Commit 905abe5b authored by Leonard Chan's avatar Leonard Chan
Browse files

[Intrinsic] Signed and Unsigned Saturation Subtraction Intirnsics 

Add an intrinsic that takes 2 integers and perform saturation subtraction on
them.

This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.

Differential Revision: https://reviews.llvm.org/D53783

llvm-svn: 345512
parent 71c989ae

llvm/include/llvm/CodeGen/ISDOpcodes.h

+8 −0
Original line number Diff line number Diff line
@@ -264,6 +264,14 @@ namespace ISD { 
    /// resulting value is this minimum value.

    SADDSAT, UADDSAT,



    /// RESULT = [US]SUBSAT(LHS, RHS) - Perform saturation subtraction on 2

    /// integers with the same bit width (W). If the true value of LHS - RHS

    /// exceeds the largest value that can be represented by W bits, the

    /// resulting value is this maximum value. Otherwise, if this value is less

    /// than the smallest value that can be represented by W bits, the

    /// resulting value is this minimum value.

    SSUBSAT, USUBSAT,



    /// Simple binary floating point operators.

    FADD, FSUB, FMUL, FDIV, FREM,

llvm/include/llvm/CodeGen/TargetLowering.h

+4 −3
Original line number Diff line number Diff line
@@ -3736,9 +3736,10 @@ public: 
  SDValue getVectorElementPointer(SelectionDAG &DAG, SDValue VecPtr, EVT VecVT,

                                  SDValue Index) const;



  /// Method for building the DAG expansion of ISD::[US]ADDSAT. This method

  /// accepts integers or vectors of integers as its arguments.

  SDValue getExpandedSaturationAddition(SDNode *Node, SelectionDAG &DAG) const;

  /// Method for building the DAG expansion of ISD::[US][ADD|SUB]SAT. This

  /// method accepts integers or vectors of integers as its arguments.

  SDValue getExpandedSaturationAdditionSubtraction(SDNode *Node,

                                                   SelectionDAG &DAG) const;



  //===--------------------------------------------------------------------===//

  // Instruction Emitting Hooks

llvm/include/llvm/IR/Intrinsics.td

+6 −0
Original line number Diff line number Diff line
@@ -716,6 +716,12 @@ def int_sadd_sat : Intrinsic<[llvm_anyint_ty], 
def int_uadd_sat : Intrinsic<[llvm_anyint_ty],

                             [LLVMMatchType<0>, LLVMMatchType<0>],

                             [IntrNoMem, IntrSpeculatable, Commutative]>;

def int_ssub_sat : Intrinsic<[llvm_anyint_ty],

                             [LLVMMatchType<0>, LLVMMatchType<0>],

                             [IntrNoMem, IntrSpeculatable]>;

def int_usub_sat : Intrinsic<[llvm_anyint_ty],

                             [LLVMMatchType<0>, LLVMMatchType<0>],

                             [IntrNoMem, IntrSpeculatable]>;



//===------------------------- Memory Use Markers -------------------------===//

//

llvm/include/llvm/Target/TargetSelectionDAG.td

+2 −0
Original line number Diff line number Diff line
@@ -375,6 +375,8 @@ def umax : SDNode<"ISD::UMAX" , SDTIntBinOp, 


def saddsat    : SDNode<"ISD::SADDSAT"   , SDTIntBinOp, [SDNPCommutative]>;

def uaddsat    : SDNode<"ISD::UADDSAT"   , SDTIntBinOp, [SDNPCommutative]>;

def ssubsat    : SDNode<"ISD::SSUBSAT"   , SDTIntBinOp>;

def usubsat    : SDNode<"ISD::USUBSAT"   , SDTIntBinOp>;



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

def sext_invec : SDNode<"ISD::SIGN_EXTEND_VECTOR_INREG", SDTExtInvec>;

llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

+7 −3
Original line number Diff line number Diff line
@@ -1115,7 +1115,9 @@ void SelectionDAGLegalize::LegalizeOp(SDNode *Node) { 
                                            Node->getValueType(0));

    break;

  case ISD::SADDSAT:

  case ISD::UADDSAT: {

  case ISD::UADDSAT:

  case ISD::SSUBSAT:

  case ISD::USUBSAT: {

    Action = TLI.getOperationAction(Node->getOpcode(), Node->getValueType(0));

    break;

  }
@@ -3254,8 +3256,10 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) { 
    break;

  }

  case ISD::SADDSAT:

  case ISD::UADDSAT: {

    Results.push_back(TLI.getExpandedSaturationAddition(Node, DAG));

  case ISD::UADDSAT:

  case ISD::SSUBSAT:

  case ISD::USUBSAT: {

    Results.push_back(TLI.getExpandedSaturationAdditionSubtraction(Node, DAG));

    break;

  }

  case ISD::SADDO: