[llvm] [SelectionDAG] Legalize non-divisible scalable vector widening (PR #218777)

[Paul Walker via llvm-commits]

================
@@ -9242,6 +9242,32 @@ SDValue DAGTypeLegalizer::ModifyToType(SDValue InOp, EVT NVT,
   if (InEC.hasKnownScalarFactor(WidenEC))
     return DAG.getExtractSubvector(dl, NVT, InOp, 0);
 
+  if (InVT.isScalableVector()) {
+    // Split the input and widened vector into the largest equal-sized scalable
----------------
paulwalker-arm wrote:

```suggestion
    // Split the input vector into the largest equal-sized scalable
```
or rather, I just didn't understand what the "and widened" part means?

https://github.com/llvm/llvm-project/pull/218777