[llvm] r279124 - RegScavenging: Add scavengeRegisterBackwards()

Quentin Colombet via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 18 13:22:40 PDT 2016


Hi Matthias,

Just to make sure, the test cases cover the off-by-1 fix, right?

Thanks,
-Quentin
> On Aug 18, 2016, at 12:47 PM, Matthias Braun via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Author: matze
> Date: Thu Aug 18 14:47:59 2016
> New Revision: 279124
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=279124&view=rev
> Log:
> RegScavenging: Add scavengeRegisterBackwards()
> 
> Re-apply r276044 with off-by-1 instruction fix for the reload placement.
> 
> This is a variant of scavengeRegister() that works for
> enterBasicBlockEnd()/backward(). The benefit of the backward mode is
> that it is not affected by incomplete kill flags.
> 
> This patch also changes
> PrologEpilogInserter::doScavengeFrameVirtualRegs() to use the register
> scavenger in backwards mode.
> 
> Differential Revision: http://reviews.llvm.org/D21885
> 
> Modified:
>    llvm/trunk/include/llvm/CodeGen/RegisterScavenging.h
>    llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
>    llvm/trunk/lib/CodeGen/RegisterScavenging.cpp
>    llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll
>    llvm/trunk/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll
>    llvm/trunk/test/CodeGen/PowerPC/dyn-alloca-aligned.ll
>    llvm/trunk/test/CodeGen/Thumb/large-stack.ll
> 
> Modified: llvm/trunk/include/llvm/CodeGen/RegisterScavenging.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/RegisterScavenging.h?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/CodeGen/RegisterScavenging.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/RegisterScavenging.h Thu Aug 18 14:47:59 2016
> @@ -157,12 +157,24 @@ public:
>   /// available and do the appropriate bookkeeping. SPAdj is the stack
>   /// adjustment due to call frame, it's passed along to eliminateFrameIndex().
>   /// Returns the scavenged register.
> +  /// This function performs worse if kill flags are incomplete, consider using
> +  /// scavengeRegisterBackwards() instead!
>   unsigned scavengeRegister(const TargetRegisterClass *RegClass,
>                             MachineBasicBlock::iterator I, int SPAdj);
>   unsigned scavengeRegister(const TargetRegisterClass *RegClass, int SPAdj) {
>     return scavengeRegister(RegClass, MBBI, SPAdj);
>   }
> 
> +  /// Make a register of the specific register class available from the current
> +  /// position backwards to the place before \p To. If \p RestoreAfter is true
> +  /// this includes the instruction following the current position.
> +  /// SPAdj is the stack adjustment due to call frame, it's passed along to
> +  /// eliminateFrameIndex().
> +  /// Returns the scavenged register.
> +  unsigned scavengeRegisterBackwards(const TargetRegisterClass &RC,
> +                                     MachineBasicBlock::iterator To,
> +                                     bool RestoreAfter, int SPAdj);
> +
>   /// Tell the scavenger a register is used.
>   void setRegUsed(unsigned Reg, LaneBitmask LaneMask = ~0u);
> private:
> @@ -202,6 +214,12 @@ private:
> 
>   /// Mark live-in registers of basic block as used.
>   void setLiveInsUsed(const MachineBasicBlock &MBB);
> +
> +  /// Spill a register after position \p After and reload it before position
> +  /// \p UseMI.
> +  ScavengedInfo &spill(unsigned Reg, const TargetRegisterClass &RC, int SPAdj,
> +                       MachineBasicBlock::iterator After,
> +                       MachineBasicBlock::iterator &UseMI);
> };
> 
> } // End llvm namespace
> 
> Modified: llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp (original)
> +++ llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp Thu Aug 18 14:47:59 2016
> @@ -41,6 +41,7 @@
> #include "llvm/Target/TargetMachine.h"
> #include "llvm/Target/TargetRegisterInfo.h"
> #include "llvm/Target/TargetSubtargetInfo.h"
> +#include <algorithm>
> #include <climits>
> 
> using namespace llvm;
> @@ -1145,6 +1146,55 @@ void PEI::replaceFrameIndices(MachineBas
>   }
> }
> 
> +/// Allocate a register for the virtual register \p VReg. The last use of
> +/// \p VReg is around the current position of the register scavenger \p RS.
> +/// \p ReserveAfter controls whether the scavenged register needs to be reserved
> +/// after the current instruction, otherwise it will only be reserved before the
> +/// current instruction.
> +static unsigned scavengeVReg(MachineRegisterInfo &MRI, RegScavenger &RS,
> +                             unsigned VReg, bool ReserveAfter) {
> +#ifndef NDEBUG
> +  // Verify that all definitions and uses are in the same basic block.
> +  const MachineBasicBlock *CommonMBB = nullptr;
> +  bool HadDef = false;
> +  for (MachineOperand &MO : MRI.reg_nodbg_operands(VReg)) {
> +    MachineBasicBlock *MBB = MO.getParent()->getParent();
> +    if (CommonMBB == nullptr)
> +      CommonMBB = MBB;
> +    assert(MBB == CommonMBB && "All defs+uses must be in the same basic block");
> +    if (MO.isDef())
> +      HadDef = true;
> +  }
> +  assert(HadDef && "Must have at least 1 Def");
> +#endif
> +
> +  // We should only have one definition of the register. However to accomodate
> +  // the requirements of two address code we also allow definitions in
> +  // subsequent instructions provided they also read the register. That way
> +  // we get a single contiguous lifetime.
> +  //
> +  // Definitions in MRI.def_begin() are unordered, search for the first.
> +  const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
> +  MachineRegisterInfo::def_iterator FirstDef =
> +    std::find_if(MRI.def_begin(VReg), MRI.def_end(),
> +                 [VReg, &TRI](const MachineOperand &MO) {
> +      return !MO.getParent()->readsRegister(VReg, &TRI);
> +    });
> +  assert(FirstDef != MRI.def_end() &&
> +         "Must have one definition that does not redefine vreg");
> +  MachineInstr &DefMI = *FirstDef->getParent();
> +
> +  // The register scavenger will report a free register inserting an emergency
> +  // spill/reload if necessary.
> +  int SPAdj = 0;
> +  const TargetRegisterClass &RC = *MRI.getRegClass(VReg);
> +  unsigned SReg = RS.scavengeRegisterBackwards(RC, DefMI.getIterator(),
> +                                               ReserveAfter, SPAdj);
> +  MRI.replaceRegWith(VReg, SReg);
> +  ++NumScavengedRegs;
> +  return SReg;
> +}
> +
> /// doScavengeFrameVirtualRegs - Replace all frame index virtual registers
> /// with physical registers. Use the register scavenger to find an
> /// appropriate register to use.
> @@ -1156,78 +1206,51 @@ static void
> doScavengeFrameVirtualRegs(MachineFunction &MF, RegScavenger *RS) {
>   // Run through the instructions and find any virtual registers.
>   MachineRegisterInfo &MRI = MF.getRegInfo();
> +  const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
>   for (MachineBasicBlock &MBB : MF) {
> -    RS->enterBasicBlock(MBB);
> +    RS->enterBasicBlockEnd(MBB);
> 
> -    int SPAdj = 0;
> -
> -    // The instruction stream may change in the loop, so check MBB.end()
> -    // directly.
> -    for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ) {
> -      // We might end up here again with a NULL iterator if we scavenged a
> -      // register for which we inserted spill code for definition by what was
> -      // originally the first instruction in MBB.
> -      if (I == MachineBasicBlock::iterator(nullptr))
> -        I = MBB.begin();
> +    bool LastIterationHadVRegUses = false;
> +    for (MachineBasicBlock::iterator I = MBB.end(); I != MBB.begin(); ) {
> +      --I;
> +      // Move RegScavenger to the position between *I and *std::next(I).
> +      RS->backward(I);
> +
> +      // Look for unassigned vregs in the uses of *std::next(I).
> +      if (LastIterationHadVRegUses) {
> +        MachineBasicBlock::iterator N = std::next(I);
> +        const MachineInstr &NMI = *N;
> +        for (const MachineOperand &MO : NMI.operands()) {
> +          if (!MO.isReg() || !MO.readsReg())
> +            continue;
> +          unsigned Reg = MO.getReg();
> +          if (TargetRegisterInfo::isVirtualRegister(Reg)) {
> +            unsigned SReg = scavengeVReg(MRI, *RS, Reg, true);
> +            N->addRegisterKilled(SReg, &TRI, false);
> +            RS->setRegUsed(SReg);
> +          }
> +        }
> +      }
> 
> +      // Look for unassigned vregs in the defs of *I.
> +      LastIterationHadVRegUses = false;
>       const MachineInstr &MI = *I;
> -      MachineBasicBlock::iterator J = std::next(I);
> -      MachineBasicBlock::iterator P =
> -                         I == MBB.begin() ? MachineBasicBlock::iterator(nullptr)
> -                                          : std::prev(I);
> -
> -      // RS should process this instruction before we might scavenge at this
> -      // location. This is because we might be replacing a virtual register
> -      // defined by this instruction, and if so, registers killed by this
> -      // instruction are available, and defined registers are not.
> -      RS->forward(I);
> -
>       for (const MachineOperand &MO : MI.operands()) {
>         if (!MO.isReg())
>           continue;
>         unsigned Reg = MO.getReg();
>         if (!TargetRegisterInfo::isVirtualRegister(Reg))
>           continue;
> -
> -        // When we first encounter a new virtual register, it
> -        // must be a definition.
> -        assert(MO.isDef() && "frame index virtual missing def!");
> -        // Scavenge a new scratch register
> -        const TargetRegisterClass *RC = MRI.getRegClass(Reg);
> -        unsigned ScratchReg = RS->scavengeRegister(RC, J, SPAdj);
> -
> -        ++NumScavengedRegs;
> -
> -        // Replace this reference to the virtual register with the
> -        // scratch register.
> -        assert(ScratchReg && "Missing scratch register!");
> -        MRI.replaceRegWith(Reg, ScratchReg);
> -
> -        // Because this instruction was processed by the RS before this
> -        // register was allocated, make sure that the RS now records the
> -        // register as being used.
> -        RS->setRegUsed(ScratchReg);
> +        // We have to look at all operands anyway so we can precalculate here
> +        // whether there is a reading operand. This allows use to skip the use
> +        // step in the next iteration if there was none.
> +        if (MO.readsReg())
> +          LastIterationHadVRegUses = true;
> +        if (MO.isDef()) {
> +          unsigned SReg = scavengeVReg(MRI, *RS, Reg, false);
> +          I->addRegisterDead(SReg, &TRI, false);
> +        }
>       }
> -
> -      // If the scavenger needed to use one of its spill slots, the
> -      // spill code will have been inserted in between I and J. This is a
> -      // problem because we need the spill code before I: Move I to just
> -      // prior to J.
> -      if (I != std::prev(J)) {
> -        MBB.splice(J, &MBB, I);
> -
> -        // Before we move I, we need to prepare the RS to visit I again.
> -        // Specifically, RS will assert if it sees uses of registers that
> -        // it believes are undefined. Because we have already processed
> -        // register kills in I, when it visits I again, it will believe that
> -        // those registers are undefined. To avoid this situation, unprocess
> -        // the instruction I.
> -        assert(RS->getCurrentPosition() == I &&
> -          "The register scavenger has an unexpected position");
> -        I = P;
> -        RS->unprocess(P);
> -      } else
> -        ++I;
>     }
>   }
> }
> 
> Modified: llvm/trunk/lib/CodeGen/RegisterScavenging.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterScavenging.cpp?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/RegisterScavenging.cpp (original)
> +++ llvm/trunk/lib/CodeGen/RegisterScavenging.cpp Thu Aug 18 14:47:59 2016
> @@ -299,6 +299,14 @@ void RegScavenger::backward() {
>     }
>   }
> 
> +  // Expire scavenge spill frameindex uses.
> +  for (ScavengedInfo &I : Scavenged) {
> +    if (I.Restore == &MI) {
> +      I.Reg = 0;
> +      I.Restore = nullptr;
> +    }
> +  }
> +
>   if (MBBI == MBB->begin()) {
>     MBBI = MachineBasicBlock::iterator(nullptr);
>     Tracking = false;
> @@ -398,6 +406,69 @@ unsigned RegScavenger::findSurvivorReg(M
>   return Survivor;
> }
> 
> +static std::pair<unsigned, MachineBasicBlock::iterator>
> +findSurvivorBackwards(const TargetRegisterInfo &TRI,
> +    MachineBasicBlock::iterator From, MachineBasicBlock::iterator To,
> +    BitVector &Available, BitVector &Candidates) {
> +  bool FoundTo = false;
> +  unsigned Survivor = 0;
> +  MachineBasicBlock::iterator Pos;
> +  MachineBasicBlock &MBB = *From->getParent();
> +  unsigned InstrLimit = 25;
> +  unsigned InstrCountDown = InstrLimit;
> +  for (MachineBasicBlock::iterator I = From;; --I) {
> +    const MachineInstr &MI = *I;
> +
> +    // Remove any candidates touched by instruction.
> +    bool FoundVReg = false;
> +    for (const MachineOperand &MO : MI.operands()) {
> +      if (MO.isRegMask()) {
> +        Candidates.clearBitsNotInMask(MO.getRegMask());
> +        continue;
> +      }
> +      if (!MO.isReg() || MO.isUndef() || MO.isDebug())
> +        continue;
> +      unsigned Reg = MO.getReg();
> +      if (TargetRegisterInfo::isVirtualRegister(Reg)) {
> +        FoundVReg = true;
> +      } else if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
> +        for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
> +          Candidates.reset(*AI);
> +      }
> +    }
> +
> +    if (I == To) {
> +      // If one of the available registers survived this long take it.
> +      Available &= Candidates;
> +      int Reg = Available.find_first();
> +      if (Reg != -1)
> +        return std::make_pair(Reg, MBB.end());
> +      // Otherwise we will continue up to InstrLimit instructions to find
> +      // the register which is not defined/used for the longest time.
> +      FoundTo = true;
> +      Pos = To;
> +    }
> +    if (FoundTo) {
> +      if (Survivor == 0 || !Candidates.test(Survivor)) {
> +        int Reg = Candidates.find_first();
> +        if (Reg == -1)
> +          break;
> +        Survivor = Reg;
> +      }
> +      if (--InstrCountDown == 0 || I == MBB.begin())
> +        break;
> +      if (FoundVReg) {
> +        // Keep searching when we find a vreg since the spilled register will
> +        // be usefull for this other vreg as well later.
> +        InstrCountDown = InstrLimit;
> +        Pos = I;
> +      }
> +    }
> +  }
> +
> +  return std::make_pair(Survivor, Pos);
> +}
> +
> static unsigned getFrameIndexOperandNum(MachineInstr &MI) {
>   unsigned i = 0;
>   while (!MI.getOperand(i).isFI()) {
> @@ -407,43 +478,16 @@ static unsigned getFrameIndexOperandNum(
>   return i;
> }
> 
> -unsigned RegScavenger::scavengeRegister(const TargetRegisterClass *RC,
> -                                        MachineBasicBlock::iterator I,
> -                                        int SPAdj) {
> -  MachineInstr &MI = *I;
> -  const MachineFunction &MF = *MI.getParent()->getParent();
> -  // Consider all allocatable registers in the register class initially
> -  BitVector Candidates = TRI->getAllocatableSet(MF, RC);
> -
> -  // Exclude all the registers being used by the instruction.
> -  for (const MachineOperand &MO : MI.operands()) {
> -    if (MO.isReg() && MO.getReg() != 0 && !(MO.isUse() && MO.isUndef()) &&
> -        !TargetRegisterInfo::isVirtualRegister(MO.getReg()))
> -      Candidates.reset(MO.getReg());
> -  }
> -
> -  // Try to find a register that's unused if there is one, as then we won't
> -  // have to spill.
> -  BitVector Available = getRegsAvailable(RC);
> -  Available &= Candidates;
> -  if (Available.any())
> -    Candidates = Available;
> -
> -  // Find the register whose use is furthest away.
> -  MachineBasicBlock::iterator UseMI;
> -  unsigned SReg = findSurvivorReg(I, Candidates, 25, UseMI);
> -
> -  // If we found an unused register there is no reason to spill it.
> -  if (!isRegUsed(SReg)) {
> -    DEBUG(dbgs() << "Scavenged register: " << TRI->getName(SReg) << "\n");
> -    return SReg;
> -  }
> -
> +RegScavenger::ScavengedInfo &
> +RegScavenger::spill(unsigned Reg, const TargetRegisterClass &RC, int SPAdj,
> +                    MachineBasicBlock::iterator Before,
> +                    MachineBasicBlock::iterator &UseMI) {
>   // Find an available scavenging slot with size and alignment matching
>   // the requirements of the class RC.
> +  const MachineFunction &MF = *Before->getParent()->getParent();
>   const MachineFrameInfo &MFI = MF.getFrameInfo();
> -  unsigned NeedSize = RC->getSize();
> -  unsigned NeedAlign = RC->getAlignment();
> +  unsigned NeedSize = RC.getSize();
> +  unsigned NeedAlign = RC.getAlignment();
> 
>   unsigned SI = Scavenged.size(), Diff = UINT_MAX;
>   int FIB = MFI.getObjectIndexBegin(), FIE = MFI.getObjectIndexEnd();
> @@ -478,42 +522,110 @@ unsigned RegScavenger::scavengeRegister(
>   }
> 
>   // Avoid infinite regress
> -  Scavenged[SI].Reg = SReg;
> +  Scavenged[SI].Reg = Reg;
> 
>   // 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.
> +  if (!TRI->saveScavengerRegister(*MBB, Before, UseMI, &RC, Reg)) {
> +    // Spill the scavenged register before \p Before.
>     int FI = Scavenged[SI].FrameIndex;
>     if (FI < FIB || FI >= FIE) {
>       std::string Msg = std::string("Error while trying to spill ") +
> -          TRI->getName(SReg) + " from class " + TRI->getRegClassName(RC) +
> +          TRI->getName(Reg) + " from class " + TRI->getRegClassName(&RC) +
>           ": Cannot scavenge register without an emergency spill slot!";
>       report_fatal_error(Msg.c_str());
>     }
> -    TII->storeRegToStackSlot(*MBB, I, SReg, true, Scavenged[SI].FrameIndex,
> -                             RC, TRI);
> -    MachineBasicBlock::iterator II = std::prev(I);
> +    TII->storeRegToStackSlot(*MBB, Before, Reg, true, Scavenged[SI].FrameIndex,
> +                             &RC, TRI);
> +    MachineBasicBlock::iterator II = std::prev(Before);
> 
>     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, Scavenged[SI].FrameIndex,
> -                              RC, TRI);
> +    TII->loadRegFromStackSlot(*MBB, UseMI, Reg, Scavenged[SI].FrameIndex,
> +                              &RC, TRI);
>     II = std::prev(UseMI);
> 
>     FIOperandNum = getFrameIndexOperandNum(*II);
>     TRI->eliminateFrameIndex(II, SPAdj, FIOperandNum, this);
>   }
> +  return Scavenged[SI];
> +}
> 
> -  Scavenged[SI].Restore = &*std::prev(UseMI);
> +unsigned RegScavenger::scavengeRegister(const TargetRegisterClass *RC,
> +                                        MachineBasicBlock::iterator I,
> +                                        int SPAdj) {
> +  MachineInstr &MI = *I;
> +  const MachineFunction &MF = *MI.getParent()->getParent();
> +  // Consider all allocatable registers in the register class initially
> +  BitVector Candidates = TRI->getAllocatableSet(MF, RC);
> 
> -  // Doing this here leads to infinite regress.
> -  // Scavenged[SI].Reg = SReg;
> +  // Exclude all the registers being used by the instruction.
> +  for (const MachineOperand &MO : MI.operands()) {
> +    if (MO.isReg() && MO.getReg() != 0 && !(MO.isUse() && MO.isUndef()) &&
> +        !TargetRegisterInfo::isVirtualRegister(MO.getReg()))
> +      Candidates.reset(MO.getReg());
> +  }
> +
> +  // Try to find a register that's unused if there is one, as then we won't
> +  // have to spill.
> +  BitVector Available = getRegsAvailable(RC);
> +  Available &= Candidates;
> +  if (Available.any())
> +    Candidates = Available;
> +
> +  // Find the register whose use is furthest away.
> +  MachineBasicBlock::iterator UseMI;
> +  unsigned SReg = findSurvivorReg(I, Candidates, 25, UseMI);
> +
> +  // If we found an unused register there is no reason to spill it.
> +  if (!isRegUsed(SReg)) {
> +    DEBUG(dbgs() << "Scavenged register: " << TRI->getName(SReg) << "\n");
> +    return SReg;
> +  }
> +
> +  ScavengedInfo &Scavenged = spill(SReg, *RC, SPAdj, I, UseMI);
> +  Scavenged.Restore = &*std::prev(UseMI);
> 
>   DEBUG(dbgs() << "Scavenged register (with spill): " << TRI->getName(SReg) <<
>         "\n");
> 
>   return SReg;
> }
> +
> +unsigned RegScavenger::scavengeRegisterBackwards(const TargetRegisterClass &RC,
> +                                                 MachineBasicBlock::iterator To,
> +                                                 bool RestoreAfter, int SPAdj) {
> +  const MachineBasicBlock &MBB = *To->getParent();
> +  const MachineFunction &MF = *MBB.getParent();
> +  // Consider all allocatable registers in the register class initially
> +  BitVector Candidates = TRI->getAllocatableSet(MF, &RC);
> +
> +  // Try to find a register that's unused if there is one, as then we won't
> +  // have to spill.
> +  BitVector Available = getRegsAvailable(&RC);
> +
> +  // Find the register whose use is furthest away.
> +  MachineBasicBlock::iterator UseMI;
> +  std::pair<unsigned, MachineBasicBlock::iterator> P =
> +      findSurvivorBackwards(*TRI, MBBI, To, Available, Candidates);
> +  unsigned Reg = P.first;
> +  assert(Reg != 0 && "No register left to scavenge!");
> +  // Found an available register?
> +  if (!Available.test(Reg)) {
> +    MachineBasicBlock::iterator ReloadAfter =
> +      RestoreAfter ? std::next(MBBI) : MBBI;
> +    MachineBasicBlock::iterator ReloadBefore = std::next(ReloadAfter);
> +    DEBUG(dbgs() << "Reload before: " << *ReloadBefore << '\n');
> +    MachineBasicBlock::iterator SpillBefore = P.second;
> +    ScavengedInfo &Scavenged = spill(Reg, RC, SPAdj, SpillBefore, ReloadBefore);
> +    Scavenged.Restore = &*std::prev(SpillBefore);
> +    addRegUnits(RegUnitsAvailable, Reg);
> +    DEBUG(dbgs() << "Scavenged register with spill: " << PrintReg(Reg, TRI)
> +          << " until " << *SpillBefore);
> +  } else {
> +    DEBUG(dbgs() << "Scavenged free register: " << PrintReg(Reg, TRI) << '\n');
> +  }
> +  return Reg;
> +}
> 
> Modified: llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll (original)
> +++ llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll Thu Aug 18 14:47:59 2016
> @@ -140,8 +140,8 @@ define void @stored_fi_to_global_2_small
> }
> 
> ; GCN-LABEL: {{^}}stored_fi_to_global_huge_frame_offset:
> -; GCN: s_add_i32 [[BASE_1_OFF_0:s[0-9]+]], 0, 0x3ffc
> -; GCN: v_mov_b32_e32 [[BASE_0:v[0-9]+]], 0{{$}}
> +; GCN-DAG: s_add_i32 [[BASE_1_OFF_0:s[0-9]+]], 0, 0x3ffc
> +; GCN-DAG: v_mov_b32_e32 [[BASE_0:v[0-9]+]], 0{{$}}
> ; GCN: buffer_store_dword [[BASE_0]], v{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, s{{[0-9]+}} offen
> 
> ; GCN: v_mov_b32_e32 [[V_BASE_1_OFF_0:v[0-9]+]], [[BASE_1_OFF_0]]
> 
> Modified: llvm/trunk/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll (original)
> +++ llvm/trunk/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll Thu Aug 18 14:47:59 2016
> @@ -1,34 +1,62 @@
> -; Check that register scavenging spill slot is close to $fp.
> ; RUN: llc -march=mipsel -O0 -relocation-model=pic < %s | FileCheck %s
> +; Check that register scavenging spill slot is close to $fp.
> +target triple="mipsel--"
> 
> -; CHECK: sw ${{.*}}, 8($sp)
> -; CHECK: lw ${{.*}}, 8($sp)
> + at var = external global i32
> + at ptrvar = external global i8*
> 
> -define i32 @main(i32 signext %argc, i8** %argv) #0 {
> -entry:
> -  %retval = alloca i32, align 4
> -  %argc.addr = alloca i32, align 4
> -  %argv.addr = alloca i8**, align 4
> -  %v0 = alloca <16 x i8>, align 16
> -  %.compoundliteral = alloca <16 x i8>, align 16
> -  %v1 = alloca <16 x i8>, align 16
> -  %.compoundliteral1 = alloca <16 x i8>, align 16
> -  %unused_variable = alloca [16384 x i32], align 4
> -  %result = alloca <16 x i8>, align 16
> -  store i32 0, i32* %retval
> -  store i32 %argc, i32* %argc.addr, align 4
> -  store i8** %argv, i8*** %argv.addr, align 4
> -  store <16 x i8> <i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 9, i8 10, i8 11, i8 12, i8 13, i8 14, i8 15, i8 16>, <16 x i8>* %.compoundliteral
> -  %0 = load <16 x i8>, <16 x i8>* %.compoundliteral
> -  store <16 x i8> %0, <16 x i8>* %v0, align 16
> -  store <16 x i8> zeroinitializer, <16 x i8>* %.compoundliteral1
> -  %1 = load <16 x i8>, <16 x i8>* %.compoundliteral1
> -  store <16 x i8> %1, <16 x i8>* %v1, align 16
> -  %2 = load <16 x i8>, <16 x i8>* %v0, align 16
> -  %3 = load <16 x i8>, <16 x i8>* %v1, align 16
> -  %mul = mul <16 x i8> %2, %3
> -  store <16 x i8> %mul, <16 x i8>* %result, align 16
> -  ret i32 0
> -}
> +; CHECK-LABEL: func:
> +define void @func() {
> +  %space = alloca i32, align 4
> +  %stackspace = alloca[16384 x i32], align 4
> +
> +  ; ensure stackspace is not optimized out
> +  %stackspace_casted = bitcast [16384 x i32]* %stackspace to i8*
> +  store volatile i8* %stackspace_casted, i8** @ptrvar
> 
> -attributes #0 = { noinline "no-frame-pointer-elim"="true" }
> +  ; Load values to increase register pressure.
> +  %v0 = load volatile i32, i32* @var
> +  %v1 = load volatile i32, i32* @var
> +  %v2 = load volatile i32, i32* @var
> +  %v3 = load volatile i32, i32* @var
> +  %v4 = load volatile i32, i32* @var
> +  %v5 = load volatile i32, i32* @var
> +  %v6 = load volatile i32, i32* @var
> +  %v7 = load volatile i32, i32* @var
> +  %v8 = load volatile i32, i32* @var
> +  %v9 = load volatile i32, i32* @var
> +  %v10 = load volatile i32, i32* @var
> +  %v11 = load volatile i32, i32* @var
> +  %v12 = load volatile i32, i32* @var
> +  %v13 = load volatile i32, i32* @var
> +  %v14 = load volatile i32, i32* @var
> +  %v15 = load volatile i32, i32* @var
> +  %v16 = load volatile i32, i32* @var
> +
> +  ; Computing a stack-relative values needs an additional register.
> +  ; We should get an emergency spill/reload for this.
> +  ; CHECK: sw ${{.*}}, 0($sp)
> +  ; CHECK: lw ${{.*}}, 0($sp)
> +  store volatile i32 %v0, i32* %space
> +
> +  ; store values so they are used.
> +  store volatile i32 %v0, i32* @var
> +  store volatile i32 %v1, i32* @var
> +  store volatile i32 %v2, i32* @var
> +  store volatile i32 %v3, i32* @var
> +  store volatile i32 %v4, i32* @var
> +  store volatile i32 %v5, i32* @var
> +  store volatile i32 %v6, i32* @var
> +  store volatile i32 %v7, i32* @var
> +  store volatile i32 %v8, i32* @var
> +  store volatile i32 %v9, i32* @var
> +  store volatile i32 %v10, i32* @var
> +  store volatile i32 %v11, i32* @var
> +  store volatile i32 %v12, i32* @var
> +  store volatile i32 %v13, i32* @var
> +  store volatile i32 %v14, i32* @var
> +  store volatile i32 %v15, i32* @var
> +  store volatile i32 %v16, i32* @var
> +
> +  ret void
> +}
> 
> Modified: llvm/trunk/test/CodeGen/PowerPC/dyn-alloca-aligned.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/dyn-alloca-aligned.ll?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/PowerPC/dyn-alloca-aligned.ll (original)
> +++ llvm/trunk/test/CodeGen/PowerPC/dyn-alloca-aligned.ll Thu Aug 18 14:47:59 2016
> @@ -25,8 +25,8 @@ entry:
> 
> ; CHECK-DAG: li [[REG1:[0-9]+]], -128
> ; CHECK-DAG: neg [[REG2:[0-9]+]],
> -; CHECK: and [[REG1]], [[REG2]], [[REG1]]
> -; CHECK: stdux {{[0-9]+}}, 1, [[REG1]]
> +; CHECK: and [[REG3:[0-9]+]], [[REG2]], [[REG1]]
> +; CHECK: stdux {{[0-9]+}}, 1, [[REG3]]
> 
> ; CHECK: blr
> 
> 
> Modified: llvm/trunk/test/CodeGen/Thumb/large-stack.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb/large-stack.ll?rev=279124&r1=279123&r2=279124&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/Thumb/large-stack.ll (original)
> +++ llvm/trunk/test/CodeGen/Thumb/large-stack.ll Thu Aug 18 14:47:59 2016
> @@ -46,8 +46,8 @@ define i32 @test3() {
> ; CHECK-LABEL: test3:
> ; CHECK: ldr [[TEMP:r[0-7]]],
> ; CHECK: add sp, [[TEMP]]
> -; CHECK: ldr [[TEMP]],
> -; CHECK: add [[TEMP]], sp
> +; CHECK: ldr [[TEMP2:r[0-7]]],
> +; CHECK: add [[TEMP2]], sp
> ; EABI: ldr [[TEMP:r[0-7]]],
> ; EABI: add sp, [[TEMP]]
> ; IOS: subs r4, r7, #4
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits



More information about the llvm-commits mailing list