MachineInstr * LanaiInstrInfo::optimizeSelect(MachineInstr &MI, SmallPtrSetImpl<MachineInstr *> &SeenMIs, bool PreferFalse) const { assert(MI.getOpcode() == Lanai::SELECT && "unknown select instruction"); MachineRegisterInfo &MRI = MI.getParent()->getParent()->getRegInfo(); MachineInstr *DefMI = canFoldIntoSelect(MI.getOperand(1).getReg(), MRI, this); bool Invert = !DefMI; if (!DefMI) DefMI = canFoldIntoSelect(MI.getOperand(2).getReg(), MRI, this); if (!DefMI) return nullptr; // Find new register class to use. MachineOperand FalseReg = MI.getOperand(Invert ? 1 : 2); unsigned DestReg = MI.getOperand(0).getReg(); const TargetRegisterClass *PreviousClass = MRI.getRegClass(FalseReg.getReg()); if (!MRI.constrainRegClass(DestReg, PreviousClass)) return nullptr; // Create a new predicated version of DefMI. MachineInstrBuilder NewMI = BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), DefMI->getDesc(), DestReg); // Copy all the DefMI operands, excluding its (null) predicate. const MCInstrDesc &DefDesc = DefMI->getDesc(); for (unsigned i = 1, e = DefDesc.getNumOperands(); i != e && !DefDesc.OpInfo[i].isPredicate(); ++i) NewMI.addOperand(DefMI->getOperand(i)); unsigned CondCode = MI.getOperand(3).getImm(); if (Invert) NewMI.addImm(getOppositeCondition(LPCC::CondCode(CondCode))); else NewMI.addImm(CondCode); NewMI.copyImplicitOps(MI); // The output register value when the predicate is false is an implicit // register operand tied to the first def. The tie makes the register // allocator ensure the FalseReg is allocated the same register as operand 0. FalseReg.setImplicit(); NewMI.addOperand(FalseReg); NewMI->tieOperands(0, NewMI->getNumOperands() - 1); // Update SeenMIs set: register newly created MI and erase removed DefMI. SeenMIs.insert(NewMI); SeenMIs.erase(DefMI); // If MI is inside a loop, and DefMI is outside the loop, then kill flags on // DefMI would be invalid when transferred inside the loop. Checking for a // loop is expensive, but at least remove kill flags if they are in different // BBs. if (DefMI->getParent() != MI.getParent()) NewMI->clearKillInfo(); // The caller will erase MI, but not DefMI. DefMI->eraseFromParent(); return NewMI; }
// Because of how EmitCmp is called with fast-isel, you can // end up with redundant "andi" instructions after the sequences emitted below. // We should try and solve this issue in the future. // bool MipsFastISel::emitCmp(unsigned ResultReg, const CmpInst *CI) { const Value *Left = CI->getOperand(0), *Right = CI->getOperand(1); bool IsUnsigned = CI->isUnsigned(); unsigned LeftReg = getRegEnsuringSimpleIntegerWidening(Left, IsUnsigned); if (LeftReg == 0) return false; unsigned RightReg = getRegEnsuringSimpleIntegerWidening(Right, IsUnsigned); if (RightReg == 0) return false; CmpInst::Predicate P = CI->getPredicate(); switch (P) { default: return false; case CmpInst::ICMP_EQ: { unsigned TempReg = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::XOR, TempReg).addReg(LeftReg).addReg(RightReg); emitInst(Mips::SLTiu, ResultReg).addReg(TempReg).addImm(1); break; } case CmpInst::ICMP_NE: { unsigned TempReg = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::XOR, TempReg).addReg(LeftReg).addReg(RightReg); emitInst(Mips::SLTu, ResultReg).addReg(Mips::ZERO).addReg(TempReg); break; } case CmpInst::ICMP_UGT: { emitInst(Mips::SLTu, ResultReg).addReg(RightReg).addReg(LeftReg); break; } case CmpInst::ICMP_ULT: { emitInst(Mips::SLTu, ResultReg).addReg(LeftReg).addReg(RightReg); break; } case CmpInst::ICMP_UGE: { unsigned TempReg = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::SLTu, TempReg).addReg(LeftReg).addReg(RightReg); emitInst(Mips::XORi, ResultReg).addReg(TempReg).addImm(1); break; } case CmpInst::ICMP_ULE: { unsigned TempReg = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::SLTu, TempReg).addReg(RightReg).addReg(LeftReg); emitInst(Mips::XORi, ResultReg).addReg(TempReg).addImm(1); break; } case CmpInst::ICMP_SGT: { emitInst(Mips::SLT, ResultReg).addReg(RightReg).addReg(LeftReg); break; } case CmpInst::ICMP_SLT: { emitInst(Mips::SLT, ResultReg).addReg(LeftReg).addReg(RightReg); break; } case CmpInst::ICMP_SGE: { unsigned TempReg = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::SLT, TempReg).addReg(LeftReg).addReg(RightReg); emitInst(Mips::XORi, ResultReg).addReg(TempReg).addImm(1); break; } case CmpInst::ICMP_SLE: { unsigned TempReg = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::SLT, TempReg).addReg(RightReg).addReg(LeftReg); emitInst(Mips::XORi, ResultReg).addReg(TempReg).addImm(1); break; } case CmpInst::FCMP_OEQ: case CmpInst::FCMP_UNE: case CmpInst::FCMP_OLT: case CmpInst::FCMP_OLE: case CmpInst::FCMP_OGT: case CmpInst::FCMP_OGE: { if (UnsupportedFPMode) return false; bool IsFloat = Left->getType()->isFloatTy(); bool IsDouble = Left->getType()->isDoubleTy(); if (!IsFloat && !IsDouble) return false; unsigned Opc, CondMovOpc; switch (P) { case CmpInst::FCMP_OEQ: Opc = IsFloat ? Mips::C_EQ_S : Mips::C_EQ_D32; CondMovOpc = Mips::MOVT_I; break; case CmpInst::FCMP_UNE: Opc = IsFloat ? Mips::C_EQ_S : Mips::C_EQ_D32; CondMovOpc = Mips::MOVF_I; break; case CmpInst::FCMP_OLT: Opc = IsFloat ? Mips::C_OLT_S : Mips::C_OLT_D32; CondMovOpc = Mips::MOVT_I; break; case CmpInst::FCMP_OLE: Opc = IsFloat ? Mips::C_OLE_S : Mips::C_OLE_D32; CondMovOpc = Mips::MOVT_I; break; case CmpInst::FCMP_OGT: Opc = IsFloat ? Mips::C_ULE_S : Mips::C_ULE_D32; CondMovOpc = Mips::MOVF_I; break; case CmpInst::FCMP_OGE: Opc = IsFloat ? Mips::C_ULT_S : Mips::C_ULT_D32; CondMovOpc = Mips::MOVF_I; break; default: llvm_unreachable("Only switching of a subset of CCs."); } unsigned RegWithZero = createResultReg(&Mips::GPR32RegClass); unsigned RegWithOne = createResultReg(&Mips::GPR32RegClass); emitInst(Mips::ADDiu, RegWithZero).addReg(Mips::ZERO).addImm(0); emitInst(Mips::ADDiu, RegWithOne).addReg(Mips::ZERO).addImm(1); emitInst(Opc).addReg(LeftReg).addReg(RightReg).addReg( Mips::FCC0, RegState::ImplicitDefine); MachineInstrBuilder MI = emitInst(CondMovOpc, ResultReg) .addReg(RegWithOne) .addReg(Mips::FCC0) .addReg(RegWithZero, RegState::Implicit); MI->tieOperands(0, 3); break; } } return true; }
/// EmitSpecialNode - Generate machine code for a target-independent node and /// needed dependencies. void InstrEmitter:: EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, DenseMap<SDValue, unsigned> &VRBaseMap) { switch (Node->getOpcode()) { default: #ifndef NDEBUG Node->dump(); #endif llvm_unreachable("This target-independent node should have been selected!"); case ISD::EntryToken: llvm_unreachable("EntryToken should have been excluded from the schedule!"); case ISD::MERGE_VALUES: case ISD::TokenFactor: // fall thru break; case ISD::CopyToReg: { unsigned SrcReg; SDValue SrcVal = Node->getOperand(2); if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal)) SrcReg = R->getReg(); else SrcReg = getVR(SrcVal, VRBaseMap); unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); if (SrcReg == DestReg) // Coalesced away the copy? Ignore. break; BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), DestReg).addReg(SrcReg); break; } case ISD::CopyFromReg: { unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap); break; } case ISD::EH_LABEL: case ISD::ANNOTATION_LABEL: { unsigned Opc = (Node->getOpcode() == ISD::EH_LABEL) ? TargetOpcode::EH_LABEL : TargetOpcode::ANNOTATION_LABEL; MCSymbol *S = cast<LabelSDNode>(Node)->getLabel(); BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(Opc)).addSym(S); break; } case ISD::LIFETIME_START: case ISD::LIFETIME_END: { unsigned TarOp = (Node->getOpcode() == ISD::LIFETIME_START) ? TargetOpcode::LIFETIME_START : TargetOpcode::LIFETIME_END; FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Node->getOperand(1)); BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp)) .addFrameIndex(FI->getIndex()); break; } case ISD::INLINEASM: { unsigned NumOps = Node->getNumOperands(); if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue) --NumOps; // Ignore the glue operand. // Create the inline asm machine instruction. MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), TII->get(TargetOpcode::INLINEASM)); // Add the asm string as an external symbol operand. SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString); const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol(); MIB.addExternalSymbol(AsmStr); // Add the HasSideEffect, isAlignStack, AsmDialect, MayLoad and MayStore // bits. int64_t ExtraInfo = cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))-> getZExtValue(); MIB.addImm(ExtraInfo); // Remember to operand index of the group flags. SmallVector<unsigned, 8> GroupIdx; // Remember registers that are part of early-clobber defs. SmallVector<unsigned, 8> ECRegs; // Add all of the operand registers to the instruction. for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) { unsigned Flags = cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue(); const unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); GroupIdx.push_back(MIB->getNumOperands()); MIB.addImm(Flags); ++i; // Skip the ID value. switch (InlineAsm::getKind(Flags)) { default: llvm_unreachable("Bad flags!"); case InlineAsm::Kind_RegDef: for (unsigned j = 0; j != NumVals; ++j, ++i) { unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); // FIXME: Add dead flags for physical and virtual registers defined. // For now, mark physical register defs as implicit to help fast // regalloc. This makes inline asm look a lot like calls. MIB.addReg(Reg, RegState::Define | getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg))); } break; case InlineAsm::Kind_RegDefEarlyClobber: case InlineAsm::Kind_Clobber: for (unsigned j = 0; j != NumVals; ++j, ++i) { unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); MIB.addReg(Reg, RegState::Define | RegState::EarlyClobber | getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg))); ECRegs.push_back(Reg); } break; case InlineAsm::Kind_RegUse: // Use of register. case InlineAsm::Kind_Imm: // Immediate. case InlineAsm::Kind_Mem: // Addressing mode. // The addressing mode has been selected, just add all of the // operands to the machine instruction. for (unsigned j = 0; j != NumVals; ++j, ++i) AddOperand(MIB, Node->getOperand(i), 0, nullptr, VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned); // Manually set isTied bits. if (InlineAsm::getKind(Flags) == InlineAsm::Kind_RegUse) { unsigned DefGroup = 0; if (InlineAsm::isUseOperandTiedToDef(Flags, DefGroup)) { unsigned DefIdx = GroupIdx[DefGroup] + 1; unsigned UseIdx = GroupIdx.back() + 1; for (unsigned j = 0; j != NumVals; ++j) MIB->tieOperands(DefIdx + j, UseIdx + j); } } break; } } // GCC inline assembly allows input operands to also be early-clobber // output operands (so long as the operand is written only after it's // used), but this does not match the semantics of our early-clobber flag. // If an early-clobber operand register is also an input operand register, // then remove the early-clobber flag. for (unsigned Reg : ECRegs) { if (MIB->readsRegister(Reg, TRI)) { MachineOperand *MO = MIB->findRegisterDefOperand(Reg, false, TRI); assert(MO && "No def operand for clobbered register?"); MO->setIsEarlyClobber(false); } } // Get the mdnode from the asm if it exists and add it to the instruction. SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode); const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD(); if (MD) MIB.addMetadata(MD); MBB->insert(InsertPos, MIB); break; } } }