[llvm] [GenericCycle] Add a Cache for getExitBlocks in GenericCycle (PR #112290)

[Matt Arsenault via llvm-commits]

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@@ -124,7 +141,12 @@ template <typename ContextT> class GenericCycle {
   bool contains(const GenericCycle *C) const;
 
   const GenericCycle *getParentCycle() const { return ParentCycle; }
-  GenericCycle *getParentCycle() { return ParentCycle; }
+
+  GenericCycle *getParentCycle() {
+    clearCache();
+    return ParentCycle;
+  }
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arsenm wrote:

Clearing the cache in a getter (and only the non-const one) seems dubious

https://github.com/llvm/llvm-project/pull/112290