X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FTwoAddressInstructionPass.cpp;h=52a54eb5bd86876a418700207816dfb11edfa874;hb=253174bf50c932abaa680f465e2888c0e5272267;hp=0d715892136e10d1adc7434c9d9fac47d2c29ba5;hpb=32a3ac79116ce93471cd18ede24452c6af5b290b;p=oota-llvm.git diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp index 0d715892136..52a54eb5bd8 100644 --- a/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -37,7 +37,7 @@ #include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" -#include "llvm/Support/CommandLine.h" +#include "llvm/Target/TargetOptions.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/Debug.h" #include "llvm/ADT/BitVector.h" @@ -53,10 +53,6 @@ STATISTIC(NumConvertedTo3Addr, "Number of instructions promoted to 3-address"); STATISTIC(Num3AddrSunk, "Number of 3-address instructions sunk"); STATISTIC(NumReMats, "Number of instructions re-materialized"); -static cl::opt -EnableReMat("two-addr-remat", cl::init(false), cl::Hidden, - cl::desc("Two-addr conversion should remat when possible.")); - namespace { class VISIBILITY_HIDDEN TwoAddressInstructionPass : public MachineFunctionPass { @@ -69,21 +65,22 @@ namespace { unsigned Reg, MachineBasicBlock::iterator OldPos); - bool isSafeToReMat(unsigned DstReg, MachineInstr *MI); bool isProfitableToReMat(unsigned Reg, const TargetRegisterClass *RC, - MachineInstr *MI, unsigned Loc, - MachineInstr *DefMI, MachineBasicBlock *MBB, + MachineInstr *MI, MachineInstr *DefMI, + MachineBasicBlock *MBB, unsigned Loc, DenseMap &DistanceMap); public: static char ID; // Pass identification, replacement for typeid - TwoAddressInstructionPass() : MachineFunctionPass((intptr_t)&ID) {} + TwoAddressInstructionPass() : MachineFunctionPass(&ID) {} virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequired(); AU.addPreserved(); AU.addPreservedID(MachineLoopInfoID); AU.addPreservedID(MachineDominatorsID); - AU.addPreservedID(PHIEliminationID); + if (StrongPHIElim) + AU.addPreservedID(StrongPHIEliminationID); + else + AU.addPreservedID(PHIEliminationID); MachineFunctionPass::getAnalysisUsage(AU); } @@ -115,7 +112,7 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB, for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { const MachineOperand &MO = MI->getOperand(i); - if (!MO.isRegister()) + if (!MO.isReg()) continue; unsigned MOReg = MO.getReg(); if (!MOReg) @@ -165,7 +162,7 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB, ++NumVisited; for (unsigned i = 0, e = OtherMI->getNumOperands(); i != e; ++i) { MachineOperand &MO = OtherMI->getOperand(i); - if (!MO.isRegister()) + if (!MO.isReg()) continue; unsigned MOReg = MO.getReg(); if (!MOReg) @@ -189,9 +186,9 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB, KillMO->setIsKill(false); KillMO = MI->findRegisterUseOperand(SavedReg, false, TRI); KillMO->setIsKill(true); - LiveVariables::VarInfo& VarInfo = LV->getVarInfo(SavedReg); - VarInfo.removeKill(KillMI); - VarInfo.Kills.push_back(MI); + + if (LV) + LV->replaceKillInstruction(SavedReg, KillMI, MI); // Move instruction to its destination. MBB->remove(MI); @@ -201,40 +198,13 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB, return true; } -/// isSafeToReMat - Return true if it's safe to rematerialize the specified -/// instruction which defined the specified register instead of copying it. -bool -TwoAddressInstructionPass::isSafeToReMat(unsigned DstReg, MachineInstr *MI) { - const TargetInstrDesc &TID = MI->getDesc(); - if (!TID.isAsCheapAsAMove()) - return false; - bool SawStore = false; - if (!MI->isSafeToMove(TII, SawStore)) - return false; - for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { - MachineOperand &MO = MI->getOperand(i); - if (!MO.isRegister()) - continue; - // FIXME: For now, do not remat any instruction with register operands. - // Later on, we can loosen the restriction is the register operands have - // not been modified between the def and use. Note, this is different from - // MachineSink because the code in no longer in two-address form (at least - // partially). - if (MO.isUse()) - return false; - else if (!MO.isDead() && MO.getReg() != DstReg) - return false; - } - return true; -} - /// isTwoAddrUse - Return true if the specified MI is using the specified /// register as a two-address operand. static bool isTwoAddrUse(MachineInstr *UseMI, unsigned Reg) { const TargetInstrDesc &TID = UseMI->getDesc(); for (unsigned i = 0, e = TID.getNumOperands(); i != e; ++i) { MachineOperand &MO = UseMI->getOperand(i); - if (MO.isRegister() && MO.getReg() == Reg && + if (MO.isReg() && MO.getReg() == Reg && (MO.isDef() || TID.getOperandConstraint(i, TOI::TIED_TO) != -1)) // Earlier use is a two-address one. return true; @@ -248,12 +218,9 @@ static bool isTwoAddrUse(MachineInstr *UseMI, unsigned Reg) { bool TwoAddressInstructionPass::isProfitableToReMat(unsigned Reg, const TargetRegisterClass *RC, - MachineInstr *MI, unsigned Loc, - MachineInstr *DefMI, MachineBasicBlock *MBB, - DenseMap &DistanceMap) { - if (DefMI->getParent() != MBB) - return true; - // If earlier uses in MBB are not two-address uses, then don't remat. + MachineInstr *MI, MachineInstr *DefMI, + MachineBasicBlock *MBB, unsigned Loc, + DenseMap &DistanceMap){ bool OtherUse = false; for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg), UE = MRI->use_end(); UI != UE; ++UI) { @@ -261,18 +228,26 @@ TwoAddressInstructionPass::isProfitableToReMat(unsigned Reg, if (!UseMO.isUse()) continue; MachineInstr *UseMI = UseMO.getParent(); - if (UseMI->getParent() != MBB) - continue; - DenseMap::iterator DI = DistanceMap.find(UseMI); - if (DI != DistanceMap.end() && DI->second == Loc) - continue; // Current use. - OtherUse = true; - // There is at least one other use in the MBB that will clobber the - // register. - if (isTwoAddrUse(UseMI, Reg)) - return true; + MachineBasicBlock *UseMBB = UseMI->getParent(); + if (UseMBB == MBB) { + DenseMap::iterator DI = DistanceMap.find(UseMI); + if (DI != DistanceMap.end() && DI->second == Loc) + continue; // Current use. + OtherUse = true; + // There is at least one other use in the MBB that will clobber the + // register. + if (isTwoAddrUse(UseMI, Reg)) + return true; + } } - return !OtherUse; + + // If other uses in MBB are not two-address uses, then don't remat. + if (OtherUse) + return false; + + // No other uses in the same block, remat if it's defined in the same + // block so it does not unnecessarily extend the live range. + return MBB == DefMI->getParent(); } /// runOnMachineFunction - Reduce two-address instructions to two operands. @@ -283,7 +258,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { MRI = &MF.getRegInfo(); TII = TM.getInstrInfo(); TRI = TM.getRegisterInfo(); - LV = &getAnalysis(); + LV = getAnalysisToUpdate(); bool MadeChange = false; @@ -321,7 +296,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { FirstTied = false; - assert(mi->getOperand(si).isRegister() && mi->getOperand(si).getReg() && + assert(mi->getOperand(si).isReg() && mi->getOperand(si).getReg() && mi->getOperand(si).isUse() && "two address instruction invalid"); // If the two operands are the same we just remove the use @@ -345,7 +320,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { // should never occur because we are in SSA form. for (unsigned i = 0; i != mi->getNumOperands(); ++i) assert((int)i == ti || - !mi->getOperand(i).isRegister() || + !mi->getOperand(i).isReg() || mi->getOperand(i).getReg() != regA); #endif @@ -359,7 +334,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { // and C joinable. // FIXME: This code also works for A := B op C instructions. if (TID.isCommutable() && mi->getNumOperands() >= 3) { - assert(mi->getOperand(3-si).isRegister() && + assert(mi->getOperand(3-si).isReg() && "Not a proper commutative instruction!"); unsigned regC = mi->getOperand(3-si).getReg(); @@ -373,7 +348,10 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { DOUT << "2addr: COMMUTED TO: " << *NewMI; // If the instruction changed to commute it, update livevar. if (NewMI != mi) { - LV->instructionChanged(mi, NewMI); // Update live variables + if (LV) + // Update live variables + LV->replaceKillInstruction(regC, mi, NewMI); + mbbi->insert(mi, NewMI); // Insert the new inst mbbi->erase(mi); // Nuke the old inst. mi = NewMI; @@ -397,7 +375,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { assert(TID.getOperandConstraint(i, TOI::TIED_TO) == -1); #endif - MachineInstr *NewMI = TII->convertToThreeAddress(mbbi, mi, *LV); + MachineInstr *NewMI = TII->convertToThreeAddress(mbbi, mi, LV); if (NewMI) { DOUT << "2addr: CONVERTING 2-ADDR: " << *mi; DOUT << "2addr: TO 3-ADDR: " << *NewMI; @@ -428,9 +406,10 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { MachineInstr *DefMI = MRI->getVRegDef(regB); // If it's safe and profitable, remat the definition instead of // copying it. - if (EnableReMat && DefMI && - isSafeToReMat(regB, DefMI) && - isProfitableToReMat(regB, rc, mi, Dist, DefMI, mbbi,DistanceMap)){ + if (DefMI && + DefMI->getDesc().isAsCheapAsAMove() && + DefMI->isSafeToReMat(TII, regB) && + isProfitableToReMat(regB, rc, mi, DefMI, mbbi, Dist,DistanceMap)){ DEBUG(cerr << "2addr: REMATTING : " << *DefMI << "\n"); TII->reMaterialize(*mbbi, mi, regA, DefMI); ReMatRegs.set(regB); @@ -440,23 +419,26 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { } MachineBasicBlock::iterator prevMi = prior(mi); - DOUT << "\t\tprepend:\t"; DEBUG(prevMi->print(*cerr.stream(), &TM)); // Update live variables for regB. - LiveVariables::VarInfo& varInfoB = LV->getVarInfo(regB); + if (LV) { + LiveVariables::VarInfo& varInfoB = LV->getVarInfo(regB); - // regB is used in this BB. - varInfoB.UsedBlocks[mbbi->getNumber()] = true; + // regB is used in this BB. + varInfoB.UsedBlocks[mbbi->getNumber()] = true; - if (LV->removeVirtualRegisterKilled(regB, mbbi, mi)) - LV->addVirtualRegisterKilled(regB, prevMi); + if (LV->removeVirtualRegisterKilled(regB, mi)) + LV->addVirtualRegisterKilled(regB, prevMi); - if (LV->removeVirtualRegisterDead(regB, mbbi, mi)) - LV->addVirtualRegisterDead(regB, prevMi); + if (LV->removeVirtualRegisterDead(regB, mi)) + LV->addVirtualRegisterDead(regB, prevMi); + } + DOUT << "\t\tprepend:\t"; DEBUG(prevMi->print(*cerr.stream(), &TM)); + // Replace all occurences of regB with regA. for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) { - if (mi->getOperand(i).isRegister() && + if (mi->getOperand(i).isReg() && mi->getOperand(i).getReg() == regB) mi->getOperand(i).setReg(regA); } @@ -473,17 +455,14 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { } } - if (EnableReMat) { - // Some remat'ed instructions are dead. - int VReg = ReMatRegs.find_first(); - while (VReg != -1) { - if (MRI->use_empty(VReg)) { - MachineInstr *DefMI = MRI->getVRegDef(VReg); - DefMI->eraseFromParent(); - } - VReg = ReMatRegs.find_next(VReg); + // Some remat'ed instructions are dead. + int VReg = ReMatRegs.find_first(); + while (VReg != -1) { + if (MRI->use_empty(VReg)) { + MachineInstr *DefMI = MRI->getVRegDef(VReg); + DefMI->eraseFromParent(); } - + VReg = ReMatRegs.find_next(VReg); } return MadeChange;