X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegisterScavenging.cpp;h=5ec6564ce398c81862a8392ab62464c3bd9ee89d;hb=feab72c20acc97f8942148189c06e443b29df841;hp=7620cbbc42d307129dedefccbbb9bd309f5771fa;hpb=685c23e75842e64145fe319efd792abe72a827dd;p=oota-llvm.git

diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index 7620cbbc42d..5ec6564ce39 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -37,16 +37,13 @@ using namespace llvm;
 void RegScavenger::setUsed(unsigned Reg) {
   RegsAvailable.reset(Reg);
 
-  for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
-       unsigned SubReg = *SubRegs; ++SubRegs)
-    RegsAvailable.reset(SubReg);
+  for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+    RegsAvailable.reset(*SubRegs);
 }
 
 bool RegScavenger::isAliasUsed(unsigned Reg) const {
-  if (isUsed(Reg))
-    return true;
-  for (const unsigned *R = TRI->getAliasSet(Reg); *R; ++R)
-    if (isUsed(*R))
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+    if (isUsed(*AI))
       return true;
   return false;
 }
@@ -59,9 +56,6 @@ void RegScavenger::initRegState() {
   // All registers started out unused.
   RegsAvailable.set();
 
-  // Reserved registers are always used.
-  RegsAvailable ^= ReservedRegs;
-
   if (!MBB)
     return;
 
@@ -86,17 +80,21 @@ void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
   assert((NumPhysRegs == 0 || NumPhysRegs == TRI->getNumRegs()) &&
          "Target changed?");
 
+  // It is not possible to use the register scavenger after late optimization
+  // passes that don't preserve accurate liveness information.
+  assert(MRI->tracksLiveness() &&
+         "Cannot use register scavenger with inaccurate liveness");
+
   // Self-initialize.
   if (!MBB) {
     NumPhysRegs = TRI->getNumRegs();
     RegsAvailable.resize(NumPhysRegs);
-
-    // Create reserved registers bitvector.
-    ReservedRegs = TRI->getReservedRegs(MF);
+    KillRegs.resize(NumPhysRegs);
+    DefRegs.resize(NumPhysRegs);
 
     // Create callee-saved registers bitvector.
     CalleeSavedRegs.resize(NumPhysRegs);
-    const unsigned *CSRegs = TRI->getCalleeSavedRegs(&MF);
+    const uint16_t *CSRegs = TRI->getCalleeSavedRegs(&MF);
     if (CSRegs != NULL)
       for (unsigned i = 0; CSRegs[i]; ++i)
         CalleeSavedRegs.set(CSRegs[i]);
@@ -110,14 +108,8 @@ void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
 
 void RegScavenger::addRegWithSubRegs(BitVector &BV, unsigned Reg) {
   BV.set(Reg);
-  for (const unsigned *R = TRI->getSubRegisters(Reg); *R; R++)
-    BV.set(*R);
-}
-
-void RegScavenger::addRegWithAliases(BitVector &BV, unsigned Reg) {
-  BV.set(Reg);
-  for (const unsigned *R = TRI->getAliasSet(Reg); *R; R++)
-    BV.set(*R);
+  for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+    BV.set(*SubRegs);
 }
 
 void RegScavenger::forward() {
@@ -148,12 +140,12 @@ void RegScavenger::forward() {
   // predicated, conservatively assume "kill" markers do not actually kill the
   // register. Similarly ignores "dead" markers.
   bool isPred = TII->isPredicated(MI);
-  BitVector EarlyClobberRegs(NumPhysRegs);
-  BitVector KillRegs(NumPhysRegs);
-  BitVector DefRegs(NumPhysRegs);
-  BitVector DeadRegs(NumPhysRegs);
+  KillRegs.reset();
+  DefRegs.reset();
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI->getOperand(i);
+    if (MO.isRegMask())
+      (isPred ? DefRegs : KillRegs).setBitsNotInMask(MO.getRegMask());
     if (!MO.isReg())
       continue;
     unsigned Reg = MO.getReg();
@@ -164,21 +156,19 @@ void RegScavenger::forward() {
       // Ignore undef uses.
       if (MO.isUndef())
         continue;
-      // Two-address operands implicitly kill.
-      if (!isPred && (MO.isKill() || MI->isRegTiedToDefOperand(i)))
+      if (!isPred && MO.isKill())
         addRegWithSubRegs(KillRegs, Reg);
     } else {
       assert(MO.isDef());
       if (!isPred && MO.isDead())
-        addRegWithSubRegs(DeadRegs, Reg);
+        addRegWithSubRegs(KillRegs, Reg);
       else
         addRegWithSubRegs(DefRegs, Reg);
-      if (MO.isEarlyClobber())
-        addRegWithAliases(EarlyClobberRegs, Reg);
     }
   }
 
   // Verify uses and defs.
+#ifndef NDEBUG
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI->getOperand(i);
     if (!MO.isReg())
@@ -199,22 +189,17 @@ void RegScavenger::forward() {
         // Ideally we would like a way to model this, but leaving the
         // insert_subreg around causes both correctness and performance issues.
         bool SubUsed = false;
-        for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
-             unsigned SubReg = *SubRegs; ++SubRegs)
-          if (isUsed(SubReg)) {
+        for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+          if (isUsed(*SubRegs)) {
             SubUsed = true;
             break;
           }
-#ifndef NDEBUG
         if (!SubUsed) {
           MBB->getParent()->verify(NULL, "In Register Scavenger");
           llvm_unreachable("Using an undefined register!");
         }
-#endif
         (void)SubUsed;
       }
-      assert((!EarlyClobberRegs.test(Reg) || MI->isRegTiedToDefOperand(i)) &&
-             "Using an early clobbered register!");
     } else {
       assert(MO.isDef());
 #if 0
@@ -226,18 +211,20 @@ void RegScavenger::forward() {
 #endif
     }
   }
+#endif // NDEBUG
 
   // Commit the changes.
   setUnused(KillRegs);
-  setUnused(DeadRegs);
   setUsed(DefRegs);
 }
 
 void RegScavenger::getRegsUsed(BitVector &used, bool includeReserved) {
   used = RegsAvailable;
-  if (!includeReserved)
-    used |= ReservedRegs;
   used.flip();
+  if (includeReserved)
+    used |= MRI->getReservedRegs();
+  else
+    used.reset(MRI->getReservedRegs());
 }
 
 unsigned RegScavenger::FindUnusedReg(const TargetRegisterClass *RC) const {
@@ -291,6 +278,8 @@ unsigned RegScavenger::findSurvivorReg(MachineBasicBlock::iterator StartMI,
     // Remove any candidates touched by instruction.
     for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
       const MachineOperand &MO = MI->getOperand(i);
+      if (MO.isRegMask())
+        Candidates.clearBitsNotInMask(MO.getRegMask());
       if (!MO.isReg() || MO.isUndef() || !MO.getReg())
         continue;
       if (TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
@@ -300,9 +289,8 @@ unsigned RegScavenger::findSurvivorReg(MachineBasicBlock::iterator StartMI,
           isVirtKillInsn = true;
         continue;
       }
-      Candidates.reset(MO.getReg());
-      for (const unsigned *R = TRI->getAliasSet(MO.getReg()); *R; R++)
-        Candidates.reset(*R);
+      for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid(); ++AI)
+        Candidates.reset(*AI);
     }
     // If we're not in a virtual reg's live range, this is a valid
     // restore point.