[llvm] [VPlan] Introduce generic variable-length step support (PR #177114)

[Luke Lau via llvm-commits]

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@@ -3241,15 +3241,15 @@ static void fixupVFUsersForEVL(VPlan &Plan, VPValue &EVL) {
 ///
 /// vector.body:
 /// ...
-/// %EVLPhi = EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI [ %StartV, %vector.ph ],
-///                                               [ %NextEVLIV, %vector.body ]
+/// %CurrentIteration = Current-Iteration-PHI [ %StartV, %vector.ph ],
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lukel97 wrote:

Nit, could use a slightly shorter name
```suggestion
/// %CurIter = Current-Iteration-PHI [ %StartV, %vector.ph ],
```

https://github.com/llvm/llvm-project/pull/177114