#include "VirtRegMap.h"
#include "llvm/Value.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/CodeGen/CalcSpillWeights.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
cl::init(false), cl::Hidden);
STATISTIC(numIntervals , "Number of original intervals");
-STATISTIC(numFolds , "Number of loads/stores folded into instructions");
-STATISTIC(numSplits , "Number of intervals split");
char LiveIntervals::ID = 0;
INITIALIZE_PASS_BEGIN(LiveIntervals, "liveintervals",
printInstrs(dbgs());
}
-bool LiveIntervals::conflictsWithPhysReg(const LiveInterval &li,
- VirtRegMap &vrm, unsigned reg) {
- // We don't handle fancy stuff crossing basic block boundaries
- if (li.ranges.size() != 1)
- return true;
- const LiveRange &range = li.ranges.front();
- SlotIndex idx = range.start.getBaseIndex();
- SlotIndex end = range.end.getPrevSlot().getBaseIndex().getNextIndex();
-
- // Skip deleted instructions
- MachineInstr *firstMI = getInstructionFromIndex(idx);
- while (!firstMI && idx != end) {
- idx = idx.getNextIndex();
- firstMI = getInstructionFromIndex(idx);
- }
- if (!firstMI)
- return false;
-
- // Find last instruction in range
- SlotIndex lastIdx = end.getPrevIndex();
- MachineInstr *lastMI = getInstructionFromIndex(lastIdx);
- while (!lastMI && lastIdx != idx) {
- lastIdx = lastIdx.getPrevIndex();
- lastMI = getInstructionFromIndex(lastIdx);
- }
- if (!lastMI)
- return false;
-
- // Range cannot cross basic block boundaries or terminators
- MachineBasicBlock *MBB = firstMI->getParent();
- if (MBB != lastMI->getParent() || lastMI->getDesc().isTerminator())
- return true;
-
- MachineBasicBlock::const_iterator E = lastMI;
- ++E;
- for (MachineBasicBlock::const_iterator I = firstMI; I != E; ++I) {
- const MachineInstr &MI = *I;
-
- // Allow copies to and from li.reg
- if (MI.isCopy())
- if (MI.getOperand(0).getReg() == li.reg ||
- MI.getOperand(1).getReg() == li.reg)
- continue;
-
- // Check for operands using reg
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- const MachineOperand& mop = MI.getOperand(i);
- if (!mop.isReg())
- continue;
- unsigned PhysReg = mop.getReg();
- if (PhysReg == 0 || PhysReg == li.reg)
- continue;
- if (TargetRegisterInfo::isVirtualRegister(PhysReg)) {
- if (!vrm.hasPhys(PhysReg))
- continue;
- PhysReg = vrm.getPhys(PhysReg);
- }
- if (PhysReg && tri_->regsOverlap(PhysReg, reg))
- return true;
- }
- }
-
- // No conflicts found.
- return false;
-}
-
-bool LiveIntervals::conflictsWithAliasRef(LiveInterval &li, unsigned Reg,
- SmallPtrSet<MachineInstr*,32> &JoinedCopies) {
- for (LiveInterval::Ranges::const_iterator
- I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
- for (SlotIndex index = I->start.getBaseIndex(),
- end = I->end.getPrevSlot().getBaseIndex().getNextIndex();
- index != end;
- index = index.getNextIndex()) {
- MachineInstr *MI = getInstructionFromIndex(index);
- if (!MI)
- continue; // skip deleted instructions
-
- if (JoinedCopies.count(MI))
- continue;
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand& MO = MI->getOperand(i);
- if (!MO.isReg())
- continue;
- unsigned PhysReg = MO.getReg();
- if (PhysReg == 0 || PhysReg == Reg ||
- TargetRegisterInfo::isVirtualRegister(PhysReg))
- continue;
- if (tri_->regsOverlap(Reg, PhysReg))
- return true;
- }
- }
- }
-
- return false;
-}
-
static
bool MultipleDefsBySameMI(const MachineInstr &MI, unsigned MOIdx) {
unsigned Reg = MI.getOperand(MOIdx).getReg();
if (!MO.getSubReg() || MO.isEarlyClobber())
return false;
- SlotIndex RedefIndex = MIIdx.getDefIndex();
+ SlotIndex RedefIndex = MIIdx.getRegSlot();
const LiveRange *OldLR =
- interval.getLiveRangeContaining(RedefIndex.getUseIndex());
+ interval.getLiveRangeContaining(RedefIndex.getRegSlot(true));
MachineInstr *DefMI = getInstructionFromIndex(OldLR->valno->def);
if (DefMI != 0) {
return DefMI->findRegisterDefOperandIdx(interval.reg) != -1;
LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg);
if (interval.empty()) {
// Get the Idx of the defining instructions.
- SlotIndex defIndex = MIIdx.getDefIndex();
- // Earlyclobbers move back one, so that they overlap the live range
- // of inputs.
- if (MO.isEarlyClobber())
- defIndex = MIIdx.getUseIndex();
+ SlotIndex defIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
// Make sure the first definition is not a partial redefinition. Add an
// <imp-def> of the full register.
- if (MO.getSubReg())
+ // FIXME: LiveIntervals shouldn't modify the code like this. Whoever
+ // created the machine instruction should annotate it with <undef> flags
+ // as needed. Then we can simply assert here. The REG_SEQUENCE lowering
+ // is the main suspect.
+ if (MO.getSubReg()) {
mi->addRegisterDefined(interval.reg);
+ // Mark all defs of interval.reg on this instruction as reading <undef>.
+ for (unsigned i = MOIdx, e = mi->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO2 = mi->getOperand(i);
+ if (MO2.isReg() && MO2.getReg() == interval.reg && MO2.getSubReg())
+ MO2.setIsUndef();
+ }
+ }
MachineInstr *CopyMI = NULL;
if (mi->isCopyLike()) {
// FIXME: what about dead vars?
SlotIndex killIdx;
if (vi.Kills[0] != mi)
- killIdx = getInstructionIndex(vi.Kills[0]).getDefIndex();
+ killIdx = getInstructionIndex(vi.Kills[0]).getRegSlot();
else
- killIdx = defIndex.getStoreIndex();
+ killIdx = defIndex.getDeadSlot();
// If the kill happens after the definition, we have an intra-block
// live range.
for (unsigned i = 0, e = vi.Kills.size(); i != e; ++i) {
MachineInstr *Kill = vi.Kills[i];
SlotIndex Start = getMBBStartIdx(Kill->getParent());
- SlotIndex killIdx = getInstructionIndex(Kill).getDefIndex();
+ SlotIndex killIdx = getInstructionIndex(Kill).getRegSlot();
// Create interval with one of a NEW value number. Note that this value
// number isn't actually defined by an instruction, weird huh? :)
// are actually two values in the live interval. Because of this we
// need to take the LiveRegion that defines this register and split it
// into two values.
- SlotIndex RedefIndex = MIIdx.getDefIndex();
- if (MO.isEarlyClobber())
- RedefIndex = MIIdx.getUseIndex();
+ SlotIndex RedefIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
const LiveRange *OldLR =
- interval.getLiveRangeContaining(RedefIndex.getUseIndex());
+ interval.getLiveRangeContaining(RedefIndex.getRegSlot(true));
VNInfo *OldValNo = OldLR->valno;
- SlotIndex DefIndex = OldValNo->def.getDefIndex();
+ SlotIndex DefIndex = OldValNo->def.getRegSlot();
// Delete the previous value, which should be short and continuous,
// because the 2-addr copy must be in the same MBB as the redef.
// If this redefinition is dead, we need to add a dummy unit live
// range covering the def slot.
if (MO.isDead())
- interval.addRange(LiveRange(RedefIndex, RedefIndex.getStoreIndex(),
+ interval.addRange(LiveRange(RedefIndex, RedefIndex.getDeadSlot(),
OldValNo));
DEBUG({
// live until the end of the block. We've already taken care of the
// rest of the live range.
- SlotIndex defIndex = MIIdx.getDefIndex();
+ SlotIndex defIndex = MIIdx.getRegSlot();
if (MO.isEarlyClobber())
- defIndex = MIIdx.getUseIndex();
+ defIndex = MIIdx.getRegSlot(true);
VNInfo *ValNo;
MachineInstr *CopyMI = NULL;
DEBUG(dbgs() << "\t\tregister: " << PrintReg(interval.reg, tri_));
SlotIndex baseIndex = MIIdx;
- SlotIndex start = baseIndex.getDefIndex();
- // Earlyclobbers move back one.
- if (MO.isEarlyClobber())
- start = MIIdx.getUseIndex();
+ SlotIndex start = baseIndex.getRegSlot(MO.isEarlyClobber());
SlotIndex end = start;
// If it is not used after definition, it is considered dead at
// advance below compensates.
if (MO.isDead()) {
DEBUG(dbgs() << " dead");
- end = start.getStoreIndex();
+ end = start.getDeadSlot();
goto exit;
}
if (mi->killsRegister(interval.reg, tri_)) {
DEBUG(dbgs() << " killed");
- end = baseIndex.getDefIndex();
+ end = baseIndex.getRegSlot();
goto exit;
} else {
int DefIdx = mi->findRegisterDefOperandIdx(interval.reg,false,false,tri_);
if (DefIdx != -1) {
if (mi->isRegTiedToUseOperand(DefIdx)) {
// Two-address instruction.
- end = baseIndex.getDefIndex();
+ end = baseIndex.getRegSlot();
} else {
// Another instruction redefines the register before it is ever read.
// Then the register is essentially dead at the instruction that
// defines it. Hence its interval is:
// [defSlot(def), defSlot(def)+1)
DEBUG(dbgs() << " dead");
- end = start.getStoreIndex();
+ end = start.getDeadSlot();
}
goto exit;
}
// instruction where we know it's dead is if it is live-in to the function
// and never used. Another possible case is the implicit use of the
// physical register has been deleted by two-address pass.
- end = start.getStoreIndex();
+ end = start.getDeadSlot();
exit:
assert(start < end && "did not find end of interval?");
if (TargetRegisterInfo::isVirtualRegister(MO.getReg()))
handleVirtualRegisterDef(MBB, MI, MIIdx, MO, MOIdx,
getOrCreateInterval(MO.getReg()));
- else if (allocatableRegs_[MO.getReg()]) {
+ else {
MachineInstr *CopyMI = NULL;
if (MI->isCopyLike())
CopyMI = MI;
handlePhysicalRegisterDef(MBB, MI, MIIdx, MO,
getOrCreateInterval(MO.getReg()), CopyMI);
- // Def of a register also defines its sub-registers.
- for (const unsigned* AS = tri_->getSubRegisters(MO.getReg()); *AS; ++AS)
- // If MI also modifies the sub-register explicitly, avoid processing it
- // more than once. Do not pass in TRI here so it checks for exact match.
- if (!MI->definesRegister(*AS))
- handlePhysicalRegisterDef(MBB, MI, MIIdx, MO,
- getOrCreateInterval(*AS), 0);
}
}
while (mi != E) {
if (mi->killsRegister(interval.reg, tri_)) {
DEBUG(dbgs() << " killed");
- end = baseIndex.getDefIndex();
+ end = baseIndex.getRegSlot();
SeenDefUse = true;
break;
} else if (mi->definesRegister(interval.reg, tri_)) {
// it. Hence its interval is:
// [defSlot(def), defSlot(def)+1)
DEBUG(dbgs() << " dead");
- end = start.getStoreIndex();
+ end = start.getDeadSlot();
SeenDefUse = true;
break;
}
if (!SeenDefUse) {
if (isAlias) {
DEBUG(dbgs() << " dead");
- end = MIIdx.getStoreIndex();
+ end = MIIdx.getDeadSlot();
} else {
DEBUG(dbgs() << " live through");
- end = baseIndex;
+ end = getMBBEndIdx(MBB);
}
}
/// shrinkToUses - After removing some uses of a register, shrink its live
/// range to just the remaining uses. This method does not compute reaching
/// defs for new uses, and it doesn't remove dead defs.
-void LiveIntervals::shrinkToUses(LiveInterval *li) {
+bool LiveIntervals::shrinkToUses(LiveInterval *li,
+ SmallVectorImpl<MachineInstr*> *dead) {
DEBUG(dbgs() << "Shrink: " << *li << '\n');
assert(TargetRegisterInfo::isVirtualRegister(li->reg)
&& "Can't only shrink physical registers");
// Find all the values used, including PHI kills.
SmallVector<std::pair<SlotIndex, VNInfo*>, 16> WorkList;
+ // Blocks that have already been added to WorkList as live-out.
+ SmallPtrSet<MachineBasicBlock*, 16> LiveOut;
+
// Visit all instructions reading li->reg.
for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(li->reg);
MachineInstr *UseMI = I.skipInstruction();) {
if (UseMI->isDebugValue() || !UseMI->readsVirtualRegister(li->reg))
continue;
- SlotIndex Idx = getInstructionIndex(UseMI).getUseIndex();
- VNInfo *VNI = li->getVNInfoAt(Idx);
- assert(VNI && "Live interval not live into reading instruction");
- if (VNI->def == Idx) {
- // Special case: An early-clobber tied operand reads and writes the
- // register one slot early.
- Idx = Idx.getPrevSlot();
- VNI = li->getVNInfoAt(Idx);
+ SlotIndex Idx = getInstructionIndex(UseMI).getRegSlot();
+ // Note: This intentionally picks up the wrong VNI in case of an EC redef.
+ // See below.
+ VNInfo *VNI = li->getVNInfoBefore(Idx);
+ if (!VNI) {
+ // This shouldn't happen: readsVirtualRegister returns true, but there is
+ // no live value. It is likely caused by a target getting <undef> flags
+ // wrong.
+ DEBUG(dbgs() << Idx << '\t' << *UseMI
+ << "Warning: Instr claims to read non-existent value in "
+ << *li << '\n');
+ continue;
+ }
+ // Special case: An early-clobber tied operand reads and writes the
+ // register one slot early. The getVNInfoBefore call above would have
+ // picked up the value defined by UseMI. Adjust the kill slot and value.
+ if (SlotIndex::isSameInstr(VNI->def, Idx)) {
+ Idx = VNI->def;
+ VNI = li->getVNInfoBefore(Idx);
assert(VNI && "Early-clobber tied value not available");
}
WorkList.push_back(std::make_pair(Idx, VNI));
VNInfo *VNI = *I;
if (VNI->isUnused())
continue;
- NewLI.addRange(LiveRange(VNI->def, VNI->def.getNextSlot(), VNI));
+ NewLI.addRange(LiveRange(VNI->def, VNI->def.getDeadSlot(), VNI));
}
+ // Keep track of the PHIs that are in use.
+ SmallPtrSet<VNInfo*, 8> UsedPHIs;
+
// Extend intervals to reach all uses in WorkList.
while (!WorkList.empty()) {
SlotIndex Idx = WorkList.back().first;
VNInfo *VNI = WorkList.back().second;
WorkList.pop_back();
+ const MachineBasicBlock *MBB = getMBBFromIndex(Idx.getPrevSlot());
+ SlotIndex BlockStart = getMBBStartIdx(MBB);
// Extend the live range for VNI to be live at Idx.
- LiveInterval::iterator I = NewLI.find(Idx);
-
- // Already got it?
- if (I != NewLI.end() && I->start <= Idx) {
- assert(I->valno == VNI && "Unexpected existing value number");
- continue;
- }
-
- // Is there already a live range in the block containing Idx?
- const MachineBasicBlock *MBB = getMBBFromIndex(Idx);
- SlotIndex BlockStart = getMBBStartIdx(MBB);
- DEBUG(dbgs() << "Shrink: Use val#" << VNI->id << " at " << Idx
- << " in BB#" << MBB->getNumber() << '@' << BlockStart);
- if (I != NewLI.begin() && (--I)->end > BlockStart) {
- assert(I->valno == VNI && "Wrong reaching def");
- DEBUG(dbgs() << " extend [" << I->start << ';' << I->end << ")\n");
- // Is this the first use of a PHIDef in its defining block?
- if (VNI->isPHIDef() && I->end == VNI->def.getNextSlot()) {
- // The PHI is live, make sure the predecessors are live-out.
- for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- SlotIndex Stop = getMBBEndIdx(*PI).getPrevSlot();
- VNInfo *PVNI = li->getVNInfoAt(Stop);
- // A predecessor is not required to have a live-out value for a PHI.
- if (PVNI) {
- assert(PVNI->hasPHIKill() && "Missing hasPHIKill flag");
- WorkList.push_back(std::make_pair(Stop, PVNI));
- }
- }
+ if (VNInfo *ExtVNI = NewLI.extendInBlock(BlockStart, Idx)) {
+ (void)ExtVNI;
+ assert(ExtVNI == VNI && "Unexpected existing value number");
+ // Is this a PHIDef we haven't seen before?
+ if (!VNI->isPHIDef() || VNI->def != BlockStart || !UsedPHIs.insert(VNI))
+ continue;
+ // The PHI is live, make sure the predecessors are live-out.
+ for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ if (!LiveOut.insert(*PI))
+ continue;
+ SlotIndex Stop = getMBBEndIdx(*PI);
+ // A predecessor is not required to have a live-out value for a PHI.
+ if (VNInfo *PVNI = li->getVNInfoBefore(Stop))
+ WorkList.push_back(std::make_pair(Stop, PVNI));
}
-
- // Extend the live range in the block to include Idx.
- NewLI.addRange(LiveRange(I->end, Idx.getNextSlot(), VNI));
continue;
}
// VNI is live-in to MBB.
DEBUG(dbgs() << " live-in at " << BlockStart << '\n');
- NewLI.addRange(LiveRange(BlockStart, Idx.getNextSlot(), VNI));
+ NewLI.addRange(LiveRange(BlockStart, Idx, VNI));
// Make sure VNI is live-out from the predecessors.
for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI) {
- SlotIndex Stop = getMBBEndIdx(*PI).getPrevSlot();
- assert(li->getVNInfoAt(Stop) == VNI && "Wrong value out of predecessor");
+ if (!LiveOut.insert(*PI))
+ continue;
+ SlotIndex Stop = getMBBEndIdx(*PI);
+ assert(li->getVNInfoBefore(Stop) == VNI &&
+ "Wrong value out of predecessor");
WorkList.push_back(std::make_pair(Stop, VNI));
}
}
// Handle dead values.
+ bool CanSeparate = false;
for (LiveInterval::vni_iterator I = li->vni_begin(), E = li->vni_end();
I != E; ++I) {
VNInfo *VNI = *I;
continue;
LiveInterval::iterator LII = NewLI.FindLiveRangeContaining(VNI->def);
assert(LII != NewLI.end() && "Missing live range for PHI");
- if (LII->end != VNI->def.getNextSlot())
+ if (LII->end != VNI->def.getDeadSlot())
continue;
- if (!VNI->isPHIDef()) {
+ if (VNI->isPHIDef()) {
// This is a dead PHI. Remove it.
VNI->setIsUnused(true);
NewLI.removeRange(*LII);
+ DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n");
+ CanSeparate = true;
} else {
// This is a dead def. Make sure the instruction knows.
MachineInstr *MI = getInstructionFromIndex(VNI->def);
assert(MI && "No instruction defining live value");
MI->addRegisterDead(li->reg, tri_);
+ if (dead && MI->allDefsAreDead()) {
+ DEBUG(dbgs() << "All defs dead: " << VNI->def << '\t' << *MI);
+ dead->push_back(MI);
+ }
}
}
// Move the trimmed ranges back.
li->ranges.swap(NewLI.ranges);
- DEBUG(dbgs() << "Shrink: " << *li << '\n');
+ DEBUG(dbgs() << "Shrunk: " << *li << '\n');
+ return CanSeparate;
}
MachineBasicBlock::iterator
LiveIntervals::getLastSplitPoint(const LiveInterval &li,
- MachineBasicBlock *mbb) {
+ MachineBasicBlock *mbb) const {
const MachineBasicBlock *lpad = mbb->getLandingPadSuccessor();
// If li is not live into a landing pad, we can insert spill code before the
MachineBasicBlock::iterator I = mbb->end(), B = mbb->begin();
while (I != B) {
--I;
- if (I->getDesc().isCall())
+ if (I->isCall())
return I;
}
// The block contains no calls that can throw, so use the first terminator.
return mbb->getFirstTerminator();
}
+void LiveIntervals::addKillFlags() {
+ for (iterator I = begin(), E = end(); I != E; ++I) {
+ unsigned Reg = I->first;
+ if (TargetRegisterInfo::isPhysicalRegister(Reg))
+ continue;
+ if (mri_->reg_nodbg_empty(Reg))
+ continue;
+ LiveInterval *LI = I->second;
+
+ // Every instruction that kills Reg corresponds to a live range end point.
+ for (LiveInterval::iterator RI = LI->begin(), RE = LI->end(); RI != RE;
+ ++RI) {
+ // A block index indicates an MBB edge.
+ if (RI->end.isBlock())
+ continue;
+ MachineInstr *MI = getInstructionFromIndex(RI->end);
+ if (!MI)
+ continue;
+ MI->addRegisterKilled(Reg, NULL);
+ }
+ }
+}
+
/// getReMatImplicitUse - If the remat definition MI has one (for now, we only
/// allow one) virtual register operand, then its uses are implicitly using
/// the register. Returns the virtual register.
bool
LiveIntervals::isReMaterializable(const LiveInterval &li,
const VNInfo *ValNo, MachineInstr *MI,
- const SmallVectorImpl<LiveInterval*> &SpillIs,
+ const SmallVectorImpl<LiveInterval*> *SpillIs,
bool &isLoad) {
if (DisableReMat)
return false;
// If a register operand of the re-materialized instruction is going to
// be spilled next, then it's not legal to re-materialize this instruction.
- for (unsigned i = 0, e = SpillIs.size(); i != e; ++i)
- if (ImpUse == SpillIs[i]->reg)
- return false;
+ if (SpillIs)
+ for (unsigned i = 0, e = SpillIs->size(); i != e; ++i)
+ if (ImpUse == (*SpillIs)[i]->reg)
+ return false;
}
return true;
}
-/// isReMaterializable - Returns true if the definition MI of the specified
-/// val# of the specified interval is re-materializable.
-bool LiveIntervals::isReMaterializable(const LiveInterval &li,
- const VNInfo *ValNo, MachineInstr *MI) {
- SmallVector<LiveInterval*, 4> Dummy1;
- bool Dummy2;
- return isReMaterializable(li, ValNo, MI, Dummy1, Dummy2);
-}
-
/// isReMaterializable - Returns true if every definition of MI of every
/// val# of the specified interval is re-materializable.
bool
LiveIntervals::isReMaterializable(const LiveInterval &li,
- const SmallVectorImpl<LiveInterval*> &SpillIs,
+ const SmallVectorImpl<LiveInterval*> *SpillIs,
bool &isLoad) {
isLoad = false;
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
return true;
}
-/// FilterFoldedOps - Filter out two-address use operands. Return
-/// true if it finds any issue with the operands that ought to prevent
-/// folding.
-static bool FilterFoldedOps(MachineInstr *MI,
- SmallVector<unsigned, 2> &Ops,
- unsigned &MRInfo,
- SmallVector<unsigned, 2> &FoldOps) {
- MRInfo = 0;
- for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
- unsigned OpIdx = Ops[i];
- MachineOperand &MO = MI->getOperand(OpIdx);
- // FIXME: fold subreg use.
- if (MO.getSubReg())
- return true;
- if (MO.isDef())
- MRInfo |= (unsigned)VirtRegMap::isMod;
- else {
- // Filter out two-address use operand(s).
- if (MI->isRegTiedToDefOperand(OpIdx)) {
- MRInfo = VirtRegMap::isModRef;
- continue;
- }
- MRInfo |= (unsigned)VirtRegMap::isRef;
- }
- FoldOps.push_back(OpIdx);
- }
- return false;
-}
-
-
-/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
-/// slot / to reg or any rematerialized load into ith operand of specified
-/// MI. If it is successul, MI is updated with the newly created MI and
-/// returns true.
-bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI,
- VirtRegMap &vrm, MachineInstr *DefMI,
- SlotIndex InstrIdx,
- SmallVector<unsigned, 2> &Ops,
- bool isSS, int Slot, unsigned Reg) {
- // If it is an implicit def instruction, just delete it.
- if (MI->isImplicitDef()) {
- RemoveMachineInstrFromMaps(MI);
- vrm.RemoveMachineInstrFromMaps(MI);
- MI->eraseFromParent();
- ++numFolds;
- return true;
- }
-
- // Filter the list of operand indexes that are to be folded. Abort if
- // any operand will prevent folding.
- unsigned MRInfo = 0;
- SmallVector<unsigned, 2> FoldOps;
- if (FilterFoldedOps(MI, Ops, MRInfo, FoldOps))
- return false;
-
- // The only time it's safe to fold into a two address instruction is when
- // it's folding reload and spill from / into a spill stack slot.
- if (DefMI && (MRInfo & VirtRegMap::isMod))
- return false;
-
- MachineInstr *fmi = isSS ? tii_->foldMemoryOperand(MI, FoldOps, Slot)
- : tii_->foldMemoryOperand(MI, FoldOps, DefMI);
- if (fmi) {
- // Remember this instruction uses the spill slot.
- if (isSS) vrm.addSpillSlotUse(Slot, fmi);
-
- // Attempt to fold the memory reference into the instruction. If
- // we can do this, we don't need to insert spill code.
- if (isSS && !mf_->getFrameInfo()->isImmutableObjectIndex(Slot))
- vrm.virtFolded(Reg, MI, fmi, (VirtRegMap::ModRef)MRInfo);
- vrm.transferSpillPts(MI, fmi);
- vrm.transferRestorePts(MI, fmi);
- vrm.transferEmergencySpills(MI, fmi);
- ReplaceMachineInstrInMaps(MI, fmi);
- MI->eraseFromParent();
- MI = fmi;
- ++numFolds;
- return true;
- }
- return false;
-}
-
-/// canFoldMemoryOperand - Returns true if the specified load / store
-/// folding is possible.
-bool LiveIntervals::canFoldMemoryOperand(MachineInstr *MI,
- SmallVector<unsigned, 2> &Ops,
- bool ReMat) const {
- // Filter the list of operand indexes that are to be folded. Abort if
- // any operand will prevent folding.
- unsigned MRInfo = 0;
- SmallVector<unsigned, 2> FoldOps;
- if (FilterFoldedOps(MI, Ops, MRInfo, FoldOps))
- return false;
-
- // It's only legal to remat for a use, not a def.
- if (ReMat && (MRInfo & VirtRegMap::isMod))
- return false;
-
- return tii_->canFoldMemoryOperand(MI, FoldOps);
-}
-
bool LiveIntervals::intervalIsInOneMBB(const LiveInterval &li) const {
LiveInterval::Ranges::const_iterator itr = li.ranges.begin();
return true;
}
-/// rewriteImplicitOps - Rewrite implicit use operands of MI (i.e. uses of
-/// interval on to-be re-materialized operands of MI) with new register.
-void LiveIntervals::rewriteImplicitOps(const LiveInterval &li,
- MachineInstr *MI, unsigned NewVReg,
- VirtRegMap &vrm) {
- // There is an implicit use. That means one of the other operand is
- // being remat'ed and the remat'ed instruction has li.reg as an
- // use operand. Make sure we rewrite that as well.
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg())
- continue;
- unsigned Reg = MO.getReg();
- if (!TargetRegisterInfo::isVirtualRegister(Reg))
- continue;
- if (!vrm.isReMaterialized(Reg))
- continue;
- MachineInstr *ReMatMI = vrm.getReMaterializedMI(Reg);
- MachineOperand *UseMO = ReMatMI->findRegisterUseOperand(li.reg);
- if (UseMO)
- UseMO->setReg(NewVReg);
- }
-}
-
-/// rewriteInstructionForSpills, rewriteInstructionsForSpills - Helper functions
-/// for addIntervalsForSpills to rewrite uses / defs for the given live range.
-bool LiveIntervals::
-rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
- bool TrySplit, SlotIndex index, SlotIndex end,
- MachineInstr *MI,
- MachineInstr *ReMatOrigDefMI, MachineInstr *ReMatDefMI,
- unsigned Slot, int LdSlot,
- bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
- VirtRegMap &vrm,
- const TargetRegisterClass* rc,
- SmallVector<int, 4> &ReMatIds,
- const MachineLoopInfo *loopInfo,
- unsigned &NewVReg, unsigned ImpUse, bool &HasDef, bool &HasUse,
- DenseMap<unsigned,unsigned> &MBBVRegsMap,
- std::vector<LiveInterval*> &NewLIs) {
- bool CanFold = false;
- RestartInstruction:
- for (unsigned i = 0; i != MI->getNumOperands(); ++i) {
- MachineOperand& mop = MI->getOperand(i);
- if (!mop.isReg())
- continue;
- unsigned Reg = mop.getReg();
- if (!TargetRegisterInfo::isVirtualRegister(Reg))
- continue;
- if (Reg != li.reg)
- continue;
-
- bool TryFold = !DefIsReMat;
- bool FoldSS = true; // Default behavior unless it's a remat.
- int FoldSlot = Slot;
- if (DefIsReMat) {
- // If this is the rematerializable definition MI itself and
- // all of its uses are rematerialized, simply delete it.
- if (MI == ReMatOrigDefMI && CanDelete) {
- DEBUG(dbgs() << "\t\t\t\tErasing re-materializable def: "
- << *MI << '\n');
- RemoveMachineInstrFromMaps(MI);
- vrm.RemoveMachineInstrFromMaps(MI);
- MI->eraseFromParent();
- break;
- }
-
- // If def for this use can't be rematerialized, then try folding.
- // If def is rematerializable and it's a load, also try folding.
- TryFold = !ReMatDefMI || (ReMatDefMI && (MI == ReMatOrigDefMI || isLoad));
- if (isLoad) {
- // Try fold loads (from stack slot, constant pool, etc.) into uses.
- FoldSS = isLoadSS;
- FoldSlot = LdSlot;
- }
- }
-
- // Scan all of the operands of this instruction rewriting operands
- // to use NewVReg instead of li.reg as appropriate. We do this for
- // two reasons:
- //
- // 1. If the instr reads the same spilled vreg multiple times, we
- // want to reuse the NewVReg.
- // 2. If the instr is a two-addr instruction, we are required to
- // keep the src/dst regs pinned.
- //
- // Keep track of whether we replace a use and/or def so that we can
- // create the spill interval with the appropriate range.
- SmallVector<unsigned, 2> Ops;
- tie(HasUse, HasDef) = MI->readsWritesVirtualRegister(Reg, &Ops);
-
- // Create a new virtual register for the spill interval.
- // Create the new register now so we can map the fold instruction
- // to the new register so when it is unfolded we get the correct
- // answer.
- bool CreatedNewVReg = false;
- if (NewVReg == 0) {
- NewVReg = mri_->createVirtualRegister(rc);
- vrm.grow();
- CreatedNewVReg = true;
-
- // The new virtual register should get the same allocation hints as the
- // old one.
- std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(Reg);
- if (Hint.first || Hint.second)
- mri_->setRegAllocationHint(NewVReg, Hint.first, Hint.second);
- }
-
- if (!TryFold)
- CanFold = false;
- else {
- // Do not fold load / store here if we are splitting. We'll find an
- // optimal point to insert a load / store later.
- if (!TrySplit) {
- if (tryFoldMemoryOperand(MI, vrm, ReMatDefMI, index,
- Ops, FoldSS, FoldSlot, NewVReg)) {
- // Folding the load/store can completely change the instruction in
- // unpredictable ways, rescan it from the beginning.
-
- if (FoldSS) {
- // We need to give the new vreg the same stack slot as the
- // spilled interval.
- vrm.assignVirt2StackSlot(NewVReg, FoldSlot);
- }
-
- HasUse = false;
- HasDef = false;
- CanFold = false;
- if (isNotInMIMap(MI))
- break;
- goto RestartInstruction;
- }
- } else {
- // We'll try to fold it later if it's profitable.
- CanFold = canFoldMemoryOperand(MI, Ops, DefIsReMat);
- }
- }
-
- mop.setReg(NewVReg);
- if (mop.isImplicit())
- rewriteImplicitOps(li, MI, NewVReg, vrm);
-
- // Reuse NewVReg for other reads.
- bool HasEarlyClobber = false;
- for (unsigned j = 0, e = Ops.size(); j != e; ++j) {
- MachineOperand &mopj = MI->getOperand(Ops[j]);
- mopj.setReg(NewVReg);
- if (mopj.isImplicit())
- rewriteImplicitOps(li, MI, NewVReg, vrm);
- if (mopj.isEarlyClobber())
- HasEarlyClobber = true;
- }
-
- if (CreatedNewVReg) {
- if (DefIsReMat) {
- vrm.setVirtIsReMaterialized(NewVReg, ReMatDefMI);
- if (ReMatIds[VNI->id] == VirtRegMap::MAX_STACK_SLOT) {
- // Each valnum may have its own remat id.
- ReMatIds[VNI->id] = vrm.assignVirtReMatId(NewVReg);
- } else {
- vrm.assignVirtReMatId(NewVReg, ReMatIds[VNI->id]);
- }
- if (!CanDelete || (HasUse && HasDef)) {
- // If this is a two-addr instruction then its use operands are
- // rematerializable but its def is not. It should be assigned a
- // stack slot.
- vrm.assignVirt2StackSlot(NewVReg, Slot);
- }
- } else {
- vrm.assignVirt2StackSlot(NewVReg, Slot);
- }
- } else if (HasUse && HasDef &&
- vrm.getStackSlot(NewVReg) == VirtRegMap::NO_STACK_SLOT) {
- // If this interval hasn't been assigned a stack slot (because earlier
- // def is a deleted remat def), do it now.
- assert(Slot != VirtRegMap::NO_STACK_SLOT);
- vrm.assignVirt2StackSlot(NewVReg, Slot);
- }
-
- // Re-matting an instruction with virtual register use. Add the
- // register as an implicit use on the use MI.
- if (DefIsReMat && ImpUse)
- MI->addOperand(MachineOperand::CreateReg(ImpUse, false, true));
-
- // Create a new register interval for this spill / remat.
- LiveInterval &nI = getOrCreateInterval(NewVReg);
- if (CreatedNewVReg) {
- NewLIs.push_back(&nI);
- MBBVRegsMap.insert(std::make_pair(MI->getParent()->getNumber(), NewVReg));
- if (TrySplit)
- vrm.setIsSplitFromReg(NewVReg, li.reg);
- }
-
- if (HasUse) {
- if (CreatedNewVReg) {
- LiveRange LR(index.getLoadIndex(), index.getDefIndex(),
- nI.getNextValue(SlotIndex(), 0, VNInfoAllocator));
- DEBUG(dbgs() << " +" << LR);
- nI.addRange(LR);
- } else {
- // Extend the split live interval to this def / use.
- SlotIndex End = index.getDefIndex();
- LiveRange LR(nI.ranges[nI.ranges.size()-1].end, End,
- nI.getValNumInfo(nI.getNumValNums()-1));
- DEBUG(dbgs() << " +" << LR);
- nI.addRange(LR);
- }
- }
- if (HasDef) {
- // An early clobber starts at the use slot, except for an early clobber
- // tied to a use operand (yes, that is a thing).
- LiveRange LR(HasEarlyClobber && !HasUse ?
- index.getUseIndex() : index.getDefIndex(),
- index.getStoreIndex(),
- nI.getNextValue(SlotIndex(), 0, VNInfoAllocator));
- DEBUG(dbgs() << " +" << LR);
- nI.addRange(LR);
- }
-
- DEBUG({
- dbgs() << "\t\t\t\tAdded new interval: ";
- nI.print(dbgs(), tri_);
- dbgs() << '\n';
- });
- }
- return CanFold;
-}
-bool LiveIntervals::anyKillInMBBAfterIdx(const LiveInterval &li,
- const VNInfo *VNI,
- MachineBasicBlock *MBB,
- SlotIndex Idx) const {
- return li.killedInRange(Idx.getNextSlot(), getMBBEndIdx(MBB));
-}
-
-/// RewriteInfo - Keep track of machine instrs that will be rewritten
-/// during spilling.
-namespace {
- struct RewriteInfo {
- SlotIndex Index;
- MachineInstr *MI;
- RewriteInfo(SlotIndex i, MachineInstr *mi) : Index(i), MI(mi) {}
- };
-
- struct RewriteInfoCompare {
- bool operator()(const RewriteInfo &LHS, const RewriteInfo &RHS) const {
- return LHS.Index < RHS.Index;
- }
- };
-}
-
-void LiveIntervals::
-rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
- LiveInterval::Ranges::const_iterator &I,
- MachineInstr *ReMatOrigDefMI, MachineInstr *ReMatDefMI,
- unsigned Slot, int LdSlot,
- bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
- VirtRegMap &vrm,
- const TargetRegisterClass* rc,
- SmallVector<int, 4> &ReMatIds,
- const MachineLoopInfo *loopInfo,
- BitVector &SpillMBBs,
- DenseMap<unsigned, std::vector<SRInfo> > &SpillIdxes,
- BitVector &RestoreMBBs,
- DenseMap<unsigned, std::vector<SRInfo> > &RestoreIdxes,
- DenseMap<unsigned,unsigned> &MBBVRegsMap,
- std::vector<LiveInterval*> &NewLIs) {
- bool AllCanFold = true;
- unsigned NewVReg = 0;
- SlotIndex start = I->start.getBaseIndex();
- SlotIndex end = I->end.getPrevSlot().getBaseIndex().getNextIndex();
-
- // First collect all the def / use in this live range that will be rewritten.
- // Make sure they are sorted according to instruction index.
- std::vector<RewriteInfo> RewriteMIs;
- for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(li.reg),
- re = mri_->reg_end(); ri != re; ) {
- MachineInstr *MI = &*ri;
- MachineOperand &O = ri.getOperand();
- ++ri;
- if (MI->isDebugValue()) {
- // Modify DBG_VALUE now that the value is in a spill slot.
- if (Slot != VirtRegMap::MAX_STACK_SLOT || isLoadSS) {
- uint64_t Offset = MI->getOperand(1).getImm();
- const MDNode *MDPtr = MI->getOperand(2).getMetadata();
- DebugLoc DL = MI->getDebugLoc();
- int FI = isLoadSS ? LdSlot : (int)Slot;
- if (MachineInstr *NewDV = tii_->emitFrameIndexDebugValue(*mf_, FI,
- Offset, MDPtr, DL)) {
- DEBUG(dbgs() << "Modifying debug info due to spill:" << "\t" << *MI);
- ReplaceMachineInstrInMaps(MI, NewDV);
- MachineBasicBlock *MBB = MI->getParent();
- MBB->insert(MBB->erase(MI), NewDV);
- continue;
- }
- }
-
- DEBUG(dbgs() << "Removing debug info due to spill:" << "\t" << *MI);
- RemoveMachineInstrFromMaps(MI);
- vrm.RemoveMachineInstrFromMaps(MI);
- MI->eraseFromParent();
- continue;
- }
- assert(!(O.isImplicit() && O.isUse()) &&
- "Spilling register that's used as implicit use?");
- SlotIndex index = getInstructionIndex(MI);
- if (index < start || index >= end)
- continue;
-
- if (O.isUndef())
- // Must be defined by an implicit def. It should not be spilled. Note,
- // this is for correctness reason. e.g.
- // 8 %reg1024<def> = IMPLICIT_DEF
- // 12 %reg1024<def> = INSERT_SUBREG %reg1024<kill>, %reg1025, 2
- // The live range [12, 14) are not part of the r1024 live interval since
- // it's defined by an implicit def. It will not conflicts with live
- // interval of r1025. Now suppose both registers are spilled, you can
- // easily see a situation where both registers are reloaded before
- // the INSERT_SUBREG and both target registers that would overlap.
- continue;
- RewriteMIs.push_back(RewriteInfo(index, MI));
- }
- std::sort(RewriteMIs.begin(), RewriteMIs.end(), RewriteInfoCompare());
-
- unsigned ImpUse = DefIsReMat ? getReMatImplicitUse(li, ReMatDefMI) : 0;
- // Now rewrite the defs and uses.
- for (unsigned i = 0, e = RewriteMIs.size(); i != e; ) {
- RewriteInfo &rwi = RewriteMIs[i];
- ++i;
- SlotIndex index = rwi.Index;
- MachineInstr *MI = rwi.MI;
- // If MI def and/or use the same register multiple times, then there
- // are multiple entries.
- while (i != e && RewriteMIs[i].MI == MI) {
- assert(RewriteMIs[i].Index == index);
- ++i;
- }
- MachineBasicBlock *MBB = MI->getParent();
-
- if (ImpUse && MI != ReMatDefMI) {
- // Re-matting an instruction with virtual register use. Prevent interval
- // from being spilled.
- getInterval(ImpUse).markNotSpillable();
- }
-
- unsigned MBBId = MBB->getNumber();
- unsigned ThisVReg = 0;
- if (TrySplit) {
- DenseMap<unsigned,unsigned>::iterator NVI = MBBVRegsMap.find(MBBId);
- if (NVI != MBBVRegsMap.end()) {
- ThisVReg = NVI->second;
- // One common case:
- // x = use
- // ...
- // ...
- // def = ...
- // = use
- // It's better to start a new interval to avoid artifically
- // extend the new interval.
- if (MI->readsWritesVirtualRegister(li.reg) ==
- std::make_pair(false,true)) {
- MBBVRegsMap.erase(MBB->getNumber());
- ThisVReg = 0;
- }
- }
- }
-
- bool IsNew = ThisVReg == 0;
- if (IsNew) {
- // This ends the previous live interval. If all of its def / use
- // can be folded, give it a low spill weight.
- if (NewVReg && TrySplit && AllCanFold) {
- LiveInterval &nI = getOrCreateInterval(NewVReg);
- nI.weight /= 10.0F;
- }
- AllCanFold = true;
- }
- NewVReg = ThisVReg;
-
- bool HasDef = false;
- bool HasUse = false;
- bool CanFold = rewriteInstructionForSpills(li, I->valno, TrySplit,
- index, end, MI, ReMatOrigDefMI, ReMatDefMI,
- Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
- CanDelete, vrm, rc, ReMatIds, loopInfo, NewVReg,
- ImpUse, HasDef, HasUse, MBBVRegsMap, NewLIs);
- if (!HasDef && !HasUse)
- continue;
-
- AllCanFold &= CanFold;
-
- // Update weight of spill interval.
- LiveInterval &nI = getOrCreateInterval(NewVReg);
- if (!TrySplit) {
- // The spill weight is now infinity as it cannot be spilled again.
- nI.markNotSpillable();
- continue;
- }
-
- // Keep track of the last def and first use in each MBB.
- if (HasDef) {
- if (MI != ReMatOrigDefMI || !CanDelete) {
- bool HasKill = false;
- if (!HasUse)
- HasKill = anyKillInMBBAfterIdx(li, I->valno, MBB, index.getDefIndex());
- else {
- // If this is a two-address code, then this index starts a new VNInfo.
- const VNInfo *VNI = li.findDefinedVNInfoForRegInt(index.getDefIndex());
- if (VNI)
- HasKill = anyKillInMBBAfterIdx(li, VNI, MBB, index.getDefIndex());
- }
- DenseMap<unsigned, std::vector<SRInfo> >::iterator SII =
- SpillIdxes.find(MBBId);
- if (!HasKill) {
- if (SII == SpillIdxes.end()) {
- std::vector<SRInfo> S;
- S.push_back(SRInfo(index, NewVReg, true));
- SpillIdxes.insert(std::make_pair(MBBId, S));
- } else if (SII->second.back().vreg != NewVReg) {
- SII->second.push_back(SRInfo(index, NewVReg, true));
- } else if (index > SII->second.back().index) {
- // If there is an earlier def and this is a two-address
- // instruction, then it's not possible to fold the store (which
- // would also fold the load).
- SRInfo &Info = SII->second.back();
- Info.index = index;
- Info.canFold = !HasUse;
- }
- SpillMBBs.set(MBBId);
- } else if (SII != SpillIdxes.end() &&
- SII->second.back().vreg == NewVReg &&
- index > SII->second.back().index) {
- // There is an earlier def that's not killed (must be two-address).
- // The spill is no longer needed.
- SII->second.pop_back();
- if (SII->second.empty()) {
- SpillIdxes.erase(MBBId);
- SpillMBBs.reset(MBBId);
- }
- }
- }
- }
-
- if (HasUse) {
- DenseMap<unsigned, std::vector<SRInfo> >::iterator SII =
- SpillIdxes.find(MBBId);
- if (SII != SpillIdxes.end() &&
- SII->second.back().vreg == NewVReg &&
- index > SII->second.back().index)
- // Use(s) following the last def, it's not safe to fold the spill.
- SII->second.back().canFold = false;
- DenseMap<unsigned, std::vector<SRInfo> >::iterator RII =
- RestoreIdxes.find(MBBId);
- if (RII != RestoreIdxes.end() && RII->second.back().vreg == NewVReg)
- // If we are splitting live intervals, only fold if it's the first
- // use and there isn't another use later in the MBB.
- RII->second.back().canFold = false;
- else if (IsNew) {
- // Only need a reload if there isn't an earlier def / use.
- if (RII == RestoreIdxes.end()) {
- std::vector<SRInfo> Infos;
- Infos.push_back(SRInfo(index, NewVReg, true));
- RestoreIdxes.insert(std::make_pair(MBBId, Infos));
- } else {
- RII->second.push_back(SRInfo(index, NewVReg, true));
- }
- RestoreMBBs.set(MBBId);
- }
- }
-
- // Update spill weight.
- unsigned loopDepth = loopInfo->getLoopDepth(MBB);
- nI.weight += getSpillWeight(HasDef, HasUse, loopDepth);
- }
-
- if (NewVReg && TrySplit && AllCanFold) {
- // If all of its def / use can be folded, give it a low spill weight.
- LiveInterval &nI = getOrCreateInterval(NewVReg);
- nI.weight /= 10.0F;
- }
-}
-
-bool LiveIntervals::alsoFoldARestore(int Id, SlotIndex index,
- unsigned vr, BitVector &RestoreMBBs,
- DenseMap<unsigned,std::vector<SRInfo> > &RestoreIdxes) {
- if (!RestoreMBBs[Id])
- return false;
- std::vector<SRInfo> &Restores = RestoreIdxes[Id];
- for (unsigned i = 0, e = Restores.size(); i != e; ++i)
- if (Restores[i].index == index &&
- Restores[i].vreg == vr &&
- Restores[i].canFold)
- return true;
- return false;
-}
-
-void LiveIntervals::eraseRestoreInfo(int Id, SlotIndex index,
- unsigned vr, BitVector &RestoreMBBs,
- DenseMap<unsigned,std::vector<SRInfo> > &RestoreIdxes) {
- if (!RestoreMBBs[Id])
- return;
- std::vector<SRInfo> &Restores = RestoreIdxes[Id];
- for (unsigned i = 0, e = Restores.size(); i != e; ++i)
- if (Restores[i].index == index && Restores[i].vreg)
- Restores[i].index = SlotIndex();
-}
-
-/// handleSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
-/// spilled and create empty intervals for their uses.
-void
-LiveIntervals::handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
- const TargetRegisterClass* rc,
- std::vector<LiveInterval*> &NewLIs) {
- for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(li.reg),
- re = mri_->reg_end(); ri != re; ) {
- MachineOperand &O = ri.getOperand();
- MachineInstr *MI = &*ri;
- ++ri;
- if (MI->isDebugValue()) {
- // Remove debug info for now.
- O.setReg(0U);
- DEBUG(dbgs() << "Removing debug info due to spill:" << "\t" << *MI);
- continue;
- }
- if (O.isDef()) {
- assert(MI->isImplicitDef() &&
- "Register def was not rewritten?");
- RemoveMachineInstrFromMaps(MI);
- vrm.RemoveMachineInstrFromMaps(MI);
- MI->eraseFromParent();
- } else {
- // This must be an use of an implicit_def so it's not part of the live
- // interval. Create a new empty live interval for it.
- // FIXME: Can we simply erase some of the instructions? e.g. Stores?
- unsigned NewVReg = mri_->createVirtualRegister(rc);
- vrm.grow();
- vrm.setIsImplicitlyDefined(NewVReg);
- NewLIs.push_back(&getOrCreateInterval(NewVReg));
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (MO.isReg() && MO.getReg() == li.reg) {
- MO.setReg(NewVReg);
- MO.setIsUndef();
- }
- }
- }
- }
-}
-
float
LiveIntervals::getSpillWeight(bool isDef, bool isUse, unsigned loopDepth) {
// Limit the loop depth ridiculousness.
// overflow a float. This expression behaves like 10^d for small d, but is
// more tempered for large d. At d=200 we get 6.7e33 which leaves a bit of
// headroom before overflow.
- float lc = std::pow(1 + (100.0f / (loopDepth+10)), (float)loopDepth);
+ // By the way, powf() might be unavailable here. For consistency,
+ // We may take pow(double,double).
+ float lc = std::pow(1 + (100.0 / (loopDepth + 10)), (double)loopDepth);
return (isDef + isUse) * lc;
}
-void
-LiveIntervals::normalizeSpillWeights(std::vector<LiveInterval*> &NewLIs) {
- for (unsigned i = 0, e = NewLIs.size(); i != e; ++i)
- normalizeSpillWeight(*NewLIs[i]);
-}
-
-std::vector<LiveInterval*> LiveIntervals::
-addIntervalsForSpills(const LiveInterval &li,
- const SmallVectorImpl<LiveInterval*> &SpillIs,
- const MachineLoopInfo *loopInfo, VirtRegMap &vrm) {
- assert(li.isSpillable() && "attempt to spill already spilled interval!");
-
- DEBUG({
- dbgs() << "\t\t\t\tadding intervals for spills for interval: ";
- li.print(dbgs(), tri_);
- dbgs() << '\n';
- });
-
- // Each bit specify whether a spill is required in the MBB.
- BitVector SpillMBBs(mf_->getNumBlockIDs());
- DenseMap<unsigned, std::vector<SRInfo> > SpillIdxes;
- BitVector RestoreMBBs(mf_->getNumBlockIDs());
- DenseMap<unsigned, std::vector<SRInfo> > RestoreIdxes;
- DenseMap<unsigned,unsigned> MBBVRegsMap;
- std::vector<LiveInterval*> NewLIs;
- const TargetRegisterClass* rc = mri_->getRegClass(li.reg);
-
- unsigned NumValNums = li.getNumValNums();
- SmallVector<MachineInstr*, 4> ReMatDefs;
- ReMatDefs.resize(NumValNums, NULL);
- SmallVector<MachineInstr*, 4> ReMatOrigDefs;
- ReMatOrigDefs.resize(NumValNums, NULL);
- SmallVector<int, 4> ReMatIds;
- ReMatIds.resize(NumValNums, VirtRegMap::MAX_STACK_SLOT);
- BitVector ReMatDelete(NumValNums);
- unsigned Slot = VirtRegMap::MAX_STACK_SLOT;
-
- // Spilling a split live interval. It cannot be split any further. Also,
- // it's also guaranteed to be a single val# / range interval.
- if (vrm.getPreSplitReg(li.reg)) {
- vrm.setIsSplitFromReg(li.reg, 0);
- // Unset the split kill marker on the last use.
- SlotIndex KillIdx = vrm.getKillPoint(li.reg);
- if (KillIdx != SlotIndex()) {
- MachineInstr *KillMI = getInstructionFromIndex(KillIdx);
- assert(KillMI && "Last use disappeared?");
- int KillOp = KillMI->findRegisterUseOperandIdx(li.reg, true);
- assert(KillOp != -1 && "Last use disappeared?");
- KillMI->getOperand(KillOp).setIsKill(false);
- }
- vrm.removeKillPoint(li.reg);
- bool DefIsReMat = vrm.isReMaterialized(li.reg);
- Slot = vrm.getStackSlot(li.reg);
- assert(Slot != VirtRegMap::MAX_STACK_SLOT);
- MachineInstr *ReMatDefMI = DefIsReMat ?
- vrm.getReMaterializedMI(li.reg) : NULL;
- int LdSlot = 0;
- bool isLoadSS = DefIsReMat && tii_->isLoadFromStackSlot(ReMatDefMI, LdSlot);
- bool isLoad = isLoadSS ||
- (DefIsReMat && (ReMatDefMI->getDesc().canFoldAsLoad()));
- bool IsFirstRange = true;
- for (LiveInterval::Ranges::const_iterator
- I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
- // If this is a split live interval with multiple ranges, it means there
- // are two-address instructions that re-defined the value. Only the
- // first def can be rematerialized!
- if (IsFirstRange) {
- // Note ReMatOrigDefMI has already been deleted.
- rewriteInstructionsForSpills(li, false, I, NULL, ReMatDefMI,
- Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
- false, vrm, rc, ReMatIds, loopInfo,
- SpillMBBs, SpillIdxes, RestoreMBBs, RestoreIdxes,
- MBBVRegsMap, NewLIs);
- } else {
- rewriteInstructionsForSpills(li, false, I, NULL, 0,
- Slot, 0, false, false, false,
- false, vrm, rc, ReMatIds, loopInfo,
- SpillMBBs, SpillIdxes, RestoreMBBs, RestoreIdxes,
- MBBVRegsMap, NewLIs);
- }
- IsFirstRange = false;
- }
-
- handleSpilledImpDefs(li, vrm, rc, NewLIs);
- normalizeSpillWeights(NewLIs);
- return NewLIs;
- }
-
- bool TrySplit = !intervalIsInOneMBB(li);
- if (TrySplit)
- ++numSplits;
- bool NeedStackSlot = false;
- for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
- i != e; ++i) {
- const VNInfo *VNI = *i;
- unsigned VN = VNI->id;
- if (VNI->isUnused())
- continue; // Dead val#.
- // Is the def for the val# rematerializable?
- MachineInstr *ReMatDefMI = getInstructionFromIndex(VNI->def);
- bool dummy;
- if (ReMatDefMI && isReMaterializable(li, VNI, ReMatDefMI, SpillIs, dummy)) {
- // Remember how to remat the def of this val#.
- ReMatOrigDefs[VN] = ReMatDefMI;
- // Original def may be modified so we have to make a copy here.
- MachineInstr *Clone = mf_->CloneMachineInstr(ReMatDefMI);
- CloneMIs.push_back(Clone);
- ReMatDefs[VN] = Clone;
-
- bool CanDelete = true;
- if (VNI->hasPHIKill()) {
- // A kill is a phi node, not all of its uses can be rematerialized.
- // It must not be deleted.
- CanDelete = false;
- // Need a stack slot if there is any live range where uses cannot be
- // rematerialized.
- NeedStackSlot = true;
- }
- if (CanDelete)
- ReMatDelete.set(VN);
- } else {
- // Need a stack slot if there is any live range where uses cannot be
- // rematerialized.
- NeedStackSlot = true;
- }
- }
-
- // One stack slot per live interval.
- if (NeedStackSlot && vrm.getPreSplitReg(li.reg) == 0) {
- if (vrm.getStackSlot(li.reg) == VirtRegMap::NO_STACK_SLOT)
- Slot = vrm.assignVirt2StackSlot(li.reg);
-
- // This case only occurs when the prealloc splitter has already assigned
- // a stack slot to this vreg.
- else
- Slot = vrm.getStackSlot(li.reg);
- }
-
- // Create new intervals and rewrite defs and uses.
- for (LiveInterval::Ranges::const_iterator
- I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
- MachineInstr *ReMatDefMI = ReMatDefs[I->valno->id];
- MachineInstr *ReMatOrigDefMI = ReMatOrigDefs[I->valno->id];
- bool DefIsReMat = ReMatDefMI != NULL;
- bool CanDelete = ReMatDelete[I->valno->id];
- int LdSlot = 0;
- bool isLoadSS = DefIsReMat && tii_->isLoadFromStackSlot(ReMatDefMI, LdSlot);
- bool isLoad = isLoadSS ||
- (DefIsReMat && ReMatDefMI->getDesc().canFoldAsLoad());
- rewriteInstructionsForSpills(li, TrySplit, I, ReMatOrigDefMI, ReMatDefMI,
- Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
- CanDelete, vrm, rc, ReMatIds, loopInfo,
- SpillMBBs, SpillIdxes, RestoreMBBs, RestoreIdxes,
- MBBVRegsMap, NewLIs);
- }
-
- // Insert spills / restores if we are splitting.
- if (!TrySplit) {
- handleSpilledImpDefs(li, vrm, rc, NewLIs);
- normalizeSpillWeights(NewLIs);
- return NewLIs;
- }
-
- SmallPtrSet<LiveInterval*, 4> AddedKill;
- SmallVector<unsigned, 2> Ops;
- if (NeedStackSlot) {
- int Id = SpillMBBs.find_first();
- while (Id != -1) {
- std::vector<SRInfo> &spills = SpillIdxes[Id];
- for (unsigned i = 0, e = spills.size(); i != e; ++i) {
- SlotIndex index = spills[i].index;
- unsigned VReg = spills[i].vreg;
- LiveInterval &nI = getOrCreateInterval(VReg);
- bool isReMat = vrm.isReMaterialized(VReg);
- MachineInstr *MI = getInstructionFromIndex(index);
- bool CanFold = false;
- bool FoundUse = false;
- Ops.clear();
- if (spills[i].canFold) {
- CanFold = true;
- for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) {
- MachineOperand &MO = MI->getOperand(j);
- if (!MO.isReg() || MO.getReg() != VReg)
- continue;
-
- Ops.push_back(j);
- if (MO.isDef())
- continue;
- if (isReMat ||
- (!FoundUse && !alsoFoldARestore(Id, index, VReg,
- RestoreMBBs, RestoreIdxes))) {
- // MI has two-address uses of the same register. If the use
- // isn't the first and only use in the BB, then we can't fold
- // it. FIXME: Move this to rewriteInstructionsForSpills.
- CanFold = false;
- break;
- }
- FoundUse = true;
- }
- }
- // Fold the store into the def if possible.
- bool Folded = false;
- if (CanFold && !Ops.empty()) {
- if (tryFoldMemoryOperand(MI, vrm, NULL, index, Ops, true, Slot,VReg)){
- Folded = true;
- if (FoundUse) {
- // Also folded uses, do not issue a load.
- eraseRestoreInfo(Id, index, VReg, RestoreMBBs, RestoreIdxes);
- nI.removeRange(index.getLoadIndex(), index.getDefIndex());
- }
- nI.removeRange(index.getDefIndex(), index.getStoreIndex());
- }
- }
-
- // Otherwise tell the spiller to issue a spill.
- if (!Folded) {
- LiveRange *LR = &nI.ranges[nI.ranges.size()-1];
- bool isKill = LR->end == index.getStoreIndex();
- if (!MI->registerDefIsDead(nI.reg))
- // No need to spill a dead def.
- vrm.addSpillPoint(VReg, isKill, MI);
- if (isKill)
- AddedKill.insert(&nI);
- }
- }
- Id = SpillMBBs.find_next(Id);
- }
- }
-
- int Id = RestoreMBBs.find_first();
- while (Id != -1) {
- std::vector<SRInfo> &restores = RestoreIdxes[Id];
- for (unsigned i = 0, e = restores.size(); i != e; ++i) {
- SlotIndex index = restores[i].index;
- if (index == SlotIndex())
- continue;
- unsigned VReg = restores[i].vreg;
- LiveInterval &nI = getOrCreateInterval(VReg);
- bool isReMat = vrm.isReMaterialized(VReg);
- MachineInstr *MI = getInstructionFromIndex(index);
- bool CanFold = false;
- Ops.clear();
- if (restores[i].canFold) {
- CanFold = true;
- for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) {
- MachineOperand &MO = MI->getOperand(j);
- if (!MO.isReg() || MO.getReg() != VReg)
- continue;
-
- if (MO.isDef()) {
- // If this restore were to be folded, it would have been folded
- // already.
- CanFold = false;
- break;
- }
- Ops.push_back(j);
- }
- }
-
- // Fold the load into the use if possible.
- bool Folded = false;
- if (CanFold && !Ops.empty()) {
- if (!isReMat)
- Folded = tryFoldMemoryOperand(MI, vrm, NULL,index,Ops,true,Slot,VReg);
- else {
- MachineInstr *ReMatDefMI = vrm.getReMaterializedMI(VReg);
- int LdSlot = 0;
- bool isLoadSS = tii_->isLoadFromStackSlot(ReMatDefMI, LdSlot);
- // If the rematerializable def is a load, also try to fold it.
- if (isLoadSS || ReMatDefMI->getDesc().canFoldAsLoad())
- Folded = tryFoldMemoryOperand(MI, vrm, ReMatDefMI, index,
- Ops, isLoadSS, LdSlot, VReg);
- if (!Folded) {
- unsigned ImpUse = getReMatImplicitUse(li, ReMatDefMI);
- if (ImpUse) {
- // Re-matting an instruction with virtual register use. Add the
- // register as an implicit use on the use MI and mark the register
- // interval as unspillable.
- LiveInterval &ImpLi = getInterval(ImpUse);
- ImpLi.markNotSpillable();
- MI->addOperand(MachineOperand::CreateReg(ImpUse, false, true));
- }
- }
- }
- }
- // If folding is not possible / failed, then tell the spiller to issue a
- // load / rematerialization for us.
- if (Folded)
- nI.removeRange(index.getLoadIndex(), index.getDefIndex());
- else
- vrm.addRestorePoint(VReg, MI);
- }
- Id = RestoreMBBs.find_next(Id);
- }
-
- // Finalize intervals: add kills, finalize spill weights, and filter out
- // dead intervals.
- std::vector<LiveInterval*> RetNewLIs;
- for (unsigned i = 0, e = NewLIs.size(); i != e; ++i) {
- LiveInterval *LI = NewLIs[i];
- if (!LI->empty()) {
- if (!AddedKill.count(LI)) {
- LiveRange *LR = &LI->ranges[LI->ranges.size()-1];
- SlotIndex LastUseIdx = LR->end.getBaseIndex();
- MachineInstr *LastUse = getInstructionFromIndex(LastUseIdx);
- int UseIdx = LastUse->findRegisterUseOperandIdx(LI->reg, false);
- assert(UseIdx != -1);
- if (!LastUse->isRegTiedToDefOperand(UseIdx)) {
- LastUse->getOperand(UseIdx).setIsKill();
- vrm.addKillPoint(LI->reg, LastUseIdx);
- }
- }
- RetNewLIs.push_back(LI);
- }
- }
-
- handleSpilledImpDefs(li, vrm, rc, RetNewLIs);
- normalizeSpillWeights(RetNewLIs);
- return RetNewLIs;
-}
-
-/// hasAllocatableSuperReg - Return true if the specified physical register has
-/// any super register that's allocatable.
-bool LiveIntervals::hasAllocatableSuperReg(unsigned Reg) const {
- for (const unsigned* AS = tri_->getSuperRegisters(Reg); *AS; ++AS)
- if (allocatableRegs_[*AS] && hasInterval(*AS))
- return true;
- return false;
-}
-
-/// getRepresentativeReg - Find the largest super register of the specified
-/// physical register.
-unsigned LiveIntervals::getRepresentativeReg(unsigned Reg) const {
- // Find the largest super-register that is allocatable.
- unsigned BestReg = Reg;
- for (const unsigned* AS = tri_->getSuperRegisters(Reg); *AS; ++AS) {
- unsigned SuperReg = *AS;
- if (!hasAllocatableSuperReg(SuperReg) && hasInterval(SuperReg)) {
- BestReg = SuperReg;
- break;
- }
- }
- return BestReg;
-}
-
-/// getNumConflictsWithPhysReg - Return the number of uses and defs of the
-/// specified interval that conflicts with the specified physical register.
-unsigned LiveIntervals::getNumConflictsWithPhysReg(const LiveInterval &li,
- unsigned PhysReg) const {
- unsigned NumConflicts = 0;
- const LiveInterval &pli = getInterval(getRepresentativeReg(PhysReg));
- for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(li.reg),
- E = mri_->reg_end(); I != E; ++I) {
- MachineOperand &O = I.getOperand();
- MachineInstr *MI = O.getParent();
- if (MI->isDebugValue())
- continue;
- SlotIndex Index = getInstructionIndex(MI);
- if (pli.liveAt(Index))
- ++NumConflicts;
- }
- return NumConflicts;
-}
-
-/// spillPhysRegAroundRegDefsUses - Spill the specified physical register
-/// around all defs and uses of the specified interval. Return true if it
-/// was able to cut its interval.
-bool LiveIntervals::spillPhysRegAroundRegDefsUses(const LiveInterval &li,
- unsigned PhysReg, VirtRegMap &vrm) {
- unsigned SpillReg = getRepresentativeReg(PhysReg);
-
- DEBUG(dbgs() << "spillPhysRegAroundRegDefsUses " << tri_->getName(PhysReg)
- << " represented by " << tri_->getName(SpillReg) << '\n');
-
- for (const unsigned *AS = tri_->getAliasSet(PhysReg); *AS; ++AS)
- // If there are registers which alias PhysReg, but which are not a
- // sub-register of the chosen representative super register. Assert
- // since we can't handle it yet.
- assert(*AS == SpillReg || !allocatableRegs_[*AS] || !hasInterval(*AS) ||
- tri_->isSuperRegister(*AS, SpillReg));
-
- bool Cut = false;
- SmallVector<unsigned, 4> PRegs;
- if (hasInterval(SpillReg))
- PRegs.push_back(SpillReg);
- for (const unsigned *SR = tri_->getSubRegisters(SpillReg); *SR; ++SR)
- if (hasInterval(*SR))
- PRegs.push_back(*SR);
-
- DEBUG({
- dbgs() << "Trying to spill:";
- for (unsigned i = 0, e = PRegs.size(); i != e; ++i)
- dbgs() << ' ' << tri_->getName(PRegs[i]);
- dbgs() << '\n';
- });
-
- SmallPtrSet<MachineInstr*, 8> SeenMIs;
- for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(li.reg),
- E = mri_->reg_end(); I != E; ++I) {
- MachineOperand &O = I.getOperand();
- MachineInstr *MI = O.getParent();
- if (MI->isDebugValue() || SeenMIs.count(MI))
- continue;
- SeenMIs.insert(MI);
- SlotIndex Index = getInstructionIndex(MI);
- bool LiveReg = false;
- for (unsigned i = 0, e = PRegs.size(); i != e; ++i) {
- unsigned PReg = PRegs[i];
- LiveInterval &pli = getInterval(PReg);
- if (!pli.liveAt(Index))
- continue;
- LiveReg = true;
- SlotIndex StartIdx = Index.getLoadIndex();
- SlotIndex EndIdx = Index.getNextIndex().getBaseIndex();
- if (!pli.isInOneLiveRange(StartIdx, EndIdx)) {
- std::string msg;
- raw_string_ostream Msg(msg);
- Msg << "Ran out of registers during register allocation!";
- if (MI->isInlineAsm()) {
- Msg << "\nPlease check your inline asm statement for invalid "
- << "constraints:\n";
- MI->print(Msg, tm_);
- }
- report_fatal_error(Msg.str());
- }
- pli.removeRange(StartIdx, EndIdx);
- LiveReg = true;
- }
- if (!LiveReg)
- continue;
- DEBUG(dbgs() << "Emergency spill around " << Index << '\t' << *MI);
- vrm.addEmergencySpill(SpillReg, MI);
- Cut = true;
- }
- return Cut;
-}
-
LiveRange LiveIntervals::addLiveRangeToEndOfBlock(unsigned reg,
MachineInstr* startInst) {
LiveInterval& Interval = getOrCreateInterval(reg);
VNInfo* VN = Interval.getNextValue(
- SlotIndex(getInstructionIndex(startInst).getDefIndex()),
+ SlotIndex(getInstructionIndex(startInst).getRegSlot()),
startInst, getVNInfoAllocator());
VN->setHasPHIKill(true);
LiveRange LR(
- SlotIndex(getInstructionIndex(startInst).getDefIndex()),
+ SlotIndex(getInstructionIndex(startInst).getRegSlot()),
getMBBEndIdx(startInst->getParent()), VN);
Interval.addRange(LR);
projects / oota-llvm.git / blobdiff