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Do not fold (add (shl x, c1), (shl c2, c1)) -> (shl (add x, c2), c1),

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we want to canonicalize the other way.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26547 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-03-05 19:52:57 +00:00
parent 5267651057
commit c1d9f1de41
1 changed files with 0 additions and 18 deletions
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18
lib/CodeGen/SelectionDAG/TargetLowering.cpp
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@ -580,24 +580,6 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
CountTrailingZeros_64(~KnownZero2)); CountTrailingZeros_64(~KnownZero2));
KnownZero = (1ULL << KnownZeroOut) - 1; KnownZero = (1ULL << KnownZeroOut) - 1;
KnownOne = 0; KnownOne = 0;
SDOperand SH = Op.getOperand(0);
// fold (add (shl x, c1), (shl c2, c1)) -> (shl (add x, c2), c1)
if (KnownZero && SH.getOpcode() == ISD::SHL && SH.Val->hasOneUse() &&
Op.Val->hasOneUse()) {
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(SH.getOperand(1))) {
MVT::ValueType VT = Op.getValueType();
unsigned ShiftAmt = SA->getValue();
uint64_t AddAmt = AA->getValue();
uint64_t AddShr = AddAmt >> ShiftAmt;
if (AddAmt == (AddShr << ShiftAmt)) {
SDOperand ADD = TLO.DAG.getNode(ISD::ADD, VT, SH.getOperand(0),
TLO.DAG.getConstant(AddShr, VT));
SDOperand SHL = TLO.DAG.getNode(ISD::SHL, VT, ADD,SH.getOperand(1));
return TLO.CombineTo(Op, SHL);
}
}
}
} }
break; break;
case ISD::SUB: case ISD::SUB: