diff options
Diffstat (limited to 'lib/CodeGen/TwoAddressInstructionPass.cpp')
| -rw-r--r-- | lib/CodeGen/TwoAddressInstructionPass.cpp | 119 |
1 files changed, 70 insertions, 49 deletions
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp index b3120b8be1ab..52ea87231ccd 100644 --- a/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -105,7 +105,7 @@ namespace { MachineFunction::iterator &mbbi, unsigned RegB, unsigned RegC, unsigned Dist); - bool isProfitableToConv3Addr(unsigned RegA); + bool isProfitableToConv3Addr(unsigned RegA, unsigned RegB); bool ConvertInstTo3Addr(MachineBasicBlock::iterator &mi, MachineBasicBlock::iterator &nmi, @@ -124,7 +124,11 @@ namespace { MachineBasicBlock::iterator &nmi, MachineFunction::iterator &mbbi, unsigned SrcIdx, unsigned DstIdx, - unsigned Dist); + unsigned Dist, + SmallPtrSet<MachineInstr*, 8> &Processed); + + void ScanUses(unsigned DstReg, MachineBasicBlock *MBB, + SmallPtrSet<MachineInstr*, 8> &Processed); void ProcessCopy(MachineInstr *MI, MachineBasicBlock *MBB, SmallPtrSet<MachineInstr*, 8> &Processed); @@ -615,16 +619,18 @@ TwoAddressInstructionPass::CommuteInstruction(MachineBasicBlock::iterator &mi, /// isProfitableToConv3Addr - Return true if it is profitable to convert the /// given 2-address instruction to a 3-address one. bool -TwoAddressInstructionPass::isProfitableToConv3Addr(unsigned RegA) { +TwoAddressInstructionPass::isProfitableToConv3Addr(unsigned RegA,unsigned RegB){ // Look for situations like this: // %reg1024<def> = MOV r1 // %reg1025<def> = MOV r0 // %reg1026<def> = ADD %reg1024, %reg1025 // r2 = MOV %reg1026 // Turn ADD into a 3-address instruction to avoid a copy. - unsigned FromRegA = getMappedReg(RegA, SrcRegMap); + unsigned FromRegB = getMappedReg(RegB, SrcRegMap); + if (!FromRegB) + return false; unsigned ToRegA = getMappedReg(RegA, DstRegMap); - return (FromRegA && ToRegA && !regsAreCompatible(FromRegA, ToRegA, TRI)); + return (ToRegA && !regsAreCompatible(FromRegB, ToRegA, TRI)); } /// ConvertInstTo3Addr - Convert the specified two-address instruction into a @@ -664,6 +670,54 @@ TwoAddressInstructionPass::ConvertInstTo3Addr(MachineBasicBlock::iterator &mi, return false; } +/// ScanUses - Scan forward recursively for only uses, update maps if the use +/// is a copy or a two-address instruction. +void +TwoAddressInstructionPass::ScanUses(unsigned DstReg, MachineBasicBlock *MBB, + SmallPtrSet<MachineInstr*, 8> &Processed) { + SmallVector<unsigned, 4> VirtRegPairs; + bool IsDstPhys; + bool IsCopy = false; + unsigned NewReg = 0; + unsigned Reg = DstReg; + while (MachineInstr *UseMI = findOnlyInterestingUse(Reg, MBB, MRI, TII,IsCopy, + NewReg, IsDstPhys)) { + if (IsCopy && !Processed.insert(UseMI)) + break; + + DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI); + if (DI != DistanceMap.end()) + // Earlier in the same MBB.Reached via a back edge. + break; + + if (IsDstPhys) { + VirtRegPairs.push_back(NewReg); + break; + } + bool isNew = SrcRegMap.insert(std::make_pair(NewReg, Reg)).second; + if (!isNew) + assert(SrcRegMap[NewReg] == Reg && "Can't map to two src registers!"); + VirtRegPairs.push_back(NewReg); + Reg = NewReg; + } + + if (!VirtRegPairs.empty()) { + unsigned ToReg = VirtRegPairs.back(); + VirtRegPairs.pop_back(); + while (!VirtRegPairs.empty()) { + unsigned FromReg = VirtRegPairs.back(); + VirtRegPairs.pop_back(); + bool isNew = DstRegMap.insert(std::make_pair(FromReg, ToReg)).second; + if (!isNew) + assert(DstRegMap[FromReg] == ToReg &&"Can't map to two dst registers!"); + ToReg = FromReg; + } + bool isNew = DstRegMap.insert(std::make_pair(DstReg, ToReg)).second; + if (!isNew) + assert(DstRegMap[DstReg] == ToReg && "Can't map to two dst registers!"); + } +} + /// ProcessCopy - If the specified instruction is not yet processed, process it /// if it's a copy. For a copy instruction, we find the physical registers the /// source and destination registers might be mapped to. These are kept in @@ -695,49 +749,11 @@ void TwoAddressInstructionPass::ProcessCopy(MachineInstr *MI, assert(SrcRegMap[DstReg] == SrcReg && "Can't map to two src physical registers!"); - SmallVector<unsigned, 4> VirtRegPairs; - bool IsCopy = false; - unsigned NewReg = 0; - while (MachineInstr *UseMI = findOnlyInterestingUse(DstReg, MBB, MRI,TII, - IsCopy, NewReg, IsDstPhys)) { - if (IsCopy) { - if (!Processed.insert(UseMI)) - break; - } - - DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI); - if (DI != DistanceMap.end()) - // Earlier in the same MBB.Reached via a back edge. - break; - - if (IsDstPhys) { - VirtRegPairs.push_back(NewReg); - break; - } - bool isNew = SrcRegMap.insert(std::make_pair(NewReg, DstReg)).second; - if (!isNew) - assert(SrcRegMap[NewReg] == DstReg && - "Can't map to two src physical registers!"); - VirtRegPairs.push_back(NewReg); - DstReg = NewReg; - } - - if (!VirtRegPairs.empty()) { - unsigned ToReg = VirtRegPairs.back(); - VirtRegPairs.pop_back(); - while (!VirtRegPairs.empty()) { - unsigned FromReg = VirtRegPairs.back(); - VirtRegPairs.pop_back(); - bool isNew = DstRegMap.insert(std::make_pair(FromReg, ToReg)).second; - if (!isNew) - assert(DstRegMap[FromReg] == ToReg && - "Can't map to two dst physical registers!"); - ToReg = FromReg; - } - } + ScanUses(DstReg, MBB, Processed); } Processed.insert(MI); + return; } /// isSafeToDelete - If the specified instruction does not produce any side @@ -836,7 +852,8 @@ bool TwoAddressInstructionPass:: TryInstructionTransform(MachineBasicBlock::iterator &mi, MachineBasicBlock::iterator &nmi, MachineFunction::iterator &mbbi, - unsigned SrcIdx, unsigned DstIdx, unsigned Dist) { + unsigned SrcIdx, unsigned DstIdx, unsigned Dist, + SmallPtrSet<MachineInstr*, 8> &Processed) { const TargetInstrDesc &TID = mi->getDesc(); unsigned regA = mi->getOperand(DstIdx).getReg(); unsigned regB = mi->getOperand(SrcIdx).getReg(); @@ -887,10 +904,13 @@ TryInstructionTransform(MachineBasicBlock::iterator &mi, return false; } + if (TargetRegisterInfo::isVirtualRegister(regA)) + ScanUses(regA, &*mbbi, Processed); + if (TID.isConvertibleTo3Addr()) { // This instruction is potentially convertible to a true // three-address instruction. Check if it is profitable. - if (!regBKilled || isProfitableToConv3Addr(regA)) { + if (!regBKilled || isProfitableToConv3Addr(regA, regB)) { // Try to convert it. if (ConvertInstTo3Addr(mi, nmi, mbbi, regA, regB, Dist)) { ++NumConvertedTo3Addr; @@ -951,7 +971,7 @@ TryInstructionTransform(MachineBasicBlock::iterator &mi, MachineBasicBlock::iterator NewMI = NewMIs[1]; bool TransformSuccess = TryInstructionTransform(NewMI, mi, mbbi, - NewSrcIdx, NewDstIdx, Dist); + NewSrcIdx, NewDstIdx, Dist, Processed); if (TransformSuccess || NewMIs[1]->getOperand(NewSrcIdx).isKill()) { // Success, or at least we made an improvement. Keep the unfolded @@ -1100,7 +1120,8 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { mi->getOperand(DstIdx).getReg()) break; // Done with this instruction. - if (TryInstructionTransform(mi, nmi, mbbi, SrcIdx, DstIdx, Dist)) + if (TryInstructionTransform(mi, nmi, mbbi, SrcIdx, DstIdx, Dist, + Processed)) break; // The tied operands have been eliminated. } |