[llvm] [DAGCombiner] Attempt to fold 'add' nodes to funnel-shift or rotate (PR #125612)

[Justin Fargnoli via llvm-commits]

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@@ -8340,7 +8344,7 @@ static SDValue extractShiftForRotate(SelectionDAG &DAG, SDValue OppShift,
 // The IsRotate flag should be set when the LHS of both shifts is the same.
 // Otherwise if matching a general funnel shift, it should be clear.
 static bool matchRotateSub(SDValue Pos, SDValue Neg, unsigned EltSize,
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justinfargnoli wrote:

```suggestion
static bool matchRotateSubAdd(SDValue Pos, SDValue Neg, unsigned EltSize,
```

https://github.com/llvm/llvm-project/pull/125612