//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pre-alloc-split"
+#include "VirtRegMap.h"
+#include "llvm/CodeGen/CalcSpillWeights.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/LiveStackAnalysis.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
static cl::opt<int> PreSplitLimit("pre-split-limit", cl::init(-1), cl::Hidden);
+static cl::opt<int> DeadSplitLimit("dead-split-limit", cl::init(-1),
+ cl::Hidden);
+static cl::opt<int> RestoreFoldLimit("restore-fold-limit", cl::init(-1),
+ cl::Hidden);
STATISTIC(NumSplits, "Number of intervals split");
STATISTIC(NumRemats, "Number of intervals split by rematerialization");
STATISTIC(NumFolds, "Number of intervals split with spill folding");
+STATISTIC(NumRestoreFolds, "Number of intervals split with restore folding");
STATISTIC(NumRenumbers, "Number of intervals renumbered into new registers");
STATISTIC(NumDeadSpills, "Number of dead spills removed");
namespace {
- class VISIBILITY_HIDDEN PreAllocSplitting : public MachineFunctionPass {
+ class PreAllocSplitting : public MachineFunctionPass {
MachineFunction *CurrMF;
const TargetMachine *TM;
const TargetInstrInfo *TII;
+ const TargetRegisterInfo* TRI;
MachineFrameInfo *MFI;
MachineRegisterInfo *MRI;
+ SlotIndexes *SIs;
LiveIntervals *LIs;
LiveStacks *LSs;
+ VirtRegMap *VRM;
// Barrier - Current barrier being processed.
MachineInstr *Barrier;
MachineBasicBlock *BarrierMBB;
// Barrier - Current barrier index.
- unsigned BarrierIdx;
+ SlotIndex BarrierIdx;
// CurrLI - Current live interval being split.
LiveInterval *CurrLI;
DenseMap<unsigned, int> IntervalSSMap;
// Def2SpillMap - A map from a def instruction index to spill index.
- DenseMap<unsigned, unsigned> Def2SpillMap;
+ DenseMap<SlotIndex, SlotIndex> Def2SpillMap;
public:
static char ID;
- PreAllocSplitting() : MachineFunctionPass(&ID) {}
+ PreAllocSplitting()
+ : MachineFunctionPass(&ID) {}
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ AU.addRequired<SlotIndexes>();
+ AU.addPreserved<SlotIndexes>();
AU.addRequired<LiveIntervals>();
AU.addPreserved<LiveIntervals>();
AU.addRequired<LiveStacks>();
AU.addPreserved<LiveStacks>();
AU.addPreserved<RegisterCoalescer>();
+ AU.addPreserved<CalculateSpillWeights>();
if (StrongPHIElim)
AU.addPreservedID(StrongPHIEliminationID);
else
AU.addPreservedID(PHIEliminationID);
AU.addRequired<MachineDominatorTree>();
AU.addRequired<MachineLoopInfo>();
+ AU.addRequired<VirtRegMap>();
AU.addPreserved<MachineDominatorTree>();
AU.addPreserved<MachineLoopInfo>();
+ AU.addPreserved<VirtRegMap>();
MachineFunctionPass::getAnalysisUsage(AU);
}
}
/// print - Implement the dump method.
- virtual void print(std::ostream &O, const Module* M = 0) const {
+ virtual void print(raw_ostream &O, const Module* M = 0) const {
LIs->print(O, M);
}
- void print(std::ostream *O, const Module* M = 0) const {
- if (O) print(*O, M);
- }
private:
- MachineBasicBlock::iterator
- findNextEmptySlot(MachineBasicBlock*, MachineInstr*,
- unsigned&);
MachineBasicBlock::iterator
findSpillPoint(MachineBasicBlock*, MachineInstr*, MachineInstr*,
- SmallPtrSet<MachineInstr*, 4>&, unsigned&);
+ SmallPtrSet<MachineInstr*, 4>&);
MachineBasicBlock::iterator
- findRestorePoint(MachineBasicBlock*, MachineInstr*, unsigned,
- SmallPtrSet<MachineInstr*, 4>&, unsigned&);
+ findRestorePoint(MachineBasicBlock*, MachineInstr*, SlotIndex,
+ SmallPtrSet<MachineInstr*, 4>&);
int CreateSpillStackSlot(unsigned, const TargetRegisterClass *);
- bool IsAvailableInStack(MachineBasicBlock*, unsigned, unsigned, unsigned,
- unsigned&, int&) const;
-
- void UpdateSpillSlotInterval(VNInfo*, unsigned, unsigned);
-
- VNInfo* UpdateRegisterInterval(VNInfo*, unsigned, unsigned);
-
- bool ShrinkWrapToLastUse(MachineBasicBlock*, VNInfo*,
- SmallVector<MachineOperand*, 4>&,
- SmallPtrSet<MachineInstr*, 4>&);
+ bool IsAvailableInStack(MachineBasicBlock*, unsigned,
+ SlotIndex, SlotIndex,
+ SlotIndex&, int&) const;
- void ShrinkWrapLiveInterval(VNInfo*, MachineBasicBlock*, MachineBasicBlock*,
- MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*, 8>&,
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >&,
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >&,
- SmallVector<MachineBasicBlock*, 4>&);
+ void UpdateSpillSlotInterval(VNInfo*, SlotIndex, SlotIndex);
bool SplitRegLiveInterval(LiveInterval*);
bool SplitRegLiveIntervals(const TargetRegisterClass **,
SmallPtrSet<LiveInterval*, 8>&);
- void RepairLiveInterval(LiveInterval* CurrLI, VNInfo* ValNo,
- MachineInstr* DefMI, unsigned RestoreIdx);
-
bool createsNewJoin(LiveRange* LR, MachineBasicBlock* DefMBB,
MachineBasicBlock* BarrierMBB);
bool Rematerialize(unsigned vreg, VNInfo* ValNo,
MachineInstr* DefMI,
MachineBasicBlock::iterator RestorePt,
- unsigned RestoreIdx,
SmallPtrSet<MachineInstr*, 4>& RefsInMBB);
MachineInstr* FoldSpill(unsigned vreg, const TargetRegisterClass* RC,
MachineInstr* DefMI,
MachineBasicBlock* MBB,
int& SS,
SmallPtrSet<MachineInstr*, 4>& RefsInMBB);
+ MachineInstr* FoldRestore(unsigned vreg,
+ const TargetRegisterClass* RC,
+ MachineInstr* Barrier,
+ MachineBasicBlock* MBB,
+ int SS,
+ SmallPtrSet<MachineInstr*, 4>& RefsInMBB);
void RenumberValno(VNInfo* VN);
void ReconstructLiveInterval(LiveInterval* LI);
bool removeDeadSpills(SmallPtrSet<LiveInterval*, 8>& split);
- unsigned getNumberOfSpills(SmallPtrSet<MachineInstr*, 4>& MIs,
- unsigned Reg, int FrameIndex);
- VNInfo* PerformPHIConstruction(MachineBasicBlock::iterator use,
- MachineBasicBlock* MBB,
- LiveInterval* LI,
+ unsigned getNumberOfNonSpills(SmallPtrSet<MachineInstr*, 4>& MIs,
+ unsigned Reg, int FrameIndex, bool& TwoAddr);
+ VNInfo* PerformPHIConstruction(MachineBasicBlock::iterator Use,
+ MachineBasicBlock* MBB, LiveInterval* LI,
+ SmallPtrSet<MachineInstr*, 4>& Visited,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
+ DenseMap<MachineInstr*, VNInfo*>& NewVNs,
+ DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
+ DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
+ bool IsTopLevel, bool IsIntraBlock);
+ VNInfo* PerformPHIConstructionFallBack(MachineBasicBlock::iterator Use,
+ MachineBasicBlock* MBB, LiveInterval* LI,
SmallPtrSet<MachineInstr*, 4>& Visited,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
DenseMap<MachineInstr*, VNInfo*>& NewVNs,
DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
- bool toplevel, bool intrablock);
+ bool IsTopLevel, bool IsIntraBlock);
};
} // end anonymous namespace
const PassInfo *const llvm::PreAllocSplittingID = &X;
-
-/// findNextEmptySlot - Find a gap after the given machine instruction in the
-/// instruction index map. If there isn't one, return end().
-MachineBasicBlock::iterator
-PreAllocSplitting::findNextEmptySlot(MachineBasicBlock *MBB, MachineInstr *MI,
- unsigned &SpotIndex) {
- MachineBasicBlock::iterator MII = MI;
- if (++MII != MBB->end()) {
- unsigned Index = LIs->findGapBeforeInstr(LIs->getInstructionIndex(MII));
- if (Index) {
- SpotIndex = Index;
- return MII;
- }
- }
- return MBB->end();
-}
-
/// findSpillPoint - Find a gap as far away from the given MI that's suitable
/// for spilling the current live interval. The index must be before any
/// defs and uses of the live interval register in the mbb. Return begin() if
MachineBasicBlock::iterator
PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI,
MachineInstr *DefMI,
- SmallPtrSet<MachineInstr*, 4> &RefsInMBB,
- unsigned &SpillIndex) {
+ SmallPtrSet<MachineInstr*, 4> &RefsInMBB) {
MachineBasicBlock::iterator Pt = MBB->begin();
- // Go top down if RefsInMBB is empty.
- if (RefsInMBB.empty() && !DefMI) {
- MachineBasicBlock::iterator MII = MBB->begin();
- MachineBasicBlock::iterator EndPt = MI;
- do {
- ++MII;
- unsigned Index = LIs->getInstructionIndex(MII);
- unsigned Gap = LIs->findGapBeforeInstr(Index);
- if (Gap) {
- Pt = MII;
- SpillIndex = Gap;
- break;
- }
- } while (MII != EndPt);
- } else {
- MachineBasicBlock::iterator MII = MI;
- MachineBasicBlock::iterator EndPt = DefMI
- ? MachineBasicBlock::iterator(DefMI) : MBB->begin();
- while (MII != EndPt && !RefsInMBB.count(MII)) {
- unsigned Index = LIs->getInstructionIndex(MII);
- if (LIs->hasGapBeforeInstr(Index)) {
- Pt = MII;
- SpillIndex = LIs->findGapBeforeInstr(Index, true);
+ MachineBasicBlock::iterator MII = MI;
+ MachineBasicBlock::iterator EndPt = DefMI
+ ? MachineBasicBlock::iterator(DefMI) : MBB->begin();
+
+ while (MII != EndPt && !RefsInMBB.count(MII) &&
+ MII->getOpcode() != TRI->getCallFrameSetupOpcode())
+ --MII;
+ if (MII == EndPt || RefsInMBB.count(MII)) return Pt;
+
+ while (MII != EndPt && !RefsInMBB.count(MII)) {
+ // We can't insert the spill between the barrier (a call), and its
+ // corresponding call frame setup.
+ if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {
+ while (MII->getOpcode() != TRI->getCallFrameSetupOpcode()) {
+ --MII;
+ if (MII == EndPt) {
+ return Pt;
+ }
}
- --MII;
+ continue;
+ } else {
+ Pt = MII;
}
+
+ if (RefsInMBB.count(MII))
+ return Pt;
+
+
+ --MII;
}
return Pt;
/// found.
MachineBasicBlock::iterator
PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
- unsigned LastIdx,
- SmallPtrSet<MachineInstr*, 4> &RefsInMBB,
- unsigned &RestoreIndex) {
+ SlotIndex LastIdx,
+ SmallPtrSet<MachineInstr*, 4> &RefsInMBB) {
// FIXME: Allow spill to be inserted to the beginning of the mbb. Update mbb
// begin index accordingly.
MachineBasicBlock::iterator Pt = MBB->end();
- unsigned EndIdx = LIs->getMBBEndIdx(MBB);
+ MachineBasicBlock::iterator EndPt = MBB->getFirstTerminator();
- // Go bottom up if RefsInMBB is empty and the end of the mbb isn't beyond
- // the last index in the live range.
- if (RefsInMBB.empty() && LastIdx >= EndIdx) {
- MachineBasicBlock::iterator MII = MBB->getFirstTerminator();
- MachineBasicBlock::iterator EndPt = MI;
- --MII;
- do {
- unsigned Index = LIs->getInstructionIndex(MII);
- unsigned Gap = LIs->findGapBeforeInstr(Index);
- if (Gap) {
- Pt = MII;
- RestoreIndex = Gap;
- break;
- }
- --MII;
- } while (MII != EndPt);
- } else {
- MachineBasicBlock::iterator MII = MI;
- MII = ++MII;
- // FIXME: Limit the number of instructions to examine to reduce
- // compile time?
- while (MII != MBB->end()) {
- unsigned Index = LIs->getInstructionIndex(MII);
- if (Index > LastIdx)
- break;
- unsigned Gap = LIs->findGapBeforeInstr(Index);
- if (Gap) {
- Pt = MII;
- RestoreIndex = Gap;
- }
- if (RefsInMBB.count(MII))
- break;
- ++MII;
+ // We start at the call, so walk forward until we find the call frame teardown
+ // since we can't insert restores before that. Bail if we encounter a use
+ // during this time.
+ MachineBasicBlock::iterator MII = MI;
+ if (MII == EndPt) return Pt;
+
+ while (MII != EndPt && !RefsInMBB.count(MII) &&
+ MII->getOpcode() != TRI->getCallFrameDestroyOpcode())
+ ++MII;
+ if (MII == EndPt || RefsInMBB.count(MII)) return Pt;
+ ++MII;
+
+ // FIXME: Limit the number of instructions to examine to reduce
+ // compile time?
+ while (MII != EndPt) {
+ SlotIndex Index = LIs->getInstructionIndex(MII);
+ if (Index > LastIdx)
+ break;
+
+ // We can't insert a restore between the barrier (a call) and its
+ // corresponding call frame teardown.
+ if (MII->getOpcode() == TRI->getCallFrameSetupOpcode()) {
+ do {
+ if (MII == EndPt || RefsInMBB.count(MII)) return Pt;
+ ++MII;
+ } while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode());
+ } else {
+ Pt = MII;
}
+
+ if (RefsInMBB.count(MII))
+ return Pt;
+
+ ++MII;
}
return Pt;
if (I != IntervalSSMap.end()) {
SS = I->second;
} else {
- SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
+ SS = MFI->CreateSpillStackObject(RC->getSize(), RC->getAlignment());
IntervalSSMap[Reg] = SS;
}
// Create live interval for stack slot.
- CurrSLI = &LSs->getOrCreateInterval(SS);
+ CurrSLI = &LSs->getOrCreateInterval(SS, RC);
if (CurrSLI->hasAtLeastOneValue())
CurrSValNo = CurrSLI->getValNumInfo(0);
else
- CurrSValNo = CurrSLI->getNextValue(~0U, 0, LSs->getVNInfoAllocator());
+ CurrSValNo = CurrSLI->getNextValue(SlotIndex(), 0, false,
+ LSs->getVNInfoAllocator());
return SS;
}
/// slot at the specified index.
bool
PreAllocSplitting::IsAvailableInStack(MachineBasicBlock *DefMBB,
- unsigned Reg, unsigned DefIndex,
- unsigned RestoreIndex, unsigned &SpillIndex,
+ unsigned Reg, SlotIndex DefIndex,
+ SlotIndex RestoreIndex,
+ SlotIndex &SpillIndex,
int& SS) const {
if (!DefMBB)
return false;
- DenseMap<unsigned, int>::iterator I = IntervalSSMap.find(Reg);
+ DenseMap<unsigned, int>::const_iterator I = IntervalSSMap.find(Reg);
if (I == IntervalSSMap.end())
return false;
- DenseMap<unsigned, unsigned>::iterator II = Def2SpillMap.find(DefIndex);
+ DenseMap<SlotIndex, SlotIndex>::const_iterator
+ II = Def2SpillMap.find(DefIndex);
if (II == Def2SpillMap.end())
return false;
/// interval being split, and the spill and restore indicies, update the live
/// interval of the spill stack slot.
void
-PreAllocSplitting::UpdateSpillSlotInterval(VNInfo *ValNo, unsigned SpillIndex,
- unsigned RestoreIndex) {
+PreAllocSplitting::UpdateSpillSlotInterval(VNInfo *ValNo, SlotIndex SpillIndex,
+ SlotIndex RestoreIndex) {
assert(LIs->getMBBFromIndex(RestoreIndex) == BarrierMBB &&
"Expect restore in the barrier mbb");
}
SmallPtrSet<MachineBasicBlock*, 4> Processed;
- unsigned EndIdx = LIs->getMBBEndIdx(MBB);
- LiveRange SLR(SpillIndex, EndIdx+1, CurrSValNo);
+ SlotIndex EndIdx = LIs->getMBBEndIdx(MBB);
+ LiveRange SLR(SpillIndex, EndIdx, CurrSValNo);
CurrSLI->addRange(SLR);
Processed.insert(MBB);
WorkList.pop_back();
if (Processed.count(MBB))
continue;
- unsigned Idx = LIs->getMBBStartIdx(MBB);
+ SlotIndex Idx = LIs->getMBBStartIdx(MBB);
LR = CurrLI->getLiveRangeContaining(Idx);
if (LR && LR->valno == ValNo) {
EndIdx = LIs->getMBBEndIdx(MBB);
CurrSLI->addRange(SLR);
} else if (LR->end > EndIdx) {
// Live range extends beyond end of mbb, process successors.
- LiveRange SLR(Idx, EndIdx+1, CurrSValNo);
+ LiveRange SLR(Idx, EndIdx.getNextIndex(), CurrSValNo);
CurrSLI->addRange(SLR);
for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end(); SI != SE; ++SI)
}
}
-/// UpdateRegisterInterval - Given the specified val# of the current live
-/// interval is being split, and the spill and restore indices, update the live
-/// interval accordingly.
-VNInfo*
-PreAllocSplitting::UpdateRegisterInterval(VNInfo *ValNo, unsigned SpillIndex,
- unsigned RestoreIndex) {
- assert(LIs->getMBBFromIndex(RestoreIndex) == BarrierMBB &&
- "Expect restore in the barrier mbb");
-
- SmallVector<std::pair<unsigned,unsigned>, 4> Before;
- SmallVector<std::pair<unsigned,unsigned>, 4> After;
- SmallVector<unsigned, 4> BeforeKills;
- SmallVector<unsigned, 4> AfterKills;
- SmallPtrSet<const LiveRange*, 4> Processed;
-
- // First, let's figure out which parts of the live interval is now defined
- // by the restore, which are defined by the original definition.
- const LiveRange *LR = CurrLI->getLiveRangeContaining(RestoreIndex);
- After.push_back(std::make_pair(RestoreIndex, LR->end));
- if (CurrLI->isKill(ValNo, LR->end))
- AfterKills.push_back(LR->end);
-
- assert(LR->contains(SpillIndex));
- if (SpillIndex > LR->start) {
- Before.push_back(std::make_pair(LR->start, SpillIndex));
- BeforeKills.push_back(SpillIndex);
- }
- Processed.insert(LR);
-
- // Start from the restore mbb, figure out what part of the live interval
- // are defined by the restore.
- SmallVector<MachineBasicBlock*, 4> WorkList;
- MachineBasicBlock *MBB = BarrierMBB;
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI)
- WorkList.push_back(*SI);
-
- SmallPtrSet<MachineBasicBlock*, 4> ProcessedBlocks;
- ProcessedBlocks.insert(MBB);
-
- while (!WorkList.empty()) {
- MBB = WorkList.back();
- WorkList.pop_back();
- unsigned Idx = LIs->getMBBStartIdx(MBB);
- LR = CurrLI->getLiveRangeContaining(Idx);
- if (LR && LR->valno == ValNo && !Processed.count(LR)) {
- After.push_back(std::make_pair(LR->start, LR->end));
- if (CurrLI->isKill(ValNo, LR->end))
- AfterKills.push_back(LR->end);
- Idx = LIs->getMBBEndIdx(MBB);
- if (LR->end > Idx) {
- // Live range extend beyond at least one mbb. Let's see what other
- // mbbs it reaches.
- LIs->findReachableMBBs(LR->start, LR->end, WorkList);
- }
- Processed.insert(LR);
- }
-
- ProcessedBlocks.insert(MBB);
- if (LR)
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI)
- if (!ProcessedBlocks.count(*SI))
- WorkList.push_back(*SI);
- }
-
- for (LiveInterval::iterator I = CurrLI->begin(), E = CurrLI->end();
- I != E; ++I) {
- LiveRange *LR = I;
- if (LR->valno == ValNo && !Processed.count(LR)) {
- Before.push_back(std::make_pair(LR->start, LR->end));
- if (CurrLI->isKill(ValNo, LR->end))
- BeforeKills.push_back(LR->end);
- }
- }
-
- // Now create new val#s to represent the live ranges defined by the old def
- // those defined by the restore.
- unsigned AfterDef = ValNo->def;
- MachineInstr *AfterCopy = ValNo->copy;
- bool HasPHIKill = ValNo->hasPHIKill;
- CurrLI->removeValNo(ValNo);
- VNInfo *BValNo = (Before.empty())
- ? NULL
- : CurrLI->getNextValue(AfterDef, AfterCopy, LIs->getVNInfoAllocator());
- if (BValNo)
- CurrLI->addKills(BValNo, BeforeKills);
-
- VNInfo *AValNo = (After.empty())
- ? NULL
- : CurrLI->getNextValue(RestoreIndex, 0, LIs->getVNInfoAllocator());
- if (AValNo) {
- AValNo->hasPHIKill = HasPHIKill;
- CurrLI->addKills(AValNo, AfterKills);
- }
-
- for (unsigned i = 0, e = Before.size(); i != e; ++i) {
- unsigned Start = Before[i].first;
- unsigned End = Before[i].second;
- CurrLI->addRange(LiveRange(Start, End, BValNo));
- }
- for (unsigned i = 0, e = After.size(); i != e; ++i) {
- unsigned Start = After[i].first;
- unsigned End = After[i].second;
- CurrLI->addRange(LiveRange(Start, End, AValNo));
- }
-
- return AValNo;
-}
-
-/// ShrinkWrapToLastUse - There are uses of the current live interval in the
-/// given block, shrink wrap the live interval to the last use (i.e. remove
-/// from last use to the end of the mbb). In case mbb is the where the barrier
-/// is, remove from the last use to the barrier.
-bool
-PreAllocSplitting::ShrinkWrapToLastUse(MachineBasicBlock *MBB, VNInfo *ValNo,
- SmallVector<MachineOperand*, 4> &Uses,
- SmallPtrSet<MachineInstr*, 4> &UseMIs) {
- MachineOperand *LastMO = 0;
- MachineInstr *LastMI = 0;
- if (MBB != BarrierMBB && Uses.size() == 1) {
- // Single use, no need to traverse the block. We can't assume this for the
- // barrier bb though since the use is probably below the barrier.
- LastMO = Uses[0];
- LastMI = LastMO->getParent();
- } else {
- MachineBasicBlock::iterator MEE = MBB->begin();
- MachineBasicBlock::iterator MII;
- if (MBB == BarrierMBB)
- MII = Barrier;
- else
- MII = MBB->end();
- while (MII != MEE) {
- --MII;
- MachineInstr *UseMI = &*MII;
- if (!UseMIs.count(UseMI))
- continue;
- for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = UseMI->getOperand(i);
- if (MO.isReg() && MO.getReg() == CurrLI->reg) {
- LastMO = &MO;
- break;
- }
- }
- LastMI = UseMI;
- break;
- }
- }
-
- // Cut off live range from last use (or beginning of the mbb if there
- // are no uses in it) to the end of the mbb.
- unsigned RangeStart, RangeEnd = LIs->getMBBEndIdx(MBB)+1;
- if (LastMI) {
- RangeStart = LIs->getUseIndex(LIs->getInstructionIndex(LastMI))+1;
- assert(!LastMO->isKill() && "Last use already terminates the interval?");
- LastMO->setIsKill();
- } else {
- assert(MBB == BarrierMBB);
- RangeStart = LIs->getMBBStartIdx(MBB);
- }
- if (MBB == BarrierMBB)
- RangeEnd = LIs->getUseIndex(BarrierIdx)+1;
- CurrLI->removeRange(RangeStart, RangeEnd);
- if (LastMI)
- CurrLI->addKill(ValNo, RangeStart);
-
- // Return true if the last use becomes a new kill.
- return LastMI;
-}
-
/// PerformPHIConstruction - From properly set up use and def lists, use a PHI
/// construction algorithm to compute the ranges and valnos for an interval.
-VNInfo* PreAllocSplitting::PerformPHIConstruction(
- MachineBasicBlock::iterator use,
- MachineBasicBlock* MBB,
- LiveInterval* LI,
+VNInfo*
+PreAllocSplitting::PerformPHIConstruction(MachineBasicBlock::iterator UseI,
+ MachineBasicBlock* MBB, LiveInterval* LI,
SmallPtrSet<MachineInstr*, 4>& Visited,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
DenseMap<MachineInstr*, VNInfo*>& NewVNs,
DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
- bool toplevel, bool intrablock) {
+ bool IsTopLevel, bool IsIntraBlock) {
// Return memoized result if it's available.
- if (toplevel && Visited.count(use) && NewVNs.count(use))
- return NewVNs[use];
- else if (!toplevel && intrablock && NewVNs.count(use))
- return NewVNs[use];
- else if (!intrablock && LiveOut.count(MBB))
+ if (IsTopLevel && Visited.count(UseI) && NewVNs.count(UseI))
+ return NewVNs[UseI];
+ else if (!IsTopLevel && IsIntraBlock && NewVNs.count(UseI))
+ return NewVNs[UseI];
+ else if (!IsIntraBlock && LiveOut.count(MBB))
return LiveOut[MBB];
- typedef DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> > RegMap;
-
// Check if our block contains any uses or defs.
bool ContainsDefs = Defs.count(MBB);
bool ContainsUses = Uses.count(MBB);
- VNInfo* ret = 0;
+ VNInfo* RetVNI = 0;
// Enumerate the cases of use/def contaning blocks.
if (!ContainsDefs && !ContainsUses) {
- Fallback:
- // NOTE: Because this is the fallback case from other cases, we do NOT
- // assume that we are not intrablock here.
- if (Phis.count(MBB)) return Phis[MBB];
-
- unsigned StartIndex = LIs->getMBBStartIdx(MBB);
-
- if (MBB->pred_size() == 1) {
- Phis[MBB] = ret = PerformPHIConstruction((*MBB->pred_begin())->end(),
- *(MBB->pred_begin()), LI, Visited,
- Defs, Uses, NewVNs, LiveOut, Phis,
- false, false);
- unsigned EndIndex = 0;
- if (intrablock) {
- EndIndex = LIs->getInstructionIndex(use);
- EndIndex = LiveIntervals::getUseIndex(EndIndex);
- } else
- EndIndex = LIs->getMBBEndIdx(MBB);
-
- LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
- if (intrablock)
- LI->addKill(ret, EndIndex);
- } else {
- Phis[MBB] = ret = LI->getNextValue(~0U, /*FIXME*/ 0,
- LIs->getVNInfoAllocator());
- if (!intrablock) LiveOut[MBB] = ret;
-
- // If there are no uses or defs between our starting point and the
- // beginning of the block, then recursive perform phi construction
- // on our predecessors.
- DenseMap<MachineBasicBlock*, VNInfo*> IncomingVNs;
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- VNInfo* Incoming = PerformPHIConstruction((*PI)->end(), *PI, LI,
- Visited, Defs, Uses, NewVNs,
- LiveOut, Phis, false, false);
- if (Incoming != 0)
- IncomingVNs[*PI] = Incoming;
- }
-
- // Otherwise, merge the incoming VNInfos with a phi join. Create a new
- // VNInfo to represent the joined value.
- for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator I =
- IncomingVNs.begin(), E = IncomingVNs.end(); I != E; ++I) {
- I->second->hasPHIKill = true;
- unsigned KillIndex = LIs->getMBBEndIdx(I->first);
- LI->addKill(I->second, KillIndex);
- }
-
- unsigned EndIndex = 0;
- if (intrablock) {
- EndIndex = LIs->getInstructionIndex(use);
- EndIndex = LiveIntervals::getUseIndex(EndIndex);
- } else
- EndIndex = LIs->getMBBEndIdx(MBB);
- LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
- if (intrablock)
- LI->addKill(ret, EndIndex);
- }
+ return PerformPHIConstructionFallBack(UseI, MBB, LI, Visited, Defs, Uses,
+ NewVNs, LiveOut, Phis,
+ IsTopLevel, IsIntraBlock);
} else if (ContainsDefs && !ContainsUses) {
SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
// instruction we care about, go to the fallback case. Note that that
// should never happen: this cannot be intrablock, so use should
// always be an end() iterator.
- assert(use == MBB->end() && "No use marked in intrablock");
+ assert(UseI == MBB->end() && "No use marked in intrablock");
- MachineBasicBlock::iterator walker = use;
- --walker;
- while (walker != MBB->begin())
- if (BlockDefs.count(walker)) {
+ MachineBasicBlock::iterator Walker = UseI;
+ --Walker;
+ while (Walker != MBB->begin()) {
+ if (BlockDefs.count(Walker))
break;
- } else
- --walker;
+ --Walker;
+ }
// Once we've found it, extend its VNInfo to our instruction.
- unsigned DefIndex = LIs->getInstructionIndex(walker);
- DefIndex = LiveIntervals::getDefIndex(DefIndex);
- unsigned EndIndex = LIs->getMBBEndIdx(MBB);
+ SlotIndex DefIndex = LIs->getInstructionIndex(Walker);
+ DefIndex = DefIndex.getDefIndex();
+ SlotIndex EndIndex = LIs->getMBBEndIdx(MBB);
- ret = NewVNs[walker];
- LI->addRange(LiveRange(DefIndex, EndIndex+1, ret));
+ RetVNI = NewVNs[Walker];
+ LI->addRange(LiveRange(DefIndex, EndIndex, RetVNI));
} else if (!ContainsDefs && ContainsUses) {
SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
// Search for the use in this block that precedes the instruction we care
- // about, going to the fallback case if we don't find it.
-
- if (use == MBB->begin())
- goto Fallback;
-
- MachineBasicBlock::iterator walker = use;
- --walker;
+ // about, going to the fallback case if we don't find it.
+ MachineBasicBlock::iterator Walker = UseI;
bool found = false;
- while (walker != MBB->begin())
- if (BlockUses.count(walker)) {
+ while (Walker != MBB->begin()) {
+ --Walker;
+ if (BlockUses.count(Walker)) {
found = true;
break;
- } else
- --walker;
-
- // Must check begin() too.
- if (!found) {
- if (BlockUses.count(walker))
- found = true;
- else
- goto Fallback;
+ }
}
- unsigned UseIndex = LIs->getInstructionIndex(walker);
- UseIndex = LiveIntervals::getUseIndex(UseIndex);
- unsigned EndIndex = 0;
- if (intrablock) {
- EndIndex = LIs->getInstructionIndex(use);
- EndIndex = LiveIntervals::getUseIndex(EndIndex);
+ if (!found)
+ return PerformPHIConstructionFallBack(UseI, MBB, LI, Visited, Defs,
+ Uses, NewVNs, LiveOut, Phis,
+ IsTopLevel, IsIntraBlock);
+
+ SlotIndex UseIndex = LIs->getInstructionIndex(Walker);
+ UseIndex = UseIndex.getUseIndex();
+ SlotIndex EndIndex;
+ if (IsIntraBlock) {
+ EndIndex = LIs->getInstructionIndex(UseI).getDefIndex();
} else
EndIndex = LIs->getMBBEndIdx(MBB);
// Now, recursively phi construct the VNInfo for the use we found,
// and then extend it to include the instruction we care about
- ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
- NewVNs, LiveOut, Phis, false, true);
+ RetVNI = PerformPHIConstruction(Walker, MBB, LI, Visited, Defs, Uses,
+ NewVNs, LiveOut, Phis, false, true);
- // FIXME: Need to set kills properly for inter-block stuff.
- if (LI->isKill(ret, UseIndex)) LI->removeKill(ret, UseIndex);
- if (intrablock)
- LI->addKill(ret, EndIndex);
+ LI->addRange(LiveRange(UseIndex, EndIndex, RetVNI));
- LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
- } else if (ContainsDefs && ContainsUses){
+ // FIXME: Need to set kills properly for inter-block stuff.
+ if (RetVNI->isKill(UseIndex)) RetVNI->removeKill(UseIndex);
+ if (IsIntraBlock)
+ RetVNI->addKill(EndIndex);
+ } else if (ContainsDefs && ContainsUses) {
SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
// This case is basically a merging of the two preceding case, with the
// special note that checking for defs must take precedence over checking
// for uses, because of two-address instructions.
-
- if (use == MBB->begin())
- goto Fallback;
-
- MachineBasicBlock::iterator walker = use;
- --walker;
+ MachineBasicBlock::iterator Walker = UseI;
bool foundDef = false;
bool foundUse = false;
- while (walker != MBB->begin())
- if (BlockDefs.count(walker)) {
+ while (Walker != MBB->begin()) {
+ --Walker;
+ if (BlockDefs.count(Walker)) {
foundDef = true;
break;
- } else if (BlockUses.count(walker)) {
+ } else if (BlockUses.count(Walker)) {
foundUse = true;
break;
- } else
- --walker;
-
- // Must check begin() too.
- if (!foundDef && !foundUse) {
- if (BlockDefs.count(walker))
- foundDef = true;
- else if (BlockUses.count(walker))
- foundUse = true;
- else
- goto Fallback;
+ }
}
- unsigned StartIndex = LIs->getInstructionIndex(walker);
- StartIndex = foundDef ? LiveIntervals::getDefIndex(StartIndex) :
- LiveIntervals::getUseIndex(StartIndex);
- unsigned EndIndex = 0;
- if (intrablock) {
- EndIndex = LIs->getInstructionIndex(use);
- EndIndex = LiveIntervals::getUseIndex(EndIndex);
+ if (!foundDef && !foundUse)
+ return PerformPHIConstructionFallBack(UseI, MBB, LI, Visited, Defs,
+ Uses, NewVNs, LiveOut, Phis,
+ IsTopLevel, IsIntraBlock);
+
+ SlotIndex StartIndex = LIs->getInstructionIndex(Walker);
+ StartIndex = foundDef ? StartIndex.getDefIndex() : StartIndex.getUseIndex();
+ SlotIndex EndIndex;
+ if (IsIntraBlock) {
+ EndIndex = LIs->getInstructionIndex(UseI).getDefIndex();
} else
EndIndex = LIs->getMBBEndIdx(MBB);
if (foundDef)
- ret = NewVNs[walker];
+ RetVNI = NewVNs[Walker];
else
- ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
- NewVNs, LiveOut, Phis, false, true);
+ RetVNI = PerformPHIConstruction(Walker, MBB, LI, Visited, Defs, Uses,
+ NewVNs, LiveOut, Phis, false, true);
- if (foundUse && LI->isKill(ret, StartIndex))
- LI->removeKill(ret, StartIndex);
- if (intrablock) {
- LI->addKill(ret, EndIndex);
+ LI->addRange(LiveRange(StartIndex, EndIndex, RetVNI));
+
+ if (foundUse && RetVNI->isKill(StartIndex))
+ RetVNI->removeKill(StartIndex);
+ if (IsIntraBlock) {
+ RetVNI->addKill(EndIndex);
}
-
- LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
}
// Memoize results so we don't have to recompute them.
- if (!intrablock) LiveOut[MBB] = ret;
+ if (!IsIntraBlock) LiveOut[MBB] = RetVNI;
+ else {
+ if (!NewVNs.count(UseI))
+ NewVNs[UseI] = RetVNI;
+ Visited.insert(UseI);
+ }
+
+ return RetVNI;
+}
+
+/// PerformPHIConstructionFallBack - PerformPHIConstruction fall back path.
+///
+VNInfo*
+PreAllocSplitting::PerformPHIConstructionFallBack(MachineBasicBlock::iterator UseI,
+ MachineBasicBlock* MBB, LiveInterval* LI,
+ SmallPtrSet<MachineInstr*, 4>& Visited,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
+ DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
+ DenseMap<MachineInstr*, VNInfo*>& NewVNs,
+ DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
+ DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
+ bool IsTopLevel, bool IsIntraBlock) {
+ // NOTE: Because this is the fallback case from other cases, we do NOT
+ // assume that we are not intrablock here.
+ if (Phis.count(MBB)) return Phis[MBB];
+
+ SlotIndex StartIndex = LIs->getMBBStartIdx(MBB);
+ VNInfo *RetVNI = Phis[MBB] =
+ LI->getNextValue(SlotIndex(), /*FIXME*/ 0, false,
+ LIs->getVNInfoAllocator());
+
+ if (!IsIntraBlock) LiveOut[MBB] = RetVNI;
+
+ // If there are no uses or defs between our starting point and the
+ // beginning of the block, then recursive perform phi construction
+ // on our predecessors.
+ DenseMap<MachineBasicBlock*, VNInfo*> IncomingVNs;
+ for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ VNInfo* Incoming = PerformPHIConstruction((*PI)->end(), *PI, LI,
+ Visited, Defs, Uses, NewVNs,
+ LiveOut, Phis, false, false);
+ if (Incoming != 0)
+ IncomingVNs[*PI] = Incoming;
+ }
+
+ if (MBB->pred_size() == 1 && !RetVNI->hasPHIKill()) {
+ VNInfo* OldVN = RetVNI;
+ VNInfo* NewVN = IncomingVNs.begin()->second;
+ VNInfo* MergedVN = LI->MergeValueNumberInto(OldVN, NewVN);
+ if (MergedVN == OldVN) std::swap(OldVN, NewVN);
+
+ for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator LOI = LiveOut.begin(),
+ LOE = LiveOut.end(); LOI != LOE; ++LOI)
+ if (LOI->second == OldVN)
+ LOI->second = MergedVN;
+ for (DenseMap<MachineInstr*, VNInfo*>::iterator NVI = NewVNs.begin(),
+ NVE = NewVNs.end(); NVI != NVE; ++NVI)
+ if (NVI->second == OldVN)
+ NVI->second = MergedVN;
+ for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator PI = Phis.begin(),
+ PE = Phis.end(); PI != PE; ++PI)
+ if (PI->second == OldVN)
+ PI->second = MergedVN;
+ RetVNI = MergedVN;
+ } else {
+ // Otherwise, merge the incoming VNInfos with a phi join. Create a new
+ // VNInfo to represent the joined value.
+ for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator I =
+ IncomingVNs.begin(), E = IncomingVNs.end(); I != E; ++I) {
+ I->second->setHasPHIKill(true);
+ SlotIndex KillIndex(LIs->getMBBEndIdx(I->first), true);
+ if (!I->second->isKill(KillIndex))
+ I->second->addKill(KillIndex);
+ }
+ }
+
+ SlotIndex EndIndex;
+ if (IsIntraBlock) {
+ EndIndex = LIs->getInstructionIndex(UseI).getDefIndex();
+ } else
+ EndIndex = LIs->getMBBEndIdx(MBB);
+ LI->addRange(LiveRange(StartIndex, EndIndex, RetVNI));
+ if (IsIntraBlock)
+ RetVNI->addKill(EndIndex);
+
+ // Memoize results so we don't have to recompute them.
+ if (!IsIntraBlock)
+ LiveOut[MBB] = RetVNI;
else {
- if (!NewVNs.count(use))
- NewVNs[use] = ret;
- Visited.insert(use);
+ if (!NewVNs.count(UseI))
+ NewVNs[UseI] = RetVNI;
+ Visited.insert(UseI);
}
- return ret;
+ return RetVNI;
}
/// ReconstructLiveInterval - Recompute a live interval from scratch.
void PreAllocSplitting::ReconstructLiveInterval(LiveInterval* LI) {
- BumpPtrAllocator& Alloc = LIs->getVNInfoAllocator();
+ VNInfo::Allocator& Alloc = LIs->getVNInfoAllocator();
// Clear the old ranges and valnos;
LI->clear();
DE = MRI->def_end(); DI != DE; ++DI) {
Defs[(*DI).getParent()].insert(&*DI);
- unsigned DefIdx = LIs->getInstructionIndex(&*DI);
- DefIdx = LiveIntervals::getDefIndex(DefIdx);
+ SlotIndex DefIdx = LIs->getInstructionIndex(&*DI);
+ DefIdx = DefIdx.getDefIndex();
- VNInfo* NewVN = LI->getNextValue(DefIdx, 0, Alloc);
+ assert(!DI->isPHI() && "PHI instr in code during pre-alloc splitting.");
+ VNInfo* NewVN = LI->getNextValue(DefIdx, 0, true, Alloc);
// If the def is a move, set the copy field.
unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
if (TII->isMoveInstr(*DI, SrcReg, DstReg, SrcSubIdx, DstSubIdx))
if (DstReg == LI->reg)
- NewVN->copy = &*DI;
+ NewVN->setCopy(&*DI);
NewVNs[&*DI] = NewVN;
}
// Add ranges for dead defs
for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(LI->reg),
DE = MRI->def_end(); DI != DE; ++DI) {
- unsigned DefIdx = LIs->getInstructionIndex(&*DI);
- DefIdx = LiveIntervals::getDefIndex(DefIdx);
+ SlotIndex DefIdx = LIs->getInstructionIndex(&*DI);
+ DefIdx = DefIdx.getDefIndex();
if (LI->liveAt(DefIdx)) continue;
VNInfo* DeadVN = NewVNs[&*DI];
- LI->addRange(LiveRange(DefIdx, DefIdx+1, DeadVN));
- LI->addKill(DeadVN, DefIdx);
+ LI->addRange(LiveRange(DefIdx, DefIdx.getNextSlot(), DeadVN));
+ DeadVN->addKill(DefIdx);
}
-}
-
-/// ShrinkWrapLiveInterval - Recursively traverse the predecessor
-/// chain to find the new 'kills' and shrink wrap the live interval to the
-/// new kill indices.
-void
-PreAllocSplitting::ShrinkWrapLiveInterval(VNInfo *ValNo, MachineBasicBlock *MBB,
- MachineBasicBlock *SuccMBB, MachineBasicBlock *DefMBB,
- SmallPtrSet<MachineBasicBlock*, 8> &Visited,
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > &Uses,
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > &UseMIs,
- SmallVector<MachineBasicBlock*, 4> &UseMBBs) {
- if (Visited.count(MBB))
- return;
- // If live interval is live in another successor path, then we can't process
- // this block. But we may able to do so after all the successors have been
- // processed.
- if (MBB != BarrierMBB) {
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock *SMBB = *SI;
- if (SMBB == SuccMBB)
+ // Update kill markers.
+ for (LiveInterval::vni_iterator VI = LI->vni_begin(), VE = LI->vni_end();
+ VI != VE; ++VI) {
+ VNInfo* VNI = *VI;
+ for (unsigned i = 0, e = VNI->kills.size(); i != e; ++i) {
+ SlotIndex KillIdx = VNI->kills[i];
+ if (KillIdx.isPHI())
continue;
- if (CurrLI->liveAt(LIs->getMBBStartIdx(SMBB)))
- return;
- }
- }
-
- Visited.insert(MBB);
-
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
- UMII = Uses.find(MBB);
- if (UMII != Uses.end()) {
- // At least one use in this mbb, lets look for the kill.
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
- UMII2 = UseMIs.find(MBB);
- if (ShrinkWrapToLastUse(MBB, ValNo, UMII->second, UMII2->second))
- // Found a kill, shrink wrapping of this path ends here.
- return;
- } else if (MBB == DefMBB) {
- // There are no uses after the def.
- MachineInstr *DefMI = LIs->getInstructionFromIndex(ValNo->def);
- if (UseMBBs.empty()) {
- // The only use must be below barrier in the barrier block. It's safe to
- // remove the def.
- LIs->RemoveMachineInstrFromMaps(DefMI);
- DefMI->eraseFromParent();
- CurrLI->removeRange(ValNo->def, LIs->getMBBEndIdx(MBB)+1);
- }
- } else if (MBB == BarrierMBB) {
- // Remove entire live range from start of mbb to barrier.
- CurrLI->removeRange(LIs->getMBBStartIdx(MBB),
- LIs->getUseIndex(BarrierIdx)+1);
- } else {
- // Remove entire live range of the mbb out of the live interval.
- CurrLI->removeRange(LIs->getMBBStartIdx(MBB), LIs->getMBBEndIdx(MBB)+1);
- }
-
- if (MBB == DefMBB)
- // Reached the def mbb, stop traversing this path further.
- return;
-
- // Traverse the pathes up the predecessor chains further.
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- MachineBasicBlock *Pred = *PI;
- if (Pred == MBB)
- continue;
- if (Pred == DefMBB && ValNo->hasPHIKill)
- // Pred is the def bb and the def reaches other val#s, we must
- // allow the value to be live out of the bb.
- continue;
- if (!CurrLI->liveAt(LIs->getMBBEndIdx(Pred)-1))
- return;
- ShrinkWrapLiveInterval(ValNo, Pred, MBB, DefMBB, Visited,
- Uses, UseMIs, UseMBBs);
- }
-
- return;
-}
-
-
-void PreAllocSplitting::RepairLiveInterval(LiveInterval* CurrLI,
- VNInfo* ValNo,
- MachineInstr* DefMI,
- unsigned RestoreIdx) {
- // Shrink wrap the live interval by walking up the CFG and find the
- // new kills.
- // Now let's find all the uses of the val#.
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > Uses;
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > UseMIs;
- SmallPtrSet<MachineBasicBlock*, 4> Seen;
- SmallVector<MachineBasicBlock*, 4> UseMBBs;
- for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(CurrLI->reg),
- UE = MRI->use_end(); UI != UE; ++UI) {
- MachineOperand &UseMO = UI.getOperand();
- MachineInstr *UseMI = UseMO.getParent();
- unsigned UseIdx = LIs->getInstructionIndex(UseMI);
- LiveInterval::iterator ULR = CurrLI->FindLiveRangeContaining(UseIdx);
- if (ULR->valno != ValNo)
- continue;
- MachineBasicBlock *UseMBB = UseMI->getParent();
- // Remember which other mbb's use this val#.
- if (Seen.insert(UseMBB) && UseMBB != BarrierMBB)
- UseMBBs.push_back(UseMBB);
- DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
- UMII = Uses.find(UseMBB);
- if (UMII != Uses.end()) {
- DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
- UMII2 = UseMIs.find(UseMBB);
- UMII->second.push_back(&UseMO);
- UMII2->second.insert(UseMI);
- } else {
- SmallVector<MachineOperand*, 4> Ops;
- Ops.push_back(&UseMO);
- Uses.insert(std::make_pair(UseMBB, Ops));
- SmallPtrSet<MachineInstr*, 4> MIs;
- MIs.insert(UseMI);
- UseMIs.insert(std::make_pair(UseMBB, MIs));
+ MachineInstr *KillMI = LIs->getInstructionFromIndex(KillIdx);
+ if (KillMI) {
+ MachineOperand *KillMO = KillMI->findRegisterUseOperand(CurrLI->reg);
+ if (KillMO)
+ // It could be a dead def.
+ KillMO->setIsKill();
+ }
}
}
-
- // Walk up the predecessor chains.
- SmallPtrSet<MachineBasicBlock*, 8> Visited;
- ShrinkWrapLiveInterval(ValNo, BarrierMBB, NULL, DefMI->getParent(), Visited,
- Uses, UseMIs, UseMBBs);
-
- // Remove live range from barrier to the restore. FIXME: Find a better
- // point to re-start the live interval.
- VNInfo* AfterValNo = UpdateRegisterInterval(ValNo,
- LIs->getUseIndex(BarrierIdx)+1,
- LIs->getDefIndex(RestoreIdx));
-
- // Attempt to renumber the new valno into a new vreg.
- RenumberValno(AfterValNo);
}
/// RenumberValno - Split the given valno out into a new vreg, allowing it to
// Bail out if we ever encounter a valno that has a PHI kill. We can't
// renumber these.
- if (OldVN->hasPHIKill) return;
+ if (OldVN->hasPHIKill()) return;
VNsToCopy.push_back(OldVN);
// Locate two-address redefinitions
- for (SmallVector<unsigned, 4>::iterator KI = OldVN->kills.begin(),
+ for (VNInfo::KillSet::iterator KI = OldVN->kills.begin(),
KE = OldVN->kills.end(); KI != KE; ++KI) {
+ assert(!KI->isPHI() &&
+ "VN previously reported having no PHI kills.");
MachineInstr* MI = LIs->getInstructionFromIndex(*KI);
- //if (!MI) continue;
unsigned DefIdx = MI->findRegisterDefOperandIdx(CurrLI->reg);
if (DefIdx == ~0U) continue;
- if (MI->isRegReDefinedByTwoAddr(DefIdx)) {
+ if (MI->isRegTiedToUseOperand(DefIdx)) {
VNInfo* NextVN =
- CurrLI->findDefinedVNInfo(LiveIntervals::getDefIndex(*KI));
+ CurrLI->findDefinedVNInfoForRegInt(KI->getDefIndex());
+ if (NextVN == OldVN) continue;
Stack.push_back(NextVN);
}
}
VNInfo* OldVN = *OI;
// Copy the valno over
- VNInfo* NewVN = NewLI.getNextValue(OldVN->def, OldVN->copy,
- LIs->getVNInfoAllocator());
- NewLI.copyValNumInfo(NewVN, OldVN);
+ VNInfo* NewVN = NewLI.createValueCopy(OldVN, LIs->getVNInfoAllocator());
NewLI.MergeValueInAsValue(*CurrLI, OldVN, NewVN);
// Remove the valno from the old interval
for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(CurrLI->reg),
E = MRI->reg_end(); I != E; ++I) {
MachineOperand& MO = I.getOperand();
- unsigned InstrIdx = LIs->getInstructionIndex(&*I);
+ SlotIndex InstrIdx = LIs->getInstructionIndex(&*I);
- if ((MO.isUse() && NewLI.liveAt(LiveIntervals::getUseIndex(InstrIdx))) ||
- (MO.isDef() && NewLI.liveAt(LiveIntervals::getDefIndex(InstrIdx))))
+ if ((MO.isUse() && NewLI.liveAt(InstrIdx.getUseIndex())) ||
+ (MO.isDef() && NewLI.liveAt(InstrIdx.getDefIndex())))
OpsToChange.push_back(std::make_pair(&*I, I.getOperandNo()));
}
MO.setReg(NewVReg);
}
+ // Grow the VirtRegMap, since we've created a new vreg.
+ VRM->grow();
+
+ // The renumbered vreg shares a stack slot with the old register.
+ if (IntervalSSMap.count(CurrLI->reg))
+ IntervalSSMap[NewVReg] = IntervalSSMap[CurrLI->reg];
+
NumRenumbers++;
}
-bool PreAllocSplitting::Rematerialize(unsigned vreg, VNInfo* ValNo,
+bool PreAllocSplitting::Rematerialize(unsigned VReg, VNInfo* ValNo,
MachineInstr* DefMI,
MachineBasicBlock::iterator RestorePt,
- unsigned RestoreIdx,
SmallPtrSet<MachineInstr*, 4>& RefsInMBB) {
MachineBasicBlock& MBB = *RestorePt->getParent();
MachineBasicBlock::iterator KillPt = BarrierMBB->end();
- unsigned KillIdx = 0;
- if (ValNo->def == ~0U || DefMI->getParent() == BarrierMBB)
- KillPt = findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB, KillIdx);
+ if (!ValNo->isDefAccurate() || DefMI->getParent() == BarrierMBB)
+ KillPt = findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB);
else
- KillPt = findNextEmptySlot(DefMI->getParent(), DefMI, KillIdx);
+ KillPt = llvm::next(MachineBasicBlock::iterator(DefMI));
if (KillPt == DefMI->getParent()->end())
return false;
- TII->reMaterialize(MBB, RestorePt, vreg, DefMI);
- LIs->InsertMachineInstrInMaps(prior(RestorePt), RestoreIdx);
+ TII->reMaterialize(MBB, RestorePt, VReg, 0, DefMI, TRI);
+ SlotIndex RematIdx = LIs->InsertMachineInstrInMaps(prior(RestorePt));
- if (KillPt->getParent() == BarrierMBB) {
- VNInfo* After = UpdateRegisterInterval(ValNo, LIs->getUseIndex(KillIdx)+1,
- LIs->getDefIndex(RestoreIdx));
-
- RenumberValno(After);
-
- ++NumSplits;
- ++NumRemats;
- return true;
- }
-
- RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIdx);
+ ReconstructLiveInterval(CurrLI);
+ RematIdx = RematIdx.getDefIndex();
+ RenumberValno(CurrLI->findDefinedVNInfoForRegInt(RematIdx));
++NumSplits;
++NumRemats;
MachineBasicBlock* MBB,
int& SS,
SmallPtrSet<MachineInstr*, 4>& RefsInMBB) {
- MachineBasicBlock::iterator Pt = MBB->begin();
-
// Go top down if RefsInMBB is empty.
if (RefsInMBB.empty())
return 0;
if (I != IntervalSSMap.end()) {
SS = I->second;
} else {
- SS = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
-
+ SS = MFI->CreateSpillStackObject(RC->getSize(), RC->getAlignment());
}
MachineInstr* FMI = TII->foldMemoryOperand(*MBB->getParent(),
++NumFolds;
IntervalSSMap[vreg] = SS;
- CurrSLI = &LSs->getOrCreateInterval(SS);
+ CurrSLI = &LSs->getOrCreateInterval(SS, RC);
if (CurrSLI->hasAtLeastOneValue())
CurrSValNo = CurrSLI->getValNumInfo(0);
else
- CurrSValNo = CurrSLI->getNextValue(~0U, 0, LSs->getVNInfoAllocator());
+ CurrSValNo = CurrSLI->getNextValue(SlotIndex(), 0, false,
+ LSs->getVNInfoAllocator());
+ }
+
+ return FMI;
+}
+
+MachineInstr* PreAllocSplitting::FoldRestore(unsigned vreg,
+ const TargetRegisterClass* RC,
+ MachineInstr* Barrier,
+ MachineBasicBlock* MBB,
+ int SS,
+ SmallPtrSet<MachineInstr*, 4>& RefsInMBB) {
+ if ((int)RestoreFoldLimit != -1 && RestoreFoldLimit == (int)NumRestoreFolds)
+ return 0;
+
+ // Go top down if RefsInMBB is empty.
+ if (RefsInMBB.empty())
+ return 0;
+
+ // Can't fold a restore between a call stack setup and teardown.
+ MachineBasicBlock::iterator FoldPt = Barrier;
+
+ // Advance from barrier to call frame teardown.
+ while (FoldPt != MBB->getFirstTerminator() &&
+ FoldPt->getOpcode() != TRI->getCallFrameDestroyOpcode()) {
+ if (RefsInMBB.count(FoldPt))
+ return 0;
+
+ ++FoldPt;
+ }
+
+ if (FoldPt == MBB->getFirstTerminator())
+ return 0;
+ else
+ ++FoldPt;
+
+ // Now find the restore point.
+ while (FoldPt != MBB->getFirstTerminator() && !RefsInMBB.count(FoldPt)) {
+ if (FoldPt->getOpcode() == TRI->getCallFrameSetupOpcode()) {
+ while (FoldPt != MBB->getFirstTerminator() &&
+ FoldPt->getOpcode() != TRI->getCallFrameDestroyOpcode()) {
+ if (RefsInMBB.count(FoldPt))
+ return 0;
+
+ ++FoldPt;
+ }
+
+ if (FoldPt == MBB->getFirstTerminator())
+ return 0;
+ }
+
+ ++FoldPt;
+ }
+
+ if (FoldPt == MBB->getFirstTerminator())
+ return 0;
+
+ int OpIdx = FoldPt->findRegisterUseOperandIdx(vreg, true);
+ if (OpIdx == -1)
+ return 0;
+
+ SmallVector<unsigned, 1> Ops;
+ Ops.push_back(OpIdx);
+
+ if (!TII->canFoldMemoryOperand(FoldPt, Ops))
+ return 0;
+
+ MachineInstr* FMI = TII->foldMemoryOperand(*MBB->getParent(),
+ FoldPt, Ops, SS);
+
+ if (FMI) {
+ LIs->ReplaceMachineInstrInMaps(FoldPt, FMI);
+ FMI = MBB->insert(MBB->erase(FoldPt), FMI);
+ ++NumRestoreFolds;
}
return FMI;
/// so it would not cross the barrier that's being processed. Shrink wrap
/// (minimize) the live interval to the last uses.
bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) {
+ DEBUG(dbgs() << "Pre-alloc splitting " << LI->reg << " for " << *Barrier
+ << " result: ");
+
CurrLI = LI;
// Find live range where current interval cross the barrier.
LiveInterval::iterator LR =
- CurrLI->FindLiveRangeContaining(LIs->getUseIndex(BarrierIdx));
+ CurrLI->FindLiveRangeContaining(BarrierIdx.getUseIndex());
VNInfo *ValNo = LR->valno;
- if (ValNo->def == ~1U) {
- // Defined by a dead def? How can this be?
- assert(0 && "Val# is defined by a dead def?");
- abort();
- }
+ assert(!ValNo->isUnused() && "Val# is defined by a dead def?");
- MachineInstr *DefMI = (ValNo->def != ~0U)
+ MachineInstr *DefMI = ValNo->isDefAccurate()
? LIs->getInstructionFromIndex(ValNo->def) : NULL;
// If this would create a new join point, do not split.
- if (DefMI && createsNewJoin(LR, DefMI->getParent(), Barrier->getParent()))
+ if (DefMI && createsNewJoin(LR, DefMI->getParent(), Barrier->getParent())) {
+ DEBUG(dbgs() << "FAILED (would create a new join point).\n");
return false;
+ }
// Find all references in the barrier mbb.
SmallPtrSet<MachineInstr*, 4> RefsInMBB;
}
// Find a point to restore the value after the barrier.
- unsigned RestoreIndex;
MachineBasicBlock::iterator RestorePt =
- findRestorePoint(BarrierMBB, Barrier, LR->end, RefsInMBB, RestoreIndex);
- if (RestorePt == BarrierMBB->end())
+ findRestorePoint(BarrierMBB, Barrier, LR->end, RefsInMBB);
+ if (RestorePt == BarrierMBB->end()) {
+ DEBUG(dbgs() << "FAILED (could not find a suitable restore point).\n");
return false;
+ }
if (DefMI && LIs->isReMaterializable(*LI, ValNo, DefMI))
- if (Rematerialize(LI->reg, ValNo, DefMI, RestorePt,
- RestoreIndex, RefsInMBB))
- return true;
+ if (Rematerialize(LI->reg, ValNo, DefMI, RestorePt, RefsInMBB)) {
+ DEBUG(dbgs() << "success (remat).\n");
+ return true;
+ }
// Add a spill either before the barrier or after the definition.
MachineBasicBlock *DefMBB = DefMI ? DefMI->getParent() : NULL;
const TargetRegisterClass *RC = MRI->getRegClass(CurrLI->reg);
- unsigned SpillIndex = 0;
+ SlotIndex SpillIndex;
MachineInstr *SpillMI = NULL;
int SS = -1;
- if (ValNo->def == ~0U) {
- // If it's defined by a phi, we must split just before the barrier.
+ if (!ValNo->isDefAccurate()) {
+ // If we don't know where the def is we must split just before the barrier.
if ((SpillMI = FoldSpill(LI->reg, RC, 0, Barrier,
BarrierMBB, SS, RefsInMBB))) {
SpillIndex = LIs->getInstructionIndex(SpillMI);
} else {
MachineBasicBlock::iterator SpillPt =
- findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB, SpillIndex);
- if (SpillPt == BarrierMBB->begin())
+ findSpillPoint(BarrierMBB, Barrier, NULL, RefsInMBB);
+ if (SpillPt == BarrierMBB->begin()) {
+ DEBUG(dbgs() << "FAILED (could not find a suitable spill point).\n");
return false; // No gap to insert spill.
+ }
// Add spill.
SS = CreateSpillStackSlot(CurrLI->reg, RC);
TII->storeRegToStackSlot(*BarrierMBB, SpillPt, CurrLI->reg, true, SS, RC);
SpillMI = prior(SpillPt);
- LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
+ SpillIndex = LIs->InsertMachineInstrInMaps(SpillMI);
}
} else if (!IsAvailableInStack(DefMBB, CurrLI->reg, ValNo->def,
- RestoreIndex, SpillIndex, SS)) {
+ LIs->getZeroIndex(), SpillIndex, SS)) {
// If it's already split, just restore the value. There is no need to spill
// the def again.
- if (!DefMI)
+ if (!DefMI) {
+ DEBUG(dbgs() << "FAILED (def is dead).\n");
return false; // Def is dead. Do nothing.
+ }
if ((SpillMI = FoldSpill(LI->reg, RC, DefMI, Barrier,
- BarrierMBB, SS, RefsInMBB))) {
+ BarrierMBB, SS, RefsInMBB))) {
SpillIndex = LIs->getInstructionIndex(SpillMI);
} else {
// Check if it's possible to insert a spill after the def MI.
if (DefMBB == BarrierMBB) {
// Add spill after the def and the last use before the barrier.
SpillPt = findSpillPoint(BarrierMBB, Barrier, DefMI,
- RefsInMBB, SpillIndex);
- if (SpillPt == DefMBB->begin())
+ RefsInMBB);
+ if (SpillPt == DefMBB->begin()) {
+ DEBUG(dbgs() << "FAILED (could not find a suitable spill point).\n");
return false; // No gap to insert spill.
+ }
} else {
- SpillPt = findNextEmptySlot(DefMBB, DefMI, SpillIndex);
- if (SpillPt == DefMBB->end())
+ SpillPt = llvm::next(MachineBasicBlock::iterator(DefMI));
+ if (SpillPt == DefMBB->end()) {
+ DEBUG(dbgs() << "FAILED (could not find a suitable spill point).\n");
return false; // No gap to insert spill.
+ }
}
- // Add spill. The store instruction kills the register if def is before
- // the barrier in the barrier block.
+ // Add spill.
SS = CreateSpillStackSlot(CurrLI->reg, RC);
- TII->storeRegToStackSlot(*DefMBB, SpillPt, CurrLI->reg,
- DefMBB == BarrierMBB, SS, RC);
+ TII->storeRegToStackSlot(*DefMBB, SpillPt, CurrLI->reg, false, SS, RC);
SpillMI = prior(SpillPt);
- LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex);
+ SpillIndex = LIs->InsertMachineInstrInMaps(SpillMI);
}
}
Def2SpillMap[ValNo->def] = SpillIndex;
// Add restore.
- TII->loadRegFromStackSlot(*BarrierMBB, RestorePt, CurrLI->reg, SS, RC);
- MachineInstr *LoadMI = prior(RestorePt);
- LIs->InsertMachineInstrInMaps(LoadMI, RestoreIndex);
-
- // If live interval is spilled in the same block as the barrier, just
- // create a hole in the interval.
- if (!DefMBB ||
- (SpillMI && SpillMI->getParent() == BarrierMBB)) {
- // Update spill stack slot live interval.
- UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
- LIs->getDefIndex(RestoreIndex));
-
- VNInfo* After = UpdateRegisterInterval(ValNo,
- LIs->getUseIndex(SpillIndex)+1,
- LIs->getDefIndex(RestoreIndex));
- RenumberValno(After);
-
- ++NumSplits;
- return true;
+ bool FoldedRestore = false;
+ SlotIndex RestoreIndex;
+ if (MachineInstr* LMI = FoldRestore(CurrLI->reg, RC, Barrier,
+ BarrierMBB, SS, RefsInMBB)) {
+ RestorePt = LMI;
+ RestoreIndex = LIs->getInstructionIndex(RestorePt);
+ FoldedRestore = true;
+ } else {
+ TII->loadRegFromStackSlot(*BarrierMBB, RestorePt, CurrLI->reg, SS, RC);
+ MachineInstr *LoadMI = prior(RestorePt);
+ RestoreIndex = LIs->InsertMachineInstrInMaps(LoadMI);
}
// Update spill stack slot live interval.
- UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
- LIs->getDefIndex(RestoreIndex));
+ UpdateSpillSlotInterval(ValNo, SpillIndex.getUseIndex().getNextSlot(),
+ RestoreIndex.getDefIndex());
- RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIndex);
+ ReconstructLiveInterval(CurrLI);
+
+ if (!FoldedRestore) {
+ SlotIndex RestoreIdx = LIs->getInstructionIndex(prior(RestorePt));
+ RestoreIdx = RestoreIdx.getDefIndex();
+ RenumberValno(CurrLI->findDefinedVNInfoForRegInt(RestoreIdx));
+ }
++NumSplits;
+ DEBUG(dbgs() << "success.\n");
return true;
}
// by the current barrier.
SmallVector<LiveInterval*, 8> Intervals;
for (const TargetRegisterClass **RC = RCs; *RC; ++RC) {
- if (TII->IgnoreRegisterClassBarriers(*RC))
+ // FIXME: If it's not safe to move any instruction that defines the barrier
+ // register class, then it means there are some special dependencies which
+ // codegen is not modelling. Ignore these barriers for now.
+ if (!TII->isSafeToMoveRegClassDefs(*RC))
continue;
std::vector<unsigned> &VRs = MRI->getRegClassVirtRegs(*RC);
for (unsigned i = 0, e = VRs.size(); i != e; ++i) {
while (!Intervals.empty()) {
if (PreSplitLimit != -1 && (int)NumSplits == PreSplitLimit)
break;
- else if (NumSplits == 4)
- Change |= Change;
LiveInterval *LI = Intervals.back();
Intervals.pop_back();
bool result = SplitRegLiveInterval(LI);
return Change;
}
-unsigned PreAllocSplitting::getNumberOfSpills(
+unsigned PreAllocSplitting::getNumberOfNonSpills(
SmallPtrSet<MachineInstr*, 4>& MIs,
- unsigned Reg, int FrameIndex) {
- unsigned Spills = 0;
+ unsigned Reg, int FrameIndex,
+ bool& FeedsTwoAddr) {
+ unsigned NonSpills = 0;
for (SmallPtrSet<MachineInstr*, 4>::iterator UI = MIs.begin(), UE = MIs.end();
- UI != UI; ++UI) {
+ UI != UE; ++UI) {
int StoreFrameIndex;
unsigned StoreVReg = TII->isStoreToStackSlot(*UI, StoreFrameIndex);
- if (StoreVReg == Reg && StoreFrameIndex == FrameIndex)
- Spills++;
+ if (StoreVReg != Reg || StoreFrameIndex != FrameIndex)
+ NonSpills++;
+
+ int DefIdx = (*UI)->findRegisterDefOperandIdx(Reg);
+ if (DefIdx != -1 && (*UI)->isRegTiedToUseOperand(DefIdx))
+ FeedsTwoAddr = true;
}
- return Spills;
+ return NonSpills;
}
/// removeDeadSpills - After doing splitting, filter through all intervals we've
bool PreAllocSplitting::removeDeadSpills(SmallPtrSet<LiveInterval*, 8>& split) {
bool changed = false;
+ // Walk over all of the live intervals that were touched by the splitter,
+ // and see if we can do any DCE and/or folding.
for (SmallPtrSet<LiveInterval*, 8>::iterator LI = split.begin(),
LE = split.end(); LI != LE; ++LI) {
DenseMap<VNInfo*, SmallPtrSet<MachineInstr*, 4> > VNUseCount;
+ // First, collect all the uses of the vreg, and sort them by their
+ // reaching definition (VNInfo).
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin((*LI)->reg),
UE = MRI->use_end(); UI != UE; ++UI) {
- unsigned index = LIs->getInstructionIndex(&*UI);
- index = LiveIntervals::getUseIndex(index);
+ SlotIndex index = LIs->getInstructionIndex(&*UI);
+ index = index.getUseIndex();
const LiveRange* LR = (*LI)->getLiveRangeContaining(index);
VNUseCount[LR->valno].insert(&*UI);
}
+ // Now, take the definitions (VNInfo's) one at a time and try to DCE
+ // and/or fold them away.
for (LiveInterval::vni_iterator VI = (*LI)->vni_begin(),
VE = (*LI)->vni_end(); VI != VE; ++VI) {
+
+ if (DeadSplitLimit != -1 && (int)NumDeadSpills == DeadSplitLimit)
+ return changed;
+
VNInfo* CurrVN = *VI;
- if (CurrVN->hasPHIKill) continue;
- unsigned DefIdx = CurrVN->def;
- if (DefIdx == ~0U || DefIdx == ~1U) continue;
+ // We don't currently try to handle definitions with PHI kills, because
+ // it would involve processing more than one VNInfo at once.
+ if (CurrVN->hasPHIKill()) continue;
+
+ // We also don't try to handle the results of PHI joins, since there's
+ // no defining instruction to analyze.
+ if (!CurrVN->isDefAccurate() || CurrVN->isUnused()) continue;
- MachineInstr* DefMI = LIs->getInstructionFromIndex(DefIdx);
+ // We're only interested in eliminating cruft introduced by the splitter,
+ // is of the form load-use or load-use-store. First, check that the
+ // definition is a load, and remember what stack slot we loaded it from.
+ MachineInstr* DefMI = LIs->getInstructionFromIndex(CurrVN->def);
int FrameIndex;
if (!TII->isLoadFromStackSlot(DefMI, FrameIndex)) continue;
+ // If the definition has no uses at all, just DCE it.
if (VNUseCount[CurrVN].size() == 0) {
LIs->RemoveMachineInstrFromMaps(DefMI);
(*LI)->removeValNo(CurrVN);
DefMI->eraseFromParent();
+ VNUseCount.erase(CurrVN);
NumDeadSpills++;
changed = true;
continue;
}
- unsigned SpillCount = getNumberOfSpills(VNUseCount[CurrVN],
- (*LI)->reg, FrameIndex);
- if (SpillCount != VNUseCount[CurrVN].size()) continue;
+ // Second, get the number of non-store uses of the definition, as well as
+ // a flag indicating whether it feeds into a later two-address definition.
+ bool FeedsTwoAddr = false;
+ unsigned NonSpillCount = getNumberOfNonSpills(VNUseCount[CurrVN],
+ (*LI)->reg, FrameIndex,
+ FeedsTwoAddr);
+
+ // If there's one non-store use and it doesn't feed a two-addr, then
+ // this is a load-use-store case that we can try to fold.
+ if (NonSpillCount == 1 && !FeedsTwoAddr) {
+ // Start by finding the non-store use MachineInstr.
+ SmallPtrSet<MachineInstr*, 4>::iterator UI = VNUseCount[CurrVN].begin();
+ int StoreFrameIndex;
+ unsigned StoreVReg = TII->isStoreToStackSlot(*UI, StoreFrameIndex);
+ while (UI != VNUseCount[CurrVN].end() &&
+ (StoreVReg == (*LI)->reg && StoreFrameIndex == FrameIndex)) {
+ ++UI;
+ if (UI != VNUseCount[CurrVN].end())
+ StoreVReg = TII->isStoreToStackSlot(*UI, StoreFrameIndex);
+ }
+ if (UI == VNUseCount[CurrVN].end()) continue;
+
+ MachineInstr* use = *UI;
+ // Attempt to fold it away!
+ int OpIdx = use->findRegisterUseOperandIdx((*LI)->reg, false);
+ if (OpIdx == -1) continue;
+ SmallVector<unsigned, 1> Ops;
+ Ops.push_back(OpIdx);
+ if (!TII->canFoldMemoryOperand(use, Ops)) continue;
+
+ MachineInstr* NewMI =
+ TII->foldMemoryOperand(*use->getParent()->getParent(),
+ use, Ops, FrameIndex);
+
+ if (!NewMI) continue;
+
+ // Update relevant analyses.
+ LIs->RemoveMachineInstrFromMaps(DefMI);
+ LIs->ReplaceMachineInstrInMaps(use, NewMI);
+ (*LI)->removeValNo(CurrVN);
+
+ DefMI->eraseFromParent();
+ MachineBasicBlock* MBB = use->getParent();
+ NewMI = MBB->insert(MBB->erase(use), NewMI);
+ VNUseCount[CurrVN].erase(use);
+
+ // Remove deleted instructions. Note that we need to remove them from
+ // the VNInfo->use map as well, just to be safe.
+ for (SmallPtrSet<MachineInstr*, 4>::iterator II =
+ VNUseCount[CurrVN].begin(), IE = VNUseCount[CurrVN].end();
+ II != IE; ++II) {
+ for (DenseMap<VNInfo*, SmallPtrSet<MachineInstr*, 4> >::iterator
+ VNI = VNUseCount.begin(), VNE = VNUseCount.end(); VNI != VNE;
+ ++VNI)
+ if (VNI->first != CurrVN)
+ VNI->second.erase(*II);
+ LIs->RemoveMachineInstrFromMaps(*II);
+ (*II)->eraseFromParent();
+ }
+
+ VNUseCount.erase(CurrVN);
+
+ for (DenseMap<VNInfo*, SmallPtrSet<MachineInstr*, 4> >::iterator
+ VI = VNUseCount.begin(), VE = VNUseCount.end(); VI != VE; ++VI)
+ if (VI->second.erase(use))
+ VI->second.insert(NewMI);
+
+ NumDeadSpills++;
+ changed = true;
+ continue;
+ }
+
+ // If there's more than one non-store instruction, we can't profitably
+ // fold it, so bail.
+ if (NonSpillCount) continue;
+
+ // Otherwise, this is a load-store case, so DCE them.
for (SmallPtrSet<MachineInstr*, 4>::iterator UI =
VNUseCount[CurrVN].begin(), UE = VNUseCount[CurrVN].end();
- UI != UI; ++UI) {
+ UI != UE; ++UI) {
LIs->RemoveMachineInstrFromMaps(*UI);
(*UI)->eraseFromParent();
}
+ VNUseCount.erase(CurrVN);
+
LIs->RemoveMachineInstrFromMaps(DefMI);
(*LI)->removeValNo(CurrVN);
DefMI->eraseFromParent();
if (DefMBB == BarrierMBB)
return false;
- if (LR->valno->hasPHIKill)
+ if (LR->valno->hasPHIKill())
return false;
- unsigned MBBEnd = LIs->getMBBEndIdx(BarrierMBB);
+ SlotIndex MBBEnd = LIs->getMBBEndIdx(BarrierMBB);
if (LR->end < MBBEnd)
return false;
bool PreAllocSplitting::runOnMachineFunction(MachineFunction &MF) {
CurrMF = &MF;
TM = &MF.getTarget();
+ TRI = TM->getRegisterInfo();
TII = TM->getInstrInfo();
MFI = MF.getFrameInfo();
MRI = &MF.getRegInfo();
+ SIs = &getAnalysis<SlotIndexes>();
LIs = &getAnalysis<LiveIntervals>();
LSs = &getAnalysis<LiveStacks>();
+ VRM = &getAnalysis<VirtRegMap>();
bool MadeChange = false;
projects / oota-llvm.git / blobdiff