#include "SpillPlacement.h"
#include "SplitKit.h"
#include "VirtRegMap.h"
-#include "RegisterCoalescer.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/CodeGen/MachineLoopRanges.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/RegAllocRegistry.h"
#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
STATISTIC(NumLocalSplits, "Number of split local live ranges");
STATISTIC(NumEvicted, "Number of interferences evicted");
+static cl::opt<SplitEditor::ComplementSpillMode>
+SplitSpillMode("split-spill-mode", cl::Hidden,
+ cl::desc("Spill mode for splitting live ranges"),
+ cl::values(clEnumValN(SplitEditor::SM_Partition, "default", "Default"),
+ clEnumValN(SplitEditor::SM_Size, "size", "Optimize for size"),
+ clEnumValN(SplitEditor::SM_Speed, "speed", "Optimize for speed"),
+ clEnumValEnd),
+ cl::init(SplitEditor::SM_Partition));
+
static RegisterRegAlloc greedyRegAlloc("greedy", "greedy register allocator",
createGreedyRegisterAllocator);
LiveStacks *LS;
MachineDominatorTree *DomTree;
MachineLoopInfo *Loops;
- MachineLoopRanges *LoopRanges;
EdgeBundles *Bundles;
SpillPlacement *SpillPlacer;
LiveDebugVariables *DebugVars;
// range splitting algorithm terminates, something that is otherwise hard to
// ensure.
enum LiveRangeStage {
- RS_New, ///< Never seen before.
- RS_First, ///< First time in the queue.
- RS_Second, ///< Second time in the queue.
- RS_Global, ///< Produced by global splitting.
- RS_Local, ///< Produced by local splitting.
- RS_Spill ///< Produced by spilling.
+ /// Newly created live range that has never been queued.
+ RS_New,
+
+ /// Only attempt assignment and eviction. Then requeue as RS_Split.
+ RS_Assign,
+
+ /// Attempt live range splitting if assignment is impossible.
+ RS_Split,
+
+ /// Attempt more aggressive live range splitting that is guaranteed to make
+ /// progress. This is used for split products that may not be making
+ /// progress.
+ RS_Split2,
+
+ /// Live range will be spilled. No more splitting will be attempted.
+ RS_Spill,
+
+ /// There is nothing more we can do to this live range. Abort compilation
+ /// if it can't be assigned.
+ RS_Done
};
static const char *const StageName[];
}
};
+ // Register mask interference. The current VirtReg is checked for register
+ // mask interference on entry to selectOrSplit(). If there is no
+ // interference, UsableRegs is left empty. If there is interference,
+ // UsableRegs has a bit mask of registers that can be used without register
+ // mask interference.
+ BitVector UsableRegs;
+
+ /// clobberedByRegMask - Returns true if PhysReg is not directly usable
+ /// because of register mask clobbers.
+ bool clobberedByRegMask(unsigned PhysReg) const {
+ return !UsableRegs.empty() && !UsableRegs.test(PhysReg);
+ }
+
// splitting state.
std::auto_ptr<SplitAnalysis> SA;
std::auto_ptr<SplitEditor> SE;
/// Global live range splitting candidate info.
struct GlobalSplitCandidate {
+ // Register intended for assignment, or 0.
unsigned PhysReg;
+
+ // SplitKit interval index for this candidate.
+ unsigned IntvIdx;
+
+ // Interference for PhysReg.
InterferenceCache::Cursor Intf;
+
+ // Bundles where this candidate should be live.
BitVector LiveBundles;
SmallVector<unsigned, 8> ActiveBlocks;
void reset(InterferenceCache &Cache, unsigned Reg) {
PhysReg = Reg;
+ IntvIdx = 0;
Intf.setPhysReg(Cache, Reg);
LiveBundles.clear();
ActiveBlocks.clear();
}
+
+ // Set B[i] = C for every live bundle where B[i] was NoCand.
+ unsigned getBundles(SmallVectorImpl<unsigned> &B, unsigned C) {
+ unsigned Count = 0;
+ for (int i = LiveBundles.find_first(); i >= 0;
+ i = LiveBundles.find_next(i))
+ if (B[i] == NoCand) {
+ B[i] = C;
+ Count++;
+ }
+ return Count;
+ }
};
/// Candidate info for for each PhysReg in AllocationOrder.
/// class.
SmallVector<GlobalSplitCandidate, 32> GlobalCand;
+ enum { NoCand = ~0u };
+
+ /// Candidate map. Each edge bundle is assigned to a GlobalCand entry, or to
+ /// NoCand which indicates the stack interval.
+ SmallVector<unsigned, 32> BundleCand;
+
public:
RAGreedy();
static char ID;
private:
- void LRE_WillEraseInstruction(MachineInstr*);
bool LRE_CanEraseVirtReg(unsigned);
void LRE_WillShrinkVirtReg(unsigned);
void LRE_DidCloneVirtReg(unsigned, unsigned);
void addThroughConstraints(InterferenceCache::Cursor, ArrayRef<unsigned>);
void growRegion(GlobalSplitCandidate &Cand);
float calcGlobalSplitCost(GlobalSplitCandidate&);
- void splitAroundRegion(LiveInterval&, GlobalSplitCandidate&,
- SmallVectorImpl<LiveInterval*>&);
+ bool calcCompactRegion(GlobalSplitCandidate&);
+ void splitAroundRegion(LiveRangeEdit&, ArrayRef<unsigned>);
void calcGapWeights(unsigned, SmallVectorImpl<float>&);
bool shouldEvict(LiveInterval &A, bool, LiveInterval &B, bool);
bool canEvictInterference(LiveInterval&, unsigned, bool, EvictionCost&);
SmallVectorImpl<LiveInterval*>&, unsigned = ~0u);
unsigned tryRegionSplit(LiveInterval&, AllocationOrder&,
SmallVectorImpl<LiveInterval*>&);
+ unsigned tryBlockSplit(LiveInterval&, AllocationOrder&,
+ SmallVectorImpl<LiveInterval*>&);
unsigned tryLocalSplit(LiveInterval&, AllocationOrder&,
SmallVectorImpl<LiveInterval*>&);
unsigned trySplit(LiveInterval&, AllocationOrder&,
#ifndef NDEBUG
const char *const RAGreedy::StageName[] = {
- "RS_New",
- "RS_First",
- "RS_Second",
- "RS_Global",
- "RS_Local",
- "RS_Spill"
+ "RS_New",
+ "RS_Assign",
+ "RS_Split",
+ "RS_Split2",
+ "RS_Spill",
+ "RS_Done"
};
#endif
initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
- initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry());
initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry());
+ initializeMachineSchedulerPass(*PassRegistry::getPassRegistry());
initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
initializeLiveStacksPass(*PassRegistry::getPassRegistry());
initializeMachineDominatorTreePass(*PassRegistry::getPassRegistry());
initializeMachineLoopInfoPass(*PassRegistry::getPassRegistry());
- initializeMachineLoopRangesPass(*PassRegistry::getPassRegistry());
initializeVirtRegMapPass(*PassRegistry::getPassRegistry());
initializeEdgeBundlesPass(*PassRegistry::getPassRegistry());
initializeSpillPlacementPass(*PassRegistry::getPassRegistry());
AU.addPreserved<SlotIndexes>();
AU.addRequired<LiveDebugVariables>();
AU.addPreserved<LiveDebugVariables>();
- if (StrongPHIElim)
- AU.addRequiredID(StrongPHIEliminationID);
- AU.addRequiredTransitive<RegisterCoalescer>();
AU.addRequired<CalculateSpillWeights>();
AU.addRequired<LiveStacks>();
AU.addPreserved<LiveStacks>();
AU.addPreserved<MachineDominatorTree>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineLoopInfo>();
- AU.addRequired<MachineLoopRanges>();
- AU.addPreserved<MachineLoopRanges>();
AU.addRequired<VirtRegMap>();
AU.addPreserved<VirtRegMap>();
AU.addRequired<EdgeBundles>();
// LiveRangeEdit delegate methods
//===----------------------------------------------------------------------===//
-void RAGreedy::LRE_WillEraseInstruction(MachineInstr *MI) {
- // LRE itself will remove from SlotIndexes and parent basic block.
- VRM->RemoveMachineInstrFromMaps(MI);
-}
-
bool RAGreedy::LRE_CanEraseVirtReg(unsigned VirtReg) {
if (unsigned PhysReg = VRM->getPhys(VirtReg)) {
unassign(LIS->getInterval(VirtReg), PhysReg);
}
void RAGreedy::LRE_DidCloneVirtReg(unsigned New, unsigned Old) {
+ // Cloning a register we haven't even heard about yet? Just ignore it.
+ if (!ExtraRegInfo.inBounds(Old))
+ return;
+
// LRE may clone a virtual register because dead code elimination causes it to
- // be split into connected components. Ensure that the new register gets the
+ // be split into connected components. The new components are much smaller
+ // than the original, so they should get a new chance at being assigned.
// same stage as the parent.
+ ExtraRegInfo[Old].Stage = RS_Assign;
ExtraRegInfo.grow(New);
ExtraRegInfo[New] = ExtraRegInfo[Old];
}
ExtraRegInfo.grow(Reg);
if (ExtraRegInfo[Reg].Stage == RS_New)
- ExtraRegInfo[Reg].Stage = RS_First;
+ ExtraRegInfo[Reg].Stage = RS_Assign;
- if (ExtraRegInfo[Reg].Stage == RS_Second)
+ if (ExtraRegInfo[Reg].Stage == RS_Split) {
// Unsplit ranges that couldn't be allocated immediately are deferred until
- // everything else has been allocated. Long ranges are allocated last so
- // they are split against realistic interference.
- Prio = (1u << 31) - Size;
- else {
- // Everything else is allocated in long->short order. Long ranges that don't
- // fit should be spilled ASAP so they don't create interference.
+ // everything else has been allocated.
+ Prio = Size;
+ } else {
+ // Everything is allocated in long->short order. Long ranges that don't fit
+ // should be spilled (or split) ASAP so they don't create interference.
Prio = (1u << 31) + Size;
// Boost ranges that have a physical register hint.
SmallVectorImpl<LiveInterval*> &NewVRegs) {
Order.rewind();
unsigned PhysReg;
- while ((PhysReg = Order.next()))
+ while ((PhysReg = Order.next())) {
+ if (clobberedByRegMask(PhysReg))
+ continue;
if (!checkPhysRegInterference(VirtReg, PhysReg))
break;
+ }
if (!PhysReg || Order.isHint(PhysReg))
return PhysReg;
// If we missed a simple hint, try to cheaply evict interference from the
// preferred register.
if (unsigned Hint = MRI->getSimpleHint(VirtReg.reg))
- if (Order.isHint(Hint)) {
+ if (Order.isHint(Hint) && !clobberedByRegMask(Hint)) {
DEBUG(dbgs() << "missed hint " << PrintReg(Hint, TRI) << '\n');
EvictionCost MaxCost(1);
if (canEvictInterference(VirtReg, Hint, true, MaxCost)) {
/// @param BreaksHint True when B is already assigned to its preferred register.
bool RAGreedy::shouldEvict(LiveInterval &A, bool IsHint,
LiveInterval &B, bool BreaksHint) {
- bool CanSplit = getStage(B) <= RS_Second;
+ bool CanSplit = getStage(B) < RS_Spill;
// Be fairly aggressive about following hints as long as the evictee can be
// split.
if (TargetRegisterInfo::isPhysicalRegister(Intf->reg))
return false;
// Never evict spill products. They cannot split or spill.
- if (getStage(*Intf) == RS_Spill)
+ if (getStage(*Intf) == RS_Done)
return false;
// Once a live range becomes small enough, it is urgent that we find a
// register for it. This is indicated by an infinite spill weight. These
Order.rewind();
while (unsigned PhysReg = Order.next()) {
+ if (clobberedByRegMask(PhysReg))
+ continue;
if (TRI->getCostPerUse(PhysReg) >= CostPerUseLimit)
continue;
// The first use of a callee-saved register in a function has cost 1.
Intf.moveToBlock(BC.Number);
BC.Entry = BI.LiveIn ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
BC.Exit = BI.LiveOut ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
+ BC.ChangesValue = BI.FirstDef;
if (!Intf.hasInterference())
continue;
if (BI.LiveIn) {
if (Intf.first() <= Indexes->getMBBStartIdx(BC.Number))
BC.Entry = SpillPlacement::MustSpill, ++Ins;
- else if (Intf.first() < BI.FirstUse)
+ else if (Intf.first() < BI.FirstInstr)
BC.Entry = SpillPlacement::PrefSpill, ++Ins;
- else if (Intf.first() < BI.LastUse)
+ else if (Intf.first() < BI.LastInstr)
++Ins;
}
if (BI.LiveOut) {
if (Intf.last() >= SA->getLastSplitPoint(BC.Number))
BC.Exit = SpillPlacement::MustSpill, ++Ins;
- else if (Intf.last() > BI.LastUse)
+ else if (Intf.last() > BI.LastInstr)
BC.Exit = SpillPlacement::PrefSpill, ++Ins;
- else if (Intf.last() > BI.FirstUse)
+ else if (Intf.last() > BI.FirstInstr)
++Ins;
}
assert(T < GroupSize && "Array overflow");
TBS[T] = Number;
if (++T == GroupSize) {
- SpillPlacer->addLinks(ArrayRef<unsigned>(TBS, T));
+ SpillPlacer->addLinks(makeArrayRef(TBS, T));
T = 0;
}
continue;
ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
SpillPlacer->addConstraints(Array);
- SpillPlacer->addLinks(ArrayRef<unsigned>(TBS, T));
+ SpillPlacer->addLinks(makeArrayRef(TBS, T));
}
void RAGreedy::growRegion(GlobalSplitCandidate &Cand) {
// Any new blocks to add?
if (ActiveBlocks.size() == AddedTo)
break;
- addThroughConstraints(Cand.Intf,
- ArrayRef<unsigned>(ActiveBlocks).slice(AddedTo));
+
+ // Compute through constraints from the interference, or assume that all
+ // through blocks prefer spilling when forming compact regions.
+ ArrayRef<unsigned> NewBlocks = makeArrayRef(ActiveBlocks).slice(AddedTo);
+ if (Cand.PhysReg)
+ addThroughConstraints(Cand.Intf, NewBlocks);
+ else
+ // Provide a strong negative bias on through blocks to prevent unwanted
+ // liveness on loop backedges.
+ SpillPlacer->addPrefSpill(NewBlocks, /* Strong= */ true);
AddedTo = ActiveBlocks.size();
// Perhaps iterating can enable more bundles?
DEBUG(dbgs() << ", v=" << Visited);
}
+/// calcCompactRegion - Compute the set of edge bundles that should be live
+/// when splitting the current live range into compact regions. Compact
+/// regions can be computed without looking at interference. They are the
+/// regions formed by removing all the live-through blocks from the live range.
+///
+/// Returns false if the current live range is already compact, or if the
+/// compact regions would form single block regions anyway.
+bool RAGreedy::calcCompactRegion(GlobalSplitCandidate &Cand) {
+ // Without any through blocks, the live range is already compact.
+ if (!SA->getNumThroughBlocks())
+ return false;
+
+ // Compact regions don't correspond to any physreg.
+ Cand.reset(IntfCache, 0);
+
+ DEBUG(dbgs() << "Compact region bundles");
+
+ // Use the spill placer to determine the live bundles. GrowRegion pretends
+ // that all the through blocks have interference when PhysReg is unset.
+ SpillPlacer->prepare(Cand.LiveBundles);
+
+ // The static split cost will be zero since Cand.Intf reports no interference.
+ float Cost;
+ if (!addSplitConstraints(Cand.Intf, Cost)) {
+ DEBUG(dbgs() << ", none.\n");
+ return false;
+ }
+
+ growRegion(Cand);
+ SpillPlacer->finish();
+
+ if (!Cand.LiveBundles.any()) {
+ DEBUG(dbgs() << ", none.\n");
+ return false;
+ }
+
+ DEBUG({
+ for (int i = Cand.LiveBundles.find_first(); i>=0;
+ i = Cand.LiveBundles.find_next(i))
+ dbgs() << " EB#" << i;
+ dbgs() << ".\n";
+ });
+ return true;
+}
+
/// calcSpillCost - Compute how expensive it would be to split the live range in
/// SA around all use blocks instead of forming bundle regions.
float RAGreedy::calcSpillCost() {
float Cost = 0;
- const LiveInterval &LI = SA->getParent();
ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
for (unsigned i = 0; i != UseBlocks.size(); ++i) {
const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
Cost += SpillPlacer->getBlockFrequency(Number);
// Unless the value is redefined in the block.
- if (BI.LiveIn && BI.LiveOut) {
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(Number);
- LiveInterval::const_iterator I = LI.find(Start);
- assert(I != LI.end() && "Expected live-in value");
- // Is there a different live-out value? If so, we need an extra spill
- // instruction.
- if (I->end < Stop)
- Cost += SpillPlacer->getBlockFrequency(Number);
- }
+ if (BI.LiveIn && BI.LiveOut && BI.FirstDef)
+ Cost += SpillPlacer->getBlockFrequency(Number);
}
return Cost;
}
return GlobalCost;
}
-/// splitAroundRegion - Split VirtReg around the region determined by
-/// LiveBundles. Make an effort to avoid interference from PhysReg.
+/// splitAroundRegion - Split the current live range around the regions
+/// determined by BundleCand and GlobalCand.
///
-/// The 'register' interval is going to contain as many uses as possible while
-/// avoiding interference. The 'stack' interval is the complement constructed by
-/// SplitEditor. It will contain the rest.
+/// Before calling this function, GlobalCand and BundleCand must be initialized
+/// so each bundle is assigned to a valid candidate, or NoCand for the
+/// stack-bound bundles. The shared SA/SE SplitAnalysis and SplitEditor
+/// objects must be initialized for the current live range, and intervals
+/// created for the used candidates.
///
-void RAGreedy::splitAroundRegion(LiveInterval &VirtReg,
- GlobalSplitCandidate &Cand,
- SmallVectorImpl<LiveInterval*> &NewVRegs) {
- const BitVector &LiveBundles = Cand.LiveBundles;
-
- DEBUG({
- 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 = Cand.Intf;
- LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
- SE->reset(LREdit);
-
- // Create the main cross-block interval.
- const unsigned MainIntv = SE->openIntv();
+/// @param LREdit The LiveRangeEdit object handling the current split.
+/// @param UsedCands List of used GlobalCand entries. Every BundleCand value
+/// must appear in this list.
+void RAGreedy::splitAroundRegion(LiveRangeEdit &LREdit,
+ ArrayRef<unsigned> UsedCands) {
+ // These are the intervals created for new global ranges. We may create more
+ // intervals for local ranges.
+ const unsigned NumGlobalIntvs = LREdit.size();
+ DEBUG(dbgs() << "splitAroundRegion with " << NumGlobalIntvs << " globals.\n");
+ assert(NumGlobalIntvs && "No global intervals configured");
+
+ // Isolate even single instructions when dealing with a proper sub-class.
+ // That guarantees register class inflation for the stack interval because it
+ // is all copies.
+ unsigned Reg = SA->getParent().reg;
+ bool SingleInstrs = RegClassInfo.isProperSubClass(MRI->getRegClass(Reg));
// First handle all the blocks with uses.
ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
for (unsigned i = 0; i != UseBlocks.size(); ++i) {
const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
- bool RegIn = BI.LiveIn &&
- LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
- bool RegOut = BI.LiveOut &&
- LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
-
- // Create separate intervals for isolated blocks with multiple uses.
- //
- // |---o---o---| Enter and leave on the stack.
- // ____-----____ Create local interval for uses.
- //
- // | o---o---| Defined in block, leave on stack.
- // -----____ Create local interval for uses.
- //
- // |---o---x | Enter on stack, killed in block.
- // ____----- Create local interval for uses.
- //
- if (!RegIn && !RegOut) {
- DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " isolated.\n");
- if (!BI.isOneInstr()) {
- SE->splitSingleBlock(BI);
- SE->selectIntv(MainIntv);
+ unsigned Number = BI.MBB->getNumber();
+ unsigned IntvIn = 0, IntvOut = 0;
+ SlotIndex IntfIn, IntfOut;
+ if (BI.LiveIn) {
+ unsigned CandIn = BundleCand[Bundles->getBundle(Number, 0)];
+ if (CandIn != NoCand) {
+ GlobalSplitCandidate &Cand = GlobalCand[CandIn];
+ IntvIn = Cand.IntvIdx;
+ Cand.Intf.moveToBlock(Number);
+ IntfIn = Cand.Intf.first();
}
- continue;
}
-
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
- Intf.moveToBlock(BI.MBB->getNumber());
- DEBUG(dbgs() << "EB#" << Bundles->getBundle(BI.MBB->getNumber(), 0)
- << (BI.LiveIn ? (RegIn ? " => " : " -> ") : " ")
- << "BB#" << BI.MBB->getNumber()
- << (BI.LiveOut ? (RegOut ? " => " : " -> ") : " ")
- << " EB#" << Bundles->getBundle(BI.MBB->getNumber(), 1)
- << " [" << Start << ';'
- << SA->getLastSplitPoint(BI.MBB->getNumber()) << '-' << Stop
- << ") uses [" << BI.FirstUse << ';' << BI.LastUse
- << ") intf [" << Intf.first() << ';' << Intf.last() << ')');
-
- // The interference interval should either be invalid or overlap MBB.
- assert((!Intf.hasInterference() || Intf.first() < Stop)
- && "Bad interference");
- assert((!Intf.hasInterference() || Intf.last() > Start)
- && "Bad interference");
-
- // We are now ready to decide where to split in the current block. There
- // are many variables guiding the decision:
- //
- // - RegIn / RegOut: The global splitting algorithm's decisions for our
- // ingoing and outgoing bundles.
- //
- // - BI.BlockIn / BI.BlockOut: Is the live range live-in and/or live-out
- // from this block.
- //
- // - Intf.hasInterference(): Is there interference in this block.
- //
- // - Intf.first() / Inft.last(): The range of interference.
- //
- // The live range should be split such that MainIntv is live-in when RegIn
- // is set, and live-out when RegOut is set. MainIntv should never overlap
- // the interference, and the stack interval should never have more than one
- // use per block.
-
- // No splits can be inserted after LastSplitPoint, overlap instead.
- SlotIndex LastSplitPoint = Stop;
- if (BI.LiveOut)
- LastSplitPoint = SA->getLastSplitPoint(BI.MBB->getNumber());
-
- // At this point, we know that either RegIn or RegOut is set. We dealt with
- // the all-stack case above.
-
- // Blocks without interference are relatively easy.
- if (!Intf.hasInterference()) {
- DEBUG(dbgs() << ", no interference.\n");
- SE->selectIntv(MainIntv);
- // The easiest case has MainIntv live through.
- //
- // |---o---o---| Live-in, live-out.
- // ============= Use MainIntv everywhere.
- //
- SlotIndex From = Start, To = Stop;
-
- // Block entry. Reload before the first use if MainIntv is not live-in.
- //
- // |---o-- Enter on stack.
- // ____=== Reload before first use.
- //
- // | o-- Defined in block.
- // === Use MainIntv from def.
- //
- if (!RegIn)
- From = SE->enterIntvBefore(BI.FirstUse);
-
- // Block exit. Handle cases where MainIntv is not live-out.
- if (!BI.LiveOut)
- //
- // --x | Killed in block.
- // === Use MainIntv up to kill.
- //
- To = SE->leaveIntvAfter(BI.LastUse);
- else if (!RegOut) {
- //
- // --o---| Live-out on stack.
- // ===____ Use MainIntv up to last use, switch to stack.
- //
- // -----o| Live-out on stack, last use after last split point.
- // ====== Extend MainIntv to last use, overlapping.
- // \____ Copy to stack interval before last split point.
- //
- if (BI.LastUse < LastSplitPoint)
- To = SE->leaveIntvAfter(BI.LastUse);
- else {
- // The last use is after the last split point, it is probably an
- // indirect branch.
- To = SE->leaveIntvBefore(LastSplitPoint);
- // Run a double interval from the split to the last use. This makes
- // it possible to spill the complement without affecting the indirect
- // branch.
- SE->overlapIntv(To, BI.LastUse);
- }
+ if (BI.LiveOut) {
+ unsigned CandOut = BundleCand[Bundles->getBundle(Number, 1)];
+ if (CandOut != NoCand) {
+ GlobalSplitCandidate &Cand = GlobalCand[CandOut];
+ IntvOut = Cand.IntvIdx;
+ Cand.Intf.moveToBlock(Number);
+ IntfOut = Cand.Intf.last();
}
-
- // Paint in MainIntv liveness for this block.
- SE->useIntv(From, To);
- continue;
}
- // We are now looking at a block with interference, and we know that either
- // RegIn or RegOut is set.
- assert(Intf.hasInterference() && (RegIn || RegOut) && "Bad invariant");
-
- // If the live range is not live through the block, it is possible that the
- // interference doesn't even overlap. Deal with those cases first. Since
- // no copy instructions are required, we can tolerate interference starting
- // or ending at the same instruction that kills or defines our live range.
-
- // Live-in, killed before interference.
- //
- // ~~~ Interference after kill.
- // |---o---x | Killed in block.
- // ========= Use MainIntv everywhere.
- //
- if (RegIn && !BI.LiveOut && BI.LastUse <= Intf.first()) {
- DEBUG(dbgs() << ", live-in, killed before interference.\n");
- SE->selectIntv(MainIntv);
- SlotIndex To = SE->leaveIntvAfter(BI.LastUse);
- SE->useIntv(Start, To);
- continue;
- }
-
- // Live-out, defined after interference.
- //
- // ~~~ Interference before def.
- // | o---o---| Defined in block.
- // ========= Use MainIntv everywhere.
- //
- if (RegOut && !BI.LiveIn && BI.FirstUse >= Intf.last()) {
- DEBUG(dbgs() << ", live-out, defined after interference.\n");
- SE->selectIntv(MainIntv);
- SlotIndex From = SE->enterIntvBefore(BI.FirstUse);
- SE->useIntv(From, Stop);
+ // Create separate intervals for isolated blocks with multiple uses.
+ if (!IntvIn && !IntvOut) {
+ DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " isolated.\n");
+ if (SA->shouldSplitSingleBlock(BI, SingleInstrs))
+ SE->splitSingleBlock(BI);
continue;
}
- // The interference is now known to overlap the live range, but it may
- // still be easy to avoid if all the interference is on one side of the
- // uses, and we enter or leave on the stack.
+ if (IntvIn && IntvOut)
+ SE->splitLiveThroughBlock(Number, IntvIn, IntfIn, IntvOut, IntfOut);
+ else if (IntvIn)
+ SE->splitRegInBlock(BI, IntvIn, IntfIn);
+ else
+ SE->splitRegOutBlock(BI, IntvOut, IntfOut);
+ }
- // Live-out on stack, interference after last use.
- //
- // ~~~ Interference after last use.
- // |---o---o---| Live-out on stack.
- // =========____ Leave MainIntv after last use.
- //
- // ~ Interference after last use.
- // |---o---o--o| Live-out on stack, late last use.
- // ============ Copy to stack after LSP, overlap MainIntv.
- // \_____ Stack interval is live-out.
- //
- if (!RegOut && Intf.first() > BI.LastUse.getBoundaryIndex()) {
- assert(RegIn && "Stack-in, stack-out should already be handled");
- if (BI.LastUse < LastSplitPoint) {
- DEBUG(dbgs() << ", live-in, stack-out, interference after last use.\n");
- SE->selectIntv(MainIntv);
- SlotIndex To = SE->leaveIntvAfter(BI.LastUse);
- assert(To <= Intf.first() && "Expected to avoid interference");
- SE->useIntv(Start, To);
- } else {
- DEBUG(dbgs() << ", live-in, stack-out, avoid last split point\n");
- SE->selectIntv(MainIntv);
- SlotIndex To = SE->leaveIntvBefore(LastSplitPoint);
- assert(To <= Intf.first() && "Expected to avoid interference");
- SE->overlapIntv(To, BI.LastUse);
- SE->useIntv(Start, To);
- }
- continue;
- }
+ // Handle live-through blocks. The relevant live-through blocks are stored in
+ // the ActiveBlocks list with each candidate. We need to filter out
+ // duplicates.
+ BitVector Todo = SA->getThroughBlocks();
+ for (unsigned c = 0; c != UsedCands.size(); ++c) {
+ ArrayRef<unsigned> Blocks = GlobalCand[UsedCands[c]].ActiveBlocks;
+ for (unsigned i = 0, e = Blocks.size(); i != e; ++i) {
+ unsigned Number = Blocks[i];
+ if (!Todo.test(Number))
+ continue;
+ Todo.reset(Number);
- // Live-in on stack, interference before first use.
- //
- // ~~~ Interference before first use.
- // |---o---o---| Live-in on stack.
- // ____========= Enter MainIntv before first use.
- //
- if (!RegIn && Intf.last() < BI.FirstUse.getBaseIndex()) {
- assert(RegOut && "Stack-in, stack-out should already be handled");
- DEBUG(dbgs() << ", stack-in, interference before first use.\n");
- SE->selectIntv(MainIntv);
- SlotIndex From = SE->enterIntvBefore(BI.FirstUse);
- assert(From >= Intf.last() && "Expected to avoid interference");
- SE->useIntv(From, Stop);
- continue;
- }
+ unsigned IntvIn = 0, IntvOut = 0;
+ SlotIndex IntfIn, IntfOut;
- // The interference is overlapping somewhere we wanted to use MainIntv. That
- // means we need to create a local interval that can be allocated a
- // different register.
- unsigned LocalIntv = SE->openIntv();
- DEBUG(dbgs() << ", creating local interval " << LocalIntv << ".\n");
-
- // We may be creating copies directly between MainIntv and LocalIntv,
- // bypassing the stack interval. When we do that, we should never use the
- // leaveIntv* methods as they define values in the stack interval. By
- // starting from the end of the block and working our way backwards, we can
- // get by with only enterIntv* methods.
- //
- // When selecting split points, we generally try to maximize the stack
- // interval as long at it contains no uses, maximize the main interval as
- // long as it doesn't overlap interference, and minimize the local interval
- // that we don't know how to allocate yet.
-
- // Handle the block exit, set Pos to the first handled slot.
- SlotIndex Pos = BI.LastUse;
- if (RegOut) {
- assert(Intf.last() < LastSplitPoint && "Cannot be live-out in register");
- // Create a snippet of MainIntv that is live-out.
- //
- // ~~~ Interference overlapping uses.
- // --o---| Live-out in MainIntv.
- // ----=== Switch from LocalIntv to MainIntv after interference.
- //
- SE->selectIntv(MainIntv);
- Pos = SE->enterIntvAfter(Intf.last());
- assert(Pos >= Intf.last() && "Expected to avoid interference");
- SE->useIntv(Pos, Stop);
- SE->selectIntv(LocalIntv);
- } else if (BI.LiveOut) {
- if (BI.LastUse < LastSplitPoint) {
- // Live-out on the stack.
- //
- // ~~~ Interference overlapping uses.
- // --o---| Live-out on stack.
- // ---____ Switch from LocalIntv to stack after last use.
- //
- Pos = SE->leaveIntvAfter(BI.LastUse);
- } else {
- // Live-out on the stack, last use after last split point.
- //
- // ~~~ Interference overlapping uses.
- // --o--o| Live-out on stack, late use.
- // ------ Copy to stack before LSP, overlap LocalIntv.
- // \__
- //
- Pos = SE->leaveIntvBefore(LastSplitPoint);
- // We need to overlap LocalIntv so it can reach LastUse.
- SE->overlapIntv(Pos, BI.LastUse);
+ unsigned CandIn = BundleCand[Bundles->getBundle(Number, 0)];
+ if (CandIn != NoCand) {
+ GlobalSplitCandidate &Cand = GlobalCand[CandIn];
+ IntvIn = Cand.IntvIdx;
+ Cand.Intf.moveToBlock(Number);
+ IntfIn = Cand.Intf.first();
}
- }
- // When not live-out, leave Pos at LastUse. We have handled everything from
- // Pos to Stop. Find the starting point for LocalIntv.
- assert(SE->currentIntv() == LocalIntv && "Expecting local interval");
-
- if (RegIn) {
- assert(Start < Intf.first() && "Cannot be live-in with interference");
- // Live-in in MainIntv, only use LocalIntv for interference.
- //
- // ~~~ Interference overlapping uses.
- // |---o-- Live-in in MainIntv.
- // ====--- Switch to LocalIntv before interference.
- //
- SlotIndex Switch = SE->enterIntvBefore(std::min(Pos, Intf.first()));
- assert(Switch <= Intf.first() && "Expected to avoid interference");
- SE->useIntv(Switch, Pos);
- SE->selectIntv(MainIntv);
- SE->useIntv(Start, Switch);
- } else {
- // Live-in on stack, enter LocalIntv before first use.
- //
- // ~~~ Interference overlapping uses.
- // |---o-- Live-in in MainIntv.
- // ____--- Reload to LocalIntv before interference.
- //
- // Defined in block.
- //
- // ~~~ Interference overlapping uses.
- // | o-- Defined in block.
- // --- Begin LocalIntv at first use.
- //
- SlotIndex Switch = SE->enterIntvBefore(std::min(Pos, BI.FirstUse));
- SE->useIntv(Switch, Pos);
- }
- }
-
- // Handle live-through blocks.
- SE->selectIntv(MainIntv);
- 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');
- if (RegIn && RegOut) {
- Intf.moveToBlock(Number);
- if (!Intf.hasInterference()) {
- SE->useIntv(Indexes->getMBBStartIdx(Number),
- Indexes->getMBBEndIdx(Number));
- continue;
+ unsigned CandOut = BundleCand[Bundles->getBundle(Number, 1)];
+ if (CandOut != NoCand) {
+ GlobalSplitCandidate &Cand = GlobalCand[CandOut];
+ IntvOut = Cand.IntvIdx;
+ Cand.Intf.moveToBlock(Number);
+ IntfOut = Cand.Intf.last();
}
+ if (!IntvIn && !IntvOut)
+ continue;
+ SE->splitLiveThroughBlock(Number, IntvIn, IntfIn, IntvOut, IntfOut);
}
- MachineBasicBlock *MBB = MF->getBlockNumbered(Number);
- if (RegIn)
- SE->leaveIntvAtTop(*MBB);
- if (RegOut)
- SE->enterIntvAtEnd(*MBB);
}
++NumGlobalSplits;
SmallVector<unsigned, 8> IntvMap;
SE->finish(&IntvMap);
- DebugVars->splitRegister(VirtReg.reg, LREdit.regs());
+ DebugVars->splitRegister(Reg, LREdit.regs());
ExtraRegInfo.resize(MRI->getNumVirtRegs());
unsigned OrigBlocks = SA->getNumLiveBlocks();
// Remainder interval. Don't try splitting again, spill if it doesn't
// allocate.
if (IntvMap[i] == 0) {
- setStage(Reg, RS_Global);
+ setStage(Reg, RS_Spill);
continue;
}
- // Main interval. Allow repeated splitting as long as the number of live
+ // Global intervals. Allow repeated splitting as long as the number of live
// blocks is strictly decreasing.
- if (IntvMap[i] == MainIntv) {
+ if (IntvMap[i] < NumGlobalIntvs) {
if (SA->countLiveBlocks(&Reg) >= OrigBlocks) {
DEBUG(dbgs() << "Main interval covers the same " << OrigBlocks
<< " blocks as original.\n");
// Don't allow repeated splitting as a safe guard against looping.
- setStage(Reg, RS_Global);
+ setStage(Reg, RS_Split2);
}
continue;
}
unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
SmallVectorImpl<LiveInterval*> &NewVRegs) {
- float BestCost = Hysteresis * calcSpillCost();
- DEBUG(dbgs() << "Cost of isolating all blocks = " << BestCost << '\n');
- const unsigned NoCand = ~0u;
+ unsigned NumCands = 0;
unsigned BestCand = NoCand;
+ float BestCost;
+ SmallVector<unsigned, 8> UsedCands;
+
+ // Check if we can split this live range around a compact region.
+ bool HasCompact = calcCompactRegion(GlobalCand.front());
+ if (HasCompact) {
+ // Yes, keep GlobalCand[0] as the compact region candidate.
+ NumCands = 1;
+ BestCost = HUGE_VALF;
+ } else {
+ // No benefit from the compact region, our fallback will be per-block
+ // splitting. Make sure we find a solution that is cheaper than spilling.
+ BestCost = Hysteresis * calcSpillCost();
+ DEBUG(dbgs() << "Cost of isolating all blocks = " << BestCost << '\n');
+ }
Order.rewind();
- for (unsigned Cand = 0; unsigned PhysReg = Order.next(); ++Cand) {
- if (GlobalCand.size() <= Cand)
- GlobalCand.resize(Cand+1);
- GlobalCand[Cand].reset(IntfCache, PhysReg);
+ while (unsigned PhysReg = Order.next()) {
+ // Discard bad candidates before we run out of interference cache cursors.
+ // This will only affect register classes with a lot of registers (>32).
+ if (NumCands == IntfCache.getMaxCursors()) {
+ unsigned WorstCount = ~0u;
+ unsigned Worst = 0;
+ for (unsigned i = 0; i != NumCands; ++i) {
+ if (i == BestCand || !GlobalCand[i].PhysReg)
+ continue;
+ unsigned Count = GlobalCand[i].LiveBundles.count();
+ if (Count < WorstCount)
+ Worst = i, WorstCount = Count;
+ }
+ --NumCands;
+ GlobalCand[Worst] = GlobalCand[NumCands];
+ if (BestCand == NumCands)
+ BestCand = Worst;
+ }
+
+ if (GlobalCand.size() <= NumCands)
+ GlobalCand.resize(NumCands+1);
+ GlobalSplitCandidate &Cand = GlobalCand[NumCands];
+ Cand.reset(IntfCache, PhysReg);
- SpillPlacer->prepare(GlobalCand[Cand].LiveBundles);
+ SpillPlacer->prepare(Cand.LiveBundles);
float Cost;
- if (!addSplitConstraints(GlobalCand[Cand].Intf, Cost)) {
+ if (!addSplitConstraints(Cand.Intf, Cost)) {
DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tno positive bundles\n");
continue;
}
});
continue;
}
- growRegion(GlobalCand[Cand]);
+ growRegion(Cand);
SpillPlacer->finish();
// No live bundles, defer to splitSingleBlocks().
- if (!GlobalCand[Cand].LiveBundles.any()) {
+ if (!Cand.LiveBundles.any()) {
DEBUG(dbgs() << " no bundles.\n");
continue;
}
- Cost += calcGlobalSplitCost(GlobalCand[Cand]);
+ Cost += calcGlobalSplitCost(Cand);
DEBUG({
dbgs() << ", total = " << Cost << " with bundles";
- for (int i = GlobalCand[Cand].LiveBundles.find_first(); i>=0;
- i = GlobalCand[Cand].LiveBundles.find_next(i))
+ for (int i = Cand.LiveBundles.find_first(); i>=0;
+ i = Cand.LiveBundles.find_next(i))
dbgs() << " EB#" << i;
dbgs() << ".\n";
});
if (Cost < BestCost) {
- BestCand = Cand;
+ BestCand = NumCands;
BestCost = Hysteresis * Cost; // Prevent rounding effects.
}
+ ++NumCands;
}
- if (BestCand == NoCand)
+ // No solutions found, fall back to single block splitting.
+ if (!HasCompact && BestCand == NoCand)
return 0;
- splitAroundRegion(VirtReg, GlobalCand[BestCand], NewVRegs);
+ // Prepare split editor.
+ LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
+ SE->reset(LREdit, SplitSpillMode);
+
+ // Assign all edge bundles to the preferred candidate, or NoCand.
+ BundleCand.assign(Bundles->getNumBundles(), NoCand);
+
+ // Assign bundles for the best candidate region.
+ if (BestCand != NoCand) {
+ GlobalSplitCandidate &Cand = GlobalCand[BestCand];
+ if (unsigned B = Cand.getBundles(BundleCand, BestCand)) {
+ UsedCands.push_back(BestCand);
+ Cand.IntvIdx = SE->openIntv();
+ DEBUG(dbgs() << "Split for " << PrintReg(Cand.PhysReg, TRI) << " in "
+ << B << " bundles, intv " << Cand.IntvIdx << ".\n");
+ (void)B;
+ }
+ }
+
+ // Assign bundles for the compact region.
+ if (HasCompact) {
+ GlobalSplitCandidate &Cand = GlobalCand.front();
+ assert(!Cand.PhysReg && "Compact region has no physreg");
+ if (unsigned B = Cand.getBundles(BundleCand, 0)) {
+ UsedCands.push_back(0);
+ Cand.IntvIdx = SE->openIntv();
+ DEBUG(dbgs() << "Split for compact region in " << B << " bundles, intv "
+ << Cand.IntvIdx << ".\n");
+ (void)B;
+ }
+ }
+
+ splitAroundRegion(LREdit, UsedCands);
return 0;
}
+//===----------------------------------------------------------------------===//
+// Per-Block Splitting
+//===----------------------------------------------------------------------===//
+
+/// tryBlockSplit - Split a global live range around every block with uses. This
+/// creates a lot of local live ranges, that will be split by tryLocalSplit if
+/// they don't allocate.
+unsigned RAGreedy::tryBlockSplit(LiveInterval &VirtReg, AllocationOrder &Order,
+ SmallVectorImpl<LiveInterval*> &NewVRegs) {
+ assert(&SA->getParent() == &VirtReg && "Live range wasn't analyzed");
+ unsigned Reg = VirtReg.reg;
+ bool SingleInstrs = RegClassInfo.isProperSubClass(MRI->getRegClass(Reg));
+ LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
+ SE->reset(LREdit, SplitSpillMode);
+ ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
+ for (unsigned i = 0; i != UseBlocks.size(); ++i) {
+ const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
+ if (SA->shouldSplitSingleBlock(BI, SingleInstrs))
+ SE->splitSingleBlock(BI);
+ }
+ // No blocks were split.
+ if (LREdit.empty())
+ return 0;
+
+ // We did split for some blocks.
+ SmallVector<unsigned, 8> IntvMap;
+ SE->finish(&IntvMap);
+
+ // Tell LiveDebugVariables about the new ranges.
+ DebugVars->splitRegister(Reg, LREdit.regs());
+
+ ExtraRegInfo.resize(MRI->getNumVirtRegs());
+
+ // Sort out the new intervals created by splitting. The remainder interval
+ // goes straight to spilling, the new local ranges get to stay RS_New.
+ for (unsigned i = 0, e = LREdit.size(); i != e; ++i) {
+ LiveInterval &LI = *LREdit.get(i);
+ if (getStage(LI) == RS_New && IntvMap[i] == 0)
+ setStage(LI, RS_Spill);
+ }
+
+ if (VerifyEnabled)
+ MF->verify(this, "After splitting live range around basic blocks");
+ return 0;
+}
+
//===----------------------------------------------------------------------===//
// Local Splitting
//===----------------------------------------------------------------------===//
SmallVectorImpl<float> &GapWeight) {
assert(SA->getUseBlocks().size() == 1 && "Not a local interval");
const SplitAnalysis::BlockInfo &BI = SA->getUseBlocks().front();
- const SmallVectorImpl<SlotIndex> &Uses = SA->UseSlots;
+ ArrayRef<SlotIndex> Uses = SA->getUseSlots();
const unsigned NumGaps = Uses.size()-1;
// Start and end points for the interference check.
- SlotIndex StartIdx = BI.LiveIn ? BI.FirstUse.getBaseIndex() : BI.FirstUse;
- SlotIndex StopIdx = BI.LiveOut ? BI.LastUse.getBoundaryIndex() : BI.LastUse;
+ SlotIndex StartIdx =
+ BI.LiveIn ? BI.FirstInstr.getBaseIndex() : BI.FirstInstr;
+ SlotIndex StopIdx =
+ BI.LiveOut ? BI.LastInstr.getBoundaryIndex() : BI.LastInstr;
GapWeight.assign(NumGaps, 0.0f);
.checkInterference())
continue;
- // We know that VirtReg is a continuous interval from FirstUse to LastUse,
- // so we don't need InterferenceQuery.
+ // We know that VirtReg is a continuous interval from FirstInstr to
+ // LastInstr, so we don't need InterferenceQuery.
//
// Interference that overlaps an instruction is counted in both gaps
// surrounding the instruction. The exception is interference before
// StartIdx and after StopIdx.
//
- LiveIntervalUnion::SegmentIter IntI = PhysReg2LiveUnion[*AI].find(StartIdx);
+ LiveIntervalUnion::SegmentIter IntI = getLiveUnion(*AI).find(StartIdx);
for (unsigned Gap = 0; IntI.valid() && IntI.start() < StopIdx; ++IntI) {
// Skip the gaps before IntI.
while (Uses[Gap+1].getBoundaryIndex() < IntI.start())
// while only covering a single block - A phi-def can use undef values from
// predecessors, and the block could be a single-block loop.
// We don't bother doing anything clever about such a case, we simply assume
- // that the interval is continuous from FirstUse to LastUse. We should make
- // sure that we don't do anything illegal to such an interval, though.
+ // that the interval is continuous from FirstInstr to LastInstr. We should
+ // make sure that we don't do anything illegal to such an interval, though.
- const SmallVectorImpl<SlotIndex> &Uses = SA->UseSlots;
+ ArrayRef<SlotIndex> Uses = SA->getUseSlots();
if (Uses.size() <= 2)
return 0;
const unsigned NumGaps = Uses.size()-1;
DEBUG({
dbgs() << "tryLocalSplit: ";
for (unsigned i = 0, e = Uses.size(); i != e; ++i)
- dbgs() << ' ' << SA->UseSlots[i];
+ dbgs() << ' ' << Uses[i];
dbgs() << '\n';
});
//
// Instead we use these rules:
//
- // 1. Allow any split for ranges with getStage() < RS_Local. (Except for the
+ // 1. Allow any split for ranges with getStage() < RS_Split2. (Except for the
// noop split, of course).
- // 2. Require progress be made for ranges with getStage() >= RS_Local. All
+ // 2. Require progress be made for ranges with getStage() == RS_Split2. All
// the new ranges must have fewer instructions than before the split.
- // 3. New ranges with the same number of instructions are marked RS_Local,
+ // 3. New ranges with the same number of instructions are marked RS_Split2,
// smaller ranges are marked RS_New.
//
// These rules allow a 3 -> 2+3 split once, which we need. They also prevent
// excessive splitting and infinite loops.
//
- bool ProgressRequired = getStage(VirtReg) >= RS_Local;
+ bool ProgressRequired = getStage(VirtReg) >= RS_Split2;
// Best split candidate.
unsigned BestBefore = NumGaps;
DebugVars->splitRegister(VirtReg.reg, LREdit.regs());
// If the new range has the same number of instructions as before, mark it as
- // RS_Local so the next split will be forced to make progress. Otherwise,
+ // RS_Split2 so the next split will be forced to make progress. Otherwise,
// leave the new intervals as RS_New so they can compete.
bool LiveBefore = BestBefore != 0 || BI.LiveIn;
bool LiveAfter = BestAfter != NumGaps || BI.LiveOut;
assert(!ProgressRequired && "Didn't make progress when it was required.");
for (unsigned i = 0, e = IntvMap.size(); i != e; ++i)
if (IntvMap[i] == 1) {
- setStage(*LREdit.get(i), RS_Local);
+ setStage(*LREdit.get(i), RS_Split2);
DEBUG(dbgs() << PrintReg(LREdit.get(i)->reg));
}
DEBUG(dbgs() << '\n');
/// @return Physreg when VirtReg may be assigned and/or new NewVRegs.
unsigned RAGreedy::trySplit(LiveInterval &VirtReg, AllocationOrder &Order,
SmallVectorImpl<LiveInterval*>&NewVRegs) {
+ // Ranges must be Split2 or less.
+ if (getStage(VirtReg) >= RS_Spill)
+ return 0;
+
// Local intervals are handled separately.
if (LIS->intervalIsInOneMBB(VirtReg)) {
NamedRegionTimer T("Local Splitting", TimerGroupName, TimePassesIsEnabled);
NamedRegionTimer T("Global Splitting", TimerGroupName, TimePassesIsEnabled);
- // Don't iterate global splitting.
- // Move straight to spilling if this range was produced by a global split.
- if (getStage(VirtReg) >= RS_Global)
- return 0;
-
SA->analyze(&VirtReg);
// FIXME: SplitAnalysis may repair broken live ranges coming from the
return PhysReg;
}
- // First try to split around a region spanning multiple blocks.
- unsigned PhysReg = tryRegionSplit(VirtReg, Order, NewVRegs);
- if (PhysReg || !NewVRegs.empty())
- return PhysReg;
-
- // Then isolate blocks with multiple uses.
- 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");
+ // First try to split around a region spanning multiple blocks. RS_Split2
+ // ranges already made dubious progress with region splitting, so they go
+ // straight to single block splitting.
+ if (getStage(VirtReg) < RS_Split2) {
+ unsigned PhysReg = tryRegionSplit(VirtReg, Order, NewVRegs);
+ if (PhysReg || !NewVRegs.empty())
+ return PhysReg;
}
- // Don't assign any physregs.
- return 0;
+ // Then isolate blocks.
+ return tryBlockSplit(VirtReg, Order, NewVRegs);
}
unsigned RAGreedy::selectOrSplit(LiveInterval &VirtReg,
SmallVectorImpl<LiveInterval*> &NewVRegs) {
+ // Check if VirtReg is live across any calls.
+ UsableRegs.clear();
+ if (LIS->checkRegMaskInterference(VirtReg, UsableRegs))
+ DEBUG(dbgs() << "Live across regmasks.\n");
+
// First try assigning a free register.
AllocationOrder Order(VirtReg.reg, *VRM, RegClassInfo);
if (unsigned PhysReg = tryAssign(VirtReg, Order, NewVRegs))
<< " Cascade " << ExtraRegInfo[VirtReg.reg].Cascade << '\n');
// Try to evict a less worthy live range, but only for ranges from the primary
- // queue. The RS_Second ranges already failed to do this, and they should not
+ // queue. The RS_Split ranges already failed to do this, and they should not
// get a second chance until they have been split.
- if (Stage != RS_Second)
+ if (Stage != RS_Split)
if (unsigned PhysReg = tryEvict(VirtReg, Order, NewVRegs))
return PhysReg;
// The first time we see a live range, don't try to split or spill.
// Wait until the second time, when all smaller ranges have been allocated.
// This gives a better picture of the interference to split around.
- if (Stage == RS_First) {
- setStage(VirtReg, RS_Second);
+ if (Stage < RS_Split) {
+ setStage(VirtReg, RS_Split);
DEBUG(dbgs() << "wait for second round\n");
NewVRegs.push_back(&VirtReg);
return 0;
// If we couldn't allocate a register from spilling, there is probably some
// invalid inline assembly. The base class wil report it.
- if (Stage >= RS_Spill || !VirtReg.isSpillable())
+ if (Stage >= RS_Done || !VirtReg.isSpillable())
return ~0u;
// Try splitting VirtReg or interferences.
NamedRegionTimer T("Spiller", TimerGroupName, TimePassesIsEnabled);
LiveRangeEdit LRE(VirtReg, NewVRegs, this);
spiller().spill(LRE);
- setStage(NewVRegs.begin(), NewVRegs.end(), RS_Spill);
+ setStage(NewVRegs.begin(), NewVRegs.end(), RS_Done);
if (VerifyEnabled)
MF->verify(this, "After spilling");
DomTree = &getAnalysis<MachineDominatorTree>();
SpillerInstance.reset(createInlineSpiller(*this, *MF, *VRM));
Loops = &getAnalysis<MachineLoopInfo>();
- LoopRanges = &getAnalysis<MachineLoopRanges>();
Bundles = &getAnalysis<EdgeBundles>();
SpillPlacer = &getAnalysis<SpillPlacement>();
DebugVars = &getAnalysis<LiveDebugVariables>();
ExtraRegInfo.clear();
ExtraRegInfo.resize(MRI->getNumVirtRegs());
NextCascade = 1;
- IntfCache.init(MF, &PhysReg2LiveUnion[0], Indexes, TRI);
+ IntfCache.init(MF, &getLiveUnion(0), Indexes, TRI);
+ GlobalCand.resize(32); // This will grow as needed.
allocatePhysRegs();
addMBBLiveIns(MF);
}
// Write out new DBG_VALUE instructions.
- DebugVars->emitDebugValues(VRM);
+ {
+ NamedRegionTimer T("Emit Debug Info", TimerGroupName, TimePassesIsEnabled);
+ DebugVars->emitDebugValues(VRM);
+ }
// The pass output is in VirtRegMap. Release all the transient data.
releaseMemory();
projects / oota-llvm.git / blobdiff