[llvm] [SelectionDAG] Add m_Neg and m_Not pattern matcher and update DAGCombiner (PR #85365)

[Matt Arsenault via llvm-commits]

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@@ -174,10 +174,18 @@ TEST_F(SelectionDAGPatternMatchTest, matchUnaryOp) {
   SDValue SExt = DAG->getNode(ISD::SIGN_EXTEND, DL, Int64VT, Op0);
   SDValue Trunc = DAG->getNode(ISD::TRUNCATE, DL, Int32VT, Op1);
 
+  SDValue Zero = DAG->getConstant(0, DL, Int32VT);
+  SDValue AllOnes = DAG->getConstant(APInt::getAllOnes(32), DL, Int32VT);
+  SDValue Neg = DAG->getNode(ISD::SUB, DL, Int32VT, Zero, Op0);
+  SDValue Not = DAG->getNode(ISD::XOR, DL, Int32VT, AllOnes, Op0);
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arsenm wrote:

There is already a DAG->getNOT helper for this 

https://github.com/llvm/llvm-project/pull/85365