[llvm] [VPlan] Remove VPVectorPointer for part 0 after unrolling. (PR #149735)

[Mel Chen via llvm-commits]

================
@@ -1835,6 +1835,8 @@ class VPVectorPointerRecipe : public VPRecipeWithIRFlags,
                                      getGEPNoWrapFlags(), getDebugLoc());
   }
 
+  bool isPart0() { return getUnrollPart(*this) == 0; }
----------------
Mel-Chen wrote:

```suggestion
  bool isPart0() const { return getUnrollPart(*this) == 0; }
```

https://github.com/llvm/llvm-project/pull/149735