Commit 5d0fbabe authored by Tanya Lattner's avatar Tanya Lattner
Browse files

Merge from mainline. 

Pre-alloc splitting needs to be more careful to avoid inserting spills/restores
between call frame setup/restore points.  Unfortunately, this regresses 
code size a bit, but at least it's correct now!

llvm-svn: 64508
parent 0a9fff57

llvm/lib/CodeGen/PreAllocSplitting.cpp

+72 −22
Original line number Diff line number Diff line
@@ -228,28 +228,52 @@ PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI, 
      ++MII;

      unsigned Index = LIs->getInstructionIndex(MII);

      unsigned Gap = LIs->findGapBeforeInstr(Index);

      if (Gap) {

        Pt = MII;

        SpillIndex = Gap;

        break;

      

      // We can't insert the spill between the barrier (a call), and its

      // corresponding call frame setup.

      } else if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode() &&

                 MII == MachineBasicBlock::iterator(MI))

      // corresponding call frame setup/teardown.

      if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {

        bool reachedBarrier = false;

        do {

          if (MII == EndPt) {

            reachedBarrier = true;

            break;

          }

          ++MII;

        } while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode());

        

        if (reachedBarrier) break;

      } else if (Gap) {

        Pt = MII;

        SpillIndex = Gap;

        break;

      }

    } while (MII != EndPt);

  } else {

    MachineBasicBlock::iterator MII = MI;

    MachineBasicBlock::iterator EndPt = DefMI

      ? MachineBasicBlock::iterator(DefMI) : MBB->begin();

    

    // We can't insert the spill between the barrier (a call), and its

    // corresponding call frame setup.

    if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) --MII;

    while (MII != EndPt && !RefsInMBB.count(MII)) {

      unsigned Index = LIs->getInstructionIndex(MII);

      if (LIs->hasGapBeforeInstr(Index)) {

      

      // We can't insert the spill between the barrier (a call), and its

      // corresponding call frame setup.

      if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {

        --MII;

        continue;

      } if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {

        bool reachedBarrier = false;

        while (MII->getOpcode() != TRI->getCallFrameSetupOpcode()) {

          --MII;

          if (MII == EndPt) {

            reachedBarrier = true;

            break;

          }

        }

        

        if (reachedBarrier) break;

        else continue;

      } else if (LIs->hasGapBeforeInstr(Index)) {

        Pt = MII;

        SpillIndex = LIs->findGapBeforeInstr(Index, true);

      }
@@ -283,25 +307,32 @@ PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI, 
    do {

      unsigned Index = LIs->getInstructionIndex(MII);

      unsigned Gap = LIs->findGapBeforeInstr(Index);

      if (Gap) {

        Pt = MII;

        RestoreIndex = Gap;

        break;

      

      // We can't insert a restore between the barrier (a call) and its 

      // corresponding call frame teardown.

      } else if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode() &&

                 prior(MII) == MachineBasicBlock::iterator(MI))

      if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {

        bool reachedBarrier = false;

        while (MII->getOpcode() != TRI->getCallFrameSetupOpcode()) {

          --MII;

          if (MII == EndPt) {

            reachedBarrier = true;

            break;

          }

        }

        

        if (reachedBarrier) break;

        else continue;

      } else if (Gap) {

        Pt = MII;

        RestoreIndex = Gap;

        break;

      }

      

      --MII;

    } while (MII != EndPt);

  } else {

    MachineBasicBlock::iterator MII = MI;

    MII = ++MII;

    // We can't insert a restore between the barrier (a call) and its 

    // corresponding call frame teardown.

    if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode())

      ++MII;

    

    // FIXME: Limit the number of instructions to examine to reduce

    // compile time?
@@ -310,10 +341,29 @@ PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI, 
      if (Index > LastIdx)

        break;

      unsigned Gap = LIs->findGapBeforeInstr(Index);

      if (Gap) {

      

      // We can't insert a restore between the barrier (a call) and its 

      // corresponding call frame teardown.

      if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {

        ++MII;

        continue;

      } else if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {

        bool reachedBarrier = false;

        do {

          if (MII == MBB->getFirstTerminator() || RefsInMBB.count(MII)) {

            reachedBarrier = true;

            break;

          }

          

          ++MII;

        } while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode());

        

        if (reachedBarrier) break;

      } else if (Gap) {

        Pt = MII;

        RestoreIndex = Gap;

      }

      

      if (RefsInMBB.count(MII))

        break;

      ++MII;