[llvm] [VPlan] Add VPIRBasicBlock, use to model pre-preheader. (PR #93398)

[via llvm-commits]

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@@ -2837,6 +2837,10 @@ class VPBasicBlock : public VPBlockBase {
   /// The VPRecipes held in the order of output instructions to generate.
   RecipeListTy Recipes;
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ayalz wrote:

Yeah, Recipes can be made protected, now that a subclass may want to access them.

https://github.com/llvm/llvm-project/pull/93398