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      1 //===-- llvm/CodeGen/ISDOpcodes.h - CodeGen opcodes -------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file declares codegen opcodes and related utilities.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CODEGEN_ISDOPCODES_H
     15 #define LLVM_CODEGEN_ISDOPCODES_H
     16 
     17 namespace llvm {
     18 
     19 /// ISD namespace - This namespace contains an enum which represents all of the
     20 /// SelectionDAG node types and value types.
     21 ///
     22 namespace ISD {
     23 
     24   //===--------------------------------------------------------------------===//
     25   /// ISD::NodeType enum - This enum defines the target-independent operators
     26   /// for a SelectionDAG.
     27   ///
     28   /// Targets may also define target-dependent operator codes for SDNodes. For
     29   /// example, on x86, these are the enum values in the X86ISD namespace.
     30   /// Targets should aim to use target-independent operators to model their
     31   /// instruction sets as much as possible, and only use target-dependent
     32   /// operators when they have special requirements.
     33   ///
     34   /// Finally, during and after selection proper, SNodes may use special
     35   /// operator codes that correspond directly with MachineInstr opcodes. These
     36   /// are used to represent selected instructions. See the isMachineOpcode()
     37   /// and getMachineOpcode() member functions of SDNode.
     38   ///
     39   enum NodeType {
     40     /// DELETED_NODE - This is an illegal value that is used to catch
     41     /// errors.  This opcode is not a legal opcode for any node.
     42     DELETED_NODE,
     43 
     44     /// EntryToken - This is the marker used to indicate the start of a region.
     45     EntryToken,
     46 
     47     /// TokenFactor - This node takes multiple tokens as input and produces a
     48     /// single token result. This is used to represent the fact that the operand
     49     /// operators are independent of each other.
     50     TokenFactor,
     51 
     52     /// AssertSext, AssertZext - These nodes record if a register contains a
     53     /// value that has already been zero or sign extended from a narrower type.
     54     /// These nodes take two operands.  The first is the node that has already
     55     /// been extended, and the second is a value type node indicating the width
     56     /// of the extension
     57     AssertSext, AssertZext,
     58 
     59     /// Various leaf nodes.
     60     BasicBlock, VALUETYPE, CONDCODE, Register, RegisterMask,
     61     Constant, ConstantFP,
     62     GlobalAddress, GlobalTLSAddress, FrameIndex,
     63     JumpTable, ConstantPool, ExternalSymbol, BlockAddress,
     64 
     65     /// The address of the GOT
     66     GLOBAL_OFFSET_TABLE,
     67 
     68     /// FRAMEADDR, RETURNADDR - These nodes represent llvm.frameaddress and
     69     /// llvm.returnaddress on the DAG.  These nodes take one operand, the index
     70     /// of the frame or return address to return.  An index of zero corresponds
     71     /// to the current function's frame or return address, an index of one to
     72     /// the parent's frame or return address, and so on.
     73     FRAMEADDR, RETURNADDR, ADDROFRETURNADDR,
     74 
     75     /// LOCAL_RECOVER - Represents the llvm.localrecover intrinsic.
     76     /// Materializes the offset from the local object pointer of another
     77     /// function to a particular local object passed to llvm.localescape. The
     78     /// operand is the MCSymbol label used to represent this offset, since
     79     /// typically the offset is not known until after code generation of the
     80     /// parent.
     81     LOCAL_RECOVER,
     82 
     83     /// READ_REGISTER, WRITE_REGISTER - This node represents llvm.register on
     84     /// the DAG, which implements the named register global variables extension.
     85     READ_REGISTER,
     86     WRITE_REGISTER,
     87 
     88     /// FRAME_TO_ARGS_OFFSET - This node represents offset from frame pointer to
     89     /// first (possible) on-stack argument. This is needed for correct stack
     90     /// adjustment during unwind.
     91     FRAME_TO_ARGS_OFFSET,
     92 
     93     /// EH_DWARF_CFA - This node represents the pointer to the DWARF Canonical
     94     /// Frame Address (CFA), generally the value of the stack pointer at the
     95     /// call site in the previous frame.
     96     EH_DWARF_CFA,
     97 
     98     /// OUTCHAIN = EH_RETURN(INCHAIN, OFFSET, HANDLER) - This node represents
     99     /// 'eh_return' gcc dwarf builtin, which is used to return from
    100     /// exception. The general meaning is: adjust stack by OFFSET and pass
    101     /// execution to HANDLER. Many platform-related details also :)
    102     EH_RETURN,
    103 
    104     /// RESULT, OUTCHAIN = EH_SJLJ_SETJMP(INCHAIN, buffer)
    105     /// This corresponds to the eh.sjlj.setjmp intrinsic.
    106     /// It takes an input chain and a pointer to the jump buffer as inputs
    107     /// and returns an outchain.
    108     EH_SJLJ_SETJMP,
    109 
    110     /// OUTCHAIN = EH_SJLJ_LONGJMP(INCHAIN, buffer)
    111     /// This corresponds to the eh.sjlj.longjmp intrinsic.
    112     /// It takes an input chain and a pointer to the jump buffer as inputs
    113     /// and returns an outchain.
    114     EH_SJLJ_LONGJMP,
    115 
    116     /// OUTCHAIN = EH_SJLJ_SETUP_DISPATCH(INCHAIN)
    117     /// The target initializes the dispatch table here.
    118     EH_SJLJ_SETUP_DISPATCH,
    119 
    120     /// TargetConstant* - Like Constant*, but the DAG does not do any folding,
    121     /// simplification, or lowering of the constant. They are used for constants
    122     /// which are known to fit in the immediate fields of their users, or for
    123     /// carrying magic numbers which are not values which need to be
    124     /// materialized in registers.
    125     TargetConstant,
    126     TargetConstantFP,
    127 
    128     /// TargetGlobalAddress - Like GlobalAddress, but the DAG does no folding or
    129     /// anything else with this node, and this is valid in the target-specific
    130     /// dag, turning into a GlobalAddress operand.
    131     TargetGlobalAddress,
    132     TargetGlobalTLSAddress,
    133     TargetFrameIndex,
    134     TargetJumpTable,
    135     TargetConstantPool,
    136     TargetExternalSymbol,
    137     TargetBlockAddress,
    138 
    139     MCSymbol,
    140 
    141     /// TargetIndex - Like a constant pool entry, but with completely
    142     /// target-dependent semantics. Holds target flags, a 32-bit index, and a
    143     /// 64-bit index. Targets can use this however they like.
    144     TargetIndex,
    145 
    146     /// RESULT = INTRINSIC_WO_CHAIN(INTRINSICID, arg1, arg2, ...)
    147     /// This node represents a target intrinsic function with no side effects.
    148     /// The first operand is the ID number of the intrinsic from the
    149     /// llvm::Intrinsic namespace.  The operands to the intrinsic follow.  The
    150     /// node returns the result of the intrinsic.
    151     INTRINSIC_WO_CHAIN,
    152 
    153     /// RESULT,OUTCHAIN = INTRINSIC_W_CHAIN(INCHAIN, INTRINSICID, arg1, ...)
    154     /// This node represents a target intrinsic function with side effects that
    155     /// returns a result.  The first operand is a chain pointer.  The second is
    156     /// the ID number of the intrinsic from the llvm::Intrinsic namespace.  The
    157     /// operands to the intrinsic follow.  The node has two results, the result
    158     /// of the intrinsic and an output chain.
    159     INTRINSIC_W_CHAIN,
    160 
    161     /// OUTCHAIN = INTRINSIC_VOID(INCHAIN, INTRINSICID, arg1, arg2, ...)
    162     /// This node represents a target intrinsic function with side effects that
    163     /// does not return a result.  The first operand is a chain pointer.  The
    164     /// second is the ID number of the intrinsic from the llvm::Intrinsic
    165     /// namespace.  The operands to the intrinsic follow.
    166     INTRINSIC_VOID,
    167 
    168     /// CopyToReg - This node has three operands: a chain, a register number to
    169     /// set to this value, and a value.
    170     CopyToReg,
    171 
    172     /// CopyFromReg - This node indicates that the input value is a virtual or
    173     /// physical register that is defined outside of the scope of this
    174     /// SelectionDAG.  The register is available from the RegisterSDNode object.
    175     CopyFromReg,
    176 
    177     /// UNDEF - An undefined node.
    178     UNDEF,
    179 
    180     /// EXTRACT_ELEMENT - This is used to get the lower or upper (determined by
    181     /// a Constant, which is required to be operand #1) half of the integer or
    182     /// float value specified as operand #0.  This is only for use before
    183     /// legalization, for values that will be broken into multiple registers.
    184     EXTRACT_ELEMENT,
    185 
    186     /// BUILD_PAIR - This is the opposite of EXTRACT_ELEMENT in some ways.
    187     /// Given two values of the same integer value type, this produces a value
    188     /// twice as big.  Like EXTRACT_ELEMENT, this can only be used before
    189     /// legalization.
    190     BUILD_PAIR,
    191 
    192     /// MERGE_VALUES - This node takes multiple discrete operands and returns
    193     /// them all as its individual results.  This nodes has exactly the same
    194     /// number of inputs and outputs. This node is useful for some pieces of the
    195     /// code generator that want to think about a single node with multiple
    196     /// results, not multiple nodes.
    197     MERGE_VALUES,
    198 
    199     /// Simple integer binary arithmetic operators.
    200     ADD, SUB, MUL, SDIV, UDIV, SREM, UREM,
    201 
    202     /// SMUL_LOHI/UMUL_LOHI - Multiply two integers of type iN, producing
    203     /// a signed/unsigned value of type i[2*N], and return the full value as
    204     /// two results, each of type iN.
    205     SMUL_LOHI, UMUL_LOHI,
    206 
    207     /// SDIVREM/UDIVREM - Divide two integers and produce both a quotient and
    208     /// remainder result.
    209     SDIVREM, UDIVREM,
    210 
    211     /// CARRY_FALSE - This node is used when folding other nodes,
    212     /// like ADDC/SUBC, which indicate the carry result is always false.
    213     CARRY_FALSE,
    214 
    215     /// Carry-setting nodes for multiple precision addition and subtraction.
    216     /// These nodes take two operands of the same value type, and produce two
    217     /// results.  The first result is the normal add or sub result, the second
    218     /// result is the carry flag result.
    219     /// FIXME: These nodes are deprecated in favor of ADDCARRY and SUBCARRY.
    220     /// They are kept around for now to provide a smooth transition path
    221     /// toward the use of ADDCARRY/SUBCARRY and will eventually be removed.
    222     ADDC, SUBC,
    223 
    224     /// Carry-using nodes for multiple precision addition and subtraction. These
    225     /// nodes take three operands: The first two are the normal lhs and rhs to
    226     /// the add or sub, and the third is the input carry flag.  These nodes
    227     /// produce two results; the normal result of the add or sub, and the output
    228     /// carry flag.  These nodes both read and write a carry flag to allow them
    229     /// to them to be chained together for add and sub of arbitrarily large
    230     /// values.
    231     ADDE, SUBE,
    232 
    233     /// Carry-using nodes for multiple precision addition and subtraction.
    234     /// These nodes take three operands: The first two are the normal lhs and
    235     /// rhs to the add or sub, and the third is a boolean indicating if there
    236     /// is an incoming carry. These nodes produce two results: the normal
    237     /// result of the add or sub, and the output carry so they can be chained
    238     /// together. The use of this opcode is preferable to adde/sube if the
    239     /// target supports it, as the carry is a regular value rather than a
    240     /// glue, which allows further optimisation.
    241     ADDCARRY, SUBCARRY,
    242 
    243     /// RESULT, BOOL = [SU]ADDO(LHS, RHS) - Overflow-aware nodes for addition.
    244     /// These nodes take two operands: the normal LHS and RHS to the add. They
    245     /// produce two results: the normal result of the add, and a boolean that
    246     /// indicates if an overflow occurred (*not* a flag, because it may be store
    247     /// to memory, etc.).  If the type of the boolean is not i1 then the high
    248     /// bits conform to getBooleanContents.
    249     /// These nodes are generated from llvm.[su]add.with.overflow intrinsics.
    250     SADDO, UADDO,
    251 
    252     /// Same for subtraction.
    253     SSUBO, USUBO,
    254 
    255     /// Same for multiplication.
    256     SMULO, UMULO,
    257 
    258     /// Simple binary floating point operators.
    259     FADD, FSUB, FMUL, FDIV, FREM,
    260 
    261     /// Constrained versions of the binary floating point operators.
    262     /// These will be lowered to the simple operators before final selection.
    263     /// They are used to limit optimizations while the DAG is being
    264     /// optimized.
    265     STRICT_FADD, STRICT_FSUB, STRICT_FMUL, STRICT_FDIV, STRICT_FREM,
    266     STRICT_FMA,
    267 
    268     /// Constrained versions of libm-equivalent floating point intrinsics.
    269     /// These will be lowered to the equivalent non-constrained pseudo-op
    270     /// (or expanded to the equivalent library call) before final selection.
    271     /// They are used to limit optimizations while the DAG is being optimized.
    272     STRICT_FSQRT, STRICT_FPOW, STRICT_FPOWI, STRICT_FSIN, STRICT_FCOS,
    273     STRICT_FEXP, STRICT_FEXP2, STRICT_FLOG, STRICT_FLOG10, STRICT_FLOG2,
    274     STRICT_FRINT, STRICT_FNEARBYINT,
    275 
    276     /// FMA - Perform a * b + c with no intermediate rounding step.
    277     FMA,
    278 
    279     /// FMAD - Perform a * b + c, while getting the same result as the
    280     /// separately rounded operations.
    281     FMAD,
    282 
    283     /// FCOPYSIGN(X, Y) - Return the value of X with the sign of Y.  NOTE: This
    284     /// DAG node does not require that X and Y have the same type, just that
    285     /// they are both floating point.  X and the result must have the same type.
    286     /// FCOPYSIGN(f32, f64) is allowed.
    287     FCOPYSIGN,
    288 
    289     /// INT = FGETSIGN(FP) - Return the sign bit of the specified floating point
    290     /// value as an integer 0/1 value.
    291     FGETSIGN,
    292 
    293     /// Returns platform specific canonical encoding of a floating point number.
    294     FCANONICALIZE,
    295 
    296     /// BUILD_VECTOR(ELT0, ELT1, ELT2, ELT3,...) - Return a vector with the
    297     /// specified, possibly variable, elements.  The number of elements is
    298     /// required to be a power of two.  The types of the operands must all be
    299     /// the same and must match the vector element type, except that integer
    300     /// types are allowed to be larger than the element type, in which case
    301     /// the operands are implicitly truncated.
    302     BUILD_VECTOR,
    303 
    304     /// INSERT_VECTOR_ELT(VECTOR, VAL, IDX) - Returns VECTOR with the element
    305     /// at IDX replaced with VAL.  If the type of VAL is larger than the vector
    306     /// element type then VAL is truncated before replacement.
    307     INSERT_VECTOR_ELT,
    308 
    309     /// EXTRACT_VECTOR_ELT(VECTOR, IDX) - Returns a single element from VECTOR
    310     /// identified by the (potentially variable) element number IDX.  If the
    311     /// return type is an integer type larger than the element type of the
    312     /// vector, the result is extended to the width of the return type. In
    313     /// that case, the high bits are undefined.
    314     EXTRACT_VECTOR_ELT,
    315 
    316     /// CONCAT_VECTORS(VECTOR0, VECTOR1, ...) - Given a number of values of
    317     /// vector type with the same length and element type, this produces a
    318     /// concatenated vector result value, with length equal to the sum of the
    319     /// lengths of the input vectors.
    320     CONCAT_VECTORS,
    321 
    322     /// INSERT_SUBVECTOR(VECTOR1, VECTOR2, IDX) - Returns a vector
    323     /// with VECTOR2 inserted into VECTOR1 at the (potentially
    324     /// variable) element number IDX, which must be a multiple of the
    325     /// VECTOR2 vector length.  The elements of VECTOR1 starting at
    326     /// IDX are overwritten with VECTOR2.  Elements IDX through
    327     /// vector_length(VECTOR2) must be valid VECTOR1 indices.
    328     INSERT_SUBVECTOR,
    329 
    330     /// EXTRACT_SUBVECTOR(VECTOR, IDX) - Returns a subvector from VECTOR (an
    331     /// vector value) starting with the element number IDX, which must be a
    332     /// constant multiple of the result vector length.
    333     EXTRACT_SUBVECTOR,
    334 
    335     /// VECTOR_SHUFFLE(VEC1, VEC2) - Returns a vector, of the same type as
    336     /// VEC1/VEC2.  A VECTOR_SHUFFLE node also contains an array of constant int
    337     /// values that indicate which value (or undef) each result element will
    338     /// get.  These constant ints are accessible through the
    339     /// ShuffleVectorSDNode class.  This is quite similar to the Altivec
    340     /// 'vperm' instruction, except that the indices must be constants and are
    341     /// in terms of the element size of VEC1/VEC2, not in terms of bytes.
    342     VECTOR_SHUFFLE,
    343 
    344     /// SCALAR_TO_VECTOR(VAL) - This represents the operation of loading a
    345     /// scalar value into element 0 of the resultant vector type.  The top
    346     /// elements 1 to N-1 of the N-element vector are undefined.  The type
    347     /// of the operand must match the vector element type, except when they
    348     /// are integer types.  In this case the operand is allowed to be wider
    349     /// than the vector element type, and is implicitly truncated to it.
    350     SCALAR_TO_VECTOR,
    351 
    352     /// MULHU/MULHS - Multiply high - Multiply two integers of type iN,
    353     /// producing an unsigned/signed value of type i[2*N], then return the top
    354     /// part.
    355     MULHU, MULHS,
    356 
    357     /// [US]{MIN/MAX} - Binary minimum or maximum or signed or unsigned
    358     /// integers.
    359     SMIN, SMAX, UMIN, UMAX,
    360 
    361     /// Bitwise operators - logical and, logical or, logical xor.
    362     AND, OR, XOR,
    363 
    364     /// ABS - Determine the unsigned absolute value of a signed integer value of
    365     /// the same bitwidth.
    366     /// Note: A value of INT_MIN will return INT_MIN, no saturation or overflow
    367     /// is performed.
    368     ABS,
    369 
    370     /// Shift and rotation operations.  After legalization, the type of the
    371     /// shift amount is known to be TLI.getShiftAmountTy().  Before legalization
    372     /// the shift amount can be any type, but care must be taken to ensure it is
    373     /// large enough.  TLI.getShiftAmountTy() is i8 on some targets, but before
    374     /// legalization, types like i1024 can occur and i8 doesn't have enough bits
    375     /// to represent the shift amount.
    376     /// When the 1st operand is a vector, the shift amount must be in the same
    377     /// type. (TLI.getShiftAmountTy() will return the same type when the input
    378     /// type is a vector.)
    379     SHL, SRA, SRL, ROTL, ROTR,
    380 
    381     /// Byte Swap and Counting operators.
    382     BSWAP, CTTZ, CTLZ, CTPOP, BITREVERSE,
    383 
    384     /// Bit counting operators with an undefined result for zero inputs.
    385     CTTZ_ZERO_UNDEF, CTLZ_ZERO_UNDEF,
    386 
    387     /// Select(COND, TRUEVAL, FALSEVAL).  If the type of the boolean COND is not
    388     /// i1 then the high bits must conform to getBooleanContents.
    389     SELECT,
    390 
    391     /// Select with a vector condition (op #0) and two vector operands (ops #1
    392     /// and #2), returning a vector result.  All vectors have the same length.
    393     /// Much like the scalar select and setcc, each bit in the condition selects
    394     /// whether the corresponding result element is taken from op #1 or op #2.
    395     /// At first, the VSELECT condition is of vXi1 type. Later, targets may
    396     /// change the condition type in order to match the VSELECT node using a
    397     /// pattern. The condition follows the BooleanContent format of the target.
    398     VSELECT,
    399 
    400     /// Select with condition operator - This selects between a true value and
    401     /// a false value (ops #2 and #3) based on the boolean result of comparing
    402     /// the lhs and rhs (ops #0 and #1) of a conditional expression with the
    403     /// condition code in op #4, a CondCodeSDNode.
    404     SELECT_CC,
    405 
    406     /// SetCC operator - This evaluates to a true value iff the condition is
    407     /// true.  If the result value type is not i1 then the high bits conform
    408     /// to getBooleanContents.  The operands to this are the left and right
    409     /// operands to compare (ops #0, and #1) and the condition code to compare
    410     /// them with (op #2) as a CondCodeSDNode. If the operands are vector types
    411     /// then the result type must also be a vector type.
    412     SETCC,
    413 
    414     /// Like SetCC, ops #0 and #1 are the LHS and RHS operands to compare, and
    415     /// op #2 is a *carry value*. This operator checks the result of
    416     /// "LHS - RHS - Carry", and can be used to compare two wide integers:
    417     /// (setcce lhshi rhshi (subc lhslo rhslo) cc). Only valid for integers.
    418     /// FIXME: This node is deprecated in favor of SETCCCARRY.
    419     /// It is kept around for now to provide a smooth transition path
    420     /// toward the use of SETCCCARRY and will eventually be removed.
    421     SETCCE,
    422 
    423     /// Like SetCC, ops #0 and #1 are the LHS and RHS operands to compare, but
    424     /// op #2 is a boolean indicating if there is an incoming carry. This
    425     /// operator checks the result of "LHS - RHS - Carry", and can be used to
    426     /// compare two wide integers: (setcce lhshi rhshi (subc lhslo rhslo) cc).
    427     /// Only valid for integers.
    428     SETCCCARRY,
    429 
    430     /// SHL_PARTS/SRA_PARTS/SRL_PARTS - These operators are used for expanded
    431     /// integer shift operations.  The operation ordering is:
    432     ///       [Lo,Hi] = op [LoLHS,HiLHS], Amt
    433     SHL_PARTS, SRA_PARTS, SRL_PARTS,
    434 
    435     /// Conversion operators.  These are all single input single output
    436     /// operations.  For all of these, the result type must be strictly
    437     /// wider or narrower (depending on the operation) than the source
    438     /// type.
    439 
    440     /// SIGN_EXTEND - Used for integer types, replicating the sign bit
    441     /// into new bits.
    442     SIGN_EXTEND,
    443 
    444     /// ZERO_EXTEND - Used for integer types, zeroing the new bits.
    445     ZERO_EXTEND,
    446 
    447     /// ANY_EXTEND - Used for integer types.  The high bits are undefined.
    448     ANY_EXTEND,
    449 
    450     /// TRUNCATE - Completely drop the high bits.
    451     TRUNCATE,
    452 
    453     /// [SU]INT_TO_FP - These operators convert integers (whose interpreted sign
    454     /// depends on the first letter) to floating point.
    455     SINT_TO_FP,
    456     UINT_TO_FP,
    457 
    458     /// SIGN_EXTEND_INREG - This operator atomically performs a SHL/SRA pair to
    459     /// sign extend a small value in a large integer register (e.g. sign
    460     /// extending the low 8 bits of a 32-bit register to fill the top 24 bits
    461     /// with the 7th bit).  The size of the smaller type is indicated by the 1th
    462     /// operand, a ValueType node.
    463     SIGN_EXTEND_INREG,
    464 
    465     /// ANY_EXTEND_VECTOR_INREG(Vector) - This operator represents an
    466     /// in-register any-extension of the low lanes of an integer vector. The
    467     /// result type must have fewer elements than the operand type, and those
    468     /// elements must be larger integer types such that the total size of the
    469     /// operand type and the result type match. Each of the low operand
    470     /// elements is any-extended into the corresponding, wider result
    471     /// elements with the high bits becoming undef.
    472     ANY_EXTEND_VECTOR_INREG,
    473 
    474     /// SIGN_EXTEND_VECTOR_INREG(Vector) - This operator represents an
    475     /// in-register sign-extension of the low lanes of an integer vector. The
    476     /// result type must have fewer elements than the operand type, and those
    477     /// elements must be larger integer types such that the total size of the
    478     /// operand type and the result type match. Each of the low operand
    479     /// elements is sign-extended into the corresponding, wider result
    480     /// elements.
    481     // FIXME: The SIGN_EXTEND_INREG node isn't specifically limited to
    482     // scalars, but it also doesn't handle vectors well. Either it should be
    483     // restricted to scalars or this node (and its handling) should be merged
    484     // into it.
    485     SIGN_EXTEND_VECTOR_INREG,
    486 
    487     /// ZERO_EXTEND_VECTOR_INREG(Vector) - This operator represents an
    488     /// in-register zero-extension of the low lanes of an integer vector. The
    489     /// result type must have fewer elements than the operand type, and those
    490     /// elements must be larger integer types such that the total size of the
    491     /// operand type and the result type match. Each of the low operand
    492     /// elements is zero-extended into the corresponding, wider result
    493     /// elements.
    494     ZERO_EXTEND_VECTOR_INREG,
    495 
    496     /// FP_TO_[US]INT - Convert a floating point value to a signed or unsigned
    497     /// integer.
    498     FP_TO_SINT,
    499     FP_TO_UINT,
    500 
    501     /// X = FP_ROUND(Y, TRUNC) - Rounding 'Y' from a larger floating point type
    502     /// down to the precision of the destination VT.  TRUNC is a flag, which is
    503     /// always an integer that is zero or one.  If TRUNC is 0, this is a
    504     /// normal rounding, if it is 1, this FP_ROUND is known to not change the
    505     /// value of Y.
    506     ///
    507     /// The TRUNC = 1 case is used in cases where we know that the value will
    508     /// not be modified by the node, because Y is not using any of the extra
    509     /// precision of source type.  This allows certain transformations like
    510     /// FP_EXTEND(FP_ROUND(X,1)) -> X which are not safe for
    511     /// FP_EXTEND(FP_ROUND(X,0)) because the extra bits aren't removed.
    512     FP_ROUND,
    513 
    514     /// FLT_ROUNDS_ - Returns current rounding mode:
    515     /// -1 Undefined
    516     ///  0 Round to 0
    517     ///  1 Round to nearest
    518     ///  2 Round to +inf
    519     ///  3 Round to -inf
    520     FLT_ROUNDS_,
    521 
    522     /// X = FP_ROUND_INREG(Y, VT) - This operator takes an FP register, and
    523     /// rounds it to a floating point value.  It then promotes it and returns it
    524     /// in a register of the same size.  This operation effectively just
    525     /// discards excess precision.  The type to round down to is specified by
    526     /// the VT operand, a VTSDNode.
    527     FP_ROUND_INREG,
    528 
    529     /// X = FP_EXTEND(Y) - Extend a smaller FP type into a larger FP type.
    530     FP_EXTEND,
    531 
    532     /// BITCAST - This operator converts between integer, vector and FP
    533     /// values, as if the value was stored to memory with one type and loaded
    534     /// from the same address with the other type (or equivalently for vector
    535     /// format conversions, etc).  The source and result are required to have
    536     /// the same bit size (e.g.  f32 <-> i32).  This can also be used for
    537     /// int-to-int or fp-to-fp conversions, but that is a noop, deleted by
    538     /// getNode().
    539     ///
    540     /// This operator is subtly different from the bitcast instruction from
    541     /// LLVM-IR since this node may change the bits in the register. For
    542     /// example, this occurs on big-endian NEON and big-endian MSA where the
    543     /// layout of the bits in the register depends on the vector type and this
    544     /// operator acts as a shuffle operation for some vector type combinations.
    545     BITCAST,
    546 
    547     /// ADDRSPACECAST - This operator converts between pointers of different
    548     /// address spaces.
    549     ADDRSPACECAST,
    550 
    551     /// FP16_TO_FP, FP_TO_FP16 - These operators are used to perform promotions
    552     /// and truncation for half-precision (16 bit) floating numbers. These nodes
    553     /// form a semi-softened interface for dealing with f16 (as an i16), which
    554     /// is often a storage-only type but has native conversions.
    555     FP16_TO_FP, FP_TO_FP16,
    556 
    557     /// FNEG, FABS, FSQRT, FSIN, FCOS, FPOWI, FPOW,
    558     /// FLOG, FLOG2, FLOG10, FEXP, FEXP2,
    559     /// FCEIL, FTRUNC, FRINT, FNEARBYINT, FROUND, FFLOOR - Perform various unary
    560     /// floating point operations. These are inspired by libm.
    561     FNEG, FABS, FSQRT, FSIN, FCOS, FPOWI, FPOW,
    562     FLOG, FLOG2, FLOG10, FEXP, FEXP2,
    563     FCEIL, FTRUNC, FRINT, FNEARBYINT, FROUND, FFLOOR,
    564     /// FMINNUM/FMAXNUM - Perform floating-point minimum or maximum on two
    565     /// values.
    566     /// In the case where a single input is NaN, the non-NaN input is returned.
    567     ///
    568     /// The return value of (FMINNUM 0.0, -0.0) could be either 0.0 or -0.0.
    569     FMINNUM, FMAXNUM,
    570     /// FMINNAN/FMAXNAN - Behave identically to FMINNUM/FMAXNUM, except that
    571     /// when a single input is NaN, NaN is returned.
    572     FMINNAN, FMAXNAN,
    573 
    574     /// FSINCOS - Compute both fsin and fcos as a single operation.
    575     FSINCOS,
    576 
    577     /// LOAD and STORE have token chains as their first operand, then the same
    578     /// operands as an LLVM load/store instruction, then an offset node that
    579     /// is added / subtracted from the base pointer to form the address (for
    580     /// indexed memory ops).
    581     LOAD, STORE,
    582 
    583     /// DYNAMIC_STACKALLOC - Allocate some number of bytes on the stack aligned
    584     /// to a specified boundary.  This node always has two return values: a new
    585     /// stack pointer value and a chain. The first operand is the token chain,
    586     /// the second is the number of bytes to allocate, and the third is the
    587     /// alignment boundary.  The size is guaranteed to be a multiple of the
    588     /// stack alignment, and the alignment is guaranteed to be bigger than the
    589     /// stack alignment (if required) or 0 to get standard stack alignment.
    590     DYNAMIC_STACKALLOC,
    591 
    592     /// Control flow instructions.  These all have token chains.
    593 
    594     /// BR - Unconditional branch.  The first operand is the chain
    595     /// operand, the second is the MBB to branch to.
    596     BR,
    597 
    598     /// BRIND - Indirect branch.  The first operand is the chain, the second
    599     /// is the value to branch to, which must be of the same type as the
    600     /// target's pointer type.
    601     BRIND,
    602 
    603     /// BR_JT - Jumptable branch. The first operand is the chain, the second
    604     /// is the jumptable index, the last one is the jumptable entry index.
    605     BR_JT,
    606 
    607     /// BRCOND - Conditional branch.  The first operand is the chain, the
    608     /// second is the condition, the third is the block to branch to if the
    609     /// condition is true.  If the type of the condition is not i1, then the
    610     /// high bits must conform to getBooleanContents.
    611     BRCOND,
    612 
    613     /// BR_CC - Conditional branch.  The behavior is like that of SELECT_CC, in
    614     /// that the condition is represented as condition code, and two nodes to
    615     /// compare, rather than as a combined SetCC node.  The operands in order
    616     /// are chain, cc, lhs, rhs, block to branch to if condition is true.
    617     BR_CC,
    618 
    619     /// INLINEASM - Represents an inline asm block.  This node always has two
    620     /// return values: a chain and a flag result.  The inputs are as follows:
    621     ///   Operand #0  : Input chain.
    622     ///   Operand #1  : a ExternalSymbolSDNode with a pointer to the asm string.
    623     ///   Operand #2  : a MDNodeSDNode with the !srcloc metadata.
    624     ///   Operand #3  : HasSideEffect, IsAlignStack bits.
    625     ///   After this, it is followed by a list of operands with this format:
    626     ///     ConstantSDNode: Flags that encode whether it is a mem or not, the
    627     ///                     of operands that follow, etc.  See InlineAsm.h.
    628     ///     ... however many operands ...
    629     ///   Operand #last: Optional, an incoming flag.
    630     ///
    631     /// The variable width operands are required to represent target addressing
    632     /// modes as a single "operand", even though they may have multiple
    633     /// SDOperands.
    634     INLINEASM,
    635 
    636     /// EH_LABEL - Represents a label in mid basic block used to track
    637     /// locations needed for debug and exception handling tables.  These nodes
    638     /// take a chain as input and return a chain.
    639     EH_LABEL,
    640 
    641     /// ANNOTATION_LABEL - Represents a mid basic block label used by
    642     /// annotations. This should remain within the basic block and be ordered
    643     /// with respect to other call instructions, but loads and stores may float
    644     /// past it.
    645     ANNOTATION_LABEL,
    646 
    647     /// CATCHPAD - Represents a catchpad instruction.
    648     CATCHPAD,
    649 
    650     /// CATCHRET - Represents a return from a catch block funclet. Used for
    651     /// MSVC compatible exception handling. Takes a chain operand and a
    652     /// destination basic block operand.
    653     CATCHRET,
    654 
    655     /// CLEANUPRET - Represents a return from a cleanup block funclet.  Used for
    656     /// MSVC compatible exception handling. Takes only a chain operand.
    657     CLEANUPRET,
    658 
    659     /// STACKSAVE - STACKSAVE has one operand, an input chain.  It produces a
    660     /// value, the same type as the pointer type for the system, and an output
    661     /// chain.
    662     STACKSAVE,
    663 
    664     /// STACKRESTORE has two operands, an input chain and a pointer to restore
    665     /// to it returns an output chain.
    666     STACKRESTORE,
    667 
    668     /// CALLSEQ_START/CALLSEQ_END - These operators mark the beginning and end
    669     /// of a call sequence, and carry arbitrary information that target might
    670     /// want to know.  The first operand is a chain, the rest are specified by
    671     /// the target and not touched by the DAG optimizers.
    672     /// Targets that may use stack to pass call arguments define additional
    673     /// operands:
    674     /// - size of the call frame part that must be set up within the
    675     ///   CALLSEQ_START..CALLSEQ_END pair,
    676     /// - part of the call frame prepared prior to CALLSEQ_START.
    677     /// Both these parameters must be constants, their sum is the total call
    678     /// frame size.
    679     /// CALLSEQ_START..CALLSEQ_END pairs may not be nested.
    680     CALLSEQ_START,  // Beginning of a call sequence
    681     CALLSEQ_END,    // End of a call sequence
    682 
    683     /// VAARG - VAARG has four operands: an input chain, a pointer, a SRCVALUE,
    684     /// and the alignment. It returns a pair of values: the vaarg value and a
    685     /// new chain.
    686     VAARG,
    687 
    688     /// VACOPY - VACOPY has 5 operands: an input chain, a destination pointer,
    689     /// a source pointer, a SRCVALUE for the destination, and a SRCVALUE for the
    690     /// source.
    691     VACOPY,
    692 
    693     /// VAEND, VASTART - VAEND and VASTART have three operands: an input chain,
    694     /// pointer, and a SRCVALUE.
    695     VAEND, VASTART,
    696 
    697     /// SRCVALUE - This is a node type that holds a Value* that is used to
    698     /// make reference to a value in the LLVM IR.
    699     SRCVALUE,
    700 
    701     /// MDNODE_SDNODE - This is a node that holdes an MDNode*, which is used to
    702     /// reference metadata in the IR.
    703     MDNODE_SDNODE,
    704 
    705     /// PCMARKER - This corresponds to the pcmarker intrinsic.
    706     PCMARKER,
    707 
    708     /// READCYCLECOUNTER - This corresponds to the readcyclecounter intrinsic.
    709     /// It produces a chain and one i64 value. The only operand is a chain.
    710     /// If i64 is not legal, the result will be expanded into smaller values.
    711     /// Still, it returns an i64, so targets should set legality for i64.
    712     /// The result is the content of the architecture-specific cycle
    713     /// counter-like register (or other high accuracy low latency clock source).
    714     READCYCLECOUNTER,
    715 
    716     /// HANDLENODE node - Used as a handle for various purposes.
    717     HANDLENODE,
    718 
    719     /// INIT_TRAMPOLINE - This corresponds to the init_trampoline intrinsic.  It
    720     /// takes as input a token chain, the pointer to the trampoline, the pointer
    721     /// to the nested function, the pointer to pass for the 'nest' parameter, a
    722     /// SRCVALUE for the trampoline and another for the nested function
    723     /// (allowing targets to access the original Function*).
    724     /// It produces a token chain as output.
    725     INIT_TRAMPOLINE,
    726 
    727     /// ADJUST_TRAMPOLINE - This corresponds to the adjust_trampoline intrinsic.
    728     /// It takes a pointer to the trampoline and produces a (possibly) new
    729     /// pointer to the same trampoline with platform-specific adjustments
    730     /// applied.  The pointer it returns points to an executable block of code.
    731     ADJUST_TRAMPOLINE,
    732 
    733     /// TRAP - Trapping instruction
    734     TRAP,
    735 
    736     /// DEBUGTRAP - Trap intended to get the attention of a debugger.
    737     DEBUGTRAP,
    738 
    739     /// PREFETCH - This corresponds to a prefetch intrinsic. The first operand
    740     /// is the chain.  The other operands are the address to prefetch,
    741     /// read / write specifier, locality specifier and instruction / data cache
    742     /// specifier.
    743     PREFETCH,
    744 
    745     /// OUTCHAIN = ATOMIC_FENCE(INCHAIN, ordering, scope)
    746     /// This corresponds to the fence instruction. It takes an input chain, and
    747     /// two integer constants: an AtomicOrdering and a SynchronizationScope.
    748     ATOMIC_FENCE,
    749 
    750     /// Val, OUTCHAIN = ATOMIC_LOAD(INCHAIN, ptr)
    751     /// This corresponds to "load atomic" instruction.
    752     ATOMIC_LOAD,
    753 
    754     /// OUTCHAIN = ATOMIC_STORE(INCHAIN, ptr, val)
    755     /// This corresponds to "store atomic" instruction.
    756     ATOMIC_STORE,
    757 
    758     /// Val, OUTCHAIN = ATOMIC_CMP_SWAP(INCHAIN, ptr, cmp, swap)
    759     /// For double-word atomic operations:
    760     /// ValLo, ValHi, OUTCHAIN = ATOMIC_CMP_SWAP(INCHAIN, ptr, cmpLo, cmpHi,
    761     ///                                          swapLo, swapHi)
    762     /// This corresponds to the cmpxchg instruction.
    763     ATOMIC_CMP_SWAP,
    764 
    765     /// Val, Success, OUTCHAIN
    766     ///     = ATOMIC_CMP_SWAP_WITH_SUCCESS(INCHAIN, ptr, cmp, swap)
    767     /// N.b. this is still a strong cmpxchg operation, so
    768     /// Success == "Val == cmp".
    769     ATOMIC_CMP_SWAP_WITH_SUCCESS,
    770 
    771     /// Val, OUTCHAIN = ATOMIC_SWAP(INCHAIN, ptr, amt)
    772     /// Val, OUTCHAIN = ATOMIC_LOAD_[OpName](INCHAIN, ptr, amt)
    773     /// For double-word atomic operations:
    774     /// ValLo, ValHi, OUTCHAIN = ATOMIC_SWAP(INCHAIN, ptr, amtLo, amtHi)
    775     /// ValLo, ValHi, OUTCHAIN = ATOMIC_LOAD_[OpName](INCHAIN, ptr, amtLo, amtHi)
    776     /// These correspond to the atomicrmw instruction.
    777     ATOMIC_SWAP,
    778     ATOMIC_LOAD_ADD,
    779     ATOMIC_LOAD_SUB,
    780     ATOMIC_LOAD_AND,
    781     ATOMIC_LOAD_OR,
    782     ATOMIC_LOAD_XOR,
    783     ATOMIC_LOAD_NAND,
    784     ATOMIC_LOAD_MIN,
    785     ATOMIC_LOAD_MAX,
    786     ATOMIC_LOAD_UMIN,
    787     ATOMIC_LOAD_UMAX,
    788 
    789     // Masked load and store - consecutive vector load and store operations
    790     // with additional mask operand that prevents memory accesses to the
    791     // masked-off lanes.
    792     MLOAD, MSTORE,
    793 
    794     // Masked gather and scatter - load and store operations for a vector of
    795     // random addresses with additional mask operand that prevents memory
    796     // accesses to the masked-off lanes.
    797     MGATHER, MSCATTER,
    798 
    799     /// This corresponds to the llvm.lifetime.* intrinsics. The first operand
    800     /// is the chain and the second operand is the alloca pointer.
    801     LIFETIME_START, LIFETIME_END,
    802 
    803     /// GC_TRANSITION_START/GC_TRANSITION_END - These operators mark the
    804     /// beginning and end of GC transition  sequence, and carry arbitrary
    805     /// information that target might need for lowering.  The first operand is
    806     /// a chain, the rest are specified by the target and not touched by the DAG
    807     /// optimizers. GC_TRANSITION_START..GC_TRANSITION_END pairs may not be
    808     /// nested.
    809     GC_TRANSITION_START,
    810     GC_TRANSITION_END,
    811 
    812     /// GET_DYNAMIC_AREA_OFFSET - get offset from native SP to the address of
    813     /// the most recent dynamic alloca. For most targets that would be 0, but
    814     /// for some others (e.g. PowerPC, PowerPC64) that would be compile-time
    815     /// known nonzero constant. The only operand here is the chain.
    816     GET_DYNAMIC_AREA_OFFSET,
    817 
    818     /// Generic reduction nodes. These nodes represent horizontal vector
    819     /// reduction operations, producing a scalar result.
    820     /// The STRICT variants perform reductions in sequential order. The first
    821     /// operand is an initial scalar accumulator value, and the second operand
    822     /// is the vector to reduce.
    823     VECREDUCE_STRICT_FADD, VECREDUCE_STRICT_FMUL,
    824     /// These reductions are non-strict, and have a single vector operand.
    825     VECREDUCE_FADD, VECREDUCE_FMUL,
    826     VECREDUCE_ADD, VECREDUCE_MUL,
    827     VECREDUCE_AND, VECREDUCE_OR, VECREDUCE_XOR,
    828     VECREDUCE_SMAX, VECREDUCE_SMIN, VECREDUCE_UMAX, VECREDUCE_UMIN,
    829     /// FMIN/FMAX nodes can have flags, for NaN/NoNaN variants.
    830     VECREDUCE_FMAX, VECREDUCE_FMIN,
    831 
    832     /// BUILTIN_OP_END - This must be the last enum value in this list.
    833     /// The target-specific pre-isel opcode values start here.
    834     BUILTIN_OP_END
    835   };
    836 
    837   /// FIRST_TARGET_MEMORY_OPCODE - Target-specific pre-isel operations
    838   /// which do not reference a specific memory location should be less than
    839   /// this value. Those that do must not be less than this value, and can
    840   /// be used with SelectionDAG::getMemIntrinsicNode.
    841   static const int FIRST_TARGET_MEMORY_OPCODE = BUILTIN_OP_END+300;
    842 
    843   //===--------------------------------------------------------------------===//
    844   /// MemIndexedMode enum - This enum defines the load / store indexed
    845   /// addressing modes.
    846   ///
    847   /// UNINDEXED    "Normal" load / store. The effective address is already
    848   ///              computed and is available in the base pointer. The offset
    849   ///              operand is always undefined. In addition to producing a
    850   ///              chain, an unindexed load produces one value (result of the
    851   ///              load); an unindexed store does not produce a value.
    852   ///
    853   /// PRE_INC      Similar to the unindexed mode where the effective address is
    854   /// PRE_DEC      the value of the base pointer add / subtract the offset.
    855   ///              It considers the computation as being folded into the load /
    856   ///              store operation (i.e. the load / store does the address
    857   ///              computation as well as performing the memory transaction).
    858   ///              The base operand is always undefined. In addition to
    859   ///              producing a chain, pre-indexed load produces two values
    860   ///              (result of the load and the result of the address
    861   ///              computation); a pre-indexed store produces one value (result
    862   ///              of the address computation).
    863   ///
    864   /// POST_INC     The effective address is the value of the base pointer. The
    865   /// POST_DEC     value of the offset operand is then added to / subtracted
    866   ///              from the base after memory transaction. In addition to
    867   ///              producing a chain, post-indexed load produces two values
    868   ///              (the result of the load and the result of the base +/- offset
    869   ///              computation); a post-indexed store produces one value (the
    870   ///              the result of the base +/- offset computation).
    871   enum MemIndexedMode {
    872     UNINDEXED = 0,
    873     PRE_INC,
    874     PRE_DEC,
    875     POST_INC,
    876     POST_DEC
    877   };
    878 
    879   static const int LAST_INDEXED_MODE = POST_DEC + 1;
    880 
    881   //===--------------------------------------------------------------------===//
    882   /// LoadExtType enum - This enum defines the three variants of LOADEXT
    883   /// (load with extension).
    884   ///
    885   /// SEXTLOAD loads the integer operand and sign extends it to a larger
    886   ///          integer result type.
    887   /// ZEXTLOAD loads the integer operand and zero extends it to a larger
    888   ///          integer result type.
    889   /// EXTLOAD  is used for two things: floating point extending loads and
    890   ///          integer extending loads [the top bits are undefined].
    891   enum LoadExtType {
    892     NON_EXTLOAD = 0,
    893     EXTLOAD,
    894     SEXTLOAD,
    895     ZEXTLOAD
    896   };
    897 
    898   static const int LAST_LOADEXT_TYPE = ZEXTLOAD + 1;
    899 
    900   NodeType getExtForLoadExtType(bool IsFP, LoadExtType);
    901 
    902   //===--------------------------------------------------------------------===//
    903   /// ISD::CondCode enum - These are ordered carefully to make the bitfields
    904   /// below work out, when considering SETFALSE (something that never exists
    905   /// dynamically) as 0.  "U" -> Unsigned (for integer operands) or Unordered
    906   /// (for floating point), "L" -> Less than, "G" -> Greater than, "E" -> Equal
    907   /// to.  If the "N" column is 1, the result of the comparison is undefined if
    908   /// the input is a NAN.
    909   ///
    910   /// All of these (except for the 'always folded ops') should be handled for
    911   /// floating point.  For integer, only the SETEQ,SETNE,SETLT,SETLE,SETGT,
    912   /// SETGE,SETULT,SETULE,SETUGT, and SETUGE opcodes are used.
    913   ///
    914   /// Note that these are laid out in a specific order to allow bit-twiddling
    915   /// to transform conditions.
    916   enum CondCode {
    917     // Opcode          N U L G E       Intuitive operation
    918     SETFALSE,      //    0 0 0 0       Always false (always folded)
    919     SETOEQ,        //    0 0 0 1       True if ordered and equal
    920     SETOGT,        //    0 0 1 0       True if ordered and greater than
    921     SETOGE,        //    0 0 1 1       True if ordered and greater than or equal
    922     SETOLT,        //    0 1 0 0       True if ordered and less than
    923     SETOLE,        //    0 1 0 1       True if ordered and less than or equal
    924     SETONE,        //    0 1 1 0       True if ordered and operands are unequal
    925     SETO,          //    0 1 1 1       True if ordered (no nans)
    926     SETUO,         //    1 0 0 0       True if unordered: isnan(X) | isnan(Y)
    927     SETUEQ,        //    1 0 0 1       True if unordered or equal
    928     SETUGT,        //    1 0 1 0       True if unordered or greater than
    929     SETUGE,        //    1 0 1 1       True if unordered, greater than, or equal
    930     SETULT,        //    1 1 0 0       True if unordered or less than
    931     SETULE,        //    1 1 0 1       True if unordered, less than, or equal
    932     SETUNE,        //    1 1 1 0       True if unordered or not equal
    933     SETTRUE,       //    1 1 1 1       Always true (always folded)
    934     // Don't care operations: undefined if the input is a nan.
    935     SETFALSE2,     //  1 X 0 0 0       Always false (always folded)
    936     SETEQ,         //  1 X 0 0 1       True if equal
    937     SETGT,         //  1 X 0 1 0       True if greater than
    938     SETGE,         //  1 X 0 1 1       True if greater than or equal
    939     SETLT,         //  1 X 1 0 0       True if less than
    940     SETLE,         //  1 X 1 0 1       True if less than or equal
    941     SETNE,         //  1 X 1 1 0       True if not equal
    942     SETTRUE2,      //  1 X 1 1 1       Always true (always folded)
    943 
    944     SETCC_INVALID       // Marker value.
    945   };
    946 
    947   /// Return true if this is a setcc instruction that performs a signed
    948   /// comparison when used with integer operands.
    949   inline bool isSignedIntSetCC(CondCode Code) {
    950     return Code == SETGT || Code == SETGE || Code == SETLT || Code == SETLE;
    951   }
    952 
    953   /// Return true if this is a setcc instruction that performs an unsigned
    954   /// comparison when used with integer operands.
    955   inline bool isUnsignedIntSetCC(CondCode Code) {
    956     return Code == SETUGT || Code == SETUGE || Code == SETULT || Code == SETULE;
    957   }
    958 
    959   /// Return true if the specified condition returns true if the two operands to
    960   /// the condition are equal. Note that if one of the two operands is a NaN,
    961   /// this value is meaningless.
    962   inline bool isTrueWhenEqual(CondCode Cond) {
    963     return ((int)Cond & 1) != 0;
    964   }
    965 
    966   /// This function returns 0 if the condition is always false if an operand is
    967   /// a NaN, 1 if the condition is always true if the operand is a NaN, and 2 if
    968   /// the condition is undefined if the operand is a NaN.
    969   inline unsigned getUnorderedFlavor(CondCode Cond) {
    970     return ((int)Cond >> 3) & 3;
    971   }
    972 
    973   /// Return the operation corresponding to !(X op Y), where 'op' is a valid
    974   /// SetCC operation.
    975   CondCode getSetCCInverse(CondCode Operation, bool isInteger);
    976 
    977   /// Return the operation corresponding to (Y op X) when given the operation
    978   /// for (X op Y).
    979   CondCode getSetCCSwappedOperands(CondCode Operation);
    980 
    981   /// Return the result of a logical OR between different comparisons of
    982   /// identical values: ((X op1 Y) | (X op2 Y)). This function returns
    983   /// SETCC_INVALID if it is not possible to represent the resultant comparison.
    984   CondCode getSetCCOrOperation(CondCode Op1, CondCode Op2, bool isInteger);
    985 
    986   /// Return the result of a logical AND between different comparisons of
    987   /// identical values: ((X op1 Y) & (X op2 Y)). This function returns
    988   /// SETCC_INVALID if it is not possible to represent the resultant comparison.
    989   CondCode getSetCCAndOperation(CondCode Op1, CondCode Op2, bool isInteger);
    990 
    991 } // end llvm::ISD namespace
    992 
    993 } // end llvm namespace
    994 
    995 #endif
    996