[llvm] [SandboxVectorizer] Add MemSeed bundle types (PR #111584)

[via llvm-commits]

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@@ -123,5 +123,35 @@ class SeedBundle {
   }
 #endif // NDEBUG
 };
+
+template <typename LoadOrStoreT> class MemSeedBundle : public SeedBundle {
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vporpo wrote:

A brief description comment?

https://github.com/llvm/llvm-project/pull/111584