+/// CanFoldXORWithAllOnes - Test whether the XOR operand is a AllOnes vector
+/// so it can be folded inside ANDNP.
+static bool CanFoldXORWithAllOnes(const SDNode *N) {
+ EVT VT = N->getValueType(0);
+
+ // Match direct AllOnes for 128 and 256-bit vectors
+ if (ISD::isBuildVectorAllOnes(N))
+ return true;
+
+ // Look through a bit convert.
+ if (N->getOpcode() == ISD::BITCAST)
+ N = N->getOperand(0).getNode();
+
+ // Sometimes the operand may come from a insert_subvector building a 256-bit
+ // allones vector
+ SDValue V1 = N->getOperand(0);
+ SDValue V2 = N->getOperand(1);
+
+ if (VT.getSizeInBits() == 256 &&
+ N->getOpcode() == ISD::INSERT_SUBVECTOR &&
+ V1.getOpcode() == ISD::INSERT_SUBVECTOR &&
+ V1.getOperand(0).getOpcode() == ISD::UNDEF &&
+ ISD::isBuildVectorAllOnes(V1.getOperand(1).getNode()) &&
+ ISD::isBuildVectorAllOnes(V2.getNode()))
+ return true;
+
+ return false;
+}
+