[llvm] [X86] Fold vgf2p8affineqb XOR with splat constant into immediate (PR #179103)

[Simon Pilgrim via llvm-commits]

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@@ -55844,6 +55821,59 @@ static SDValue foldXor1SetCC(SDNode *N, const SDLoc &DL, SelectionDAG &DAG) {
   return getSETCC(NewCC, LHS->getOperand(1), DL, DAG);
 }
 
+static SDValue combineXorWithGF2P8AFFINEQB(SDNode *N, SelectionDAG &DAG,
+                                           const X86Subtarget &Subtarget) {
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RKSimon wrote:

Subtarget unused?

https://github.com/llvm/llvm-project/pull/179103