Revert r85346 change to control tail merging by CodeGenOpt::Level.
[oota-llvm.git] / lib / CodeGen / Spiller.cpp
index eb2a8a10b2555ca9bc08a7b1eadf47472be4082a..0277d64cdd960c8523097d27b5752f6414bf1aff 100644 (file)
 #include "Spiller.h"
 #include "VirtRegMap.h"
 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Support/Debug.h"
-
-#include <algorithm>
-#include <map>
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
@@ -28,19 +27,197 @@ Spiller::~Spiller() {}
 
 namespace {
 
-class TrivialSpiller : public Spiller {
-public:
-  TrivialSpiller(MachineFunction *mf, LiveIntervals *lis, VirtRegMap *vrm) :
-    mf(mf), lis(lis), vrm(vrm)
+/// Utility class for spillers.
+class SpillerBase : public Spiller {
+protected:
+
+  MachineFunction *mf;
+  LiveIntervals *lis;
+  LiveStacks *ls;
+  MachineFrameInfo *mfi;
+  MachineRegisterInfo *mri;
+  const TargetInstrInfo *tii;
+  VirtRegMap *vrm;
+  
+  /// Construct a spiller base. 
+  SpillerBase(MachineFunction *mf, LiveIntervals *lis, LiveStacks *ls,
+              VirtRegMap *vrm) :
+    mf(mf), lis(lis), ls(ls), vrm(vrm)
   {
     mfi = mf->getFrameInfo();
     mri = &mf->getRegInfo();
     tii = mf->getTarget().getInstrInfo();
   }
 
-  std::vector<LiveInterval*> spill(LiveInterval *li) {
+  /// Ensures there is space before the given machine instruction, returns the
+  /// instruction's new number.
+  LiveIndex makeSpaceBefore(MachineInstr *mi) {
+    if (!lis->hasGapBeforeInstr(lis->getInstructionIndex(mi))) {
+      lis->scaleNumbering(2);
+      ls->scaleNumbering(2);
+    }
+
+    LiveIndex miIdx = lis->getInstructionIndex(mi);
+
+    assert(lis->hasGapBeforeInstr(miIdx));
+    
+    return miIdx;
+  }
+
+  /// Ensure there is space after the given machine instruction, returns the
+  /// instruction's new number.
+  LiveIndex makeSpaceAfter(MachineInstr *mi) {
+    if (!lis->hasGapAfterInstr(lis->getInstructionIndex(mi))) {
+      lis->scaleNumbering(2);
+      ls->scaleNumbering(2);
+    }
+
+    LiveIndex miIdx = lis->getInstructionIndex(mi);
+
+    assert(lis->hasGapAfterInstr(miIdx));
+
+    return miIdx;
+  }  
+
+  /// Insert a store of the given vreg to the given stack slot immediately
+  /// after the given instruction. Returns the base index of the inserted
+  /// instruction. The caller is responsible for adding an appropriate
+  /// LiveInterval to the LiveIntervals analysis.
+  LiveIndex insertStoreAfter(MachineInstr *mi, unsigned ss,
+                                     unsigned vreg,
+                                     const TargetRegisterClass *trc) {
+
+    MachineBasicBlock::iterator nextInstItr(next(mi)); 
+
+    LiveIndex miIdx = makeSpaceAfter(mi);
+
+    tii->storeRegToStackSlot(*mi->getParent(), nextInstItr, vreg,
+                             true, ss, trc);
+    MachineBasicBlock::iterator storeInstItr(next(mi));
+    MachineInstr *storeInst = &*storeInstItr;
+    LiveIndex storeInstIdx = lis->getNextIndex(miIdx);
+
+    assert(lis->getInstructionFromIndex(storeInstIdx) == 0 &&
+           "Store inst index already in use.");
+    
+    lis->InsertMachineInstrInMaps(storeInst, storeInstIdx);
+
+    return storeInstIdx;
+  }
+
+  /// Insert a store of the given vreg to the given stack slot immediately
+  /// before the given instructnion. Returns the base index of the inserted
+  /// Instruction.
+  LiveIndex insertStoreBefore(MachineInstr *mi, unsigned ss,
+                                      unsigned vreg,
+                                      const TargetRegisterClass *trc) {
+    LiveIndex miIdx = makeSpaceBefore(mi);
+  
+    tii->storeRegToStackSlot(*mi->getParent(), mi, vreg, true, ss, trc);
+    MachineBasicBlock::iterator storeInstItr(prior(mi));
+    MachineInstr *storeInst = &*storeInstItr;
+    LiveIndex storeInstIdx = lis->getPrevIndex(miIdx);
+
+    assert(lis->getInstructionFromIndex(storeInstIdx) == 0 &&
+           "Store inst index already in use.");
+
+    lis->InsertMachineInstrInMaps(storeInst, storeInstIdx);
+
+    return storeInstIdx;
+  }
+
+  void insertStoreAfterInstOnInterval(LiveInterval *li,
+                                      MachineInstr *mi, unsigned ss,
+                                      unsigned vreg,
+                                      const TargetRegisterClass *trc) {
+
+    LiveIndex storeInstIdx = insertStoreAfter(mi, ss, vreg, trc);
+    LiveIndex start = lis->getDefIndex(lis->getInstructionIndex(mi)),
+                      end = lis->getUseIndex(storeInstIdx);
+
+    VNInfo *vni =
+      li->getNextValue(storeInstIdx, 0, true, lis->getVNInfoAllocator());
+    vni->addKill(storeInstIdx);
+    DEBUG(errs() << "    Inserting store range: [" << start
+                 << ", " << end << ")\n");
+    LiveRange lr(start, end, vni);
+      
+    li->addRange(lr);
+  }
 
-    DOUT << "Trivial spiller spilling " << *li << "\n";
+  /// Insert a load of the given vreg from the given stack slot immediately
+  /// after the given instruction. Returns the base index of the inserted
+  /// instruction. The caller is responsibel for adding/removing an appropriate
+  /// range vreg's LiveInterval.
+  LiveIndex insertLoadAfter(MachineInstr *mi, unsigned ss,
+                                    unsigned vreg,
+                                    const TargetRegisterClass *trc) {
+
+    MachineBasicBlock::iterator nextInstItr(next(mi)); 
+
+    LiveIndex miIdx = makeSpaceAfter(mi);
+
+    tii->loadRegFromStackSlot(*mi->getParent(), nextInstItr, vreg, ss, trc);
+    MachineBasicBlock::iterator loadInstItr(next(mi));
+    MachineInstr *loadInst = &*loadInstItr;
+    LiveIndex loadInstIdx = lis->getNextIndex(miIdx);
+
+    assert(lis->getInstructionFromIndex(loadInstIdx) == 0 &&
+           "Store inst index already in use.");
+    
+    lis->InsertMachineInstrInMaps(loadInst, loadInstIdx);
+
+    return loadInstIdx;
+  }
+
+  /// Insert a load of the given vreg from the given stack slot immediately
+  /// before the given instruction. Returns the base index of the inserted
+  /// instruction. The caller is responsible for adding an appropriate
+  /// LiveInterval to the LiveIntervals analysis.
+  LiveIndex insertLoadBefore(MachineInstr *mi, unsigned ss,
+                                     unsigned vreg,
+                                     const TargetRegisterClass *trc) {  
+    LiveIndex miIdx = makeSpaceBefore(mi);
+  
+    tii->loadRegFromStackSlot(*mi->getParent(), mi, vreg, ss, trc);
+    MachineBasicBlock::iterator loadInstItr(prior(mi));
+    MachineInstr *loadInst = &*loadInstItr;
+    LiveIndex loadInstIdx = lis->getPrevIndex(miIdx);
+
+    assert(lis->getInstructionFromIndex(loadInstIdx) == 0 &&
+           "Load inst index already in use.");
+
+    lis->InsertMachineInstrInMaps(loadInst, loadInstIdx);
+
+    return loadInstIdx;
+  }
+
+  void insertLoadBeforeInstOnInterval(LiveInterval *li,
+                                      MachineInstr *mi, unsigned ss, 
+                                      unsigned vreg,
+                                      const TargetRegisterClass *trc) {
+
+    LiveIndex loadInstIdx = insertLoadBefore(mi, ss, vreg, trc);
+    LiveIndex start = lis->getDefIndex(loadInstIdx),
+                      end = lis->getUseIndex(lis->getInstructionIndex(mi));
+
+    VNInfo *vni =
+      li->getNextValue(loadInstIdx, 0, true, lis->getVNInfoAllocator());
+    vni->addKill(lis->getInstructionIndex(mi));
+    DEBUG(errs() << "    Intserting load range: [" << start
+                 << ", " << end << ")\n");
+    LiveRange lr(start, end, vni);
+
+    li->addRange(lr);
+  }
+
+
+
+  /// Add spill ranges for every use/def of the live interval, inserting loads
+  /// immediately before each use, and stores after each def. No folding is
+  /// attempted.
+  std::vector<LiveInterval*> trivialSpillEverywhere(LiveInterval *li) {
+    DEBUG(errs() << "Spilling everywhere " << *li << "\n");
 
     assert(li->weight != HUGE_VALF &&
            "Attempting to spill already spilled value.");
@@ -48,19 +225,24 @@ public:
     assert(!li->isStackSlot() &&
            "Trying to spill a stack slot.");
 
+    DEBUG(errs() << "Trivial spill everywhere of reg" << li->reg << "\n");
+
     std::vector<LiveInterval*> added;
     
     const TargetRegisterClass *trc = mri->getRegClass(li->reg);
-    /*unsigned ss = mfi->CreateStackObject(trc->getSize(),
-                                         trc->getAlignment());*/
     unsigned ss = vrm->assignVirt2StackSlot(li->reg);
 
-    MachineRegisterInfo::reg_iterator regItr = mri->reg_begin(li->reg);
-    
-    while (regItr != mri->reg_end()) {
+    for (MachineRegisterInfo::reg_iterator
+         regItr = mri->reg_begin(li->reg); regItr != mri->reg_end();) {
 
       MachineInstr *mi = &*regItr;
 
+      DEBUG(errs() << "  Processing " << *mi);
+
+      do {
+        ++regItr;
+      } while (regItr != mri->reg_end() && (&*regItr == mi));
+      
       SmallVector<unsigned, 2> indices;
       bool hasUse = false;
       bool hasDef = false;
@@ -78,12 +260,12 @@ public:
       }
 
       unsigned newVReg = mri->createVirtualRegister(trc);
-      LiveInterval *newLI = &lis->getOrCreateInterval(newVReg);
-      newLI->weight = HUGE_VALF;
-
       vrm->grow();
       vrm->assignVirt2StackSlot(newVReg, ss);
 
+      LiveInterval *newLI = &lis->getOrCreateInterval(newVReg);
+      newLI->weight = HUGE_VALF;
+      
       for (unsigned i = 0; i < indices.size(); ++i) {
         mi->getOperand(indices[i]).setReg(newVReg);
 
@@ -92,115 +274,92 @@ public:
         }
       }
 
-      if (hasUse) {
-        unsigned loadInstIdx = insertLoadFor(mi, ss, newVReg, trc);
-        unsigned start = lis->getDefIndex(loadInstIdx),
-                 end = lis->getUseIndex(lis->getInstructionIndex(mi));
-
-        VNInfo *vni =
-          newLI->getNextValue(loadInstIdx, 0, lis->getVNInfoAllocator());
-        vni->kills.push_back(lis->getInstructionIndex(mi));
-        LiveRange lr(start, end, vni);
+      assert(hasUse || hasDef);
 
-        newLI->addRange(lr);
-        added.push_back(newLI);
+      if (hasUse) {
+        insertLoadBeforeInstOnInterval(newLI, mi, ss, newVReg, trc);
       }
 
       if (hasDef) {
-        unsigned storeInstIdx = insertStoreFor(mi, ss, newVReg, trc);
-        unsigned start = lis->getDefIndex(lis->getInstructionIndex(mi)),
-                 end = lis->getUseIndex(storeInstIdx);
-
-        VNInfo *vni =
-          newLI->getNextValue(storeInstIdx, 0, lis->getVNInfoAllocator());
-        vni->kills.push_back(storeInstIdx);
-        LiveRange lr(start, end, vni);
-      
-        newLI->addRange(lr);
-        added.push_back(newLI);
+        insertStoreAfterInstOnInterval(newLI, mi, ss, newVReg, trc);
       }
 
-      regItr = mri->reg_begin(li->reg);
+      added.push_back(newLI);
     }
 
-
     return added;
   }
 
-
-private:
-
-  MachineFunction *mf;
-  LiveIntervals *lis;
-  MachineFrameInfo *mfi;
-  MachineRegisterInfo *mri;
-  const TargetInstrInfo *tii;
-  VirtRegMap *vrm;
+};
 
 
+/// Spills any live range using the spill-everywhere method with no attempt at
+/// folding.
+class TrivialSpiller : public SpillerBase {
+public:
 
-  void makeRoomForInsertBefore(MachineInstr *mi) {
-    if (!lis->hasGapBeforeInstr(lis->getInstructionIndex(mi))) {
-      lis->computeNumbering();
-    }
+  TrivialSpiller(MachineFunction *mf, LiveIntervals *lis, LiveStacks *ls,
+                 VirtRegMap *vrm) :
+    SpillerBase(mf, lis, ls, vrm) {}
 
-    assert(lis->hasGapBeforeInstr(lis->getInstructionIndex(mi)));
+  std::vector<LiveInterval*> spill(LiveInterval *li) {
+    return trivialSpillEverywhere(li);
   }
 
-  unsigned insertStoreFor(MachineInstr *mi, unsigned ss,
-                          unsigned newVReg,
-                          const TargetRegisterClass *trc) {
-    MachineBasicBlock::iterator nextInstItr(mi); 
-    ++nextInstItr;
-
-    makeRoomForInsertBefore(&*nextInstItr);
-
-    unsigned miIdx = lis->getInstructionIndex(mi);
-
-    tii->storeRegToStackSlot(*mi->getParent(), nextInstItr, newVReg,
-                             true, ss, trc);
-    MachineBasicBlock::iterator storeInstItr(mi);
-    ++storeInstItr;
-    MachineInstr *storeInst = &*storeInstItr;
-    unsigned storeInstIdx = miIdx + LiveIntervals::InstrSlots::NUM;
+  std::vector<LiveInterval*> intraBlockSplit(LiveInterval *li, VNInfo *valno)  {
+    std::vector<LiveInterval*> spillIntervals;
 
-    assert(lis->getInstructionFromIndex(storeInstIdx) == 0 &&
-           "Store inst index already in use.");
-    
-    lis->InsertMachineInstrInMaps(storeInst, storeInstIdx);
+    if (!valno->isDefAccurate() && !valno->isPHIDef()) {
+      // Early out for values which have no well defined def point.
+      return spillIntervals;
+    }
 
-    return storeInstIdx;
-  }
+    // Ok.. we should be able to proceed...
+    const TargetRegisterClass *trc = mri->getRegClass(li->reg);
+    unsigned ss = vrm->assignVirt2StackSlot(li->reg);    
+    vrm->grow();
+    vrm->assignVirt2StackSlot(li->reg, ss);
+
+    MachineInstr *mi = 0;
+    LiveIndex storeIdx = LiveIndex();
+
+    if (valno->isDefAccurate()) {
+      // If we have an accurate def we can just grab an iterator to the instr
+      // after the def.
+      mi = lis->getInstructionFromIndex(valno->def);
+      storeIdx = lis->getDefIndex(insertStoreAfter(mi, ss, li->reg, trc));
+    } else {
+      // if we get here we have a PHI def.
+      mi = &lis->getMBBFromIndex(valno->def)->front();
+      storeIdx = lis->getDefIndex(insertStoreBefore(mi, ss, li->reg, trc));
+    }
 
-  unsigned insertLoadFor(MachineInstr *mi, unsigned ss,
-                         unsigned newVReg,
-                         const TargetRegisterClass *trc) {
-    MachineBasicBlock::iterator useInstItr(mi);
+    MachineBasicBlock *defBlock = mi->getParent();
+    LiveIndex loadIdx = LiveIndex();
 
-    makeRoomForInsertBefore(mi);
-    unsigned miIdx = lis->getInstructionIndex(mi);
-    
-    tii->loadRegFromStackSlot(*mi->getParent(), useInstItr, newVReg, ss, trc);
-    MachineBasicBlock::iterator loadInstItr(mi);
-    --loadInstItr;
-    MachineInstr *loadInst = &*loadInstItr;
-    unsigned loadInstIdx = miIdx - LiveIntervals::InstrSlots::NUM;
+    // Now we need to find the load...
+    MachineBasicBlock::iterator useItr(mi);
+    for (; !useItr->readsRegister(li->reg); ++useItr) {}
 
-    assert(lis->getInstructionFromIndex(loadInstIdx) == 0 &&
-           "Load inst index already in use.");
+    if (useItr != defBlock->end()) {
+      MachineInstr *loadInst = useItr;
+      loadIdx = lis->getUseIndex(insertLoadBefore(loadInst, ss, li->reg, trc));
+    }
+    else {
+      MachineInstr *loadInst = &defBlock->back();
+      loadIdx = lis->getUseIndex(insertLoadAfter(loadInst, ss, li->reg, trc));
+    }
 
-    lis->InsertMachineInstrInMaps(loadInst, loadInstIdx);
+    li->removeRange(storeIdx, loadIdx, true);
 
-    return loadInstIdx;
+    return spillIntervals;
   }
 
 };
 
 }
 
-
 llvm::Spiller* llvm::createSpiller(MachineFunction *mf, LiveIntervals *lis,
-                                   VirtRegMap *vrm) {
-  return new TrivialSpiller(mf, lis, vrm);
+                                   LiveStacks *ls, VirtRegMap *vrm) {
+  return new TrivialSpiller(mf, lis, ls, vrm);
 }