[llvm] [PowerPC] Add custom lowering for SADD overflow for i32 and i64 (PR #159255)

[via llvm-commits]

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@@ -12614,6 +12617,31 @@ SDValue PPCTargetLowering::LowerSSUBO(SDValue Op, SelectionDAG &DAG) const {
   return DAG.getMergeValues({Sub, OverflowTrunc}, dl);
 }
 
+SDValue PPCTargetLowering::LowerSADDO(SDValue Op, SelectionDAG &DAG) const {
+
+  SDLoc dl(Op);
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  EVT VT = Op.getNode()->getValueType(0);
+
+  SDValue Add = DAG.getNode(ISD::ADD, dl, VT, LHS, RHS);
+
+  SDValue Xor1 = DAG.getNode(ISD::XOR, dl, VT, LHS, RHS);
+  SDValue NotXor1 = DAG.getNOT(dl, Xor1, VT);
+  SDValue Xor2 = DAG.getNode(ISD::XOR, dl, VT, Add, LHS);
+
+  SDValue And = DAG.getNode(ISD::AND, dl, VT, NotXor1, Xor2);
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RolandF77 wrote:

SDValue OverflowInSign

https://github.com/llvm/llvm-project/pull/159255