The previous implementation of `combineOp_VLToVWOp_VL` manually replaced
old
nodes with newly created widened nodes, but only added the new node
itself to
the `DAGCombiner` worklist. Since the users of the new node were not
added,
some combine opportunities could be missed when external `DAGCombiner`
passes
expected those users to be reconsidered.
This patch replaces the custom replacement logic with a call to
`DCI.CombineTo()`, which performs node replacement in a way consistent
with
`DAGCombiner::Run`:
- Replace all uses of the old node.
- Add the new node and its users to the worklist.
- Clean up unused nodes when appropriate.
Using `CombineTo` ensures that `combineOp_VLToVWOp_VL` behaves
consistently with
the standard `DAGCombiner` update model, avoiding discrepancies between
the
private worklist inside this routine and the global worklist managed by
the
combiner.
This resolves missed combine cases involving VL -> VW operator widening.
---------
Co-authored-by: Kai Lin <omg_link@qq.com>
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