RS_New, ///< Never seen before.
RS_First, ///< First time in the queue.
RS_Second, ///< Second time in the queue.
- RS_Region, ///< Produced by region splitting.
- RS_Block, ///< Produced by per-block splitting.
+ RS_Global, ///< Produced by global splitting.
RS_Local, ///< Produced by local splitting.
RS_Spill ///< Produced by spilling.
};
/// Cached per-block interference maps
InterferenceCache IntfCache;
- /// All basic blocks where the current register is live.
+ /// All basic blocks where the current register has uses.
SmallVector<SpillPlacement::BlockConstraint, 8> SplitConstraints;
/// Global live range splitting candidate info.
struct GlobalSplitCandidate {
unsigned PhysReg;
BitVector LiveBundles;
+ SmallVector<unsigned, 8> ActiveBlocks;
+
+ void reset(unsigned Reg) {
+ PhysReg = Reg;
+ LiveBundles.clear();
+ ActiveBlocks.clear();
+ }
};
/// Candidate info for for each PhysReg in AllocationOrder.
void LRE_WillShrinkVirtReg(unsigned);
void LRE_DidCloneVirtReg(unsigned, unsigned);
- bool addSplitConstraints(unsigned, float&);
- float calcGlobalSplitCost(unsigned, const BitVector&);
- void splitAroundRegion(LiveInterval&, unsigned, const BitVector&,
+ bool addSplitConstraints(InterferenceCache::Cursor, float&);
+ void addThroughConstraints(InterferenceCache::Cursor, ArrayRef<unsigned>);
+ void growRegion(GlobalSplitCandidate &Cand, InterferenceCache::Cursor);
+ float calcGlobalSplitCost(GlobalSplitCandidate&, InterferenceCache::Cursor);
+ void splitAroundRegion(LiveInterval&, GlobalSplitCandidate&,
SmallVectorImpl<LiveInterval*>&);
void calcGapWeights(unsigned, SmallVectorImpl<float>&);
SlotIndex getPrevMappedIndex(const MachineInstr*);
void RAGreedy::releaseMemory() {
SpillerInstance.reset(0);
LRStage.clear();
+ GlobalCand.clear();
RegAllocBase::releaseMemory();
}
//===----------------------------------------------------------------------===//
/// canEvict - Return true if all interferences between VirtReg and PhysReg can
-/// be evicted. Set maxWeight to the maximal spill weight of an interference.
+/// be evicted.
+/// Return false if any interference is heavier than MaxWeight.
+/// On return, set MaxWeight to the maximal spill weight of an interference.
bool RAGreedy::canEvictInterference(LiveInterval &VirtReg, unsigned PhysReg,
float &MaxWeight) {
float Weight = 0;
for (const unsigned *AliasI = TRI->getOverlaps(PhysReg); *AliasI; ++AliasI) {
LiveIntervalUnion::Query &Q = query(VirtReg, *AliasI);
- // If there is 10 or more interferences, chances are one is smaller.
- if (Q.collectInterferingVRegs(10) >= 10)
+ // If there is 10 or more interferences, chances are one is heavier.
+ if (Q.collectInterferingVRegs(10, MaxWeight) >= 10)
return false;
- // Check if any interfering live range is heavier than VirtReg.
- for (unsigned i = 0, e = Q.interferingVRegs().size(); i != e; ++i) {
- LiveInterval *Intf = Q.interferingVRegs()[i];
+ // Check if any interfering live range is heavier than MaxWeight.
+ for (unsigned i = Q.interferingVRegs().size(); i; --i) {
+ LiveInterval *Intf = Q.interferingVRegs()[i - 1];
if (TargetRegisterInfo::isPhysicalRegister(Intf->reg))
return false;
- if (Intf->weight >= VirtReg.weight)
+ if (Intf->weight >= MaxWeight)
return false;
Weight = std::max(Weight, Intf->weight);
}
NamedRegionTimer T("Evict", TimerGroupName, TimePassesIsEnabled);
// Keep track of the lightest single interference seen so far.
- float BestWeight = 0;
+ float BestWeight = VirtReg.weight;
unsigned BestPhys = 0;
Order.rewind();
while (unsigned PhysReg = Order.next()) {
- float Weight = 0;
+ float Weight = BestWeight;
if (!canEvictInterference(VirtReg, PhysReg, Weight))
continue;
// This is an eviction candidate.
- DEBUG(dbgs() << "max " << PrintReg(PhysReg, TRI) << " interference = "
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << " interference = "
<< Weight << '\n');
if (BestPhys && Weight >= BestWeight)
continue;
/// interference pattern in Physreg and its aliases. Add the constraints to
/// SpillPlacement and return the static cost of this split in Cost, assuming
/// that all preferences in SplitConstraints are met.
-/// If it is evident that no bundles will be live, abort early and return false.
-bool RAGreedy::addSplitConstraints(unsigned PhysReg, float &Cost) {
- InterferenceCache::Cursor Intf(IntfCache, PhysReg);
+/// Return false if there are no bundles with positive bias.
+bool RAGreedy::addSplitConstraints(InterferenceCache::Cursor Intf,
+ float &Cost) {
ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
// Reset interference dependent info.
if (Ins)
StaticCost += Ins * SpillPlacer->getBlockFrequency(BC.Number);
}
+ Cost = StaticCost;
// Add constraints for use-blocks. Note that these are the only constraints
// that may add a positive bias, it is downhill from here.
SpillPlacer->addConstraints(SplitConstraints);
- if (SpillPlacer->getPositiveNodes() == 0)
- return false;
+ return SpillPlacer->scanActiveBundles();
+}
- Cost = StaticCost;
- // Now handle the live-through blocks without uses. These can only add
- // negative bias, so we can abort whenever there are no more positive nodes.
- // Compute constraints for a group of 8 blocks at a time.
+/// addThroughConstraints - Add constraints and links to SpillPlacer from the
+/// live-through blocks in Blocks.
+void RAGreedy::addThroughConstraints(InterferenceCache::Cursor Intf,
+ ArrayRef<unsigned> Blocks) {
const unsigned GroupSize = 8;
SpillPlacement::BlockConstraint BCS[GroupSize];
- unsigned B = 0;
+ unsigned TBS[GroupSize];
+ unsigned B = 0, T = 0;
- ArrayRef<unsigned> ThroughBlocks = SA->getThroughBlocks();
- for (unsigned i = 0; i != ThroughBlocks.size(); ++i) {
- unsigned Number = ThroughBlocks[i];
- assert(B < GroupSize && "Array overflow");
- BCS[B].Number = Number;
+ for (unsigned i = 0; i != Blocks.size(); ++i) {
+ unsigned Number = Blocks[i];
Intf.moveToBlock(Number);
- if (Intf.hasInterference()) {
- // Interference for the live-in value.
- if (Intf.first() <= Indexes->getMBBStartIdx(Number))
- BCS[B].Entry = SpillPlacement::MustSpill;
- else
- BCS[B].Entry = SpillPlacement::PrefSpill;
-
- // Interference for the live-out value.
- if (Intf.last() >= SA->getLastSplitPoint(Number))
- BCS[B].Exit = SpillPlacement::MustSpill;
- else
- BCS[B].Exit = SpillPlacement::PrefSpill;
- } else {
- // No interference, transparent block.
- BCS[B].Entry = BCS[B].Exit = SpillPlacement::DontCare;
+ if (!Intf.hasInterference()) {
+ assert(T < GroupSize && "Array overflow");
+ TBS[T] = Number;
+ if (++T == GroupSize) {
+ SpillPlacer->addLinks(ArrayRef<unsigned>(TBS, T));
+ T = 0;
+ }
+ continue;
}
+ assert(B < GroupSize && "Array overflow");
+ BCS[B].Number = Number;
+
+ // Interference for the live-in value.
+ if (Intf.first() <= Indexes->getMBBStartIdx(Number))
+ BCS[B].Entry = SpillPlacement::MustSpill;
+ else
+ BCS[B].Entry = SpillPlacement::PrefSpill;
+
+ // Interference for the live-out value.
+ if (Intf.last() >= SA->getLastSplitPoint(Number))
+ BCS[B].Exit = SpillPlacement::MustSpill;
+ else
+ BCS[B].Exit = SpillPlacement::PrefSpill;
+
if (++B == GroupSize) {
ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
SpillPlacer->addConstraints(Array);
B = 0;
- // Abort early when all hope is lost.
- if (SpillPlacer->getPositiveNodes() == 0)
- return false;
}
}
ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
SpillPlacer->addConstraints(Array);
- return SpillPlacer->getPositiveNodes() != 0;
+ SpillPlacer->addLinks(ArrayRef<unsigned>(TBS, T));
}
+void RAGreedy::growRegion(GlobalSplitCandidate &Cand,
+ InterferenceCache::Cursor Intf) {
+ // Keep track of through blocks that have not been added to SpillPlacer.
+ BitVector Todo = SA->getThroughBlocks();
+ SmallVectorImpl<unsigned> &ActiveBlocks = Cand.ActiveBlocks;
+ unsigned AddedTo = 0;
+#ifndef NDEBUG
+ unsigned Visited = 0;
+#endif
+
+ for (;;) {
+ ArrayRef<unsigned> NewBundles = SpillPlacer->getRecentPositive();
+ if (NewBundles.empty())
+ break;
+ // Find new through blocks in the periphery of PrefRegBundles.
+ for (int i = 0, e = NewBundles.size(); i != e; ++i) {
+ unsigned Bundle = NewBundles[i];
+ // Look at all blocks connected to Bundle in the full graph.
+ ArrayRef<unsigned> Blocks = Bundles->getBlocks(Bundle);
+ for (ArrayRef<unsigned>::iterator I = Blocks.begin(), E = Blocks.end();
+ I != E; ++I) {
+ unsigned Block = *I;
+ if (!Todo.test(Block))
+ continue;
+ Todo.reset(Block);
+ // This is a new through block. Add it to SpillPlacer later.
+ ActiveBlocks.push_back(Block);
+#ifndef NDEBUG
+ ++Visited;
+#endif
+ }
+ }
+ // Any new blocks to add?
+ if (ActiveBlocks.size() > AddedTo) {
+ ArrayRef<unsigned> Add(&ActiveBlocks[AddedTo],
+ ActiveBlocks.size() - AddedTo);
+ addThroughConstraints(Intf, Add);
+ AddedTo = ActiveBlocks.size();
+ }
+ // Perhaps iterating can enable more bundles?
+ SpillPlacer->iterate();
+ }
+ DEBUG(dbgs() << ", v=" << Visited);
+}
/// calcGlobalSplitCost - Return the global split cost of following the split
/// pattern in LiveBundles. This cost should be added to the local cost of the
/// interference pattern in SplitConstraints.
///
-float RAGreedy::calcGlobalSplitCost(unsigned PhysReg,
- const BitVector &LiveBundles) {
+float RAGreedy::calcGlobalSplitCost(GlobalSplitCandidate &Cand,
+ InterferenceCache::Cursor Intf) {
float GlobalCost = 0;
+ const BitVector &LiveBundles = Cand.LiveBundles;
ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
for (unsigned i = 0; i != UseBlocks.size(); ++i) {
const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
GlobalCost += Ins * SpillPlacer->getBlockFrequency(BC.Number);
}
- InterferenceCache::Cursor Intf(IntfCache, PhysReg);
- ArrayRef<unsigned> ThroughBlocks = SA->getThroughBlocks();
- SplitConstraints.resize(UseBlocks.size() + ThroughBlocks.size());
- for (unsigned i = 0; i != ThroughBlocks.size(); ++i) {
- unsigned Number = ThroughBlocks[i];
+ for (unsigned i = 0, e = Cand.ActiveBlocks.size(); i != e; ++i) {
+ unsigned Number = Cand.ActiveBlocks[i];
bool RegIn = LiveBundles[Bundles->getBundle(Number, 0)];
bool RegOut = LiveBundles[Bundles->getBundle(Number, 1)];
if (!RegIn && !RegOut)
/// avoiding interference. The 'stack' interval is the complement constructed by
/// SplitEditor. It will contain the rest.
///
-void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
- const BitVector &LiveBundles,
+void RAGreedy::splitAroundRegion(LiveInterval &VirtReg,
+ GlobalSplitCandidate &Cand,
SmallVectorImpl<LiveInterval*> &NewVRegs) {
+ const BitVector &LiveBundles = Cand.LiveBundles;
+
DEBUG({
- dbgs() << "Splitting around region for " << PrintReg(PhysReg, TRI)
+ dbgs() << "Splitting around region for " << PrintReg(Cand.PhysReg, TRI)
<< " with bundles";
for (int i = LiveBundles.find_first(); i>=0; i = LiveBundles.find_next(i))
dbgs() << " EB#" << i;
dbgs() << ".\n";
});
- InterferenceCache::Cursor Intf(IntfCache, PhysReg);
+ InterferenceCache::Cursor Intf(IntfCache, Cand.PhysReg);
LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
SE->reset(LREdit);
// Create the main cross-block interval.
- SE->openIntv();
+ const unsigned MainIntv = SE->openIntv();
// First add all defs that are live out of a block.
ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
bool RegIn = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
bool RegOut = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
+ // Create separate intervals for isolated blocks with multiple uses.
+ if (!RegIn && !RegOut && BI.FirstUse != BI.LastUse) {
+ DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " isolated.\n");
+ SE->splitSingleBlock(BI);
+ SE->selectIntv(MainIntv);
+ continue;
+ }
+
// Should the register be live out?
if (!BI.LiveOut || !RegOut)
continue;
}
// Handle live-through blocks.
- ArrayRef<unsigned> ThroughBlocks = SA->getThroughBlocks();
- for (unsigned i = 0; i != ThroughBlocks.size(); ++i) {
- unsigned Number = ThroughBlocks[i];
+ for (unsigned i = 0, e = Cand.ActiveBlocks.size(); i != e; ++i) {
+ unsigned Number = Cand.ActiveBlocks[i];
bool RegIn = LiveBundles[Bundles->getBundle(Number, 0)];
bool RegOut = LiveBundles[Bundles->getBundle(Number, 1)];
DEBUG(dbgs() << "Live through BB#" << Number << '\n');
unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
SmallVectorImpl<LiveInterval*> &NewVRegs) {
- BitVector LiveBundles, BestBundles;
float BestCost = 0;
- unsigned BestReg = 0;
+ const unsigned NoCand = ~0u;
+ unsigned BestCand = NoCand;
Order.rewind();
for (unsigned Cand = 0; unsigned PhysReg = Order.next(); ++Cand) {
if (GlobalCand.size() <= Cand)
GlobalCand.resize(Cand+1);
- GlobalCand[Cand].PhysReg = PhysReg;
+ GlobalCand[Cand].reset(PhysReg);
- SpillPlacer->prepare(LiveBundles);
+ SpillPlacer->prepare(GlobalCand[Cand].LiveBundles);
float Cost;
- if (!addSplitConstraints(PhysReg, Cost)) {
- DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tno positive bias\n");
+ InterferenceCache::Cursor Intf(IntfCache, PhysReg);
+ if (!addSplitConstraints(Intf, Cost)) {
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tno positive bundles\n");
continue;
}
- DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tbiased = "
- << SpillPlacer->getPositiveNodes() << ", static = " << Cost);
- if (BestReg && Cost >= BestCost) {
- DEBUG(dbgs() << " worse than " << PrintReg(BestReg, TRI) << '\n');
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tstatic = " << Cost);
+ if (BestCand != NoCand && Cost >= BestCost) {
+ DEBUG(dbgs() << " worse than "
+ << PrintReg(GlobalCand[BestCand].PhysReg, TRI) << '\n');
continue;
}
+ growRegion(GlobalCand[Cand], Intf);
SpillPlacer->finish();
// No live bundles, defer to splitSingleBlocks().
- if (!LiveBundles.any()) {
+ if (!GlobalCand[Cand].LiveBundles.any()) {
DEBUG(dbgs() << " no bundles.\n");
continue;
}
- Cost += calcGlobalSplitCost(PhysReg, LiveBundles);
+ Cost += calcGlobalSplitCost(GlobalCand[Cand], Intf);
DEBUG({
dbgs() << ", total = " << Cost << " with bundles";
- for (int i = LiveBundles.find_first(); i>=0; i = LiveBundles.find_next(i))
+ for (int i = GlobalCand[Cand].LiveBundles.find_first(); i>=0;
+ i = GlobalCand[Cand].LiveBundles.find_next(i))
dbgs() << " EB#" << i;
dbgs() << ".\n";
});
- if (!BestReg || Cost < BestCost) {
- BestReg = PhysReg;
+ if (BestCand == NoCand || Cost < BestCost) {
+ BestCand = Cand;
BestCost = 0.98f * Cost; // Prevent rounding effects.
- BestBundles.swap(LiveBundles);
}
}
- if (!BestReg)
+ if (BestCand == NoCand)
return 0;
- splitAroundRegion(VirtReg, BestReg, BestBundles, NewVRegs);
- setStage(NewVRegs.begin(), NewVRegs.end(), RS_Region);
+ splitAroundRegion(VirtReg, GlobalCand[BestCand], NewVRegs);
+ setStage(NewVRegs.begin(), NewVRegs.end(), RS_Global);
return 0;
}
// Don't iterate global splitting.
// Move straight to spilling if this range was produced by a global split.
- LiveRangeStage Stage = getStage(VirtReg);
- if (Stage >= RS_Block)
+ if (getStage(VirtReg) >= RS_Global)
return 0;
SA->analyze(&VirtReg);
// First try to split around a region spanning multiple blocks.
- if (Stage < RS_Region) {
- unsigned PhysReg = tryRegionSplit(VirtReg, Order, NewVRegs);
- if (PhysReg || !NewVRegs.empty())
- return PhysReg;
- }
+ unsigned PhysReg = tryRegionSplit(VirtReg, Order, NewVRegs);
+ if (PhysReg || !NewVRegs.empty())
+ return PhysReg;
// Then isolate blocks with multiple uses.
- if (Stage < RS_Block) {
- SplitAnalysis::BlockPtrSet Blocks;
- if (SA->getMultiUseBlocks(Blocks)) {
- LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
- SE->reset(LREdit);
- SE->splitSingleBlocks(Blocks);
- setStage(NewVRegs.begin(), NewVRegs.end(), RS_Block);
- if (VerifyEnabled)
- MF->verify(this, "After splitting live range around basic blocks");
- }
+ SplitAnalysis::BlockPtrSet Blocks;
+ if (SA->getMultiUseBlocks(Blocks)) {
+ LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
+ SE->reset(LREdit);
+ SE->splitSingleBlocks(Blocks);
+ setStage(NewVRegs.begin(), NewVRegs.end(), RS_Global);
+ if (VerifyEnabled)
+ MF->verify(this, "After splitting live range around basic blocks");
}
// Don't assign any physregs.
projects / oota-llvm.git / blobdiff