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[DAGCombiner] Factor duplicated rotate code into a separate function 

No functional change intended.

llvm-svn: 198768
This commit is contained in:
Richard Sandiford 2014-01-08 15:40:47 +00:00
parent 86d305c779
commit 95c864d9bd
1 changed files with 70 additions and 66 deletions
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136
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -280,6 +280,10 @@ namespace {
SDValue MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1,
bool DemandHighBits = true);
SDValue MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1);
SDNode *MatchRotatePosNeg(SDValue Shifted, SDValue Pos, SDValue Neg,
SDValue InnerPos, SDValue InnerNeg,
unsigned PosOpcode, unsigned NegOpcode,
SDLoc DL);
SDNode *MatchRotate(SDValue LHS, SDValue RHS, SDLoc DL);
SDValue ReduceLoadWidth(SDNode *N);
SDValue ReduceLoadOpStoreWidth(SDNode *N);
@ -3302,6 +3306,63 @@ static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) {
return false;
}
// A subroutine of MatchRotate used once we have found an OR of two opposite
// shifts of Shifted. If Neg == <operand size> - Pos then the OR reduces
// to both (PosOpcode Shifted, Pos) and (NegOpcode Shifted, Neg), with the
// former being preferred if supported. InnerPos and InnerNeg are Pos and
// Neg with outer conversions stripped away.
SDNode *DAGCombiner::MatchRotatePosNeg(SDValue Shifted, SDValue Pos,
SDValue Neg, SDValue InnerPos,
SDValue InnerNeg, unsigned PosOpcode,
unsigned NegOpcode, SDLoc DL) {
// Check that Neg == SUBC - Pos.
if (InnerNeg.getOpcode() != ISD::SUB)
return 0;
ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(InnerNeg.getOperand(0));
if (!SUBC)
return 0;
if (InnerNeg.getOperand(1) != InnerPos)
return 0;
// fold (or (shl x, (*ext y)),
// (srl x, (*ext (sub 32, y)))) ->
// (rotl x, y) or (rotr x, (sub 32, y))
//
// fold (or (shl x, (*ext (sub 32, y))),
// (srl x, (*ext y))) ->
// (rotr x, y) or (rotl x, (sub 32, y))
EVT VT = Shifted.getValueType();
unsigned OpSizeInBits = VT.getSizeInBits();
if (SUBC->getAPIntValue() == OpSizeInBits) {
bool HasPos = TLI.isOperationLegalOrCustom(PosOpcode, VT);
return DAG.getNode(HasPos ? PosOpcode : NegOpcode, DL, VT, Shifted,
HasPos ? Pos : Neg).getNode();
}
// fold (or (shl (*ext x), (*ext y)),
// (srl (*ext x), (*ext (sub 32, y)))) ->
// (*ext (rotl x, y)) or (*ext (rotr x, (sub 32, y)))
//
// fold (or (shl (*ext x), (*ext (sub 32, y))),
// (srl (*ext x), (*ext y))) ->
// (*ext (rotr x, y)) or (*ext (rotl x, (sub 32, y)))
if (Shifted.getOpcode() == ISD::ZERO_EXTEND ||
Shifted.getOpcode() == ISD::ANY_EXTEND) {
SDValue InnerShifted = Shifted.getOperand(0);
EVT InnerVT = InnerShifted.getValueType();
bool HasPosInner = TLI.isOperationLegalOrCustom(PosOpcode, InnerVT);
if (HasPosInner || TLI.isOperationLegalOrCustom(NegOpcode, InnerVT)) {
if (InnerVT.getSizeInBits() == SUBC->getAPIntValue()) {
SDValue V = DAG.getNode(HasPosInner ? PosOpcode : NegOpcode, DL,
InnerVT, InnerShifted, HasPosInner ? Pos : Neg);
return DAG.getNode(Shifted.getOpcode(), DL, VT, V).getNode();
}
}
}
return 0;
}
// MatchRotate - Handle an 'or' of two operands. If this is one of the many
// idioms for rotate, and if the target supports rotation instructions, generate
// a rot[lr].
@ -3396,72 +3457,15 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, SDLoc DL) {
RExtOp0 = RHSShiftAmt.getOperand(0);
}
if (RExtOp0.getOpcode() == ISD::SUB && RExtOp0.getOperand(1) == LExtOp0) {
// fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
// (rotl x, y)
// fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
// (rotr x, (sub 32, y))
if (ConstantSDNode *SUBC =
dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) {
if (SUBC->getAPIntValue() == OpSizeInBits) {
return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT, LHSShiftArg,
HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode();
} else if (LHSShiftArg.getOpcode() == ISD::ZERO_EXTEND ||
LHSShiftArg.getOpcode() == ISD::ANY_EXTEND) {
// fold (or (shl (*ext x), (*ext y)),
// (srl (*ext x), (*ext (sub 32, y)))) ->
// (*ext (rotl x, y))
// fold (or (shl (*ext x), (*ext y)),
// (srl (*ext x), (*ext (sub 32, y)))) ->
// (*ext (rotr x, (sub 32, y)))
SDValue LArgExtOp0 = LHSShiftArg.getOperand(0);
EVT LArgVT = LArgExtOp0.getValueType();
bool HasROTRWithLArg = TLI.isOperationLegalOrCustom(ISD::ROTR, LArgVT);
bool HasROTLWithLArg = TLI.isOperationLegalOrCustom(ISD::ROTL, LArgVT);
if (HasROTRWithLArg || HasROTLWithLArg) {
if (LArgVT.getSizeInBits() == SUBC->getAPIntValue()) {
SDValue V =
DAG.getNode(HasROTLWithLArg ? ISD::ROTL : ISD::ROTR, DL, LArgVT,
LArgExtOp0, HasROTL ? LHSShiftAmt : RHSShiftAmt);
return DAG.getNode(LHSShiftArg.getOpcode(), DL, VT, V).getNode();
}
}
}
}
} else if (LExtOp0.getOpcode() == ISD::SUB &&
RExtOp0 == LExtOp0.getOperand(1)) {
// fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
// (rotr x, y)
// fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
// (rotl x, (sub 32, y))
if (ConstantSDNode *SUBC =
dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) {
if (SUBC->getAPIntValue() == OpSizeInBits) {
return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT, LHSShiftArg,
HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode();
} else if (RHSShiftArg.getOpcode() == ISD::ZERO_EXTEND ||
RHSShiftArg.getOpcode() == ISD::ANY_EXTEND) {
// fold (or (shl (*ext x), (*ext (sub 32, y))),
// (srl (*ext x), (*ext y))) ->
// (*ext (rotl x, y))
// fold (or (shl (*ext x), (*ext (sub 32, y))),
// (srl (*ext x), (*ext y))) ->
// (*ext (rotr x, (sub 32, y)))
SDValue RArgExtOp0 = RHSShiftArg.getOperand(0);
EVT RArgVT = RArgExtOp0.getValueType();
bool HasROTRWithRArg = TLI.isOperationLegalOrCustom(ISD::ROTR, RArgVT);
bool HasROTLWithRArg = TLI.isOperationLegalOrCustom(ISD::ROTL, RArgVT);
if (HasROTRWithRArg || HasROTLWithRArg) {
if (RArgVT.getSizeInBits() == SUBC->getAPIntValue()) {
SDValue V =
DAG.getNode(HasROTRWithRArg ? ISD::ROTR : ISD::ROTL, DL, RArgVT,
RArgExtOp0, HasROTR ? RHSShiftAmt : LHSShiftAmt);
return DAG.getNode(RHSShiftArg.getOpcode(), DL, VT, V).getNode();
}
}
}
}
}
SDNode *TryL = MatchRotatePosNeg(LHSShiftArg, LHSShiftAmt, RHSShiftAmt,
LExtOp0, RExtOp0, ISD::ROTL, ISD::ROTR, DL);
if (TryL)
return TryL;
SDNode *TryR = MatchRotatePosNeg(RHSShiftArg, RHSShiftAmt, LHSShiftAmt,
RExtOp0, LExtOp0, ISD::ROTR, ISD::ROTL, DL);
if (TryR)
return TryR;
return 0;
}