[llvm] [VPlan] Introduce VPlan-based hasTailFolded helper. (NFC) (PR #208329)

[Florian Hahn via llvm-commits]

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@@ -7126,6 +7125,13 @@ bool LoopVectorizationPlanner::requiresScalarEpilogue(VPlan &Plan,
   return Result;
 }
 
+bool LoopVectorizationPlanner::hasTailFolded(const VPlan &Plan) const {
+  bool Result = Plan.hasTailFolded();
+  assert(CM.foldTailByMasking() == Result &&
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fhahn wrote:

Yes I plan to remove it soon, as mentioned in the PR description. This is just an extra guard to make sure nothing is missed

>  The wrapper should be removed after no divergence are found.

https://github.com/llvm/llvm-project/pull/208329