case NVPTXISD::Suld3DV4I32Trap:
ResNode = SelectSurfaceIntrinsic(N);
break;
+ case ISD::AND:
+ case ISD::SRA:
+ case ISD::SRL:
+ // Try to select BFE
+ ResNode = SelectBFE(N);
+ break;
case ISD::ADDRSPACECAST:
ResNode = SelectAddrSpaceCast(N);
break;
return Ret;
}
+/// SelectBFE - Look for instruction sequences that can be made more efficient
+/// by using the 'bfe' (bit-field extract) PTX instruction
+SDNode *NVPTXDAGToDAGISel::SelectBFE(SDNode *N) {
+ SDValue LHS = N->getOperand(0);
+ SDValue RHS = N->getOperand(1);
+ SDValue Len;
+ SDValue Start;
+ SDValue Val;
+ bool IsSigned = false;
+
+ if (N->getOpcode() == ISD::AND) {
+ // Canonicalize the operands
+ // We want 'and %val, %mask'
+ if (isa<ConstantSDNode>(LHS) && !isa<ConstantSDNode>(RHS)) {
+ std::swap(LHS, RHS);
+ }
+
+ ConstantSDNode *Mask = dyn_cast<ConstantSDNode>(RHS);
+ if (!Mask) {
+ // We need a constant mask on the RHS of the AND
+ return NULL;
+ }
+
+ // Extract the mask bits
+ uint64_t MaskVal = Mask->getZExtValue();
+ if (!isMask_64(MaskVal)) {
+ // We *could* handle shifted masks here, but doing so would require an
+ // 'and' operation to fix up the low-order bits so we would trade
+ // shr+and for bfe+and, which has the same throughput
+ return NULL;
+ }
+
+ // How many bits are in our mask?
+ uint64_t NumBits = CountTrailingOnes_64(MaskVal);
+ Len = CurDAG->getTargetConstant(NumBits, MVT::i32);
+
+ if (LHS.getOpcode() == ISD::SRL || LHS.getOpcode() == ISD::SRA) {
+ // We have a 'srl/and' pair, extract the effective start bit and length
+ Val = LHS.getNode()->getOperand(0);
+ Start = LHS.getNode()->getOperand(1);
+ ConstantSDNode *StartConst = dyn_cast<ConstantSDNode>(Start);
+ if (StartConst) {
+ uint64_t StartVal = StartConst->getZExtValue();
+ // How many "good" bits do we have left? "good" is defined here as bits
+ // that exist in the original value, not shifted in.
+ uint64_t GoodBits = Start.getValueType().getSizeInBits() - StartVal;
+ if (NumBits > GoodBits) {
+ // Do not handle the case where bits have been shifted in. In theory
+ // we could handle this, but the cost is likely higher than just
+ // emitting the srl/and pair.
+ return NULL;
+ }
+ Start = CurDAG->getTargetConstant(StartVal, MVT::i32);
+ } else {
+ // Do not handle the case where the shift amount (can be zero if no srl
+ // was found) is not constant. We could handle this case, but it would
+ // require run-time logic that would be more expensive than just
+ // emitting the srl/and pair.
+ return NULL;
+ }
+ } else {
+ // Do not handle the case where the LHS of the and is not a shift. While
+ // it would be trivial to handle this case, it would just transform
+ // 'and' -> 'bfe', but 'and' has higher-throughput.
+ return NULL;
+ }
+ } else if (N->getOpcode() == ISD::SRL || N->getOpcode() == ISD::SRA) {
+ if (LHS->getOpcode() == ISD::AND) {
+ ConstantSDNode *ShiftCnst = dyn_cast<ConstantSDNode>(RHS);
+ if (!ShiftCnst) {
+ // Shift amount must be constant
+ return NULL;
+ }
+
+ uint64_t ShiftAmt = ShiftCnst->getZExtValue();
+
+ SDValue AndLHS = LHS->getOperand(0);
+ SDValue AndRHS = LHS->getOperand(1);
+
+ // Canonicalize the AND to have the mask on the RHS
+ if (isa<ConstantSDNode>(AndLHS)) {
+ std::swap(AndLHS, AndRHS);
+ }
+
+ ConstantSDNode *MaskCnst = dyn_cast<ConstantSDNode>(AndRHS);
+ if (!MaskCnst) {
+ // Mask must be constant
+ return NULL;
+ }
+
+ uint64_t MaskVal = MaskCnst->getZExtValue();
+ uint64_t NumZeros;
+ uint64_t NumBits;
+ if (isMask_64(MaskVal)) {
+ NumZeros = 0;
+ // The number of bits in the result bitfield will be the number of
+ // trailing ones (the AND) minus the number of bits we shift off
+ NumBits = CountTrailingOnes_64(MaskVal) - ShiftAmt;
+ } else if (isShiftedMask_64(MaskVal)) {
+ NumZeros = countTrailingZeros(MaskVal);
+ unsigned NumOnes = CountTrailingOnes_64(MaskVal >> NumZeros);
+ // The number of bits in the result bitfield will be the number of
+ // trailing zeros plus the number of set bits in the mask minus the
+ // number of bits we shift off
+ NumBits = NumZeros + NumOnes - ShiftAmt;
+ } else {
+ // This is not a mask we can handle
+ return NULL;
+ }
+
+ if (ShiftAmt < NumZeros) {
+ // Handling this case would require extra logic that would make this
+ // transformation non-profitable
+ return NULL;
+ }
+
+ Val = AndLHS;
+ Start = CurDAG->getTargetConstant(ShiftAmt, MVT::i32);
+ Len = CurDAG->getTargetConstant(NumBits, MVT::i32);
+ } else if (LHS->getOpcode() == ISD::SHL) {
+ // Here, we have a pattern like:
+ //
+ // (sra (shl val, NN), MM)
+ // or
+ // (srl (shl val, NN), MM)
+ //
+ // If MM >= NN, we can efficiently optimize this with bfe
+ Val = LHS->getOperand(0);
+
+ SDValue ShlRHS = LHS->getOperand(1);
+ ConstantSDNode *ShlCnst = dyn_cast<ConstantSDNode>(ShlRHS);
+ if (!ShlCnst) {
+ // Shift amount must be constant
+ return NULL;
+ }
+ uint64_t InnerShiftAmt = ShlCnst->getZExtValue();
+
+ SDValue ShrRHS = RHS;
+ ConstantSDNode *ShrCnst = dyn_cast<ConstantSDNode>(ShrRHS);
+ if (!ShrCnst) {
+ // Shift amount must be constant
+ return NULL;
+ }
+ uint64_t OuterShiftAmt = ShrCnst->getZExtValue();
+
+ // To avoid extra codegen and be profitable, we need Outer >= Inner
+ if (OuterShiftAmt < InnerShiftAmt) {
+ return NULL;
+ }
+
+ // If the outer shift is more than the type size, we have no bitfield to
+ // extract (since we also check that the inner shift is <= the outer shift
+ // then this also implies that the inner shift is < the type size)
+ if (OuterShiftAmt >= Val.getValueType().getSizeInBits()) {
+ return NULL;
+ }
+
+ Start =
+ CurDAG->getTargetConstant(OuterShiftAmt - InnerShiftAmt, MVT::i32);
+ Len =
+ CurDAG->getTargetConstant(Val.getValueType().getSizeInBits() -
+ OuterShiftAmt, MVT::i32);
+
+ if (N->getOpcode() == ISD::SRA) {
+ // If we have a arithmetic right shift, we need to use the signed bfe
+ // variant
+ IsSigned = true;
+ }
+ } else {
+ // No can do...
+ return NULL;
+ }
+ } else {
+ // No can do...
+ return NULL;
+ }
+
+
+ unsigned Opc;
+ // For the BFE operations we form here from "and" and "srl", always use the
+ // unsigned variants.
+ if (Val.getValueType() == MVT::i32) {
+ if (IsSigned) {
+ Opc = NVPTX::BFE_S32rii;
+ } else {
+ Opc = NVPTX::BFE_U32rii;
+ }
+ } else if (Val.getValueType() == MVT::i64) {
+ if (IsSigned) {
+ Opc = NVPTX::BFE_S64rii;
+ } else {
+ Opc = NVPTX::BFE_U64rii;
+ }
+ } else {
+ // We cannot handle this type
+ return NULL;
+ }
+
+ SDValue Ops[] = {
+ Val, Start, Len
+ };
+
+ SDNode *Ret =
+ CurDAG->getMachineNode(Opc, SDLoc(N), N->getVTList(), Ops);
+
+ return Ret;
+}
+
// SelectDirectAddr - Match a direct address for DAG.
// A direct address could be a globaladdress or externalsymbol.
bool NVPTXDAGToDAGISel::SelectDirectAddr(SDValue N, SDValue &Address) {
!strconcat("}}", ""))))))))),
[(set Int64Regs:$dst, (rotr Int64Regs:$src, Int32Regs:$amt))]>;
+// BFE - bit-field extract
+
+multiclass BFE<string TyStr, RegisterClass RC> {
+ // BFE supports both 32-bit and 64-bit values, but the start and length
+ // operands are always 32-bit
+ def rrr
+ : NVPTXInst<(outs RC:$d),
+ (ins RC:$a, Int32Regs:$b, Int32Regs:$c),
+ !strconcat("bfe.", TyStr, " \t$d, $a, $b, $c;"), []>;
+ def rri
+ : NVPTXInst<(outs RC:$d),
+ (ins RC:$a, Int32Regs:$b, i32imm:$c),
+ !strconcat("bfe.", TyStr, " \t$d, $a, $b, $c;"), []>;
+ def rii
+ : NVPTXInst<(outs RC:$d),
+ (ins RC:$a, i32imm:$b, i32imm:$c),
+ !strconcat("bfe.", TyStr, " \t$d, $a, $b, $c;"), []>;
+}
+
+defm BFE_S32 : BFE<"s32", Int32Regs>;
+defm BFE_U32 : BFE<"u32", Int32Regs>;
+defm BFE_S64 : BFE<"s64", Int64Regs>;
+defm BFE_U64 : BFE<"u64", Int64Regs>;
//-----------------------------------
// General Comparison
projects / oota-llvm.git / commitdiff