X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FSelectionDAG%2FTargetLowering.cpp;h=79e8013e4f585e3fc1c349f6e788a3b07e2a6abc;hb=d97321ceb313f06fd9a824cf26b9dc5b80b3eb9d;hp=c4ccbf5ef05992b3ab027c02da552eb359ed06d6;hpb=8e6be8b9218b3b9c44b784b559d49236f80c1049;p=oota-llvm.git diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp index c4ccbf5ef05..79e8013e4f5 100644 --- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -12,24 +12,49 @@ //===----------------------------------------------------------------------===// #include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetData.h" #include "llvm/Target/TargetMachine.h" +#include "llvm/Target/MRegisterInfo.h" +#include "llvm/DerivedTypes.h" #include "llvm/CodeGen/SelectionDAG.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/Support/MathExtras.h" using namespace llvm; TargetLowering::TargetLowering(TargetMachine &tm) - : TM(tm), TD(TM.getTargetData()), ValueTypeActions(0) { - assert(ISD::BUILTIN_OP_END <= 128 && + : TM(tm), TD(TM.getTargetData()) { + assert(ISD::BUILTIN_OP_END <= 156 && "Fixed size array in TargetLowering is not large enough!"); // All operations default to being supported. memset(OpActions, 0, sizeof(OpActions)); + memset(LoadXActions, 0, sizeof(LoadXActions)); + memset(&StoreXActions, 0, sizeof(StoreXActions)); + // Initialize all indexed load / store to expand. + for (unsigned VT = 0; VT != (unsigned)MVT::LAST_VALUETYPE; ++VT) { + for (unsigned IM = (unsigned)ISD::PRE_INC; + IM != (unsigned)ISD::LAST_INDEXED_MODE; ++IM) { + setIndexedLoadAction(IM, (MVT::ValueType)VT, Expand); + setIndexedStoreAction(IM, (MVT::ValueType)VT, Expand); + } + } - IsLittleEndian = TD.isLittleEndian(); - ShiftAmountTy = SetCCResultTy = PointerTy = getValueType(TD.getIntPtrType()); + IsLittleEndian = TD->isLittleEndian(); + UsesGlobalOffsetTable = false; + ShiftAmountTy = SetCCResultTy = PointerTy = getValueType(TD->getIntPtrType()); ShiftAmtHandling = Undefined; memset(RegClassForVT, 0,MVT::LAST_VALUETYPE*sizeof(TargetRegisterClass*)); - maxStoresPerMemSet = maxStoresPerMemCpy = maxStoresPerMemMove = 8; + memset(TargetDAGCombineArray, 0, + sizeof(TargetDAGCombineArray)/sizeof(TargetDAGCombineArray[0])); + maxStoresPerMemset = maxStoresPerMemcpy = maxStoresPerMemmove = 8; allowUnalignedMemoryAccesses = false; - UseUnderscoreSetJmpLongJmp = false; + UseUnderscoreSetJmp = false; + UseUnderscoreLongJmp = false; + IntDivIsCheap = false; + Pow2DivIsCheap = false; + StackPointerRegisterToSaveRestore = 0; + SchedPreferenceInfo = SchedulingForLatency; + JumpBufSize = 0; + JumpBufAlignment = 0; } TargetLowering::~TargetLowering() {} @@ -40,8 +65,8 @@ static void SetValueTypeAction(MVT::ValueType VT, TargetLowering::LegalizeAction Action, TargetLowering &TLI, MVT::ValueType *TransformToType, - unsigned &ValueTypeActions) { - ValueTypeActions |= Action << (VT*2); + TargetLowering::ValueTypeActionImpl &ValueTypeActions) { + ValueTypeActions.setTypeAction(VT, Action); if (Action == TargetLowering::Promote) { MVT::ValueType PromoteTo; if (VT == MVT::f32) @@ -62,10 +87,17 @@ static void SetValueTypeAction(MVT::ValueType VT, assert(VT < PromoteTo && "Must promote to a larger type!"); TransformToType[VT] = PromoteTo; } else if (Action == TargetLowering::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); + // f32 and f64 is each expanded to corresponding integer type of same size. + if (VT == MVT::f32) + TransformToType[VT] = MVT::i32; + else if (VT == MVT::f64) + TransformToType[VT] = MVT::i64; + else { + assert((VT == MVT::Vector || 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); + } } } @@ -73,7 +105,7 @@ static void SetValueTypeAction(MVT::ValueType VT, /// computeRegisterProperties - Once all of the register classes are added, /// this allows us to compute derived properties we expose. void TargetLowering::computeRegisterProperties() { - assert(MVT::LAST_VALUETYPE <= 16 && + assert(MVT::LAST_VALUETYPE <= 32 && "Too many value types for ValueTypeActions to hold!"); // Everything defaults to one. @@ -105,14 +137,1530 @@ void TargetLowering::computeRegisterProperties() { else TransformToType[(MVT::ValueType)IntReg] = (MVT::ValueType)IntReg; - // If the target does not have native support for F32, promote it to F64. - if (!isTypeLegal(MVT::f32)) - SetValueTypeAction(MVT::f32, Promote, *this, - TransformToType, ValueTypeActions); - else + // If the target does not have native F64 support, expand it to I64. We will + // be generating soft float library calls. If the target does not have native + // support for F32, promote it to F64 if it is legal. Otherwise, expand it to + // I32. + if (isTypeLegal(MVT::f64)) + TransformToType[MVT::f64] = MVT::f64; + else { + NumElementsForVT[MVT::f64] = NumElementsForVT[MVT::i64]; + SetValueTypeAction(MVT::f64, Expand, *this, TransformToType, + ValueTypeActions); + } + if (isTypeLegal(MVT::f32)) TransformToType[MVT::f32] = MVT::f32; + else if (isTypeLegal(MVT::f64)) + SetValueTypeAction(MVT::f32, Promote, *this, TransformToType, + ValueTypeActions); + else { + NumElementsForVT[MVT::f32] = NumElementsForVT[MVT::i32]; + SetValueTypeAction(MVT::f32, Expand, *this, TransformToType, + ValueTypeActions); + } + + // Set MVT::Vector to always be Expanded + SetValueTypeAction(MVT::Vector, Expand, *this, TransformToType, + ValueTypeActions); + + // Loop over all of the legal vector value types, specifying an identity type + // transformation. + for (unsigned i = MVT::FIRST_VECTOR_VALUETYPE; + i <= MVT::LAST_VECTOR_VALUETYPE; ++i) { + if (isTypeLegal((MVT::ValueType)i)) + TransformToType[i] = (MVT::ValueType)i; + } +} + +const char *TargetLowering::getTargetNodeName(unsigned Opcode) const { + return NULL; +} + +/// getPackedTypeBreakdown - Packed types are broken down into some number of +/// legal first class types. For example, <8 x float> maps to 2 MVT::v4f32 +/// with Altivec or SSE1, or 8 promoted MVT::f64 values with the X86 FP stack. +/// +/// This method returns the number and type of the resultant breakdown. +/// +unsigned TargetLowering::getPackedTypeBreakdown(const PackedType *PTy, + MVT::ValueType &PTyElementVT, + MVT::ValueType &PTyLegalElementVT) const { + // Figure out the right, legal destination reg to copy into. + unsigned NumElts = PTy->getNumElements(); + MVT::ValueType EltTy = getValueType(PTy->getElementType()); + + unsigned NumVectorRegs = 1; + + // Divide the input until we get to a supported size. This will always + // end with a scalar if the target doesn't support vectors. + while (NumElts > 1 && !isTypeLegal(getVectorType(EltTy, NumElts))) { + NumElts >>= 1; + NumVectorRegs <<= 1; + } + + MVT::ValueType VT; + if (NumElts == 1) { + VT = EltTy; + } else { + VT = getVectorType(EltTy, NumElts); + } + PTyElementVT = VT; + + MVT::ValueType DestVT = getTypeToTransformTo(VT); + PTyLegalElementVT = DestVT; + if (DestVT < VT) { + // Value is expanded, e.g. i64 -> i16. + return NumVectorRegs*(MVT::getSizeInBits(VT)/MVT::getSizeInBits(DestVT)); + } else { + // Otherwise, promotion or legal types use the same number of registers as + // the vector decimated to the appropriate level. + return NumVectorRegs; + } + + return 1; +} + +//===----------------------------------------------------------------------===// +// Optimization Methods +//===----------------------------------------------------------------------===// + +/// ShrinkDemandedConstant - Check to see if the specified operand of the +/// specified instruction is a constant integer. If so, check to see if there +/// are any bits set in the constant that are not demanded. If so, shrink the +/// constant and return true. +bool TargetLowering::TargetLoweringOpt::ShrinkDemandedConstant(SDOperand Op, + uint64_t Demanded) { + // FIXME: ISD::SELECT, ISD::SELECT_CC + switch(Op.getOpcode()) { + default: break; + case ISD::AND: + case ISD::OR: + case ISD::XOR: + if (ConstantSDNode *C = dyn_cast(Op.getOperand(1))) + if ((~Demanded & C->getValue()) != 0) { + MVT::ValueType VT = Op.getValueType(); + SDOperand New = DAG.getNode(Op.getOpcode(), VT, Op.getOperand(0), + DAG.getConstant(Demanded & C->getValue(), + VT)); + return CombineTo(Op, New); + } + break; + } + return false; +} + +/// SimplifyDemandedBits - Look at Op. At this point, we know that only the +/// DemandedMask bits of the result of Op are ever used downstream. If we can +/// use this information to simplify Op, create a new simplified DAG node and +/// return true, returning the original and new nodes in Old and New. Otherwise, +/// analyze the expression and return a mask of KnownOne and KnownZero bits for +/// the expression (used to simplify the caller). The KnownZero/One bits may +/// only be accurate for those bits in the DemandedMask. +bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask, + uint64_t &KnownZero, + uint64_t &KnownOne, + TargetLoweringOpt &TLO, + unsigned Depth) const { + KnownZero = KnownOne = 0; // Don't know anything. + // Other users may use these bits. + if (!Op.Val->hasOneUse()) { + if (Depth != 0) { + // If not at the root, Just compute the KnownZero/KnownOne bits to + // simplify things downstream. + ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth); + return false; + } + // If this is the root being simplified, allow it to have multiple uses, + // just set the DemandedMask to all bits. + DemandedMask = MVT::getIntVTBitMask(Op.getValueType()); + } else if (DemandedMask == 0) { + // Not demanding any bits from Op. + if (Op.getOpcode() != ISD::UNDEF) + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::UNDEF, Op.getValueType())); + return false; + } else if (Depth == 6) { // Limit search depth. + return false; + } + + uint64_t KnownZero2, KnownOne2, KnownZeroOut, KnownOneOut; + switch (Op.getOpcode()) { + case ISD::Constant: + // We know all of the bits for a constant! + KnownOne = cast(Op)->getValue() & DemandedMask; + KnownZero = ~KnownOne & DemandedMask; + return false; // Don't fall through, will infinitely loop. + case ISD::AND: + // If the RHS is a constant, check to see if the LHS would be zero without + // using the bits from the RHS. Below, we use knowledge about the RHS to + // simplify the LHS, here we're using information from the LHS to simplify + // the RHS. + if (ConstantSDNode *RHSC = dyn_cast(Op.getOperand(1))) { + uint64_t LHSZero, LHSOne; + ComputeMaskedBits(Op.getOperand(0), DemandedMask, + LHSZero, LHSOne, Depth+1); + // If the LHS already has zeros where RHSC does, this and is dead. + if ((LHSZero & DemandedMask) == (~RHSC->getValue() & DemandedMask)) + return TLO.CombineTo(Op, Op.getOperand(0)); + // If any of the set bits in the RHS are known zero on the LHS, shrink + // the constant. + if (TLO.ShrinkDemandedConstant(Op, ~LHSZero & DemandedMask)) + return true; + } + + if (SimplifyDemandedBits(Op.getOperand(1), DemandedMask, KnownZero, + KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask & ~KnownZero, + KnownZero2, KnownOne2, TLO, Depth+1)) + return true; + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // If all of the demanded bits are known one on one side, return the other. + // These bits cannot contribute to the result of the 'and'. + if ((DemandedMask & ~KnownZero2 & KnownOne)==(DemandedMask & ~KnownZero2)) + return TLO.CombineTo(Op, Op.getOperand(0)); + if ((DemandedMask & ~KnownZero & KnownOne2)==(DemandedMask & ~KnownZero)) + return TLO.CombineTo(Op, Op.getOperand(1)); + // If all of the demanded bits in the inputs are known zeros, return zero. + if ((DemandedMask & (KnownZero|KnownZero2)) == DemandedMask) + return TLO.CombineTo(Op, TLO.DAG.getConstant(0, Op.getValueType())); + // If the RHS is a constant, see if we can simplify it. + if (TLO.ShrinkDemandedConstant(Op, DemandedMask & ~KnownZero2)) + return true; + + // Output known-1 bits are only known if set in both the LHS & RHS. + KnownOne &= KnownOne2; + // Output known-0 are known to be clear if zero in either the LHS | RHS. + KnownZero |= KnownZero2; + break; + case ISD::OR: + if (SimplifyDemandedBits(Op.getOperand(1), DemandedMask, KnownZero, + KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask & ~KnownOne, + KnownZero2, KnownOne2, TLO, Depth+1)) + return true; + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // If all of the demanded bits are known zero on one side, return the other. + // These bits cannot contribute to the result of the 'or'. + if ((DemandedMask & ~KnownOne2 & KnownZero) == (DemandedMask & ~KnownOne2)) + return TLO.CombineTo(Op, Op.getOperand(0)); + if ((DemandedMask & ~KnownOne & KnownZero2) == (DemandedMask & ~KnownOne)) + return TLO.CombineTo(Op, Op.getOperand(1)); + // If all of the potentially set bits on one side are known to be set on + // the other side, just use the 'other' side. + if ((DemandedMask & (~KnownZero) & KnownOne2) == + (DemandedMask & (~KnownZero))) + return TLO.CombineTo(Op, Op.getOperand(0)); + if ((DemandedMask & (~KnownZero2) & KnownOne) == + (DemandedMask & (~KnownZero2))) + return TLO.CombineTo(Op, Op.getOperand(1)); + // If the RHS is a constant, see if we can simplify it. + if (TLO.ShrinkDemandedConstant(Op, DemandedMask)) + return true; + + // Output known-0 bits are only known if clear in both the LHS & RHS. + KnownZero &= KnownZero2; + // Output known-1 are known to be set if set in either the LHS | RHS. + KnownOne |= KnownOne2; + break; + case ISD::XOR: + if (SimplifyDemandedBits(Op.getOperand(1), DemandedMask, KnownZero, + KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask, KnownZero2, + KnownOne2, TLO, Depth+1)) + return true; + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // If all of the demanded bits are known zero on one side, return the other. + // These bits cannot contribute to the result of the 'xor'. + if ((DemandedMask & KnownZero) == DemandedMask) + return TLO.CombineTo(Op, Op.getOperand(0)); + if ((DemandedMask & KnownZero2) == DemandedMask) + return TLO.CombineTo(Op, Op.getOperand(1)); + + // If all of the unknown bits are known to be zero on one side or the other + // (but not both) turn this into an *inclusive* or. + // e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0 + if ((DemandedMask & ~KnownZero & ~KnownZero2) == 0) + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::OR, Op.getValueType(), + Op.getOperand(0), + Op.getOperand(1))); + + // Output known-0 bits are known if clear or set in both the LHS & RHS. + KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2); + // Output known-1 are known to be set if set in only one of the LHS, RHS. + KnownOneOut = (KnownZero & KnownOne2) | (KnownOne & KnownZero2); + + // If all of the demanded bits on one side are known, and all of the set + // bits on that side are also known to be set on the other side, turn this + // into an AND, as we know the bits will be cleared. + // e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2 + if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask) { // all known + if ((KnownOne & KnownOne2) == KnownOne) { + MVT::ValueType VT = Op.getValueType(); + SDOperand ANDC = TLO.DAG.getConstant(~KnownOne & DemandedMask, VT); + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::AND, VT, Op.getOperand(0), + ANDC)); + } + } + + // If the RHS is a constant, see if we can simplify it. + // FIXME: for XOR, we prefer to force bits to 1 if they will make a -1. + if (TLO.ShrinkDemandedConstant(Op, DemandedMask)) + return true; + + KnownZero = KnownZeroOut; + KnownOne = KnownOneOut; + break; + case ISD::SETCC: + // If we know the result of a setcc has the top bits zero, use this info. + if (getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) + KnownZero |= (MVT::getIntVTBitMask(Op.getValueType()) ^ 1ULL); + break; + case ISD::SELECT: + if (SimplifyDemandedBits(Op.getOperand(2), DemandedMask, KnownZero, + KnownOne, TLO, Depth+1)) + return true; + if (SimplifyDemandedBits(Op.getOperand(1), DemandedMask, KnownZero2, + KnownOne2, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // If the operands are constants, see if we can simplify them. + if (TLO.ShrinkDemandedConstant(Op, DemandedMask)) + return true; + + // Only known if known in both the LHS and RHS. + KnownOne &= KnownOne2; + KnownZero &= KnownZero2; + break; + case ISD::SELECT_CC: + if (SimplifyDemandedBits(Op.getOperand(3), DemandedMask, KnownZero, + KnownOne, TLO, Depth+1)) + return true; + if (SimplifyDemandedBits(Op.getOperand(2), DemandedMask, KnownZero2, + KnownOne2, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // If the operands are constants, see if we can simplify them. + if (TLO.ShrinkDemandedConstant(Op, DemandedMask)) + return true; + + // Only known if known in both the LHS and RHS. + KnownOne &= KnownOne2; + KnownZero &= KnownZero2; + break; + case ISD::SHL: + if (ConstantSDNode *SA = dyn_cast(Op.getOperand(1))) { + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask >> SA->getValue(), + KnownZero, KnownOne, TLO, Depth+1)) + return true; + KnownZero <<= SA->getValue(); + KnownOne <<= SA->getValue(); + KnownZero |= (1ULL << SA->getValue())-1; // low bits known zero. + } + break; + case ISD::SRL: + if (ConstantSDNode *SA = dyn_cast(Op.getOperand(1))) { + MVT::ValueType VT = Op.getValueType(); + unsigned ShAmt = SA->getValue(); + + // Compute the new bits that are at the top now. + uint64_t TypeMask = MVT::getIntVTBitMask(VT); + if (SimplifyDemandedBits(Op.getOperand(0), + (DemandedMask << ShAmt) & TypeMask, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero &= TypeMask; + KnownOne &= TypeMask; + KnownZero >>= ShAmt; + KnownOne >>= ShAmt; + + uint64_t HighBits = (1ULL << ShAmt)-1; + HighBits <<= MVT::getSizeInBits(VT) - ShAmt; + KnownZero |= HighBits; // High bits known zero. + } + break; + case ISD::SRA: + if (ConstantSDNode *SA = dyn_cast(Op.getOperand(1))) { + MVT::ValueType VT = Op.getValueType(); + unsigned ShAmt = SA->getValue(); + + // Compute the new bits that are at the top now. + uint64_t TypeMask = MVT::getIntVTBitMask(VT); + + uint64_t InDemandedMask = (DemandedMask << ShAmt) & TypeMask; + + // If any of the demanded bits are produced by the sign extension, we also + // demand the input sign bit. + uint64_t HighBits = (1ULL << ShAmt)-1; + HighBits <<= MVT::getSizeInBits(VT) - ShAmt; + if (HighBits & DemandedMask) + InDemandedMask |= MVT::getIntVTSignBit(VT); + + if (SimplifyDemandedBits(Op.getOperand(0), InDemandedMask, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero &= TypeMask; + KnownOne &= TypeMask; + KnownZero >>= ShAmt; + KnownOne >>= ShAmt; + + // Handle the sign bits. + uint64_t SignBit = MVT::getIntVTSignBit(VT); + SignBit >>= ShAmt; // Adjust to where it is now in the mask. + + // If the input sign bit is known to be zero, or if none of the top bits + // are demanded, turn this into an unsigned shift right. + if ((KnownZero & SignBit) || (HighBits & ~DemandedMask) == HighBits) { + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, VT, Op.getOperand(0), + Op.getOperand(1))); + } else if (KnownOne & SignBit) { // New bits are known one. + KnownOne |= HighBits; + } + } + break; + case ISD::SIGN_EXTEND_INREG: { + MVT::ValueType EVT = cast(Op.getOperand(1))->getVT(); + + // Sign extension. Compute the demanded bits in the result that are not + // present in the input. + uint64_t NewBits = ~MVT::getIntVTBitMask(EVT) & DemandedMask; + + // If none of the extended bits are demanded, eliminate the sextinreg. + if (NewBits == 0) + return TLO.CombineTo(Op, Op.getOperand(0)); + + uint64_t InSignBit = MVT::getIntVTSignBit(EVT); + int64_t InputDemandedBits = DemandedMask & MVT::getIntVTBitMask(EVT); + + // Since the sign extended bits are demanded, we know that the sign + // bit is demanded. + InputDemandedBits |= InSignBit; + + if (SimplifyDemandedBits(Op.getOperand(0), InputDemandedBits, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + + // If the sign bit of the input is known set or clear, then we know the + // top bits of the result. + + // If the input sign bit is known zero, convert this into a zero extension. + if (KnownZero & InSignBit) + return TLO.CombineTo(Op, + TLO.DAG.getZeroExtendInReg(Op.getOperand(0), EVT)); + + if (KnownOne & InSignBit) { // Input sign bit known set + KnownOne |= NewBits; + KnownZero &= ~NewBits; + } else { // Input sign bit unknown + KnownZero &= ~NewBits; + KnownOne &= ~NewBits; + } + break; + } + case ISD::CTTZ: + case ISD::CTLZ: + case ISD::CTPOP: { + MVT::ValueType VT = Op.getValueType(); + unsigned LowBits = Log2_32(MVT::getSizeInBits(VT))+1; + KnownZero = ~((1ULL << LowBits)-1) & MVT::getIntVTBitMask(VT); + KnownOne = 0; + break; + } + case ISD::LOAD: { + if (ISD::isZEXTLoad(Op.Val)) { + LoadSDNode *LD = cast(Op); + MVT::ValueType VT = LD->getLoadedVT(); + KnownZero |= ~MVT::getIntVTBitMask(VT) & DemandedMask; + } + break; + } + case ISD::ZERO_EXTEND: { + uint64_t InMask = MVT::getIntVTBitMask(Op.getOperand(0).getValueType()); + + // If none of the top bits are demanded, convert this into an any_extend. + uint64_t NewBits = (~InMask) & DemandedMask; + if (NewBits == 0) + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ANY_EXTEND, + Op.getValueType(), + Op.getOperand(0))); + + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask & InMask, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero |= NewBits; + break; + } + case ISD::SIGN_EXTEND: { + MVT::ValueType InVT = Op.getOperand(0).getValueType(); + uint64_t InMask = MVT::getIntVTBitMask(InVT); + uint64_t InSignBit = MVT::getIntVTSignBit(InVT); + uint64_t NewBits = (~InMask) & DemandedMask; + + // If none of the top bits are demanded, convert this into an any_extend. + if (NewBits == 0) + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ANY_EXTEND,Op.getValueType(), + Op.getOperand(0))); + + // Since some of the sign extended bits are demanded, we know that the sign + // bit is demanded. + uint64_t InDemandedBits = DemandedMask & InMask; + InDemandedBits |= InSignBit; + + if (SimplifyDemandedBits(Op.getOperand(0), InDemandedBits, KnownZero, + KnownOne, TLO, Depth+1)) + return true; + + // If the sign bit is known zero, convert this to a zero extend. + if (KnownZero & InSignBit) + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ZERO_EXTEND, + Op.getValueType(), + Op.getOperand(0))); + + // If the sign bit is known one, the top bits match. + if (KnownOne & InSignBit) { + KnownOne |= NewBits; + KnownZero &= ~NewBits; + } else { // Otherwise, top bits aren't known. + KnownOne &= ~NewBits; + KnownZero &= ~NewBits; + } + break; + } + case ISD::ANY_EXTEND: { + uint64_t InMask = MVT::getIntVTBitMask(Op.getOperand(0).getValueType()); + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask & InMask, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + break; + } + case ISD::TRUNCATE: { + // Simplify the input, using demanded bit information, and compute the known + // zero/one bits live out. + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + + // If the input is only used by this truncate, see if we can shrink it based + // on the known demanded bits. + if (Op.getOperand(0).Val->hasOneUse()) { + SDOperand In = Op.getOperand(0); + switch (In.getOpcode()) { + default: break; + case ISD::SRL: + // Shrink SRL by a constant if none of the high bits shifted in are + // demanded. + if (ConstantSDNode *ShAmt = dyn_cast(In.getOperand(1))){ + uint64_t HighBits = MVT::getIntVTBitMask(In.getValueType()); + HighBits &= ~MVT::getIntVTBitMask(Op.getValueType()); + HighBits >>= ShAmt->getValue(); + + if (ShAmt->getValue() < MVT::getSizeInBits(Op.getValueType()) && + (DemandedMask & HighBits) == 0) { + // None of the shifted in bits are needed. Add a truncate of the + // shift input, then shift it. + SDOperand NewTrunc = TLO.DAG.getNode(ISD::TRUNCATE, + Op.getValueType(), + In.getOperand(0)); + return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL,Op.getValueType(), + NewTrunc, In.getOperand(1))); + } + } + break; + } + } + + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + uint64_t OutMask = MVT::getIntVTBitMask(Op.getValueType()); + KnownZero &= OutMask; + KnownOne &= OutMask; + break; + } + case ISD::AssertZext: { + MVT::ValueType VT = cast(Op.getOperand(1))->getVT(); + uint64_t InMask = MVT::getIntVTBitMask(VT); + if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask & InMask, + KnownZero, KnownOne, TLO, Depth+1)) + return true; + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero |= ~InMask & DemandedMask; + break; + } + case ISD::ADD: + case ISD::SUB: + case ISD::INTRINSIC_WO_CHAIN: + case ISD::INTRINSIC_W_CHAIN: + case ISD::INTRINSIC_VOID: + // Just use ComputeMaskedBits to compute output bits. + ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth); + break; + } + + // If we know the value of all of the demanded bits, return this as a + // constant. + if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask) + return TLO.CombineTo(Op, TLO.DAG.getConstant(KnownOne, Op.getValueType())); + + return false; +} - assert(isTypeLegal(MVT::f64) && "Target does not support FP?"); - TransformToType[MVT::f64] = MVT::f64; +/// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero. We use +/// this predicate to simplify operations downstream. Mask is known to be zero +/// for bits that V cannot have. +bool TargetLowering::MaskedValueIsZero(SDOperand Op, uint64_t Mask, + unsigned Depth) const { + uint64_t KnownZero, KnownOne; + ComputeMaskedBits(Op, Mask, KnownZero, KnownOne, Depth); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + return (KnownZero & Mask) == Mask; +} + +/// ComputeMaskedBits - Determine which of the bits specified in Mask are +/// known to be either zero or one and return them in the KnownZero/KnownOne +/// bitsets. This code only analyzes bits in Mask, in order to short-circuit +/// processing. +void TargetLowering::ComputeMaskedBits(SDOperand Op, uint64_t Mask, + uint64_t &KnownZero, uint64_t &KnownOne, + unsigned Depth) const { + KnownZero = KnownOne = 0; // Don't know anything. + if (Depth == 6 || Mask == 0) + return; // Limit search depth. + + uint64_t KnownZero2, KnownOne2; + + switch (Op.getOpcode()) { + case ISD::Constant: + // We know all of the bits for a constant! + KnownOne = cast(Op)->getValue() & Mask; + KnownZero = ~KnownOne & Mask; + return; + case ISD::AND: + // If either the LHS or the RHS are Zero, the result is zero. + ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1); + Mask &= ~KnownZero; + ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero2, KnownOne2, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // Output known-1 bits are only known if set in both the LHS & RHS. + KnownOne &= KnownOne2; + // Output known-0 are known to be clear if zero in either the LHS | RHS. + KnownZero |= KnownZero2; + return; + case ISD::OR: + ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1); + Mask &= ~KnownOne; + ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero2, KnownOne2, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // Output known-0 bits are only known if clear in both the LHS & RHS. + KnownZero &= KnownZero2; + // Output known-1 are known to be set if set in either the LHS | RHS. + KnownOne |= KnownOne2; + return; + case ISD::XOR: { + ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1); + ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero2, KnownOne2, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // Output known-0 bits are known if clear or set in both the LHS & RHS. + uint64_t KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2); + // Output known-1 are known to be set if set in only one of the LHS, RHS. + KnownOne = (KnownZero & KnownOne2) | (KnownOne & KnownZero2); + KnownZero = KnownZeroOut; + return; + } + case ISD::SELECT: + ComputeMaskedBits(Op.getOperand(2), Mask, KnownZero, KnownOne, Depth+1); + ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero2, KnownOne2, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // Only known if known in both the LHS and RHS. + KnownOne &= KnownOne2; + KnownZero &= KnownZero2; + return; + case ISD::SELECT_CC: + ComputeMaskedBits(Op.getOperand(3), Mask, KnownZero, KnownOne, Depth+1); + ComputeMaskedBits(Op.getOperand(2), Mask, KnownZero2, KnownOne2, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // Only known if known in both the LHS and RHS. + KnownOne &= KnownOne2; + KnownZero &= KnownZero2; + return; + case ISD::SETCC: + // If we know the result of a setcc has the top bits zero, use this info. + if (getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) + KnownZero |= (MVT::getIntVTBitMask(Op.getValueType()) ^ 1ULL); + return; + case ISD::SHL: + // (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0 + if (ConstantSDNode *SA = dyn_cast(Op.getOperand(1))) { + ComputeMaskedBits(Op.getOperand(0), Mask >> SA->getValue(), + KnownZero, KnownOne, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero <<= SA->getValue(); + KnownOne <<= SA->getValue(); + KnownZero |= (1ULL << SA->getValue())-1; // low bits known zero. + } + return; + case ISD::SRL: + // (ushr X, C1) & C2 == 0 iff (-1 >> C1) & C2 == 0 + if (ConstantSDNode *SA = dyn_cast(Op.getOperand(1))) { + MVT::ValueType VT = Op.getValueType(); + unsigned ShAmt = SA->getValue(); + + uint64_t TypeMask = MVT::getIntVTBitMask(VT); + ComputeMaskedBits(Op.getOperand(0), (Mask << ShAmt) & TypeMask, + KnownZero, KnownOne, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero &= TypeMask; + KnownOne &= TypeMask; + KnownZero >>= ShAmt; + KnownOne >>= ShAmt; + + uint64_t HighBits = (1ULL << ShAmt)-1; + HighBits <<= MVT::getSizeInBits(VT)-ShAmt; + KnownZero |= HighBits; // High bits known zero. + } + return; + case ISD::SRA: + if (ConstantSDNode *SA = dyn_cast(Op.getOperand(1))) { + MVT::ValueType VT = Op.getValueType(); + unsigned ShAmt = SA->getValue(); + + // Compute the new bits that are at the top now. + uint64_t TypeMask = MVT::getIntVTBitMask(VT); + + uint64_t InDemandedMask = (Mask << ShAmt) & TypeMask; + // If any of the demanded bits are produced by the sign extension, we also + // demand the input sign bit. + uint64_t HighBits = (1ULL << ShAmt)-1; + HighBits <<= MVT::getSizeInBits(VT) - ShAmt; + if (HighBits & Mask) + InDemandedMask |= MVT::getIntVTSignBit(VT); + + ComputeMaskedBits(Op.getOperand(0), InDemandedMask, KnownZero, KnownOne, + Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero &= TypeMask; + KnownOne &= TypeMask; + KnownZero >>= ShAmt; + KnownOne >>= ShAmt; + + // Handle the sign bits. + uint64_t SignBit = MVT::getIntVTSignBit(VT); + SignBit >>= ShAmt; // Adjust to where it is now in the mask. + + if (KnownZero & SignBit) { + KnownZero |= HighBits; // New bits are known zero. + } else if (KnownOne & SignBit) { + KnownOne |= HighBits; // New bits are known one. + } + } + return; + case ISD::SIGN_EXTEND_INREG: { + MVT::ValueType EVT = cast(Op.getOperand(1))->getVT(); + + // Sign extension. Compute the demanded bits in the result that are not + // present in the input. + uint64_t NewBits = ~MVT::getIntVTBitMask(EVT) & Mask; + + uint64_t InSignBit = MVT::getIntVTSignBit(EVT); + int64_t InputDemandedBits = Mask & MVT::getIntVTBitMask(EVT); + + // If the sign extended bits are demanded, we know that the sign + // bit is demanded. + if (NewBits) + InputDemandedBits |= InSignBit; + + ComputeMaskedBits(Op.getOperand(0), InputDemandedBits, + KnownZero, KnownOne, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + + // If the sign bit of the input is known set or clear, then we know the + // top bits of the result. + if (KnownZero & InSignBit) { // Input sign bit known clear + KnownZero |= NewBits; + KnownOne &= ~NewBits; + } else if (KnownOne & InSignBit) { // Input sign bit known set + KnownOne |= NewBits; + KnownZero &= ~NewBits; + } else { // Input sign bit unknown + KnownZero &= ~NewBits; + KnownOne &= ~NewBits; + } + return; + } + case ISD::CTTZ: + case ISD::CTLZ: + case ISD::CTPOP: { + MVT::ValueType VT = Op.getValueType(); + unsigned LowBits = Log2_32(MVT::getSizeInBits(VT))+1; + KnownZero = ~((1ULL << LowBits)-1) & MVT::getIntVTBitMask(VT); + KnownOne = 0; + return; + } + case ISD::LOAD: { + if (ISD::isZEXTLoad(Op.Val)) { + LoadSDNode *LD = cast(Op); + MVT::ValueType VT = LD->getLoadedVT(); + KnownZero |= ~MVT::getIntVTBitMask(VT) & Mask; + } + return; + } + case ISD::ZERO_EXTEND: { + uint64_t InMask = MVT::getIntVTBitMask(Op.getOperand(0).getValueType()); + uint64_t NewBits = (~InMask) & Mask; + ComputeMaskedBits(Op.getOperand(0), Mask & InMask, KnownZero, + KnownOne, Depth+1); + KnownZero |= NewBits & Mask; + KnownOne &= ~NewBits; + return; + } + case ISD::SIGN_EXTEND: { + MVT::ValueType InVT = Op.getOperand(0).getValueType(); + unsigned InBits = MVT::getSizeInBits(InVT); + uint64_t InMask = MVT::getIntVTBitMask(InVT); + uint64_t InSignBit = 1ULL << (InBits-1); + uint64_t NewBits = (~InMask) & Mask; + uint64_t InDemandedBits = Mask & InMask; + + // If any of the sign extended bits are demanded, we know that the sign + // bit is demanded. + if (NewBits & Mask) + InDemandedBits |= InSignBit; + + ComputeMaskedBits(Op.getOperand(0), InDemandedBits, KnownZero, + KnownOne, Depth+1); + // If the sign bit is known zero or one, the top bits match. + if (KnownZero & InSignBit) { + KnownZero |= NewBits; + KnownOne &= ~NewBits; + } else if (KnownOne & InSignBit) { + KnownOne |= NewBits; + KnownZero &= ~NewBits; + } else { // Otherwise, top bits aren't known. + KnownOne &= ~NewBits; + KnownZero &= ~NewBits; + } + return; + } + case ISD::ANY_EXTEND: { + MVT::ValueType VT = Op.getOperand(0).getValueType(); + ComputeMaskedBits(Op.getOperand(0), Mask & MVT::getIntVTBitMask(VT), + KnownZero, KnownOne, Depth+1); + return; + } + case ISD::TRUNCATE: { + ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero, KnownOne, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + uint64_t OutMask = MVT::getIntVTBitMask(Op.getValueType()); + KnownZero &= OutMask; + KnownOne &= OutMask; + break; + } + case ISD::AssertZext: { + MVT::ValueType VT = cast(Op.getOperand(1))->getVT(); + uint64_t InMask = MVT::getIntVTBitMask(VT); + ComputeMaskedBits(Op.getOperand(0), Mask & InMask, KnownZero, + KnownOne, Depth+1); + KnownZero |= (~InMask) & Mask; + return; + } + case ISD::ADD: { + // If either the LHS or the RHS are Zero, the result is zero. + ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1); + ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero2, KnownOne2, Depth+1); + assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); + + // Output known-0 bits are known if clear or set in both the low clear bits + // common to both LHS & RHS. For example, 8+(X<<3) is known to have the + // low 3 bits clear. + uint64_t KnownZeroOut = std::min(CountTrailingZeros_64(~KnownZero), + CountTrailingZeros_64(~KnownZero2)); + + KnownZero = (1ULL << KnownZeroOut) - 1; + KnownOne = 0; + return; + } + case ISD::SUB: { + ConstantSDNode *CLHS = dyn_cast(Op.getOperand(0)); + if (!CLHS) return; + + // We know that the top bits of C-X are clear if X contains less bits + // than C (i.e. no wrap-around can happen). For example, 20-X is + // positive if we can prove that X is >= 0 and < 16. + MVT::ValueType VT = CLHS->getValueType(0); + if ((CLHS->getValue() & MVT::getIntVTSignBit(VT)) == 0) { // sign bit clear + unsigned NLZ = CountLeadingZeros_64(CLHS->getValue()+1); + uint64_t MaskV = (1ULL << (63-NLZ))-1; // NLZ can't be 64 with no sign bit + MaskV = ~MaskV & MVT::getIntVTBitMask(VT); + ComputeMaskedBits(Op.getOperand(1), MaskV, KnownZero, KnownOne, Depth+1); + + // If all of the MaskV bits are known to be zero, then we know the output + // top bits are zero, because we now know that the output is from [0-C]. + if ((KnownZero & MaskV) == MaskV) { + unsigned NLZ2 = CountLeadingZeros_64(CLHS->getValue()); + KnownZero = ~((1ULL << (64-NLZ2))-1) & Mask; // Top bits known zero. + KnownOne = 0; // No one bits known. + } else { + KnownZero = KnownOne = 0; // Otherwise, nothing known. + } + } + return; + } + default: + // Allow the target to implement this method for its nodes. + if (Op.getOpcode() >= ISD::BUILTIN_OP_END) { + case ISD::INTRINSIC_WO_CHAIN: + case ISD::INTRINSIC_W_CHAIN: + case ISD::INTRINSIC_VOID: + computeMaskedBitsForTargetNode(Op, Mask, KnownZero, KnownOne); + } + return; + } } +/// computeMaskedBitsForTargetNode - Determine which of the bits specified +/// in Mask are known to be either zero or one and return them in the +/// KnownZero/KnownOne bitsets. +void TargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op, + uint64_t Mask, + uint64_t &KnownZero, + uint64_t &KnownOne, + unsigned Depth) const { + assert((Op.getOpcode() >= ISD::BUILTIN_OP_END || + Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN || + Op.getOpcode() == ISD::INTRINSIC_W_CHAIN || + Op.getOpcode() == ISD::INTRINSIC_VOID) && + "Should use MaskedValueIsZero if you don't know whether Op" + " is a target node!"); + KnownZero = 0; + KnownOne = 0; +} + +/// ComputeNumSignBits - Return the number of times the sign bit of the +/// register is replicated into the other bits. We know that at least 1 bit +/// is always equal to the sign bit (itself), but other cases can give us +/// information. For example, immediately after an "SRA X, 2", we know that +/// the top 3 bits are all equal to each other, so we return 3. +unsigned TargetLowering::ComputeNumSignBits(SDOperand Op, unsigned Depth) const{ + MVT::ValueType VT = Op.getValueType(); + assert(MVT::isInteger(VT) && "Invalid VT!"); + unsigned VTBits = MVT::getSizeInBits(VT); + unsigned Tmp, Tmp2; + + if (Depth == 6) + return 1; // Limit search depth. + + switch (Op.getOpcode()) { + default: break; + case ISD::AssertSext: + Tmp = MVT::getSizeInBits(cast(Op.getOperand(1))->getVT()); + return VTBits-Tmp+1; + case ISD::AssertZext: + Tmp = MVT::getSizeInBits(cast(Op.getOperand(1))->getVT()); + return VTBits-Tmp; + + case ISD::Constant: { + uint64_t Val = cast(Op)->getValue(); + // If negative, invert the bits, then look at it. + if (Val & MVT::getIntVTSignBit(VT)) + Val = ~Val; + + // Shift the bits so they are the leading bits in the int64_t. + Val <<= 64-VTBits; + + // Return # leading zeros. We use 'min' here in case Val was zero before + // shifting. We don't want to return '64' as for an i32 "0". + return std::min(VTBits, CountLeadingZeros_64(Val)); + } + + case ISD::SIGN_EXTEND: + Tmp = VTBits-MVT::getSizeInBits(Op.getOperand(0).getValueType()); + return ComputeNumSignBits(Op.getOperand(0), Depth+1) + Tmp; + + case ISD::SIGN_EXTEND_INREG: + // Max of the input and what this extends. + Tmp = MVT::getSizeInBits(cast(Op.getOperand(1))->getVT()); + Tmp = VTBits-Tmp+1; + + Tmp2 = ComputeNumSignBits(Op.getOperand(0), Depth+1); + return std::max(Tmp, Tmp2); + + case ISD::SRA: + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + // SRA X, C -> adds C sign bits. + if (ConstantSDNode *C = dyn_cast(Op.getOperand(1))) { + Tmp += C->getValue(); + if (Tmp > VTBits) Tmp = VTBits; + } + return Tmp; + case ISD::SHL: + if (ConstantSDNode *C = dyn_cast(Op.getOperand(1))) { + // shl destroys sign bits. + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + if (C->getValue() >= VTBits || // Bad shift. + C->getValue() >= Tmp) break; // Shifted all sign bits out. + return Tmp - C->getValue(); + } + break; + case ISD::AND: + case ISD::OR: + case ISD::XOR: // NOT is handled here. + // Logical binary ops preserve the number of sign bits. + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + if (Tmp == 1) return 1; // Early out. + Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1); + return std::min(Tmp, Tmp2); + + case ISD::SELECT: + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + if (Tmp == 1) return 1; // Early out. + Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1); + return std::min(Tmp, Tmp2); + + case ISD::SETCC: + // If setcc returns 0/-1, all bits are sign bits. + if (getSetCCResultContents() == ZeroOrNegativeOneSetCCResult) + return VTBits; + break; + case ISD::ROTL: + case ISD::ROTR: + if (ConstantSDNode *C = dyn_cast(Op.getOperand(1))) { + unsigned RotAmt = C->getValue() & (VTBits-1); + + // Handle rotate right by N like a rotate left by 32-N. + if (Op.getOpcode() == ISD::ROTR) + RotAmt = (VTBits-RotAmt) & (VTBits-1); + + // If we aren't rotating out all of the known-in sign bits, return the + // number that are left. This handles rotl(sext(x), 1) for example. + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + if (Tmp > RotAmt+1) return Tmp-RotAmt; + } + break; + case ISD::ADD: + // Add can have at most one carry bit. Thus we know that the output + // is, at worst, one more bit than the inputs. + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + if (Tmp == 1) return 1; // Early out. + + // Special case decrementing a value (ADD X, -1): + if (ConstantSDNode *CRHS = dyn_cast(Op.getOperand(0))) + if (CRHS->isAllOnesValue()) { + uint64_t KnownZero, KnownOne; + uint64_t Mask = MVT::getIntVTBitMask(VT); + ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero, KnownOne, Depth+1); + + // If the input is known to be 0 or 1, the output is 0/-1, which is all + // sign bits set. + if ((KnownZero|1) == Mask) + return VTBits; + + // If we are subtracting one from a positive number, there is no carry + // out of the result. + if (KnownZero & MVT::getIntVTSignBit(VT)) + return Tmp; + } + + Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1); + if (Tmp2 == 1) return 1; + return std::min(Tmp, Tmp2)-1; + break; + + case ISD::SUB: + Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1); + if (Tmp2 == 1) return 1; + + // Handle NEG. + if (ConstantSDNode *CLHS = dyn_cast(Op.getOperand(0))) + if (CLHS->getValue() == 0) { + uint64_t KnownZero, KnownOne; + uint64_t Mask = MVT::getIntVTBitMask(VT); + ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1); + // If the input is known to be 0 or 1, the output is 0/-1, which is all + // sign bits set. + if ((KnownZero|1) == Mask) + return VTBits; + + // If the input is known to be positive (the sign bit is known clear), + // the output of the NEG has the same number of sign bits as the input. + if (KnownZero & MVT::getIntVTSignBit(VT)) + return Tmp2; + + // Otherwise, we treat this like a SUB. + } + + // Sub can have at most one carry bit. Thus we know that the output + // is, at worst, one more bit than the inputs. + Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1); + if (Tmp == 1) return 1; // Early out. + return std::min(Tmp, Tmp2)-1; + break; + case ISD::TRUNCATE: + // FIXME: it's tricky to do anything useful for this, but it is an important + // case for targets like X86. + break; + } + + // Handle LOADX separately here. EXTLOAD case will fallthrough. + if (Op.getOpcode() == ISD::LOAD) { + LoadSDNode *LD = cast(Op); + unsigned ExtType = LD->getExtensionType(); + switch (ExtType) { + default: break; + case ISD::SEXTLOAD: // '17' bits known + Tmp = MVT::getSizeInBits(LD->getLoadedVT()); + return VTBits-Tmp+1; + case ISD::ZEXTLOAD: // '16' bits known + Tmp = MVT::getSizeInBits(LD->getLoadedVT()); + return VTBits-Tmp; + } + } + + // Allow the target to implement this method for its nodes. + if (Op.getOpcode() >= ISD::BUILTIN_OP_END || + Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN || + Op.getOpcode() == ISD::INTRINSIC_W_CHAIN || + Op.getOpcode() == ISD::INTRINSIC_VOID) { + unsigned NumBits = ComputeNumSignBitsForTargetNode(Op, Depth); + if (NumBits > 1) return NumBits; + } + + // Finally, if we can prove that the top bits of the result are 0's or 1's, + // use this information. + uint64_t KnownZero, KnownOne; + uint64_t Mask = MVT::getIntVTBitMask(VT); + ComputeMaskedBits(Op, Mask, KnownZero, KnownOne, Depth); + + uint64_t SignBit = MVT::getIntVTSignBit(VT); + if (KnownZero & SignBit) { // SignBit is 0 + Mask = KnownZero; + } else if (KnownOne & SignBit) { // SignBit is 1; + Mask = KnownOne; + } else { + // Nothing known. + return 1; + } + + // Okay, we know that the sign bit in Mask is set. Use CLZ to determine + // the number of identical bits in the top of the input value. + Mask ^= ~0ULL; + Mask <<= 64-VTBits; + // Return # leading zeros. We use 'min' here in case Val was zero before + // shifting. We don't want to return '64' as for an i32 "0". + return std::min(VTBits, CountLeadingZeros_64(Mask)); +} + + + +/// ComputeNumSignBitsForTargetNode - This method can be implemented by +/// targets that want to expose additional information about sign bits to the +/// DAG Combiner. +unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDOperand Op, + unsigned Depth) const { + assert((Op.getOpcode() >= ISD::BUILTIN_OP_END || + Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN || + Op.getOpcode() == ISD::INTRINSIC_W_CHAIN || + Op.getOpcode() == ISD::INTRINSIC_VOID) && + "Should use ComputeNumSignBits if you don't know whether Op" + " is a target node!"); + return 1; +} + + +SDOperand TargetLowering:: +PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const { + // Default implementation: no optimization. + return SDOperand(); +} + +//===----------------------------------------------------------------------===// +// Inline Assembler Implementation Methods +//===----------------------------------------------------------------------===// + +TargetLowering::ConstraintType +TargetLowering::getConstraintType(char ConstraintLetter) const { + // FIXME: lots more standard ones to handle. + switch (ConstraintLetter) { + default: return C_Unknown; + case 'r': return C_RegisterClass; + case 'm': // memory + case 'o': // offsetable + case 'V': // not offsetable + return C_Memory; + case 'i': // Simple Integer or Relocatable Constant + case 'n': // Simple Integer + case 's': // Relocatable Constant + case 'I': // Target registers. + case 'J': + case 'K': + case 'L': + case 'M': + case 'N': + case 'O': + case 'P': + return C_Other; + } +} + +/// isOperandValidForConstraint - Return the specified operand (possibly +/// modified) if the specified SDOperand is valid for the specified target +/// constraint letter, otherwise return null. +SDOperand TargetLowering::isOperandValidForConstraint(SDOperand Op, + char ConstraintLetter, + SelectionDAG &DAG) { + switch (ConstraintLetter) { + default: return SDOperand(0,0); + case 'i': // Simple Integer or Relocatable Constant + case 'n': // Simple Integer + case 's': // Relocatable Constant + return Op; // FIXME: not right. + } +} + +std::vector TargetLowering:: +getRegClassForInlineAsmConstraint(const std::string &Constraint, + MVT::ValueType VT) const { + return std::vector(); +} + + +std::pair TargetLowering:: +getRegForInlineAsmConstraint(const std::string &Constraint, + MVT::ValueType VT) const { + if (Constraint[0] != '{') + return std::pair(0, 0); + assert(*(Constraint.end()-1) == '}' && "Not a brace enclosed constraint?"); + + // Remove the braces from around the name. + std::string RegName(Constraint.begin()+1, Constraint.end()-1); + + // Figure out which register class contains this reg. + const MRegisterInfo *RI = TM.getRegisterInfo(); + for (MRegisterInfo::regclass_iterator RCI = RI->regclass_begin(), + E = RI->regclass_end(); RCI != E; ++RCI) { + const TargetRegisterClass *RC = *RCI; + + // If none of the the value types for this register class are valid, we + // can't use it. For example, 64-bit reg classes on 32-bit targets. + bool isLegal = false; + for (TargetRegisterClass::vt_iterator I = RC->vt_begin(), E = RC->vt_end(); + I != E; ++I) { + if (isTypeLegal(*I)) { + isLegal = true; + break; + } + } + + if (!isLegal) continue; + + for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end(); + I != E; ++I) { + if (StringsEqualNoCase(RegName, RI->get(*I).Name)) + return std::make_pair(*I, RC); + } + } + + return std::pair(0, 0); +} + +//===----------------------------------------------------------------------===// +// Loop Strength Reduction hooks +//===----------------------------------------------------------------------===// + +/// isLegalAddressImmediate - Return true if the integer value or +/// GlobalValue can be used as the offset of the target addressing mode. +bool TargetLowering::isLegalAddressImmediate(int64_t V) const { + return false; +} +bool TargetLowering::isLegalAddressImmediate(GlobalValue *GV) const { + return false; +} + + +// Magic for divide replacement + +struct ms { + int64_t m; // magic number + int64_t s; // shift amount +}; + +struct mu { + uint64_t m; // magic number + int64_t a; // add indicator + int64_t s; // shift amount +}; + +/// magic - calculate the magic numbers required to codegen an integer sdiv as +/// a sequence of multiply and shifts. Requires that the divisor not be 0, 1, +/// or -1. +static ms magic32(int32_t d) { + int32_t p; + uint32_t ad, anc, delta, q1, r1, q2, r2, t; + const uint32_t two31 = 0x80000000U; + struct ms mag; + + ad = abs(d); + t = two31 + ((uint32_t)d >> 31); + anc = t - 1 - t%ad; // absolute value of nc + p = 31; // initialize p + q1 = two31/anc; // initialize q1 = 2p/abs(nc) + r1 = two31 - q1*anc; // initialize r1 = rem(2p,abs(nc)) + q2 = two31/ad; // initialize q2 = 2p/abs(d) + r2 = two31 - q2*ad; // initialize r2 = rem(2p,abs(d)) + do { + p = p + 1; + q1 = 2*q1; // update q1 = 2p/abs(nc) + r1 = 2*r1; // update r1 = rem(2p/abs(nc)) + if (r1 >= anc) { // must be unsigned comparison + q1 = q1 + 1; + r1 = r1 - anc; + } + q2 = 2*q2; // update q2 = 2p/abs(d) + r2 = 2*r2; // update r2 = rem(2p/abs(d)) + if (r2 >= ad) { // must be unsigned comparison + q2 = q2 + 1; + r2 = r2 - ad; + } + delta = ad - r2; + } while (q1 < delta || (q1 == delta && r1 == 0)); + + mag.m = (int32_t)(q2 + 1); // make sure to sign extend + if (d < 0) mag.m = -mag.m; // resulting magic number + mag.s = p - 32; // resulting shift + return mag; +} + +/// magicu - calculate the magic numbers required to codegen an integer udiv as +/// a sequence of multiply, add and shifts. Requires that the divisor not be 0. +static mu magicu32(uint32_t d) { + int32_t p; + uint32_t nc, delta, q1, r1, q2, r2; + struct mu magu; + magu.a = 0; // initialize "add" indicator + nc = - 1 - (-d)%d; + p = 31; // initialize p + q1 = 0x80000000/nc; // initialize q1 = 2p/nc + r1 = 0x80000000 - q1*nc; // initialize r1 = rem(2p,nc) + q2 = 0x7FFFFFFF/d; // initialize q2 = (2p-1)/d + r2 = 0x7FFFFFFF - q2*d; // initialize r2 = rem((2p-1),d) + do { + p = p + 1; + if (r1 >= nc - r1 ) { + q1 = 2*q1 + 1; // update q1 + r1 = 2*r1 - nc; // update r1 + } + else { + q1 = 2*q1; // update q1 + r1 = 2*r1; // update r1 + } + if (r2 + 1 >= d - r2) { + if (q2 >= 0x7FFFFFFF) magu.a = 1; + q2 = 2*q2 + 1; // update q2 + r2 = 2*r2 + 1 - d; // update r2 + } + else { + if (q2 >= 0x80000000) magu.a = 1; + q2 = 2*q2; // update q2 + r2 = 2*r2 + 1; // update r2 + } + delta = d - 1 - r2; + } while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0))); + magu.m = q2 + 1; // resulting magic number + magu.s = p - 32; // resulting shift + return magu; +} + +/// magic - calculate the magic numbers required to codegen an integer sdiv as +/// a sequence of multiply and shifts. Requires that the divisor not be 0, 1, +/// or -1. +static ms magic64(int64_t d) { + int64_t p; + uint64_t ad, anc, delta, q1, r1, q2, r2, t; + const uint64_t two63 = 9223372036854775808ULL; // 2^63 + struct ms mag; + + ad = d >= 0 ? d : -d; + t = two63 + ((uint64_t)d >> 63); + anc = t - 1 - t%ad; // absolute value of nc + p = 63; // initialize p + q1 = two63/anc; // initialize q1 = 2p/abs(nc) + r1 = two63 - q1*anc; // initialize r1 = rem(2p,abs(nc)) + q2 = two63/ad; // initialize q2 = 2p/abs(d) + r2 = two63 - q2*ad; // initialize r2 = rem(2p,abs(d)) + do { + p = p + 1; + q1 = 2*q1; // update q1 = 2p/abs(nc) + r1 = 2*r1; // update r1 = rem(2p/abs(nc)) + if (r1 >= anc) { // must be unsigned comparison + q1 = q1 + 1; + r1 = r1 - anc; + } + q2 = 2*q2; // update q2 = 2p/abs(d) + r2 = 2*r2; // update r2 = rem(2p/abs(d)) + if (r2 >= ad) { // must be unsigned comparison + q2 = q2 + 1; + r2 = r2 - ad; + } + delta = ad - r2; + } while (q1 < delta || (q1 == delta && r1 == 0)); + + mag.m = q2 + 1; + if (d < 0) mag.m = -mag.m; // resulting magic number + mag.s = p - 64; // resulting shift + return mag; +} + +/// magicu - calculate the magic numbers required to codegen an integer udiv as +/// a sequence of multiply, add and shifts. Requires that the divisor not be 0. +static mu magicu64(uint64_t d) +{ + int64_t p; + uint64_t nc, delta, q1, r1, q2, r2; + struct mu magu; + magu.a = 0; // initialize "add" indicator + nc = - 1 - (-d)%d; + p = 63; // initialize p + q1 = 0x8000000000000000ull/nc; // initialize q1 = 2p/nc + r1 = 0x8000000000000000ull - q1*nc; // initialize r1 = rem(2p,nc) + q2 = 0x7FFFFFFFFFFFFFFFull/d; // initialize q2 = (2p-1)/d + r2 = 0x7FFFFFFFFFFFFFFFull - q2*d; // initialize r2 = rem((2p-1),d) + do { + p = p + 1; + if (r1 >= nc - r1 ) { + q1 = 2*q1 + 1; // update q1 + r1 = 2*r1 - nc; // update r1 + } + else { + q1 = 2*q1; // update q1 + r1 = 2*r1; // update r1 + } + if (r2 + 1 >= d - r2) { + if (q2 >= 0x7FFFFFFFFFFFFFFFull) magu.a = 1; + q2 = 2*q2 + 1; // update q2 + r2 = 2*r2 + 1 - d; // update r2 + } + else { + if (q2 >= 0x8000000000000000ull) magu.a = 1; + q2 = 2*q2; // update q2 + r2 = 2*r2 + 1; // update r2 + } + delta = d - 1 - r2; + } while (p < 128 && (q1 < delta || (q1 == delta && r1 == 0))); + magu.m = q2 + 1; // resulting magic number + magu.s = p - 64; // resulting shift + return magu; +} + +/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, +/// return a DAG expression to select that will generate the same value by +/// multiplying by a magic number. See: +/// +SDOperand TargetLowering::BuildSDIV(SDNode *N, SelectionDAG &DAG, + std::vector* Created) const { + MVT::ValueType VT = N->getValueType(0); + + // Check to see if we can do this. + if (!isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64)) + return SDOperand(); // BuildSDIV only operates on i32 or i64 + if (!isOperationLegal(ISD::MULHS, VT)) + return SDOperand(); // Make sure the target supports MULHS. + + int64_t d = cast(N->getOperand(1))->getSignExtended(); + ms magics = (VT == MVT::i32) ? magic32(d) : magic64(d); + + // Multiply the numerator (operand 0) by the magic value + SDOperand Q = DAG.getNode(ISD::MULHS, VT, N->getOperand(0), + DAG.getConstant(magics.m, VT)); + // If d > 0 and m < 0, add the numerator + if (d > 0 && magics.m < 0) { + Q = DAG.getNode(ISD::ADD, VT, Q, N->getOperand(0)); + if (Created) + Created->push_back(Q.Val); + } + // If d < 0 and m > 0, subtract the numerator. + if (d < 0 && magics.m > 0) { + Q = DAG.getNode(ISD::SUB, VT, Q, N->getOperand(0)); + if (Created) + Created->push_back(Q.Val); + } + // Shift right algebraic if shift value is nonzero + if (magics.s > 0) { + Q = DAG.getNode(ISD::SRA, VT, Q, + DAG.getConstant(magics.s, getShiftAmountTy())); + if (Created) + Created->push_back(Q.Val); + } + // Extract the sign bit and add it to the quotient + SDOperand T = + DAG.getNode(ISD::SRL, VT, Q, DAG.getConstant(MVT::getSizeInBits(VT)-1, + getShiftAmountTy())); + if (Created) + Created->push_back(T.Val); + return DAG.getNode(ISD::ADD, VT, Q, T); +} + +/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, +/// return a DAG expression to select that will generate the same value by +/// multiplying by a magic number. See: +/// +SDOperand TargetLowering::BuildUDIV(SDNode *N, SelectionDAG &DAG, + std::vector* Created) const { + MVT::ValueType VT = N->getValueType(0); + + // Check to see if we can do this. + if (!isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64)) + return SDOperand(); // BuildUDIV only operates on i32 or i64 + if (!isOperationLegal(ISD::MULHU, VT)) + return SDOperand(); // Make sure the target supports MULHU. + + uint64_t d = cast(N->getOperand(1))->getValue(); + mu magics = (VT == MVT::i32) ? magicu32(d) : magicu64(d); + + // Multiply the numerator (operand 0) by the magic value + SDOperand Q = DAG.getNode(ISD::MULHU, VT, N->getOperand(0), + DAG.getConstant(magics.m, VT)); + if (Created) + Created->push_back(Q.Val); + + if (magics.a == 0) { + return DAG.getNode(ISD::SRL, VT, Q, + DAG.getConstant(magics.s, getShiftAmountTy())); + } else { + SDOperand NPQ = DAG.getNode(ISD::SUB, VT, N->getOperand(0), Q); + if (Created) + Created->push_back(NPQ.Val); + NPQ = DAG.getNode(ISD::SRL, VT, NPQ, + DAG.getConstant(1, getShiftAmountTy())); + if (Created) + Created->push_back(NPQ.Val); + NPQ = DAG.getNode(ISD::ADD, VT, NPQ, Q); + if (Created) + Created->push_back(NPQ.Val); + return DAG.getNode(ISD::SRL, VT, NPQ, + DAG.getConstant(magics.s-1, getShiftAmountTy())); + } +}