//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "regalloc"
+#include "llvm/CodeGen/Passes.h"
#include "AllocationOrder.h"
-#include "LiveIntervalUnion.h"
-#include "LiveRangeEdit.h"
+#include "InterferenceCache.h"
+#include "LiveDebugVariables.h"
#include "RegAllocBase.h"
-#include "Spiller.h"
#include "SpillPlacement.h"
+#include "Spiller.h"
#include "SplitKit.h"
-#include "VirtRegMap.h"
-#include "VirtRegRewriter.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Function.h"
-#include "llvm/PassAnalysisSupport.h"
#include "llvm/CodeGen/CalcSpillWeights.h"
#include "llvm/CodeGen/EdgeBundles.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/LiveRangeEdit.h"
+#include "llvm/CodeGen/LiveRegMatrix.h"
#include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/MachineBlockFrequencyInfo.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/CodeGen/RegisterCoalescer.h"
-#include "llvm/Target/TargetOptions.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
+#include "llvm/CodeGen/VirtRegMap.h"
+#include "llvm/PassAnalysisSupport.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <queue>
using namespace llvm;
+STATISTIC(NumGlobalSplits, "Number of split global live ranges");
+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 cl::opt<unsigned>
+LastChanceRecoloringMaxDepth("lcr-max-depth", cl::Hidden,
+ cl::desc("Last chance recoloring max depth"),
+ cl::init(5));
+
+static cl::opt<unsigned> LastChanceRecoloringMaxInterference(
+ "lcr-max-interf", cl::Hidden,
+ cl::desc("Last chance recoloring maximum number of considered"
+ " interference at a time"),
+ cl::init(8));
+
static RegisterRegAlloc greedyRegAlloc("greedy", "greedy register allocator",
createGreedyRegisterAllocator);
namespace {
-class RAGreedy : public MachineFunctionPass, public RegAllocBase {
+class RAGreedy : public MachineFunctionPass,
+ public RegAllocBase,
+ private LiveRangeEdit::Delegate {
+ // Convenient shortcuts.
+ typedef std::priority_queue<std::pair<unsigned, unsigned> > PQueue;
+ typedef SmallPtrSet<LiveInterval *, 4> SmallLISet;
+ typedef SmallSet<unsigned, 16> SmallVirtRegSet;
+
// context
MachineFunction *MF;
- BitVector ReservedRegs;
+
+ // Shortcuts to some useful interface.
+ const TargetInstrInfo *TII;
+ const TargetRegisterInfo *TRI;
+ RegisterClassInfo RCI;
// analyses
SlotIndexes *Indexes;
- LiveStacks *LS;
+ MachineBlockFrequencyInfo *MBFI;
MachineDominatorTree *DomTree;
MachineLoopInfo *Loops;
- MachineLoopRanges *LoopRanges;
EdgeBundles *Bundles;
SpillPlacement *SpillPlacer;
+ LiveDebugVariables *DebugVars;
// state
- std::auto_ptr<Spiller> SpillerInstance;
- std::auto_ptr<SplitAnalysis> SA;
+ OwningPtr<Spiller> SpillerInstance;
+ PQueue Queue;
+ unsigned NextCascade;
+
+ // Live ranges pass through a number of stages as we try to allocate them.
+ // Some of the stages may also create new live ranges:
+ //
+ // - Region splitting.
+ // - Per-block splitting.
+ // - Local splitting.
+ // - Spilling.
+ //
+ // Ranges produced by one of the stages skip the previous stages when they are
+ // dequeued. This improves performance because we can skip interference checks
+ // that are unlikely to give any results. It also guarantees that the live
+ // range splitting algorithm terminates, something that is otherwise hard to
+ // ensure.
+ enum LiveRangeStage {
+ /// 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
+ };
+
+#ifndef NDEBUG
+ static const char *const StageName[];
+#endif
+
+ // RegInfo - Keep additional information about each live range.
+ struct RegInfo {
+ LiveRangeStage Stage;
+
+ // Cascade - Eviction loop prevention. See canEvictInterference().
+ unsigned Cascade;
+
+ RegInfo() : Stage(RS_New), Cascade(0) {}
+ };
+
+ IndexedMap<RegInfo, VirtReg2IndexFunctor> ExtraRegInfo;
+
+ LiveRangeStage getStage(const LiveInterval &VirtReg) const {
+ return ExtraRegInfo[VirtReg.reg].Stage;
+ }
+
+ void setStage(const LiveInterval &VirtReg, LiveRangeStage Stage) {
+ ExtraRegInfo.resize(MRI->getNumVirtRegs());
+ ExtraRegInfo[VirtReg.reg].Stage = Stage;
+ }
+
+ template<typename Iterator>
+ void setStage(Iterator Begin, Iterator End, LiveRangeStage NewStage) {
+ ExtraRegInfo.resize(MRI->getNumVirtRegs());
+ for (;Begin != End; ++Begin) {
+ unsigned Reg = *Begin;
+ if (ExtraRegInfo[Reg].Stage == RS_New)
+ ExtraRegInfo[Reg].Stage = NewStage;
+ }
+ }
+
+ /// Cost of evicting interference.
+ struct EvictionCost {
+ unsigned BrokenHints; ///< Total number of broken hints.
+ float MaxWeight; ///< Maximum spill weight evicted.
+
+ EvictionCost(): BrokenHints(0), MaxWeight(0) {}
+
+ bool isMax() const { return BrokenHints == ~0u; }
+
+ void setMax() { BrokenHints = ~0u; }
+
+ void setBrokenHints(unsigned NHints) { BrokenHints = NHints; }
+
+ bool operator<(const EvictionCost &O) const {
+ if (BrokenHints != O.BrokenHints)
+ return BrokenHints < O.BrokenHints;
+ return MaxWeight < O.MaxWeight;
+ }
+ };
// splitting state.
+ OwningPtr<SplitAnalysis> SA;
+ OwningPtr<SplitEditor> SE;
+
+ /// Cached per-block interference maps
+ InterferenceCache IntfCache;
+
+ /// All basic blocks where the current register has uses.
+ SmallVector<SpillPlacement::BlockConstraint, 8> SplitConstraints;
- /// All basic blocks where the current register is live.
- SmallVector<SpillPlacement::BlockConstraint, 8> SpillConstraints;
-
- /// Additional information about basic blocks where the current variable is
- /// live. Such a block will look like one of these templates:
- ///
- /// 1. | o---x | Internal to block. Variable is only live in this block.
- /// 2. |---x | Live-in, kill.
- /// 3. | o---| Def, live-out.
- /// 4. |---x o---| Live-in, kill, def, live-out.
- /// 5. |---o---o---| Live-through with uses or defs.
- /// 6. |-----------| Live-through without uses. Transparent.
- ///
- struct BlockInfo {
- MachineBasicBlock *MBB;
- SlotIndex FirstUse; ///< First instr using current reg.
- SlotIndex LastUse; ///< Last instr using current reg.
- SlotIndex Kill; ///< Interval end point inside block.
- SlotIndex Def; ///< Interval start point inside block.
- bool Uses; ///< Current reg has uses or defs in block.
- bool LiveThrough; ///< Live in whole block (Templ 5. or 6. above).
- bool LiveIn; ///< Current reg is live in.
- bool LiveOut; ///< Current reg is live out.
-
- // Per-interference pattern scratch data.
- bool OverlapEntry; ///< Interference overlaps entering interval.
- bool OverlapExit; ///< Interference overlaps exiting interval.
+ /// 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;
+ }
};
- /// Basic blocks where var is live. This array is parallel to
- /// SpillConstraints.
- SmallVector<BlockInfo, 8> LiveBlocks;
+ /// Candidate info for each PhysReg in AllocationOrder.
+ /// This vector never shrinks, but grows to the size of the largest register
+ /// class.
+ SmallVector<GlobalSplitCandidate, 32> GlobalCand;
+
+ enum LLVM_ENUM_INT_TYPE(unsigned) { 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();
/// RAGreedy analysis usage.
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-
virtual void releaseMemory();
-
virtual Spiller &spiller() { return *SpillerInstance; }
-
- virtual float getPriority(LiveInterval *LI);
-
+ virtual void enqueue(LiveInterval *LI);
+ virtual LiveInterval *dequeue();
virtual unsigned selectOrSplit(LiveInterval&,
- SmallVectorImpl<LiveInterval*>&);
+ SmallVectorImpl<unsigned>&);
/// Perform register allocation.
virtual bool runOnMachineFunction(MachineFunction &mf);
static char ID;
private:
- bool checkUncachedInterference(LiveInterval&, unsigned);
- LiveInterval *getSingleInterference(LiveInterval&, unsigned);
- bool reassignVReg(LiveInterval &InterferingVReg, unsigned OldPhysReg);
- bool reassignInterferences(LiveInterval &VirtReg, unsigned PhysReg);
- float calcInterferenceWeight(LiveInterval&, unsigned);
- void calcLiveBlockInfo(LiveInterval&);
- float calcInterferenceInfo(LiveInterval&, unsigned);
- float calcGlobalSplitCost(const BitVector&);
- void splitAroundRegion(LiveInterval&, unsigned, const BitVector&,
- SmallVectorImpl<LiveInterval*>&);
-
- unsigned tryReassign(LiveInterval&, AllocationOrder&);
+ unsigned selectOrSplitImpl(LiveInterval &, SmallVectorImpl<unsigned> &,
+ SmallVirtRegSet &, unsigned = 0);
+
+ bool LRE_CanEraseVirtReg(unsigned);
+ void LRE_WillShrinkVirtReg(unsigned);
+ void LRE_DidCloneVirtReg(unsigned, unsigned);
+ void enqueue(PQueue &CurQueue, LiveInterval *LI);
+ LiveInterval *dequeue(PQueue &CurQueue);
+
+ BlockFrequency calcSpillCost();
+ bool addSplitConstraints(InterferenceCache::Cursor, BlockFrequency&);
+ void addThroughConstraints(InterferenceCache::Cursor, ArrayRef<unsigned>);
+ void growRegion(GlobalSplitCandidate &Cand);
+ BlockFrequency calcGlobalSplitCost(GlobalSplitCandidate&);
+ bool calcCompactRegion(GlobalSplitCandidate&);
+ void splitAroundRegion(LiveRangeEdit&, ArrayRef<unsigned>);
+ void calcGapWeights(unsigned, SmallVectorImpl<float>&);
+ unsigned canReassign(LiveInterval &VirtReg, unsigned PhysReg);
+ bool shouldEvict(LiveInterval &A, bool, LiveInterval &B, bool);
+ bool canEvictInterference(LiveInterval&, unsigned, bool, EvictionCost&);
+ void evictInterference(LiveInterval&, unsigned,
+ SmallVectorImpl<unsigned>&);
+ bool mayRecolorAllInterferences(unsigned PhysReg, LiveInterval &VirtReg,
+ SmallLISet &RecoloringCandidates,
+ const SmallVirtRegSet &FixedRegisters);
+
+ unsigned tryAssign(LiveInterval&, AllocationOrder&,
+ SmallVectorImpl<unsigned>&);
+ unsigned tryEvict(LiveInterval&, AllocationOrder&,
+ SmallVectorImpl<unsigned>&, unsigned = ~0u);
unsigned tryRegionSplit(LiveInterval&, AllocationOrder&,
- SmallVectorImpl<LiveInterval*>&);
+ SmallVectorImpl<unsigned>&);
+ unsigned tryBlockSplit(LiveInterval&, AllocationOrder&,
+ SmallVectorImpl<unsigned>&);
+ unsigned tryInstructionSplit(LiveInterval&, AllocationOrder&,
+ SmallVectorImpl<unsigned>&);
+ unsigned tryLocalSplit(LiveInterval&, AllocationOrder&,
+ SmallVectorImpl<unsigned>&);
unsigned trySplit(LiveInterval&, AllocationOrder&,
- SmallVectorImpl<LiveInterval*>&);
- unsigned trySpillInterferences(LiveInterval&, AllocationOrder&,
- SmallVectorImpl<LiveInterval*>&);
+ SmallVectorImpl<unsigned>&);
+ unsigned tryLastChanceRecoloring(LiveInterval &, AllocationOrder &,
+ SmallVectorImpl<unsigned> &,
+ SmallVirtRegSet &, unsigned);
+ bool tryRecoloringCandidates(PQueue &, SmallVectorImpl<unsigned> &,
+ SmallVirtRegSet &, unsigned);
};
} // end anonymous namespace
char RAGreedy::ID = 0;
+#ifndef NDEBUG
+const char *const RAGreedy::StageName[] = {
+ "RS_New",
+ "RS_Assign",
+ "RS_Split",
+ "RS_Split2",
+ "RS_Spill",
+ "RS_Done"
+};
+#endif
+
+// Hysteresis to use when comparing floats.
+// This helps stabilize decisions based on float comparisons.
+const float Hysteresis = (2007 / 2048.0f); // 0.97998046875
+
+
FunctionPass* llvm::createGreedyRegisterAllocator() {
return new RAGreedy();
}
RAGreedy::RAGreedy(): MachineFunctionPass(ID) {
+ initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
- initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry());
- initializeRegisterCoalescerAnalysisGroup(*PassRegistry::getPassRegistry());
- initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
+ initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry());
+ initializeMachineSchedulerPass(*PassRegistry::getPassRegistry());
initializeLiveStacksPass(*PassRegistry::getPassRegistry());
initializeMachineDominatorTreePass(*PassRegistry::getPassRegistry());
initializeMachineLoopInfoPass(*PassRegistry::getPassRegistry());
- initializeMachineLoopRangesPass(*PassRegistry::getPassRegistry());
initializeVirtRegMapPass(*PassRegistry::getPassRegistry());
+ initializeLiveRegMatrixPass(*PassRegistry::getPassRegistry());
initializeEdgeBundlesPass(*PassRegistry::getPassRegistry());
initializeSpillPlacementPass(*PassRegistry::getPassRegistry());
}
void RAGreedy::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
+ AU.addRequired<MachineBlockFrequencyInfo>();
+ AU.addPreserved<MachineBlockFrequencyInfo>();
AU.addRequired<AliasAnalysis>();
AU.addPreserved<AliasAnalysis>();
AU.addRequired<LiveIntervals>();
+ AU.addPreserved<LiveIntervals>();
AU.addRequired<SlotIndexes>();
AU.addPreserved<SlotIndexes>();
- if (StrongPHIElim)
- AU.addRequiredID(StrongPHIEliminationID);
- AU.addRequiredTransitive<RegisterCoalescer>();
- AU.addRequired<CalculateSpillWeights>();
+ AU.addRequired<LiveDebugVariables>();
+ AU.addPreserved<LiveDebugVariables>();
AU.addRequired<LiveStacks>();
AU.addPreserved<LiveStacks>();
AU.addRequired<MachineDominatorTree>();
AU.addPreserved<MachineDominatorTree>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineLoopInfo>();
- AU.addRequired<MachineLoopRanges>();
- AU.addPreserved<MachineLoopRanges>();
AU.addRequired<VirtRegMap>();
AU.addPreserved<VirtRegMap>();
+ AU.addRequired<LiveRegMatrix>();
+ AU.addPreserved<LiveRegMatrix>();
AU.addRequired<EdgeBundles>();
AU.addRequired<SpillPlacement>();
MachineFunctionPass::getAnalysisUsage(AU);
}
+
+//===----------------------------------------------------------------------===//
+// LiveRangeEdit delegate methods
+//===----------------------------------------------------------------------===//
+
+bool RAGreedy::LRE_CanEraseVirtReg(unsigned VirtReg) {
+ if (VRM->hasPhys(VirtReg)) {
+ Matrix->unassign(LIS->getInterval(VirtReg));
+ return true;
+ }
+ // Unassigned virtreg is probably in the priority queue.
+ // RegAllocBase will erase it after dequeueing.
+ return false;
+}
+
+void RAGreedy::LRE_WillShrinkVirtReg(unsigned VirtReg) {
+ if (!VRM->hasPhys(VirtReg))
+ return;
+
+ // Register is assigned, put it back on the queue for reassignment.
+ LiveInterval &LI = LIS->getInterval(VirtReg);
+ Matrix->unassign(LI);
+ enqueue(&LI);
+}
+
+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. 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];
+}
+
void RAGreedy::releaseMemory() {
SpillerInstance.reset(0);
- RegAllocBase::releaseMemory();
+ ExtraRegInfo.clear();
+ GlobalCand.clear();
}
-float RAGreedy::getPriority(LiveInterval *LI) {
- float Priority = LI->weight;
-
- // Prioritize hinted registers so they are allocated first.
- std::pair<unsigned, unsigned> Hint;
- if (Hint.first || Hint.second) {
- // The hint can be target specific, a virtual register, or a physreg.
- Priority *= 2;
+void RAGreedy::enqueue(LiveInterval *LI) { enqueue(Queue, LI); }
+
+void RAGreedy::enqueue(PQueue &CurQueue, LiveInterval *LI) {
+ // Prioritize live ranges by size, assigning larger ranges first.
+ // The queue holds (size, reg) pairs.
+ const unsigned Size = LI->getSize();
+ const unsigned Reg = LI->reg;
+ assert(TargetRegisterInfo::isVirtualRegister(Reg) &&
+ "Can only enqueue virtual registers");
+ unsigned Prio;
+
+ ExtraRegInfo.grow(Reg);
+ if (ExtraRegInfo[Reg].Stage == RS_New)
+ ExtraRegInfo[Reg].Stage = RS_Assign;
+
+ if (ExtraRegInfo[Reg].Stage == RS_Split) {
+ // Unsplit ranges that couldn't be allocated immediately are deferred until
+ // everything else has been allocated.
+ Prio = Size;
+ } else {
+ if (ExtraRegInfo[Reg].Stage == RS_Assign && !LI->empty() &&
+ LIS->intervalIsInOneMBB(*LI)) {
+ // Allocate original local ranges in linear instruction order. Since they
+ // are singly defined, this produces optimal coloring in the absence of
+ // global interference and other constraints.
+ if (!TRI->reverseLocalAssignment())
+ Prio = LI->beginIndex().getInstrDistance(Indexes->getLastIndex());
+ else {
+ // Allocating bottom up may allow many short LRGs to be assigned first
+ // to one of the cheap registers. This could be much faster for very
+ // large blocks on targets with many physical registers.
+ Prio = Indexes->getZeroIndex().getInstrDistance(LI->beginIndex());
+ }
+ }
+ else {
+ // Allocate global and split ranges in long->short order. Long ranges that
+ // don't fit should be spilled (or split) ASAP so they don't create
+ // interference. Mark a bit to prioritize global above local ranges.
+ Prio = (1u << 29) + Size;
+ }
+ // Mark a higher bit to prioritize global and local above RS_Split.
+ Prio |= (1u << 31);
- // Prefer physreg hints above anything else.
- if (Hint.first == 0 && TargetRegisterInfo::isPhysicalRegister(Hint.second))
- Priority *= 2;
+ // Boost ranges that have a physical register hint.
+ if (VRM->hasKnownPreference(Reg))
+ Prio |= (1u << 30);
}
- return Priority;
+ // The virtual register number is a tie breaker for same-sized ranges.
+ // Give lower vreg numbers higher priority to assign them first.
+ CurQueue.push(std::make_pair(Prio, ~Reg));
+}
+
+LiveInterval *RAGreedy::dequeue() { return dequeue(Queue); }
+
+LiveInterval *RAGreedy::dequeue(PQueue &CurQueue) {
+ if (CurQueue.empty())
+ return 0;
+ LiveInterval *LI = &LIS->getInterval(~CurQueue.top().second);
+ CurQueue.pop();
+ return LI;
}
//===----------------------------------------------------------------------===//
-// Register Reassignment
+// Direct Assignment
//===----------------------------------------------------------------------===//
-// Check interference without using the cache.
-bool RAGreedy::checkUncachedInterference(LiveInterval &VirtReg,
- unsigned PhysReg) {
- for (const unsigned *AliasI = TRI->getOverlaps(PhysReg); *AliasI; ++AliasI) {
- LiveIntervalUnion::Query subQ(&VirtReg, &PhysReg2LiveUnion[*AliasI]);
- if (subQ.checkInterference())
- return true;
- }
- return false;
-}
+/// tryAssign - Try to assign VirtReg to an available register.
+unsigned RAGreedy::tryAssign(LiveInterval &VirtReg,
+ AllocationOrder &Order,
+ SmallVectorImpl<unsigned> &NewVRegs) {
+ Order.rewind();
+ unsigned PhysReg;
+ while ((PhysReg = Order.next()))
+ if (!Matrix->checkInterference(VirtReg, PhysReg))
+ break;
+ if (!PhysReg || Order.isHint())
+ return PhysReg;
-/// getSingleInterference - Return the single interfering virtual register
-/// assigned to PhysReg. Return 0 if more than one virtual register is
-/// interfering.
-LiveInterval *RAGreedy::getSingleInterference(LiveInterval &VirtReg,
- unsigned PhysReg) {
- // Check physreg and aliases.
- LiveInterval *Interference = 0;
- for (const unsigned *AliasI = TRI->getOverlaps(PhysReg); *AliasI; ++AliasI) {
- LiveIntervalUnion::Query &Q = query(VirtReg, *AliasI);
- if (Q.checkInterference()) {
- if (Interference)
- return 0;
- Q.collectInterferingVRegs(1);
- if (!Q.seenAllInterferences())
- return 0;
- Interference = Q.interferingVRegs().front();
+ // PhysReg is available, but there may be a better choice.
+
+ // 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)) {
+ DEBUG(dbgs() << "missed hint " << PrintReg(Hint, TRI) << '\n');
+ EvictionCost MaxCost;
+ MaxCost.setBrokenHints(1);
+ if (canEvictInterference(VirtReg, Hint, true, MaxCost)) {
+ evictInterference(VirtReg, Hint, NewVRegs);
+ return Hint;
+ }
}
- }
- return Interference;
+
+ // Try to evict interference from a cheaper alternative.
+ unsigned Cost = TRI->getCostPerUse(PhysReg);
+
+ // Most registers have 0 additional cost.
+ if (!Cost)
+ return PhysReg;
+
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << " is available at cost " << Cost
+ << '\n');
+ unsigned CheapReg = tryEvict(VirtReg, Order, NewVRegs, Cost);
+ return CheapReg ? CheapReg : PhysReg;
}
-// Attempt to reassign this virtual register to a different physical register.
-//
-// FIXME: we are not yet caching these "second-level" interferences discovered
-// in the sub-queries. These interferences can change with each call to
-// selectOrSplit. However, we could implement a "may-interfere" cache that
-// could be conservatively dirtied when we reassign or split.
-//
-// FIXME: This may result in a lot of alias queries. We could summarize alias
-// live intervals in their parent register's live union, but it's messy.
-bool RAGreedy::reassignVReg(LiveInterval &InterferingVReg,
- unsigned WantedPhysReg) {
- assert(TargetRegisterInfo::isVirtualRegister(InterferingVReg.reg) &&
- "Can only reassign virtual registers");
- assert(TRI->regsOverlap(WantedPhysReg, VRM->getPhys(InterferingVReg.reg)) &&
- "inconsistent phys reg assigment");
-
- AllocationOrder Order(InterferingVReg.reg, *VRM, ReservedRegs);
- while (unsigned PhysReg = Order.next()) {
- // Don't reassign to a WantedPhysReg alias.
- if (TRI->regsOverlap(PhysReg, WantedPhysReg))
- continue;
- if (checkUncachedInterference(InterferingVReg, PhysReg))
+//===----------------------------------------------------------------------===//
+// Interference eviction
+//===----------------------------------------------------------------------===//
+
+unsigned RAGreedy::canReassign(LiveInterval &VirtReg, unsigned PrevReg) {
+ AllocationOrder Order(VirtReg.reg, *VRM, RegClassInfo);
+ unsigned PhysReg;
+ while ((PhysReg = Order.next())) {
+ if (PhysReg == PrevReg)
continue;
- // Reassign the interfering virtual reg to this physical reg.
- unsigned OldAssign = VRM->getPhys(InterferingVReg.reg);
- DEBUG(dbgs() << "reassigning: " << InterferingVReg << " from " <<
- TRI->getName(OldAssign) << " to " << TRI->getName(PhysReg) << '\n');
- PhysReg2LiveUnion[OldAssign].extract(InterferingVReg);
- VRM->clearVirt(InterferingVReg.reg);
- VRM->assignVirt2Phys(InterferingVReg.reg, PhysReg);
- PhysReg2LiveUnion[PhysReg].unify(InterferingVReg);
+ MCRegUnitIterator Units(PhysReg, TRI);
+ for (; Units.isValid(); ++Units) {
+ // Instantiate a "subquery", not to be confused with the Queries array.
+ LiveIntervalUnion::Query subQ(&VirtReg, &Matrix->getLiveUnions()[*Units]);
+ if (subQ.checkInterference())
+ break;
+ }
+ // If no units have interference, break out with the current PhysReg.
+ if (!Units.isValid())
+ break;
+ }
+ if (PhysReg)
+ DEBUG(dbgs() << "can reassign: " << VirtReg << " from "
+ << PrintReg(PrevReg, TRI) << " to " << PrintReg(PhysReg, TRI)
+ << '\n');
+ return PhysReg;
+}
+
+/// shouldEvict - determine if A should evict the assigned live range B. The
+/// eviction policy defined by this function together with the allocation order
+/// defined by enqueue() decides which registers ultimately end up being split
+/// and spilled.
+///
+/// Cascade numbers are used to prevent infinite loops if this function is a
+/// cyclic relation.
+///
+/// @param A The live range to be assigned.
+/// @param IsHint True when A is about to be assigned to its preferred
+/// register.
+/// @param B The live range to be evicted.
+/// @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_Spill;
+
+ // Be fairly aggressive about following hints as long as the evictee can be
+ // split.
+ if (CanSplit && IsHint && !BreaksHint)
+ return true;
+ if (A.weight > B.weight) {
+ DEBUG(dbgs() << "should evict: " << B << " w= " << B.weight << '\n');
return true;
}
return false;
}
-/// reassignInterferences - Reassign all interferences to different physical
-/// registers such that Virtreg can be assigned to PhysReg.
-/// Currently this only works with a single interference.
-/// @param VirtReg Currently unassigned virtual register.
-/// @param PhysReg Physical register to be cleared.
-/// @return True on success, false if nothing was changed.
-bool RAGreedy::reassignInterferences(LiveInterval &VirtReg, unsigned PhysReg) {
- LiveInterval *InterferingVReg = getSingleInterference(VirtReg, PhysReg);
- if (!InterferingVReg)
- return false;
- if (TargetRegisterInfo::isPhysicalRegister(InterferingVReg->reg))
+/// canEvictInterference - Return true if all interferences between VirtReg and
+/// PhysReg can be evicted. When OnlyCheap is set, don't do anything
+///
+/// @param VirtReg Live range that is about to be assigned.
+/// @param PhysReg Desired register for assignment.
+/// @param IsHint True when PhysReg is VirtReg's preferred register.
+/// @param MaxCost Only look for cheaper candidates and update with new cost
+/// when returning true.
+/// @returns True when interference can be evicted cheaper than MaxCost.
+bool RAGreedy::canEvictInterference(LiveInterval &VirtReg, unsigned PhysReg,
+ bool IsHint, EvictionCost &MaxCost) {
+ // It is only possible to evict virtual register interference.
+ if (Matrix->checkInterference(VirtReg, PhysReg) > LiveRegMatrix::IK_VirtReg)
return false;
- return reassignVReg(*InterferingVReg, PhysReg);
+
+ bool IsLocal = LIS->intervalIsInOneMBB(VirtReg);
+
+ // Find VirtReg's cascade number. This will be unassigned if VirtReg was never
+ // involved in an eviction before. If a cascade number was assigned, deny
+ // evicting anything with the same or a newer cascade number. This prevents
+ // infinite eviction loops.
+ //
+ // This works out so a register without a cascade number is allowed to evict
+ // anything, and it can be evicted by anything.
+ unsigned Cascade = ExtraRegInfo[VirtReg.reg].Cascade;
+ if (!Cascade)
+ Cascade = NextCascade;
+
+ EvictionCost Cost;
+ for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+ LiveIntervalUnion::Query &Q = Matrix->query(VirtReg, *Units);
+ // If there is 10 or more interferences, chances are one is heavier.
+ if (Q.collectInterferingVRegs(10) >= 10)
+ return false;
+
+ // Check if any interfering live range is heavier than MaxWeight.
+ for (unsigned i = Q.interferingVRegs().size(); i; --i) {
+ LiveInterval *Intf = Q.interferingVRegs()[i - 1];
+ assert(TargetRegisterInfo::isVirtualRegister(Intf->reg) &&
+ "Only expecting virtual register interference from query");
+ // Never evict spill products. They cannot split or 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
+ // urgent live ranges get to evict almost anything.
+ //
+ // Also allow urgent evictions of unspillable ranges from a strictly
+ // larger allocation order.
+ bool Urgent = !VirtReg.isSpillable() &&
+ (Intf->isSpillable() ||
+ RegClassInfo.getNumAllocatableRegs(MRI->getRegClass(VirtReg.reg)) <
+ RegClassInfo.getNumAllocatableRegs(MRI->getRegClass(Intf->reg)));
+ // Only evict older cascades or live ranges without a cascade.
+ unsigned IntfCascade = ExtraRegInfo[Intf->reg].Cascade;
+ if (Cascade <= IntfCascade) {
+ if (!Urgent)
+ return false;
+ // We permit breaking cascades for urgent evictions. It should be the
+ // last resort, though, so make it really expensive.
+ Cost.BrokenHints += 10;
+ }
+ // Would this break a satisfied hint?
+ bool BreaksHint = VRM->hasPreferredPhys(Intf->reg);
+ // Update eviction cost.
+ Cost.BrokenHints += BreaksHint;
+ Cost.MaxWeight = std::max(Cost.MaxWeight, Intf->weight);
+ // Abort if this would be too expensive.
+ if (!(Cost < MaxCost))
+ return false;
+ if (Urgent)
+ continue;
+ // Apply the eviction policy for non-urgent evictions.
+ if (!shouldEvict(VirtReg, IsHint, *Intf, BreaksHint))
+ return false;
+ // If !MaxCost.isMax(), then we're just looking for a cheap register.
+ // Evicting another local live range in this case could lead to suboptimal
+ // coloring.
+ if (!MaxCost.isMax() && IsLocal && LIS->intervalIsInOneMBB(*Intf) &&
+ !canReassign(*Intf, PhysReg)) {
+ return false;
+ }
+ }
+ }
+ MaxCost = Cost;
+ return true;
+}
+
+/// evictInterference - Evict any interferring registers that prevent VirtReg
+/// from being assigned to Physreg. This assumes that canEvictInterference
+/// returned true.
+void RAGreedy::evictInterference(LiveInterval &VirtReg, unsigned PhysReg,
+ SmallVectorImpl<unsigned> &NewVRegs) {
+ // Make sure that VirtReg has a cascade number, and assign that cascade
+ // number to every evicted register. These live ranges than then only be
+ // evicted by a newer cascade, preventing infinite loops.
+ unsigned Cascade = ExtraRegInfo[VirtReg.reg].Cascade;
+ if (!Cascade)
+ Cascade = ExtraRegInfo[VirtReg.reg].Cascade = NextCascade++;
+
+ DEBUG(dbgs() << "evicting " << PrintReg(PhysReg, TRI)
+ << " interference: Cascade " << Cascade << '\n');
+
+ // Collect all interfering virtregs first.
+ SmallVector<LiveInterval*, 8> Intfs;
+ for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+ LiveIntervalUnion::Query &Q = Matrix->query(VirtReg, *Units);
+ assert(Q.seenAllInterferences() && "Didn't check all interfererences.");
+ ArrayRef<LiveInterval*> IVR = Q.interferingVRegs();
+ Intfs.append(IVR.begin(), IVR.end());
+ }
+
+ // Evict them second. This will invalidate the queries.
+ for (unsigned i = 0, e = Intfs.size(); i != e; ++i) {
+ LiveInterval *Intf = Intfs[i];
+ // The same VirtReg may be present in multiple RegUnits. Skip duplicates.
+ if (!VRM->hasPhys(Intf->reg))
+ continue;
+ Matrix->unassign(*Intf);
+ assert((ExtraRegInfo[Intf->reg].Cascade < Cascade ||
+ VirtReg.isSpillable() < Intf->isSpillable()) &&
+ "Cannot decrease cascade number, illegal eviction");
+ ExtraRegInfo[Intf->reg].Cascade = Cascade;
+ ++NumEvicted;
+ NewVRegs.push_back(Intf->reg);
+ }
}
-/// tryReassign - Try to reassign interferences to different physregs.
+/// tryEvict - Try to evict all interferences for a physreg.
/// @param VirtReg Currently unassigned virtual register.
/// @param Order Physregs to try.
/// @return Physreg to assign VirtReg, or 0.
-unsigned RAGreedy::tryReassign(LiveInterval &VirtReg, AllocationOrder &Order) {
- NamedRegionTimer T("Reassign", TimerGroupName, TimePassesIsEnabled);
+unsigned RAGreedy::tryEvict(LiveInterval &VirtReg,
+ AllocationOrder &Order,
+ SmallVectorImpl<unsigned> &NewVRegs,
+ unsigned CostPerUseLimit) {
+ NamedRegionTimer T("Evict", TimerGroupName, TimePassesIsEnabled);
+
+ // Keep track of the cheapest interference seen so far.
+ EvictionCost BestCost;
+ BestCost.setMax();
+ unsigned BestPhys = 0;
+ unsigned OrderLimit = Order.getOrder().size();
+
+ // When we are just looking for a reduced cost per use, don't break any
+ // hints, and only evict smaller spill weights.
+ if (CostPerUseLimit < ~0u) {
+ BestCost.BrokenHints = 0;
+ BestCost.MaxWeight = VirtReg.weight;
+
+ // Check of any registers in RC are below CostPerUseLimit.
+ const TargetRegisterClass *RC = MRI->getRegClass(VirtReg.reg);
+ unsigned MinCost = RegClassInfo.getMinCost(RC);
+ if (MinCost >= CostPerUseLimit) {
+ DEBUG(dbgs() << RC->getName() << " minimum cost = " << MinCost
+ << ", no cheaper registers to be found.\n");
+ return 0;
+ }
+
+ // It is normal for register classes to have a long tail of registers with
+ // the same cost. We don't need to look at them if they're too expensive.
+ if (TRI->getCostPerUse(Order.getOrder().back()) >= CostPerUseLimit) {
+ OrderLimit = RegClassInfo.getLastCostChange(RC);
+ DEBUG(dbgs() << "Only trying the first " << OrderLimit << " regs.\n");
+ }
+ }
+
Order.rewind();
- while (unsigned PhysReg = Order.next())
- if (reassignInterferences(VirtReg, PhysReg))
- return PhysReg;
- return 0;
+ while (unsigned PhysReg = Order.next(OrderLimit)) {
+ if (TRI->getCostPerUse(PhysReg) >= CostPerUseLimit)
+ continue;
+ // The first use of a callee-saved register in a function has cost 1.
+ // Don't start using a CSR when the CostPerUseLimit is low.
+ if (CostPerUseLimit == 1)
+ if (unsigned CSR = RegClassInfo.getLastCalleeSavedAlias(PhysReg))
+ if (!MRI->isPhysRegUsed(CSR)) {
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << " would clobber CSR "
+ << PrintReg(CSR, TRI) << '\n');
+ continue;
+ }
+
+ if (!canEvictInterference(VirtReg, PhysReg, false, BestCost))
+ continue;
+
+ // Best so far.
+ BestPhys = PhysReg;
+
+ // Stop if the hint can be used.
+ if (Order.isHint())
+ break;
+ }
+
+ if (!BestPhys)
+ return 0;
+
+ evictInterference(VirtReg, BestPhys, NewVRegs);
+ return BestPhys;
}
// Region Splitting
//===----------------------------------------------------------------------===//
-/// calcLiveBlockInfo - Fill the LiveBlocks array with information about blocks
-/// where VirtReg is live.
-/// The SpillConstraints array is minimally initialized with MBB->getNumber().
-void RAGreedy::calcLiveBlockInfo(LiveInterval &VirtReg) {
- LiveBlocks.clear();
- SpillConstraints.clear();
-
- assert(!VirtReg.empty() && "Cannot allocate an empty interval");
- LiveInterval::const_iterator LVI = VirtReg.begin();
- LiveInterval::const_iterator LVE = VirtReg.end();
+/// addSplitConstraints - Fill out the SplitConstraints vector based on the
+/// 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.
+/// Return false if there are no bundles with positive bias.
+bool RAGreedy::addSplitConstraints(InterferenceCache::Cursor Intf,
+ BlockFrequency &Cost) {
+ ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
- SmallVectorImpl<SlotIndex>::const_iterator UseI, UseE;
- UseI = SA->UseSlots.begin();
- UseE = SA->UseSlots.end();
+ // Reset interference dependent info.
+ SplitConstraints.resize(UseBlocks.size());
+ BlockFrequency StaticCost = 0;
+ for (unsigned i = 0; i != UseBlocks.size(); ++i) {
+ const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
+ SpillPlacement::BlockConstraint &BC = SplitConstraints[i];
+
+ BC.Number = BI.MBB->getNumber();
+ Intf.moveToBlock(BC.Number);
+ BC.Entry = BI.LiveIn ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
+ BC.Exit = BI.LiveOut ? SpillPlacement::PrefReg : SpillPlacement::DontCare;
+ BC.ChangesValue = BI.FirstDef.isValid();
+
+ if (!Intf.hasInterference())
+ continue;
- // Loop over basic blocks where VirtReg is live.
- MachineFunction::iterator MFI = Indexes->getMBBFromIndex(LVI->start);
- for (;;) {
- // Block constraints depend on the interference pattern.
- // Just allocate them here, don't compute anything.
- SpillPlacement::BlockConstraint BC;
- BC.Number = MFI->getNumber();
- SpillConstraints.push_back(BC);
-
- BlockInfo BI;
- BI.MBB = MFI;
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
-
- // LVI is the first live segment overlapping MBB.
- BI.LiveIn = LVI->start <= Start;
- if (!BI.LiveIn)
- BI.Def = LVI->start;
-
- // Find the first and last uses in the block.
- BI.Uses = SA->hasUses(MFI);
- if (BI.Uses && UseI != UseE) {
- BI.FirstUse = *UseI;
- assert(BI.FirstUse >= Start);
- do ++UseI;
- while (UseI != UseE && *UseI < Stop);
- BI.LastUse = UseI[-1];
- assert(BI.LastUse < Stop);
- }
-
- // Look for gaps in the live range.
- bool hasGap = false;
- BI.LiveOut = true;
- while (LVI->end < Stop) {
- SlotIndex LastStop = LVI->end;
- if (++LVI == LVE || LVI->start >= Stop) {
- BI.Kill = LastStop;
- BI.LiveOut = false;
- break;
- }
- if (LastStop < LVI->start) {
- hasGap = true;
- BI.Kill = LastStop;
- BI.Def = LVI->start;
- }
+ // Number of spill code instructions to insert.
+ unsigned Ins = 0;
+
+ // Interference for the live-in value.
+ if (BI.LiveIn) {
+ if (Intf.first() <= Indexes->getMBBStartIdx(BC.Number))
+ BC.Entry = SpillPlacement::MustSpill, ++Ins;
+ else if (Intf.first() < BI.FirstInstr)
+ BC.Entry = SpillPlacement::PrefSpill, ++Ins;
+ else if (Intf.first() < BI.LastInstr)
+ ++Ins;
}
- // Don't set LiveThrough when the block has a gap.
- BI.LiveThrough = !hasGap && BI.LiveIn && BI.LiveOut;
- LiveBlocks.push_back(BI);
-
- // 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 == Stop && ++LVI == LVE)
- break;
+ // Interference for the live-out value.
+ if (BI.LiveOut) {
+ if (Intf.last() >= SA->getLastSplitPoint(BC.Number))
+ BC.Exit = SpillPlacement::MustSpill, ++Ins;
+ else if (Intf.last() > BI.LastInstr)
+ BC.Exit = SpillPlacement::PrefSpill, ++Ins;
+ else if (Intf.last() > BI.FirstInstr)
+ ++Ins;
+ }
- // Pick the next basic block.
- if (LVI->start < Stop)
- ++MFI;
- else
- MFI = Indexes->getMBBFromIndex(LVI->start);
+ // Accumulate the total frequency of inserted spill code.
+ while (Ins--)
+ StaticCost += 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);
+ return SpillPlacer->scanActiveBundles();
}
-/// calcInterferenceInfo - Compute per-block outgoing and ingoing constraints
-/// when considering interference from PhysReg. Also compute an optimistic local
-/// cost of this interference pattern.
-///
-/// The final cost of a split is the local cost + global cost of preferences
-/// broken by SpillPlacement.
-///
-float RAGreedy::calcInterferenceInfo(LiveInterval &VirtReg, unsigned PhysReg) {
- // Reset interference dependent info.
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- BlockInfo &BI = LiveBlocks[i];
- SpillPlacement::BlockConstraint &BC = SpillConstraints[i];
- BC.Entry = (BI.Uses && BI.LiveIn) ?
- SpillPlacement::PrefReg : SpillPlacement::DontCare;
- BC.Exit = (BI.Uses && BI.LiveOut) ?
- SpillPlacement::PrefReg : SpillPlacement::DontCare;
- BI.OverlapEntry = BI.OverlapExit = false;
- }
-
- // Add interference info from each PhysReg alias.
- for (const unsigned *AI = TRI->getOverlaps(PhysReg); *AI; ++AI) {
- if (!query(VirtReg, *AI).checkInterference())
- continue;
- DEBUG(PhysReg2LiveUnion[*AI].print(dbgs(), TRI));
- LiveIntervalUnion::SegmentIter IntI =
- PhysReg2LiveUnion[*AI].find(VirtReg.beginIndex());
- if (!IntI.valid())
+
+/// 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 TBS[GroupSize];
+ unsigned B = 0, T = 0;
+
+ for (unsigned i = 0; i != Blocks.size(); ++i) {
+ unsigned Number = Blocks[i];
+ Intf.moveToBlock(Number);
+
+ if (!Intf.hasInterference()) {
+ assert(T < GroupSize && "Array overflow");
+ TBS[T] = Number;
+ if (++T == GroupSize) {
+ SpillPlacer->addLinks(makeArrayRef(TBS, T));
+ T = 0;
+ }
continue;
+ }
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- BlockInfo &BI = LiveBlocks[i];
- SpillPlacement::BlockConstraint &BC = SpillConstraints[i];
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
+ assert(B < GroupSize && "Array overflow");
+ BCS[B].Number = Number;
- // Skip interference-free blocks.
- if (IntI.start() >= Stop)
- continue;
+ // Interference for the live-in value.
+ if (Intf.first() <= Indexes->getMBBStartIdx(Number))
+ BCS[B].Entry = SpillPlacement::MustSpill;
+ else
+ BCS[B].Entry = SpillPlacement::PrefSpill;
- // Handle transparent blocks with interference separately.
- // Transparent blocks never incur any fixed cost.
- if (BI.LiveThrough && !BI.Uses) {
- // Check if interference is live-in - force spill.
- if (BC.Entry != SpillPlacement::MustSpill) {
- BC.Entry = SpillPlacement::PrefSpill;
- IntI.advanceTo(Start);
- if (IntI.valid() && IntI.start() <= Start)
- BC.Entry = SpillPlacement::MustSpill;
- }
+ // Interference for the live-out value.
+ if (Intf.last() >= SA->getLastSplitPoint(Number))
+ BCS[B].Exit = SpillPlacement::MustSpill;
+ else
+ BCS[B].Exit = SpillPlacement::PrefSpill;
- // Check if interference is live-out - force spill.
- if (BC.Exit != SpillPlacement::MustSpill) {
- BC.Exit = SpillPlacement::PrefSpill;
- IntI.advanceTo(Stop);
- if (IntI.valid() && IntI.start() < Stop)
- BC.Exit = SpillPlacement::MustSpill;
- }
+ if (++B == GroupSize) {
+ ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
+ SpillPlacer->addConstraints(Array);
+ B = 0;
+ }
+ }
- // Nothing more to do for this transparent block.
- if (!IntI.valid())
- break;
- continue;
+ ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
+ SpillPlacer->addConstraints(Array);
+ SpillPlacer->addLinks(makeArrayRef(TBS, T));
+}
+
+void RAGreedy::growRegion(GlobalSplitCandidate &Cand) {
+ // 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();
+ // 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)
+ break;
- // Now we only have blocks with uses left.
- // Check if the interference overlaps the uses.
- assert(BI.Uses && "Non-transparent block without any uses");
+ // 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();
- // Check interference on entry.
- if (BI.LiveIn && BC.Entry != SpillPlacement::MustSpill) {
- IntI.advanceTo(Start);
- if (!IntI.valid())
- break;
+ // Perhaps iterating can enable more bundles?
+ SpillPlacer->iterate();
+ }
+ DEBUG(dbgs() << ", v=" << Visited);
+}
- // Interference is live-in - force spill.
- if (IntI.start() <= Start)
- BC.Entry = SpillPlacement::MustSpill;
- // Not live in, but before the first use.
- else if (IntI.start() < BI.FirstUse)
- BC.Entry = SpillPlacement::PrefSpill;
- }
+/// 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;
- // Does interference overlap the uses in the entry segment
- // [FirstUse;Kill)?
- if (BI.LiveIn && !BI.OverlapEntry) {
- IntI.advanceTo(BI.FirstUse);
- if (!IntI.valid())
- break;
- // A live-through interval has no kill.
- // Check [FirstUse;LastUse) instead.
- if (IntI.start() < (BI.LiveThrough ? BI.LastUse : BI.Kill))
- BI.OverlapEntry = true;
- }
+ // Compact regions don't correspond to any physreg.
+ Cand.reset(IntfCache, 0);
- // Does interference overlap the uses in the exit segment [Def;LastUse)?
- if (BI.LiveOut && !BI.LiveThrough && !BI.OverlapExit) {
- IntI.advanceTo(BI.Def);
- if (!IntI.valid())
- break;
- if (IntI.start() < BI.LastUse)
- BI.OverlapExit = true;
- }
+ DEBUG(dbgs() << "Compact region bundles");
- // Check interference on exit.
- if (BI.LiveOut && BC.Exit != SpillPlacement::MustSpill) {
- // Check interference between LastUse and Stop.
- if (BC.Exit != SpillPlacement::PrefSpill) {
- IntI.advanceTo(BI.LastUse);
- if (!IntI.valid())
- break;
- if (IntI.start() < Stop)
- BC.Exit = SpillPlacement::PrefSpill;
- }
- // Is the interference live-out?
- IntI.advanceTo(Stop);
- if (!IntI.valid())
- break;
- if (IntI.start() < Stop)
- BC.Exit = SpillPlacement::MustSpill;
- }
- }
+ // 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.
+ BlockFrequency Cost;
+ if (!addSplitConstraints(Cand.Intf, Cost)) {
+ DEBUG(dbgs() << ", none.\n");
+ return false;
}
- // Accumulate a local cost of this interference pattern.
- float LocalCost = 0;
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- BlockInfo &BI = LiveBlocks[i];
- if (!BI.Uses)
- continue;
- SpillPlacement::BlockConstraint &BC = SpillConstraints[i];
- unsigned Inserts = 0;
+ growRegion(Cand);
+ SpillPlacer->finish();
- // Do we need spill code for the entry segment?
- if (BI.LiveIn)
- Inserts += BI.OverlapEntry || BC.Entry != SpillPlacement::PrefReg;
+ if (!Cand.LiveBundles.any()) {
+ DEBUG(dbgs() << ", none.\n");
+ return false;
+ }
- // For the exit segment?
- if (BI.LiveOut)
- Inserts += BI.OverlapExit || BC.Exit != SpillPlacement::PrefReg;
+ DEBUG({
+ for (int i = Cand.LiveBundles.find_first(); i>=0;
+ i = Cand.LiveBundles.find_next(i))
+ dbgs() << " EB#" << i;
+ dbgs() << ".\n";
+ });
+ return true;
+}
- // The local cost of spill code in this block is the block frequency times
- // the number of spill instructions inserted.
- if (Inserts)
- LocalCost += Inserts * SpillPlacer->getBlockFrequency(BI.MBB);
+/// calcSpillCost - Compute how expensive it would be to split the live range in
+/// SA around all use blocks instead of forming bundle regions.
+BlockFrequency RAGreedy::calcSpillCost() {
+ BlockFrequency Cost = 0;
+ ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
+ for (unsigned i = 0; i != UseBlocks.size(); ++i) {
+ const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
+ unsigned Number = BI.MBB->getNumber();
+ // We normally only need one spill instruction - a load or a store.
+ Cost += SpillPlacer->getBlockFrequency(Number);
+
+ // Unless the value is redefined in the block.
+ if (BI.LiveIn && BI.LiveOut && BI.FirstDef)
+ Cost += SpillPlacer->getBlockFrequency(Number);
}
- DEBUG(dbgs() << "Local cost of " << PrintReg(PhysReg, TRI) << " = "
- << LocalCost << '\n');
- return LocalCost;
+ return Cost;
}
/// 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 SpillConstraints.
+/// interference pattern in SplitConstraints.
///
-float RAGreedy::calcGlobalSplitCost(const BitVector &LiveBundles) {
- float GlobalCost = 0;
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- SpillPlacement::BlockConstraint &BC = SpillConstraints[i];
- unsigned Inserts = 0;
- // Broken entry preference?
- Inserts += LiveBundles[Bundles->getBundle(BC.Number, 0)] !=
- (BC.Entry == SpillPlacement::PrefReg);
- // Broken exit preference?
- Inserts += LiveBundles[Bundles->getBundle(BC.Number, 1)] !=
- (BC.Exit == SpillPlacement::PrefReg);
- if (Inserts)
- GlobalCost += Inserts * SpillPlacer->getBlockFrequency(LiveBlocks[i].MBB);
- }
- DEBUG(dbgs() << "Global cost = " << GlobalCost << '\n');
+BlockFrequency RAGreedy::calcGlobalSplitCost(GlobalSplitCandidate &Cand) {
+ BlockFrequency 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];
+ SpillPlacement::BlockConstraint &BC = SplitConstraints[i];
+ bool RegIn = LiveBundles[Bundles->getBundle(BC.Number, 0)];
+ bool RegOut = LiveBundles[Bundles->getBundle(BC.Number, 1)];
+ unsigned Ins = 0;
+
+ if (BI.LiveIn)
+ Ins += RegIn != (BC.Entry == SpillPlacement::PrefReg);
+ if (BI.LiveOut)
+ Ins += RegOut != (BC.Exit == SpillPlacement::PrefReg);
+ while (Ins--)
+ GlobalCost += SpillPlacer->getBlockFrequency(BC.Number);
+ }
+
+ 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)
+ continue;
+ if (RegIn && RegOut) {
+ // We need double spill code if this block has interference.
+ Cand.Intf.moveToBlock(Number);
+ if (Cand.Intf.hasInterference()) {
+ GlobalCost += SpillPlacer->getBlockFrequency(Number);
+ GlobalCost += SpillPlacer->getBlockFrequency(Number);
+ }
+ continue;
+ }
+ // live-in / stack-out or stack-in live-out.
+ GlobalCost += SpillPlacer->getBlockFrequency(Number);
+ }
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, unsigned PhysReg,
- const BitVector &LiveBundles,
- SmallVectorImpl<LiveInterval*> &NewVRegs) {
- DEBUG({
- dbgs() << "Splitting around region for " << PrintReg(PhysReg, TRI)
- << " with bundles";
- for (int i = LiveBundles.find_first(); i>=0; i = LiveBundles.find_next(i))
- dbgs() << " EB#" << i;
- dbgs() << ".\n";
- });
+/// @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];
+ 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();
+ }
+ }
+ 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();
+ }
+ }
- // First compute interference ranges in the live blocks.
- typedef std::pair<SlotIndex, SlotIndex> IndexPair;
- SmallVector<IndexPair, 8> InterferenceRanges;
- InterferenceRanges.resize(LiveBlocks.size());
- for (const unsigned *AI = TRI->getOverlaps(PhysReg); *AI; ++AI) {
- if (!query(VirtReg, *AI).checkInterference())
+ // 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;
- LiveIntervalUnion::SegmentIter IntI =
- PhysReg2LiveUnion[*AI].find(VirtReg.beginIndex());
- if (!IntI.valid())
- continue;
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- BlockInfo &BI = LiveBlocks[i];
- if (!BI.Uses)
- continue;
- IndexPair &IP = InterferenceRanges[i];
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
- // Skip interference-free blocks.
- if (IntI.start() >= Stop)
+ }
+
+ if (IntvIn && IntvOut)
+ SE->splitLiveThroughBlock(Number, IntvIn, IntfIn, IntvOut, IntfOut);
+ else if (IntvIn)
+ SE->splitRegInBlock(BI, IntvIn, IntfIn);
+ else
+ SE->splitRegOutBlock(BI, IntvOut, IntfOut);
+ }
+
+ // 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);
- // First interference in block.
- if (BI.LiveIn) {
- IntI.advanceTo(Start);
- if (!IntI.valid())
- break;
- if (!IP.first.isValid() || IntI.start() < IP.first)
- IP.first = IntI.start();
+ unsigned IntvIn = 0, IntvOut = 0;
+ SlotIndex IntfIn, IntfOut;
+
+ 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();
}
- // Last interference in block.
- if (BI.LiveOut) {
- IntI.advanceTo(Stop);
- if (!IntI.valid() || IntI.start() >= Stop)
- --IntI;
- if (!IP.second.isValid() || IntI.stop() > IP.second)
- IP.second = IntI.stop();
+ 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);
}
}
- SmallVector<LiveInterval*, 4> SpillRegs;
- LiveRangeEdit LREdit(VirtReg, NewVRegs, SpillRegs);
- SplitEditor SE(*SA, *LIS, *VRM, *DomTree, LREdit);
+ ++NumGlobalSplits;
- // Create the main cross-block interval.
- SE.openIntv();
+ SmallVector<unsigned, 8> IntvMap;
+ SE->finish(&IntvMap);
+ DebugVars->splitRegister(Reg, LREdit.regs(), *LIS);
- // First add all defs that are live out of a block.
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- BlockInfo &BI = LiveBlocks[i];
- bool RegIn = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
- bool RegOut = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
+ ExtraRegInfo.resize(MRI->getNumVirtRegs());
+ unsigned OrigBlocks = SA->getNumLiveBlocks();
- // Should the register be live out?
- if (!BI.LiveOut || !RegOut)
- continue;
+ // Sort out the new intervals created by splitting. We get four kinds:
+ // - Remainder intervals should not be split again.
+ // - Candidate intervals can be assigned to Cand.PhysReg.
+ // - Block-local splits are candidates for local splitting.
+ // - DCE leftovers should go back on the queue.
+ for (unsigned i = 0, e = LREdit.size(); i != e; ++i) {
+ LiveInterval &Reg = LIS->getInterval(LREdit.get(i));
- IndexPair &IP = InterferenceRanges[i];
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
-
- DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " -> EB#"
- << Bundles->getBundle(BI.MBB->getNumber(), 1));
-
- // Check interference leaving the block.
- if (!IP.second.isValid() || IP.second < Start) {
- // Block is interference-free.
- DEBUG(dbgs() << ", no interference");
- if (!BI.Uses) {
- assert(BI.LiveThrough && "No uses, but not live through block?");
- // Block is live-through without interference.
- DEBUG(dbgs() << ", no uses"
- << (RegIn ? ", live-through.\n" : ", stack in.\n"));
- if (!RegIn)
- SE.enterIntvAtEnd(*BI.MBB);
- continue;
- }
- if (!BI.LiveThrough) {
- DEBUG(dbgs() << ", not live-through.\n");
- SE.useIntv(SE.enterIntvBefore(BI.Def), Stop);
- continue;
- }
- if (!RegIn) {
- // Block is live-through, but entry bundle is on the stack.
- // Reload just before the first use.
- DEBUG(dbgs() << ", not live-in, enter before first use.\n");
- SE.useIntv(SE.enterIntvBefore(BI.FirstUse), Stop);
- continue;
- }
- DEBUG(dbgs() << ", live-through.\n");
+ // Ignore old intervals from DCE.
+ if (getStage(Reg) != RS_New)
continue;
- }
- // Block has interference.
- DEBUG(dbgs() << ", interference to " << IP.second);
- if (!BI.Uses) {
- // No uses in block, avoid interference by reloading as late as possible.
- DEBUG(dbgs() << ", no uses.\n");
- SE.enterIntvAtEnd(*BI.MBB);
+ // Remainder interval. Don't try splitting again, spill if it doesn't
+ // allocate.
+ if (IntvMap[i] == 0) {
+ setStage(Reg, RS_Spill);
continue;
}
- if (IP.second < BI.LastUse) {
- // There are interference-free uses at the end of the block.
- // Find the first use that can get the live-out register.
- SmallVectorImpl<SlotIndex>::const_iterator UI =
- std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(), IP.second);
- assert(UI != SA->UseSlots.end() && "Couldn't find last use");
- SlotIndex Use = *UI;
- DEBUG(dbgs() << ", free use at " << Use << ".\n");
- assert(Use <= BI.LastUse && "Couldn't find last use");
- SE.useIntv(SE.enterIntvBefore(Use), Stop);
+
+ // Global intervals. Allow repeated splitting as long as the number of live
+ // blocks is strictly decreasing.
+ 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_Split2);
+ }
continue;
}
- // Interference is after the last use.
- DEBUG(dbgs() << " after last use.\n");
- SE.enterIntvAtEnd(*BI.MBB);
+ // Other intervals are treated as new. This includes local intervals created
+ // for blocks with multiple uses, and anything created by DCE.
}
- // Now all defs leading to live bundles are handled, do everything else.
- for (unsigned i = 0, e = LiveBlocks.size(); i != e; ++i) {
- BlockInfo &BI = LiveBlocks[i];
- bool RegIn = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
- bool RegOut = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
+ if (VerifyEnabled)
+ MF->verify(this, "After splitting live range around region");
+}
- // Is the register live-in?
- if (!BI.LiveIn || !RegIn)
- continue;
+unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
+ SmallVectorImpl<unsigned> &NewVRegs) {
+ unsigned NumCands = 0;
+ unsigned BestCand = NoCand;
+ BlockFrequency 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 = BlockFrequency::getMaxFrequency();
+ } 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 = calcSpillCost();
+ DEBUG(dbgs() << "Cost of isolating all blocks = ";
+ MBFI->printBlockFreq(dbgs(), BestCost) << '\n');
+ }
- // We have an incoming register. Check for interference.
- IndexPair &IP = InterferenceRanges[i];
- SlotIndex Start, Stop;
- tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
-
- DEBUG(dbgs() << "EB#" << Bundles->getBundle(BI.MBB->getNumber(), 0)
- << " -> BB#" << BI.MBB->getNumber());
-
- // Check interference entering the block.
- if (!IP.first.isValid() || IP.first > Stop) {
- // Block is interference-free.
- DEBUG(dbgs() << ", no interference");
- if (!BI.Uses) {
- assert(BI.LiveThrough && "No uses, but not live through block?");
- // Block is live-through without interference.
- if (RegOut) {
- DEBUG(dbgs() << ", no uses, live-through.\n");
- SE.useIntv(Start, Stop);
- } else {
- DEBUG(dbgs() << ", no uses, stack-out.\n");
- SE.leaveIntvAtTop(*BI.MBB);
- }
- continue;
- }
- if (!BI.LiveThrough) {
- DEBUG(dbgs() << ", killed in block.\n");
- SE.useIntv(Start, SE.leaveIntvAfter(BI.Kill));
- continue;
- }
- if (!RegOut) {
- // Block is live-through, but exit bundle is on the stack.
- // Spill immediately after the last use.
- DEBUG(dbgs() << ", uses, stack-out.\n");
- SE.useIntv(Start, SE.leaveIntvAfter(BI.LastUse));
- continue;
+ Order.rewind();
+ 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;
}
- // Register is live-through.
- DEBUG(dbgs() << ", uses, live-through.\n");
- SE.useIntv(Start, Stop);
- continue;
+ --NumCands;
+ GlobalCand[Worst] = GlobalCand[NumCands];
+ if (BestCand == NumCands)
+ BestCand = Worst;
}
- // Block has interference.
- DEBUG(dbgs() << ", interference from " << IP.first);
- if (!BI.Uses) {
- // No uses in block, avoid interference by spilling as soon as possible.
- DEBUG(dbgs() << ", no uses.\n");
- SE.leaveIntvAtTop(*BI.MBB);
+ if (GlobalCand.size() <= NumCands)
+ GlobalCand.resize(NumCands+1);
+ GlobalSplitCandidate &Cand = GlobalCand[NumCands];
+ Cand.reset(IntfCache, PhysReg);
+
+ SpillPlacer->prepare(Cand.LiveBundles);
+ BlockFrequency Cost;
+ if (!addSplitConstraints(Cand.Intf, Cost)) {
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tno positive bundles\n");
+ continue;
+ }
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tstatic = ";
+ MBFI->printBlockFreq(dbgs(), Cost));
+ if (Cost >= BestCost) {
+ DEBUG({
+ if (BestCand == NoCand)
+ dbgs() << " worse than no bundles\n";
+ else
+ dbgs() << " worse than "
+ << PrintReg(GlobalCand[BestCand].PhysReg, TRI) << '\n';
+ });
continue;
}
- if (IP.first > BI.FirstUse) {
- // There are interference-free uses at the beginning of the block.
- // Find the last use that can get the register.
- SmallVectorImpl<SlotIndex>::const_iterator UI =
- std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(), IP.first);
- assert(UI != SA->UseSlots.begin() && "Couldn't find first use");
- SlotIndex Use = (--UI)->getBoundaryIndex();
- DEBUG(dbgs() << ", free use at " << *UI << ".\n");
- assert(Use >= BI.FirstUse && Use < IP.first);
- SE.useIntv(Start, SE.leaveIntvAfter(Use));
+ growRegion(Cand);
+
+ SpillPlacer->finish();
+
+ // No live bundles, defer to splitSingleBlocks().
+ if (!Cand.LiveBundles.any()) {
+ DEBUG(dbgs() << " no bundles.\n");
continue;
}
- // Interference is before the first use.
- DEBUG(dbgs() << " before first use.\n");
- SE.leaveIntvAtTop(*BI.MBB);
+ Cost += calcGlobalSplitCost(Cand);
+ DEBUG({
+ dbgs() << ", total = "; MBFI->printBlockFreq(dbgs(), Cost)
+ << " with bundles";
+ for (int i = Cand.LiveBundles.find_first(); i>=0;
+ i = Cand.LiveBundles.find_next(i))
+ dbgs() << " EB#" << i;
+ dbgs() << ".\n";
+ });
+ if (Cost < BestCost) {
+ BestCand = NumCands;
+ BestCost = Cost;
+ }
+ ++NumCands;
+ }
+
+ // No solutions found, fall back to single block splitting.
+ if (!HasCompact && BestCand == NoCand)
+ return 0;
+
+ // Prepare split editor.
+ LiveRangeEdit LREdit(&VirtReg, NewVRegs, *MF, *LIS, VRM, 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<unsigned> &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, *MF, *LIS, VRM, 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;
- SE.closeIntv();
+ // We did split for some blocks.
+ SmallVector<unsigned, 8> IntvMap;
+ SE->finish(&IntvMap);
- // FIXME: Should we be more aggressive about splitting the stack region into
- // per-block segments? The current approach allows the stack region to
- // separate into connected components. Some components may be allocatable.
- SE.finish();
+ // Tell LiveDebugVariables about the new ranges.
+ DebugVars->splitRegister(Reg, LREdit.regs(), *LIS);
+
+ 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 = LIS->getInterval(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 region");
+ MF->verify(this, "After splitting live range around basic blocks");
+ return 0;
}
-unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
- SmallVectorImpl<LiveInterval*> &NewVRegs) {
- calcLiveBlockInfo(VirtReg);
- BitVector LiveBundles, BestBundles;
- float BestCost = 0;
- unsigned BestReg = 0;
+
+//===----------------------------------------------------------------------===//
+// Per-Instruction Splitting
+//===----------------------------------------------------------------------===//
+
+/// Get the number of allocatable registers that match the constraints of \p Reg
+/// on \p MI and that are also in \p SuperRC.
+static unsigned getNumAllocatableRegsForConstraints(
+ const MachineInstr *MI, unsigned Reg, const TargetRegisterClass *SuperRC,
+ const TargetInstrInfo *TII, const TargetRegisterInfo *TRI,
+ const RegisterClassInfo &RCI) {
+ assert(SuperRC && "Invalid register class");
+
+ const TargetRegisterClass *ConstrainedRC =
+ MI->getRegClassConstraintEffectForVReg(Reg, SuperRC, TII, TRI,
+ /* ExploreBundle */ true);
+ if (!ConstrainedRC)
+ return 0;
+ return RCI.getNumAllocatableRegs(ConstrainedRC);
+}
+
+/// tryInstructionSplit - Split a live range around individual instructions.
+/// This is normally not worthwhile since the spiller is doing essentially the
+/// same thing. However, when the live range is in a constrained register
+/// class, it may help to insert copies such that parts of the live range can
+/// be moved to a larger register class.
+///
+/// This is similar to spilling to a larger register class.
+unsigned
+RAGreedy::tryInstructionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
+ SmallVectorImpl<unsigned> &NewVRegs) {
+ const TargetRegisterClass *CurRC = MRI->getRegClass(VirtReg.reg);
+ // There is no point to this if there are no larger sub-classes.
+ if (!RegClassInfo.isProperSubClass(CurRC))
+ return 0;
+
+ // Always enable split spill mode, since we're effectively spilling to a
+ // register.
+ LiveRangeEdit LREdit(&VirtReg, NewVRegs, *MF, *LIS, VRM, this);
+ SE->reset(LREdit, SplitEditor::SM_Size);
+
+ ArrayRef<SlotIndex> Uses = SA->getUseSlots();
+ if (Uses.size() <= 1)
+ return 0;
+
+ DEBUG(dbgs() << "Split around " << Uses.size() << " individual instrs.\n");
+
+ const TargetRegisterClass *SuperRC = TRI->getLargestLegalSuperClass(CurRC);
+ unsigned SuperRCNumAllocatableRegs = RCI.getNumAllocatableRegs(SuperRC);
+ // Split around every non-copy instruction if this split will relax
+ // the constraints on the virtual register.
+ // Otherwise, splitting just inserts uncoalescable copies that do not help
+ // the allocation.
+ for (unsigned i = 0; i != Uses.size(); ++i) {
+ if (const MachineInstr *MI = Indexes->getInstructionFromIndex(Uses[i]))
+ if (MI->isFullCopy() ||
+ SuperRCNumAllocatableRegs ==
+ getNumAllocatableRegsForConstraints(MI, VirtReg.reg, SuperRC, TII,
+ TRI, RCI)) {
+ DEBUG(dbgs() << " skip:\t" << Uses[i] << '\t' << *MI);
+ continue;
+ }
+ SE->openIntv();
+ SlotIndex SegStart = SE->enterIntvBefore(Uses[i]);
+ SlotIndex SegStop = SE->leaveIntvAfter(Uses[i]);
+ SE->useIntv(SegStart, SegStop);
+ }
+
+ if (LREdit.empty()) {
+ DEBUG(dbgs() << "All uses were copies.\n");
+ return 0;
+ }
+
+ SmallVector<unsigned, 8> IntvMap;
+ SE->finish(&IntvMap);
+ DebugVars->splitRegister(VirtReg.reg, LREdit.regs(), *LIS);
+ ExtraRegInfo.resize(MRI->getNumVirtRegs());
+
+ // Assign all new registers to RS_Spill. This was the last chance.
+ setStage(LREdit.begin(), LREdit.end(), RS_Spill);
+ return 0;
+}
+
+
+//===----------------------------------------------------------------------===//
+// Local Splitting
+//===----------------------------------------------------------------------===//
+
+
+/// calcGapWeights - Compute the maximum spill weight that needs to be evicted
+/// in order to use PhysReg between two entries in SA->UseSlots.
+///
+/// GapWeight[i] represents the gap between UseSlots[i] and UseSlots[i+1].
+///
+void RAGreedy::calcGapWeights(unsigned PhysReg,
+ SmallVectorImpl<float> &GapWeight) {
+ assert(SA->getUseBlocks().size() == 1 && "Not a local interval");
+ const SplitAnalysis::BlockInfo &BI = SA->getUseBlocks().front();
+ ArrayRef<SlotIndex> Uses = SA->getUseSlots();
+ const unsigned NumGaps = Uses.size()-1;
+
+ // Start and end points for the interference check.
+ SlotIndex StartIdx =
+ BI.LiveIn ? BI.FirstInstr.getBaseIndex() : BI.FirstInstr;
+ SlotIndex StopIdx =
+ BI.LiveOut ? BI.LastInstr.getBoundaryIndex() : BI.LastInstr;
+
+ GapWeight.assign(NumGaps, 0.0f);
+
+ // Add interference from each overlapping register.
+ for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+ if (!Matrix->query(const_cast<LiveInterval&>(SA->getParent()), *Units)
+ .checkInterference())
+ continue;
+
+ // 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 =
+ Matrix->getLiveUnions()[*Units] .find(StartIdx);
+ for (unsigned Gap = 0; IntI.valid() && IntI.start() < StopIdx; ++IntI) {
+ // Skip the gaps before IntI.
+ while (Uses[Gap+1].getBoundaryIndex() < IntI.start())
+ if (++Gap == NumGaps)
+ break;
+ if (Gap == NumGaps)
+ break;
+
+ // Update the gaps covered by IntI.
+ const float weight = IntI.value()->weight;
+ for (; Gap != NumGaps; ++Gap) {
+ GapWeight[Gap] = std::max(GapWeight[Gap], weight);
+ if (Uses[Gap+1].getBaseIndex() >= IntI.stop())
+ break;
+ }
+ if (Gap == NumGaps)
+ break;
+ }
+ }
+
+ // Add fixed interference.
+ for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+ const LiveRange &LR = LIS->getRegUnit(*Units);
+ LiveRange::const_iterator I = LR.find(StartIdx);
+ LiveRange::const_iterator E = LR.end();
+
+ // Same loop as above. Mark any overlapped gaps as HUGE_VALF.
+ for (unsigned Gap = 0; I != E && I->start < StopIdx; ++I) {
+ while (Uses[Gap+1].getBoundaryIndex() < I->start)
+ if (++Gap == NumGaps)
+ break;
+ if (Gap == NumGaps)
+ break;
+
+ for (; Gap != NumGaps; ++Gap) {
+ GapWeight[Gap] = llvm::huge_valf;
+ if (Uses[Gap+1].getBaseIndex() >= I->end)
+ break;
+ }
+ if (Gap == NumGaps)
+ break;
+ }
+ }
+}
+
+/// tryLocalSplit - Try to split VirtReg into smaller intervals inside its only
+/// basic block.
+///
+unsigned RAGreedy::tryLocalSplit(LiveInterval &VirtReg, AllocationOrder &Order,
+ SmallVectorImpl<unsigned> &NewVRegs) {
+ assert(SA->getUseBlocks().size() == 1 && "Not a local interval");
+ const SplitAnalysis::BlockInfo &BI = SA->getUseBlocks().front();
+
+ // Note that it is possible to have an interval that is live-in or live-out
+ // 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 FirstInstr to LastInstr. We should
+ // make sure that we don't do anything illegal to such an interval, though.
+
+ 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() << ' ' << Uses[i];
+ dbgs() << '\n';
+ });
+
+ // If VirtReg is live across any register mask operands, compute a list of
+ // gaps with register masks.
+ SmallVector<unsigned, 8> RegMaskGaps;
+ if (Matrix->checkRegMaskInterference(VirtReg)) {
+ // Get regmask slots for the whole block.
+ ArrayRef<SlotIndex> RMS = LIS->getRegMaskSlotsInBlock(BI.MBB->getNumber());
+ DEBUG(dbgs() << RMS.size() << " regmasks in block:");
+ // Constrain to VirtReg's live range.
+ unsigned ri = std::lower_bound(RMS.begin(), RMS.end(),
+ Uses.front().getRegSlot()) - RMS.begin();
+ unsigned re = RMS.size();
+ for (unsigned i = 0; i != NumGaps && ri != re; ++i) {
+ // Look for Uses[i] <= RMS <= Uses[i+1].
+ assert(!SlotIndex::isEarlierInstr(RMS[ri], Uses[i]));
+ if (SlotIndex::isEarlierInstr(Uses[i+1], RMS[ri]))
+ continue;
+ // Skip a regmask on the same instruction as the last use. It doesn't
+ // overlap the live range.
+ if (SlotIndex::isSameInstr(Uses[i+1], RMS[ri]) && i+1 == NumGaps)
+ break;
+ DEBUG(dbgs() << ' ' << RMS[ri] << ':' << Uses[i] << '-' << Uses[i+1]);
+ RegMaskGaps.push_back(i);
+ // Advance ri to the next gap. A regmask on one of the uses counts in
+ // both gaps.
+ while (ri != re && SlotIndex::isEarlierInstr(RMS[ri], Uses[i+1]))
+ ++ri;
+ }
+ DEBUG(dbgs() << '\n');
+ }
+
+ // Since we allow local split results to be split again, there is a risk of
+ // creating infinite loops. It is tempting to require that the new live
+ // ranges have less instructions than the original. That would guarantee
+ // convergence, but it is too strict. A live range with 3 instructions can be
+ // split 2+3 (including the COPY), and we want to allow that.
+ //
+ // Instead we use these rules:
+ //
+ // 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_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_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_Split2;
+
+ // Best split candidate.
+ unsigned BestBefore = NumGaps;
+ unsigned BestAfter = 0;
+ float BestDiff = 0;
+
+ const float blockFreq =
+ SpillPlacer->getBlockFrequency(BI.MBB->getNumber()).getFrequency() *
+ (1.0f / MBFI->getEntryFreq());
+ SmallVector<float, 8> GapWeight;
+
Order.rewind();
while (unsigned PhysReg = Order.next()) {
- float Cost = calcInterferenceInfo(VirtReg, PhysReg);
- if (BestReg && Cost >= BestCost)
- continue;
+ // Keep track of the largest spill weight that would need to be evicted in
+ // order to make use of PhysReg between UseSlots[i] and UseSlots[i+1].
+ calcGapWeights(PhysReg, GapWeight);
- SpillPlacer->placeSpills(SpillConstraints, LiveBundles);
- // No live bundles, defer to splitSingleBlocks().
- if (!LiveBundles.any())
- continue;
+ // Remove any gaps with regmask clobbers.
+ if (Matrix->checkRegMaskInterference(VirtReg, PhysReg))
+ for (unsigned i = 0, e = RegMaskGaps.size(); i != e; ++i)
+ GapWeight[RegMaskGaps[i]] = llvm::huge_valf;
- Cost += calcGlobalSplitCost(LiveBundles);
- if (!BestReg || Cost < BestCost) {
- BestReg = PhysReg;
- BestCost = Cost;
- BestBundles.swap(LiveBundles);
+ // Try to find the best sequence of gaps to close.
+ // The new spill weight must be larger than any gap interference.
+
+ // We will split before Uses[SplitBefore] and after Uses[SplitAfter].
+ unsigned SplitBefore = 0, SplitAfter = 1;
+
+ // MaxGap should always be max(GapWeight[SplitBefore..SplitAfter-1]).
+ // It is the spill weight that needs to be evicted.
+ float MaxGap = GapWeight[0];
+
+ for (;;) {
+ // Live before/after split?
+ const bool LiveBefore = SplitBefore != 0 || BI.LiveIn;
+ const bool LiveAfter = SplitAfter != NumGaps || BI.LiveOut;
+
+ DEBUG(dbgs() << PrintReg(PhysReg, TRI) << ' '
+ << Uses[SplitBefore] << '-' << Uses[SplitAfter]
+ << " i=" << MaxGap);
+
+ // Stop before the interval gets so big we wouldn't be making progress.
+ if (!LiveBefore && !LiveAfter) {
+ DEBUG(dbgs() << " all\n");
+ break;
+ }
+ // Should the interval be extended or shrunk?
+ bool Shrink = true;
+
+ // How many gaps would the new range have?
+ unsigned NewGaps = LiveBefore + SplitAfter - SplitBefore + LiveAfter;
+
+ // Legally, without causing looping?
+ bool Legal = !ProgressRequired || NewGaps < NumGaps;
+
+ if (Legal && MaxGap < llvm::huge_valf) {
+ // Estimate the new spill weight. Each instruction reads or writes the
+ // register. Conservatively assume there are no read-modify-write
+ // instructions.
+ //
+ // Try to guess the size of the new interval.
+ const float EstWeight = normalizeSpillWeight(blockFreq * (NewGaps + 1),
+ Uses[SplitBefore].distance(Uses[SplitAfter]) +
+ (LiveBefore + LiveAfter)*SlotIndex::InstrDist);
+ // Would this split be possible to allocate?
+ // Never allocate all gaps, we wouldn't be making progress.
+ DEBUG(dbgs() << " w=" << EstWeight);
+ if (EstWeight * Hysteresis >= MaxGap) {
+ Shrink = false;
+ float Diff = EstWeight - MaxGap;
+ if (Diff > BestDiff) {
+ DEBUG(dbgs() << " (best)");
+ BestDiff = Hysteresis * Diff;
+ BestBefore = SplitBefore;
+ BestAfter = SplitAfter;
+ }
+ }
+ }
+
+ // Try to shrink.
+ if (Shrink) {
+ if (++SplitBefore < SplitAfter) {
+ DEBUG(dbgs() << " shrink\n");
+ // Recompute the max when necessary.
+ if (GapWeight[SplitBefore - 1] >= MaxGap) {
+ MaxGap = GapWeight[SplitBefore];
+ for (unsigned i = SplitBefore + 1; i != SplitAfter; ++i)
+ MaxGap = std::max(MaxGap, GapWeight[i]);
+ }
+ continue;
+ }
+ MaxGap = 0;
+ }
+
+ // Try to extend the interval.
+ if (SplitAfter >= NumGaps) {
+ DEBUG(dbgs() << " end\n");
+ break;
+ }
+
+ DEBUG(dbgs() << " extend\n");
+ MaxGap = std::max(MaxGap, GapWeight[SplitAfter++]);
}
}
- if (!BestReg)
+ // Didn't find any candidates?
+ if (BestBefore == NumGaps)
return 0;
- splitAroundRegion(VirtReg, BestReg, BestBundles, NewVRegs);
+ DEBUG(dbgs() << "Best local split range: " << Uses[BestBefore]
+ << '-' << Uses[BestAfter] << ", " << BestDiff
+ << ", " << (BestAfter - BestBefore + 1) << " instrs\n");
+
+ LiveRangeEdit LREdit(&VirtReg, NewVRegs, *MF, *LIS, VRM, this);
+ SE->reset(LREdit);
+
+ SE->openIntv();
+ SlotIndex SegStart = SE->enterIntvBefore(Uses[BestBefore]);
+ SlotIndex SegStop = SE->leaveIntvAfter(Uses[BestAfter]);
+ SE->useIntv(SegStart, SegStop);
+ SmallVector<unsigned, 8> IntvMap;
+ SE->finish(&IntvMap);
+ DebugVars->splitRegister(VirtReg.reg, LREdit.regs(), *LIS);
+
+ // If the new range has the same number of instructions as before, mark it as
+ // 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;
+ unsigned NewGaps = LiveBefore + BestAfter - BestBefore + LiveAfter;
+ if (NewGaps >= NumGaps) {
+ DEBUG(dbgs() << "Tagging non-progress ranges: ");
+ 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(LIS->getInterval(LREdit.get(i)), RS_Split2);
+ DEBUG(dbgs() << PrintReg(LREdit.get(i)));
+ }
+ DEBUG(dbgs() << '\n');
+ }
+ ++NumLocalSplits;
+
return 0;
}
-
//===----------------------------------------------------------------------===//
// Live Range Splitting
//===----------------------------------------------------------------------===//
/// assignable.
/// @return Physreg when VirtReg may be assigned and/or new NewVRegs.
unsigned RAGreedy::trySplit(LiveInterval &VirtReg, AllocationOrder &Order,
- SmallVectorImpl<LiveInterval*>&NewVRegs) {
- NamedRegionTimer T("Splitter", TimerGroupName, TimePassesIsEnabled);
- SA->analyze(&VirtReg);
-
- // Don't attempt splitting on local intervals for now. TBD.
- if (LIS->intervalIsInOneMBB(VirtReg))
+ SmallVectorImpl<unsigned>&NewVRegs) {
+ // Ranges must be Split2 or less.
+ if (getStage(VirtReg) >= RS_Spill)
return 0;
- // First try to split around a region spanning multiple blocks.
- unsigned PhysReg = tryRegionSplit(VirtReg, Order, NewVRegs);
- if (PhysReg || !NewVRegs.empty())
- return PhysReg;
+ // Local intervals are handled separately.
+ if (LIS->intervalIsInOneMBB(VirtReg)) {
+ NamedRegionTimer T("Local Splitting", TimerGroupName, TimePassesIsEnabled);
+ SA->analyze(&VirtReg);
+ unsigned PhysReg = tryLocalSplit(VirtReg, Order, NewVRegs);
+ if (PhysReg || !NewVRegs.empty())
+ return PhysReg;
+ return tryInstructionSplit(VirtReg, Order, NewVRegs);
+ }
+
+ NamedRegionTimer T("Global Splitting", TimerGroupName, TimePassesIsEnabled);
- // Then isolate blocks with multiple uses.
- SplitAnalysis::BlockPtrSet Blocks;
- if (SA->getMultiUseBlocks(Blocks)) {
- SmallVector<LiveInterval*, 4> SpillRegs;
- LiveRangeEdit LREdit(VirtReg, NewVRegs, SpillRegs);
- SplitEditor(*SA, *LIS, *VRM, *DomTree, LREdit).splitSingleBlocks(Blocks);
- if (VerifyEnabled)
- MF->verify(this, "After splitting live range around basic blocks");
+ SA->analyze(&VirtReg);
+
+ // FIXME: SplitAnalysis may repair broken live ranges coming from the
+ // coalescer. That may cause the range to become allocatable which means that
+ // tryRegionSplit won't be making progress. This check should be replaced with
+ // an assertion when the coalescer is fixed.
+ if (SA->didRepairRange()) {
+ // VirtReg has changed, so all cached queries are invalid.
+ Matrix->invalidateVirtRegs();
+ if (unsigned PhysReg = tryAssign(VirtReg, Order, NewVRegs))
+ return PhysReg;
}
- // Don't assign any physregs.
- return 0;
-}
+ // 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;
+ }
+ // Then isolate blocks.
+ return tryBlockSplit(VirtReg, Order, NewVRegs);
+}
//===----------------------------------------------------------------------===//
-// Spilling
+// Last Chance Recoloring
//===----------------------------------------------------------------------===//
-/// calcInterferenceWeight - Calculate the combined spill weight of
-/// interferences when assigning VirtReg to PhysReg.
-float RAGreedy::calcInterferenceWeight(LiveInterval &VirtReg, unsigned PhysReg){
- float Sum = 0;
- for (const unsigned *AI = TRI->getOverlaps(PhysReg); *AI; ++AI) {
- LiveIntervalUnion::Query &Q = query(VirtReg, *AI);
- Q.collectInterferingVRegs();
- if (Q.seenUnspillableVReg())
- return HUGE_VALF;
- for (unsigned i = 0, e = Q.interferingVRegs().size(); i != e; ++i)
- Sum += Q.interferingVRegs()[i]->weight;
- }
- return Sum;
-}
-
-/// trySpillInterferences - Try to spill interfering registers instead of the
-/// current one. Only do it if the accumulated spill weight is smaller than the
-/// current spill weight.
-unsigned RAGreedy::trySpillInterferences(LiveInterval &VirtReg,
- AllocationOrder &Order,
- SmallVectorImpl<LiveInterval*> &NewVRegs) {
- NamedRegionTimer T("Spill Interference", TimerGroupName, TimePassesIsEnabled);
- unsigned BestPhys = 0;
- float BestWeight = 0;
+/// mayRecolorAllInterferences - Check if the virtual registers that
+/// interfere with \p VirtReg on \p PhysReg (or one of its aliases) may be
+/// recolored to free \p PhysReg.
+/// When true is returned, \p RecoloringCandidates has been augmented with all
+/// the live intervals that need to be recolored in order to free \p PhysReg
+/// for \p VirtReg.
+/// \p FixedRegisters contains all the virtual registers that cannot be
+/// recolored.
+bool
+RAGreedy::mayRecolorAllInterferences(unsigned PhysReg, LiveInterval &VirtReg,
+ SmallLISet &RecoloringCandidates,
+ const SmallVirtRegSet &FixedRegisters) {
+ const TargetRegisterClass *CurRC = MRI->getRegClass(VirtReg.reg);
+
+ for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+ LiveIntervalUnion::Query &Q = Matrix->query(VirtReg, *Units);
+ // If there is LastChanceRecoloringMaxInterference or more interferences,
+ // chances are one would not be recolorable.
+ if (Q.collectInterferingVRegs(LastChanceRecoloringMaxInterference) >=
+ LastChanceRecoloringMaxInterference) {
+ DEBUG(dbgs() << "Early abort: too many interferences.\n");
+ return false;
+ }
+ for (unsigned i = Q.interferingVRegs().size(); i; --i) {
+ LiveInterval *Intf = Q.interferingVRegs()[i - 1];
+ // If Intf is done and sit on the same register class as VirtReg,
+ // it would not be recolorable as it is in the same state as VirtReg.
+ if ((getStage(*Intf) == RS_Done &&
+ MRI->getRegClass(Intf->reg) == CurRC) ||
+ FixedRegisters.count(Intf->reg)) {
+ DEBUG(dbgs() << "Early abort: the inteference is not recolorable.\n");
+ return false;
+ }
+ RecoloringCandidates.insert(Intf);
+ }
+ }
+ return true;
+}
+
+/// tryLastChanceRecoloring - Try to assign a color to \p VirtReg by recoloring
+/// its interferences.
+/// Last chance recoloring chooses a color for \p VirtReg and recolors every
+/// virtual register that was using it. The recoloring process may recursively
+/// use the last chance recoloring. Therefore, when a virtual register has been
+/// assigned a color by this mechanism, it is marked as Fixed, i.e., it cannot
+/// be last-chance-recolored again during this recoloring "session".
+/// E.g.,
+/// Let
+/// vA can use {R1, R2 }
+/// vB can use { R2, R3}
+/// vC can use {R1 }
+/// Where vA, vB, and vC cannot be split anymore (they are reloads for
+/// instance) and they all interfere.
+///
+/// vA is assigned R1
+/// vB is assigned R2
+/// vC tries to evict vA but vA is already done.
+/// Regular register allocation fails.
+///
+/// Last chance recoloring kicks in:
+/// vC does as if vA was evicted => vC uses R1.
+/// vC is marked as fixed.
+/// vA needs to find a color.
+/// None are available.
+/// vA cannot evict vC: vC is a fixed virtual register now.
+/// vA does as if vB was evicted => vA uses R2.
+/// vB needs to find a color.
+/// R3 is available.
+/// Recoloring => vC = R1, vA = R2, vB = R3
+///
+/// \p Order defines the prefered allocation order for \p VirtReg.
+/// \p NewRegs will contain any new virtual register that have been created
+/// (split, spill) during the process and that must be assigned.
+/// \p FixedRegisters contains all the virtual registers that cannot be
+/// recolored.
+/// \p Depth gives the current depth of the last chance recoloring.
+/// \return a physical register that can be used for VirtReg or ~0u if none
+/// exists.
+unsigned RAGreedy::tryLastChanceRecoloring(LiveInterval &VirtReg,
+ AllocationOrder &Order,
+ SmallVectorImpl<unsigned> &NewVRegs,
+ SmallVirtRegSet &FixedRegisters,
+ unsigned Depth) {
+ DEBUG(dbgs() << "Try last chance recoloring for " << VirtReg << '\n');
+ // Ranges must be Done.
+ assert(getStage(VirtReg) >= RS_Done &&
+ "Last chance recoloring should really be last chance");
+ // Set the max depth to LastChanceRecoloringMaxDepth.
+ // We may want to reconsider that if we end up with a too large search space
+ // for target with hundreds of registers.
+ // Indeed, in that case we may want to cut the search space earlier.
+ if (Depth >= LastChanceRecoloringMaxDepth) {
+ DEBUG(dbgs() << "Abort because max depth has been reached.\n");
+ return ~0u;
+ }
+
+ // Set of Live intervals that will need to be recolored.
+ SmallLISet RecoloringCandidates;
+ // Record the original mapping virtual register to physical register in case
+ // the recoloring fails.
+ DenseMap<unsigned, unsigned> VirtRegToPhysReg;
+ // Mark VirtReg as fixed, i.e., it will not be recolored pass this point in
+ // this recoloring "session".
+ FixedRegisters.insert(VirtReg.reg);
Order.rewind();
while (unsigned PhysReg = Order.next()) {
- float Weight = calcInterferenceWeight(VirtReg, PhysReg);
- if (Weight == HUGE_VALF || Weight >= VirtReg.weight)
+ DEBUG(dbgs() << "Try to assign: " << VirtReg << " to "
+ << PrintReg(PhysReg, TRI) << '\n');
+ RecoloringCandidates.clear();
+ VirtRegToPhysReg.clear();
+
+ // It is only possible to recolor virtual register interference.
+ if (Matrix->checkInterference(VirtReg, PhysReg) >
+ LiveRegMatrix::IK_VirtReg) {
+ DEBUG(dbgs() << "Some inteferences are not with virtual registers.\n");
+
continue;
- if (!BestPhys || Weight < BestWeight)
- BestPhys = PhysReg, BestWeight = Weight;
- }
+ }
- // No candidates found.
- if (!BestPhys)
- return 0;
+ // Early give up on this PhysReg if it is obvious we cannot recolor all
+ // the interferences.
+ if (!mayRecolorAllInterferences(PhysReg, VirtReg, RecoloringCandidates,
+ FixedRegisters)) {
+ DEBUG(dbgs() << "Some inteferences cannot be recolored.\n");
+ continue;
+ }
+
+ // RecoloringCandidates contains all the virtual registers that interfer
+ // with VirtReg on PhysReg (or one of its aliases).
+ // Enqueue them for recoloring and perform the actual recoloring.
+ PQueue RecoloringQueue;
+ for (SmallLISet::iterator It = RecoloringCandidates.begin(),
+ EndIt = RecoloringCandidates.end();
+ It != EndIt; ++It) {
+ unsigned ItVirtReg = (*It)->reg;
+ enqueue(RecoloringQueue, *It);
+ assert(VRM->hasPhys(ItVirtReg) &&
+ "Interferences are supposed to be with allocated vairables");
+
+ // Record the current allocation.
+ VirtRegToPhysReg[ItVirtReg] = VRM->getPhys(ItVirtReg);
+ // unset the related struct.
+ Matrix->unassign(**It);
+ }
- // Collect all interfering registers.
- SmallVector<LiveInterval*, 8> Spills;
- for (const unsigned *AI = TRI->getOverlaps(BestPhys); *AI; ++AI) {
- LiveIntervalUnion::Query &Q = query(VirtReg, *AI);
- Spills.append(Q.interferingVRegs().begin(), Q.interferingVRegs().end());
- for (unsigned i = 0, e = Q.interferingVRegs().size(); i != e; ++i) {
- LiveInterval *VReg = Q.interferingVRegs()[i];
- PhysReg2LiveUnion[*AI].extract(*VReg);
- VRM->clearVirt(VReg->reg);
+ // Do as if VirtReg was assigned to PhysReg so that the underlying
+ // recoloring has the right information about the interferes and
+ // available colors.
+ Matrix->assign(VirtReg, PhysReg);
+
+ // Save the current recoloring state.
+ // If we cannot recolor all the interferences, we will have to start again
+ // at this point for the next physical register.
+ SmallVirtRegSet SaveFixedRegisters(FixedRegisters);
+ if (tryRecoloringCandidates(RecoloringQueue, NewVRegs, FixedRegisters,
+ Depth)) {
+ // Do not mess up with the global assignment process.
+ // I.e., VirtReg must be unassigned.
+ Matrix->unassign(VirtReg);
+ return PhysReg;
+ }
+
+ DEBUG(dbgs() << "Fail to assign: " << VirtReg << " to "
+ << PrintReg(PhysReg, TRI) << '\n');
+
+ // The recoloring attempt failed, undo the changes.
+ FixedRegisters = SaveFixedRegisters;
+ Matrix->unassign(VirtReg);
+
+ for (SmallLISet::iterator It = RecoloringCandidates.begin(),
+ EndIt = RecoloringCandidates.end();
+ It != EndIt; ++It) {
+ unsigned ItVirtReg = (*It)->reg;
+ if (VRM->hasPhys(ItVirtReg))
+ Matrix->unassign(**It);
+ Matrix->assign(**It, VirtRegToPhysReg[ItVirtReg]);
}
}
- // Spill them all.
- DEBUG(dbgs() << "spilling " << Spills.size() << " interferences with weight "
- << BestWeight << '\n');
- for (unsigned i = 0, e = Spills.size(); i != e; ++i)
- spiller().spill(Spills[i], NewVRegs, Spills);
- return BestPhys;
+ // Last chance recoloring did not worked either, give up.
+ return ~0u;
}
+/// tryRecoloringCandidates - Try to assign a new color to every register
+/// in \RecoloringQueue.
+/// \p NewRegs will contain any new virtual register created during the
+/// recoloring process.
+/// \p FixedRegisters[in/out] contains all the registers that have been
+/// recolored.
+/// \return true if all virtual registers in RecoloringQueue were successfully
+/// recolored, false otherwise.
+bool RAGreedy::tryRecoloringCandidates(PQueue &RecoloringQueue,
+ SmallVectorImpl<unsigned> &NewVRegs,
+ SmallVirtRegSet &FixedRegisters,
+ unsigned Depth) {
+ while (!RecoloringQueue.empty()) {
+ LiveInterval *LI = dequeue(RecoloringQueue);
+ DEBUG(dbgs() << "Try to recolor: " << *LI << '\n');
+ unsigned PhysReg;
+ PhysReg = selectOrSplitImpl(*LI, NewVRegs, FixedRegisters, Depth + 1);
+ if (PhysReg == ~0u || !PhysReg)
+ return false;
+ DEBUG(dbgs() << "Recoloring of " << *LI
+ << " succeeded with: " << PrintReg(PhysReg, TRI) << '\n');
+ Matrix->assign(*LI, PhysReg);
+ FixedRegisters.insert(LI->reg);
+ }
+ return true;
+}
//===----------------------------------------------------------------------===//
// Main Entry Point
//===----------------------------------------------------------------------===//
unsigned RAGreedy::selectOrSplit(LiveInterval &VirtReg,
- SmallVectorImpl<LiveInterval*> &NewVRegs) {
- // First try assigning a free register.
- AllocationOrder Order(VirtReg.reg, *VRM, ReservedRegs);
- while (unsigned PhysReg = Order.next()) {
- if (!checkPhysRegInterference(VirtReg, PhysReg))
- return PhysReg;
- }
+ SmallVectorImpl<unsigned> &NewVRegs) {
+ SmallVirtRegSet FixedRegisters;
+ return selectOrSplitImpl(VirtReg, NewVRegs, FixedRegisters);
+}
- // Try to reassign interferences.
- if (unsigned PhysReg = tryReassign(VirtReg, Order))
+unsigned RAGreedy::selectOrSplitImpl(LiveInterval &VirtReg,
+ SmallVectorImpl<unsigned> &NewVRegs,
+ SmallVirtRegSet &FixedRegisters,
+ unsigned Depth) {
+ // First try assigning a free register.
+ AllocationOrder Order(VirtReg.reg, *VRM, RegClassInfo);
+ if (unsigned PhysReg = tryAssign(VirtReg, Order, NewVRegs))
return PhysReg;
+ LiveRangeStage Stage = getStage(VirtReg);
+ DEBUG(dbgs() << StageName[Stage]
+ << " Cascade " << ExtraRegInfo[VirtReg.reg].Cascade << '\n');
+
+ // Try to evict a less worthy live range, but only for ranges from the primary
+ // 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_Split)
+ if (unsigned PhysReg = tryEvict(VirtReg, Order, NewVRegs))
+ return PhysReg;
+
assert(NewVRegs.empty() && "Cannot append to existing NewVRegs");
+ // 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_Split) {
+ setStage(VirtReg, RS_Split);
+ DEBUG(dbgs() << "wait for second round\n");
+ NewVRegs.push_back(VirtReg.reg);
+ 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_Done || !VirtReg.isSpillable())
+ return tryLastChanceRecoloring(VirtReg, Order, NewVRegs, FixedRegisters,
+ Depth);
+
// Try splitting VirtReg or interferences.
unsigned PhysReg = trySplit(VirtReg, Order, NewVRegs);
if (PhysReg || !NewVRegs.empty())
return PhysReg;
- // Try to spill another interfering reg with less spill weight.
- PhysReg = trySpillInterferences(VirtReg, Order, NewVRegs);
- if (PhysReg)
- return PhysReg;
-
// Finally spill VirtReg itself.
NamedRegionTimer T("Spiller", TimerGroupName, TimePassesIsEnabled);
- SmallVector<LiveInterval*, 1> pendingSpills;
- spiller().spill(&VirtReg, NewVRegs, pendingSpills);
+ LiveRangeEdit LRE(&VirtReg, NewVRegs, *MF, *LIS, VRM, this);
+ spiller().spill(LRE);
+ setStage(NewVRegs.begin(), NewVRegs.end(), RS_Done);
+
+ if (VerifyEnabled)
+ MF->verify(this, "After spilling");
// The live virtual register requesting allocation was spilled, so tell
// the caller not to allocate anything during this round.
bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
DEBUG(dbgs() << "********** GREEDY REGISTER ALLOCATION **********\n"
- << "********** Function: "
- << ((Value*)mf.getFunction())->getName() << '\n');
+ << "********** Function: " << mf.getName() << '\n');
MF = &mf;
+ TRI = MF->getTarget().getRegisterInfo();
+ TII = MF->getTarget().getInstrInfo();
+ RCI.runOnMachineFunction(mf);
if (VerifyEnabled)
MF->verify(this, "Before greedy register allocator");
- RegAllocBase::init(getAnalysis<VirtRegMap>(), getAnalysis<LiveIntervals>());
+ RegAllocBase::init(getAnalysis<VirtRegMap>(),
+ getAnalysis<LiveIntervals>(),
+ getAnalysis<LiveRegMatrix>());
Indexes = &getAnalysis<SlotIndexes>();
+ MBFI = &getAnalysis<MachineBlockFrequencyInfo>();
DomTree = &getAnalysis<MachineDominatorTree>();
- ReservedRegs = TRI->getReservedRegs(*MF);
SpillerInstance.reset(createInlineSpiller(*this, *MF, *VRM));
Loops = &getAnalysis<MachineLoopInfo>();
- LoopRanges = &getAnalysis<MachineLoopRanges>();
Bundles = &getAnalysis<EdgeBundles>();
SpillPlacer = &getAnalysis<SpillPlacement>();
+ DebugVars = &getAnalysis<LiveDebugVariables>();
- SA.reset(new SplitAnalysis(*MF, *LIS, *Loops));
+ calculateSpillWeightsAndHints(*LIS, mf, *Loops, *MBFI);
- allocatePhysRegs();
- addMBBLiveIns(MF);
+ DEBUG(LIS->dump());
- // Run rewriter
- {
- NamedRegionTimer T("Rewriter", TimerGroupName, TimePassesIsEnabled);
- std::auto_ptr<VirtRegRewriter> rewriter(createVirtRegRewriter());
- rewriter->runOnMachineFunction(*MF, *VRM, LIS);
- }
+ SA.reset(new SplitAnalysis(*VRM, *LIS, *Loops));
+ SE.reset(new SplitEditor(*SA, *LIS, *VRM, *DomTree, *MBFI));
+ ExtraRegInfo.clear();
+ ExtraRegInfo.resize(MRI->getNumVirtRegs());
+ NextCascade = 1;
+ IntfCache.init(MF, Matrix->getLiveUnions(), Indexes, LIS, TRI);
+ GlobalCand.resize(32); // This will grow as needed.
- // The pass output is in VirtRegMap. Release all the transient data.
+ allocatePhysRegs();
releaseMemory();
-
return true;
}
projects / oota-llvm.git / blobdiff