//===-- LegalizeDAG.cpp - Implement SelectionDAG::Legalize ----------------===// // // The LLVM Compiler Infrastructure // // This file was developed by the LLVM research group and is distributed under // the University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the SelectionDAG::Legalize method. // //===----------------------------------------------------------------------===// #include "llvm/CodeGen/SelectionDAG.h" #include "llvm/CodeGen/MachineConstantPool.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/Target/TargetLowering.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetOptions.h" #include "llvm/Constants.h" #include using namespace llvm; //===----------------------------------------------------------------------===// /// SelectionDAGLegalize - This takes an arbitrary SelectionDAG as input and /// hacks on it until the target machine can handle it. This involves /// eliminating value sizes the machine cannot handle (promoting small sizes to /// large sizes or splitting up large values into small values) as well as /// eliminating operations the machine cannot handle. /// /// This code also does a small amount of optimization and recognition of idioms /// as part of its processing. For example, if a target does not support a /// 'setcc' instruction efficiently, but does support 'brcc' instruction, this /// will attempt merge setcc and brc instructions into brcc's. /// namespace { class SelectionDAGLegalize { TargetLowering &TLI; SelectionDAG &DAG; /// LegalizeAction - This enum indicates what action we should take for each /// value type the can occur in the program. enum LegalizeAction { Legal, // The target natively supports this value type. Promote, // This should be promoted to the next larger type. Expand, // This integer type should be broken into smaller pieces. }; /// TransformToType - For any value types we are promoting or expanding, this /// contains the value type that we are changing to. For Expanded types, this /// contains one step of the expand (e.g. i64 -> i32), even if there are /// multiple steps required (e.g. i64 -> i16) MVT::ValueType TransformToType[MVT::LAST_VALUETYPE]; /// ValueTypeActions - This is a bitvector that contains two bits for each /// value type, where the two bits correspond to the LegalizeAction enum. /// This can be queried with "getTypeAction(VT)". unsigned ValueTypeActions; /// NeedsAnotherIteration - This is set when we expand a large integer /// operation into smaller integer operations, but the smaller operations are /// not set. This occurs only rarely in practice, for targets that don't have /// 32-bit or larger integer registers. bool NeedsAnotherIteration; /// LegalizedNodes - For nodes that are of legal width, and that have more /// than one use, this map indicates what regularized operand to use. This /// allows us to avoid legalizing the same thing more than once. std::map LegalizedNodes; /// PromotedNodes - For nodes that are below legal width, and that have more /// than one use, this map indicates what promoted value to use. This allows /// us to avoid promoting the same thing more than once. std::map PromotedNodes; /// ExpandedNodes - For nodes that need to be expanded, and which have more /// than one use, this map indicates which which operands are the expanded /// version of the input. This allows us to avoid expanding the same node /// more than once. std::map > ExpandedNodes; void AddLegalizedOperand(SDOperand From, SDOperand To) { bool isNew = LegalizedNodes.insert(std::make_pair(From, To)).second; assert(isNew && "Got into the map somehow?"); } void AddPromotedOperand(SDOperand From, SDOperand To) { bool isNew = PromotedNodes.insert(std::make_pair(From, To)).second; assert(isNew && "Got into the map somehow?"); } /// setValueTypeAction - Set the action for a particular value type. This /// assumes an action has not already been set for this value type. void setValueTypeAction(MVT::ValueType VT, LegalizeAction A) { ValueTypeActions |= A << (VT*2); if (A == Promote) { MVT::ValueType PromoteTo; if (VT == MVT::f32) PromoteTo = MVT::f64; else { unsigned LargerReg = VT+1; while (!TLI.hasNativeSupportFor((MVT::ValueType)LargerReg)) { ++LargerReg; assert(MVT::isInteger((MVT::ValueType)LargerReg) && "Nothing to promote to??"); } PromoteTo = (MVT::ValueType)LargerReg; } assert(MVT::isInteger(VT) == MVT::isInteger(PromoteTo) && MVT::isFloatingPoint(VT) == MVT::isFloatingPoint(PromoteTo) && "Can only promote from int->int or fp->fp!"); assert(VT < PromoteTo && "Must promote to a larger type!"); TransformToType[VT] = PromoteTo; } else if (A == Expand) { assert(MVT::isInteger(VT) && VT > MVT::i8 && "Cannot expand this type: target must support SOME integer reg!"); // Expand to the next smaller integer type! TransformToType[VT] = (MVT::ValueType)(VT-1); } } public: SelectionDAGLegalize(TargetLowering &TLI, SelectionDAG &DAG); /// Run - While there is still lowering to do, perform a pass over the DAG. /// Most regularization can be done in a single pass, but targets that require /// large values to be split into registers multiple times (e.g. i64 -> 4x /// i16) require iteration for these values (the first iteration will demote /// to i32, the second will demote to i16). void Run() { do { NeedsAnotherIteration = false; LegalizeDAG(); } while (NeedsAnotherIteration); } /// getTypeAction - Return how we should legalize values of this type, either /// it is already legal or we need to expand it into multiple registers of /// smaller integer type, or we need to promote it to a larger type. LegalizeAction getTypeAction(MVT::ValueType VT) const { return (LegalizeAction)((ValueTypeActions >> (2*VT)) & 3); } /// isTypeLegal - Return true if this type is legal on this target. /// bool isTypeLegal(MVT::ValueType VT) const { return getTypeAction(VT) == Legal; } private: void LegalizeDAG(); SDOperand LegalizeOp(SDOperand O); void ExpandOp(SDOperand O, SDOperand &Lo, SDOperand &Hi); SDOperand PromoteOp(SDOperand O); SDOperand getIntPtrConstant(uint64_t Val) { return DAG.getConstant(Val, TLI.getPointerTy()); } }; } SelectionDAGLegalize::SelectionDAGLegalize(TargetLowering &tli, SelectionDAG &dag) : TLI(tli), DAG(dag), ValueTypeActions(0) { assert(MVT::LAST_VALUETYPE <= 16 && "Too many value types for ValueTypeActions to hold!"); // Inspect all of the ValueType's possible, deciding how to process them. for (unsigned IntReg = MVT::i1; IntReg <= MVT::i128; ++IntReg) // If TLI says we are expanding this type, expand it! if (TLI.getNumElements((MVT::ValueType)IntReg) != 1) setValueTypeAction((MVT::ValueType)IntReg, Expand); else if (!TLI.hasNativeSupportFor((MVT::ValueType)IntReg)) // Otherwise, if we don't have native support, we must promote to a // larger type. setValueTypeAction((MVT::ValueType)IntReg, Promote); // If the target does not have native support for F32, promote it to F64. if (!TLI.hasNativeSupportFor(MVT::f32)) setValueTypeAction(MVT::f32, Promote); } void SelectionDAGLegalize::LegalizeDAG() { SDOperand OldRoot = DAG.getRoot(); SDOperand NewRoot = LegalizeOp(OldRoot); DAG.setRoot(NewRoot); ExpandedNodes.clear(); LegalizedNodes.clear(); // Remove dead nodes now. DAG.RemoveDeadNodes(OldRoot.Val); } SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) { assert(getTypeAction(Op.getValueType()) == Legal && "Caller should expand or promote operands that are not legal!"); // If this operation defines any values that cannot be represented in a // register on this target, make sure to expand or promote them. if (Op.Val->getNumValues() > 1) { for (unsigned i = 0, e = Op.Val->getNumValues(); i != e; ++i) switch (getTypeAction(Op.Val->getValueType(i))) { case Legal: break; // Nothing to do. case Expand: { SDOperand T1, T2; ExpandOp(Op.getValue(i), T1, T2); assert(LegalizedNodes.count(Op) && "Expansion didn't add legal operands!"); return LegalizedNodes[Op]; } case Promote: PromoteOp(Op.getValue(i)); assert(LegalizedNodes.count(Op) && "Expansion didn't add legal operands!"); return LegalizedNodes[Op]; } } std::map::iterator I = LegalizedNodes.find(Op); if (I != LegalizedNodes.end()) return I->second; SDOperand Tmp1, Tmp2, Tmp3; SDOperand Result = Op; SDNode *Node = Op.Val; switch (Node->getOpcode()) { default: std::cerr << "NODE: "; Node->dump(); std::cerr << "\n"; assert(0 && "Do not know how to legalize this operator!"); abort(); case ISD::EntryToken: case ISD::FrameIndex: case ISD::GlobalAddress: case ISD::ExternalSymbol: case ISD::ConstantPool: // Nothing to do. assert(getTypeAction(Node->getValueType(0)) == Legal && "This must be legal!"); break; case ISD::CopyFromReg: Tmp1 = LegalizeOp(Node->getOperand(0)); if (Tmp1 != Node->getOperand(0)) Result = DAG.getCopyFromReg(cast(Node)->getReg(), Node->getValueType(0), Tmp1); break; case ISD::ImplicitDef: Tmp1 = LegalizeOp(Node->getOperand(0)); if (Tmp1 != Node->getOperand(0)) Result = DAG.getImplicitDef(Tmp1, cast(Node)->getReg()); break; case ISD::Constant: // We know we don't need to expand constants here, constants only have one // value and we check that it is fine above. // FIXME: Maybe we should handle things like targets that don't support full // 32-bit immediates? break; case ISD::ConstantFP: { // Spill FP immediates to the constant pool if the target cannot directly // codegen them. Targets often have some immediate values that can be // efficiently generated into an FP register without a load. We explicitly // leave these constants as ConstantFP nodes for the target to deal with. ConstantFPSDNode *CFP = cast(Node); // Check to see if this FP immediate is already legal. bool isLegal = false; for (TargetLowering::legal_fpimm_iterator I = TLI.legal_fpimm_begin(), E = TLI.legal_fpimm_end(); I != E; ++I) if (CFP->isExactlyValue(*I)) { isLegal = true; break; } if (!isLegal) { // Otherwise we need to spill the constant to memory. MachineConstantPool *CP = DAG.getMachineFunction().getConstantPool(); bool Extend = false; // If a FP immediate is precise when represented as a float, we put it // into the constant pool as a float, even if it's is statically typed // as a double. MVT::ValueType VT = CFP->getValueType(0); bool isDouble = VT == MVT::f64; ConstantFP *LLVMC = ConstantFP::get(isDouble ? Type::DoubleTy : Type::FloatTy, CFP->getValue()); if (isDouble && CFP->isExactlyValue((float)CFP->getValue())) { LLVMC = cast(ConstantExpr::getCast(LLVMC, Type::FloatTy)); VT = MVT::f32; Extend = true; } SDOperand CPIdx = DAG.getConstantPool(CP->getConstantPoolIndex(LLVMC), TLI.getPointerTy()); Result = DAG.getLoad(VT, DAG.getEntryNode(), CPIdx); if (Extend) Result = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Result); } break; } case ISD::TokenFactor: { std::vector Ops; bool Changed = false; for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) { Ops.push_back(LegalizeOp(Node->getOperand(i))); // Legalize the operands Changed |= Ops[i] != Node->getOperand(i); } if (Changed) Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Ops); break; } case ISD::ADJCALLSTACKDOWN: case ISD::ADJCALLSTACKUP: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. // There is no need to legalize the size argument (Operand #1) if (Tmp1 != Node->getOperand(0)) Result = DAG.getNode(Node->getOpcode(), MVT::Other, Tmp1, Node->getOperand(1)); break; case ISD::DYNAMIC_STACKALLOC: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the size. Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the alignment. if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || Tmp3 != Node->getOperand(2)) Result = DAG.getNode(ISD::DYNAMIC_STACKALLOC, Node->getValueType(0), Tmp1, Tmp2, Tmp3); else Result = Op.getValue(0); // Since this op produces two values, make sure to remember that we // legalized both of them. AddLegalizedOperand(SDOperand(Node, 0), Result); AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1)); return Result.getValue(Op.ResNo); case ISD::CALL: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the callee. if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) { std::vector RetTyVTs; RetTyVTs.reserve(Node->getNumValues()); for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i) RetTyVTs.push_back(Node->getValueType(i)); Result = SDOperand(DAG.getCall(RetTyVTs, Tmp1, Tmp2), 0); } else { Result = Result.getValue(0); } // Since calls produce multiple values, make sure to remember that we // legalized all of them. for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i) AddLegalizedOperand(SDOperand(Node, i), Result.getValue(i)); return Result.getValue(Op.ResNo); case ISD::BR: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. if (Tmp1 != Node->getOperand(0)) Result = DAG.getNode(ISD::BR, MVT::Other, Tmp1, Node->getOperand(1)); break; case ISD::BRCOND: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. // FIXME: booleans might not be legal! Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the condition. // Basic block destination (Op#2) is always legal. if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getNode(ISD::BRCOND, MVT::Other, Tmp1, Tmp2, Node->getOperand(2)); break; case ISD::LOAD: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getLoad(Node->getValueType(0), Tmp1, Tmp2); else Result = SDOperand(Node, 0); // Since loads produce two values, make sure to remember that we legalized // both of them. AddLegalizedOperand(SDOperand(Node, 0), Result); AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1)); return Result.getValue(Op.ResNo); case ISD::EXTLOAD: case ISD::SEXTLOAD: case ISD::ZEXTLOAD: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1, Tmp2, cast(Node)->getExtraValueType()); else Result = SDOperand(Node, 0); // Since loads produce two values, make sure to remember that we legalized // both of them. AddLegalizedOperand(SDOperand(Node, 0), Result); AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1)); return Result.getValue(Op.ResNo); case ISD::EXTRACT_ELEMENT: // Get both the low and high parts. ExpandOp(Node->getOperand(0), Tmp1, Tmp2); if (cast(Node->getOperand(1))->getValue()) Result = Tmp2; // 1 -> Hi else Result = Tmp1; // 0 -> Lo break; case ISD::CopyToReg: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. switch (getTypeAction(Node->getOperand(1).getValueType())) { case Legal: // Legalize the incoming value (must be legal). Tmp2 = LegalizeOp(Node->getOperand(1)); if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getCopyToReg(Tmp1, Tmp2, cast(Node)->getReg()); break; case Expand: { SDOperand Lo, Hi; ExpandOp(Node->getOperand(1), Lo, Hi); unsigned Reg = cast(Node)->getReg(); Result = DAG.getCopyToReg(Tmp1, Lo, Reg); Result = DAG.getCopyToReg(Result, Hi, Reg+1); assert(isTypeLegal(Result.getValueType()) && "Cannot expand multiple times yet (i64 -> i16)"); break; } case Promote: assert(0 && "Don't know what it means to promote this!"); abort(); } break; case ISD::RET: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. switch (Node->getNumOperands()) { case 2: // ret val switch (getTypeAction(Node->getOperand(1).getValueType())) { case Legal: Tmp2 = LegalizeOp(Node->getOperand(1)); if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Tmp2); break; case Expand: { SDOperand Lo, Hi; ExpandOp(Node->getOperand(1), Lo, Hi); Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Lo, Hi); break; } case Promote: assert(0 && "Can't promote return value!"); } break; case 1: // ret void if (Tmp1 != Node->getOperand(0)) Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1); break; default: { // ret std::vector NewValues; NewValues.push_back(Tmp1); for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i) switch (getTypeAction(Node->getOperand(i).getValueType())) { case Legal: NewValues.push_back(LegalizeOp(Node->getOperand(i))); break; case Expand: { SDOperand Lo, Hi; ExpandOp(Node->getOperand(i), Lo, Hi); NewValues.push_back(Lo); NewValues.push_back(Hi); break; } case Promote: assert(0 && "Can't promote return value!"); } Result = DAG.getNode(ISD::RET, MVT::Other, NewValues); break; } } break; case ISD::STORE: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp2 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer. // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' if (ConstantFPSDNode *CFP =dyn_cast(Node->getOperand(1))){ if (CFP->getValueType(0) == MVT::f32) { union { unsigned I; float F; } V; V.F = CFP->getValue(); Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, DAG.getConstant(V.I, MVT::i32), Tmp2); } else { assert(CFP->getValueType(0) == MVT::f64 && "Unknown FP type!"); union { uint64_t I; double F; } V; V.F = CFP->getValue(); Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, DAG.getConstant(V.I, MVT::i64), Tmp2); } Op = Result; Node = Op.Val; } switch (getTypeAction(Node->getOperand(1).getValueType())) { case Legal: { SDOperand Val = LegalizeOp(Node->getOperand(1)); if (Val != Node->getOperand(1) || Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(2)) Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Val, Tmp2); break; } case Promote: // Truncate the value and store the result. Tmp3 = PromoteOp(Node->getOperand(1)); Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp3, Tmp2, Node->getOperand(1).getValueType()); break; case Expand: SDOperand Lo, Hi; ExpandOp(Node->getOperand(1), Lo, Hi); if (!TLI.isLittleEndian()) std::swap(Lo, Hi); // FIXME: These two stores are independent of each other! Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Lo, Tmp2); unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8; Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2, getIntPtrConstant(IncrementSize)); assert(isTypeLegal(Tmp2.getValueType()) && "Pointers must be legal!"); Result = DAG.getNode(ISD::STORE, MVT::Other, Result, Hi, Tmp2); } break; case ISD::TRUNCSTORE: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer. switch (getTypeAction(Node->getOperand(1).getValueType())) { case Legal: Tmp2 = LegalizeOp(Node->getOperand(1)); if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || Tmp3 != Node->getOperand(2)) Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp2, Tmp3, cast(Node)->getExtraValueType()); break; case Promote: case Expand: assert(0 && "Cannot handle illegal TRUNCSTORE yet!"); } break; case ISD::SELECT: // FIXME: BOOLS MAY REQUIRE PROMOTION! Tmp1 = LegalizeOp(Node->getOperand(0)); // Cond Tmp2 = LegalizeOp(Node->getOperand(1)); // TrueVal Tmp3 = LegalizeOp(Node->getOperand(2)); // FalseVal if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || Tmp3 != Node->getOperand(2)) Result = DAG.getNode(ISD::SELECT, Node->getValueType(0), Tmp1, Tmp2,Tmp3); break; case ISD::SETCC: switch (getTypeAction(Node->getOperand(0).getValueType())) { case Legal: Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getSetCC(cast(Node)->getCondition(), Tmp1, Tmp2); break; case Promote: assert(0 && "Can't promote setcc operands yet!"); break; case Expand: SDOperand LHSLo, LHSHi, RHSLo, RHSHi; ExpandOp(Node->getOperand(0), LHSLo, LHSHi); ExpandOp(Node->getOperand(1), RHSLo, RHSHi); switch (cast(Node)->getCondition()) { case ISD::SETEQ: case ISD::SETNE: Tmp1 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSLo, RHSLo); Tmp2 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSHi, RHSHi); Tmp1 = DAG.getNode(ISD::OR, Tmp1.getValueType(), Tmp1, Tmp2); Result = DAG.getSetCC(cast(Node)->getCondition(), Tmp1, DAG.getConstant(0, Tmp1.getValueType())); break; default: // FIXME: This generated code sucks. ISD::CondCode LowCC; switch (cast(Node)->getCondition()) { default: assert(0 && "Unknown integer setcc!"); case ISD::SETLT: case ISD::SETULT: LowCC = ISD::SETULT; break; case ISD::SETGT: case ISD::SETUGT: LowCC = ISD::SETUGT; break; case ISD::SETLE: case ISD::SETULE: LowCC = ISD::SETULE; break; case ISD::SETGE: case ISD::SETUGE: LowCC = ISD::SETUGE; break; } // Tmp1 = lo(op1) < lo(op2) // Always unsigned comparison // Tmp2 = hi(op1) < hi(op2) // Signedness depends on operands // dest = hi(op1) == hi(op2) ? Tmp1 : Tmp2; // NOTE: on targets without efficient SELECT of bools, we can always use // this identity: (B1 ? B2 : B3) --> (B1 & B2)|(!B1&B3) Tmp1 = DAG.getSetCC(LowCC, LHSLo, RHSLo); Tmp2 = DAG.getSetCC(cast(Node)->getCondition(), LHSHi, RHSHi); Result = DAG.getSetCC(ISD::SETEQ, LHSHi, RHSHi); Result = DAG.getNode(ISD::SELECT, MVT::i1, Result, Tmp1, Tmp2); break; } } break; case ISD::MEMSET: case ISD::MEMCPY: case ISD::MEMMOVE: { Tmp1 = LegalizeOp(Node->getOperand(0)); Tmp2 = LegalizeOp(Node->getOperand(1)); Tmp3 = LegalizeOp(Node->getOperand(2)); SDOperand Tmp4 = LegalizeOp(Node->getOperand(3)); SDOperand Tmp5 = LegalizeOp(Node->getOperand(4)); if (TLI.isOperationSupported(Node->getOpcode(), MVT::Other)) { if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || Tmp3 != Node->getOperand(2) || Tmp4 != Node->getOperand(3) || Tmp5 != Node->getOperand(4)) { std::vector Ops; Ops.push_back(Tmp1); Ops.push_back(Tmp2); Ops.push_back(Tmp3); Ops.push_back(Tmp4); Ops.push_back(Tmp5); Result = DAG.getNode(Node->getOpcode(), MVT::Other, Ops); } } else { // Otherwise, the target does not support this operation. Lower the // operation to an explicit libcall as appropriate. MVT::ValueType IntPtr = TLI.getPointerTy(); const Type *IntPtrTy = TLI.getTargetData().getIntPtrType(); std::vector > Args; const char *FnName = 0; if (Node->getOpcode() == ISD::MEMSET) { Args.push_back(std::make_pair(Tmp2, IntPtrTy)); // Extend the ubyte argument to be an int value for the call. Tmp3 = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Tmp3); Args.push_back(std::make_pair(Tmp3, Type::IntTy)); Args.push_back(std::make_pair(Tmp4, IntPtrTy)); FnName = "memset"; } else if (Node->getOpcode() == ISD::MEMCPY || Node->getOpcode() == ISD::MEMMOVE) { Args.push_back(std::make_pair(Tmp2, IntPtrTy)); Args.push_back(std::make_pair(Tmp3, IntPtrTy)); Args.push_back(std::make_pair(Tmp4, IntPtrTy)); FnName = Node->getOpcode() == ISD::MEMMOVE ? "memmove" : "memcpy"; } else { assert(0 && "Unknown op!"); } std::pair CallResult = TLI.LowerCallTo(Tmp1, Type::VoidTy, DAG.getExternalSymbol(FnName, IntPtr), Args, DAG); Result = LegalizeOp(CallResult.second); } break; } case ISD::ADD: case ISD::SUB: case ISD::MUL: case ISD::UDIV: case ISD::SDIV: case ISD::UREM: case ISD::SREM: case ISD::AND: case ISD::OR: case ISD::XOR: case ISD::SHL: case ISD::SRL: case ISD::SRA: Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,Tmp2); break; case ISD::ZERO_EXTEND: case ISD::SIGN_EXTEND: case ISD::TRUNCATE: case ISD::FP_EXTEND: case ISD::FP_ROUND: case ISD::FP_TO_SINT: case ISD::FP_TO_UINT: case ISD::SINT_TO_FP: case ISD::UINT_TO_FP: switch (getTypeAction(Node->getOperand(0).getValueType())) { case Legal: Tmp1 = LegalizeOp(Node->getOperand(0)); if (Tmp1 != Node->getOperand(0)) Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1); break; case Expand: assert(Node->getOpcode() != ISD::SINT_TO_FP && Node->getOpcode() != ISD::UINT_TO_FP && "Cannot lower Xint_to_fp to a call yet!"); // In the expand case, we must be dealing with a truncate, because // otherwise the result would be larger than the source. assert(Node->getOpcode() == ISD::TRUNCATE && "Shouldn't need to expand other operators here!"); ExpandOp(Node->getOperand(0), Tmp1, Tmp2); // Since the result is legal, we should just be able to truncate the low // part of the source. Result = DAG.getNode(ISD::TRUNCATE, Node->getValueType(0), Tmp1); break; case Promote: switch (Node->getOpcode()) { case ISD::ZERO_EXTEND: { // Mask out the high bits. uint64_t MaskCst = 1ULL << (MVT::getSizeInBits(Node->getOperand(0).getValueType()))-1; Tmp1 = PromoteOp(Node->getOperand(0)); Result = DAG.getNode(ISD::AND, Node->getValueType(0), Tmp1, DAG.getConstant(MaskCst, Node->getValueType(0))); break; } case ISD::SIGN_EXTEND: case ISD::TRUNCATE: case ISD::FP_EXTEND: case ISD::FP_ROUND: case ISD::FP_TO_SINT: case ISD::FP_TO_UINT: case ISD::SINT_TO_FP: case ISD::UINT_TO_FP: Node->dump(); assert(0 && "Do not know how to promote this yet!"); } } break; case ISD::FP_ROUND_INREG: case ISD::SIGN_EXTEND_INREG: case ISD::ZERO_EXTEND_INREG: { Tmp1 = LegalizeOp(Node->getOperand(0)); MVT::ValueType ExtraVT = cast(Node)->getExtraValueType(); // If this operation is not supported, convert it to a shl/shr or load/store // pair. if (!TLI.isOperationSupported(Node->getOpcode(), ExtraVT)) { // If this is an integer extend and shifts are supported, do that. if (Node->getOpcode() == ISD::ZERO_EXTEND_INREG) { // NOTE: we could fall back on load/store here too for targets without // AND. However, it is doubtful that any exist. // AND out the appropriate bits. SDOperand Mask = DAG.getConstant((1ULL << MVT::getSizeInBits(ExtraVT))-1, Node->getValueType(0)); Result = DAG.getNode(ISD::AND, Node->getValueType(0), Node->getOperand(0), Mask); } else if (Node->getOpcode() == ISD::SIGN_EXTEND_INREG) { // NOTE: we could fall back on load/store here too for targets without // SAR. However, it is doubtful that any exist. unsigned BitsDiff = MVT::getSizeInBits(Node->getValueType(0)) - MVT::getSizeInBits(ExtraVT); SDOperand ShiftCst = DAG.getConstant(BitsDiff, MVT::i8); Result = DAG.getNode(ISD::SHL, Node->getValueType(0), Node->getOperand(0), ShiftCst); Result = DAG.getNode(ISD::SRA, Node->getValueType(0), Result, ShiftCst); } else if (Node->getOpcode() == ISD::FP_ROUND_INREG) { // The only way we can lower this is to turn it into a STORETRUNC, // EXTLOAD pair, targetting a temporary location (a stack slot). // NOTE: there is a choice here between constantly creating new stack // slots and always reusing the same one. We currently always create // new ones, as reuse may inhibit scheduling. const Type *Ty = MVT::getTypeForValueType(ExtraVT); unsigned TySize = (unsigned)TLI.getTargetData().getTypeSize(Ty); unsigned Align = TLI.getTargetData().getTypeAlignment(Ty); MachineFunction &MF = DAG.getMachineFunction(); int SSFI = MF.getFrameInfo()->CreateStackObject((unsigned)TySize, Align); SDOperand StackSlot = DAG.getFrameIndex(SSFI, TLI.getPointerTy()); Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, DAG.getEntryNode(), Node->getOperand(0), StackSlot, ExtraVT); Result = DAG.getNode(ISD::EXTLOAD, Node->getValueType(0), Result, StackSlot, ExtraVT); } else { assert(0 && "Unknown op"); } Result = LegalizeOp(Result); } else { if (Tmp1 != Node->getOperand(0)) Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1, ExtraVT); } break; } } if (!Op.Val->hasOneUse()) AddLegalizedOperand(Op, Result); return Result; } SDOperand SelectionDAGLegalize::PromoteOp(SDOperand Op) { MVT::ValueType VT = Op.getValueType(); MVT::ValueType NVT = TransformToType[VT]; assert(getTypeAction(VT) == Promote && "Caller should expand or legalize operands that are not promotable!"); assert(NVT > VT && MVT::isInteger(NVT) == MVT::isInteger(VT) && "Cannot promote to smaller type!"); std::map::iterator I = PromotedNodes.find(Op); if (I != PromotedNodes.end()) return I->second; SDOperand Tmp1, Tmp2, Tmp3; SDOperand Result; SDNode *Node = Op.Val; // Promotion needs an optimization step to clean up after it, and is not // careful to avoid operations the target does not support. Make sure that // all generated operations are legalized in the next iteration. NeedsAnotherIteration = true; switch (Node->getOpcode()) { default: std::cerr << "NODE: "; Node->dump(); std::cerr << "\n"; assert(0 && "Do not know how to promote this operator!"); abort(); case ISD::Constant: Result = DAG.getNode(ISD::ZERO_EXTEND, NVT, Op); assert(isa(Result) && "Didn't constant fold zext?"); break; case ISD::ConstantFP: Result = DAG.getNode(ISD::FP_EXTEND, NVT, Op); assert(isa(Result) && "Didn't constant fold fp_extend?"); break; case ISD::TRUNCATE: switch (getTypeAction(Node->getOperand(0).getValueType())) { case Legal: Result = LegalizeOp(Node->getOperand(0)); assert(Result.getValueType() >= NVT && "This truncation doesn't make sense!"); if (Result.getValueType() > NVT) // Truncate to NVT instead of VT Result = DAG.getNode(ISD::TRUNCATE, NVT, Result); break; case Expand: assert(0 && "Cannot handle expand yet"); case Promote: assert(0 && "Cannot handle promote-promote yet"); } break; case ISD::AND: case ISD::OR: case ISD::XOR: // The logical ops can just execute, they don't care what the top bits // coming in are. Tmp1 = PromoteOp(Node->getOperand(0)); Tmp2 = PromoteOp(Node->getOperand(1)); assert(Tmp1.getValueType() == NVT && Tmp2.getValueType() == NVT); Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2); break; case ISD::ADD: case ISD::MUL: // The input may have strange things in the top bits of the registers, but // these operations don't care. They may have wierd bits going out, but // that too is okay if they are integer operations. Tmp1 = PromoteOp(Node->getOperand(0)); Tmp2 = PromoteOp(Node->getOperand(1)); assert(Tmp1.getValueType() == NVT && Tmp2.getValueType() == NVT); Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2); // However, if this is a floating point operation, they will give excess // precision that we may not be able to tolerate. If we DO allow excess // precision, just leave it, otherwise excise it. if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision) Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT); break; case ISD::LOAD: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. Result = DAG.getNode(ISD::EXTLOAD, NVT, Tmp1, Tmp2, VT); // Remember that we legalized the chain. AddLegalizedOperand(Op.getValue(1), Result.getValue(1)); break; case ISD::SELECT: Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the condition Tmp2 = PromoteOp(Node->getOperand(1)); // Legalize the op0 Tmp3 = PromoteOp(Node->getOperand(2)); // Legalize the op1 Result = DAG.getNode(ISD::SELECT, NVT, Tmp1, Tmp2, Tmp3); break; } assert(Result.Val && "Didn't set a result!"); AddPromotedOperand(Op, Result); return Result; } /// ExpandOp - Expand the specified SDOperand into its two component pieces /// Lo&Hi. Note that the Op MUST be an expanded type. As a result of this, the /// LegalizeNodes map is filled in for any results that are not expanded, the /// ExpandedNodes map is filled in for any results that are expanded, and the /// Lo/Hi values are returned. void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){ MVT::ValueType VT = Op.getValueType(); MVT::ValueType NVT = TransformToType[VT]; SDNode *Node = Op.Val; assert(getTypeAction(VT) == Expand && "Not an expanded type!"); assert(MVT::isInteger(VT) && "Cannot expand FP values!"); assert(MVT::isInteger(NVT) && NVT < VT && "Cannot expand to FP value or to larger int value!"); // If there is more than one use of this, see if we already expanded it. // There is no use remembering values that only have a single use, as the map // entries will never be reused. if (!Node->hasOneUse()) { std::map >::iterator I = ExpandedNodes.find(Op); if (I != ExpandedNodes.end()) { Lo = I->second.first; Hi = I->second.second; return; } } // Expanding to multiple registers needs to perform an optimization step, and // is not careful to avoid operations the target does not support. Make sure // that all generated operations are legalized in the next iteration. NeedsAnotherIteration = true; const char *LibCallName = 0; switch (Node->getOpcode()) { default: std::cerr << "NODE: "; Node->dump(); std::cerr << "\n"; assert(0 && "Do not know how to expand this operator!"); abort(); case ISD::Constant: { uint64_t Cst = cast(Node)->getValue(); Lo = DAG.getConstant(Cst, NVT); Hi = DAG.getConstant(Cst >> MVT::getSizeInBits(NVT), NVT); break; } case ISD::CopyFromReg: { unsigned Reg = cast(Node)->getReg(); // Aggregate register values are always in consequtive pairs. Lo = DAG.getCopyFromReg(Reg, NVT, Node->getOperand(0)); Hi = DAG.getCopyFromReg(Reg+1, NVT, Lo.getValue(1)); // Remember that we legalized the chain. AddLegalizedOperand(Op.getValue(1), Hi.getValue(1)); assert(isTypeLegal(NVT) && "Cannot expand this multiple times yet!"); break; } case ISD::LOAD: { SDOperand Ch = LegalizeOp(Node->getOperand(0)); // Legalize the chain. SDOperand Ptr = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. Lo = DAG.getLoad(NVT, Ch, Ptr); // Increment the pointer to the other half. unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8; Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr, getIntPtrConstant(IncrementSize)); // FIXME: This load is independent of the first one. Hi = DAG.getLoad(NVT, Lo.getValue(1), Ptr); // Remember that we legalized the chain. AddLegalizedOperand(Op.getValue(1), Hi.getValue(1)); if (!TLI.isLittleEndian()) std::swap(Lo, Hi); break; } case ISD::CALL: { SDOperand Chain = LegalizeOp(Node->getOperand(0)); // Legalize the chain. SDOperand Callee = LegalizeOp(Node->getOperand(1)); // Legalize the callee. assert(Node->getNumValues() == 2 && Op.ResNo == 0 && "Can only expand a call once so far, not i64 -> i16!"); std::vector RetTyVTs; RetTyVTs.reserve(3); RetTyVTs.push_back(NVT); RetTyVTs.push_back(NVT); RetTyVTs.push_back(MVT::Other); SDNode *NC = DAG.getCall(RetTyVTs, Chain, Callee); Lo = SDOperand(NC, 0); Hi = SDOperand(NC, 1); // Insert the new chain mapping. AddLegalizedOperand(Op.getValue(1), Hi.getValue(2)); break; } case ISD::AND: case ISD::OR: case ISD::XOR: { // Simple logical operators -> two trivial pieces. SDOperand LL, LH, RL, RH; ExpandOp(Node->getOperand(0), LL, LH); ExpandOp(Node->getOperand(1), RL, RH); Lo = DAG.getNode(Node->getOpcode(), NVT, LL, RL); Hi = DAG.getNode(Node->getOpcode(), NVT, LH, RH); break; } case ISD::SELECT: { SDOperand C, LL, LH, RL, RH; // FIXME: BOOLS MAY REQUIRE PROMOTION! C = LegalizeOp(Node->getOperand(0)); ExpandOp(Node->getOperand(1), LL, LH); ExpandOp(Node->getOperand(2), RL, RH); Lo = DAG.getNode(ISD::SELECT, NVT, C, LL, RL); Hi = DAG.getNode(ISD::SELECT, NVT, C, LH, RH); break; } case ISD::SIGN_EXTEND: { // The low part is just a sign extension of the input (which degenerates to // a copy). Lo = DAG.getNode(ISD::SIGN_EXTEND, NVT, LegalizeOp(Node->getOperand(0))); // The high part is obtained by SRA'ing all but one of the bits of the lo // part. unsigned LoSize = MVT::getSizeInBits(Lo.getValueType()); Hi = DAG.getNode(ISD::SRA, NVT, Lo, DAG.getConstant(LoSize-1, MVT::i8)); break; } case ISD::ZERO_EXTEND: // The low part is just a zero extension of the input (which degenerates to // a copy). Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, LegalizeOp(Node->getOperand(0))); // The high part is just a zero. Hi = DAG.getConstant(0, NVT); break; // These operators cannot be expanded directly, emit them as calls to // library functions. case ISD::FP_TO_SINT: if (Node->getOperand(0).getValueType() == MVT::f32) LibCallName = "__fixsfdi"; else LibCallName = "__fixdfdi"; break; case ISD::FP_TO_UINT: if (Node->getOperand(0).getValueType() == MVT::f32) LibCallName = "__fixunssfdi"; else LibCallName = "__fixunsdfdi"; break; case ISD::ADD: LibCallName = "__adddi3"; break; case ISD::SUB: LibCallName = "__subdi3"; break; case ISD::MUL: LibCallName = "__muldi3"; break; case ISD::SDIV: LibCallName = "__divdi3"; break; case ISD::UDIV: LibCallName = "__udivdi3"; break; case ISD::SREM: LibCallName = "__moddi3"; break; case ISD::UREM: LibCallName = "__umoddi3"; break; case ISD::SHL: LibCallName = "__ashldi3"; break; case ISD::SRA: LibCallName = "__ashrdi3"; break; case ISD::SRL: LibCallName = "__lshrdi3"; break; } // Int2FP -> __floatdisf/__floatdidf // If this is to be expanded into a libcall... do so now. if (LibCallName) { TargetLowering::ArgListTy Args; for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) Args.push_back(std::make_pair(Node->getOperand(i), MVT::getTypeForValueType(Node->getOperand(i).getValueType()))); SDOperand Callee = DAG.getExternalSymbol(LibCallName, TLI.getPointerTy()); // We don't care about token chains for libcalls. We just use the entry // node as our input and ignore the output chain. This allows us to place // calls wherever we need them to satisfy data dependences. SDOperand Result = TLI.LowerCallTo(DAG.getEntryNode(), MVT::getTypeForValueType(Op.getValueType()), Callee, Args, DAG).first; ExpandOp(Result, Lo, Hi); } // Remember in a map if the values will be reused later. if (!Node->hasOneUse()) { bool isNew = ExpandedNodes.insert(std::make_pair(Op, std::make_pair(Lo, Hi))).second; assert(isNew && "Value already expanded?!?"); } } // SelectionDAG::Legalize - This is the entry point for the file. // void SelectionDAG::Legalize(TargetLowering &TLI) { /// run - This is the main entry point to this class. /// SelectionDAGLegalize(TLI, *this).Run(); }