[llvm] [LV]Set tailfolding styles before computing feasible max VF. (PR #91403)

[via llvm-commits]

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@@ -1540,6 +1540,14 @@ class LoopVectorizationCostModel {
     }
   }
 
+  /// Disables previously chosen tail folding policy, sets it to None. Expects,
+  /// that the tail policy was selected.
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ayalz wrote:

independent of this patch: perhaps this should be setting a new policy/style - one which explicitly states there is NoTail - to fold nor unfold, rather than "disabling" and having None mean both unfolded tail and no tail.

https://github.com/llvm/llvm-project/pull/91403