[llvm] [LoongArch][DAG] Custom lowering for vector SETCC operations (PR #177904)

[via llvm-commits]

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@@ -725,6 +727,38 @@ SDValue LoongArchTargetLowering::lowerConstantFP(SDValue Op,
   return SDValue();
 }
 
+SDValue LoongArchTargetLowering::lowerSETCC(SDValue Op,
+                                            SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  EVT ResultVT = Op.getValueType();
+  EVT OperandVT = Op.getOperand(0).getValueType();
+
+  EVT SetCCResultVT =
+      getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), OperandVT);
+  // Check if the result type and operand type are already consistent
+  if (ResultVT == SetCCResultVT) {
+    return Op;
+  }
+
+  // Ensure operands have the same type
+  assert(Op.getOperand(0).getValueType() == Op.getOperand(1).getValueType() &&
+         "SETCC operands must have the same type!");
+
+  // Create the SETCC node with the result type derived from the operand type
+  SDValue SetCCNode =
+      DAG.getNode(ISD::SETCC, DL, SetCCResultVT, Op.getOperand(0),
+                  Op.getOperand(1), Op.getOperand(2));
+
+  // Otherwise, extend or truncate the result to match the desired result type
+  if (ResultVT.bitsGT(SetCCResultVT)) {
+    SetCCNode = DAG.getNode(ISD::ANY_EXTEND, DL, ResultVT, SetCCNode);
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woruyu wrote:

Done! modify to SIGN_EXTEND.

https://github.com/llvm/llvm-project/pull/177904