X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FInlineSpiller.cpp;h=59907d9c4e04b37d365d36a627705e237988ed1a;hb=340d596509129de8c3fa9dbe4184a2b148b78757;hp=f0f69872b03a44c27c58bfa22544964ba5f13536;hpb=ae779eea27f41d31268931a6508bd0536cfbc724;p=oota-llvm.git diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp index f0f69872b03..59907d9c4e0 100644 --- a/lib/CodeGen/InlineSpiller.cpp +++ b/lib/CodeGen/InlineSpiller.cpp @@ -17,6 +17,7 @@ #include "LiveRangeEdit.h" #include "VirtRegMap.h" #include "llvm/ADT/Statistic.h" +#include "llvm/ADT/TinyPtrVector.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/CodeGen/LiveIntervalAnalysis.h" #include "llvm/CodeGen/LiveStackAnalysis.h" @@ -27,22 +28,26 @@ #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; STATISTIC(NumSpilledRanges, "Number of spilled live ranges"); -STATISTIC(NumSnippets, "Number of snippets included in spills"); +STATISTIC(NumSnippets, "Number of spilled snippets"); STATISTIC(NumSpills, "Number of spills inserted"); +STATISTIC(NumSpillsRemoved, "Number of spills removed"); STATISTIC(NumReloads, "Number of reloads inserted"); +STATISTIC(NumReloadsRemoved, "Number of reloads removed"); STATISTIC(NumFolded, "Number of folded stack accesses"); STATISTIC(NumFoldedLoads, "Number of folded loads"); STATISTIC(NumRemats, "Number of rematerialized defs for spilling"); -STATISTIC(NumOmitReloadSpill, "Number of omitted spills after reloads"); -STATISTIC(NumHoistLocal, "Number of locally hoisted spills"); -STATISTIC(NumHoistGlobal, "Number of globally hoisted spills"); -STATISTIC(NumRedundantSpills, "Number of redundant spills identified"); +STATISTIC(NumOmitReloadSpill, "Number of omitted spills of reloads"); +STATISTIC(NumHoists, "Number of hoisted spills"); + +static cl::opt DisableHoisting("disable-spill-hoist", cl::Hidden, + cl::desc("Disable inline spill hoisting")); namespace { class InlineSpiller : public Spiller { @@ -75,26 +80,49 @@ class InlineSpiller : public Spiller { // Values that failed to remat at some point. SmallPtrSet UsedValues; +public: // Information about a value that was defined by a copy from a sibling // register. struct SibValueInfo { // True when all reaching defs were reloads: No spill is necessary. bool AllDefsAreReloads; + // True when value is defined by an original PHI not from splitting. + bool DefByOrigPHI; + + // True when the COPY defining this value killed its source. + bool KillsSource; + // The preferred register to spill. unsigned SpillReg; // The value of SpillReg that should be spilled. VNInfo *SpillVNI; + // The block where SpillVNI should be spilled. Currently, this must be the + // block containing SpillVNI->def. + MachineBasicBlock *SpillMBB; + // A defining instruction that is not a sibling copy or a reload, or NULL. // This can be used as a template for rematerialization. MachineInstr *DefMI; + // List of values that depend on this one. These values are actually the + // same, but live range splitting has placed them in different registers, + // or SSA update needed to insert PHI-defs to preserve SSA form. This is + // copies of the current value and phi-kills. Usually only phi-kills cause + // more than one dependent value. + TinyPtrVector Deps; + SibValueInfo(unsigned Reg, VNInfo *VNI) - : AllDefsAreReloads(false), SpillReg(Reg), SpillVNI(VNI), DefMI(0) {} + : AllDefsAreReloads(true), DefByOrigPHI(false), KillsSource(false), + SpillReg(Reg), SpillVNI(VNI), SpillMBB(0), DefMI(0) {} + + // Returns true when a def has been found. + bool hasDef() const { return DefByOrigPHI || DefMI; } }; +private: // Values in RegsToSpill defined by sibling copies. typedef DenseMap SibValueMap; SibValueMap SibValues; @@ -134,6 +162,7 @@ private: bool isSibling(unsigned Reg); MachineInstr *traceSiblingValue(unsigned, VNInfo*, VNInfo*); + void propagateSiblingValue(SibValueMap::iterator, VNInfo *VNI = 0); void analyzeSiblingValues(); bool hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI); @@ -282,6 +311,156 @@ bool InlineSpiller::isSibling(unsigned Reg) { VRM.getOriginal(Reg) == Original; } +#ifndef NDEBUG +static raw_ostream &operator<<(raw_ostream &OS, + const InlineSpiller::SibValueInfo &SVI) { + OS << "spill " << PrintReg(SVI.SpillReg) << ':' + << SVI.SpillVNI->id << '@' << SVI.SpillVNI->def; + if (SVI.SpillMBB) + OS << " in BB#" << SVI.SpillMBB->getNumber(); + if (SVI.AllDefsAreReloads) + OS << " all-reloads"; + if (SVI.DefByOrigPHI) + OS << " orig-phi"; + if (SVI.KillsSource) + OS << " kill"; + OS << " deps["; + for (unsigned i = 0, e = SVI.Deps.size(); i != e; ++i) + OS << ' ' << SVI.Deps[i]->id << '@' << SVI.Deps[i]->def; + OS << " ]"; + if (SVI.DefMI) + OS << " def: " << *SVI.DefMI; + else + OS << '\n'; + return OS; +} +#endif + +/// propagateSiblingValue - Propagate the value in SVI to dependents if it is +/// known. Otherwise remember the dependency for later. +/// +/// @param SVI SibValues entry to propagate. +/// @param VNI Dependent value, or NULL to propagate to all saved dependents. +void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI, + VNInfo *VNI) { + // When VNI is non-NULL, add it to SVI's deps, and only propagate to that. + TinyPtrVector FirstDeps; + if (VNI) { + FirstDeps.push_back(VNI); + SVI->second.Deps.push_back(VNI); + } + + // Has the value been completely determined yet? If not, defer propagation. + if (!SVI->second.hasDef()) + return; + + // Work list of values to propagate. It would be nice to use a SetVector + // here, but then we would be forced to use a SmallSet. + SmallVector WorkList(1, SVI); + SmallPtrSet WorkSet; + + do { + SVI = WorkList.pop_back_val(); + WorkSet.erase(SVI->first); + TinyPtrVector *Deps = VNI ? &FirstDeps : &SVI->second.Deps; + VNI = 0; + + SibValueInfo &SV = SVI->second; + if (!SV.SpillMBB) + SV.SpillMBB = LIS.getMBBFromIndex(SV.SpillVNI->def); + + DEBUG(dbgs() << " prop to " << Deps->size() << ": " + << SVI->first->id << '@' << SVI->first->def << ":\t" << SV); + + assert(SV.hasDef() && "Propagating undefined value"); + + // Should this value be propagated as a preferred spill candidate? We don't + // propagate values of registers that are about to spill. + bool PropSpill = !DisableHoisting && !isRegToSpill(SV.SpillReg); + unsigned SpillDepth = ~0u; + + for (TinyPtrVector::iterator DepI = Deps->begin(), + DepE = Deps->end(); DepI != DepE; ++DepI) { + SibValueMap::iterator DepSVI = SibValues.find(*DepI); + assert(DepSVI != SibValues.end() && "Dependent value not in SibValues"); + SibValueInfo &DepSV = DepSVI->second; + if (!DepSV.SpillMBB) + DepSV.SpillMBB = LIS.getMBBFromIndex(DepSV.SpillVNI->def); + + bool Changed = false; + + // Propagate defining instruction. + if (!DepSV.hasDef()) { + Changed = true; + DepSV.DefMI = SV.DefMI; + DepSV.DefByOrigPHI = SV.DefByOrigPHI; + } + + // Propagate AllDefsAreReloads. For PHI values, this computes an AND of + // all predecessors. + if (!SV.AllDefsAreReloads && DepSV.AllDefsAreReloads) { + Changed = true; + DepSV.AllDefsAreReloads = false; + } + + // Propagate best spill value. + if (PropSpill && SV.SpillVNI != DepSV.SpillVNI) { + if (SV.SpillMBB == DepSV.SpillMBB) { + // DepSV is in the same block. Hoist when dominated. + if (DepSV.KillsSource && SV.SpillVNI->def < DepSV.SpillVNI->def) { + // This is an alternative def earlier in the same MBB. + // Hoist the spill as far as possible in SpillMBB. This can ease + // register pressure: + // + // x = def + // y = use x + // s = copy x + // + // Hoisting the spill of s to immediately after the def removes the + // interference between x and y: + // + // x = def + // spill x + // y = use x + // + // This hoist only helps when the DepSV copy kills its source. + Changed = true; + DepSV.SpillReg = SV.SpillReg; + DepSV.SpillVNI = SV.SpillVNI; + DepSV.SpillMBB = SV.SpillMBB; + } + } else { + // DepSV is in a different block. + if (SpillDepth == ~0u) + SpillDepth = Loops.getLoopDepth(SV.SpillMBB); + + // Also hoist spills to blocks with smaller loop depth, but make sure + // that the new value dominates. Non-phi dependents are always + // dominated, phis need checking. + if ((Loops.getLoopDepth(DepSV.SpillMBB) > SpillDepth) && + (!DepSVI->first->isPHIDef() || + MDT.dominates(SV.SpillMBB, DepSV.SpillMBB))) { + Changed = true; + DepSV.SpillReg = SV.SpillReg; + DepSV.SpillVNI = SV.SpillVNI; + DepSV.SpillMBB = SV.SpillMBB; + } + } + } + + if (!Changed) + continue; + + // Something changed in DepSVI. Propagate to dependents. + if (WorkSet.insert(DepSVI->first)) + WorkList.push_back(DepSVI); + + DEBUG(dbgs() << " update " << DepSVI->first->id << '@' + << DepSVI->first->def << " to:\t" << DepSV); + } + } while (!WorkList.empty()); +} + /// traceSiblingValue - Trace a value that is about to be spilled back to the /// real defining instructions by looking through sibling copies. Always stay /// within the range of OrigVNI so the registers are known to carry the same @@ -294,84 +473,101 @@ bool InlineSpiller::isSibling(unsigned Reg) { /// MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI, VNInfo *OrigVNI) { + // Check if a cached value already exists. + SibValueMap::iterator SVI; + bool Inserted; + tie(SVI, Inserted) = + SibValues.insert(std::make_pair(UseVNI, SibValueInfo(UseReg, UseVNI))); + if (!Inserted) { + DEBUG(dbgs() << "Cached value " << PrintReg(UseReg) << ':' + << UseVNI->id << '@' << UseVNI->def << ' ' << SVI->second); + return SVI->second.DefMI; + } + DEBUG(dbgs() << "Tracing value " << PrintReg(UseReg) << ':' << UseVNI->id << '@' << UseVNI->def << '\n'); - SmallPtrSet Visited; + + // List of (Reg, VNI) that have been inserted into SibValues, but need to be + // processed. SmallVector, 8> WorkList; WorkList.push_back(std::make_pair(UseReg, UseVNI)); - // Best spill candidate seen so far. This must dominate UseVNI. - SibValueInfo SVI(UseReg, UseVNI); - MachineBasicBlock *UseMBB = LIS.getMBBFromIndex(UseVNI->def); - MachineBasicBlock *SpillMBB = UseMBB; - unsigned SpillDepth = Loops.getLoopDepth(SpillMBB); - bool SeenOrigPHI = false; // Original PHI met. - do { unsigned Reg; VNInfo *VNI; tie(Reg, VNI) = WorkList.pop_back_val(); - if (!Visited.insert(VNI)) - continue; + DEBUG(dbgs() << " " << PrintReg(Reg) << ':' << VNI->id << '@' << VNI->def + << ":\t"); - // Is this value a better spill candidate? - if (!isRegToSpill(Reg)) { - MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def); - if (MBB == SpillMBB) { - // This is an alternative def earlier in the same MBB. - // Hoist the spill as far as possible in SpillMBB. This can ease - // register pressure: - // - // x = def - // y = use x - // s = copy x - // - // Hoisting the spill of s to immediately after the def removes the - // interference between x and y: - // - // x = def - // spill x - // y = use x - // - if (VNI->def < SVI.SpillVNI->def) { - DEBUG(dbgs() << " hoist in BB#" << MBB->getNumber() << ": " - << PrintReg(Reg) << ':' << VNI->id << '@' << VNI->def - << '\n'); - SVI.SpillReg = Reg; - SVI.SpillVNI = VNI; - } - } else if (MBB != UseMBB && MDT.dominates(MBB, UseMBB)) { - // This is a valid spill location dominating UseVNI. - // Prefer to spill at a smaller loop depth. - unsigned Depth = Loops.getLoopDepth(MBB); - if (Depth < SpillDepth) { - DEBUG(dbgs() << " spill depth " << Depth << ": " << PrintReg(Reg) - << ':' << VNI->id << '@' << VNI->def << '\n'); - SVI.SpillReg = Reg; - SVI.SpillVNI = VNI; - SpillMBB = MBB; - SpillDepth = Depth; - } - } - } + // First check if this value has already been computed. + SVI = SibValues.find(VNI); + assert(SVI != SibValues.end() && "Missing SibValues entry"); // Trace through PHI-defs created by live range splitting. if (VNI->isPHIDef()) { + // Stop at original PHIs. We don't know the value at the predecessors. if (VNI->def == OrigVNI->def) { - DEBUG(dbgs() << " orig phi value " << PrintReg(Reg) << ':' - << VNI->id << '@' << VNI->def << '\n'); - SeenOrigPHI = true; + DEBUG(dbgs() << "orig phi value\n"); + SVI->second.DefByOrigPHI = true; + SVI->second.AllDefsAreReloads = false; + propagateSiblingValue(SVI); continue; } - // Get values live-out of predecessors. + + // This is a PHI inserted by live range splitting. We could trace the + // live-out value from predecessor blocks, but that search can be very + // expensive if there are many predecessors and many more PHIs as + // generated by tail-dup when it sees an indirectbr. Instead, look at + // all the non-PHI defs that have the same value as OrigVNI. They must + // jointly dominate VNI->def. This is not optimal since VNI may actually + // be jointly dominated by a smaller subset of defs, so there is a change + // we will miss a AllDefsAreReloads optimization. + + // Separate all values dominated by OrigVNI into PHIs and non-PHIs. + SmallVector PHIs, NonPHIs; LiveInterval &LI = LIS.getInterval(Reg); - MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def); - for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(), - PE = MBB->pred_end(); PI != PE; ++PI) { - VNInfo *PVNI = LI.getVNInfoAt(LIS.getMBBEndIdx(*PI).getPrevSlot()); - if (PVNI) - WorkList.push_back(std::make_pair(Reg, PVNI)); + LiveInterval &OrigLI = LIS.getInterval(Original); + + for (LiveInterval::vni_iterator VI = LI.vni_begin(), VE = LI.vni_end(); + VI != VE; ++VI) { + VNInfo *VNI2 = *VI; + if (VNI2->isUnused()) + continue; + if (!OrigLI.containsOneValue() && + OrigLI.getVNInfoAt(VNI2->def) != OrigVNI) + continue; + if (VNI2->isPHIDef() && VNI2->def != OrigVNI->def) + PHIs.push_back(VNI2); + else + NonPHIs.push_back(VNI2); + } + DEBUG(dbgs() << "split phi value, checking " << PHIs.size() + << " phi-defs, and " << NonPHIs.size() + << " non-phi/orig defs\n"); + + // Create entries for all the PHIs. Don't add them to the worklist, we + // are processing all of them in one go here. + for (unsigned i = 0, e = PHIs.size(); i != e; ++i) + SibValues.insert(std::make_pair(PHIs[i], SibValueInfo(Reg, PHIs[i]))); + + // Add every PHI as a dependent of all the non-PHIs. + for (unsigned i = 0, e = NonPHIs.size(); i != e; ++i) { + VNInfo *NonPHI = NonPHIs[i]; + // Known value? Try an insertion. + tie(SVI, Inserted) = + SibValues.insert(std::make_pair(NonPHI, SibValueInfo(Reg, NonPHI))); + // Add all the PHIs as dependents of NonPHI. + for (unsigned pi = 0, pe = PHIs.size(); pi != pe; ++pi) + SVI->second.Deps.push_back(PHIs[pi]); + // This is the first time we see NonPHI, add it to the worklist. + if (Inserted) + WorkList.push_back(std::make_pair(Reg, NonPHI)); + else + // Propagate to all inserted PHIs, not just VNI. + propagateSiblingValue(SVI); } + + // Next work list item. continue; } @@ -382,48 +578,49 @@ MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI, if (unsigned SrcReg = isFullCopyOf(MI, Reg)) { if (isSibling(SrcReg)) { LiveInterval &SrcLI = LIS.getInterval(SrcReg); - VNInfo *SrcVNI = SrcLI.getVNInfoAt(VNI->def.getUseIndex()); - assert(SrcVNI && "Copy from non-existing value"); - DEBUG(dbgs() << " copy of " << PrintReg(SrcReg) << ':' - << SrcVNI->id << '@' << SrcVNI->def << '\n'); - WorkList.push_back(std::make_pair(SrcReg, SrcVNI)); + LiveRange *SrcLR = SrcLI.getLiveRangeContaining(VNI->def.getRegSlot(true)); + assert(SrcLR && "Copy from non-existing value"); + // Check if this COPY kills its source. + SVI->second.KillsSource = (SrcLR->end == VNI->def); + VNInfo *SrcVNI = SrcLR->valno; + DEBUG(dbgs() << "copy of " << PrintReg(SrcReg) << ':' + << SrcVNI->id << '@' << SrcVNI->def + << " kill=" << unsigned(SVI->second.KillsSource) << '\n'); + // Known sibling source value? Try an insertion. + tie(SVI, Inserted) = SibValues.insert(std::make_pair(SrcVNI, + SibValueInfo(SrcReg, SrcVNI))); + // This is the first time we see Src, add it to the worklist. + if (Inserted) + WorkList.push_back(std::make_pair(SrcReg, SrcVNI)); + propagateSiblingValue(SVI, VNI); + // Next work list item. continue; } } // Track reachable reloads. + SVI->second.DefMI = MI; + SVI->second.SpillMBB = MI->getParent(); int FI; if (Reg == TII.isLoadFromStackSlot(MI, FI) && FI == StackSlot) { - DEBUG(dbgs() << " reload " << PrintReg(Reg) << ':' - << VNI->id << "@" << VNI->def << '\n'); - SVI.AllDefsAreReloads = true; + DEBUG(dbgs() << "reload\n"); + propagateSiblingValue(SVI); + // Next work list item. continue; } - // We have an 'original' def. Don't record trivial cases. - if (VNI == UseVNI) { - DEBUG(dbgs() << "Not a sibling copy.\n"); - return MI; - } - // Potential remat candidate. - DEBUG(dbgs() << " def " << PrintReg(Reg) << ':' - << VNI->id << '@' << VNI->def << '\t' << *MI); - SVI.DefMI = MI; + DEBUG(dbgs() << "def " << *MI); + SVI->second.AllDefsAreReloads = false; + propagateSiblingValue(SVI); } while (!WorkList.empty()); - if (SeenOrigPHI || SVI.DefMI) - SVI.AllDefsAreReloads = false; - - DEBUG({ - if (SVI.AllDefsAreReloads) - dbgs() << "All defs are reloads.\n"; - else - dbgs() << "Prefer to spill " << PrintReg(SVI.SpillReg) << ':' - << SVI.SpillVNI->id << '@' << SVI.SpillVNI->def << '\n'; - }); - SibValues.insert(std::make_pair(UseVNI, SVI)); - return SVI.DefMI; + // Look up the value we were looking for. We already did this lokup at the + // top of the function, but SibValues may have been invalidated. + SVI = SibValues.find(UseVNI); + assert(SVI != SibValues.end() && "Didn't compute requested info"); + DEBUG(dbgs() << " traced to:\t" << SVI->second); + return SVI->second.DefMI; } /// analyzeSiblingValues - Trace values defined by sibling copies back to @@ -468,8 +665,8 @@ void InlineSpiller::analyzeSiblingValues() { /// a spill at a better location. bool InlineSpiller::hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI) { SlotIndex Idx = LIS.getInstructionIndex(CopyMI); - VNInfo *VNI = SpillLI.getVNInfoAt(Idx.getDefIndex()); - assert(VNI && VNI->def == Idx.getDefIndex() && "Not defined by copy"); + VNInfo *VNI = SpillLI.getVNInfoAt(Idx.getRegSlot()); + assert(VNI && VNI->def == Idx.getRegSlot() && "Not defined by copy"); SibValueMap::iterator I = SibValues.find(VNI); if (I == SibValues.end()) return false; @@ -506,6 +703,7 @@ bool InlineSpiller::hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI) { // Already spilled everywhere. if (SVI.AllDefsAreReloads) { + DEBUG(dbgs() << "\tno spill needed: " << SVI); ++NumOmitReloadSpill; return true; } @@ -528,13 +726,10 @@ bool InlineSpiller::hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI) { MRI.getRegClass(SVI.SpillReg), &TRI); --MII; // Point to store instruction. LIS.InsertMachineInstrInMaps(MII); - VRM.addSpillSlotUse(StackSlot, MII); DEBUG(dbgs() << "\thoisted: " << SVI.SpillVNI->def << '\t' << *MII); - if (MBB == CopyMI->getParent()) - ++NumHoistLocal; - else - ++NumHoistGlobal; + ++NumSpills; + ++NumHoists; return true; } @@ -574,9 +769,9 @@ void InlineSpiller::eliminateRedundantSpills(LiveInterval &SLI, VNInfo *VNI) { if (unsigned DstReg = isFullCopyOf(MI, Reg)) { if (isSibling(DstReg)) { LiveInterval &DstLI = LIS.getInterval(DstReg); - VNInfo *DstVNI = DstLI.getVNInfoAt(Idx.getDefIndex()); + VNInfo *DstVNI = DstLI.getVNInfoAt(Idx.getRegSlot()); assert(DstVNI && "Missing defined value"); - assert(DstVNI->def == Idx.getDefIndex() && "Wrong copy def slot"); + assert(DstVNI->def == Idx.getRegSlot() && "Wrong copy def slot"); WorkList.push_back(std::make_pair(&DstLI, DstVNI)); } continue; @@ -589,7 +784,8 @@ void InlineSpiller::eliminateRedundantSpills(LiveInterval &SLI, VNInfo *VNI) { // eliminateDeadDefs won't normally remove stores, so switch opcode. MI->setDesc(TII.get(TargetOpcode::KILL)); DeadDefs.push_back(MI); - ++NumRedundantSpills; + ++NumSpillsRemoved; + --NumSpills; } } } while (!WorkList.empty()); @@ -614,7 +810,7 @@ void InlineSpiller::markValueUsed(LiveInterval *LI, VNInfo *VNI) { MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def); for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(), PE = MBB->pred_end(); PI != PE; ++PI) { - VNInfo *PVNI = LI->getVNInfoAt(LIS.getMBBEndIdx(*PI).getPrevSlot()); + VNInfo *PVNI = LI->getVNInfoBefore(LIS.getMBBEndIdx(*PI)); if (PVNI) WorkList.push_back(std::make_pair(LI, PVNI)); } @@ -627,7 +823,7 @@ void InlineSpiller::markValueUsed(LiveInterval *LI, VNInfo *VNI) { continue; LiveInterval &SnipLI = LIS.getInterval(MI->getOperand(1).getReg()); assert(isRegToSpill(SnipLI.reg) && "Unexpected register in copy"); - VNInfo *SnipVNI = SnipLI.getVNInfoAt(VNI->def.getUseIndex()); + VNInfo *SnipVNI = SnipLI.getVNInfoAt(VNI->def.getRegSlot(true)); assert(SnipVNI && "Snippet undefined before copy"); WorkList.push_back(std::make_pair(&SnipLI, SnipVNI)); } while (!WorkList.empty()); @@ -636,7 +832,7 @@ void InlineSpiller::markValueUsed(LiveInterval *LI, VNInfo *VNI) { /// reMaterializeFor - Attempt to rematerialize before MI instead of reloading. bool InlineSpiller::reMaterializeFor(LiveInterval &VirtReg, MachineBasicBlock::iterator MI) { - SlotIndex UseIdx = LIS.getInstructionIndex(MI).getUseIndex(); + SlotIndex UseIdx = LIS.getInstructionIndex(MI).getRegSlot(true); VNInfo *ParentVNI = VirtReg.getVNInfoAt(UseIdx.getBaseIndex()); if (!ParentVNI) { @@ -710,7 +906,7 @@ bool InlineSpiller::reMaterializeFor(LiveInterval &VirtReg, DEBUG(dbgs() << "\t " << UseIdx << '\t' << *MI); VNInfo *DefVNI = NewLI.getNextValue(DefIdx, 0, LIS.getVNInfoAllocator()); - NewLI.addRange(LiveRange(DefIdx, UseIdx.getDefIndex(), DefVNI)); + NewLI.addRange(LiveRange(DefIdx, UseIdx.getRegSlot(), DefVNI)); DEBUG(dbgs() << "\tinterval: " << NewLI << '\n'); ++NumRemats; return true; @@ -787,10 +983,10 @@ void InlineSpiller::reMaterializeAll() { /// If MI is a load or store of StackSlot, it can be removed. bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) { int FI = 0; - unsigned InstrReg; - if (!(InstrReg = TII.isLoadFromStackSlot(MI, FI)) && - !(InstrReg = TII.isStoreToStackSlot(MI, FI))) - return false; + unsigned InstrReg = TII.isLoadFromStackSlot(MI, FI); + bool IsLoad = InstrReg; + if (!IsLoad) + InstrReg = TII.isStoreToStackSlot(MI, FI); // We have a stack access. Is it the right register and slot? if (InstrReg != Reg || FI != StackSlot) @@ -799,6 +995,15 @@ bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) { DEBUG(dbgs() << "Coalescing stack access: " << *MI); LIS.RemoveMachineInstrFromMaps(MI); MI->eraseFromParent(); + + if (IsLoad) { + ++NumReloadsRemoved; + --NumReloads; + } else { + ++NumSpillsRemoved; + --NumSpills; + } + return true; } @@ -810,14 +1015,19 @@ bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) { bool InlineSpiller::foldMemoryOperand(MachineBasicBlock::iterator MI, const SmallVectorImpl &Ops, MachineInstr *LoadMI) { + bool WasCopy = MI->isCopy(); + unsigned ImpReg = 0; + // TargetInstrInfo::foldMemoryOperand only expects explicit, non-tied // operands. SmallVector FoldOps; for (unsigned i = 0, e = Ops.size(); i != e; ++i) { unsigned Idx = Ops[i]; MachineOperand &MO = MI->getOperand(Idx); - if (MO.isImplicit()) + if (MO.isImplicit()) { + ImpReg = MO.getReg(); continue; + } // FIXME: Teach targets to deal with subregs. if (MO.getSubReg()) return false; @@ -835,11 +1045,27 @@ bool InlineSpiller::foldMemoryOperand(MachineBasicBlock::iterator MI, if (!FoldMI) return false; LIS.ReplaceMachineInstrInMaps(MI, FoldMI); - if (!LoadMI) - VRM.addSpillSlotUse(StackSlot, FoldMI); MI->eraseFromParent(); - DEBUG(dbgs() << "\tfolded: " << *FoldMI); - ++NumFolded; + + // TII.foldMemoryOperand may have left some implicit operands on the + // instruction. Strip them. + if (ImpReg) + for (unsigned i = FoldMI->getNumOperands(); i; --i) { + MachineOperand &MO = FoldMI->getOperand(i - 1); + if (!MO.isReg() || !MO.isImplicit()) + break; + if (MO.getReg() == ImpReg) + FoldMI->RemoveOperand(i - 1); + } + + DEBUG(dbgs() << "\tfolded: " << LIS.getInstructionIndex(FoldMI) << '\t' + << *FoldMI); + if (!WasCopy) + ++NumFolded; + else if (Ops.front() == 0) + ++NumSpills; + else + ++NumReloads; return true; } @@ -851,8 +1077,7 @@ void InlineSpiller::insertReload(LiveInterval &NewLI, TII.loadRegFromStackSlot(MBB, MI, NewLI.reg, StackSlot, MRI.getRegClass(NewLI.reg), &TRI); --MI; // Point to load instruction. - SlotIndex LoadIdx = LIS.InsertMachineInstrInMaps(MI).getDefIndex(); - VRM.addSpillSlotUse(StackSlot, MI); + SlotIndex LoadIdx = LIS.InsertMachineInstrInMaps(MI).getRegSlot(); DEBUG(dbgs() << "\treload: " << LoadIdx << '\t' << *MI); VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, 0, LIS.getVNInfoAllocator()); @@ -867,8 +1092,7 @@ void InlineSpiller::insertSpill(LiveInterval &NewLI, const LiveInterval &OldLI, TII.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, StackSlot, MRI.getRegClass(NewLI.reg), &TRI); --MI; // Point to store instruction. - SlotIndex StoreIdx = LIS.InsertMachineInstrInMaps(MI).getDefIndex(); - VRM.addSpillSlotUse(StackSlot, MI); + SlotIndex StoreIdx = LIS.InsertMachineInstrInMaps(MI).getRegSlot(); DEBUG(dbgs() << "\tspilled: " << StoreIdx << '\t' << *MI); VNInfo *StoreVNI = NewLI.getNextValue(Idx, 0, LIS.getVNInfoAllocator()); NewLI.addRange(LiveRange(Idx, StoreIdx, StoreVNI)); @@ -917,8 +1141,8 @@ void InlineSpiller::spillAroundUses(unsigned Reg) { // Find the slot index where this instruction reads and writes OldLI. // This is usually the def slot, except for tied early clobbers. - SlotIndex Idx = LIS.getInstructionIndex(MI).getDefIndex(); - if (VNInfo *VNI = OldLI.getVNInfoAt(Idx.getUseIndex())) + SlotIndex Idx = LIS.getInstructionIndex(MI).getRegSlot(); + if (VNInfo *VNI = OldLI.getVNInfoAt(Idx.getRegSlot(true))) if (SlotIndex::isSameInstr(Idx, VNI->def)) Idx = VNI->def; @@ -975,8 +1199,16 @@ void InlineSpiller::spillAroundUses(unsigned Reg) { DEBUG(dbgs() << "\trewrite: " << Idx << '\t' << *MI); // FIXME: Use a second vreg if instruction has no tied ops. - if (Writes && hasLiveDef) + if (Writes) { + if (hasLiveDef) insertSpill(NewLI, OldLI, Idx, MI); + else { + // This instruction defines a dead value. We don't need to spill it, + // but do create a live range for the dead value. + VNInfo *VNI = NewLI.getNextValue(Idx, 0, LIS.getVNInfoAllocator()); + NewLI.addRange(LiveRange(Idx, Idx.getDeadSlot(), VNI)); + } + } DEBUG(dbgs() << "\tinterval: " << NewLI << '\n'); } @@ -1017,7 +1249,6 @@ void InlineSpiller::spillAll() { MachineInstr *MI = RI.skipInstruction();) { assert(SnippetCopies.count(MI) && "Remaining use wasn't a snippet copy"); // FIXME: Do this with a LiveRangeEdit callback. - VRM.RemoveMachineInstrFromMaps(MI); LIS.RemoveMachineInstrFromMaps(MI); MI->eraseFromParent(); }