diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/TargetLowering.cpp | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 49b0f1b..819e640 100644 --- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -1765,17 +1765,16 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op, break; } case ISD::AssertZext: { - // Demand all the bits of the input that are demanded in the output. - // The low bits are obvious; the high bits are demanded because we're - // asserting that they're zero here. - if (SimplifyDemandedBits(Op.getOperand(0), NewMask, + // AssertZext demands all of the high bits, plus any of the low bits + // demanded by its users. + EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT(); + APInt InMask = APInt::getLowBitsSet(BitWidth, + VT.getSizeInBits()); + if (SimplifyDemandedBits(Op.getOperand(0), ~InMask | NewMask, KnownZero, KnownOne, TLO, Depth+1)) return true; assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); - EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT(); - APInt InMask = APInt::getLowBitsSet(BitWidth, - VT.getSizeInBits()); KnownZero |= ~InMask & NewMask; break; } |