[llvm] [InstCombine] Collect users iteratively (PR #131956)

[Matt Arsenault via llvm-commits]

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@@ -270,77 +270,87 @@ class PointerReplacer {
 } // end anonymous namespace
 
 bool PointerReplacer::collectUsers() {
-  if (!collectUsersRecursive(Root))
-    return false;
+  std::stack<User *> Worklist;
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arsenm wrote:

Use SmallVector?

https://github.com/llvm/llvm-project/pull/131956