[llvm] [CodeGen] Avoid creating instructions dealing with ones if ones aren't involved in the division (PR #99674)

[via llvm-commits]

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@@ -6628,11 +6634,14 @@ SDValue TargetLowering::BuildUDIV(SDNode *N, SelectionDAG &DAG,
     Created.push_back(Q.getNode());
   }
 
-  EVT SetCCVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
-
-  SDValue One = DAG.getConstant(1, dl, VT);
-  SDValue IsOne = DAG.getSetCC(dl, SetCCVT, N1, One, ISD::SETEQ);
-  return DAG.getSelect(dl, VT, IsOne, N0, Q);
+  if (hasAOne) {
+    EVT SetCCVT =
+        getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
+    SDValue One = DAG.getConstant(1, dl, VT);
+    SDValue IsOne = DAG.getSetCC(dl, SetCCVT, N1, One, ISD::SETEQ);
+    return DAG.getSelect(dl, VT, IsOne, N0, Q);
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AtariDreams wrote:

It doesn't always though. 

https://github.com/llvm/llvm-project/pull/99674