[llvm] [LV][RFC] Generating conditional VPBB that will be skip when the mask is inactive in VPlan. (PR #141900)

[Philip Reames via llvm-commits]

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@@ -2202,6 +2219,8 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
   for (VPValue *HeaderMask : collectAllHeaderMasks(Plan)) {
     for (VPUser *U : collectUsersRecursively(HeaderMask)) {
       auto *CurRecipe = cast<VPRecipeBase>(U);
+      if (replaceHeaderMaskToEVL(HeaderMask, CurRecipe))
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preames wrote:

JFYI, this line is unsound.  The next line can return *without* replacing a a recipe with a VL recipe, and thus you've just dropped a mask without adding any form of predication.

https://github.com/llvm/llvm-project/pull/141900