Update to in-place spilling framework. Includes live interval scaling and trivial rewriter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72729 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 366 insertions, 104 deletions

diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 9dee892c75..67120b8798 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -359,6 +359,29 @@ void LiveInterval::removeValNo(VNInfo *ValNo) {
   }
 }
  
+/// scaleNumbering - Renumber VNI and ranges to provide gaps for new
+/// instructions.                                                   
+void LiveInterval::scaleNumbering(unsigned factor) {
+  // Scale ranges.                                                            
+  for (iterator RI = begin(), RE = end(); RI != RE; ++RI) {
+    RI->start = InstrSlots::scale(RI->start, factor);
+    RI->end = InstrSlots::scale(RI->end, factor);
+  }
+
+  // Scale VNI info.                                                          
+  for (vni_iterator VNI = vni_begin(), VNIE = vni_end(); VNI != VNIE; ++VNI) {
+    VNInfo *vni = *VNI;
+    if (vni->def != ~0U && vni->def != ~1U) {
+      vni->def = InstrSlots::scale(vni->def, factor);
+    }
+
+    for (unsigned i = 0; i < vni->kills.size(); ++i) {
+      if (vni->kills[i] != 0)
+        vni->kills[i] = InstrSlots::scale(vni->kills[i], factor);
+    }
+  }
+}
+
 /// getLiveRangeContaining - Return the live range that contains the
 /// specified index, or null if there is none.
 LiveInterval::const_iterator 
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index bf18015e96..cf0a648b62 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -36,6 +36,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
 #include <algorithm>
+#include <limits>
 #include <cmath>
 using namespace llvm;
 
@@ -243,6 +244,49 @@ void LiveIntervals::computeNumbering() {
     }
 }
 
+void LiveIntervals::scaleNumbering(int factor) {
+  // Need to
+  //  * scale MBB begin and end points
+  //  * scale all ranges.
+  //  * Update VNI structures.
+  //  * Scale instruction numberings 
+
+  // Scale the MBB indices.
+  Idx2MBBMap.clear();
+  for (MachineFunction::iterator MBB = mf_->begin(), MBBE = mf_->end();
+       MBB != MBBE; ++MBB) {
+    std::pair<unsigned, unsigned> &mbbIndices = MBB2IdxMap[MBB->getNumber()];
+    mbbIndices.first = InstrSlots::scale(mbbIndices.first, factor);
+    mbbIndices.second = InstrSlots::scale(mbbIndices.second, factor);
+    Idx2MBBMap.push_back(std::make_pair(mbbIndices.first, MBB)); 
+  }
+  std::sort(Idx2MBBMap.begin(), Idx2MBBMap.end(), Idx2MBBCompare());
+
+  // Scale the intervals.
+  for (iterator LI = begin(), LE = end(); LI != LE; ++LI) {
+    LI->second->scaleNumbering(factor);
+  }
+
+  // Scale MachineInstrs.
+  Mi2IndexMap oldmi2iMap = mi2iMap_;
+  unsigned highestSlot = 0;
+  for (Mi2IndexMap::iterator MI = oldmi2iMap.begin(), ME = oldmi2iMap.end();
+       MI != ME; ++MI) {
+    unsigned newSlot = InstrSlots::scale(MI->second, factor);
+    mi2iMap_[MI->first] = newSlot;
+    highestSlot = std::max(highestSlot, newSlot); 
+  }
+
+  i2miMap_.clear();
+  i2miMap_.resize(highestSlot + 1);
+  for (Mi2IndexMap::iterator MI = mi2iMap_.begin(), ME = mi2iMap_.end();
+       MI != ME; ++MI) {
+    i2miMap_[MI->second] = MI->first;
+  }
+
+}
+
+
 /// runOnMachineFunction - Register allocate the whole function
 ///
 bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
diff --git a/lib/CodeGen/LiveStackAnalysis.cpp b/lib/CodeGen/LiveStackAnalysis.cpp
index c68a2d9a80..86f7ea20c9 100644
--- a/lib/CodeGen/LiveStackAnalysis.cpp
+++ b/lib/CodeGen/LiveStackAnalysis.cpp
@@ -15,15 +15,24 @@
 
 #define DEBUG_TYPE "livestacks"
 #include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/ADT/Statistic.h"
+#include <limits>
 using namespace llvm;
 
 char LiveStacks::ID = 0;
 static RegisterPass<LiveStacks> X("livestacks", "Live Stack Slot Analysis");
 
+void LiveStacks::scaleNumbering(int factor) {
+  // Scale the intervals.
+  for (iterator LI = begin(), LE = end(); LI != LE; ++LI) {
+    LI->second.scaleNumbering(factor);
+  }
+}
+
 void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
   MachineFunctionPass::getAnalysisUsage(AU);
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index ac6ab32341..ee118de4f4 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -40,6 +40,8 @@
 #include <queue>
 #include <memory>
 #include <cmath>
+#include <iostream>
+
 using namespace llvm;
 
 STATISTIC(NumIters     , "Number of iterations performed");
@@ -310,6 +312,93 @@ namespace {
 static RegisterPass<RALinScan>
 X("linearscan-regalloc", "Linear Scan Register Allocator");
 
+bool validateRegAlloc(MachineFunction *mf, LiveIntervals *lis,
+                      VirtRegMap *vrm) {
+
+  MachineRegisterInfo *mri = &mf->getRegInfo();
+  const TargetRegisterInfo *tri = mf->getTarget().getRegisterInfo();
+  bool allocationValid = true;
+
+
+  for (LiveIntervals::iterator itr = lis->begin(), end = lis->end();
+       itr != end; ++itr) {
+
+    LiveInterval *li = itr->second;
+
+    if (TargetRegisterInfo::isPhysicalRegister(li->reg)) {
+      continue;
+    }
+
+    if (vrm->hasPhys(li->reg)) {
+      const TargetRegisterClass *trc = mri->getRegClass(li->reg);
+      
+      if (lis->hasInterval(vrm->getPhys(li->reg))) {
+        if (li->overlaps(lis->getInterval(vrm->getPhys(li->reg)))) {
+          std::cerr << "vreg " << li->reg << " overlaps its assigned preg "
+                    << vrm->getPhys(li->reg) << "(" << tri->getName(vrm->getPhys(li->reg)) << ")\n";
+        }
+      }
+
+      TargetRegisterClass::iterator fReg =
+        std::find(trc->allocation_order_begin(*mf), trc->allocation_order_end(*mf),
+                  vrm->getPhys(li->reg));
+
+      if (fReg == trc->allocation_order_end(*mf)) {
+        std::cerr << "preg " << vrm->getPhys(li->reg) 
+                  << "(" << tri->getName(vrm->getPhys(li->reg)) << ") is not in the allocation set for vreg "
+                  << li->reg << "\n";
+        allocationValid &= false;
+      }
+    }
+    else {
+      std::cerr << "No preg for vreg " << li->reg << "\n";
+      // What about conflicting loads/stores?
+      continue;
+    }
+
+    for (LiveIntervals::iterator itr2 = next(itr); itr2 != end; ++itr2) {
+
+      LiveInterval *li2 = itr2->second;
+
+      if (li2->empty())
+        continue;
+
+      if (TargetRegisterInfo::isPhysicalRegister(li2->reg)) {
+        if (li->overlaps(*li2)) {
+          if (vrm->getPhys(li->reg) == li2->reg ||
+              tri->areAliases(vrm->getPhys(li->reg), li2->reg)) {
+            std::cerr << "vreg " << li->reg << " overlaps preg "
+                      << li2->reg << "(" << tri->getName(li2->reg) << ") which aliases "
+                      << vrm->getPhys(li->reg) << "(" << tri->getName(vrm->getPhys(li->reg)) << ")\n";
+            allocationValid &= false;
+          }
+        }
+      }
+      else {
+
+        if (!vrm->hasPhys(li2->reg)) {
+          continue;
+        }
+
+        if (li->overlaps(*li2)) {
+          if (vrm->getPhys(li->reg) == vrm->getPhys(li2->reg) ||
+              tri->areAliases(vrm->getPhys(li->reg), vrm->getPhys(li2->reg))) {
+            std::cerr << "vreg " << li->reg << " (preg " << vrm->getPhys(li->reg)
+                      << ") overlaps vreg " << li2->reg << " (preg " << vrm->getPhys(li2->reg)
+                      << ") and " << vrm->getPhys(li->reg) << " aliases " << vrm->getPhys(li2->reg) << "\n";
+            allocationValid &= false;
+          } 
+        }
+      }
+    } 
+
+  } 
+
+  return allocationValid;
+
+}
+
+
 void RALinScan::ComputeRelatedRegClasses() {
   // First pass, add all reg classes to the union, and determine at least one
   // reg class that each register is in.
@@ -430,16 +519,17 @@ bool RALinScan::runOnMachineFunction(MachineFunction &fn) {
   if (!rewriter_.get()) rewriter_.reset(createVirtRegRewriter());
   
   if (NewSpillFramework) {
-    spiller_.reset(createSpiller(mf_, li_, vrm_));
-  }
-  else {
-    spiller_.reset(0);
+    spiller_.reset(createSpiller(mf_, li_, ls_, vrm_));
   }
-
+  
   initIntervalSets();
 
   linearScan();
 
+  if (NewSpillFramework) {
+    bool allocValid = validateRegAlloc(mf_, li_, vrm_);
+  }
+
   // Rewrite spill code and update the PhysRegsUsed set.
   rewriter_->runOnMachineFunction(*mf_, *vrm_, li_);
 
@@ -454,6 +544,7 @@ bool RALinScan::runOnMachineFunction(MachineFunction &fn) {
   NextReloadMap.clear();
   DowngradedRegs.clear();
   DowngradeMap.clear();
+  spiller_.reset(0);
 
   return true;
 }
@@ -1127,8 +1218,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
     
     if (!NewSpillFramework) {
       added = li_->addIntervalsForSpills(*cur, spillIs, loopInfo, *vrm_);
-    }
-    else {
+    } else {
       added = spiller_->spill(cur); 
     }
 
@@ -1192,7 +1282,9 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
 
   // The earliest start of a Spilled interval indicates up to where
   // in handled we need to roll back
+  
   unsigned earliestStart = cur->beginNumber();
+  LiveInterval *earliestStartInterval = cur;
 
   // Spill live intervals of virtual regs mapped to the physical register we
   // want to clear (and its aliases).  We only spill those that overlap with the
@@ -1201,17 +1293,48 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
   // mark our rollback point.
   std::vector<LiveInterval*> added;
   while (!spillIs.empty()) {
+    bool epicFail = false;
     LiveInterval *sli = spillIs.back();
     spillIs.pop_back();
     DOUT << "\t\t\tspilling(a): " << *sli << '\n';
     earliestStart = std::min(earliestStart, sli->beginNumber());
-    std::vector<LiveInterval*> newIs =
-      li_->addIntervalsForSpills(*sli, spillIs, loopInfo, *vrm_);
+    earliestStartInterval =
+      (earliestStartInterval->beginNumber() < sli->beginNumber()) ?
+         earliestStartInterval : sli;
+    
+    if (earliestStartInterval->beginNumber()!=earliestStart) {
+      epicFail |= true;
+      std::cerr << "What the 1 - "
+      		<< "earliestStart = " << earliestStart
+      		<< "earliestStartInterval = " << earliestStartInterval->beginNumber()
+      		<< "\n";
+    }
+   
+    std::vector<LiveInterval*> newIs;
+    if (!NewSpillFramework) {
+      newIs = li_->addIntervalsForSpills(*sli, spillIs, loopInfo, *vrm_);
+    } else {
+      newIs = spiller_->spill(sli);
+    }
     addStackInterval(sli, ls_, li_, mri_, *vrm_);
     std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
     spilled.insert(sli->reg);
+
+    if (earliestStartInterval->beginNumber()!=earliestStart) {
+      epicFail |= true;
+      std::cerr << "What the 2 - "
+      		<< "earliestStart = " << earliestStart
+      		<< "earliestStartInterval = " << earliestStartInterval->beginNumber()
+      		<< "\n";
+    }
+
+    if (epicFail) {
+      //abort();
+    }
   }
 
+  earliestStart = earliestStartInterval->beginNumber();
+
   DOUT << "\t\trolling back to: " << earliestStart << '\n';
 
   // Scan handled in reverse order up to the earliest start of a
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index a7807f130e..2bc234f7d0 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -2598,7 +2598,7 @@ void SimpleRegisterCoalescing::releaseMemory() {
 static bool isZeroLengthInterval(LiveInterval *li) {
   for (LiveInterval::Ranges::const_iterator
          i = li->ranges.begin(), e = li->ranges.end(); i != e; ++i)
-    if (i->end - i->start > LiveIntervals::InstrSlots::NUM)
+    if (i->end - i->start > LiveInterval::InstrSlots::NUM)
       return false;
   return true;
 }
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h
index d8ff2dc152..a495bfd644 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.h
+++ b/lib/CodeGen/SimpleRegisterCoalescing.h
@@ -133,7 +133,7 @@ namespace llvm {
       if (!li_->hasInterval(Reg))
         return 0;
       return li_->getApproximateInstructionCount(li_->getInterval(Reg)) *
-             LiveIntervals::InstrSlots::NUM;
+             LiveInterval::InstrSlots::NUM;
     }
 
     /// print - Implement the dump method.
diff --git a/lib/CodeGen/Spiller.cpp b/lib/CodeGen/Spiller.cpp
index eb2a8a10b2..ce63121251 100644
--- a/lib/CodeGen/Spiller.cpp
+++ b/lib/CodeGen/Spiller.cpp
@@ -12,6 +12,7 @@
 #include "Spiller.h"
 #include "VirtRegMap.h"
 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/LiveStackAnalysis.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -19,28 +20,105 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Support/Debug.h"
 
-#include <algorithm>
-#include <map>
-
 using namespace llvm;
 
 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) {
+  /// 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.
+  unsigned insertStoreFor(MachineInstr *mi, unsigned ss,
+                          unsigned newVReg,
+                          const TargetRegisterClass *trc) {
+    MachineBasicBlock::iterator nextInstItr(mi); 
+    ++nextInstItr;
+
+    if (!lis->hasGapAfterInstr(lis->getInstructionIndex(mi))) {
+      lis->scaleNumbering(2);
+      ls->scaleNumbering(2);
+    }
+
+    unsigned miIdx = lis->getInstructionIndex(mi);
+
+    assert(lis->hasGapAfterInstr(miIdx));
+
+    tii->storeRegToStackSlot(*mi->getParent(), nextInstItr, newVReg,
+                             true, ss, trc);
+    MachineBasicBlock::iterator storeInstItr(mi);
+    ++storeInstItr;
+    MachineInstr *storeInst = &*storeInstItr;
+    unsigned storeInstIdx = miIdx + LiveInterval::InstrSlots::NUM;
+
+    assert(lis->getInstructionFromIndex(storeInstIdx) == 0 &&
+           "Store inst index already in use.");
+    
+    lis->InsertMachineInstrInMaps(storeInst, storeInstIdx);
+
+    return storeInstIdx;
+  }
+
+  /// Insert a load of the given veg 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.
+  unsigned insertLoadFor(MachineInstr *mi, unsigned ss,
+                         unsigned newVReg,
+                         const TargetRegisterClass *trc) {
+    MachineBasicBlock::iterator useInstItr(mi);
+
+    if (!lis->hasGapBeforeInstr(lis->getInstructionIndex(mi))) {
+      lis->scaleNumbering(2);
+      ls->scaleNumbering(2);
+    }
+
+    unsigned miIdx = lis->getInstructionIndex(mi);
+
+    assert(lis->hasGapBeforeInstr(miIdx));
+    
+    tii->loadRegFromStackSlot(*mi->getParent(), useInstItr, newVReg, ss, trc);
+    MachineBasicBlock::iterator loadInstItr(mi);
+    --loadInstItr;
+    MachineInstr *loadInst = &*loadInstItr;
+    unsigned loadInstIdx = miIdx - LiveInterval::InstrSlots::NUM;
+
+    assert(lis->getInstructionFromIndex(loadInstIdx) == 0 &&
+           "Load inst index already in use.");
+
+    lis->InsertMachineInstrInMaps(loadInst, loadInstIdx);
+
+    return loadInstIdx;
+  }
 
-    DOUT << "Trivial spiller spilling " << *li << "\n";
+
+  /// 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) {
+    DOUT << "Spilling everywhere " << *li << "\n";
 
     assert(li->weight != HUGE_VALF &&
            "Attempting to spill already spilled value.");
@@ -51,16 +129,16 @@ public:
     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;
-
+      do {
+        ++regItr;
+      } while (regItr != mri->reg_end() && (&*regItr == mi));
+      
       SmallVector<unsigned, 2> indices;
       bool hasUse = false;
       bool hasDef = false;
@@ -78,12 +156,12 @@ 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);
 
@@ -92,6 +170,8 @@ public:
         }
       }
 
+      assert(hasUse || hasDef);
+
       if (hasUse) {
         unsigned loadInstIdx = insertLoadFor(mi, ss, newVReg, trc);
         unsigned start = lis->getDefIndex(loadInstIdx),
@@ -103,7 +183,6 @@ public:
         LiveRange lr(start, end, vni);
 
         newLI->addRange(lr);
-        added.push_back(newLI);
       }
 
       if (hasDef) {
@@ -117,90 +196,34 @@ public:
         LiveRange lr(start, end, vni);
       
         newLI->addRange(lr);
-        added.push_back(newLI);
       }
 
-      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;
-
-
-
-  void makeRoomForInsertBefore(MachineInstr *mi) {
-    if (!lis->hasGapBeforeInstr(lis->getInstructionIndex(mi))) {
-      lis->computeNumbering();
-    }
-
-    assert(lis->hasGapBeforeInstr(lis->getInstructionIndex(mi)));
-  }
-
-  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;
-
-    assert(lis->getInstructionFromIndex(storeInstIdx) == 0 &&
-           "Store inst index already in use.");
-    
-    lis->InsertMachineInstrInMaps(storeInst, storeInstIdx);
-
-    return storeInstIdx;
-  }
-
-  unsigned insertLoadFor(MachineInstr *mi, unsigned ss,
-                         unsigned newVReg,
-                         const TargetRegisterClass *trc) {
-    MachineBasicBlock::iterator useInstItr(mi);
-
-    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;
 
-    assert(lis->getInstructionFromIndex(loadInstIdx) == 0 &&
-           "Load inst index already in use.");
-
-    lis->InsertMachineInstrInMaps(loadInst, loadInstIdx);
+/// Spills any live range using the spill-everywhere method with no attempt at
+/// folding.
+class TrivialSpiller : public SpillerBase {
+public:
+  TrivialSpiller(MachineFunction *mf, LiveIntervals *lis, LiveStacks *ls, VirtRegMap *vrm) :
+    SpillerBase(mf, lis, ls, vrm) {}
 
-    return loadInstIdx;
+  std::vector<LiveInterval*> spill(LiveInterval *li) {
+    return trivialSpillEverywhere(li);
   }
 
 };
 
 }
 
-
 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);
 }
diff --git a/lib/CodeGen/Spiller.h b/lib/CodeGen/Spiller.h
index 730419b057..cad054d744 100644
--- a/lib/CodeGen/Spiller.h
+++ b/lib/CodeGen/Spiller.h
@@ -13,8 +13,9 @@
 #include <vector>
 
 namespace llvm {
-  struct LiveInterval;
+  class LiveInterval;
   class LiveIntervals;
+  class LiveStacks;
   class MachineFunction;
   class VirtRegMap;
 
@@ -30,7 +31,7 @@ namespace llvm {
 
   /// Create and return a spiller object, as specified on the command line.
   Spiller* createSpiller(MachineFunction *mf, LiveIntervals *li,
-                         VirtRegMap *vrm);
+                         LiveStacks *ls, VirtRegMap *vrm);
 }
 
 #endif
diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index 5d7bc23694..a2c12554f3 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -1027,7 +1027,7 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
         if (MBB != PInstr->getParent() &&
             InputI.liveAt(LI.getMBBStartIdx(PInstr->getParent())) &&
             InputI.expiredAt(LI.getInstructionIndex(PInstr) + 
-                             LiveIntervals::InstrSlots::NUM))
+                             LiveInterval::InstrSlots::NUM))
           InputI.removeRange(LI.getMBBStartIdx(PInstr->getParent()),
                              LI.getInstructionIndex(PInstr),
                              true);
diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp
index 36d1697549..b4c8bc1297 100644
--- a/lib/CodeGen/VirtRegRewriter.cpp
+++ b/lib/CodeGen/VirtRegRewriter.cpp
@@ -33,15 +33,16 @@ STATISTIC(NumSUnfold , "Number of stores unfolded");
 STATISTIC(NumModRefUnfold, "Number of modref unfolded");
 
 namespace {
-  enum RewriterName { simple, local };
+  enum RewriterName { simple, local, trivial };
 }
 
 static cl::opt<RewriterName>
 RewriterOpt("rewriter",
             cl::desc("Rewriter to use: (default: local)"),
             cl::Prefix,
-            cl::values(clEnumVal(simple, "simple rewriter"),
-                       clEnumVal(local,  "local rewriter"),
+            cl::values(clEnumVal(simple,  "simple rewriter"),
+                       clEnumVal(local,   "local rewriter"),
+                       clEnumVal(trivial, "trivial rewriter"),
                        clEnumValEnd),
             cl::init(local));
 
@@ -126,6 +127,42 @@ struct VISIBILITY_HIDDEN SimpleRewriter : public VirtRegRewriter {
 
 };
  
+/// This class is intended for use with the new spilling framework only. It
+/// rewrites vreg def/uses to use the assigned preg, but does not insert any
+/// spill code.
+struct VISIBILITY_HIDDEN TrivialRewriter : public VirtRegRewriter {
+
+  bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM,
+                            LiveIntervals* LIs) {
+    DOUT << "********** REWRITE MACHINE CODE **********\n";
+    DOUT << "********** Function: " << MF.getFunction()->getName() << '\n';
+    MachineRegisterInfo *mri = &MF.getRegInfo();
+
+    bool changed = false;
+
+    for (LiveIntervals::iterator liItr = LIs->begin(), liEnd = LIs->end();
+         liItr != liEnd; ++liItr) {
+
+      if (TargetRegisterInfo::isVirtualRegister(liItr->first)) {
+        if (VRM.hasPhys(liItr->first)) {
+          unsigned preg = VRM.getPhys(liItr->first);
+          mri->replaceRegWith(liItr->first, preg);
+          mri->setPhysRegUsed(preg);
+          changed = true;
+        }
+      }
+      else {
+        if (!liItr->second->empty()) {
+          mri->setPhysRegUsed(liItr->first);
+        }
+      }
+    }
+    
+    return changed;
+  }
+
+};
+
 // ************************************************************************ //
 
 /// AvailableSpills - As the local rewriter is scanning and rewriting an MBB
@@ -2182,5 +2219,7 @@ llvm::VirtRegRewriter* llvm::createVirtRegRewriter() {
     return new LocalRewriter();
   case simple:
     return new SimpleRewriter();
+  case trivial:
+    return new TrivialRewriter();
   }
 }