//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "splitter"
+#define DEBUG_TYPE "regalloc"
#include "SplitKit.h"
#include "LiveRangeEdit.h"
#include "VirtRegMap.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/CalcSpillWeights.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
AllowSplit("spiller-splits-edges",
cl::desc("Allow critical edge splitting during spilling"));
+STATISTIC(NumFinished, "Number of splits finished");
+STATISTIC(NumSimple, "Number of splits that were simple");
+
//===----------------------------------------------------------------------===//
// Split Analysis
//===----------------------------------------------------------------------===//
-SplitAnalysis::SplitAnalysis(const MachineFunction &mf,
+SplitAnalysis::SplitAnalysis(const VirtRegMap &vrm,
const LiveIntervals &lis,
const MachineLoopInfo &mli)
- : mf_(mf),
- lis_(lis),
- loops_(mli),
- tii_(*mf.getTarget().getInstrInfo()),
- curli_(0) {}
+ : MF(vrm.getMachineFunction()),
+ VRM(vrm),
+ LIS(lis),
+ Loops(mli),
+ TII(*MF.getTarget().getInstrInfo()),
+ CurLI(0) {}
void SplitAnalysis::clear() {
- usingInstrs_.clear();
- usingBlocks_.clear();
- usingLoops_.clear();
- curli_ = 0;
+ UseSlots.clear();
+ UsingInstrs.clear();
+ UsingBlocks.clear();
+ LiveBlocks.clear();
+ CurLI = 0;
}
bool SplitAnalysis::canAnalyzeBranch(const MachineBasicBlock *MBB) {
MachineBasicBlock *T, *F;
SmallVector<MachineOperand, 4> Cond;
- return !tii_.AnalyzeBranch(const_cast<MachineBasicBlock&>(*MBB), T, F, Cond);
+ return !TII.AnalyzeBranch(const_cast<MachineBasicBlock&>(*MBB), T, F, Cond);
}
-/// analyzeUses - Count instructions, basic blocks, and loops using curli.
+/// analyzeUses - Count instructions, basic blocks, and loops using CurLI.
void SplitAnalysis::analyzeUses() {
- const MachineRegisterInfo &MRI = mf_.getRegInfo();
- for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(curli_->reg);
- MachineInstr *MI = I.skipInstruction();) {
- if (MI->isDebugValue() || !usingInstrs_.insert(MI))
+ const MachineRegisterInfo &MRI = MF.getRegInfo();
+ for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(CurLI->reg),
+ E = MRI.reg_end(); I != E; ++I) {
+ MachineOperand &MO = I.getOperand();
+ if (MO.isUse() && MO.isUndef())
continue;
- MachineBasicBlock *MBB = MI->getParent();
- if (usingBlocks_[MBB]++)
+ MachineInstr *MI = MO.getParent();
+ if (MI->isDebugValue() || !UsingInstrs.insert(MI))
continue;
- for (MachineLoop *Loop = loops_.getLoopFor(MBB); Loop;
- Loop = Loop->getParentLoop())
- usingLoops_[Loop]++;
+ UseSlots.push_back(LIS.getInstructionIndex(MI).getDefIndex());
+ MachineBasicBlock *MBB = MI->getParent();
+ UsingBlocks[MBB]++;
}
- DEBUG(dbgs() << " counted "
- << usingInstrs_.size() << " instrs, "
- << usingBlocks_.size() << " blocks, "
- << usingLoops_.size() << " loops.\n");
-}
+ array_pod_sort(UseSlots.begin(), UseSlots.end());
-void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const {
- for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) {
- unsigned count = usingBlocks_.lookup(*I);
- OS << " BB#" << (*I)->getNumber();
- if (count)
- OS << '(' << count << ')';
+ // Compute per-live block info.
+ if (!calcLiveBlockInfo()) {
+ // FIXME: calcLiveBlockInfo found inconsistencies in the live range.
+ // I am looking at you, SimpleRegisterCoalescing!
+ DEBUG(dbgs() << "*** Fixing inconsistent live interval! ***\n");
+ const_cast<LiveIntervals&>(LIS)
+ .shrinkToUses(const_cast<LiveInterval*>(CurLI));
+ LiveBlocks.clear();
+ bool fixed = calcLiveBlockInfo();
+ (void)fixed;
+ assert(fixed && "Couldn't fix broken live interval");
}
-}
-// Get three sets of basic blocks surrounding a loop: Blocks inside the loop,
-// predecessor blocks, and exit blocks.
-void SplitAnalysis::getLoopBlocks(const MachineLoop *Loop, LoopBlocks &Blocks) {
- Blocks.clear();
-
- // Blocks in the loop.
- Blocks.Loop.insert(Loop->block_begin(), Loop->block_end());
-
- // Predecessor blocks.
- const MachineBasicBlock *Header = Loop->getHeader();
- for (MachineBasicBlock::const_pred_iterator I = Header->pred_begin(),
- E = Header->pred_end(); I != E; ++I)
- if (!Blocks.Loop.count(*I))
- Blocks.Preds.insert(*I);
-
- // Exit blocks.
- for (MachineLoop::block_iterator I = Loop->block_begin(),
- E = Loop->block_end(); I != E; ++I) {
- const MachineBasicBlock *MBB = *I;
- for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI)
- if (!Blocks.Loop.count(*SI))
- Blocks.Exits.insert(*SI);
- }
+ DEBUG(dbgs() << "Analyze counted "
+ << UsingInstrs.size() << " instrs, "
+ << UsingBlocks.size() << " blocks, "
+ << LiveBlocks.size() << " spanned.\n");
}
-void SplitAnalysis::print(const LoopBlocks &B, raw_ostream &OS) const {
- OS << "Loop:";
- print(B.Loop, OS);
- OS << ", preds:";
- print(B.Preds, OS);
- OS << ", exits:";
- print(B.Exits, OS);
-}
+/// calcLiveBlockInfo - Fill the LiveBlocks array with information about blocks
+/// where CurLI is live.
+bool SplitAnalysis::calcLiveBlockInfo() {
+ if (CurLI->empty())
+ return true;
-/// analyzeLoopPeripheralUse - Return an enum describing how curli_ is used in
-/// and around the Loop.
-SplitAnalysis::LoopPeripheralUse SplitAnalysis::
-analyzeLoopPeripheralUse(const SplitAnalysis::LoopBlocks &Blocks) {
- LoopPeripheralUse use = ContainedInLoop;
- for (BlockCountMap::iterator I = usingBlocks_.begin(), E = usingBlocks_.end();
- I != E; ++I) {
- const MachineBasicBlock *MBB = I->first;
- // Is this a peripheral block?
- if (use < MultiPeripheral &&
- (Blocks.Preds.count(MBB) || Blocks.Exits.count(MBB))) {
- if (I->second > 1) use = MultiPeripheral;
- else use = SinglePeripheral;
- continue;
- }
- // Is it a loop block?
- if (Blocks.Loop.count(MBB))
- continue;
- // It must be an unrelated block.
- DEBUG(dbgs() << ", outside: BB#" << MBB->getNumber());
- return OutsideLoop;
- }
- return use;
-}
+ LiveInterval::const_iterator LVI = CurLI->begin();
+ LiveInterval::const_iterator LVE = CurLI->end();
-/// getCriticalExits - It may be necessary to partially break critical edges
-/// leaving the loop if an exit block has predecessors from outside the loop
-/// periphery.
-void SplitAnalysis::getCriticalExits(const SplitAnalysis::LoopBlocks &Blocks,
- BlockPtrSet &CriticalExits) {
- CriticalExits.clear();
-
- // A critical exit block has curli live-in, and has a predecessor that is not
- // in the loop nor a loop predecessor. For such an exit block, the edges
- // carrying the new variable must be moved to a new pre-exit block.
- for (BlockPtrSet::iterator I = Blocks.Exits.begin(), E = Blocks.Exits.end();
- I != E; ++I) {
- const MachineBasicBlock *Exit = *I;
- // A single-predecessor exit block is definitely not a critical edge.
- if (Exit->pred_size() == 1)
- continue;
- // This exit may not have curli live in at all. No need to split.
- if (!lis_.isLiveInToMBB(*curli_, Exit))
- continue;
- // Does this exit block have a predecessor that is not a loop block or loop
- // predecessor?
- for (MachineBasicBlock::const_pred_iterator PI = Exit->pred_begin(),
- PE = Exit->pred_end(); PI != PE; ++PI) {
- const MachineBasicBlock *Pred = *PI;
- if (Blocks.Loop.count(Pred) || Blocks.Preds.count(Pred))
- continue;
- // This is a critical exit block, and we need to split the exit edge.
- CriticalExits.insert(Exit);
- break;
- }
- }
-}
+ SmallVectorImpl<SlotIndex>::const_iterator UseI, UseE;
+ UseI = UseSlots.begin();
+ UseE = UseSlots.end();
-void SplitAnalysis::getCriticalPreds(const SplitAnalysis::LoopBlocks &Blocks,
- BlockPtrSet &CriticalPreds) {
- CriticalPreds.clear();
-
- // A critical predecessor block has curli live-out, and has a successor that
- // has curli live-in and is not in the loop nor a loop exit block. For such a
- // predecessor block, we must carry the value in both the 'inside' and
- // 'outside' registers.
- for (BlockPtrSet::iterator I = Blocks.Preds.begin(), E = Blocks.Preds.end();
- I != E; ++I) {
- const MachineBasicBlock *Pred = *I;
- // Definitely not a critical edge.
- if (Pred->succ_size() == 1)
- continue;
- // This block may not have curli live out at all if there is a PHI.
- if (!lis_.isLiveOutOfMBB(*curli_, Pred))
- continue;
- // Does this block have a successor outside the loop?
- for (MachineBasicBlock::const_pred_iterator SI = Pred->succ_begin(),
- SE = Pred->succ_end(); SI != SE; ++SI) {
- const MachineBasicBlock *Succ = *SI;
- if (Blocks.Loop.count(Succ) || Blocks.Exits.count(Succ))
- continue;
- if (!lis_.isLiveInToMBB(*curli_, Succ))
- continue;
- // This is a critical predecessor block.
- CriticalPreds.insert(Pred);
- break;
+ // Loop over basic blocks where CurLI is live.
+ MachineFunction::iterator MFI = LIS.getMBBFromIndex(LVI->start);
+ for (;;) {
+ BlockInfo BI;
+ BI.MBB = MFI;
+ tie(BI.Start, BI.Stop) = LIS.getSlotIndexes()->getMBBRange(BI.MBB);
+
+ // The last split point is the latest possible insertion point that dominates
+ // all successor blocks. If interference reaches LastSplitPoint, it is not
+ // possible to insert a split or reload that makes CurLI live in the
+ // outgoing bundle.
+ MachineBasicBlock::iterator LSP = LIS.getLastSplitPoint(*CurLI, BI.MBB);
+ if (LSP == BI.MBB->end())
+ BI.LastSplitPoint = BI.Stop;
+ else
+ BI.LastSplitPoint = LIS.getInstructionIndex(LSP);
+
+ // LVI is the first live segment overlapping MBB.
+ BI.LiveIn = LVI->start <= BI.Start;
+ if (!BI.LiveIn)
+ BI.Def = LVI->start;
+
+ // Find the first and last uses in the block.
+ BI.Uses = hasUses(MFI);
+ if (BI.Uses && UseI != UseE) {
+ BI.FirstUse = *UseI;
+ assert(BI.FirstUse >= BI.Start);
+ do ++UseI;
+ while (UseI != UseE && *UseI < BI.Stop);
+ BI.LastUse = UseI[-1];
+ assert(BI.LastUse < BI.Stop);
}
- }
-}
-/// canSplitCriticalExits - Return true if it is possible to insert new exit
-/// blocks before the blocks in CriticalExits.
-bool
-SplitAnalysis::canSplitCriticalExits(const SplitAnalysis::LoopBlocks &Blocks,
- BlockPtrSet &CriticalExits) {
- // If we don't allow critical edge splitting, require no critical exits.
- if (!AllowSplit)
- return CriticalExits.empty();
-
- for (BlockPtrSet::iterator I = CriticalExits.begin(), E = CriticalExits.end();
- I != E; ++I) {
- const MachineBasicBlock *Succ = *I;
- // We want to insert a new pre-exit MBB before Succ, and change all the
- // in-loop blocks to branch to the pre-exit instead of Succ.
- // Check that all the in-loop predecessors can be changed.
- for (MachineBasicBlock::const_pred_iterator PI = Succ->pred_begin(),
- PE = Succ->pred_end(); PI != PE; ++PI) {
- const MachineBasicBlock *Pred = *PI;
- // The external predecessors won't be altered.
- if (!Blocks.Loop.count(Pred) && !Blocks.Preds.count(Pred))
- continue;
- if (!canAnalyzeBranch(Pred))
- return false;
+ // Look for gaps in the live range.
+ bool hasGap = false;
+ BI.LiveOut = true;
+ while (LVI->end < BI.Stop) {
+ SlotIndex LastStop = LVI->end;
+ if (++LVI == LVE || LVI->start >= BI.Stop) {
+ BI.Kill = LastStop;
+ BI.LiveOut = false;
+ break;
+ }
+ if (LastStop < LVI->start) {
+ hasGap = true;
+ BI.Kill = LastStop;
+ BI.Def = LVI->start;
+ }
}
- // If Succ's layout predecessor falls through, that too must be analyzable.
- // We need to insert the pre-exit block in the gap.
- MachineFunction::const_iterator MFI = Succ;
- if (MFI == mf_.begin())
- continue;
- if (!canAnalyzeBranch(--MFI))
+ // Don't set LiveThrough when the block has a gap.
+ BI.LiveThrough = !hasGap && BI.LiveIn && BI.LiveOut;
+ LiveBlocks.push_back(BI);
+
+ // FIXME: This should never happen. The live range stops or starts without a
+ // corresponding use. An earlier pass did something wrong.
+ if (!BI.LiveThrough && !BI.Uses)
return false;
+
+ // LVI is now at LVE or LVI->end >= Stop.
+ if (LVI == LVE)
+ break;
+
+ // Live segment ends exactly at Stop. Move to the next segment.
+ if (LVI->end == BI.Stop && ++LVI == LVE)
+ break;
+
+ // Pick the next basic block.
+ if (LVI->start < BI.Stop)
+ ++MFI;
+ else
+ MFI = LIS.getMBBFromIndex(LVI->start);
}
- // No problems found.
return true;
}
-void SplitAnalysis::analyze(const LiveInterval *li) {
- clear();
- curli_ = li;
- analyzeUses();
-}
-
-const MachineLoop *SplitAnalysis::getBestSplitLoop() {
- assert(curli_ && "Call analyze() before getBestSplitLoop");
- if (usingLoops_.empty())
- return 0;
+bool SplitAnalysis::isOriginalEndpoint(SlotIndex Idx) const {
+ unsigned OrigReg = VRM.getOriginal(CurLI->reg);
+ const LiveInterval &Orig = LIS.getInterval(OrigReg);
+ assert(!Orig.empty() && "Splitting empty interval?");
+ LiveInterval::const_iterator I = Orig.find(Idx);
- LoopPtrSet Loops;
- LoopBlocks Blocks;
- BlockPtrSet CriticalExits;
+ // Range containing Idx should begin at Idx.
+ if (I != Orig.end() && I->start <= Idx)
+ return I->start == Idx;
- // We split around loops where curli is used outside the periphery.
- for (LoopCountMap::const_iterator I = usingLoops_.begin(),
- E = usingLoops_.end(); I != E; ++I) {
- const MachineLoop *Loop = I->first;
- getLoopBlocks(Loop, Blocks);
- DEBUG({ dbgs() << " "; print(Blocks, dbgs()); });
+ // Range does not contain Idx, previous must end at Idx.
+ return I != Orig.begin() && (--I)->end == Idx;
+}
- switch(analyzeLoopPeripheralUse(Blocks)) {
- case OutsideLoop:
- break;
- case MultiPeripheral:
- // FIXME: We could split a live range with multiple uses in a peripheral
- // block and still make progress. However, it is possible that splitting
- // another live range will insert copies into a peripheral block, and
- // there is a small chance we can enter an infinity loop, inserting copies
- // forever.
- // For safety, stick to splitting live ranges with uses outside the
- // periphery.
- DEBUG(dbgs() << ": multiple peripheral uses\n");
- break;
- case ContainedInLoop:
- DEBUG(dbgs() << ": fully contained\n");
- continue;
- case SinglePeripheral:
- DEBUG(dbgs() << ": single peripheral use\n");
- continue;
- }
- // Will it be possible to split around this loop?
- getCriticalExits(Blocks, CriticalExits);
- DEBUG(dbgs() << ": " << CriticalExits.size() << " critical exits\n");
- if (!canSplitCriticalExits(Blocks, CriticalExits))
- continue;
- // This is a possible split.
- Loops.insert(Loop);
+void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const {
+ for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) {
+ unsigned count = UsingBlocks.lookup(*I);
+ OS << " BB#" << (*I)->getNumber();
+ if (count)
+ OS << '(' << count << ')';
}
+}
- DEBUG(dbgs() << " getBestSplitLoop found " << Loops.size()
- << " candidate loops.\n");
-
- if (Loops.empty())
- return 0;
-
- // Pick the earliest loop.
- // FIXME: Are there other heuristics to consider?
- const MachineLoop *Best = 0;
- SlotIndex BestIdx;
- for (LoopPtrSet::const_iterator I = Loops.begin(), E = Loops.end(); I != E;
- ++I) {
- SlotIndex Idx = lis_.getMBBStartIdx((*I)->getHeader());
- if (!Best || Idx < BestIdx)
- Best = *I, BestIdx = Idx;
- }
- DEBUG(dbgs() << " getBestSplitLoop found " << *Best);
- return Best;
+void SplitAnalysis::analyze(const LiveInterval *li) {
+ clear();
+ CurLI = li;
+ analyzeUses();
}
+
//===----------------------------------------------------------------------===//
-// LiveIntervalMap
+// Split Editor
//===----------------------------------------------------------------------===//
-// Work around the fact that the std::pair constructors are broken for pointer
-// pairs in some implementations. makeVV(x, 0) works.
-static inline std::pair<const VNInfo*, VNInfo*>
-makeVV(const VNInfo *a, VNInfo *b) {
- return std::make_pair(a, b);
-}
-
-void LiveIntervalMap::reset(LiveInterval *li) {
- li_ = li;
- valueMap_.clear();
- liveOutCache_.clear();
-}
+/// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
+SplitEditor::SplitEditor(SplitAnalysis &sa,
+ LiveIntervals &lis,
+ VirtRegMap &vrm,
+ MachineDominatorTree &mdt)
+ : SA(sa), LIS(lis), VRM(vrm),
+ MRI(vrm.getMachineFunction().getRegInfo()),
+ MDT(mdt),
+ TII(*vrm.getMachineFunction().getTarget().getInstrInfo()),
+ TRI(*vrm.getMachineFunction().getTarget().getRegisterInfo()),
+ Edit(0),
+ OpenIdx(0),
+ RegAssign(Allocator)
+{}
+
+void SplitEditor::reset(LiveRangeEdit &lre) {
+ Edit = &lre;
+ OpenIdx = 0;
+ RegAssign.clear();
+ Values.clear();
+
+ // We don't need to clear LiveOutCache, only LiveOutSeen entries are read.
+ LiveOutSeen.clear();
+
+ // We don't need an AliasAnalysis since we will only be performing
+ // cheap-as-a-copy remats anyway.
+ Edit->anyRematerializable(LIS, TII, 0);
+}
+
+void SplitEditor::dump() const {
+ if (RegAssign.empty()) {
+ dbgs() << " empty\n";
+ return;
+ }
-bool LiveIntervalMap::isComplexMapped(const VNInfo *ParentVNI) const {
- ValueMap::const_iterator i = valueMap_.find(ParentVNI);
- return i != valueMap_.end() && i->second == 0;
+ for (RegAssignMap::const_iterator I = RegAssign.begin(); I.valid(); ++I)
+ dbgs() << " [" << I.start() << ';' << I.stop() << "):" << I.value();
+ dbgs() << '\n';
}
-// defValue - Introduce a li_ def for ParentVNI that could be later than
-// ParentVNI->def.
-VNInfo *LiveIntervalMap::defValue(const VNInfo *ParentVNI, SlotIndex Idx) {
- assert(li_ && "call reset first");
+VNInfo *SplitEditor::defValue(unsigned RegIdx,
+ const VNInfo *ParentVNI,
+ SlotIndex Idx) {
assert(ParentVNI && "Mapping NULL value");
assert(Idx.isValid() && "Invalid SlotIndex");
- assert(parentli_.getVNInfoAt(Idx) == ParentVNI && "Bad ParentVNI");
+ assert(Edit->getParent().getVNInfoAt(Idx) == ParentVNI && "Bad Parent VNI");
+ LiveInterval *LI = Edit->get(RegIdx);
// Create a new value.
- VNInfo *VNI = li_->getNextValue(Idx, 0, lis_.getVNInfoAllocator());
-
- // Preserve the PHIDef bit.
- if (ParentVNI->isPHIDef() && Idx == ParentVNI->def)
- VNI->setIsPHIDef(true);
+ VNInfo *VNI = LI->getNextValue(Idx, 0, LIS.getVNInfoAllocator());
// Use insert for lookup, so we can add missing values with a second lookup.
- std::pair<ValueMap::iterator,bool> InsP =
- valueMap_.insert(makeVV(ParentVNI, Idx == ParentVNI->def ? VNI : 0));
+ std::pair<ValueMap::iterator, bool> InsP =
+ Values.insert(std::make_pair(std::make_pair(RegIdx, ParentVNI->id), VNI));
+
+ // This was the first time (RegIdx, ParentVNI) was mapped.
+ // Keep it as a simple def without any liveness.
+ if (InsP.second)
+ return VNI;
- // This is now a complex def. Mark with a NULL in valueMap.
- if (!InsP.second)
+ // If the previous value was a simple mapping, add liveness for it now.
+ if (VNInfo *OldVNI = InsP.first->second) {
+ SlotIndex Def = OldVNI->def;
+ LI->addRange(LiveRange(Def, Def.getNextSlot(), OldVNI));
+ // No longer a simple mapping.
InsP.first->second = 0;
+ }
+
+ // This is a complex mapping, add liveness for VNI
+ SlotIndex Def = VNI->def;
+ LI->addRange(LiveRange(Def, Def.getNextSlot(), VNI));
return VNI;
}
-
-// mapValue - Find the mapped value for ParentVNI at Idx.
-// Potentially create phi-def values.
-VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx,
- bool *simple) {
- assert(li_ && "call reset first");
+void SplitEditor::markComplexMapped(unsigned RegIdx, const VNInfo *ParentVNI) {
assert(ParentVNI && "Mapping NULL value");
- assert(Idx.isValid() && "Invalid SlotIndex");
- assert(parentli_.getVNInfoAt(Idx) == ParentVNI && "Bad ParentVNI");
+ VNInfo *&VNI = Values[std::make_pair(RegIdx, ParentVNI->id)];
- // Use insert for lookup, so we can add missing values with a second lookup.
- std::pair<ValueMap::iterator,bool> InsP =
- valueMap_.insert(makeVV(ParentVNI, 0));
-
- // This was an unknown value. Create a simple mapping.
- if (InsP.second) {
- if (simple) *simple = true;
- return InsP.first->second = li_->createValueCopy(ParentVNI,
- lis_.getVNInfoAllocator());
- }
+ // ParentVNI was either unmapped or already complex mapped. Either way.
+ if (!VNI)
+ return;
- // This was a simple mapped value.
- if (InsP.first->second) {
- if (simple) *simple = true;
- return InsP.first->second;
- }
+ // This was previously a single mapping. Make sure the old def is represented
+ // by a trivial live range.
+ SlotIndex Def = VNI->def;
+ Edit->get(RegIdx)->addRange(LiveRange(Def, Def.getNextSlot(), VNI));
+ VNI = 0;
+}
- // This is a complex mapped value. There may be multiple defs, and we may need
- // to create phi-defs.
- if (simple) *simple = false;
- MachineBasicBlock *IdxMBB = lis_.getMBBFromIndex(Idx);
+// extendRange - Extend the live range to reach Idx.
+// Potentially create phi-def values.
+void SplitEditor::extendRange(unsigned RegIdx, SlotIndex Idx) {
+ assert(Idx.isValid() && "Invalid SlotIndex");
+ MachineBasicBlock *IdxMBB = LIS.getMBBFromIndex(Idx);
assert(IdxMBB && "No MBB at Idx");
+ LiveInterval *LI = Edit->get(RegIdx);
// Is there a def in the same MBB we can extend?
- if (VNInfo *VNI = extendTo(IdxMBB, Idx))
- return VNI;
+ if (LI->extendInBlock(LIS.getMBBStartIdx(IdxMBB), Idx))
+ return;
// Now for the fun part. We know that ParentVNI potentially has multiple defs,
// and we may need to create even more phi-defs to preserve VNInfo SSA form.
// Perform a search for all predecessor blocks where we know the dominating
// VNInfo. Insert phi-def VNInfos along the path back to IdxMBB.
- DEBUG(dbgs() << "\n Reaching defs for BB#" << IdxMBB->getNumber()
- << " at " << Idx << " in " << *li_ << '\n');
- // Blocks where li_ should be live-in.
+ // Initialize the live-out cache the first time it is needed.
+ if (LiveOutSeen.empty()) {
+ unsigned N = VRM.getMachineFunction().getNumBlockIDs();
+ LiveOutSeen.resize(N);
+ LiveOutCache.resize(N);
+ }
+
+ // Blocks where LI should be live-in.
SmallVector<MachineDomTreeNode*, 16> LiveIn;
- LiveIn.push_back(mdt_[IdxMBB]);
+ LiveIn.push_back(MDT[IdxMBB]);
+
+ // Remember if we have seen more than one value.
+ bool UniqueVNI = true;
+ VNInfo *IdxVNI = 0;
- // Using liveOutCache_ as a visited set, perform a BFS for all reaching defs.
+ // Using LiveOutCache as a visited set, perform a BFS for all reaching defs.
for (unsigned i = 0; i != LiveIn.size(); ++i) {
MachineBasicBlock *MBB = LiveIn[i]->getBlock();
+ assert(!MBB->pred_empty() && "Value live-in to entry block?");
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI) {
MachineBasicBlock *Pred = *PI;
+ LiveOutPair &LOP = LiveOutCache[Pred];
+
// Is this a known live-out block?
- std::pair<LiveOutMap::iterator,bool> LOIP =
- liveOutCache_.insert(std::make_pair(Pred, LiveOutPair()));
- // Yes, we have been here before.
- if (!LOIP.second) {
- DEBUG(if (VNInfo *VNI = LOIP.first->second.first)
- dbgs() << " known valno #" << VNI->id
- << " at BB#" << Pred->getNumber() << '\n');
+ if (LiveOutSeen.test(Pred->getNumber())) {
+ if (VNInfo *VNI = LOP.first) {
+ if (IdxVNI && IdxVNI != VNI)
+ UniqueVNI = false;
+ IdxVNI = VNI;
+ }
continue;
}
+ // First time. LOP is garbage and must be cleared below.
+ LiveOutSeen.set(Pred->getNumber());
+
// Does Pred provide a live-out value?
- SlotIndex Last = lis_.getMBBEndIdx(Pred).getPrevSlot();
- if (VNInfo *VNI = extendTo(Pred, Last)) {
- MachineBasicBlock *DefMBB = lis_.getMBBFromIndex(VNI->def);
- DEBUG(dbgs() << " found valno #" << VNI->id
- << " from BB#" << DefMBB->getNumber()
- << " at BB#" << Pred->getNumber() << '\n');
- LiveOutPair &LOP = LOIP.first->second;
- LOP.first = VNI;
- LOP.second = mdt_[DefMBB];
+ SlotIndex Start, Last;
+ tie(Start, Last) = LIS.getSlotIndexes()->getMBBRange(Pred);
+ Last = Last.getPrevSlot();
+ VNInfo *VNI = LI->extendInBlock(Start, Last);
+ LOP.first = VNI;
+ if (VNI) {
+ LOP.second = MDT[LIS.getMBBFromIndex(VNI->def)];
+ if (IdxVNI && IdxVNI != VNI)
+ UniqueVNI = false;
+ IdxVNI = VNI;
continue;
}
+ LOP.second = 0;
+
// No, we need a live-in value for Pred as well
if (Pred != IdxMBB)
- LiveIn.push_back(mdt_[Pred]);
+ LiveIn.push_back(MDT[Pred]);
+ else
+ UniqueVNI = false; // Loopback to IdxMBB, ask updateSSA() for help.
}
}
// We may need to add phi-def values to preserve the SSA form.
+ if (UniqueVNI) {
+ LiveOutPair LOP(IdxVNI, MDT[LIS.getMBBFromIndex(IdxVNI->def)]);
+ // Update LiveOutCache, but skip IdxMBB at LiveIn[0].
+ for (unsigned i = 1, e = LiveIn.size(); i != e; ++i)
+ LiveOutCache[LiveIn[i]->getBlock()] = LOP;
+ } else
+ IdxVNI = updateSSA(RegIdx, LiveIn, Idx, IdxMBB);
+
+ // Since we went through the trouble of a full BFS visiting all reaching defs,
+ // the values in LiveIn are now accurate. No more phi-defs are needed
+ // for these blocks, so we can color the live ranges.
+ for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) {
+ MachineBasicBlock *MBB = LiveIn[i]->getBlock();
+ SlotIndex Start = LIS.getMBBStartIdx(MBB);
+ VNInfo *VNI = LiveOutCache[MBB].first;
+
+ // Anything in LiveIn other than IdxMBB is live-through.
+ // In IdxMBB, we should stop at Idx unless the same value is live-out.
+ if (MBB == IdxMBB && IdxVNI != VNI)
+ LI->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI));
+ else
+ LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
+ }
+}
+
+VNInfo *SplitEditor::updateSSA(unsigned RegIdx,
+ SmallVectorImpl<MachineDomTreeNode*> &LiveIn,
+ SlotIndex Idx,
+ const MachineBasicBlock *IdxMBB) {
// This is essentially the same iterative algorithm that SSAUpdater uses,
// except we already have a dominator tree, so we don't have to recompute it.
+ LiveInterval *LI = Edit->get(RegIdx);
VNInfo *IdxVNI = 0;
unsigned Changes;
do {
Changes = 0;
- DEBUG(dbgs() << " Iterating over " << LiveIn.size() << " blocks.\n");
- // Propagate live-out values down the dominator tree, inserting phi-defs when
- // necessary. Since LiveIn was created by a BFS, going backwards makes it more
- // likely for us to visit immediate dominators before their children.
+ // Propagate live-out values down the dominator tree, inserting phi-defs
+ // when necessary. Since LiveIn was created by a BFS, going backwards makes
+ // it more likely for us to visit immediate dominators before their
+ // children.
for (unsigned i = LiveIn.size(); i; --i) {
MachineDomTreeNode *Node = LiveIn[i-1];
MachineBasicBlock *MBB = Node->getBlock();
MachineDomTreeNode *IDom = Node->getIDom();
LiveOutPair IDomValue;
+
// We need a live-in value to a block with no immediate dominator?
// This is probably an unreachable block that has survived somehow.
- bool needPHI = !IDom;
-
- // Get the IDom live-out value.
- if (!needPHI) {
- LiveOutMap::iterator I = liveOutCache_.find(IDom->getBlock());
- if (I != liveOutCache_.end())
- IDomValue = I->second;
- else
- // If IDom is outside our set of live-out blocks, there must be new
- // defs, and we need a phi-def here.
- needPHI = true;
- }
+ bool needPHI = !IDom || !LiveOutSeen.test(IDom->getBlock()->getNumber());
// IDom dominates all of our predecessors, but it may not be the immediate
// dominator. Check if any of them have live-out values that are properly
// dominated by IDom. If so, we need a phi-def here.
if (!needPHI) {
+ IDomValue = LiveOutCache[IDom->getBlock()];
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI) {
- LiveOutPair Value = liveOutCache_[*PI];
+ LiveOutPair Value = LiveOutCache[*PI];
if (!Value.first || Value.first == IDomValue.first)
continue;
// This predecessor is carrying something other than IDomValue.
// It could be because IDomValue hasn't propagated yet, or it could be
// because MBB is in the dominance frontier of that value.
- if (mdt_.dominates(IDom, Value.second)) {
+ if (MDT.dominates(IDom, Value.second)) {
needPHI = true;
break;
}
// Create a phi-def if required.
if (needPHI) {
++Changes;
- SlotIndex Start = lis_.getMBBStartIdx(MBB);
- VNInfo *VNI = li_->getNextValue(Start, 0, lis_.getVNInfoAllocator());
+ SlotIndex Start = LIS.getMBBStartIdx(MBB);
+ VNInfo *VNI = LI->getNextValue(Start, 0, LIS.getVNInfoAllocator());
VNI->setIsPHIDef(true);
- DEBUG(dbgs() << " - BB#" << MBB->getNumber()
- << " phi-def #" << VNI->id << " at " << Start << '\n');
- // We no longer need li_ to be live-in.
+ // We no longer need LI to be live-in.
LiveIn.erase(LiveIn.begin()+(i-1));
// Blocks in LiveIn are either IdxMBB, or have a value live-through.
if (MBB == IdxMBB)
IdxVNI = VNI;
// Check if we need to update live-out info.
- LiveOutMap::iterator I = liveOutCache_.find(MBB);
- if (I == liveOutCache_.end() || I->second.second == Node) {
+ LiveOutPair &LOP = LiveOutCache[MBB];
+ if (LOP.second == Node || !LiveOutSeen.test(MBB->getNumber())) {
// We already have a live-out defined in MBB, so this must be IdxMBB.
assert(MBB == IdxMBB && "Adding phi-def to known live-out");
- li_->addRange(LiveRange(Start, Idx.getNextSlot(), VNI));
+ LI->addRange(LiveRange(Start, Idx.getNextSlot(), VNI));
} else {
// This phi-def is also live-out, so color the whole block.
- li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI));
- I->second = LiveOutPair(VNI, Node);
+ LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
+ LOP = LiveOutPair(VNI, Node);
}
} else if (IDomValue.first) {
// No phi-def here. Remember incoming value for IdxMBB.
- if (MBB == IdxMBB)
+ if (MBB == IdxMBB) {
IdxVNI = IDomValue.first;
+ // IdxMBB need not be live-out.
+ if (!LiveOutSeen.test(MBB->getNumber()))
+ continue;
+ }
+ assert(LiveOutSeen.test(MBB->getNumber()) && "Expected live-out block");
// Propagate IDomValue if needed:
// MBB is live-out and doesn't define its own value.
- LiveOutMap::iterator I = liveOutCache_.find(MBB);
- if (I != liveOutCache_.end() && I->second.second != Node &&
- I->second.first != IDomValue.first) {
+ LiveOutPair &LOP = LiveOutCache[MBB];
+ if (LOP.second != Node && LOP.first != IDomValue.first) {
++Changes;
- I->second = IDomValue;
- DEBUG(dbgs() << " - BB#" << MBB->getNumber()
- << " idom valno #" << IDomValue.first->id
- << " from BB#" << IDom->getBlock()->getNumber() << '\n');
+ LOP = IDomValue;
}
}
}
- DEBUG(dbgs() << " - made " << Changes << " changes.\n");
} while (Changes);
assert(IdxVNI && "Didn't find value for Idx");
-
-#ifndef NDEBUG
- // Check the liveOutCache_ invariants.
- for (LiveOutMap::iterator I = liveOutCache_.begin(), E = liveOutCache_.end();
- I != E; ++I) {
- assert(I->first && "Null MBB entry in cache");
- assert(I->second.first && "Null VNInfo in cache");
- assert(I->second.second && "Null DomTreeNode in cache");
- if (I->second.second->getBlock() == I->first)
- continue;
- for (MachineBasicBlock::pred_iterator PI = I->first->pred_begin(),
- PE = I->first->pred_end(); PI != PE; ++PI)
- assert(liveOutCache_.lookup(*PI) == I->second && "Bad invariant");
- }
-#endif
-
- // Since we went through the trouble of a full BFS visiting all reaching defs,
- // the values in LiveIn are now accurate. No more phi-defs are needed
- // for these blocks, so we can color the live ranges.
- // This makes the next mapValue call much faster.
- for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) {
- MachineBasicBlock *MBB = LiveIn[i]->getBlock();
- SlotIndex Start = lis_.getMBBStartIdx(MBB);
- if (MBB == IdxMBB) {
- li_->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI));
- continue;
- }
- // Anything in LiveIn other than IdxMBB is live-through.
- VNInfo *VNI = liveOutCache_.lookup(MBB).first;
- assert(VNI && "Missing block value");
- li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI));
- }
-
return IdxVNI;
}
-// extendTo - Find the last li_ value defined in MBB at or before Idx. The
-// parentli_ is assumed to be live at Idx. Extend the live range to Idx.
-// Return the found VNInfo, or NULL.
-VNInfo *LiveIntervalMap::extendTo(const MachineBasicBlock *MBB, SlotIndex Idx) {
- assert(li_ && "call reset first");
- LiveInterval::iterator I = std::upper_bound(li_->begin(), li_->end(), Idx);
- if (I == li_->begin())
- return 0;
- --I;
- if (I->end <= lis_.getMBBStartIdx(MBB))
- return 0;
- if (I->end <= Idx)
- I->end = Idx.getNextSlot();
- return I->valno;
-}
-
-// addSimpleRange - Add a simple range from parentli_ to li_.
-// ParentVNI must be live in the [Start;End) interval.
-void LiveIntervalMap::addSimpleRange(SlotIndex Start, SlotIndex End,
- const VNInfo *ParentVNI) {
- assert(li_ && "call reset first");
- bool simple;
- VNInfo *VNI = mapValue(ParentVNI, Start, &simple);
- // A simple mapping is easy.
- if (simple) {
- li_->addRange(LiveRange(Start, End, VNI));
- return;
- }
-
- // ParentVNI is a complex value. We must map per MBB.
- MachineFunction::iterator MBB = lis_.getMBBFromIndex(Start);
- MachineFunction::iterator MBBE = lis_.getMBBFromIndex(End.getPrevSlot());
-
- if (MBB == MBBE) {
- li_->addRange(LiveRange(Start, End, VNI));
- return;
- }
-
- // First block.
- li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI));
-
- // Run sequence of full blocks.
- for (++MBB; MBB != MBBE; ++MBB) {
- Start = lis_.getMBBStartIdx(MBB);
- li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB),
- mapValue(ParentVNI, Start)));
- }
-
- // Final block.
- Start = lis_.getMBBStartIdx(MBB);
- if (Start != End)
- li_->addRange(LiveRange(Start, End, mapValue(ParentVNI, Start)));
-}
-
-/// addRange - Add live ranges to li_ where [Start;End) intersects parentli_.
-/// All needed values whose def is not inside [Start;End) must be defined
-/// beforehand so mapValue will work.
-void LiveIntervalMap::addRange(SlotIndex Start, SlotIndex End) {
- assert(li_ && "call reset first");
- LiveInterval::const_iterator B = parentli_.begin(), E = parentli_.end();
- LiveInterval::const_iterator I = std::lower_bound(B, E, Start);
-
- // Check if --I begins before Start and overlaps.
- if (I != B) {
- --I;
- if (I->end > Start)
- addSimpleRange(Start, std::min(End, I->end), I->valno);
- ++I;
- }
-
- // The remaining ranges begin after Start.
- for (;I != E && I->start < End; ++I)
- addSimpleRange(I->start, std::min(End, I->end), I->valno);
-}
-
-VNInfo *LiveIntervalMap::defByCopy(const VNInfo *ParentVNI,
+VNInfo *SplitEditor::defFromParent(unsigned RegIdx,
+ VNInfo *ParentVNI,
+ SlotIndex UseIdx,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) {
- const TargetInstrDesc &TID = MBB.getParent()->getTarget().getInstrInfo()->
- get(TargetOpcode::COPY);
- MachineInstr *MI = BuildMI(MBB, I, DebugLoc(), TID, li_->reg)
- .addReg(parentli_.reg);
- SlotIndex DefIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
- VNInfo *VNI = defValue(ParentVNI, DefIdx);
- VNI->setCopy(MI);
- li_->addRange(LiveRange(DefIdx, DefIdx.getNextSlot(), VNI));
+ MachineInstr *CopyMI = 0;
+ SlotIndex Def;
+ LiveInterval *LI = Edit->get(RegIdx);
+
+ // Attempt cheap-as-a-copy rematerialization.
+ LiveRangeEdit::Remat RM(ParentVNI);
+ if (Edit->canRematerializeAt(RM, UseIdx, true, LIS)) {
+ Def = Edit->rematerializeAt(MBB, I, LI->reg, RM, LIS, TII, TRI);
+ } else {
+ // Can't remat, just insert a copy from parent.
+ CopyMI = BuildMI(MBB, I, DebugLoc(), TII.get(TargetOpcode::COPY), LI->reg)
+ .addReg(Edit->getReg());
+ Def = LIS.InsertMachineInstrInMaps(CopyMI).getDefIndex();
+ }
+
+ // Define the value in Reg.
+ VNInfo *VNI = defValue(RegIdx, ParentVNI, Def);
+ VNI->setCopy(CopyMI);
return VNI;
}
-//===----------------------------------------------------------------------===//
-// Split Editor
-//===----------------------------------------------------------------------===//
-
-/// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
-SplitEditor::SplitEditor(SplitAnalysis &sa,
- LiveIntervals &lis,
- VirtRegMap &vrm,
- MachineDominatorTree &mdt,
- LiveRangeEdit &edit)
- : sa_(sa), lis_(lis), vrm_(vrm),
- mri_(vrm.getMachineFunction().getRegInfo()),
- tii_(*vrm.getMachineFunction().getTarget().getInstrInfo()),
- edit_(edit),
- dupli_(lis_, mdt, edit.getParent()),
- openli_(lis_, mdt, edit.getParent())
-{
-}
-
-bool SplitEditor::intervalsLiveAt(SlotIndex Idx) const {
- for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I)
- if (*I != dupli_.getLI() && (*I)->liveAt(Idx))
- return true;
- return false;
-}
-
/// Create a new virtual register and live interval.
void SplitEditor::openIntv() {
- assert(!openli_.getLI() && "Previous LI not closed before openIntv");
+ assert(!OpenIdx && "Previous LI not closed before openIntv");
- if (!dupli_.getLI())
- dupli_.reset(&edit_.create(mri_, lis_, vrm_));
+ // Create the complement as index 0.
+ if (Edit->empty())
+ Edit->create(LIS, VRM);
- openli_.reset(&edit_.create(mri_, lis_, vrm_));
+ // Create the open interval.
+ OpenIdx = Edit->size();
+ Edit->create(LIS, VRM);
}
-/// enterIntvBefore - Enter openli before the instruction at Idx. If curli is
-/// not live before Idx, a COPY is not inserted.
-void SplitEditor::enterIntvBefore(SlotIndex Idx) {
- assert(openli_.getLI() && "openIntv not called before enterIntvBefore");
+SlotIndex SplitEditor::enterIntvBefore(SlotIndex Idx) {
+ assert(OpenIdx && "openIntv not called before enterIntvBefore");
DEBUG(dbgs() << " enterIntvBefore " << Idx);
- VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Idx.getUseIndex());
+ Idx = Idx.getBaseIndex();
+ VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
if (!ParentVNI) {
DEBUG(dbgs() << ": not live\n");
- return;
+ return Idx;
}
- DEBUG(dbgs() << ": valno " << ParentVNI->id);
- truncatedValues.insert(ParentVNI);
- MachineInstr *MI = lis_.getInstructionFromIndex(Idx);
+ DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
+ MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
assert(MI && "enterIntvBefore called with invalid index");
- VNInfo *VNI = openli_.defByCopy(ParentVNI, *MI->getParent(), MI);
- openli_.getLI()->addRange(LiveRange(VNI->def, Idx.getDefIndex(), VNI));
- DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
+
+ VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Idx, *MI->getParent(), MI);
+ return VNI->def;
}
-/// enterIntvAtEnd - Enter openli at the end of MBB.
-void SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) {
- assert(openli_.getLI() && "openIntv not called before enterIntvAtEnd");
- SlotIndex End = lis_.getMBBEndIdx(&MBB);
- DEBUG(dbgs() << " enterIntvAtEnd BB#" << MBB.getNumber() << ", " << End);
- VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(End.getPrevSlot());
+SlotIndex SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) {
+ assert(OpenIdx && "openIntv not called before enterIntvAtEnd");
+ SlotIndex End = LIS.getMBBEndIdx(&MBB);
+ SlotIndex Last = End.getPrevSlot();
+ DEBUG(dbgs() << " enterIntvAtEnd BB#" << MBB.getNumber() << ", " << Last);
+ VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Last);
if (!ParentVNI) {
DEBUG(dbgs() << ": not live\n");
- return;
+ return End;
}
DEBUG(dbgs() << ": valno " << ParentVNI->id);
- truncatedValues.insert(ParentVNI);
- VNInfo *VNI = openli_.defByCopy(ParentVNI, MBB, MBB.getFirstTerminator());
- // Make sure openli is live out of MBB.
- openli_.getLI()->addRange(LiveRange(VNI->def, End, VNI));
- DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
+ VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Last, MBB,
+ LIS.getLastSplitPoint(Edit->getParent(), &MBB));
+ RegAssign.insert(VNI->def, End, OpenIdx);
+ DEBUG(dump());
+ return VNI->def;
}
-/// useIntv - indicate that all instructions in MBB should use openli.
+/// useIntv - indicate that all instructions in MBB should use OpenLI.
void SplitEditor::useIntv(const MachineBasicBlock &MBB) {
- useIntv(lis_.getMBBStartIdx(&MBB), lis_.getMBBEndIdx(&MBB));
+ useIntv(LIS.getMBBStartIdx(&MBB), LIS.getMBBEndIdx(&MBB));
}
void SplitEditor::useIntv(SlotIndex Start, SlotIndex End) {
- assert(openli_.getLI() && "openIntv not called before useIntv");
- openli_.addRange(Start, End);
- DEBUG(dbgs() << " use [" << Start << ';' << End << "): "
- << *openli_.getLI() << '\n');
+ assert(OpenIdx && "openIntv not called before useIntv");
+ DEBUG(dbgs() << " useIntv [" << Start << ';' << End << "):");
+ RegAssign.insert(Start, End, OpenIdx);
+ DEBUG(dump());
}
-/// leaveIntvAfter - Leave openli after the instruction at Idx.
-void SplitEditor::leaveIntvAfter(SlotIndex Idx) {
- assert(openli_.getLI() && "openIntv not called before leaveIntvAfter");
+SlotIndex SplitEditor::leaveIntvAfter(SlotIndex Idx) {
+ assert(OpenIdx && "openIntv not called before leaveIntvAfter");
DEBUG(dbgs() << " leaveIntvAfter " << Idx);
// The interval must be live beyond the instruction at Idx.
- VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Idx.getBoundaryIndex());
+ Idx = Idx.getBoundaryIndex();
+ VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
if (!ParentVNI) {
DEBUG(dbgs() << ": not live\n");
- return;
+ return Idx.getNextSlot();
}
- DEBUG(dbgs() << ": valno " << ParentVNI->id);
+ DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
- MachineBasicBlock::iterator MII = lis_.getInstructionFromIndex(Idx);
- MachineBasicBlock *MBB = MII->getParent();
- VNInfo *VNI = dupli_.defByCopy(ParentVNI, *MBB, llvm::next(MII));
+ MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
+ assert(MI && "No instruction at index");
+ VNInfo *VNI = defFromParent(0, ParentVNI, Idx, *MI->getParent(),
+ llvm::next(MachineBasicBlock::iterator(MI)));
+ return VNI->def;
+}
- // Finally we must make sure that openli is properly extended from Idx to the
- // new copy.
- openli_.addSimpleRange(Idx.getBoundaryIndex(), VNI->def, ParentVNI);
- DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
+SlotIndex SplitEditor::leaveIntvBefore(SlotIndex Idx) {
+ assert(OpenIdx && "openIntv not called before leaveIntvBefore");
+ DEBUG(dbgs() << " leaveIntvBefore " << Idx);
+
+ // The interval must be live into the instruction at Idx.
+ Idx = Idx.getBoundaryIndex();
+ VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
+ if (!ParentVNI) {
+ DEBUG(dbgs() << ": not live\n");
+ return Idx.getNextSlot();
+ }
+ DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
+
+ MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
+ assert(MI && "No instruction at index");
+ VNInfo *VNI = defFromParent(0, ParentVNI, Idx, *MI->getParent(), MI);
+ return VNI->def;
}
-/// leaveIntvAtTop - Leave the interval at the top of MBB.
-/// Currently, only one value can leave the interval.
-void SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) {
- assert(openli_.getLI() && "openIntv not called before leaveIntvAtTop");
- SlotIndex Start = lis_.getMBBStartIdx(&MBB);
+SlotIndex SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) {
+ assert(OpenIdx && "openIntv not called before leaveIntvAtTop");
+ SlotIndex Start = LIS.getMBBStartIdx(&MBB);
DEBUG(dbgs() << " leaveIntvAtTop BB#" << MBB.getNumber() << ", " << Start);
- VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Start);
+ VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Start);
if (!ParentVNI) {
DEBUG(dbgs() << ": not live\n");
- return;
+ return Start;
}
- // We are going to insert a back copy, so we must have a dupli_.
- VNInfo *VNI = dupli_.defByCopy(ParentVNI, MBB,
- MBB.SkipPHIsAndLabels(MBB.begin()));
+ VNInfo *VNI = defFromParent(0, ParentVNI, Start, MBB,
+ MBB.SkipPHIsAndLabels(MBB.begin()));
+ RegAssign.insert(Start, VNI->def, OpenIdx);
+ DEBUG(dump());
+ return VNI->def;
+}
+
+void SplitEditor::overlapIntv(SlotIndex Start, SlotIndex End) {
+ assert(OpenIdx && "openIntv not called before overlapIntv");
+ const VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Start);
+ assert(ParentVNI == Edit->getParent().getVNInfoAt(End.getPrevSlot()) &&
+ "Parent changes value in extended range");
+ assert(LIS.getMBBFromIndex(Start) == LIS.getMBBFromIndex(End) &&
+ "Range cannot span basic blocks");
- // Finally we must make sure that openli is properly extended from Start to
- // the new copy.
- openli_.addSimpleRange(Start, VNI->def, ParentVNI);
- DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
+ // The complement interval will be extended as needed by extendRange().
+ markComplexMapped(0, ParentVNI);
+ DEBUG(dbgs() << " overlapIntv [" << Start << ';' << End << "):");
+ RegAssign.insert(Start, End, OpenIdx);
+ DEBUG(dump());
}
/// closeIntv - Indicate that we are done editing the currently open
/// LiveInterval, and ranges can be trimmed.
void SplitEditor::closeIntv() {
- assert(openli_.getLI() && "openIntv not called before closeIntv");
-
- DEBUG(dbgs() << " closeIntv cleaning up\n");
- DEBUG(dbgs() << " open " << *openli_.getLI() << '\n');
- openli_.reset(0);
+ assert(OpenIdx && "openIntv not called before closeIntv");
+ OpenIdx = 0;
+}
+
+/// transferSimpleValues - Transfer all simply defined values to the new live
+/// ranges.
+/// Values that were rematerialized or that have multiple defs are left alone.
+bool SplitEditor::transferSimpleValues() {
+ bool Skipped = false;
+ RegAssignMap::const_iterator AssignI = RegAssign.begin();
+ for (LiveInterval::const_iterator ParentI = Edit->getParent().begin(),
+ ParentE = Edit->getParent().end(); ParentI != ParentE; ++ParentI) {
+ DEBUG(dbgs() << " blit " << *ParentI << ':');
+ VNInfo *ParentVNI = ParentI->valno;
+ // RegAssign has holes where RegIdx 0 should be used.
+ SlotIndex Start = ParentI->start;
+ AssignI.advanceTo(Start);
+ do {
+ unsigned RegIdx;
+ SlotIndex End = ParentI->end;
+ if (!AssignI.valid()) {
+ RegIdx = 0;
+ } else if (AssignI.start() <= Start) {
+ RegIdx = AssignI.value();
+ if (AssignI.stop() < End) {
+ End = AssignI.stop();
+ ++AssignI;
+ }
+ } else {
+ RegIdx = 0;
+ End = std::min(End, AssignI.start());
+ }
+ DEBUG(dbgs() << " [" << Start << ';' << End << ")=" << RegIdx);
+ if (VNInfo *VNI = Values.lookup(std::make_pair(RegIdx, ParentVNI->id))) {
+ DEBUG(dbgs() << ':' << VNI->id);
+ Edit->get(RegIdx)->addRange(LiveRange(Start, End, VNI));
+ } else
+ Skipped = true;
+ Start = End;
+ } while (Start != ParentI->end);
+ DEBUG(dbgs() << '\n');
+ }
+ return Skipped;
+}
+
+void SplitEditor::extendPHIKillRanges() {
+ // Extend live ranges to be live-out for successor PHI values.
+ for (LiveInterval::const_vni_iterator I = Edit->getParent().vni_begin(),
+ E = Edit->getParent().vni_end(); I != E; ++I) {
+ const VNInfo *PHIVNI = *I;
+ if (PHIVNI->isUnused() || !PHIVNI->isPHIDef())
+ continue;
+ unsigned RegIdx = RegAssign.lookup(PHIVNI->def);
+ MachineBasicBlock *MBB = LIS.getMBBFromIndex(PHIVNI->def);
+ for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ SlotIndex End = LIS.getMBBEndIdx(*PI).getPrevSlot();
+ // The predecessor may not have a live-out value. That is OK, like an
+ // undef PHI operand.
+ if (Edit->getParent().liveAt(End)) {
+ assert(RegAssign.lookup(End) == RegIdx &&
+ "Different register assignment in phi predecessor");
+ extendRange(RegIdx, End);
+ }
+ }
+ }
}
-/// rewrite - Rewrite all uses of reg to use the new registers.
-void SplitEditor::rewrite(unsigned reg) {
- for (MachineRegisterInfo::reg_iterator RI = mri_.reg_begin(reg),
- RE = mri_.reg_end(); RI != RE;) {
+/// rewriteAssigned - Rewrite all uses of Edit->getReg().
+void SplitEditor::rewriteAssigned(bool ExtendRanges) {
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Edit->getReg()),
+ RE = MRI.reg_end(); RI != RE;) {
MachineOperand &MO = RI.getOperand();
- unsigned OpNum = RI.getOperandNo();
MachineInstr *MI = MO.getParent();
++RI;
+ // LiveDebugVariables should have handled all DBG_VALUE instructions.
if (MI->isDebugValue()) {
DEBUG(dbgs() << "Zapping " << *MI);
- // FIXME: We can do much better with debug values.
MO.setReg(0);
continue;
}
- SlotIndex Idx = lis_.getInstructionIndex(MI);
- Idx = MO.isUse() ? Idx.getUseIndex() : Idx.getDefIndex();
- LiveInterval *LI = 0;
- for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E;
- ++I) {
- LiveInterval *testli = *I;
- if (testli->liveAt(Idx)) {
- LI = testli;
- break;
- }
+
+ // <undef> operands don't really read the register, so just assign them to
+ // the complement.
+ if (MO.isUse() && MO.isUndef()) {
+ MO.setReg(Edit->get(0)->reg);
+ continue;
}
- DEBUG(dbgs() << " rewr BB#" << MI->getParent()->getNumber() << '\t'<< Idx);
- assert(LI && "No register was live at use");
- MO.setReg(LI->reg);
- if (MO.isUse() && !MI->isRegTiedToDefOperand(OpNum))
- MO.setIsKill(LI->killedAt(Idx.getDefIndex()));
- DEBUG(dbgs() << '\t' << *MI);
- }
-}
-void
-SplitEditor::addTruncSimpleRange(SlotIndex Start, SlotIndex End, VNInfo *VNI) {
- // Build vector of iterator pairs from the intervals.
- typedef std::pair<LiveInterval::const_iterator,
- LiveInterval::const_iterator> IIPair;
- SmallVector<IIPair, 8> Iters;
- for (LiveRangeEdit::iterator LI = edit_.begin(), LE = edit_.end(); LI != LE;
- ++LI) {
- if (*LI == dupli_.getLI())
+ SlotIndex Idx = LIS.getInstructionIndex(MI);
+ if (MO.isDef())
+ Idx = MO.isEarlyClobber() ? Idx.getUseIndex() : Idx.getDefIndex();
+
+ // Rewrite to the mapped register at Idx.
+ unsigned RegIdx = RegAssign.lookup(Idx);
+ MO.setReg(Edit->get(RegIdx)->reg);
+ DEBUG(dbgs() << " rewr BB#" << MI->getParent()->getNumber() << '\t'
+ << Idx << ':' << RegIdx << '\t' << *MI);
+
+ // Extend liveness to Idx if the instruction reads reg.
+ if (!ExtendRanges)
continue;
- LiveInterval::const_iterator I = (*LI)->find(Start);
- LiveInterval::const_iterator E = (*LI)->end();
- if (I != E)
- Iters.push_back(std::make_pair(I, E));
- }
- SlotIndex sidx = Start;
- // Break [Start;End) into segments that don't overlap any intervals.
- for (;;) {
- SlotIndex next = sidx, eidx = End;
- // Find overlapping intervals.
- for (unsigned i = 0; i != Iters.size() && sidx < eidx; ++i) {
- LiveInterval::const_iterator I = Iters[i].first;
- // Interval I is overlapping [sidx;eidx). Trim sidx.
- if (I->start <= sidx) {
- sidx = I->end;
- // Move to the next run, remove iters when all are consumed.
- I = ++Iters[i].first;
- if (I == Iters[i].second) {
- Iters.erase(Iters.begin() + i);
- --i;
- continue;
- }
- }
- // Trim eidx too if needed.
- if (I->start >= eidx)
+ // Skip instructions that don't read Reg.
+ if (MO.isDef()) {
+ if (!MO.getSubReg() && !MO.isEarlyClobber())
continue;
- eidx = I->start;
- next = I->end;
- }
- // Now, [sidx;eidx) doesn't overlap anything in intervals_.
- if (sidx < eidx)
- dupli_.addSimpleRange(sidx, eidx, VNI);
- // If the interval end was truncated, we can try again from next.
- if (next <= sidx)
- break;
- sidx = next;
+ // We may wan't to extend a live range for a partial redef, or for a use
+ // tied to an early clobber.
+ Idx = Idx.getPrevSlot();
+ if (!Edit->getParent().liveAt(Idx))
+ continue;
+ } else
+ Idx = Idx.getUseIndex();
+
+ extendRange(RegIdx, Idx);
}
}
-void SplitEditor::computeRemainder() {
- // First we need to fill in the live ranges in dupli.
- // If values were redefined, we need a full recoloring with SSA update.
- // If values were truncated, we only need to truncate the ranges.
- // If values were partially rematted, we should shrink to uses.
- // If values were fully rematted, they should be omitted.
- // FIXME: If a single value is redefined, just move the def and truncate.
- LiveInterval &parent = edit_.getParent();
-
- // Values that are fully contained in the split intervals.
- SmallPtrSet<const VNInfo*, 8> deadValues;
- // Map all curli values that should have live defs in dupli.
- for (LiveInterval::const_vni_iterator I = parent.vni_begin(),
- E = parent.vni_end(); I != E; ++I) {
- const VNInfo *VNI = *I;
- // Don't transfer unused values to the new intervals.
- if (VNI->isUnused())
- continue;
- // Original def is contained in the split intervals.
- if (intervalsLiveAt(VNI->def)) {
- // Did this value escape?
- if (dupli_.isMapped(VNI))
- truncatedValues.insert(VNI);
- else
- deadValues.insert(VNI);
- continue;
- }
- // Add minimal live range at the definition.
- VNInfo *DVNI = dupli_.defValue(VNI, VNI->def);
- dupli_.getLI()->addRange(LiveRange(VNI->def, VNI->def.getNextSlot(), DVNI));
- }
+void SplitEditor::deleteRematVictims() {
+ SmallVector<MachineInstr*, 8> Dead;
+ for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I){
+ LiveInterval *LI = *I;
+ for (LiveInterval::const_iterator LII = LI->begin(), LIE = LI->end();
+ LII != LIE; ++LII) {
+ // Dead defs end at the store slot.
+ if (LII->end != LII->valno->def.getNextSlot())
+ continue;
+ MachineInstr *MI = LIS.getInstructionFromIndex(LII->valno->def);
+ assert(MI && "Missing instruction for dead def");
+ MI->addRegisterDead(LI->reg, &TRI);
+
+ if (!MI->allDefsAreDead())
+ continue;
- // Add all ranges to dupli.
- for (LiveInterval::const_iterator I = parent.begin(), E = parent.end();
- I != E; ++I) {
- const LiveRange &LR = *I;
- if (truncatedValues.count(LR.valno)) {
- // recolor after removing intervals_.
- addTruncSimpleRange(LR.start, LR.end, LR.valno);
- } else if (!deadValues.count(LR.valno)) {
- // recolor without truncation.
- dupli_.addSimpleRange(LR.start, LR.end, LR.valno);
+ DEBUG(dbgs() << "All defs dead: " << *MI);
+ Dead.push_back(MI);
}
}
- // Extend dupli_ to be live out of any critical loop predecessors.
- // This means we have multiple registers live out of those blocks.
- // The alternative would be to split the critical edges.
- if (criticalPreds_.empty())
+ if (Dead.empty())
return;
- for (SplitAnalysis::BlockPtrSet::iterator I = criticalPreds_.begin(),
- E = criticalPreds_.end(); I != E; ++I)
- dupli_.extendTo(*I, lis_.getMBBEndIdx(*I).getPrevSlot());
- criticalPreds_.clear();
+
+ Edit->eliminateDeadDefs(Dead, LIS, VRM, TII);
}
void SplitEditor::finish() {
- assert(!openli_.getLI() && "Previous LI not closed before rewrite");
- assert(dupli_.getLI() && "No dupli for rewrite. Noop spilt?");
+ assert(OpenIdx == 0 && "Previous LI not closed before rewrite");
+ ++NumFinished;
- // Complete dupli liveness.
- computeRemainder();
+ // At this point, the live intervals in Edit contain VNInfos corresponding to
+ // the inserted copies.
- // Get rid of unused values and set phi-kill flags.
- for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I)
- (*I)->RenumberValues(lis_);
+ // Add the original defs from the parent interval.
+ for (LiveInterval::const_vni_iterator I = Edit->getParent().vni_begin(),
+ E = Edit->getParent().vni_end(); I != E; ++I) {
+ const VNInfo *ParentVNI = *I;
+ if (ParentVNI->isUnused())
+ continue;
+ unsigned RegIdx = RegAssign.lookup(ParentVNI->def);
+ VNInfo *VNI = defValue(RegIdx, ParentVNI, ParentVNI->def);
+ VNI->setIsPHIDef(ParentVNI->isPHIDef());
+ VNI->setCopy(ParentVNI->getCopy());
+
+ // Mark rematted values as complex everywhere to force liveness computation.
+ // The new live ranges may be truncated.
+ if (Edit->didRematerialize(ParentVNI))
+ for (unsigned i = 0, e = Edit->size(); i != e; ++i)
+ markComplexMapped(i, ParentVNI);
+ }
+
+#ifndef NDEBUG
+ // Every new interval must have a def by now, otherwise the split is bogus.
+ for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I)
+ assert((*I)->hasAtLeastOneValue() && "Split interval has no value");
+#endif
+
+ // Transfer the simply mapped values, check if any are complex.
+ bool Complex = transferSimpleValues();
+ if (Complex)
+ extendPHIKillRanges();
+ else
+ ++NumSimple;
- // Rewrite instructions.
- rewrite(edit_.getReg());
+ // Rewrite virtual registers, possibly extending ranges.
+ rewriteAssigned(Complex);
+
+ // Delete defs that were rematted everywhere.
+ if (Complex)
+ deleteRematVictims();
+
+ // Get rid of unused values and set phi-kill flags.
+ for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I)
+ (*I)->RenumberValues(LIS);
// Now check if any registers were separated into multiple components.
- ConnectedVNInfoEqClasses ConEQ(lis_);
- for (unsigned i = 0, e = edit_.size(); i != e; ++i) {
+ ConnectedVNInfoEqClasses ConEQ(LIS);
+ for (unsigned i = 0, e = Edit->size(); i != e; ++i) {
// Don't use iterators, they are invalidated by create() below.
- LiveInterval *li = edit_.get(i);
+ LiveInterval *li = Edit->get(i);
unsigned NumComp = ConEQ.Classify(li);
if (NumComp <= 1)
continue;
SmallVector<LiveInterval*, 8> dups;
dups.push_back(li);
for (unsigned i = 1; i != NumComp; ++i)
- dups.push_back(&edit_.create(mri_, lis_, vrm_));
- ConEQ.Distribute(&dups[0]);
- // Rewrite uses to the new regs.
- rewrite(li->reg);
+ dups.push_back(&Edit->create(LIS, VRM));
+ ConEQ.Distribute(&dups[0], MRI);
}
// Calculate spill weight and allocation hints for new intervals.
- VirtRegAuxInfo vrai(vrm_.getMachineFunction(), lis_, sa_.loops_);
- for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I){
+ VirtRegAuxInfo vrai(VRM.getMachineFunction(), LIS, SA.Loops);
+ for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I){
LiveInterval &li = **I;
vrai.CalculateRegClass(li.reg);
vrai.CalculateWeightAndHint(li);
- DEBUG(dbgs() << " new interval " << mri_.getRegClass(li.reg)->getName()
+ DEBUG(dbgs() << " new interval " << MRI.getRegClass(li.reg)->getName()
<< ":" << li << '\n');
}
}
-//===----------------------------------------------------------------------===//
-// Loop Splitting
-//===----------------------------------------------------------------------===//
-
-void SplitEditor::splitAroundLoop(const MachineLoop *Loop) {
- SplitAnalysis::LoopBlocks Blocks;
- sa_.getLoopBlocks(Loop, Blocks);
-
- DEBUG({
- dbgs() << " splitAround"; sa_.print(Blocks, dbgs()); dbgs() << '\n';
- });
-
- // Break critical edges as needed.
- SplitAnalysis::BlockPtrSet CriticalExits;
- sa_.getCriticalExits(Blocks, CriticalExits);
- assert(CriticalExits.empty() && "Cannot break critical exits yet");
-
- // Get critical predecessors so computeRemainder can deal with them.
- sa_.getCriticalPreds(Blocks, criticalPreds_);
-
- // Create new live interval for the loop.
- openIntv();
-
- // Insert copies in the predecessors.
- for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Preds.begin(),
- E = Blocks.Preds.end(); I != E; ++I) {
- MachineBasicBlock &MBB = const_cast<MachineBasicBlock&>(**I);
- enterIntvAtEnd(MBB);
- }
-
- // Switch all loop blocks.
- for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Loop.begin(),
- E = Blocks.Loop.end(); I != E; ++I)
- useIntv(**I);
-
- // Insert back copies in the exit blocks.
- for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Exits.begin(),
- E = Blocks.Exits.end(); I != E; ++I) {
- MachineBasicBlock &MBB = const_cast<MachineBasicBlock&>(**I);
- leaveIntvAtTop(MBB);
- }
-
- // Done.
- closeIntv();
- finish();
-}
-
-
//===----------------------------------------------------------------------===//
// Single Block Splitting
//===----------------------------------------------------------------------===//
-/// getMultiUseBlocks - if curli has more than one use in a basic block, it
-/// may be an advantage to split curli for the duration of the block.
+/// getMultiUseBlocks - if CurLI has more than one use in a basic block, it
+/// may be an advantage to split CurLI for the duration of the block.
bool SplitAnalysis::getMultiUseBlocks(BlockPtrSet &Blocks) {
- // If curli is local to one block, there is no point to splitting it.
- if (usingBlocks_.size() <= 1)
+ // If CurLI is local to one block, there is no point to splitting it.
+ if (LiveBlocks.size() <= 1)
return false;
// Add blocks with multiple uses.
- for (BlockCountMap::iterator I = usingBlocks_.begin(), E = usingBlocks_.end();
- I != E; ++I)
- switch (I->second) {
- case 0:
- case 1:
+ for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
+ const BlockInfo &BI = LiveBlocks[i];
+ if (!BI.Uses)
continue;
- case 2: {
- // When there are only two uses and curli is both live in and live out,
- // we don't really win anything by isolating the block since we would be
- // inserting two copies.
- // The remaing register would still have two uses in the block. (Unless it
- // separates into disconnected components).
- if (lis_.isLiveInToMBB(*curli_, I->first) &&
- lis_.isLiveOutOfMBB(*curli_, I->first))
- continue;
- } // Fall through.
- default:
- Blocks.insert(I->first);
- }
+ unsigned Instrs = UsingBlocks.lookup(BI.MBB);
+ if (Instrs <= 1)
+ continue;
+ if (Instrs == 2 && BI.LiveIn && BI.LiveOut && !BI.LiveThrough)
+ continue;
+ Blocks.insert(BI.MBB);
+ }
return !Blocks.empty();
}
-/// splitSingleBlocks - Split curli into a separate live interval inside each
+/// splitSingleBlocks - Split CurLI into a separate live interval inside each
/// basic block in Blocks.
void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
DEBUG(dbgs() << " splitSingleBlocks for " << Blocks.size() << " blocks.\n");
- // Determine the first and last instruction using curli in each block.
- typedef std::pair<SlotIndex,SlotIndex> IndexPair;
- typedef DenseMap<const MachineBasicBlock*,IndexPair> IndexPairMap;
- IndexPairMap MBBRange;
- for (SplitAnalysis::InstrPtrSet::const_iterator I = sa_.usingInstrs_.begin(),
- E = sa_.usingInstrs_.end(); I != E; ++I) {
- const MachineBasicBlock *MBB = (*I)->getParent();
- if (!Blocks.count(MBB))
- continue;
- SlotIndex Idx = lis_.getInstructionIndex(*I);
- DEBUG(dbgs() << " BB#" << MBB->getNumber() << '\t' << Idx << '\t' << **I);
- IndexPair &IP = MBBRange[MBB];
- if (!IP.first.isValid() || Idx < IP.first)
- IP.first = Idx;
- if (!IP.second.isValid() || Idx > IP.second)
- IP.second = Idx;
- }
-
- // Create a new interval for each block.
- for (SplitAnalysis::BlockPtrSet::const_iterator I = Blocks.begin(),
- E = Blocks.end(); I != E; ++I) {
- IndexPair &IP = MBBRange[*I];
- DEBUG(dbgs() << " splitting for BB#" << (*I)->getNumber() << ": ["
- << IP.first << ';' << IP.second << ")\n");
- assert(IP.first.isValid() && IP.second.isValid());
-
- openIntv();
- enterIntvBefore(IP.first);
- useIntv(IP.first.getBaseIndex(), IP.second.getBoundaryIndex());
- leaveIntvAfter(IP.second);
- closeIntv();
- }
- finish();
-}
+ for (unsigned i = 0, e = SA.LiveBlocks.size(); i != e; ++i) {
+ const SplitAnalysis::BlockInfo &BI = SA.LiveBlocks[i];
+ if (!BI.Uses || !Blocks.count(BI.MBB))
+ continue;
-//===----------------------------------------------------------------------===//
-// Sub Block Splitting
-//===----------------------------------------------------------------------===//
-
-/// getBlockForInsideSplit - If curli is contained inside a single basic block,
-/// and it wou pay to subdivide the interval inside that block, return it.
-/// Otherwise return NULL. The returned block can be passed to
-/// SplitEditor::splitInsideBlock.
-const MachineBasicBlock *SplitAnalysis::getBlockForInsideSplit() {
- // The interval must be exclusive to one block.
- if (usingBlocks_.size() != 1)
- return 0;
- // Don't to this for less than 4 instructions. We want to be sure that
- // splitting actually reduces the instruction count per interval.
- if (usingInstrs_.size() < 4)
- return 0;
- return usingBlocks_.begin()->first;
-}
-
-/// splitInsideBlock - Split curli into multiple intervals inside MBB.
-void SplitEditor::splitInsideBlock(const MachineBasicBlock *MBB) {
- SmallVector<SlotIndex, 32> Uses;
- Uses.reserve(sa_.usingInstrs_.size());
- for (SplitAnalysis::InstrPtrSet::const_iterator I = sa_.usingInstrs_.begin(),
- E = sa_.usingInstrs_.end(); I != E; ++I)
- if ((*I)->getParent() == MBB)
- Uses.push_back(lis_.getInstructionIndex(*I));
- DEBUG(dbgs() << " splitInsideBlock BB#" << MBB->getNumber() << " for "
- << Uses.size() << " instructions.\n");
- assert(Uses.size() >= 3 && "Need at least 3 instructions");
- array_pod_sort(Uses.begin(), Uses.end());
-
- // Simple algorithm: Find the largest gap between uses as determined by slot
- // indices. Create new intervals for instructions before the gap and after the
- // gap.
- unsigned bestPos = 0;
- int bestGap = 0;
- DEBUG(dbgs() << " dist (" << Uses[0]);
- for (unsigned i = 1, e = Uses.size(); i != e; ++i) {
- int g = Uses[i-1].distance(Uses[i]);
- DEBUG(dbgs() << ") -" << g << "- (" << Uses[i]);
- if (g > bestGap)
- bestPos = i, bestGap = g;
- }
- DEBUG(dbgs() << "), best: -" << bestGap << "-\n");
-
- // bestPos points to the first use after the best gap.
- assert(bestPos > 0 && "Invalid gap");
-
- // FIXME: Don't create intervals for low densities.
-
- // First interval before the gap. Don't create single-instr intervals.
- if (bestPos > 1) {
- openIntv();
- enterIntvBefore(Uses.front());
- useIntv(Uses.front().getBaseIndex(), Uses[bestPos-1].getBoundaryIndex());
- leaveIntvAfter(Uses[bestPos-1]);
- closeIntv();
- }
-
- // Second interval after the gap.
- if (bestPos < Uses.size()-1) {
openIntv();
- enterIntvBefore(Uses[bestPos]);
- useIntv(Uses[bestPos].getBaseIndex(), Uses.back().getBoundaryIndex());
- leaveIntvAfter(Uses.back());
+ SlotIndex SegStart = enterIntvBefore(std::min(BI.FirstUse,
+ BI.LastSplitPoint));
+ if (!BI.LiveOut || BI.LastUse < BI.LastSplitPoint) {
+ useIntv(SegStart, leaveIntvAfter(BI.LastUse));
+ } else {
+ // The last use is after the last valid split point.
+ SlotIndex SegStop = leaveIntvBefore(BI.LastSplitPoint);
+ useIntv(SegStart, SegStop);
+ overlapIntv(SegStop, BI.LastUse);
+ }
closeIntv();
}
-
finish();
}
projects / oota-llvm.git / blobdiff