[llvm] [IR] Use single map in PredIteratorCache (NFC) (PR #101950)

[Alexis Engelke via llvm-commits]

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@@ -25,52 +25,29 @@ namespace llvm {
 /// predecessor iterator queries.  This is useful for code that repeatedly
 /// wants the predecessor list for the same blocks.
 class PredIteratorCache {
-  /// BlockToPredsMap - Pointer to null-terminated list.
-  mutable DenseMap<BasicBlock *, BasicBlock **> BlockToPredsMap;
-  mutable DenseMap<BasicBlock *, unsigned> BlockToPredCountMap;
+  /// Cached list of predecessors, allocated in Memory.
+  mutable DenseMap<BasicBlock *, ArrayRef<BasicBlock *>> BlockToPredsMap;
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aengelke wrote:

No `mutable`.

https://github.com/llvm/llvm-project/pull/101950