[llvm] [LV][NFC]Preselect folding style before choosing maxing VF, NFC. (PR #81885)

[Florian Hahn via llvm-commits]

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@@ -4632,10 +4644,9 @@ LoopVectorizationCostModel::computeMaxVF(ElementCount UserVF, unsigned UserIC) {
   // found modulo the vectorization factor is not zero, try to fold the tail
   // by masking.
   // FIXME: look for a smaller MaxVF that does divide TC rather than masking.
-  if (Legal->prepareToFoldTailByMasking()) {
-    CanFoldTailByMasking = true;
+  selectTailFoldinStyle();
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fhahn wrote:

Thanks for checking! Most of those should be due to setting styles if `ScalarEpilogueStatus == CM_ScalarEpilogueAllowed`, but there are a few other cases that cannot really be handled nicely for now, so best to just move the code in this patch.

https://github.com/llvm/llvm-project/pull/81885