[llvm] [SLP][NFC] Redesign schedule bundle, separate from schedule data, NFC (PR #131625)

[Alexey Bataev via llvm-commits]

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@@ -4011,26 +4014,55 @@ class BoUpSLP {
   /// List of hashes of vector of loads, which are known to be non vectorizable.
   DenseSet<size_t> ListOfKnonwnNonVectorizableLoads;
 
+  class ScheduleEntity {
+    friend class ScheduleBundle;
+    friend class ScheduleData;
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alexey-bataev wrote:

Required to access getKind, which I don't want to expose

https://github.com/llvm/llvm-project/pull/131625