Reapply r63025 and r63026, with fixes for the failing testcases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63049 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/PreAllocSplitting.cpp

@@ -139,26 +139,11 @@ namespace {
 
     void UpdateSpillSlotInterval(VNInfo*, unsigned, unsigned);
 
-    VNInfo* UpdateRegisterInterval(VNInfo*, unsigned, unsigned);
-
-    bool ShrinkWrapToLastUse(MachineBasicBlock*, VNInfo*,
-                             SmallVector<MachineOperand*, 4>&,
-                             SmallPtrSet<MachineInstr*, 4>&);
-
-    void ShrinkWrapLiveInterval(VNInfo*, MachineBasicBlock*, MachineBasicBlock*,
-                        MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*, 8>&,
-                DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >&,
-                  DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >&,
-                                SmallVector<MachineBasicBlock*, 4>&);
-
     bool SplitRegLiveInterval(LiveInterval*);
 
     bool SplitRegLiveIntervals(const TargetRegisterClass **,
                                SmallPtrSet<LiveInterval*, 8>&);
     
-    void RepairLiveInterval(LiveInterval* CurrLI, VNInfo* ValNo,
-                            MachineInstr* DefMI, unsigned RestoreIdx);
-    
     bool createsNewJoin(LiveRange* LR, MachineBasicBlock* DefMBB,
                         MachineBasicBlock* BarrierMBB);
     bool Rematerialize(unsigned vreg, VNInfo* ValNo,
@@ -423,176 +408,6 @@ PreAllocSplitting::UpdateSpillSlotInterval(VNInfo *ValNo, unsigned SpillIndex,
   }
 }
 
-/// UpdateRegisterInterval - Given the specified val# of the current live
-/// interval is being split, and the spill and restore indices, update the live
-/// interval accordingly.
-VNInfo*
-PreAllocSplitting::UpdateRegisterInterval(VNInfo *ValNo, unsigned SpillIndex,
-                                          unsigned RestoreIndex) {
-  assert(LIs->getMBBFromIndex(RestoreIndex) == BarrierMBB &&
-         "Expect restore in the barrier mbb");
-
-  SmallVector<std::pair<unsigned,unsigned>, 4> Before;
-  SmallVector<std::pair<unsigned,unsigned>, 4> After;
-  SmallVector<unsigned, 4> BeforeKills;
-  SmallVector<unsigned, 4> AfterKills;
-  SmallPtrSet<const LiveRange*, 4> Processed;
-
-  // First, let's figure out which parts of the live interval is now defined
-  // by the restore, which are defined by the original definition.
-  const LiveRange *LR = CurrLI->getLiveRangeContaining(RestoreIndex);
-  After.push_back(std::make_pair(RestoreIndex, LR->end));
-  if (CurrLI->isKill(ValNo, LR->end))
-    AfterKills.push_back(LR->end);
-
-  assert(LR->contains(SpillIndex));
-  if (SpillIndex > LR->start) {
-    Before.push_back(std::make_pair(LR->start, SpillIndex));
-    BeforeKills.push_back(SpillIndex);
-  }
-  Processed.insert(LR);
-
-  // Start from the restore mbb, figure out what part of the live interval
-  // are defined by the restore.
-  SmallVector<MachineBasicBlock*, 4> WorkList;
-  MachineBasicBlock *MBB = BarrierMBB;
-  for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
-         SE = MBB->succ_end(); SI != SE; ++SI)
-    WorkList.push_back(*SI);
-
-  SmallPtrSet<MachineBasicBlock*, 4> ProcessedBlocks;
-  ProcessedBlocks.insert(MBB);
-
-  while (!WorkList.empty()) {
-    MBB = WorkList.back();
-    WorkList.pop_back();
-    unsigned Idx = LIs->getMBBStartIdx(MBB);
-    LR = CurrLI->getLiveRangeContaining(Idx);
-    if (LR && LR->valno == ValNo && !Processed.count(LR)) {
-      After.push_back(std::make_pair(LR->start, LR->end));
-      if (CurrLI->isKill(ValNo, LR->end))
-        AfterKills.push_back(LR->end);
-      Idx = LIs->getMBBEndIdx(MBB);
-      if (LR->end > Idx) {
-        // Live range extend beyond at least one mbb. Let's see what other
-        // mbbs it reaches.
-        LIs->findReachableMBBs(LR->start, LR->end, WorkList);
-      }
-      Processed.insert(LR);
-    }
-    
-    ProcessedBlocks.insert(MBB);
-    if (LR)
-      for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
-            SE = MBB->succ_end(); SI != SE; ++SI)
-        if (!ProcessedBlocks.count(*SI))
-          WorkList.push_back(*SI);
-  }
-
-  for (LiveInterval::iterator I = CurrLI->begin(), E = CurrLI->end();
-       I != E; ++I) {
-    LiveRange *LR = I;
-    if (LR->valno == ValNo && !Processed.count(LR)) {
-      Before.push_back(std::make_pair(LR->start, LR->end));
-      if (CurrLI->isKill(ValNo, LR->end))
-        BeforeKills.push_back(LR->end);
-    }
-  }
-
-  // Now create new val#s to represent the live ranges defined by the old def
-  // those defined by the restore.
-  unsigned AfterDef = ValNo->def;
-  MachineInstr *AfterCopy = ValNo->copy;
-  bool HasPHIKill = ValNo->hasPHIKill;
-  CurrLI->removeValNo(ValNo);
-  VNInfo *BValNo = (Before.empty())
-    ? NULL
-    : CurrLI->getNextValue(AfterDef, AfterCopy, LIs->getVNInfoAllocator());
-  if (BValNo)
-    CurrLI->addKills(BValNo, BeforeKills);
-
-  VNInfo *AValNo = (After.empty())
-    ? NULL
-    : CurrLI->getNextValue(RestoreIndex, 0, LIs->getVNInfoAllocator());
-  if (AValNo) {
-    AValNo->hasPHIKill = HasPHIKill;
-    CurrLI->addKills(AValNo, AfterKills);
-  }
-
-  for (unsigned i = 0, e = Before.size(); i != e; ++i) {
-    unsigned Start = Before[i].first;
-    unsigned End   = Before[i].second;
-    CurrLI->addRange(LiveRange(Start, End, BValNo));
-  }
-  for (unsigned i = 0, e = After.size(); i != e; ++i) {
-    unsigned Start = After[i].first;
-    unsigned End   = After[i].second;
-    CurrLI->addRange(LiveRange(Start, End, AValNo));
-  }
-  
-  return AValNo;
-}
-
-/// ShrinkWrapToLastUse - There are uses of the current live interval in the
-/// given block, shrink wrap the live interval to the last use (i.e. remove
-/// from last use to the end of the mbb). In case mbb is the where the barrier
-/// is, remove from the last use to the barrier.
-bool
-PreAllocSplitting::ShrinkWrapToLastUse(MachineBasicBlock *MBB, VNInfo *ValNo,
-                                       SmallVector<MachineOperand*, 4> &Uses,
-                                       SmallPtrSet<MachineInstr*, 4> &UseMIs) {
-  MachineOperand *LastMO = 0;
-  MachineInstr *LastMI = 0;
-  if (MBB != BarrierMBB && Uses.size() == 1) {
-    // Single use, no need to traverse the block. We can't assume this for the
-    // barrier bb though since the use is probably below the barrier.
-    LastMO = Uses[0];
-    LastMI = LastMO->getParent();
-  } else {
-    MachineBasicBlock::iterator MEE = MBB->begin();
-    MachineBasicBlock::iterator MII;
-    if (MBB == BarrierMBB)
-      MII = Barrier;
-    else
-      MII = MBB->end();
-    while (MII != MEE) {
-      --MII;
-      MachineInstr *UseMI = &*MII;
-      if (!UseMIs.count(UseMI))
-        continue;
-      for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) {
-        MachineOperand &MO = UseMI->getOperand(i);
-        if (MO.isReg() && MO.getReg() == CurrLI->reg) {
-          LastMO = &MO;
-          break;
-        }
-      }
-      LastMI = UseMI;
-      break;
-    }
-  }
-
-  // Cut off live range from last use (or beginning of the mbb if there
-  // are no uses in it) to the end of the mbb.
-  unsigned RangeStart, RangeEnd = LIs->getMBBEndIdx(MBB)+1;
-  if (LastMI) {
-    RangeStart = LIs->getUseIndex(LIs->getInstructionIndex(LastMI))+1;
-    assert(!LastMO->isKill() && "Last use already terminates the interval?");
-    LastMO->setIsKill();
-  } else {
-    assert(MBB == BarrierMBB);
-    RangeStart = LIs->getMBBStartIdx(MBB);
-  }
-  if (MBB == BarrierMBB)
-    RangeEnd = LIs->getUseIndex(BarrierIdx)+1;
-  CurrLI->removeRange(RangeStart, RangeEnd);
-  if (LastMI)
-    CurrLI->addKill(ValNo, RangeStart);
-
-  // Return true if the last use becomes a new kill.
-  return LastMI;
-}
-
 /// PerformPHIConstruction - From properly set up use and def lists, use a PHI
 /// construction algorithm to compute the ranges and valnos for an interval.
 VNInfo* PreAllocSplitting::PerformPHIConstruction(
@@ -748,12 +563,12 @@ VNInfo* PreAllocSplitting::PerformPHIConstruction(
     ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
                                  NewVNs, LiveOut, Phis, false, true);
     
+    LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
+    
     // FIXME: Need to set kills properly for inter-block stuff.
     if (LI->isKill(ret, UseIndex)) LI->removeKill(ret, UseIndex);
     if (intrablock)
       LI->addKill(ret, EndIndex);
-    
-    LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
   } else if (ContainsDefs && ContainsUses){
     SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
     SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
@@ -805,13 +620,13 @@ VNInfo* PreAllocSplitting::PerformPHIConstruction(
       ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
                                    NewVNs, LiveOut, Phis, false, true);
 
+    LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
+    
     if (foundUse && LI->isKill(ret, StartIndex))
       LI->removeKill(ret, StartIndex);
     if (intrablock) {
       LI->addKill(ret, EndIndex);
     }
-
-    LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
   }
   
   // Memoize results so we don't have to recompute them.
@@ -890,142 +705,6 @@ void PreAllocSplitting::ReconstructLiveInterval(LiveInterval* LI) {
   }
 }
 
-/// ShrinkWrapLiveInterval - Recursively traverse the predecessor
-/// chain to find the new 'kills' and shrink wrap the live interval to the
-/// new kill indices.
-void
-PreAllocSplitting::ShrinkWrapLiveInterval(VNInfo *ValNo, MachineBasicBlock *MBB,
-                          MachineBasicBlock *SuccMBB, MachineBasicBlock *DefMBB,
-                                    SmallPtrSet<MachineBasicBlock*, 8> &Visited,
-           DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > &Uses,
-           DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > &UseMIs,
-                                  SmallVector<MachineBasicBlock*, 4> &UseMBBs) {
-  if (Visited.count(MBB))
-    return;
-
-  // If live interval is live in another successor path, then we can't process
-  // this block. But we may able to do so after all the successors have been
-  // processed.
-  if (MBB != BarrierMBB) {
-    for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
-           SE = MBB->succ_end(); SI != SE; ++SI) {
-      MachineBasicBlock *SMBB = *SI;
-      if (SMBB == SuccMBB)
-        continue;
-      if (CurrLI->liveAt(LIs->getMBBStartIdx(SMBB)))
-        return;
-    }
-  }
-
-  Visited.insert(MBB);
-
-  DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
-    UMII = Uses.find(MBB);
-  if (UMII != Uses.end()) {
-    // At least one use in this mbb, lets look for the kill.
-    DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
-      UMII2 = UseMIs.find(MBB);
-    if (ShrinkWrapToLastUse(MBB, ValNo, UMII->second, UMII2->second))
-      // Found a kill, shrink wrapping of this path ends here.
-      return;
-  } else if (MBB == DefMBB) {
-    // There are no uses after the def.
-    MachineInstr *DefMI = LIs->getInstructionFromIndex(ValNo->def);
-    if (UseMBBs.empty()) {
-      // The only use must be below barrier in the barrier block. It's safe to
-      // remove the def.
-      LIs->RemoveMachineInstrFromMaps(DefMI);
-      DefMI->eraseFromParent();
-      CurrLI->removeRange(ValNo->def, LIs->getMBBEndIdx(MBB)+1);
-    }
-  } else if (MBB == BarrierMBB) {
-    // Remove entire live range from start of mbb to barrier.
-    CurrLI->removeRange(LIs->getMBBStartIdx(MBB),
-                        LIs->getUseIndex(BarrierIdx)+1);
-  } else {
-    // Remove entire live range of the mbb out of the live interval.
-    CurrLI->removeRange(LIs->getMBBStartIdx(MBB), LIs->getMBBEndIdx(MBB)+1);
-  }
-
-  if (MBB == DefMBB)
-    // Reached the def mbb, stop traversing this path further.
-    return;
-
-  // Traverse the pathes up the predecessor chains further.
-  for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
-         PE = MBB->pred_end(); PI != PE; ++PI) {
-    MachineBasicBlock *Pred = *PI;
-    if (Pred == MBB)
-      continue;
-    if (Pred == DefMBB && ValNo->hasPHIKill)
-      // Pred is the def bb and the def reaches other val#s, we must
-      // allow the value to be live out of the bb.
-      continue;
-    if (!CurrLI->liveAt(LIs->getMBBEndIdx(Pred)-1))
-      return;
-    ShrinkWrapLiveInterval(ValNo, Pred, MBB, DefMBB, Visited,
-                           Uses, UseMIs, UseMBBs);
-  }
-
-  return;
-}
-
-
-void PreAllocSplitting::RepairLiveInterval(LiveInterval* CurrLI,
-                                           VNInfo* ValNo,
-                                           MachineInstr* DefMI,
-                                           unsigned RestoreIdx) {
-  // Shrink wrap the live interval by walking up the CFG and find the
-  // new kills.
-  // Now let's find all the uses of the val#.
-  DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > Uses;
-  DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > UseMIs;
-  SmallPtrSet<MachineBasicBlock*, 4> Seen;
-  SmallVector<MachineBasicBlock*, 4> UseMBBs;
-  for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(CurrLI->reg),
-         UE = MRI->use_end(); UI != UE; ++UI) {
-    MachineOperand &UseMO = UI.getOperand();
-    MachineInstr *UseMI = UseMO.getParent();
-    unsigned UseIdx = LIs->getInstructionIndex(UseMI);
-    LiveInterval::iterator ULR = CurrLI->FindLiveRangeContaining(UseIdx);
-    if (ULR->valno != ValNo)
-      continue;
-    MachineBasicBlock *UseMBB = UseMI->getParent();
-    // Remember which other mbb's use this val#.
-    if (Seen.insert(UseMBB) && UseMBB != BarrierMBB)
-      UseMBBs.push_back(UseMBB);
-    DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
-      UMII = Uses.find(UseMBB);
-    if (UMII != Uses.end()) {
-      DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >::iterator
-        UMII2 = UseMIs.find(UseMBB);
-      UMII->second.push_back(&UseMO);
-      UMII2->second.insert(UseMI);
-    } else {
-      SmallVector<MachineOperand*, 4> Ops;
-      Ops.push_back(&UseMO);
-      Uses.insert(std::make_pair(UseMBB, Ops));
-      SmallPtrSet<MachineInstr*, 4> MIs;
-      MIs.insert(UseMI);
-      UseMIs.insert(std::make_pair(UseMBB, MIs));
-    }
-  }
-
-  // Walk up the predecessor chains.
-  SmallPtrSet<MachineBasicBlock*, 8> Visited;
-  ShrinkWrapLiveInterval(ValNo, BarrierMBB, NULL, DefMI->getParent(), Visited,
-                         Uses, UseMIs, UseMBBs);
-
-  // Remove live range from barrier to the restore. FIXME: Find a better
-  // point to re-start the live interval.
-  VNInfo* AfterValNo = UpdateRegisterInterval(ValNo,
-                                              LIs->getUseIndex(BarrierIdx)+1,
-                                              LIs->getDefIndex(RestoreIdx));
-  
-  // Attempt to renumber the new valno into a new vreg.
-  RenumberValno(AfterValNo);
-}
-
 /// RenumberValno - Split the given valno out into a new vreg, allowing it to
 /// be allocated to a different register.  This function creates a new vreg,
 /// copies the valno and its live ranges over to the new vreg's interval,
@@ -1055,12 +734,12 @@ void PreAllocSplitting::RenumberValno(VNInfo* VN) {
     for (SmallVector<unsigned, 4>::iterator KI = OldVN->kills.begin(),
          KE = OldVN->kills.end(); KI != KE; ++KI) {
       MachineInstr* MI = LIs->getInstructionFromIndex(*KI);
-      //if (!MI) continue;
       unsigned DefIdx = MI->findRegisterDefOperandIdx(CurrLI->reg);
       if (DefIdx == ~0U) continue;
       if (MI->isRegReDefinedByTwoAddr(DefIdx)) {
         VNInfo* NextVN =
                      CurrLI->findDefinedVNInfo(LiveIntervals::getDefIndex(*KI));
+        if (NextVN == OldVN) continue;
         Stack.push_back(NextVN);
       }
     }
@@ -1131,18 +810,10 @@ bool PreAllocSplitting::Rematerialize(unsigned vreg, VNInfo* ValNo,
   TII->reMaterialize(MBB, RestorePt, vreg, DefMI);
   LIs->InsertMachineInstrInMaps(prior(RestorePt), RestoreIdx);
   
-  if (KillPt->getParent() == BarrierMBB) {
+  ReconstructLiveInterval(CurrLI);
-    VNInfo* After = UpdateRegisterInterval(ValNo, LIs->getUseIndex(KillIdx)+1,
+  unsigned RematIdx = LIs->getInstructionIndex(prior(RestorePt));
-                           LIs->getDefIndex(RestoreIdx));
+  RematIdx = LiveIntervals::getDefIndex(RematIdx);
-    
+  RenumberValno(CurrLI->findDefinedVNInfo(RematIdx));
-    RenumberValno(After);
-
-    ++NumSplits;
-    ++NumRemats;
-    return true;
-  }
-
-  RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIdx);
   
   ++NumSplits;
   ++NumRemats;
@@ -1315,28 +986,14 @@ bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) {
   MachineInstr *LoadMI = prior(RestorePt);
   LIs->InsertMachineInstrInMaps(LoadMI, RestoreIndex);
 
-  // If live interval is spilled in the same block as the barrier, just
-  // create a hole in the interval.
-  if (!DefMBB ||
-      (SpillMI && SpillMI->getParent() == BarrierMBB)) {
-    // Update spill stack slot live interval.
-    UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
-                            LIs->getDefIndex(RestoreIndex));
-
-    VNInfo* After = UpdateRegisterInterval(ValNo,
-                           LIs->getUseIndex(SpillIndex)+1,
-                           LIs->getDefIndex(RestoreIndex));
-    RenumberValno(After);
-   
-    ++NumSplits;
-    return true;
-  }
-
   // Update spill stack slot live interval.
   UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
                           LIs->getDefIndex(RestoreIndex));
 
-  RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIndex);
+  ReconstructLiveInterval(CurrLI);
+  unsigned RestoreIdx = LIs->getInstructionIndex(prior(RestorePt));
+  RestoreIdx = LiveIntervals::getDefIndex(RestoreIdx);
+  RenumberValno(CurrLI->findDefinedVNInfo(RestoreIdx));
   
   ++NumSplits;
   return true;