//===-- PPCInstrInfo.cpp - PowerPC Instruction Information ----------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains the PowerPC implementation of the TargetInstrInfo class. // //===----------------------------------------------------------------------===// #include "PPCInstrInfo.h" #include "MCTargetDesc/PPCPredicates.h" #include "PPC.h" #include "PPCHazardRecognizers.h" #include "PPCInstrBuilder.h" #include "PPCMachineFunctionInfo.h" #include "PPCTargetMachine.h" #include "llvm/ADT/Statistic.h" #include "llvm/ADT/STLExtras.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineMemOperand.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/PseudoSourceValue.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/TargetRegistry.h" #include "llvm/Support/raw_ostream.h" #define GET_INSTRMAP_INFO #define GET_INSTRINFO_CTOR_DTOR #include "PPCGenInstrInfo.inc" using namespace llvm; static cl:: opt DisableCTRLoopAnal("disable-ppc-ctrloop-analysis", cl::Hidden, cl::desc("Disable analysis for CTR loops")); static cl::opt DisableCmpOpt("disable-ppc-cmp-opt", cl::desc("Disable compare instruction optimization"), cl::Hidden); // Pin the vtable to this file. void PPCInstrInfo::anchor() {} PPCInstrInfo::PPCInstrInfo(PPCTargetMachine &tm) : PPCGenInstrInfo(PPC::ADJCALLSTACKDOWN, PPC::ADJCALLSTACKUP), TM(tm), RI(*TM.getSubtargetImpl()) {} /// CreateTargetHazardRecognizer - Return the hazard recognizer to use for /// this target when scheduling the DAG. ScheduleHazardRecognizer *PPCInstrInfo::CreateTargetHazardRecognizer( const TargetMachine *TM, const ScheduleDAG *DAG) const { unsigned Directive = TM->getSubtarget().getDarwinDirective(); if (Directive == PPC::DIR_440 || Directive == PPC::DIR_A2 || Directive == PPC::DIR_E500mc || Directive == PPC::DIR_E5500) { const InstrItineraryData *II = TM->getInstrItineraryData(); return new PPCScoreboardHazardRecognizer(II, DAG); } return TargetInstrInfo::CreateTargetHazardRecognizer(TM, DAG); } /// CreateTargetPostRAHazardRecognizer - Return the postRA hazard recognizer /// to use for this target when scheduling the DAG. ScheduleHazardRecognizer *PPCInstrInfo::CreateTargetPostRAHazardRecognizer( const InstrItineraryData *II, const ScheduleDAG *DAG) const { unsigned Directive = TM.getSubtarget().getDarwinDirective(); // Most subtargets use a PPC970 recognizer. if (Directive != PPC::DIR_440 && Directive != PPC::DIR_A2 && Directive != PPC::DIR_E500mc && Directive != PPC::DIR_E5500) { assert(TM.getInstrInfo() && "No InstrInfo?"); return new PPCHazardRecognizer970(TM); } return new PPCScoreboardHazardRecognizer(II, DAG); } // Detect 32 -> 64-bit extensions where we may reuse the low sub-register. bool PPCInstrInfo::isCoalescableExtInstr(const MachineInstr &MI, unsigned &SrcReg, unsigned &DstReg, unsigned &SubIdx) const { switch (MI.getOpcode()) { default: return false; case PPC::EXTSW: case PPC::EXTSW_32_64: SrcReg = MI.getOperand(1).getReg(); DstReg = MI.getOperand(0).getReg(); SubIdx = PPC::sub_32; return true; } } unsigned PPCInstrInfo::isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const { // Note: This list must be kept consistent with LoadRegFromStackSlot. switch (MI->getOpcode()) { default: break; case PPC::LD: case PPC::LWZ: case PPC::LFS: case PPC::LFD: case PPC::RESTORE_CR: case PPC::LVX: case PPC::RESTORE_VRSAVE: // Check for the operands added by addFrameReference (the immediate is the // offset which defaults to 0). if (MI->getOperand(1).isImm() && !MI->getOperand(1).getImm() && MI->getOperand(2).isFI()) { FrameIndex = MI->getOperand(2).getIndex(); return MI->getOperand(0).getReg(); } break; } return 0; } unsigned PPCInstrInfo::isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const { // Note: This list must be kept consistent with StoreRegToStackSlot. switch (MI->getOpcode()) { default: break; case PPC::STD: case PPC::STW: case PPC::STFS: case PPC::STFD: case PPC::SPILL_CR: case PPC::STVX: case PPC::SPILL_VRSAVE: // Check for the operands added by addFrameReference (the immediate is the // offset which defaults to 0). if (MI->getOperand(1).isImm() && !MI->getOperand(1).getImm() && MI->getOperand(2).isFI()) { FrameIndex = MI->getOperand(2).getIndex(); return MI->getOperand(0).getReg(); } break; } return 0; } // commuteInstruction - We can commute rlwimi instructions, but only if the // rotate amt is zero. We also have to munge the immediates a bit. MachineInstr * PPCInstrInfo::commuteInstruction(MachineInstr *MI, bool NewMI) const { MachineFunction &MF = *MI->getParent()->getParent(); // Normal instructions can be commuted the obvious way. if (MI->getOpcode() != PPC::RLWIMI && MI->getOpcode() != PPC::RLWIMIo) return TargetInstrInfo::commuteInstruction(MI, NewMI); // Cannot commute if it has a non-zero rotate count. if (MI->getOperand(3).getImm() != 0) return 0; // If we have a zero rotate count, we have: // M = mask(MB,ME) // Op0 = (Op1 & ~M) | (Op2 & M) // Change this to: // M = mask((ME+1)&31, (MB-1)&31) // Op0 = (Op2 & ~M) | (Op1 & M) // Swap op1/op2 unsigned Reg0 = MI->getOperand(0).getReg(); unsigned Reg1 = MI->getOperand(1).getReg(); unsigned Reg2 = MI->getOperand(2).getReg(); bool Reg1IsKill = MI->getOperand(1).isKill(); bool Reg2IsKill = MI->getOperand(2).isKill(); bool ChangeReg0 = false; // If machine instrs are no longer in two-address forms, update // destination register as well. if (Reg0 == Reg1) { // Must be two address instruction! assert(MI->getDesc().getOperandConstraint(0, MCOI::TIED_TO) && "Expecting a two-address instruction!"); Reg2IsKill = false; ChangeReg0 = true; } // Masks. unsigned MB = MI->getOperand(4).getImm(); unsigned ME = MI->getOperand(5).getImm(); if (NewMI) { // Create a new instruction. unsigned Reg0 = ChangeReg0 ? Reg2 : MI->getOperand(0).getReg(); bool Reg0IsDead = MI->getOperand(0).isDead(); return BuildMI(MF, MI->getDebugLoc(), MI->getDesc()) .addReg(Reg0, RegState::Define | getDeadRegState(Reg0IsDead)) .addReg(Reg2, getKillRegState(Reg2IsKill)) .addReg(Reg1, getKillRegState(Reg1IsKill)) .addImm((ME+1) & 31) .addImm((MB-1) & 31); } if (ChangeReg0) MI->getOperand(0).setReg(Reg2); MI->getOperand(2).setReg(Reg1); MI->getOperand(1).setReg(Reg2); MI->getOperand(2).setIsKill(Reg1IsKill); MI->getOperand(1).setIsKill(Reg2IsKill); // Swap the mask around. MI->getOperand(4).setImm((ME+1) & 31); MI->getOperand(5).setImm((MB-1) & 31); return MI; } void PPCInstrInfo::insertNoop(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const { DebugLoc DL; BuildMI(MBB, MI, DL, get(PPC::NOP)); } // Branch analysis. // Note: If the condition register is set to CTR or CTR8 then this is a // BDNZ (imm == 1) or BDZ (imm == 0) branch. bool PPCInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB, MachineBasicBlock *&FBB, SmallVectorImpl &Cond, bool AllowModify) const { bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); // If the block has no terminators, it just falls into the block after it. MachineBasicBlock::iterator I = MBB.end(); if (I == MBB.begin()) return false; --I; while (I->isDebugValue()) { if (I == MBB.begin()) return false; --I; } if (!isUnpredicatedTerminator(I)) return false; // Get the last instruction in the block. MachineInstr *LastInst = I; // If there is only one terminator instruction, process it. if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) { if (LastInst->getOpcode() == PPC::B) { if (!LastInst->getOperand(0).isMBB()) return true; TBB = LastInst->getOperand(0).getMBB(); return false; } else if (LastInst->getOpcode() == PPC::BCC) { if (!LastInst->getOperand(2).isMBB()) return true; // Block ends with fall-through condbranch. TBB = LastInst->getOperand(2).getMBB(); Cond.push_back(LastInst->getOperand(0)); Cond.push_back(LastInst->getOperand(1)); return false; } else if (LastInst->getOpcode() == PPC::BDNZ8 || LastInst->getOpcode() == PPC::BDNZ) { if (!LastInst->getOperand(0).isMBB()) return true; if (DisableCTRLoopAnal) return true; TBB = LastInst->getOperand(0).getMBB(); Cond.push_back(MachineOperand::CreateImm(1)); Cond.push_back(MachineOperand::CreateReg(isPPC64 ? PPC::CTR8 : PPC::CTR, true)); return false; } else if (LastInst->getOpcode() == PPC::BDZ8 || LastInst->getOpcode() == PPC::BDZ) { if (!LastInst->getOperand(0).isMBB()) return true; if (DisableCTRLoopAnal) return true; TBB = LastInst->getOperand(0).getMBB(); Cond.push_back(MachineOperand::CreateImm(0)); Cond.push_back(MachineOperand::CreateReg(isPPC64 ? PPC::CTR8 : PPC::CTR, true)); return false; } // Otherwise, don't know what this is. return true; } // Get the instruction before it if it's a terminator. MachineInstr *SecondLastInst = I; // If there are three terminators, we don't know what sort of block this is. if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I)) return true; // If the block ends with PPC::B and PPC:BCC, handle it. if (SecondLastInst->getOpcode() == PPC::BCC && LastInst->getOpcode() == PPC::B) { if (!SecondLastInst->getOperand(2).isMBB() || !LastInst->getOperand(0).isMBB()) return true; TBB = SecondLastInst->getOperand(2).getMBB(); Cond.push_back(SecondLastInst->getOperand(0)); Cond.push_back(SecondLastInst->getOperand(1)); FBB = LastInst->getOperand(0).getMBB(); return false; } else if ((SecondLastInst->getOpcode() == PPC::BDNZ8 || SecondLastInst->getOpcode() == PPC::BDNZ) && LastInst->getOpcode() == PPC::B) { if (!SecondLastInst->getOperand(0).isMBB() || !LastInst->getOperand(0).isMBB()) return true; if (DisableCTRLoopAnal) return true; TBB = SecondLastInst->getOperand(0).getMBB(); Cond.push_back(MachineOperand::CreateImm(1)); Cond.push_back(MachineOperand::CreateReg(isPPC64 ? PPC::CTR8 : PPC::CTR, true)); FBB = LastInst->getOperand(0).getMBB(); return false; } else if ((SecondLastInst->getOpcode() == PPC::BDZ8 || SecondLastInst->getOpcode() == PPC::BDZ) && LastInst->getOpcode() == PPC::B) { if (!SecondLastInst->getOperand(0).isMBB() || !LastInst->getOperand(0).isMBB()) return true; if (DisableCTRLoopAnal) return true; TBB = SecondLastInst->getOperand(0).getMBB(); Cond.push_back(MachineOperand::CreateImm(0)); Cond.push_back(MachineOperand::CreateReg(isPPC64 ? PPC::CTR8 : PPC::CTR, true)); FBB = LastInst->getOperand(0).getMBB(); return false; } // If the block ends with two PPC:Bs, handle it. The second one is not // executed, so remove it. if (SecondLastInst->getOpcode() == PPC::B && LastInst->getOpcode() == PPC::B) { if (!SecondLastInst->getOperand(0).isMBB()) return true; TBB = SecondLastInst->getOperand(0).getMBB(); I = LastInst; if (AllowModify) I->eraseFromParent(); return false; } // Otherwise, can't handle this. return true; } unsigned PPCInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const { MachineBasicBlock::iterator I = MBB.end(); if (I == MBB.begin()) return 0; --I; while (I->isDebugValue()) { if (I == MBB.begin()) return 0; --I; } if (I->getOpcode() != PPC::B && I->getOpcode() != PPC::BCC && I->getOpcode() != PPC::BDNZ8 && I->getOpcode() != PPC::BDNZ && I->getOpcode() != PPC::BDZ8 && I->getOpcode() != PPC::BDZ) return 0; // Remove the branch. I->eraseFromParent(); I = MBB.end(); if (I == MBB.begin()) return 1; --I; if (I->getOpcode() != PPC::BCC && I->getOpcode() != PPC::BDNZ8 && I->getOpcode() != PPC::BDNZ && I->getOpcode() != PPC::BDZ8 && I->getOpcode() != PPC::BDZ) return 1; // Remove the branch. I->eraseFromParent(); return 2; } unsigned PPCInstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB, const SmallVectorImpl &Cond, DebugLoc DL) const { // Shouldn't be a fall through. assert(TBB && "InsertBranch must not be told to insert a fallthrough"); assert((Cond.size() == 2 || Cond.size() == 0) && "PPC branch conditions have two components!"); bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); // One-way branch. if (FBB == 0) { if (Cond.empty()) // Unconditional branch BuildMI(&MBB, DL, get(PPC::B)).addMBB(TBB); else if (Cond[1].getReg() == PPC::CTR || Cond[1].getReg() == PPC::CTR8) BuildMI(&MBB, DL, get(Cond[0].getImm() ? (isPPC64 ? PPC::BDNZ8 : PPC::BDNZ) : (isPPC64 ? PPC::BDZ8 : PPC::BDZ))).addMBB(TBB); else // Conditional branch BuildMI(&MBB, DL, get(PPC::BCC)) .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB); return 1; } // Two-way Conditional Branch. if (Cond[1].getReg() == PPC::CTR || Cond[1].getReg() == PPC::CTR8) BuildMI(&MBB, DL, get(Cond[0].getImm() ? (isPPC64 ? PPC::BDNZ8 : PPC::BDNZ) : (isPPC64 ? PPC::BDZ8 : PPC::BDZ))).addMBB(TBB); else BuildMI(&MBB, DL, get(PPC::BCC)) .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB); BuildMI(&MBB, DL, get(PPC::B)).addMBB(FBB); return 2; } // Select analysis. bool PPCInstrInfo::canInsertSelect(const MachineBasicBlock &MBB, const SmallVectorImpl &Cond, unsigned TrueReg, unsigned FalseReg, int &CondCycles, int &TrueCycles, int &FalseCycles) const { if (!TM.getSubtargetImpl()->hasISEL()) return false; if (Cond.size() != 2) return false; // If this is really a bdnz-like condition, then it cannot be turned into a // select. if (Cond[1].getReg() == PPC::CTR || Cond[1].getReg() == PPC::CTR8) return false; // Check register classes. const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo(); const TargetRegisterClass *RC = RI.getCommonSubClass(MRI.getRegClass(TrueReg), MRI.getRegClass(FalseReg)); if (!RC) return false; // isel is for regular integer GPRs only. if (!PPC::GPRCRegClass.hasSubClassEq(RC) && !PPC::GPRC_NOR0RegClass.hasSubClassEq(RC) && !PPC::G8RCRegClass.hasSubClassEq(RC) && !PPC::G8RC_NOX0RegClass.hasSubClassEq(RC)) return false; // FIXME: These numbers are for the A2, how well they work for other cores is // an open question. On the A2, the isel instruction has a 2-cycle latency // but single-cycle throughput. These numbers are used in combination with // the MispredictPenalty setting from the active SchedMachineModel. CondCycles = 1; TrueCycles = 1; FalseCycles = 1; return true; } void PPCInstrInfo::insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, DebugLoc dl, unsigned DestReg, const SmallVectorImpl &Cond, unsigned TrueReg, unsigned FalseReg) const { assert(Cond.size() == 2 && "PPC branch conditions have two components!"); assert(TM.getSubtargetImpl()->hasISEL() && "Cannot insert select on target without ISEL support"); // Get the register classes. MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo(); const TargetRegisterClass *RC = RI.getCommonSubClass(MRI.getRegClass(TrueReg), MRI.getRegClass(FalseReg)); assert(RC && "TrueReg and FalseReg must have overlapping register classes"); bool Is64Bit = PPC::G8RCRegClass.hasSubClassEq(RC) || PPC::G8RC_NOX0RegClass.hasSubClassEq(RC); assert((Is64Bit || PPC::GPRCRegClass.hasSubClassEq(RC) || PPC::GPRC_NOR0RegClass.hasSubClassEq(RC)) && "isel is for regular integer GPRs only"); unsigned OpCode = Is64Bit ? PPC::ISEL8 : PPC::ISEL; unsigned SelectPred = Cond[0].getImm(); unsigned SubIdx; bool SwapOps; switch (SelectPred) { default: llvm_unreachable("invalid predicate for isel"); case PPC::PRED_EQ: SubIdx = PPC::sub_eq; SwapOps = false; break; case PPC::PRED_NE: SubIdx = PPC::sub_eq; SwapOps = true; break; case PPC::PRED_LT: SubIdx = PPC::sub_lt; SwapOps = false; break; case PPC::PRED_GE: SubIdx = PPC::sub_lt; SwapOps = true; break; case PPC::PRED_GT: SubIdx = PPC::sub_gt; SwapOps = false; break; case PPC::PRED_LE: SubIdx = PPC::sub_gt; SwapOps = true; break; case PPC::PRED_UN: SubIdx = PPC::sub_un; SwapOps = false; break; case PPC::PRED_NU: SubIdx = PPC::sub_un; SwapOps = true; break; } unsigned FirstReg = SwapOps ? FalseReg : TrueReg, SecondReg = SwapOps ? TrueReg : FalseReg; // The first input register of isel cannot be r0. If it is a member // of a register class that can be r0, then copy it first (the // register allocator should eliminate the copy). if (MRI.getRegClass(FirstReg)->contains(PPC::R0) || MRI.getRegClass(FirstReg)->contains(PPC::X0)) { const TargetRegisterClass *FirstRC = MRI.getRegClass(FirstReg)->contains(PPC::X0) ? &PPC::G8RC_NOX0RegClass : &PPC::GPRC_NOR0RegClass; unsigned OldFirstReg = FirstReg; FirstReg = MRI.createVirtualRegister(FirstRC); BuildMI(MBB, MI, dl, get(TargetOpcode::COPY), FirstReg) .addReg(OldFirstReg); } BuildMI(MBB, MI, dl, get(OpCode), DestReg) .addReg(FirstReg).addReg(SecondReg) .addReg(Cond[1].getReg(), 0, SubIdx); } void PPCInstrInfo::copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I, DebugLoc DL, unsigned DestReg, unsigned SrcReg, bool KillSrc) const { unsigned Opc; if (PPC::GPRCRegClass.contains(DestReg, SrcReg)) Opc = PPC::OR; else if (PPC::G8RCRegClass.contains(DestReg, SrcReg)) Opc = PPC::OR8; else if (PPC::F4RCRegClass.contains(DestReg, SrcReg)) Opc = PPC::FMR; else if (PPC::CRRCRegClass.contains(DestReg, SrcReg)) Opc = PPC::MCRF; else if (PPC::VRRCRegClass.contains(DestReg, SrcReg)) Opc = PPC::VOR; else if (PPC::CRBITRCRegClass.contains(DestReg, SrcReg)) Opc = PPC::CROR; else llvm_unreachable("Impossible reg-to-reg copy"); const MCInstrDesc &MCID = get(Opc); if (MCID.getNumOperands() == 3) BuildMI(MBB, I, DL, MCID, DestReg) .addReg(SrcReg).addReg(SrcReg, getKillRegState(KillSrc)); else BuildMI(MBB, I, DL, MCID, DestReg).addReg(SrcReg, getKillRegState(KillSrc)); } // This function returns true if a CR spill is necessary and false otherwise. bool PPCInstrInfo::StoreRegToStackSlot(MachineFunction &MF, unsigned SrcReg, bool isKill, int FrameIdx, const TargetRegisterClass *RC, SmallVectorImpl &NewMIs, bool &NonRI, bool &SpillsVRS) const{ // Note: If additional store instructions are added here, // update isStoreToStackSlot. DebugLoc DL; if (PPC::GPRCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STW)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); } else if (PPC::G8RCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STD)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); } else if (PPC::F8RCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STFD)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); } else if (PPC::F4RCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STFS)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); } else if (PPC::CRRCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::SPILL_CR)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); return true; } else if (PPC::CRBITRCRegClass.hasSubClassEq(RC)) { // FIXME: We use CRi here because there is no mtcrf on a bit. Since the // backend currently only uses CR1EQ as an individual bit, this should // not cause any bug. If we need other uses of CR bits, the following // code may be invalid. unsigned Reg = 0; if (SrcReg == PPC::CR0LT || SrcReg == PPC::CR0GT || SrcReg == PPC::CR0EQ || SrcReg == PPC::CR0UN) Reg = PPC::CR0; else if (SrcReg == PPC::CR1LT || SrcReg == PPC::CR1GT || SrcReg == PPC::CR1EQ || SrcReg == PPC::CR1UN) Reg = PPC::CR1; else if (SrcReg == PPC::CR2LT || SrcReg == PPC::CR2GT || SrcReg == PPC::CR2EQ || SrcReg == PPC::CR2UN) Reg = PPC::CR2; else if (SrcReg == PPC::CR3LT || SrcReg == PPC::CR3GT || SrcReg == PPC::CR3EQ || SrcReg == PPC::CR3UN) Reg = PPC::CR3; else if (SrcReg == PPC::CR4LT || SrcReg == PPC::CR4GT || SrcReg == PPC::CR4EQ || SrcReg == PPC::CR4UN) Reg = PPC::CR4; else if (SrcReg == PPC::CR5LT || SrcReg == PPC::CR5GT || SrcReg == PPC::CR5EQ || SrcReg == PPC::CR5UN) Reg = PPC::CR5; else if (SrcReg == PPC::CR6LT || SrcReg == PPC::CR6GT || SrcReg == PPC::CR6EQ || SrcReg == PPC::CR6UN) Reg = PPC::CR6; else if (SrcReg == PPC::CR7LT || SrcReg == PPC::CR7GT || SrcReg == PPC::CR7EQ || SrcReg == PPC::CR7UN) Reg = PPC::CR7; return StoreRegToStackSlot(MF, Reg, isKill, FrameIdx, &PPC::CRRCRegClass, NewMIs, NonRI, SpillsVRS); } else if (PPC::VRRCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::STVX)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); NonRI = true; } else if (PPC::VRSAVERCRegClass.hasSubClassEq(RC)) { assert(TM.getSubtargetImpl()->isDarwin() && "VRSAVE only needs spill/restore on Darwin"); NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::SPILL_VRSAVE)) .addReg(SrcReg, getKillRegState(isKill)), FrameIdx)); SpillsVRS = true; } else { llvm_unreachable("Unknown regclass!"); } return false; } void PPCInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned SrcReg, bool isKill, int FrameIdx, const TargetRegisterClass *RC, const TargetRegisterInfo *TRI) const { MachineFunction &MF = *MBB.getParent(); SmallVector NewMIs; PPCFunctionInfo *FuncInfo = MF.getInfo(); FuncInfo->setHasSpills(); bool NonRI = false, SpillsVRS = false; if (StoreRegToStackSlot(MF, SrcReg, isKill, FrameIdx, RC, NewMIs, NonRI, SpillsVRS)) FuncInfo->setSpillsCR(); if (SpillsVRS) FuncInfo->setSpillsVRSAVE(); if (NonRI) FuncInfo->setHasNonRISpills(); for (unsigned i = 0, e = NewMIs.size(); i != e; ++i) MBB.insert(MI, NewMIs[i]); const MachineFrameInfo &MFI = *MF.getFrameInfo(); MachineMemOperand *MMO = MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx), MachineMemOperand::MOStore, MFI.getObjectSize(FrameIdx), MFI.getObjectAlignment(FrameIdx)); NewMIs.back()->addMemOperand(MF, MMO); } bool PPCInstrInfo::LoadRegFromStackSlot(MachineFunction &MF, DebugLoc DL, unsigned DestReg, int FrameIdx, const TargetRegisterClass *RC, SmallVectorImpl &NewMIs, bool &NonRI, bool &SpillsVRS) const{ // Note: If additional load instructions are added here, // update isLoadFromStackSlot. if (PPC::GPRCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LWZ), DestReg), FrameIdx)); } else if (PPC::G8RCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LD), DestReg), FrameIdx)); } else if (PPC::F8RCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LFD), DestReg), FrameIdx)); } else if (PPC::F4RCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LFS), DestReg), FrameIdx)); } else if (PPC::CRRCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::RESTORE_CR), DestReg), FrameIdx)); return true; } else if (PPC::CRBITRCRegClass.hasSubClassEq(RC)) { unsigned Reg = 0; if (DestReg == PPC::CR0LT || DestReg == PPC::CR0GT || DestReg == PPC::CR0EQ || DestReg == PPC::CR0UN) Reg = PPC::CR0; else if (DestReg == PPC::CR1LT || DestReg == PPC::CR1GT || DestReg == PPC::CR1EQ || DestReg == PPC::CR1UN) Reg = PPC::CR1; else if (DestReg == PPC::CR2LT || DestReg == PPC::CR2GT || DestReg == PPC::CR2EQ || DestReg == PPC::CR2UN) Reg = PPC::CR2; else if (DestReg == PPC::CR3LT || DestReg == PPC::CR3GT || DestReg == PPC::CR3EQ || DestReg == PPC::CR3UN) Reg = PPC::CR3; else if (DestReg == PPC::CR4LT || DestReg == PPC::CR4GT || DestReg == PPC::CR4EQ || DestReg == PPC::CR4UN) Reg = PPC::CR4; else if (DestReg == PPC::CR5LT || DestReg == PPC::CR5GT || DestReg == PPC::CR5EQ || DestReg == PPC::CR5UN) Reg = PPC::CR5; else if (DestReg == PPC::CR6LT || DestReg == PPC::CR6GT || DestReg == PPC::CR6EQ || DestReg == PPC::CR6UN) Reg = PPC::CR6; else if (DestReg == PPC::CR7LT || DestReg == PPC::CR7GT || DestReg == PPC::CR7EQ || DestReg == PPC::CR7UN) Reg = PPC::CR7; return LoadRegFromStackSlot(MF, DL, Reg, FrameIdx, &PPC::CRRCRegClass, NewMIs, NonRI, SpillsVRS); } else if (PPC::VRRCRegClass.hasSubClassEq(RC)) { NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::LVX), DestReg), FrameIdx)); NonRI = true; } else if (PPC::VRSAVERCRegClass.hasSubClassEq(RC)) { assert(TM.getSubtargetImpl()->isDarwin() && "VRSAVE only needs spill/restore on Darwin"); NewMIs.push_back(addFrameReference(BuildMI(MF, DL, get(PPC::RESTORE_VRSAVE), DestReg), FrameIdx)); SpillsVRS = true; } else { llvm_unreachable("Unknown regclass!"); } return false; } void PPCInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned DestReg, int FrameIdx, const TargetRegisterClass *RC, const TargetRegisterInfo *TRI) const { MachineFunction &MF = *MBB.getParent(); SmallVector NewMIs; DebugLoc DL; if (MI != MBB.end()) DL = MI->getDebugLoc(); PPCFunctionInfo *FuncInfo = MF.getInfo(); FuncInfo->setHasSpills(); bool NonRI = false, SpillsVRS = false; if (LoadRegFromStackSlot(MF, DL, DestReg, FrameIdx, RC, NewMIs, NonRI, SpillsVRS)) FuncInfo->setSpillsCR(); if (SpillsVRS) FuncInfo->setSpillsVRSAVE(); if (NonRI) FuncInfo->setHasNonRISpills(); for (unsigned i = 0, e = NewMIs.size(); i != e; ++i) MBB.insert(MI, NewMIs[i]); const MachineFrameInfo &MFI = *MF.getFrameInfo(); MachineMemOperand *MMO = MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx), MachineMemOperand::MOLoad, MFI.getObjectSize(FrameIdx), MFI.getObjectAlignment(FrameIdx)); NewMIs.back()->addMemOperand(MF, MMO); } bool PPCInstrInfo:: ReverseBranchCondition(SmallVectorImpl &Cond) const { assert(Cond.size() == 2 && "Invalid PPC branch opcode!"); if (Cond[1].getReg() == PPC::CTR8 || Cond[1].getReg() == PPC::CTR) Cond[0].setImm(Cond[0].getImm() == 0 ? 1 : 0); else // Leave the CR# the same, but invert the condition. Cond[0].setImm(PPC::InvertPredicate((PPC::Predicate)Cond[0].getImm())); return false; } bool PPCInstrInfo::FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI, unsigned Reg, MachineRegisterInfo *MRI) const { // For some instructions, it is legal to fold ZERO into the RA register field. // A zero immediate should always be loaded with a single li. unsigned DefOpc = DefMI->getOpcode(); if (DefOpc != PPC::LI && DefOpc != PPC::LI8) return false; if (!DefMI->getOperand(1).isImm()) return false; if (DefMI->getOperand(1).getImm() != 0) return false; // Note that we cannot here invert the arguments of an isel in order to fold // a ZERO into what is presented as the second argument. All we have here // is the condition bit, and that might come from a CR-logical bit operation. const MCInstrDesc &UseMCID = UseMI->getDesc(); // Only fold into real machine instructions. if (UseMCID.isPseudo()) return false; unsigned UseIdx; for (UseIdx = 0; UseIdx < UseMI->getNumOperands(); ++UseIdx) if (UseMI->getOperand(UseIdx).isReg() && UseMI->getOperand(UseIdx).getReg() == Reg) break; assert(UseIdx < UseMI->getNumOperands() && "Cannot find Reg in UseMI"); assert(UseIdx < UseMCID.getNumOperands() && "No operand description for Reg"); const MCOperandInfo *UseInfo = &UseMCID.OpInfo[UseIdx]; // We can fold the zero if this register requires a GPRC_NOR0/G8RC_NOX0 // register (which might also be specified as a pointer class kind). if (UseInfo->isLookupPtrRegClass()) { if (UseInfo->RegClass /* Kind */ != 1) return false; } else { if (UseInfo->RegClass != PPC::GPRC_NOR0RegClassID && UseInfo->RegClass != PPC::G8RC_NOX0RegClassID) return false; } // Make sure this is not tied to an output register (or otherwise // constrained). This is true for ST?UX registers, for example, which // are tied to their output registers. if (UseInfo->Constraints != 0) return false; unsigned ZeroReg; if (UseInfo->isLookupPtrRegClass()) { bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); ZeroReg = isPPC64 ? PPC::ZERO8 : PPC::ZERO; } else { ZeroReg = UseInfo->RegClass == PPC::G8RC_NOX0RegClassID ? PPC::ZERO8 : PPC::ZERO; } bool DeleteDef = MRI->hasOneNonDBGUse(Reg); UseMI->getOperand(UseIdx).setReg(ZeroReg); if (DeleteDef) DefMI->eraseFromParent(); return true; } static bool MBBDefinesCTR(MachineBasicBlock &MBB) { for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end(); I != IE; ++I) if (I->definesRegister(PPC::CTR) || I->definesRegister(PPC::CTR8)) return true; return false; } // We should make sure that, if we're going to predicate both sides of a // condition (a diamond), that both sides don't define the counter register. We // can predicate counter-decrement-based branches, but while that predicates // the branching, it does not predicate the counter decrement. If we tried to // merge the triangle into one predicated block, we'd decrement the counter // twice. bool PPCInstrInfo::isProfitableToIfCvt(MachineBasicBlock &TMBB, unsigned NumT, unsigned ExtraT, MachineBasicBlock &FMBB, unsigned NumF, unsigned ExtraF, const BranchProbability &Probability) const { return !(MBBDefinesCTR(TMBB) && MBBDefinesCTR(FMBB)); } bool PPCInstrInfo::isPredicated(const MachineInstr *MI) const { // The predicated branches are identified by their type, not really by the // explicit presence of a predicate. Furthermore, some of them can be // predicated more than once. Because if conversion won't try to predicate // any instruction which already claims to be predicated (by returning true // here), always return false. In doing so, we let isPredicable() be the // final word on whether not the instruction can be (further) predicated. return false; } bool PPCInstrInfo::isUnpredicatedTerminator(const MachineInstr *MI) const { if (!MI->isTerminator()) return false; // Conditional branch is a special case. if (MI->isBranch() && !MI->isBarrier()) return true; return !isPredicated(MI); } bool PPCInstrInfo::PredicateInstruction( MachineInstr *MI, const SmallVectorImpl &Pred) const { unsigned OpC = MI->getOpcode(); if (OpC == PPC::BLR) { if (Pred[1].getReg() == PPC::CTR8 || Pred[1].getReg() == PPC::CTR) { bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); MI->setDesc(get(Pred[0].getImm() ? (isPPC64 ? PPC::BDNZLR8 : PPC::BDNZLR) : (isPPC64 ? PPC::BDZLR8 : PPC::BDZLR))); } else { MI->setDesc(get(PPC::BCLR)); MachineInstrBuilder(*MI->getParent()->getParent(), MI) .addImm(Pred[0].getImm()) .addReg(Pred[1].getReg()); } return true; } else if (OpC == PPC::B) { if (Pred[1].getReg() == PPC::CTR8 || Pred[1].getReg() == PPC::CTR) { bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); MI->setDesc(get(Pred[0].getImm() ? (isPPC64 ? PPC::BDNZ8 : PPC::BDNZ) : (isPPC64 ? PPC::BDZ8 : PPC::BDZ))); } else { MachineBasicBlock *MBB = MI->getOperand(0).getMBB(); MI->RemoveOperand(0); MI->setDesc(get(PPC::BCC)); MachineInstrBuilder(*MI->getParent()->getParent(), MI) .addImm(Pred[0].getImm()) .addReg(Pred[1].getReg()) .addMBB(MBB); } return true; } else if (OpC == PPC::BCTR || OpC == PPC::BCTR8 || OpC == PPC::BCTRL || OpC == PPC::BCTRL8) { if (Pred[1].getReg() == PPC::CTR8 || Pred[1].getReg() == PPC::CTR) llvm_unreachable("Cannot predicate bctr[l] on the ctr register"); bool setLR = OpC == PPC::BCTRL || OpC == PPC::BCTRL8; bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); MI->setDesc(get(isPPC64 ? (setLR ? PPC::BCCTRL8 : PPC::BCCTR8) : (setLR ? PPC::BCCTRL : PPC::BCCTR))); MachineInstrBuilder(*MI->getParent()->getParent(), MI) .addImm(Pred[0].getImm()) .addReg(Pred[1].getReg()); return true; } return false; } bool PPCInstrInfo::SubsumesPredicate( const SmallVectorImpl &Pred1, const SmallVectorImpl &Pred2) const { assert(Pred1.size() == 2 && "Invalid PPC first predicate"); assert(Pred2.size() == 2 && "Invalid PPC second predicate"); if (Pred1[1].getReg() == PPC::CTR8 || Pred1[1].getReg() == PPC::CTR) return false; if (Pred2[1].getReg() == PPC::CTR8 || Pred2[1].getReg() == PPC::CTR) return false; // P1 can only subsume P2 if they test the same condition register. if (Pred1[1].getReg() != Pred2[1].getReg()) return false; PPC::Predicate P1 = (PPC::Predicate) Pred1[0].getImm(); PPC::Predicate P2 = (PPC::Predicate) Pred2[0].getImm(); if (P1 == P2) return true; // Does P1 subsume P2, e.g. GE subsumes GT. if (P1 == PPC::PRED_LE && (P2 == PPC::PRED_LT || P2 == PPC::PRED_EQ)) return true; if (P1 == PPC::PRED_GE && (P2 == PPC::PRED_GT || P2 == PPC::PRED_EQ)) return true; return false; } bool PPCInstrInfo::DefinesPredicate(MachineInstr *MI, std::vector &Pred) const { // Note: At the present time, the contents of Pred from this function is // unused by IfConversion. This implementation follows ARM by pushing the // CR-defining operand. Because the 'DZ' and 'DNZ' count as types of // predicate, instructions defining CTR or CTR8 are also included as // predicate-defining instructions. const TargetRegisterClass *RCs[] = { &PPC::CRRCRegClass, &PPC::CRBITRCRegClass, &PPC::CTRRCRegClass, &PPC::CTRRC8RegClass }; bool Found = false; for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { const MachineOperand &MO = MI->getOperand(i); for (unsigned c = 0; c < array_lengthof(RCs) && !Found; ++c) { const TargetRegisterClass *RC = RCs[c]; if (MO.isReg()) { if (MO.isDef() && RC->contains(MO.getReg())) { Pred.push_back(MO); Found = true; } } else if (MO.isRegMask()) { for (TargetRegisterClass::iterator I = RC->begin(), IE = RC->end(); I != IE; ++I) if (MO.clobbersPhysReg(*I)) { Pred.push_back(MO); Found = true; } } } } return Found; } bool PPCInstrInfo::isPredicable(MachineInstr *MI) const { unsigned OpC = MI->getOpcode(); switch (OpC) { default: return false; case PPC::B: case PPC::BLR: case PPC::BCTR: case PPC::BCTR8: case PPC::BCTRL: case PPC::BCTRL8: return true; } } bool PPCInstrInfo::analyzeCompare(const MachineInstr *MI, unsigned &SrcReg, unsigned &SrcReg2, int &Mask, int &Value) const { unsigned Opc = MI->getOpcode(); switch (Opc) { default: return false; case PPC::CMPWI: case PPC::CMPLWI: case PPC::CMPDI: case PPC::CMPLDI: SrcReg = MI->getOperand(1).getReg(); SrcReg2 = 0; Value = MI->getOperand(2).getImm(); Mask = 0xFFFF; return true; case PPC::CMPW: case PPC::CMPLW: case PPC::CMPD: case PPC::CMPLD: case PPC::FCMPUS: case PPC::FCMPUD: SrcReg = MI->getOperand(1).getReg(); SrcReg2 = MI->getOperand(2).getReg(); return true; } } bool PPCInstrInfo::optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2, int Mask, int Value, const MachineRegisterInfo *MRI) const { if (DisableCmpOpt) return false; int OpC = CmpInstr->getOpcode(); unsigned CRReg = CmpInstr->getOperand(0).getReg(); // FP record forms set CR1 based on the execption status bits, not a // comparison with zero. if (OpC == PPC::FCMPUS || OpC == PPC::FCMPUD) return false; // The record forms set the condition register based on a signed comparison // with zero (so says the ISA manual). This is not as straightforward as it // seems, however, because this is always a 64-bit comparison on PPC64, even // for instructions that are 32-bit in nature (like slw for example). // So, on PPC32, for unsigned comparisons, we can use the record forms only // for equality checks (as those don't depend on the sign). On PPC64, // we are restricted to equality for unsigned 64-bit comparisons and for // signed 32-bit comparisons the applicability is more restricted. bool isPPC64 = TM.getSubtargetImpl()->isPPC64(); bool is32BitSignedCompare = OpC == PPC::CMPWI || OpC == PPC::CMPW; bool is32BitUnsignedCompare = OpC == PPC::CMPLWI || OpC == PPC::CMPLW; bool is64BitUnsignedCompare = OpC == PPC::CMPLDI || OpC == PPC::CMPLD; // Get the unique definition of SrcReg. MachineInstr *MI = MRI->getUniqueVRegDef(SrcReg); if (!MI) return false; int MIOpC = MI->getOpcode(); bool equalityOnly = false; bool noSub = false; if (isPPC64) { if (is32BitSignedCompare) { // We can perform this optimization only if MI is sign-extending. if (MIOpC == PPC::SRAW || MIOpC == PPC::SRAWo || MIOpC == PPC::SRAWI || MIOpC == PPC::SRAWIo || MIOpC == PPC::EXTSB || MIOpC == PPC::EXTSBo || MIOpC == PPC::EXTSH || MIOpC == PPC::EXTSHo || MIOpC == PPC::EXTSW || MIOpC == PPC::EXTSWo) { noSub = true; } else return false; } else if (is32BitUnsignedCompare) { // We can perform this optimization, equality only, if MI is // zero-extending. if (MIOpC == PPC::CNTLZW || MIOpC == PPC::CNTLZWo || MIOpC == PPC::SLW || MIOpC == PPC::SLWo || MIOpC == PPC::SRW || MIOpC == PPC::SRWo) { noSub = true; equalityOnly = true; } else return false; } else equalityOnly = is64BitUnsignedCompare; } else equalityOnly = is32BitUnsignedCompare; if (equalityOnly) { // We need to check the uses of the condition register in order to reject // non-equality comparisons. for (MachineRegisterInfo::use_iterator I = MRI->use_begin(CRReg), IE = MRI->use_end(); I != IE; ++I) { MachineInstr *UseMI = &*I; if (UseMI->getOpcode() == PPC::BCC) { unsigned Pred = UseMI->getOperand(0).getImm(); if (Pred != PPC::PRED_EQ && Pred != PPC::PRED_NE) return false; } else if (UseMI->getOpcode() == PPC::ISEL || UseMI->getOpcode() == PPC::ISEL8) { unsigned SubIdx = UseMI->getOperand(3).getSubReg(); if (SubIdx != PPC::sub_eq) return false; } else return false; } } MachineBasicBlock::iterator I = CmpInstr; // Scan forward to find the first use of the compare. for (MachineBasicBlock::iterator EL = CmpInstr->getParent()->end(); I != EL; ++I) { bool FoundUse = false; for (MachineRegisterInfo::use_iterator J = MRI->use_begin(CRReg), JE = MRI->use_end(); J != JE; ++J) if (&*J == &*I) { FoundUse = true; break; } if (FoundUse) break; } // There are two possible candidates which can be changed to set CR[01]. // One is MI, the other is a SUB instruction. // For CMPrr(r1,r2), we are looking for SUB(r1,r2) or SUB(r2,r1). MachineInstr *Sub = NULL; if (SrcReg2 != 0) // MI is not a candidate for CMPrr. MI = NULL; // FIXME: Conservatively refuse to convert an instruction which isn't in the // same BB as the comparison. This is to allow the check below to avoid calls // (and other explicit clobbers); instead we should really check for these // more explicitly (in at least a few predecessors). else if (MI->getParent() != CmpInstr->getParent() || Value != 0) { // PPC does not have a record-form SUBri. return false; } // Search for Sub. const TargetRegisterInfo *TRI = &getRegisterInfo(); --I; // Get ready to iterate backward from CmpInstr. MachineBasicBlock::iterator E = MI, B = CmpInstr->getParent()->begin(); for (; I != E && !noSub; --I) { const MachineInstr &Instr = *I; unsigned IOpC = Instr.getOpcode(); if (&*I != CmpInstr && ( Instr.modifiesRegister(PPC::CR0, TRI) || Instr.readsRegister(PPC::CR0, TRI))) // This instruction modifies or uses the record condition register after // the one we want to change. While we could do this transformation, it // would likely not be profitable. This transformation removes one // instruction, and so even forcing RA to generate one move probably // makes it unprofitable. return false; // Check whether CmpInstr can be made redundant by the current instruction. if ((OpC == PPC::CMPW || OpC == PPC::CMPLW || OpC == PPC::CMPD || OpC == PPC::CMPLD) && (IOpC == PPC::SUBF || IOpC == PPC::SUBF8) && ((Instr.getOperand(1).getReg() == SrcReg && Instr.getOperand(2).getReg() == SrcReg2) || (Instr.getOperand(1).getReg() == SrcReg2 && Instr.getOperand(2).getReg() == SrcReg))) { Sub = &*I; break; } if (I == B) // The 'and' is below the comparison instruction. return false; } // Return false if no candidates exist. if (!MI && !Sub) return false; // The single candidate is called MI. if (!MI) MI = Sub; int NewOpC = -1; MIOpC = MI->getOpcode(); if (MIOpC == PPC::ANDIo || MIOpC == PPC::ANDIo8) NewOpC = MIOpC; else { NewOpC = PPC::getRecordFormOpcode(MIOpC); if (NewOpC == -1 && PPC::getNonRecordFormOpcode(MIOpC) != -1) NewOpC = MIOpC; } // FIXME: On the non-embedded POWER architectures, only some of the record // forms are fast, and we should use only the fast ones. // The defining instruction has a record form (or is already a record // form). It is possible, however, that we'll need to reverse the condition // code of the users. if (NewOpC == -1) return false; SmallVector, 4> PredsToUpdate; SmallVector, 4> SubRegsToUpdate; // If we have SUB(r1, r2) and CMP(r2, r1), the condition code based on CMP // needs to be updated to be based on SUB. Push the condition code // operands to OperandsToUpdate. If it is safe to remove CmpInstr, the // condition code of these operands will be modified. bool ShouldSwap = false; if (Sub) { ShouldSwap = SrcReg2 != 0 && Sub->getOperand(1).getReg() == SrcReg2 && Sub->getOperand(2).getReg() == SrcReg; // The operands to subf are the opposite of sub, so only in the fixed-point // case, invert the order. ShouldSwap = !ShouldSwap; } if (ShouldSwap) for (MachineRegisterInfo::use_iterator I = MRI->use_begin(CRReg), IE = MRI->use_end(); I != IE; ++I) { MachineInstr *UseMI = &*I; if (UseMI->getOpcode() == PPC::BCC) { PPC::Predicate Pred = (PPC::Predicate) UseMI->getOperand(0).getImm(); assert((!equalityOnly || Pred == PPC::PRED_EQ || Pred == PPC::PRED_NE) && "Invalid predicate for equality-only optimization"); PredsToUpdate.push_back(std::make_pair(&((*I).getOperand(0)), PPC::getSwappedPredicate(Pred))); } else if (UseMI->getOpcode() == PPC::ISEL || UseMI->getOpcode() == PPC::ISEL8) { unsigned NewSubReg = UseMI->getOperand(3).getSubReg(); assert((!equalityOnly || NewSubReg == PPC::sub_eq) && "Invalid CR bit for equality-only optimization"); if (NewSubReg == PPC::sub_lt) NewSubReg = PPC::sub_gt; else if (NewSubReg == PPC::sub_gt) NewSubReg = PPC::sub_lt; SubRegsToUpdate.push_back(std::make_pair(&((*I).getOperand(3)), NewSubReg)); } else // We need to abort on a user we don't understand. return false; } // Create a new virtual register to hold the value of the CR set by the // record-form instruction. If the instruction was not previously in // record form, then set the kill flag on the CR. CmpInstr->eraseFromParent(); MachineBasicBlock::iterator MII = MI; BuildMI(*MI->getParent(), llvm::next(MII), MI->getDebugLoc(), get(TargetOpcode::COPY), CRReg) .addReg(PPC::CR0, MIOpC != NewOpC ? RegState::Kill : 0); if (MIOpC != NewOpC) { // We need to be careful here: we're replacing one instruction with // another, and we need to make sure that we get all of the right // implicit uses and defs. On the other hand, the caller may be holding // an iterator to this instruction, and so we can't delete it (this is // specifically the case if this is the instruction directly after the // compare). const MCInstrDesc &NewDesc = get(NewOpC); MI->setDesc(NewDesc); if (NewDesc.ImplicitDefs) for (const uint16_t *ImpDefs = NewDesc.getImplicitDefs(); *ImpDefs; ++ImpDefs) if (!MI->definesRegister(*ImpDefs)) MI->addOperand(*MI->getParent()->getParent(), MachineOperand::CreateReg(*ImpDefs, true, true)); if (NewDesc.ImplicitUses) for (const uint16_t *ImpUses = NewDesc.getImplicitUses(); *ImpUses; ++ImpUses) if (!MI->readsRegister(*ImpUses)) MI->addOperand(*MI->getParent()->getParent(), MachineOperand::CreateReg(*ImpUses, false, true)); } // Modify the condition code of operands in OperandsToUpdate. // Since we have SUB(r1, r2) and CMP(r2, r1), the condition code needs to // be changed from r2 > r1 to r1 < r2, from r2 < r1 to r1 > r2, etc. for (unsigned i = 0, e = PredsToUpdate.size(); i < e; i++) PredsToUpdate[i].first->setImm(PredsToUpdate[i].second); for (unsigned i = 0, e = SubRegsToUpdate.size(); i < e; i++) SubRegsToUpdate[i].first->setSubReg(SubRegsToUpdate[i].second); return true; } /// GetInstSize - Return the number of bytes of code the specified /// instruction may be. This returns the maximum number of bytes. /// unsigned PPCInstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const { switch (MI->getOpcode()) { case PPC::INLINEASM: { // Inline Asm: Variable size. const MachineFunction *MF = MI->getParent()->getParent(); const char *AsmStr = MI->getOperand(0).getSymbolName(); return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo()); } case PPC::PROLOG_LABEL: case PPC::EH_LABEL: case PPC::GC_LABEL: case PPC::DBG_VALUE: return 0; case PPC::BL8_NOP: case PPC::BLA8_NOP: return 8; default: return 4; // PowerPC instructions are all 4 bytes } } #undef DEBUG_TYPE #define DEBUG_TYPE "ppc-early-ret" STATISTIC(NumBCLR, "Number of early conditional returns"); STATISTIC(NumBLR, "Number of early returns"); namespace llvm { void initializePPCEarlyReturnPass(PassRegistry&); } namespace { // PPCEarlyReturn pass - For simple functions without epilogue code, move // returns up, and create conditional returns, to avoid unnecessary // branch-to-blr sequences. struct PPCEarlyReturn : public MachineFunctionPass { static char ID; PPCEarlyReturn() : MachineFunctionPass(ID) { initializePPCEarlyReturnPass(*PassRegistry::getPassRegistry()); } const PPCTargetMachine *TM; const PPCInstrInfo *TII; protected: bool processBlock(MachineBasicBlock &ReturnMBB) { bool Changed = false; MachineBasicBlock::iterator I = ReturnMBB.begin(); I = ReturnMBB.SkipPHIsAndLabels(I); // The block must be essentially empty except for the blr. if (I == ReturnMBB.end() || I->getOpcode() != PPC::BLR || I != ReturnMBB.getLastNonDebugInstr()) return Changed; SmallVector PredToRemove; for (MachineBasicBlock::pred_iterator PI = ReturnMBB.pred_begin(), PIE = ReturnMBB.pred_end(); PI != PIE; ++PI) { bool OtherReference = false, BlockChanged = false; for (MachineBasicBlock::iterator J = (*PI)->getLastNonDebugInstr();;) { if (J->getOpcode() == PPC::B) { if (J->getOperand(0).getMBB() == &ReturnMBB) { // This is an unconditional branch to the return. Replace the // branch with a blr. BuildMI(**PI, J, J->getDebugLoc(), TII->get(PPC::BLR)); MachineBasicBlock::iterator K = J--; K->eraseFromParent(); BlockChanged = true; ++NumBLR; continue; } } else if (J->getOpcode() == PPC::BCC) { if (J->getOperand(2).getMBB() == &ReturnMBB) { // This is a conditional branch to the return. Replace the branch // with a bclr. BuildMI(**PI, J, J->getDebugLoc(), TII->get(PPC::BCLR)) .addImm(J->getOperand(0).getImm()) .addReg(J->getOperand(1).getReg()); MachineBasicBlock::iterator K = J--; K->eraseFromParent(); BlockChanged = true; ++NumBCLR; continue; } } else if (J->isBranch()) { if (J->isIndirectBranch()) { if (ReturnMBB.hasAddressTaken()) OtherReference = true; } else for (unsigned i = 0; i < J->getNumOperands(); ++i) if (J->getOperand(i).isMBB() && J->getOperand(i).getMBB() == &ReturnMBB) OtherReference = true; } else if (!J->isTerminator() && !J->isDebugValue()) break; if (J == (*PI)->begin()) break; --J; } if ((*PI)->canFallThrough() && (*PI)->isLayoutSuccessor(&ReturnMBB)) OtherReference = true; // Predecessors are stored in a vector and can't be removed here. if (!OtherReference && BlockChanged) { PredToRemove.push_back(*PI); } if (BlockChanged) Changed = true; } for (unsigned i = 0, ie = PredToRemove.size(); i != ie; ++i) PredToRemove[i]->removeSuccessor(&ReturnMBB); if (Changed && !ReturnMBB.hasAddressTaken()) { // We now might be able to merge this blr-only block into its // by-layout predecessor. if (ReturnMBB.pred_size() == 1 && (*ReturnMBB.pred_begin())->isLayoutSuccessor(&ReturnMBB)) { // Move the blr into the preceding block. MachineBasicBlock &PrevMBB = **ReturnMBB.pred_begin(); PrevMBB.splice(PrevMBB.end(), &ReturnMBB, I); PrevMBB.removeSuccessor(&ReturnMBB); } if (ReturnMBB.pred_empty()) ReturnMBB.eraseFromParent(); } return Changed; } public: virtual bool runOnMachineFunction(MachineFunction &MF) { TM = static_cast(&MF.getTarget()); TII = TM->getInstrInfo(); bool Changed = false; // If the function does not have at least two blocks, then there is // nothing to do. if (MF.size() < 2) return Changed; for (MachineFunction::iterator I = MF.begin(); I != MF.end();) { MachineBasicBlock &B = *I++; if (processBlock(B)) Changed = true; } return Changed; } virtual void getAnalysisUsage(AnalysisUsage &AU) const { MachineFunctionPass::getAnalysisUsage(AU); } }; } INITIALIZE_PASS(PPCEarlyReturn, DEBUG_TYPE, "PowerPC Early-Return Creation", false, false) char PPCEarlyReturn::ID = 0; FunctionPass* llvm::createPPCEarlyReturnPass() { return new PPCEarlyReturn(); }