RegAssign.clear();
Values.clear();
- // We don't need to clear LiveOutCache, only LiveOutSeen entries are read.
- LiveOutSeen.clear();
+ // Reset the LiveRangeCalc instances needed for this spill mode.
+ LRCalc[0].reset(&VRM.getMachineFunction());
+ if (SpillMode)
+ LRCalc[1].reset(&VRM.getMachineFunction());
// We don't need an AliasAnalysis since we will only be performing
// cheap-as-a-copy remats anyway.
// extendRange - Extend the live range to reach Idx.
// Potentially create phi-def values.
void SplitEditor::extendRange(unsigned RegIdx, SlotIndex Idx) {
- assert(Idx.isValid() && "Invalid SlotIndex");
- MachineBasicBlock *IdxMBB = LIS.getMBBFromIndex(Idx);
- assert(IdxMBB && "No MBB at Idx");
- LiveInterval *LI = Edit->get(RegIdx);
-
- // Is there a def in the same MBB we can extend?
- if (LI->extendInBlock(LIS.getMBBStartIdx(IdxMBB), Idx))
- return;
-
- // Now for the fun part. We know that ParentVNI potentially has multiple defs,
- // and we may need to create even more phi-defs to preserve VNInfo SSA form.
- // Perform a search for all predecessor blocks where we know the dominating
- // VNInfo.
- VNInfo *VNI = findReachingDefs(LI, IdxMBB, Idx.getNextSlot());
-
- // When there were multiple different values, we may need new PHIs.
- if (!VNI)
- return updateSSA();
-
- // Poor man's SSA update for the single-value case.
- LiveOutPair LOP(VNI, MDT[LIS.getMBBFromIndex(VNI->def)]);
- for (SmallVectorImpl<LiveInBlock>::iterator I = LiveInBlocks.begin(),
- E = LiveInBlocks.end(); I != E; ++I) {
- MachineBasicBlock *MBB = I->DomNode->getBlock();
- SlotIndex Start = LIS.getMBBStartIdx(MBB);
- if (I->Kill.isValid())
- LI->addRange(LiveRange(Start, I->Kill, VNI));
- else {
- LiveOutCache[MBB] = LOP;
- LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
- }
- }
-}
-
-/// findReachingDefs - Search the CFG for known live-out values.
-/// Add required live-in blocks to LiveInBlocks.
-VNInfo *SplitEditor::findReachingDefs(LiveInterval *LI,
- MachineBasicBlock *KillMBB,
- SlotIndex Kill) {
- // Initialize the live-out cache the first time it is needed.
- if (LiveOutSeen.empty()) {
- unsigned N = VRM.getMachineFunction().getNumBlockIDs();
- LiveOutSeen.resize(N);
- LiveOutCache.resize(N);
- }
-
- // Blocks where LI should be live-in.
- SmallVector<MachineBasicBlock*, 16> WorkList(1, KillMBB);
-
- // Remember if we have seen more than one value.
- bool UniqueVNI = true;
- VNInfo *TheVNI = 0;
-
- // Using LiveOutCache as a visited set, perform a BFS for all reaching defs.
- for (unsigned i = 0; i != WorkList.size(); ++i) {
- MachineBasicBlock *MBB = WorkList[i];
- assert(!MBB->pred_empty() && "Value live-in to entry block?");
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- MachineBasicBlock *Pred = *PI;
- LiveOutPair &LOP = LiveOutCache[Pred];
-
- // Is this a known live-out block?
- if (LiveOutSeen.test(Pred->getNumber())) {
- if (VNInfo *VNI = LOP.first) {
- if (TheVNI && TheVNI != VNI)
- UniqueVNI = false;
- TheVNI = VNI;
- }
- continue;
- }
-
- // First time. LOP is garbage and must be cleared below.
- LiveOutSeen.set(Pred->getNumber());
-
- // Does Pred provide a live-out value?
- SlotIndex Start, Last;
- tie(Start, Last) = LIS.getSlotIndexes()->getMBBRange(Pred);
- Last = Last.getPrevSlot();
- VNInfo *VNI = LI->extendInBlock(Start, Last);
- LOP.first = VNI;
- if (VNI) {
- LOP.second = MDT[LIS.getMBBFromIndex(VNI->def)];
- if (TheVNI && TheVNI != VNI)
- UniqueVNI = false;
- TheVNI = VNI;
- continue;
- }
- LOP.second = 0;
-
- // No, we need a live-in value for Pred as well
- if (Pred != KillMBB)
- WorkList.push_back(Pred);
- else
- // Loopback to KillMBB, so value is really live through.
- Kill = SlotIndex();
- }
- }
-
- // Transfer WorkList to LiveInBlocks in reverse order.
- // This ordering works best with updateSSA().
- LiveInBlocks.clear();
- LiveInBlocks.reserve(WorkList.size());
- while(!WorkList.empty())
- LiveInBlocks.push_back(MDT[WorkList.pop_back_val()]);
-
- // The kill block may not be live-through.
- assert(LiveInBlocks.back().DomNode->getBlock() == KillMBB);
- LiveInBlocks.back().Kill = Kill;
-
- return UniqueVNI ? TheVNI : 0;
-}
-
-void SplitEditor::updateSSA() {
- // This is essentially the same iterative algorithm that SSAUpdater uses,
- // except we already have a dominator tree, so we don't have to recompute it.
- unsigned Changes;
- do {
- Changes = 0;
- // Propagate live-out values down the dominator tree, inserting phi-defs
- // when necessary.
- for (SmallVectorImpl<LiveInBlock>::iterator I = LiveInBlocks.begin(),
- E = LiveInBlocks.end(); I != E; ++I) {
- MachineDomTreeNode *Node = I->DomNode;
- // Skip block if the live-in value has already been determined.
- if (!Node)
- continue;
- MachineBasicBlock *MBB = Node->getBlock();
- MachineDomTreeNode *IDom = Node->getIDom();
- LiveOutPair IDomValue;
-
- // We need a live-in value to a block with no immediate dominator?
- // This is probably an unreachable block that has survived somehow.
- bool needPHI = !IDom || !LiveOutSeen.test(IDom->getBlock()->getNumber());
-
- // IDom dominates all of our predecessors, but it may not be their
- // immediate dominator. Check if any of them have live-out values that are
- // properly dominated by IDom. If so, we need a phi-def here.
- if (!needPHI) {
- IDomValue = LiveOutCache[IDom->getBlock()];
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- LiveOutPair Value = LiveOutCache[*PI];
- if (!Value.first || Value.first == IDomValue.first)
- continue;
- // This predecessor is carrying something other than IDomValue.
- // It could be because IDomValue hasn't propagated yet, or it could be
- // because MBB is in the dominance frontier of that value.
- if (MDT.dominates(IDom, Value.second)) {
- needPHI = true;
- break;
- }
- }
- }
-
- // The value may be live-through even if Kill is set, as can happen when
- // we are called from extendRange. In that case LiveOutSeen is true, and
- // LiveOutCache indicates a foreign or missing value.
- LiveOutPair &LOP = LiveOutCache[MBB];
-
- // Create a phi-def if required.
- if (needPHI) {
- ++Changes;
- SlotIndex Start = LIS.getMBBStartIdx(MBB);
- unsigned RegIdx = RegAssign.lookup(Start);
- LiveInterval *LI = Edit->get(RegIdx);
- VNInfo *VNI = LI->getNextValue(Start, 0, LIS.getVNInfoAllocator());
- VNI->setIsPHIDef(true);
- I->Value = VNI;
- // This block is done, we know the final value.
- I->DomNode = 0;
- if (I->Kill.isValid())
- LI->addRange(LiveRange(Start, I->Kill, VNI));
- else {
- LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
- LOP = LiveOutPair(VNI, Node);
- }
- } else if (IDomValue.first) {
- // No phi-def here. Remember incoming value.
- I->Value = IDomValue.first;
- if (I->Kill.isValid())
- continue;
- // Propagate IDomValue if needed:
- // MBB is live-out and doesn't define its own value.
- if (LOP.second != Node && LOP.first != IDomValue.first) {
- ++Changes;
- LOP = IDomValue;
- }
- }
- }
- } while (Changes);
-
- // The values in LiveInBlocks are now accurate. No more phi-defs are needed
- // for these blocks, so we can color the live ranges.
- for (SmallVectorImpl<LiveInBlock>::iterator I = LiveInBlocks.begin(),
- E = LiveInBlocks.end(); I != E; ++I) {
- if (!I->DomNode)
- continue;
- assert(I->Value && "No live-in value found");
- MachineBasicBlock *MBB = I->DomNode->getBlock();
- SlotIndex Start = LIS.getMBBStartIdx(MBB);
- unsigned RegIdx = RegAssign.lookup(Start);
- LiveInterval *LI = Edit->get(RegIdx);
- LI->addRange(LiveRange(Start, I->Kill.isValid() ?
- I->Kill : LIS.getMBBEndIdx(MBB), I->Value));
- }
+ getLRCalc(RegIdx).extend(Edit->get(RegIdx), Idx.getNextSlot(),
+ LIS.getSlotIndexes(), &MDT, &LIS.getVNInfoAllocator());
}
VNInfo *SplitEditor::defFromParent(unsigned RegIdx,
/// Values that were rematerialized are left alone, they need extendRange().
bool SplitEditor::transferValues() {
bool Skipped = false;
- LiveInBlocks.clear();
RegAssignMap::const_iterator AssignI = RegAssign.begin();
for (LiveInterval::const_iterator ParentI = Edit->getParent().begin(),
ParentE = Edit->getParent().end(); ParentI != ParentE; ++ParentI) {
continue;
}
- // Initialize the live-out cache the first time it is needed.
- if (LiveOutSeen.empty()) {
- unsigned N = VRM.getMachineFunction().getNumBlockIDs();
- LiveOutSeen.resize(N);
- LiveOutCache.resize(N);
- }
+ LiveRangeCalc &LRC = getLRCalc(RegIdx);
// This value has multiple defs in RegIdx, but it wasn't rematerialized,
// so the live range is accurate. Add live-in blocks in [Start;End) to the
// The first block may be live-in, or it may have its own def.
if (Start != BlockStart) {
- VNInfo *VNI = LI->extendInBlock(BlockStart,
- std::min(BlockEnd, End).getPrevSlot());
+ VNInfo *VNI = LI->extendInBlock(BlockStart, std::min(BlockEnd, End));
assert(VNI && "Missing def for complex mapped value");
DEBUG(dbgs() << ':' << VNI->id << "*BB#" << MBB->getNumber());
// MBB has its own def. Is it also live-out?
- if (BlockEnd <= End) {
- LiveOutSeen.set(MBB->getNumber());
- LiveOutCache[MBB] = LiveOutPair(VNI, MDT[MBB]);
- }
+ if (BlockEnd <= End)
+ LRC.setLiveOutValue(MBB, VNI);
+
// Skip to the next block for live-in.
++MBB;
BlockStart = BlockEnd;
if (BlockStart == ParentVNI->def) {
// This block has the def of a parent PHI, so it isn't live-in.
assert(ParentVNI->isPHIDef() && "Non-phi defined at block start?");
- VNInfo *VNI = LI->extendInBlock(BlockStart,
- std::min(BlockEnd, End).getPrevSlot());
+ VNInfo *VNI = LI->extendInBlock(BlockStart, std::min(BlockEnd, End));
assert(VNI && "Missing def for complex mapped parent PHI");
- if (End >= BlockEnd) {
- // Live-out as well.
- LiveOutSeen.set(MBB->getNumber());
- LiveOutCache[MBB] = LiveOutPair(VNI, MDT[MBB]);
- }
+ if (End >= BlockEnd)
+ LRC.setLiveOutValue(MBB, VNI); // Live-out as well.
} else {
- // This block needs a live-in value.
- LiveInBlocks.push_back(MDT[MBB]);
- // The last block covered may not be live-out.
+ // This block needs a live-in value. The last block covered may not
+ // be live-out.
if (End < BlockEnd)
- LiveInBlocks.back().Kill = End;
+ LRC.addLiveInBlock(LI, MDT[MBB], End);
else {
- // Live-out, but we need updateSSA to tell us the value.
- LiveOutSeen.set(MBB->getNumber());
- LiveOutCache[MBB] = LiveOutPair((VNInfo*)0,
- (MachineDomTreeNode*)0);
+ // Live-through, and we don't know the value.
+ LRC.addLiveInBlock(LI, MDT[MBB]);
+ LRC.setLiveOutValue(MBB, 0);
}
}
BlockStart = BlockEnd;
DEBUG(dbgs() << '\n');
}
- if (!LiveInBlocks.empty())
- updateSSA();
+ LRCalc[0].calculateValues(LIS.getSlotIndexes(), &MDT,
+ &LIS.getVNInfoAllocator());
+ if (SpillMode)
+ LRCalc[1].calculateValues(LIS.getSlotIndexes(), &MDT,
+ &LIS.getVNInfoAllocator());
return Skipped;
}
projects / oota-llvm.git / blobdiff