+SDValue X86TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
+
+ MVT VT = Op.getValueType().getSimpleVT();
+
+ if (VT.isVector()) return LowerVSETCC(Op, Subtarget, DAG);
+
+ assert(VT == MVT::i8 && "SetCC type must be 8-bit integer");
+ SDValue Op0 = Op.getOperand(0);
+ SDValue Op1 = Op.getOperand(1);
+ DebugLoc dl = Op.getDebugLoc();
+ ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
+
+ // Optimize to BT if possible.
+ // Lower (X & (1 << N)) == 0 to BT(X, N).
+ // Lower ((X >>u N) & 1) != 0 to BT(X, N).
+ // Lower ((X >>s N) & 1) != 0 to BT(X, N).
+ if (Op0.getOpcode() == ISD::AND && Op0.hasOneUse() &&
+ Op1.getOpcode() == ISD::Constant &&
+ cast<ConstantSDNode>(Op1)->isNullValue() &&
+ (CC == ISD::SETEQ || CC == ISD::SETNE)) {
+ SDValue NewSetCC = LowerToBT(Op0, CC, dl, DAG);
+ if (NewSetCC.getNode())
+ return NewSetCC;
+ }
+
+ // Look for X == 0, X == 1, X != 0, or X != 1. We can simplify some forms of
+ // these.
+ if (Op1.getOpcode() == ISD::Constant &&
+ (cast<ConstantSDNode>(Op1)->getZExtValue() == 1 ||
+ cast<ConstantSDNode>(Op1)->isNullValue()) &&
+ (CC == ISD::SETEQ || CC == ISD::SETNE)) {
+
+ // If the input is a setcc, then reuse the input setcc or use a new one with
+ // the inverted condition.
+ if (Op0.getOpcode() == X86ISD::SETCC) {
+ X86::CondCode CCode = (X86::CondCode)Op0.getConstantOperandVal(0);
+ bool Invert = (CC == ISD::SETNE) ^
+ cast<ConstantSDNode>(Op1)->isNullValue();
+ if (!Invert) return Op0;
+
+ CCode = X86::GetOppositeBranchCondition(CCode);
+ return DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
+ DAG.getConstant(CCode, MVT::i8), Op0.getOperand(1));
+ }
+ }
+
+ bool isFP = Op1.getValueType().getSimpleVT().isFloatingPoint();
+ unsigned X86CC = TranslateX86CC(CC, isFP, Op0, Op1, DAG);
+ if (X86CC == X86::COND_INVALID)
+ return SDValue();
+
+ SDValue EFLAGS = EmitCmp(Op0, Op1, X86CC, DAG);
+ EFLAGS = ConvertCmpIfNecessary(EFLAGS, DAG);
+ return DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
+ DAG.getConstant(X86CC, MVT::i8), EFLAGS);
+}
+