT_DEF),
885 unsigned MinCommonTailLength) {
886 bool MadeChange =
false;
889 dbgs() <<
"\nTryTailMergeBlocks: ";
890 for (
unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
dbgs()
892 << (i == e - 1 ?
"" :
", ");
893 dbgs() <<
"\n";
if (SuccBB) {
896 dbgs() <<
" which has fall-through from "
898 }
dbgs() <<
"Looking for common tails of at least "
899 << MinCommonTailLength <<
" instruction"
900 << (MinCommonTailLength == 1 ?
"" :
"s") <<
'\n';);
907 while (MergePotentials.size() > 1) {
908 unsigned CurHash = MergePotentials.back().getHash();
912 unsigned maxCommonTailLength = ComputeSameTails(CurHash,
918 if (SameTails.empty()) {
919 RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
928 &MergePotentials.front().getBlock()->getParent()->front();
929 unsigned commonTailIndex = SameTails.size();
932 if (SameTails.size() == 2 &&
933 SameTails[0].getBlock()->isLayoutSuccessor(SameTails[1].getBlock()) &&
934 SameTails[1].tailIsWholeBlock() && !SameTails[1].getBlock()->isEHPad())
936 else if (SameTails.size() == 2 &&
937 SameTails[1].getBlock()->isLayoutSuccessor(
938 SameTails[0].getBlock()) &&
939 SameTails[0].tailIsWholeBlock() &&
940 !SameTails[0].getBlock()->isEHPad())
945 for (
unsigned i = 0, e = SameTails.size(); i != e; ++i) {
948 SameTails[i].tailIsWholeBlock())
954 if (SameTails[i].tailIsWholeBlock())
959 if (commonTailIndex == SameTails.size() ||
960 (SameTails[commonTailIndex].getBlock() == PredBB &&
961 !SameTails[commonTailIndex].tailIsWholeBlock())) {
964 if (!CreateCommonTailOnlyBlock(PredBB, SuccBB,
965 maxCommonTailLength, commonTailIndex)) {
966 RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
974 setCommonTailEdgeWeights(*
MBB);
978 mergeCommonTails(commonTailIndex);
984 for (
unsigned int i=0, e = SameTails.size(); i != e; ++i) {
985 if (commonTailIndex == i)
988 << (i == e - 1 ?
"" :
", "));
990 replaceTailWithBranchTo(SameTails[i].getTailStartPos(), *
MBB);
992 MergePotentials.erase(SameTails[i].getMPIter());
1003 bool MadeChange =
false;
1004 if (!EnableTailMerge)
1009 MergePotentials.clear();
1020 for (
const MergePotentialsElt &Elt : MergePotentials)
1021 TriedMerging.insert(Elt.getBlock());
1024 if (MergePotentials.size() >= 2)
1025 MadeChange |= TryTailMergeBlocks(
nullptr,
nullptr, MinCommonTailLength);
1048 if (
I->pred_size() < 2)
continue;
1052 MergePotentials.clear();
1065 if (AfterBlockPlacement && MLI) {
1067 if (
ML && IBB ==
ML->getHeader())
1075 if (TriedMerging.count(PBB))
1083 if (!UniquePreds.
insert(PBB).second)
1088 if (PBB->hasEHPadSuccessor() || PBB->mayHaveInlineAsmBr())
1094 if (AfterBlockPlacement && MLI)
1104 if (!
Cond.empty() &&
TBB == IBB) {
1109 auto Next = ++PBB->getIterator();
1110 if (Next != MF.end())
1116 if (
TBB && (
Cond.empty() || FBB)) {
1117 DebugLoc dl = PBB->findBranchDebugLoc();
1125 MergePotentials.push_back(MergePotentialsElt(
HashEndOfMBB(*PBB), PBB));
1132 for (MergePotentialsElt &Elt : MergePotentials)
1133 TriedMerging.insert(Elt.getBlock());
1135 if (MergePotentials.size() >= 2)
1136 MadeChange |= TryTailMergeBlocks(IBB, PredBB, MinCommonTailLength);
1140 PredBB = &*std::prev(
I);
1141 if (MergePotentials.size() == 1 &&
1142 MergePotentials.begin()->getBlock() != PredBB)
1143 FixTail(MergePotentials.begin()->getBlock(), IBB, TII);
1156 for (
const auto &Src : SameTails) {
1159 AccumulatedMBBFreq += BlockFreq;
1166 auto EdgeFreq = EdgeFreqLs.begin();
1169 SuccI != SuccE; ++SuccI, ++EdgeFreq)
1173 MBBFreqInfo.
setBlockFreq(&TailMBB, AccumulatedMBBFreq);
1179 std::accumulate(EdgeFreqLs.begin(), EdgeFreqLs.end(),
BlockFrequency(0))
1181 auto EdgeFreq = EdgeFreqLs.begin();
1183 if (SumEdgeFreq > 0) {
1185 SuccI != SuccE; ++SuccI, ++EdgeFreq) {
1187 EdgeFreq->getFrequency(), SumEdgeFreq);
1198 bool MadeChange =
false;
1207 MadeChange |= OptimizeBlock(&
MBB);
1211 RemoveDeadBlock(&
MBB);
1231 return I->isBranch();
1240 assert(MBB1 && MBB2 &&
"Unknown MachineBasicBlock");
1248 if (MBB1I == MBB1->
end() || MBB2I == MBB2->
end())
1256 return MBB2I->isCall() && !MBB1I->isCall();
1263 if (
I !=
MBB.
end() &&
I->isBranch())
1264 return I->getDebugLoc();
1273 if (
MI.isDebugInstr()) {
1274 TII->duplicate(PredMBB, InsertBefore,
MI);
1275 LLVM_DEBUG(
dbgs() <<
"Copied debug entity from empty block to pred: "
1285 if (
MI.isDebugInstr()) {
1286 TII->duplicate(SuccMBB, InsertBefore,
MI);
1287 LLVM_DEBUG(
dbgs() <<
"Copied debug entity from empty block to succ: "
1316 bool MadeChange =
false;
1324 bool SameEHScope =
true;
1325 if (!EHScopeMembership.empty() && FallThrough != MF.
end()) {
1326 auto MBBEHScope = EHScopeMembership.find(
MBB);
1327 assert(MBBEHScope != EHScopeMembership.end());
1328 auto FallThroughEHScope = EHScopeMembership.find(&*FallThrough);
1329 assert(FallThroughEHScope != EHScopeMembership.end());
1330 SameEHScope = MBBEHScope->second == FallThroughEHScope->second;
1337 bool CurUnAnalyzable =
1350 if (FallThrough == MF.
end()) {
1352 }
else if (FallThrough->isEHPad()) {
1367 MJTI->ReplaceMBBInJumpTables(
MBB, &*FallThrough);
1379 bool PriorUnAnalyzable =
1380 TII->
analyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond,
true);
1381 if (!PriorUnAnalyzable) {
1385 if (PriorTBB && PriorTBB == PriorFBB) {
1389 if (PriorTBB !=
MBB)
1390 TII->
insertBranch(PrevBB, PriorTBB,
nullptr, PriorCond, dl);
1393 goto ReoptimizeBlock;
1407 <<
"From MBB: " << *
MBB);
1409 if (!PrevBB.
empty()) {
1415 while (PrevBBIter != PrevBB.
begin() && MBBIter !=
MBB->
end()
1416 && PrevBBIter->isDebugInstr() && MBBIter->isDebugInstr()) {
1417 if (!MBBIter->isIdenticalTo(*PrevBBIter))
1420 ++MBBIter; -- PrevBBIter;
1434 if (PriorTBB ==
MBB && !PriorFBB) {
1438 goto ReoptimizeBlock;
1443 if (PriorFBB ==
MBB) {
1446 TII->
insertBranch(PrevBB, PriorTBB,
nullptr, PriorCond, dl);
1449 goto ReoptimizeBlock;
1455 if (PriorTBB ==
MBB) {
1460 TII->
insertBranch(PrevBB, PriorFBB,
nullptr, NewPriorCond, dl);
1463 goto ReoptimizeBlock;
1478 bool DoTransform =
true;
1485 if (FallThrough == --MF.
end() &&
1487 DoTransform =
false;
1494 <<
"To make fallthrough to: " << *PriorTBB <<
"\n");
1517 bool PredAnalyzable =
1518 !TII->
analyzeBranch(*Pred, PredTBB, PredFBB, PredCond,
true);
1521 if (PredAnalyzable && !PredCond.
empty() && PredTBB ==
MBB &&
1522 PredTBB != PredFBB) {
1540 if (!PredsChanged.
empty()) {
1541 NumTailCalls += PredsChanged.
size();
1542 for (
auto &Pred : PredsChanged)
1550 if (!CurUnAnalyzable) {
1556 if (CurTBB && CurFBB && CurFBB ==
MBB && CurTBB !=
MBB) {
1564 goto ReoptimizeBlock;
1570 if (CurTBB && CurCond.
empty() && !CurFBB &&
1593 if (PredHasNoFallThrough || !PriorUnAnalyzable ||
1598 PriorTBB !=
MBB && PriorFBB !=
MBB) {
1601 "Bad branch analysis");
1604 assert(!PriorFBB &&
"Machine CFG out of date!");
1609 TII->
insertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl);
1614 bool DidChange =
false;
1615 bool HasBranchToSelf =
false;
1621 HasBranchToSelf =
true;
1631 *PMBB, NewCurTBB, NewCurFBB, NewCurCond,
true);
1632 if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
1636 TII->
insertBranch(*PMBB, NewCurTBB,
nullptr, NewCurCond, pdl);
1645 MJTI->ReplaceMBBInJumpTables(
MBB, CurTBB);
1649 if (!HasBranchToSelf)
return MadeChange;
1676 !TII->
analyzeBranch(*PredBB, PredTBB, PredFBB, PredCond,
true) &&
1677 (PredTBB ==
MBB || PredFBB ==
MBB) &&
1678 (!CurFallsThru || !CurTBB || !CurFBB) &&
1697 goto ReoptimizeBlock;
1702 if (!CurFallsThru) {
1705 if (!CurUnAnalyzable) {
1715 if (SuccBB !=
MBB && &*SuccPrev !=
MBB &&
1716 !SuccPrev->canFallThrough()) {
1719 goto ReoptimizeBlock;
1740 if (FallThrough != MF.
end() &&
1741 !FallThrough->isEHPad() &&
1742 !TII->
analyzeBranch(PrevBB, PrevTBB, PrevFBB, PrevCond,
true) &&
1759 bool MadeChange =
false;
1761 MadeChange |= HoistCommonCodeInSuccs(&
MBB);
1771 if (SuccBB != TrueBB)
1776template <
class Container>
1779 if (Reg.isPhysical()) {
1801 if (!
TII->isUnpredicatedTerminator(*Loc))
1842 if (!MO.isReg() || MO.isUse())
1847 if (
Uses.count(Reg)) {
1863 bool DontMoveAcrossStore =
true;
1864 if (!PI->isSafeToMove(
nullptr, DontMoveAcrossStore) ||
TII->
isPredicated(*PI))
1878 if (
Uses.erase(Reg)) {
1879 if (Reg.isPhysical()) {
1881 Uses.erase(*SubRegs);
1916 bool HasDups =
false;
1922 while (TIB != TIE && FIB != FIE) {
1926 if (TIB == TIE || FIB == FIE)
1939 if (MO.isRegMask()) {
1949 if (
Uses.count(Reg)) {
1956 if (Defs.
count(Reg) && !MO.isDead()) {
1971 }
else if (!ActiveDefsSet.
count(Reg)) {
1972 if (Defs.
count(Reg)) {
1978 if (MO.isKill() &&
Uses.count(Reg))
1981 MO.setIsKill(
false);
1987 bool DontMoveAcrossStore =
true;
1988 if (!TIB->isSafeToMove(
nullptr, DontMoveAcrossStore))
1993 if (!MO.isReg() || !MO.isUse() || !MO.isKill())
1998 if (!AllDefsSet.
count(Reg)) {
2001 if (
Reg.isPhysical()) {
2003 ActiveDefsSet.
erase(*AI);
2005 ActiveDefsSet.
erase(Reg);
2011 if (!MO.isReg() || !MO.isDef() || MO.isDead())
2014 if (!Reg ||
Reg.isVirtual())
2029 FBB->erase(FBB->begin(), FIB);
2031 if (UpdateLiveIns) {
unsigned const MachineRegisterInfo * MRI
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
MachineBasicBlock MachineBasicBlock::iterator MBBI
SmallPtrSet< MachineInstr *, 2 > Uses
SmallVector< MachineOperand, 4 > Cond
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")
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
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 const DILocation * getMergedLocation(const DILocation *LocA, const DILocation *LocB)
When two instructions are combined into a single instruction we also need to combine the original loc...
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.
bool isValid() const
isValid - returns true if this iterator is not yet at the end.
MCSubRegIterator enumerates all sub-registers of 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 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)
MachineBasicBlock * CreateMachineBasicBlock(const BasicBlock *bb=nullptr)
CreateMachineBasicBlock - Allocate a new MachineBasicBlock.
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.
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()
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
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.
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.