[llvm] [WIP] Fold (bitwiseop X, (add (not Y), Z)) -> (bitwiseop X, (not (sub Y, Z))). (PR #141476)

[Simon Pilgrim via llvm-commits]

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@@ -11609,6 +11625,35 @@ SDValue DAGCombiner::foldShiftToAvg(SDNode *N) {
   return DAG.getNode(FloorISD, SDLoc(N), N->getValueType(0), {A, B});
 }
 
+SDValue DAGCombiner::foldBitwiseOpWithNeg(SDNode *N) {
+  if (!TLI.hasAndNot(SDValue(N, 0)))
+    return SDValue();
+
+  unsigned Opc = N->getOpcode();
+  if (Opc != ISD::AND && Opc != ISD::OR && Opc != ISD::XOR)
+    return SDValue();
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RKSimon wrote:

you can drop these and replace `m_c_BinOp(Opc, X, Y)` with `m_BitwiseLogic(X,Y)`

https://github.com/llvm/llvm-project/pull/141476