X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegisterScavenging.cpp;h=b8ef6a47c7dcf98e93653fbcf0eefbb04f3c0758;hb=0fbaa378737e94afba25e88363b2c4d6b7208995;hp=d0d30e8f946d49b5d8659d46ee0985802d424ea2;hpb=9b294d4056f47bac5985de89c847aa1a04d38bf0;p=oota-llvm.git

diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index d0d30e8f946..b8ef6a47c7d 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -31,9 +31,8 @@ using namespace llvm;
 
 /// setUsed - Set the register and its sub-registers as being used.
 void RegScavenger::setUsed(unsigned Reg) {
-  RegsAvailable.reset(Reg);
-
-  for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+  for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
+       SubRegs.isValid(); ++SubRegs)
     RegsAvailable.reset(*SubRegs);
 }
 
@@ -45,8 +44,11 @@ bool RegScavenger::isAliasUsed(unsigned Reg) const {
 }
 
 void RegScavenger::initRegState() {
-  ScavengedReg = 0;
-  ScavengeRestore = NULL;
+  for (SmallVector<ScavengedInfo, 2>::iterator I = Scavenged.begin(),
+       IE = Scavenged.end(); I != IE; ++I) {
+    I->Reg = 0;
+    I->Restore = NULL;
+  }
 
   // All registers started out unused.
   RegsAvailable.set();
@@ -102,31 +104,16 @@ void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
 }
 
 void RegScavenger::addRegWithSubRegs(BitVector &BV, unsigned Reg) {
-  BV.set(Reg);
-  for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+  for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
+       SubRegs.isValid(); ++SubRegs)
     BV.set(*SubRegs);
 }
 
-void RegScavenger::forward() {
-  // Move ptr forward.
-  if (!Tracking) {
-    MBBI = MBB->begin();
-    Tracking = true;
-  } else {
-    assert(MBBI != MBB->end() && "Already past the end of the basic block!");
-    MBBI = llvm::next(MBBI);
-  }
-  assert(MBBI != MBB->end() && "Already at the end of the basic block!");
+void RegScavenger::determineKillsAndDefs() {
+  assert(Tracking && "Must be tracking to determine kills and defs");
 
   MachineInstr *MI = MBBI;
-
-  if (MI == ScavengeRestore) {
-    ScavengedReg = 0;
-    ScavengeRestore = NULL;
-  }
-
-  if (MI->isDebugValue())
-    return;
+  assert(!MI->isDebugValue() && "Debug values have no kills or defs");
 
   // Find out which registers are early clobbered, killed, defined, and marked
   // def-dead in this instruction.
@@ -143,7 +130,7 @@ void RegScavenger::forward() {
     if (!MO.isReg())
       continue;
     unsigned Reg = MO.getReg();
-    if (!Reg || isReserved(Reg))
+    if (!Reg || TargetRegisterInfo::isVirtualRegister(Reg) || isReserved(Reg))
       continue;
 
     if (MO.isUse()) {
@@ -160,6 +147,53 @@ void RegScavenger::forward() {
         addRegWithSubRegs(DefRegs, Reg);
     }
   }
+}
+
+void RegScavenger::unprocess() {
+  assert(Tracking && "Cannot unprocess because we're not tracking");
+
+  MachineInstr *MI = MBBI;
+  if (!MI->isDebugValue()) {
+    determineKillsAndDefs();
+
+    // Commit the changes.
+    setUsed(KillRegs);
+    setUnused(DefRegs);
+  }
+
+  if (MBBI == MBB->begin()) {
+    MBBI = MachineBasicBlock::iterator(NULL);
+    Tracking = false;
+  } else
+    --MBBI;
+}
+
+void RegScavenger::forward() {
+  // Move ptr forward.
+  if (!Tracking) {
+    MBBI = MBB->begin();
+    Tracking = true;
+  } else {
+    assert(MBBI != MBB->end() && "Already past the end of the basic block!");
+    MBBI = llvm::next(MBBI);
+  }
+  assert(MBBI != MBB->end() && "Already at the end of the basic block!");
+
+  MachineInstr *MI = MBBI;
+
+  for (SmallVector<ScavengedInfo, 2>::iterator I = Scavenged.begin(),
+       IE = Scavenged.end(); I != IE; ++I) {
+    if (I->Restore != MI)
+      continue;
+
+    I->Reg = 0;
+    I->Restore = NULL;
+  }
+
+  if (MI->isDebugValue())
+    return;
+
+  determineKillsAndDefs();
 
   // Verify uses and defs.
 #ifndef NDEBUG
@@ -168,7 +202,7 @@ void RegScavenger::forward() {
     if (!MO.isReg())
       continue;
     unsigned Reg = MO.getReg();
-    if (!Reg || isReserved(Reg))
+    if (!Reg || TargetRegisterInfo::isVirtualRegister(Reg) || isReserved(Reg))
       continue;
     if (MO.isUse()) {
       if (MO.isUndef())
@@ -358,36 +392,47 @@ unsigned RegScavenger::scavengeRegister(const TargetRegisterClass *RC,
     return SReg;
   }
 
-  assert(ScavengedReg == 0 &&
-         "Scavenger slot is live, unable to scavenge another register!");
+  // Find an available scavenging slot.
+  unsigned SI;
+  for (SI = 0; SI < Scavenged.size(); ++SI)
+    if (Scavenged[SI].Reg == 0)
+      break;
+
+  if (SI == Scavenged.size()) {
+    // We need to scavenge a register but have no spill slot, the target
+    // must know how to do it (if not, we'll assert below).
+    Scavenged.push_back(ScavengedInfo());
+  }
 
   // Avoid infinite regress
-  ScavengedReg = SReg;
+  Scavenged[SI].Reg = SReg;
 
   // If the target knows how to save/restore the register, let it do so;
   // otherwise, use the emergency stack spill slot.
   if (!TRI->saveScavengerRegister(*MBB, I, UseMI, RC, SReg)) {
     // Spill the scavenged register before I.
-    assert(ScavengingFrameIndex >= 0 &&
+    assert(Scavenged[SI].FrameIndex >= 0 &&
            "Cannot scavenge register without an emergency spill slot!");
-    TII->storeRegToStackSlot(*MBB, I, SReg, true, ScavengingFrameIndex, RC,TRI);
+    TII->storeRegToStackSlot(*MBB, I, SReg, true, Scavenged[SI].FrameIndex,
+                             RC, TRI);
     MachineBasicBlock::iterator II = prior(I);
 
     unsigned FIOperandNum = getFrameIndexOperandNum(II);
     TRI->eliminateFrameIndex(II, SPAdj, FIOperandNum, this);
 
     // Restore the scavenged register before its use (or first terminator).
-    TII->loadRegFromStackSlot(*MBB, UseMI, SReg, ScavengingFrameIndex, RC, TRI);
+    TII->loadRegFromStackSlot(*MBB, UseMI, SReg, Scavenged[SI].FrameIndex,
+                              RC, TRI);
     II = prior(UseMI);
 
     FIOperandNum = getFrameIndexOperandNum(II);
     TRI->eliminateFrameIndex(II, SPAdj, FIOperandNum, this);
   }
 
-  ScavengeRestore = prior(UseMI);
+  Scavenged[SI].Restore = prior(UseMI);
 
   // Doing this here leads to infinite regress.
-  // ScavengedReg = SReg;
+  // Scavenged[SI].Reg = SReg;
 
   DEBUG(dbgs() << "Scavenged register (with spill): " << TRI->getName(SReg) <<
         "\n");