[llvm] [VPlan] Introduce ExitPhi VPInstruction, use to create phi for FOR. (PR #94760)

[via llvm-commits]

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@@ -686,9 +686,13 @@ class VPBlockBase {
 class VPLiveOut : public VPUser {
   PHINode *Phi;
 
+  /// Predecessor in VPlan of this live-out. Used to as block to set the
+  /// incoming value for.
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ayalz wrote:

```suggestion
  /// Predecessor in VPlan of this live-out. Used as the block for setting the
  /// phi's incoming value.
```

https://github.com/llvm/llvm-project/pull/94760