lib/Target/TargetSelectionDAG.td

//===- TargetSelectionDAG.td - Common code for DAG isels ---*- tablegen -*-===//
// 
//                     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 defines the target-independent interfaces used by SelectionDAG
// instruction selection generators.
//
//===----------------------------------------------------------------------===//

//===----------------------------------------------------------------------===//
// Selection DAG Type Constraint definitions.
//
// Note that the semantics of these constraints are hard coded into tblgen.  To
// modify or add constraints, you have to hack tblgen.
//

class SDTypeConstraint<int opnum> {
  int OperandNum = opnum;
}

// SDTCisVT - The specified operand has exactly this VT.
class SDTCisVT <int OpNum, ValueType vt> : SDTypeConstraint<OpNum> {
  ValueType VT = vt;
}

// SDTCisInt - The specified operand is has integer type.
class SDTCisInt<int OpNum> : SDTypeConstraint<OpNum>;

// SDTCisFP - The specified operand is has floating point type.
class SDTCisFP <int OpNum> : SDTypeConstraint<OpNum>;

// SDTCisSameAs - The two specified operands have identical types.
class SDTCisSameAs<int OpNum, int OtherOp> : SDTypeConstraint<OpNum> {
  int OtherOperandNum = OtherOp;
}

// SDTCisVTSmallerThanOp - The specified operand is a VT SDNode, and its type is
// smaller than the 'Other' operand.
class SDTCisVTSmallerThanOp<int OpNum, int OtherOp> : SDTypeConstraint<OpNum> {
  int OtherOperandNum = OtherOp;
}

//===----------------------------------------------------------------------===//
// Selection DAG Type Profile definitions.
//
// These use the constraints defined above to describe the type requirements of
// the various nodes.  These are not hard coded into tblgen, allowing targets to
// add their own if needed.
//

// SDTypeProfile - This profile describes the type requirements of a Selection
// DAG node.
class SDTypeProfile<int numresults, int numoperands,
                    list<SDTypeConstraint> constraints> {
  int NumResults = numresults;
  int NumOperands = numoperands;
  list<SDTypeConstraint> Constraints = constraints;
}

// Builtin profiles.
def SDTImm    : SDTypeProfile<1, 0, [SDTCisInt<0>]>;      // for 'imm'.
def SDTVT     : SDTypeProfile<1, 0, [SDTCisVT<0, OtherVT>]>; // for 'vt'
def SDTIntBinOp : SDTypeProfile<1, 2, [   // add, and, or, xor, udiv, etc.
  SDTCisSameAs<0, 1>, SDTCisSameAs<0, 2>, SDTCisInt<0>
]>;
def SDTFPBinOp : SDTypeProfile<1, 2, [      // fadd, fmul, etc.
  SDTCisSameAs<0, 1>, SDTCisSameAs<0, 2>, SDTCisFP<0>
]>;
def SDTIntUnaryOp : SDTypeProfile<1, 1, [   // ctlz
  SDTCisSameAs<0, 1>, SDTCisInt<0>
]>;
def SDTFPUnaryOp  : SDTypeProfile<1, 1, [   // fneg, fsqrt, etc
  SDTCisSameAs<0, 1>, SDTCisFP<0>
]>;
def SDTExtInreg : SDTypeProfile<1, 2, [   // sext_inreg
  SDTCisSameAs<0, 1>, SDTCisInt<0>, SDTCisVT<2, OtherVT>,
  SDTCisVTSmallerThanOp<2, 1>
]>;

//===----------------------------------------------------------------------===//
// Selection DAG Node Properties.
//
// Note: These are hard coded into tblgen.
//
class SDNodeProperty;
def SDNPCommutative : SDNodeProperty;   // X op Y == Y op X
def SDNPAssociative : SDNodeProperty;   // (X op Y) op Z == X op (Y op Z)

//===----------------------------------------------------------------------===//
// Selection DAG Node definitions.
//
class SDNode<string opcode, SDTypeProfile typeprof,
             list<SDNodeProperty> props = [], string sdclass = "SDNode"> {
  string Opcode  = opcode;
  string SDClass = sdclass;
  list<SDNodeProperty> Properties = props;
  SDTypeProfile TypeProfile = typeprof;
}

def set;
def node;

def imm        : SDNode<"ISD::Constant"  , SDTImm     , [], "ConstantSDNode">;
def vt         : SDNode<"ISD::VALUETYPE" , SDTVT      , [], "VTSDNode">;
def add        : SDNode<"ISD::ADD"       , SDTIntBinOp   ,
                        [SDNPCommutative, SDNPAssociative]>;
def sub        : SDNode<"ISD::SUB"       , SDTIntBinOp>;
def mul        : SDNode<"ISD::MUL"       , SDTIntBinOp,
                        [SDNPCommutative, SDNPAssociative]>;
def mulhs      : SDNode<"ISD::MULHS"     , SDTIntBinOp, [SDNPCommutative]>;
def mulhu      : SDNode<"ISD::MULHU"     , SDTIntBinOp, [SDNPCommutative]>;
def sdiv       : SDNode<"ISD::SDIV"      , SDTIntBinOp>;
def udiv       : SDNode<"ISD::UDIV"      , SDTIntBinOp>;
def srem       : SDNode<"ISD::SREM"      , SDTIntBinOp>;
def urem       : SDNode<"ISD::UREM"      , SDTIntBinOp>;
def srl        : SDNode<"ISD::SRL"       , SDTIntBinOp>;
def sra        : SDNode<"ISD::SRA"       , SDTIntBinOp>;
def shl        : SDNode<"ISD::SHL"       , SDTIntBinOp>;
def and        : SDNode<"ISD::AND"       , SDTIntBinOp,
                        [SDNPCommutative, SDNPAssociative]>;
def or         : SDNode<"ISD::OR"        , SDTIntBinOp,
                        [SDNPCommutative, SDNPAssociative]>;
def xor        : SDNode<"ISD::XOR"       , SDTIntBinOp,
                        [SDNPCommutative, SDNPAssociative]>;
def fadd       : SDNode<"ISD::FADD"       , SDTFPBinOp, [SDNPCommutative]>;
def fsub       : SDNode<"ISD::FSUB"       , SDTFPBinOp>;
def fmul       : SDNode<"ISD::FMUL"       , SDTFPBinOp, [SDNPCommutative]>;
def fdiv       : SDNode<"ISD::FDIV"       , SDTFPBinOp>;
def frem       : SDNode<"ISD::FREM"       , SDTFPBinOp>;
def fabs       : SDNode<"ISD::FABS"       , SDTFPUnaryOp>;
def fneg       : SDNode<"ISD::FNEG"       , SDTFPUnaryOp>;
def fsqrt      : SDNode<"ISD::FSQRT"      , SDTFPUnaryOp>;

def sext_inreg : SDNode<"ISD::SIGN_EXTEND_INREG", SDTExtInreg>;
def ctlz       : SDNode<"ISD::CTLZ"      , SDTIntUnaryOp>;

//===----------------------------------------------------------------------===//
// Selection DAG Node Transformation Functions.
//
// This mechanism allows targets to manipulate nodes in the output DAG once a
// match has been formed.  This is typically used to manipulate immediate
// values.
//
class SDNodeXForm<SDNode opc, code xformFunction> {
  SDNode Opcode = opc;
  code XFormFunction = xformFunction;
}

def NOOP_SDNodeXForm : SDNodeXForm<imm, [{}]>;


//===----------------------------------------------------------------------===//
// Selection DAG Pattern Fragments.
//
// Pattern fragments are reusable chunks of dags that match specific things.
// They can take arguments and have C++ predicates that control whether they
// match.  They are intended to make the patterns for common instructions more
// compact and readable.
//

/// PatFrag - Represents a pattern fragment.  This can match something on the
/// DAG, frame a single node to multiply nested other fragments.
///
class PatFrag<dag ops, dag frag, code pred = [{}],
              SDNodeXForm xform = NOOP_SDNodeXForm> {
  dag Operands = ops;
  dag Fragment = frag;
  code Predicate = pred;
  SDNodeXForm OperandTransform = xform;
}

// PatLeaf's are pattern fragments that have no operands.  This is just a helper
// to define immediates and other common things concisely.
class PatLeaf<dag frag, code pred = [{}], SDNodeXForm xform = NOOP_SDNodeXForm>
 : PatFrag<(ops), frag, pred, xform>;

// Leaf fragments.

def immAllOnes : PatLeaf<(imm), [{ return N->isAllOnesValue(); }]>;
def immZero    : PatLeaf<(imm), [{ return N->isNullValue();    }]>;

def vtInt      : PatLeaf<(vt),  [{ return MVT::isInteger(N->getVT()); }]>;
def vtFP       : PatLeaf<(vt),  [{ return MVT::isFloatingPoint(N->getVT()); }]>;

// Other helper fragments.

def not  : PatFrag<(ops node:$in), (xor node:$in, immAllOnes)>;
def ineg : PatFrag<(ops node:$in), (sub immZero, node:$in)>;

//===----------------------------------------------------------------------===//
// Selection DAG Pattern Support.
//
// Patterns are what are actually matched against the target-flavored
// instruction selection DAG.  Instructions defined by the target implicitly
// define patterns in most cases, but patterns can also be explicitly added when
// an operation is defined by a sequence of instructions (e.g. loading a large
// immediate value on RISC targets that do not support immediates as large as
// their GPRs).
//

class Pattern<dag patternToMatch, list<dag> resultInstrs> {
  dag       PatternToMatch = patternToMatch;
  list<dag> ResultInstrs   = resultInstrs;
}

// Pat - A simple (but common) form of a pattern, which produces a simple result
// not needing a full list.
class Pat<dag pattern, dag result> : Pattern<pattern, [result]>;