Inline check that's used only once.
[oota-llvm.git] / lib / CodeGen / RegAllocLinearScan.cpp
index 947a6c74bd1cb0536686121d9ebb61617c9d5978..966570f3f3362ecb9c69600a46a069c628206073 100644 (file)
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "regalloc"
+#include "LiveDebugVariables.h"
+#include "LiveRangeEdit.h"
 #include "VirtRegMap.h"
 #include "VirtRegRewriter.h"
 #include "Spiller.h"
+#include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Function.h"
 #include "llvm/CodeGen/CalcSpillWeights.h"
 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
@@ -90,6 +93,7 @@ namespace {
   struct RALinScan : public MachineFunctionPass {
     static char ID;
     RALinScan() : MachineFunctionPass(ID) {
+      initializeLiveDebugVariablesPass(*PassRegistry::getPassRegistry());
       initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
       initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry());
       initializeRegisterCoalescerAnalysisGroup(
@@ -193,6 +197,8 @@ namespace {
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
+      AU.addRequired<AliasAnalysis>();
+      AU.addPreserved<AliasAnalysis>();
       AU.addRequired<LiveIntervals>();
       AU.addPreserved<SlotIndexes>();
       if (StrongPHIElim)
@@ -209,6 +215,8 @@ namespace {
       AU.addPreserved<MachineLoopInfo>();
       AU.addRequired<VirtRegMap>();
       AU.addPreserved<VirtRegMap>();
+      AU.addRequired<LiveDebugVariables>();
+      AU.addPreserved<LiveDebugVariables>();
       AU.addRequiredID(MachineDominatorsID);
       AU.addPreservedID(MachineDominatorsID);
       MachineFunctionPass::getAnalysisUsage(AU);
@@ -367,7 +375,7 @@ namespace {
             dbgs() << str << " intervals:\n";
 
           for (; i != e; ++i) {
-            dbgs() << "\t" << *i->first << " -> ";
+            dbgs() << '\t' << *i->first << " -> ";
 
             unsigned reg = i->first->reg;
             if (TargetRegisterInfo::isVirtualRegister(reg))
@@ -382,7 +390,7 @@ namespace {
 }
 
 INITIALIZE_PASS_BEGIN(RALinScan, "linearscan-regalloc",
-                "Linear Scan Register Allocator", false, false)
+                      "Linear Scan Register Allocator", false, false)
 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
 INITIALIZE_PASS_DEPENDENCY(StrongPHIElimination)
 INITIALIZE_PASS_DEPENDENCY(CalculateSpillWeights)
@@ -391,8 +399,9 @@ INITIALIZE_PASS_DEPENDENCY(LiveStacks)
 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
 INITIALIZE_PASS_DEPENDENCY(VirtRegMap)
 INITIALIZE_AG_DEPENDENCY(RegisterCoalescer)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
 INITIALIZE_PASS_END(RALinScan, "linearscan-regalloc",
-                "Linear Scan Register Allocator", false, false)
+                    "Linear Scan Register Allocator", false, false)
 
 void RALinScan::ComputeRelatedRegClasses() {
   // First pass, add all reg classes to the union, and determine at least one
@@ -423,8 +432,12 @@ void RALinScan::ComputeRelatedRegClasses() {
     for (DenseMap<unsigned, const TargetRegisterClass*>::iterator
          I = OneClassForEachPhysReg.begin(), E = OneClassForEachPhysReg.end();
          I != E; ++I)
-      for (const unsigned *AS = tri_->getAliasSet(I->first); *AS; ++AS)
-        RelatedRegClasses.unionSets(I->second, OneClassForEachPhysReg[*AS]);
+      for (const unsigned *AS = tri_->getAliasSet(I->first); *AS; ++AS) {
+        const TargetRegisterClass *AliasClass = 
+          OneClassForEachPhysReg.lookup(*AS);
+        if (AliasClass)
+          RelatedRegClasses.unionSets(I->second, AliasClass);
+      }
 }
 
 /// attemptTrivialCoalescing - If a simple interval is defined by a copy, try
@@ -446,7 +459,7 @@ unsigned RALinScan::attemptTrivialCoalescing(LiveInterval &cur, unsigned Reg) {
   const LiveRange &range = cur.ranges.front();
 
   VNInfo *vni = range.valno;
-  if (vni->isUnused())
+  if (vni->isUnused() || !vni->def.isValid())
     return Reg;
 
   unsigned CandReg;
@@ -462,6 +475,10 @@ unsigned RALinScan::attemptTrivialCoalescing(LiveInterval &cur, unsigned Reg) {
       CandReg = CopyMI->getOperand(0).getReg();
     else
       return Reg;
+
+    // If the target of the copy is a sub-register then don't coalesce.
+    if(CopyMI->getOperand(0).getSubReg())
+      return Reg;
   }
 
   if (TargetRegisterInfo::isVirtualRegister(CandReg)) {
@@ -524,6 +541,9 @@ bool RALinScan::runOnMachineFunction(MachineFunction &fn) {
   // Rewrite spill code and update the PhysRegsUsed set.
   rewriter_->runOnMachineFunction(*mf_, *vrm_, li_);
 
+  // Write out new DBG_VALUE instructions.
+  getAnalysis<LiveDebugVariables>().emitDebugValues(vrm_);
+
   assert(unhandled_.empty() && "Unhandled live intervals remain!");
 
   finalizeRegUses();
@@ -918,13 +938,9 @@ LiveInterval *RALinScan::hasNextReloadInterval(LiveInterval *cur) {
 }
 
 void RALinScan::DowngradeRegister(LiveInterval *li, unsigned Reg) {
-  bool isNew = DowngradedRegs.insert(Reg);
-  isNew = isNew; // Silence compiler warning.
-  assert(isNew && "Multiple reloads holding the same register?");
-  DowngradeMap.insert(std::make_pair(li->reg, Reg));
-  for (const unsigned *AS = tri_->getAliasSet(Reg); *AS; ++AS) {
-    isNew = DowngradedRegs.insert(*AS);
-    isNew = isNew; // Silence compiler warning.
+  for (const unsigned *AS = tri_->getOverlaps(Reg); *AS; ++AS) {
+    bool isNew = DowngradedRegs.insert(*AS);
+    (void)isNew; // Silence compiler warning.
     assert(isNew && "Multiple reloads holding the same register?");
     DowngradeMap.insert(std::make_pair(li->reg, *AS));
   }
@@ -950,10 +966,11 @@ namespace {
 /// assignRegOrStackSlotAtInterval - assign a register if one is available, or
 /// spill.
 void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
-  DEBUG(dbgs() << "\tallocating current interval: ");
+  const TargetRegisterClass *RC = mri_->getRegClass(cur->reg);
+  DEBUG(dbgs() << "\tallocating current interval from "
+               << RC->getName() << ": ");
 
   // This is an implicitly defined live interval, just assign any register.
-  const TargetRegisterClass *RC = mri_->getRegClass(cur->reg);
   if (cur->empty()) {
     unsigned physReg = vrm_->getRegAllocPref(cur->reg);
     if (!physReg)
@@ -977,7 +994,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
   // one, e.g. X86::mov32to32_. These move instructions are not coalescable.
   if (!vrm_->getRegAllocPref(cur->reg) && cur->hasAtLeastOneValue()) {
     VNInfo *vni = cur->begin()->valno;
-    if (!vni->isUnused()) {
+    if (!vni->isUnused() && vni->def.isValid()) {
       MachineInstr *CopyMI = li_->getInstructionFromIndex(vni->def);
       if (CopyMI && CopyMI->isCopy()) {
         unsigned DstSubReg = CopyMI->getOperand(0).getSubReg();
@@ -1093,6 +1110,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
   // list.
   if (physReg) {
     DEBUG(dbgs() <<  tri_->getName(physReg) << '\n');
+    assert(RC->contains(physReg) && "Invalid candidate");
     vrm_->assignVirt2Phys(cur->reg, physReg);
     addRegUse(physReg);
     active_.push_back(std::make_pair(cur, cur->begin()));
@@ -1213,8 +1231,9 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
   // linearscan.
   if (cur->weight != HUGE_VALF && cur->weight <= minWeight) {
     DEBUG(dbgs() << "\t\t\tspilling(c): " << *cur << '\n');
-    SmallVector<LiveInterval*, 8> spillIs, added;
-    spiller_->spill(cur, added, spillIs);
+    SmallVector<LiveInterval*, 8> added;
+    LiveRangeEdit LRE(*cur, added);
+    spiller_->spill(LRE);
 
     std::sort(added.begin(), added.end(), LISorter());
     if (added.empty())
@@ -1290,7 +1309,8 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
     DEBUG(dbgs() << "\t\t\tspilling(a): " << *sli << '\n');
     if (sli->beginIndex() < earliestStart)
       earliestStart = sli->beginIndex();
-    spiller_->spill(sli, added, spillIs);
+    LiveRangeEdit LRE(*sli, added, 0, &spillIs);
+    spiller_->spill(LRE);
     spilled.insert(sli->reg);
   }
 
@@ -1409,8 +1429,7 @@ unsigned RALinScan::getFreePhysReg(LiveInterval* cur,
   std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(cur->reg);
   // Resolve second part of the hint (if possible) given the current allocation.
   unsigned physReg = Hint.second;
-  if (physReg &&
-      TargetRegisterInfo::isVirtualRegister(physReg) && vrm_->hasPhys(physReg))
+  if (TargetRegisterInfo::isVirtualRegister(physReg) && vrm_->hasPhys(physReg))
     physReg = vrm_->getPhys(physReg);
 
   TargetRegisterClass::iterator I, E;