[llvm] [VPlan] Implement interleaving as VPlan-to-VPlan transform. (PR #95842)

[via llvm-commits]

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@@ -1752,7 +1758,7 @@ class VPVectorPointerRecipe : public VPRecipeWithIRFlags {
   bool onlyFirstPartUsed(const VPValue *Op) const override {
     assert(is_contained(operands(), Op) &&
            "Op must be an operand of the recipe");
-    assert(getNumOperands() == 1 && "must have a single operand");
+    assert(getNumOperands() <= 2 && "must have a single operand");
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ayalz wrote:

```suggestion
    assert(getNumOperands() <= 2 && "must have at most two operands");
```

https://github.com/llvm/llvm-project/pull/95842