Revert r135074 and r135080. They broke clamscan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135096 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/InterferenceCache.h

@@ -127,14 +127,10 @@ public:
     Entry *CacheEntry;
     BlockInterference *Current;
   public:
-    /// Cursor - Create a dangling cursor.
-    Cursor() : CacheEntry(0), Current(0) {}
-
-    /// setPhysReg - Point this cursor to PhysReg's interference.
-    void setPhysReg(InterferenceCache &Cache, unsigned PhysReg) {
-      CacheEntry = Cache.get(PhysReg);
-      Current = 0;
-    }
+    /// Cursor - Create a cursor for the interference allocated to PhysReg and
+    /// all its aliases.
+    Cursor(InterferenceCache &Cache, unsigned PhysReg)
+      : CacheEntry(Cache.get(PhysReg)), Current(0) {}
 
     /// moveTo - Move cursor to basic block MBBNum.
     void moveToBlock(unsigned MBBNum) {

lib/CodeGen/RegAllocGreedy.cpp

@@ -160,13 +160,11 @@ class RAGreedy : public MachineFunctionPass,
   /// Global live range splitting candidate info.
   struct GlobalSplitCandidate {
     unsigned PhysReg;
-    InterferenceCache::Cursor Intf;
     BitVector LiveBundles;
     SmallVector<unsigned, 8> ActiveBlocks;
 
-    void reset(InterferenceCache &Cache, unsigned Reg) {
+    void reset(unsigned Reg) {
       PhysReg = Reg;
-      Intf.setPhysReg(Cache, Reg);
       LiveBundles.clear();
       ActiveBlocks.clear();
     }
@@ -208,8 +206,8 @@ private:
   float calcSpillCost();
   bool addSplitConstraints(InterferenceCache::Cursor, float&);
   void addThroughConstraints(InterferenceCache::Cursor, ArrayRef<unsigned>);
-  void growRegion(GlobalSplitCandidate &Cand);
-  float calcGlobalSplitCost(GlobalSplitCandidate&);
+  void growRegion(GlobalSplitCandidate &Cand, InterferenceCache::Cursor);
+  float calcGlobalSplitCost(GlobalSplitCandidate&, InterferenceCache::Cursor);
   void splitAroundRegion(LiveInterval&, GlobalSplitCandidate&,
                          SmallVectorImpl<LiveInterval*>&);
   void calcGapWeights(unsigned, SmallVectorImpl<float>&);
@@ -722,7 +720,8 @@ void RAGreedy::addThroughConstraints(InterferenceCache::Cursor Intf,
   SpillPlacer->addLinks(ArrayRef<unsigned>(TBS, T));
 }
 
-void RAGreedy::growRegion(GlobalSplitCandidate &Cand) {
+void RAGreedy::growRegion(GlobalSplitCandidate &Cand,
+                          InterferenceCache::Cursor Intf) {
   // Keep track of through blocks that have not been added to SpillPlacer.
   BitVector Todo = SA->getThroughBlocks();
   SmallVectorImpl<unsigned> &ActiveBlocks = Cand.ActiveBlocks;
@@ -754,7 +753,7 @@ void RAGreedy::growRegion(GlobalSplitCandidate &Cand) {
     // Any new blocks to add?
     if (ActiveBlocks.size() == AddedTo)
       break;
-    addThroughConstraints(Cand.Intf,
+    addThroughConstraints(Intf,
                           ArrayRef<unsigned>(ActiveBlocks).slice(AddedTo));
     AddedTo = ActiveBlocks.size();
 
@@ -795,7 +794,8 @@ float RAGreedy::calcSpillCost() {
 /// pattern in LiveBundles. This cost should be added to the local cost of the
 /// interference pattern in SplitConstraints.
 ///
-float RAGreedy::calcGlobalSplitCost(GlobalSplitCandidate &Cand) {
+float RAGreedy::calcGlobalSplitCost(GlobalSplitCandidate &Cand,
+                                    InterferenceCache::Cursor Intf) {
   float GlobalCost = 0;
   const BitVector &LiveBundles = Cand.LiveBundles;
   ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
@@ -822,8 +822,8 @@ float RAGreedy::calcGlobalSplitCost(GlobalSplitCandidate &Cand) {
       continue;
     if (RegIn && RegOut) {
       // We need double spill code if this block has interference.
-      Cand.Intf.moveToBlock(Number);
-      if (Cand.Intf.hasInterference())
+      Intf.moveToBlock(Number);
+      if (Intf.hasInterference())
         GlobalCost += 2*SpillPlacer->getBlockFrequency(Number);
       continue;
     }
@@ -853,7 +853,7 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg,
     dbgs() << ".\n";
   });
 
-  InterferenceCache::Cursor &Intf = Cand.Intf;
+  InterferenceCache::Cursor Intf(IntfCache, Cand.PhysReg);
   LiveRangeEdit LREdit(VirtReg, NewVRegs, this);
   SE->reset(LREdit);
 
@@ -1243,18 +1243,17 @@ unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
   DEBUG(dbgs() << "Cost of isolating all blocks = " << BestCost << '\n');
   const unsigned NoCand = ~0u;
   unsigned BestCand = NoCand;
-  unsigned NumCands = 0;
 
   Order.rewind();
-  while (unsigned PhysReg = Order.next()) {
-    if (GlobalCand.size() <= NumCands)
-      GlobalCand.resize(NumCands+1);
-    GlobalSplitCandidate &Cand = GlobalCand[NumCands];
-    Cand.reset(IntfCache, PhysReg);
+  for (unsigned Cand = 0; unsigned PhysReg = Order.next(); ++Cand) {
+    if (GlobalCand.size() <= Cand)
+      GlobalCand.resize(Cand+1);
+    GlobalCand[Cand].reset(PhysReg);
 
-    SpillPlacer->prepare(Cand.LiveBundles);
+    SpillPlacer->prepare(GlobalCand[Cand].LiveBundles);
     float Cost;
-    if (!addSplitConstraints(Cand.Intf, Cost)) {
+    InterferenceCache::Cursor Intf(IntfCache, PhysReg);
+    if (!addSplitConstraints(Intf, Cost)) {
       DEBUG(dbgs() << PrintReg(PhysReg, TRI) << "\tno positive bundles\n");
       continue;
     }
@@ -1269,29 +1268,28 @@ unsigned RAGreedy::tryRegionSplit(LiveInterval &VirtReg, AllocationOrder &Order,
       });
       continue;
     }
-    growRegion(Cand);
+    growRegion(GlobalCand[Cand], Intf);
 
     SpillPlacer->finish();
 
     // No live bundles, defer to splitSingleBlocks().
-    if (!Cand.LiveBundles.any()) {
+    if (!GlobalCand[Cand].LiveBundles.any()) {
       DEBUG(dbgs() << " no bundles.\n");
       continue;
     }
 
-    Cost += calcGlobalSplitCost(Cand);
+    Cost += calcGlobalSplitCost(GlobalCand[Cand], Intf);
     DEBUG({
       dbgs() << ", total = " << Cost << " with bundles";
-      for (int i = Cand.LiveBundles.find_first(); i>=0;
-           i = Cand.LiveBundles.find_next(i))
+      for (int i = GlobalCand[Cand].LiveBundles.find_first(); i>=0;
+           i = GlobalCand[Cand].LiveBundles.find_next(i))
         dbgs() << " EB#" << i;
       dbgs() << ".\n";
     });
     if (Cost < BestCost) {
-      BestCand = NumCands;
+      BestCand = Cand;
       BestCost = Hysteresis * Cost; // Prevent rounding effects.
     }
-    ++NumCands;
   }
 
   if (BestCand == NoCand)