diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 12282988129..487af807ab9 100644 --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -1216,14 +1216,25 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op, APInt LoMask = APInt::getLowBitsSet(BitWidth, BitWidth - NewMask.countLeadingZeros()); if (SimplifyDemandedBits(Op.getOperand(0), LoMask, KnownZero2, - KnownOne2, TLO, Depth+1)) - return true; - if (SimplifyDemandedBits(Op.getOperand(1), LoMask, KnownZero2, - KnownOne2, TLO, Depth+1)) - return true; - // See if the operation should be performed at a smaller bit width. - if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl)) + KnownOne2, TLO, Depth+1) || + SimplifyDemandedBits(Op.getOperand(1), LoMask, KnownZero2, + KnownOne2, TLO, Depth+1) || + // See if the operation should be performed at a smaller bit width. + TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl)) { + const SDNodeFlags *Flags = Op.getNode()->getFlags(); + if (Flags->hasNoSignedWrap() || Flags->hasNoUnsignedWrap()) { + // Disable the nsw and nuw flags. We can no longer guarantee that we + // won't wrap after simplification. + SDNodeFlags NewFlags = *Flags; + NewFlags.setNoSignedWrap(false); + NewFlags.setNoUnsignedWrap(false); + SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, Op.getValueType(), + Op.getOperand(0), Op.getOperand(1), + &NewFlags); + return TLO.CombineTo(Op, NewOp); + } return true; + } LLVM_FALLTHROUGH; } default: |
