X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FInlineSpiller.cpp;h=b63611b94c1c1d403d38d9160a6dac9fe77d837e;hb=cccfd194ecf8e1c6fb203ec3f96aca8cfe9e0484;hp=0c46aeb6aa1c8f15646bf776c08eae555f209252;hpb=6b6e32d954233ddeeae7f99e358ff85059f1176a;p=oota-llvm.git

diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index 0c46aeb6aa1..b63611b94c1 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -28,22 +28,26 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
 STATISTIC(NumSpilledRanges,   "Number of spilled live ranges");
-STATISTIC(NumSnippets,        "Number of snippets included in spills");
+STATISTIC(NumSnippets,        "Number of spilled snippets");
 STATISTIC(NumSpills,          "Number of spills inserted");
+STATISTIC(NumSpillsRemoved,   "Number of spills removed");
 STATISTIC(NumReloads,         "Number of reloads inserted");
+STATISTIC(NumReloadsRemoved,  "Number of reloads removed");
 STATISTIC(NumFolded,          "Number of folded stack accesses");
 STATISTIC(NumFoldedLoads,     "Number of folded loads");
 STATISTIC(NumRemats,          "Number of rematerialized defs for spilling");
-STATISTIC(NumOmitReloadSpill, "Number of omitted spills after reloads");
-STATISTIC(NumHoistLocal,      "Number of locally hoisted spills");
-STATISTIC(NumHoistGlobal,     "Number of globally hoisted spills");
-STATISTIC(NumRedundantSpills, "Number of redundant spills identified");
+STATISTIC(NumOmitReloadSpill, "Number of omitted spills of reloads");
+STATISTIC(NumHoists,          "Number of hoisted spills");
+
+static cl::opt<bool> DisableHoisting("disable-spill-hoist", cl::Hidden,
+                                     cl::desc("Disable inline spill hoisting"));
 
 namespace {
 class InlineSpiller : public Spiller {
@@ -86,6 +90,9 @@ public:
     // True when value is defined by an original PHI not from splitting.
     bool DefByOrigPHI;
 
+    // True when the COPY defining this value killed its source.
+    bool KillsSource;
+
     // The preferred register to spill.
     unsigned SpillReg;
 
@@ -108,7 +115,7 @@ public:
     TinyPtrVector<VNInfo*> Deps;
 
     SibValueInfo(unsigned Reg, VNInfo *VNI)
-      : AllDefsAreReloads(true), DefByOrigPHI(false),
+      : AllDefsAreReloads(true), DefByOrigPHI(false), KillsSource(false),
         SpillReg(Reg), SpillVNI(VNI), SpillMBB(0), DefMI(0) {}
 
     // Returns true when a def has been found.
@@ -315,6 +322,8 @@ static raw_ostream &operator<<(raw_ostream &OS,
     OS << " all-reloads";
   if (SVI.DefByOrigPHI)
     OS << " orig-phi";
+  if (SVI.KillsSource)
+    OS << " kill";
   OS << " deps[";
   for (unsigned i = 0, e = SVI.Deps.size(); i != e; ++i)
     OS << ' ' << SVI.Deps[i]->id << '@' << SVI.Deps[i]->def;
@@ -367,7 +376,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI,
 
     // Should this value be propagated as a preferred spill candidate?  We don't
     // propagate values of registers that are about to spill.
-    bool PropSpill = !isRegToSpill(SV.SpillReg);
+    bool PropSpill = !DisableHoisting && !isRegToSpill(SV.SpillReg);
     unsigned SpillDepth = ~0u;
 
     for (TinyPtrVector<VNInfo*>::iterator DepI = Deps->begin(),
@@ -398,7 +407,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI,
       if (PropSpill && SV.SpillVNI != DepSV.SpillVNI) {
         if (SV.SpillMBB == DepSV.SpillMBB) {
           // DepSV is in the same block.  Hoist when dominated.
-          if (SV.SpillVNI->def < DepSV.SpillVNI->def) {
+          if (DepSV.KillsSource && SV.SpillVNI->def < DepSV.SpillVNI->def) {
             // This is an alternative def earlier in the same MBB.
             // Hoist the spill as far as possible in SpillMBB. This can ease
             // register pressure:
@@ -414,6 +423,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI,
             //   spill x
             //   y = use x<kill>
             //
+            // This hoist only helps when the DepSV copy kills its source.
             Changed = true;
             DepSV.SpillReg = SV.SpillReg;
             DepSV.SpillVNI = SV.SpillVNI;
@@ -568,10 +578,14 @@ MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI,
     if (unsigned SrcReg = isFullCopyOf(MI, Reg)) {
       if (isSibling(SrcReg)) {
         LiveInterval &SrcLI = LIS.getInterval(SrcReg);
-        VNInfo *SrcVNI = SrcLI.getVNInfoAt(VNI->def.getUseIndex());
-        assert(SrcVNI && "Copy from non-existing value");
+        LiveRange *SrcLR = SrcLI.getLiveRangeContaining(VNI->def.getUseIndex());
+        assert(SrcLR && "Copy from non-existing value");
+        // Check if this COPY kills its source.
+        SVI->second.KillsSource = (SrcLR->end == VNI->def);
+        VNInfo *SrcVNI = SrcLR->valno;
         DEBUG(dbgs() << "copy of " << PrintReg(SrcReg) << ':'
-                     << SrcVNI->id << '@' << SrcVNI->def << '\n');
+                     << SrcVNI->id << '@' << SrcVNI->def
+                     << " kill=" << unsigned(SVI->second.KillsSource) << '\n');
         // Known sibling source value? Try an insertion.
         tie(SVI, Inserted) = SibValues.insert(std::make_pair(SrcVNI,
                                                  SibValueInfo(SrcReg, SrcVNI)));
@@ -715,10 +729,8 @@ bool InlineSpiller::hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI) {
   VRM.addSpillSlotUse(StackSlot, MII);
   DEBUG(dbgs() << "\thoisted: " << SVI.SpillVNI->def << '\t' << *MII);
 
-  if (MBB == CopyMI->getParent())
-    ++NumHoistLocal;
-  else
-    ++NumHoistGlobal;
+  ++NumSpills;
+  ++NumHoists;
   return true;
 }
 
@@ -773,7 +785,8 @@ void InlineSpiller::eliminateRedundantSpills(LiveInterval &SLI, VNInfo *VNI) {
         // eliminateDeadDefs won't normally remove stores, so switch opcode.
         MI->setDesc(TII.get(TargetOpcode::KILL));
         DeadDefs.push_back(MI);
-        ++NumRedundantSpills;
+        ++NumSpillsRemoved;
+        --NumSpills;
       }
     }
   } while (!WorkList.empty());
@@ -971,10 +984,10 @@ void InlineSpiller::reMaterializeAll() {
 /// If MI is a load or store of StackSlot, it can be removed.
 bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) {
   int FI = 0;
-  unsigned InstrReg;
-  if (!(InstrReg = TII.isLoadFromStackSlot(MI, FI)) &&
-      !(InstrReg = TII.isStoreToStackSlot(MI, FI)))
-    return false;
+  unsigned InstrReg = TII.isLoadFromStackSlot(MI, FI);
+  bool IsLoad = InstrReg;
+  if (!IsLoad)
+    InstrReg = TII.isStoreToStackSlot(MI, FI);
 
   // We have a stack access. Is it the right register and slot?
   if (InstrReg != Reg || FI != StackSlot)
@@ -983,6 +996,15 @@ bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) {
   DEBUG(dbgs() << "Coalescing stack access: " << *MI);
   LIS.RemoveMachineInstrFromMaps(MI);
   MI->eraseFromParent();
+
+  if (IsLoad) {
+    ++NumReloadsRemoved;
+    --NumReloads;
+  } else {
+    ++NumSpillsRemoved;
+    --NumSpills;
+  }
+
   return true;
 }
 
@@ -994,6 +1016,7 @@ bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) {
 bool InlineSpiller::foldMemoryOperand(MachineBasicBlock::iterator MI,
                                       const SmallVectorImpl<unsigned> &Ops,
                                       MachineInstr *LoadMI) {
+  bool WasCopy = MI->isCopy();
   // TargetInstrInfo::foldMemoryOperand only expects explicit, non-tied
   // operands.
   SmallVector<unsigned, 8> FoldOps;
@@ -1023,7 +1046,12 @@ bool InlineSpiller::foldMemoryOperand(MachineBasicBlock::iterator MI,
     VRM.addSpillSlotUse(StackSlot, FoldMI);
   MI->eraseFromParent();
   DEBUG(dbgs() << "\tfolded: " << *FoldMI);
-  ++NumFolded;
+  if (!WasCopy)
+    ++NumFolded;
+  else if (Ops.front() == 0)
+    ++NumSpills;
+  else
+    ++NumReloads;
   return true;
 }