Make SimplifyDemandedBits understand BUILD_PAIR
llvm-svn: 208598
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 2f5ee0c..f98f0dd 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -848,6 +848,31 @@
}
break;
}
+ case ISD::BUILD_PAIR: {
+ EVT HalfVT = Op.getOperand(0).getValueType();
+ unsigned HalfBitWidth = HalfVT.getScalarSizeInBits();
+
+ APInt MaskLo = NewMask.getLoBits(HalfBitWidth).trunc(HalfBitWidth);
+ APInt MaskHi = NewMask.getHiBits(HalfBitWidth).trunc(HalfBitWidth);
+
+ APInt KnownZeroLo, KnownOneLo;
+ APInt KnownZeroHi, KnownOneHi;
+
+ if (SimplifyDemandedBits(Op.getOperand(0), MaskLo, KnownZeroLo,
+ KnownOneLo, TLO, Depth + 1))
+ return true;
+
+ if (SimplifyDemandedBits(Op.getOperand(1), MaskHi, KnownZeroHi,
+ KnownOneHi, TLO, Depth + 1))
+ return true;
+
+ KnownZero = KnownZeroLo.zext(BitWidth) |
+ KnownZeroHi.zext(BitWidth).shl(HalfBitWidth);
+
+ KnownOne = KnownOneLo.zext(BitWidth) |
+ KnownOneHi.zext(BitWidth).shl(HalfBitWidth);
+ break;
+ }
case ISD::ZERO_EXTEND: {
unsigned OperandBitWidth =
Op.getOperand(0).getValueType().getScalarType().getSizeInBits();