path: root/include/llvm/CodeGen/SelectionDAGNodes.h

//===-- llvm/CodeGen/SelectionDAGNodes.h - SelectionDAG Nodes ---*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the SDNode class and derived classes, which are used to
// represent the nodes and operations present in a SelectionDAG.  These nodes
// and operations are machine code level operations, with some similarities to
// the GCC RTL representation.
//
// Clients should include the SelectionDAG.h file instead of this file directly.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_SELECTIONDAGNODES_H
#define LLVM_CODEGEN_SELECTIONDAGNODES_H

#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/Value.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/iterator"
#include "llvm/Support/DataTypes.h"
#include <cassert>
#include <vector>

namespace llvm {

class SelectionDAG;
class GlobalValue;
class MachineBasicBlock;
class SDNode;
template <typename T> struct simplify_type;

/// ISD namespace - This namespace contains an enum which represents all of the
/// SelectionDAG node types and value types.
///
namespace ISD {
  //===--------------------------------------------------------------------===//
  /// ISD::NodeType enum - This enum defines all of the operators valid in a
  /// SelectionDAG.
  ///
  enum NodeType {
    // EntryToken - This is the marker used to indicate the start of the region.
    EntryToken,

    // Token factor - This node takes multiple tokens as input and produces a
    // single token result.  This is used to represent the fact that the operand
    // operators are independent of each other.
    TokenFactor,
    
    // AssertSext, AssertZext - These nodes record if a register contains a 
    // value that has already been zero or sign extended from a narrower type.  
    // These nodes take two operands.  The first is the node that has already 
    // been extended, and the second is a value type node indicating the width
    // of the extension
    AssertSext, AssertZext,

    // Various leaf nodes.
    Constant, ConstantFP, GlobalAddress, FrameIndex, ConstantPool,
    BasicBlock, ExternalSymbol, VALUETYPE, CONDCODE, Register,
    
    // TargetConstant - Like Constant, but the DAG does not do any folding or
    // simplification of the constant.  This is used by the DAG->DAG selector.
    TargetConstant,
    
    // TargetGlobalAddress - Like GlobalAddress, but the DAG does no folding or
    // anything else with this node, and this is valid in the target-specific
    // dag, turning into a GlobalAddress operand.
    TargetGlobalAddress,
    TargetFrameIndex,
    TargetConstantPool,

    // CopyToReg - This node has three operands: a chain, a register number to
    // set to this value, and a value.  
    CopyToReg,

    // CopyFromReg - This node indicates that the input value is a virtual or
    // physical register that is defined outside of the scope of this
    // SelectionDAG.  The register is available from the RegSDNode object.
    CopyFromReg,

    // ImplicitDef - This node indicates that the specified register is
    // implicitly defined by some operation (e.g. its a live-in argument).  The
    // two operands to this are the token chain coming in and the register.
    // The only result is the token chain going out.
    ImplicitDef,

    // UNDEF - An undefined node
    UNDEF,

    // EXTRACT_ELEMENT - This is used to get the first or second (determined by
    // a Constant, which is required to be operand #1), element of the aggregate
    // value specified as operand #0.  This is only for use before legalization,
    // for values that will be broken into multiple registers.
    EXTRACT_ELEMENT,

    // BUILD_PAIR - This is the opposite of EXTRACT_ELEMENT in some ways.  Given
    // two values of the same integer value type, this produces a value twice as
    // big.  Like EXTRACT_ELEMENT, this can only be used before legalization.
    BUILD_PAIR,


    // Simple binary arithmetic operators.
    ADD, SUB, MUL, SDIV, UDIV, SREM, UREM,

    // MULHU/MULHS - Multiply high - Multiply two integers of type iN, producing
    // an unsigned/signed value of type i[2*n], then return the top part.
    MULHU, MULHS,

    // Bitwise operators.
    AND, OR, XOR, SHL, SRA, SRL,

    // Counting operators
    CTTZ, CTLZ, CTPOP,

    // Select
    SELECT, 
    
    // Select with condition operator - This selects between a true value and 
    // a false value (ops #2 and #3) based on the boolean result of comparing
    // the lhs and rhs (ops #0 and #1) of a conditional expression with the 
    // condition code in op #4, a CondCodeSDNode.
    SELECT_CC,

    // SetCC operator - This evaluates to a boolean (i1) true value if the
    // condition is true.  The operands to this are the left and right operands
    // to compare (ops #0, and #1) and the condition code to compare them with
    // (op #2) as a CondCodeSDNode.
    SETCC,

    // ADD_PARTS/SUB_PARTS - These operators take two logical operands which are
    // broken into a multiple pieces each, and return the resulting pieces of
    // doing an atomic add/sub operation.  This is used to handle add/sub of
    // expanded types.  The operation ordering is:
    //       [Lo,Hi] = op [LoLHS,HiLHS], [LoRHS,HiRHS]
    ADD_PARTS, SUB_PARTS,

    // SHL_PARTS/SRA_PARTS/SRL_PARTS - These operators are used for expanded
    // integer shift operations, just like ADD/SUB_PARTS.  The operation
    // ordering is:
    //       [Lo,Hi] = op [LoLHS,HiLHS], Amt
    SHL_PARTS, SRA_PARTS, SRL_PARTS,

    // Conversion operators.  These are all single input single output
    // operations.  For all of these, the result type must be strictly
    // wider or narrower (depending on the operation) than the source
    // type.

    // SIGN_EXTEND - Used for integer types, replicating the sign bit
    // into new bits.
    SIGN_EXTEND,

    // ZERO_EXTEND - Used for integer types, zeroing the new bits.
    ZERO_EXTEND,

    // ANY_EXTEND - Used for integer types.  The high bits are undefined.
    ANY_EXTEND,
    
    // TRUNCATE - Completely drop the high bits.
    TRUNCATE,

    // [SU]INT_TO_FP - These operators convert integers (whose interpreted sign
    // depends on the first letter) to floating point.
    SINT_TO_FP,
    UINT_TO_FP,

    // SIGN_EXTEND_INREG - This operator atomically performs a SHL/SRA pair to
    // sign extend a small value in a large integer register (e.g. sign
    // extending the low 8 bits of a 32-bit register to fill the top 24 bits
    // with the 7th bit).  The size of the smaller type is indicated by the 1th
    // operand, a ValueType node.
    SIGN_EXTEND_INREG,

    // FP_TO_[US]INT - Convert a floating point value to a signed or unsigned
    // integer.
    FP_TO_SINT,
    FP_TO_UINT,

    // FP_ROUND - Perform a rounding operation from the current
    // precision down to the specified precision (currently always 64->32).
    FP_ROUND,

    // FP_ROUND_INREG - This operator takes a floating point register, and
    // rounds it to a floating point value.  It then promotes it and returns it
    // in a register of the same size.  This operation effectively just discards
    // excess precision.  The type to round down to is specified by the 1th
    // operation, a VTSDNode (currently always 64->32->64).
    FP_ROUND_INREG,

    // FP_EXTEND - Extend a smaller FP type into a larger FP type.
    FP_EXTEND,

    // FNEG, FABS, FSQRT, FSIN, FCOS - Perform unary floating point negation,
    // absolute value, square root, sine and cosine operations.
    FNEG, FABS, FSQRT, FSIN, FCOS,

    // Other operators.  LOAD and STORE have token chains as their first
    // operand, then the same operands as an LLVM load/store instruction, then a
    // SRCVALUE node that provides alias analysis information.
    LOAD, STORE,

    // EXTLOAD, SEXTLOAD, ZEXTLOAD - These three operators all load a value from
    // memory and extend them to a larger value (e.g. load a byte into a word
    // register).  All three of these have four operands, a token chain, a
    // pointer to load from, a SRCVALUE for alias analysis, and a VALUETYPE node
    // indicating the type to load.
    //
    // SEXTLOAD loads the integer operand and sign extends it to a larger
    //          integer result type.
    // ZEXTLOAD loads the integer operand and zero extends it to a larger
    //          integer result type.
    // EXTLOAD  is used for two things: floating point extending loads, and
    //          integer extending loads where it doesn't matter what the high
    //          bits are set to.  The code generator is allowed to codegen this
    //          into whichever operation is more efficient.
    EXTLOAD, SEXTLOAD, ZEXTLOAD,

    // TRUNCSTORE - This operators truncates (for integer) or rounds (for FP) a
    // value and stores it to memory in one operation.  This can be used for
    // either integer or floating point operands.  The first four operands of
    // this are the same as a standard store.  The fifth is the ValueType to
    // store it as (which will be smaller than the source value).
    TRUNCSTORE,

    // DYNAMIC_STACKALLOC - Allocate some number of bytes on the stack aligned
    // to a specified boundary.  The first operand is the token chain, the
    // second is the number of bytes to allocate, and the third is the a