[llvm] [SCEV] Improve code using DenseMap::lookup (NFC) (PR #147507)

[Nikita Popov via llvm-commits]

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@@ -8494,9 +8492,8 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
         ++I;
     }
 
-    auto LoopUsersItr = LoopUsers.find(CurrL);
-    if (LoopUsersItr != LoopUsers.end())
-      llvm::append_range(ToForget, LoopUsersItr->second);
+    auto Users = LoopUsers.lookup(CurrL);
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nikic wrote:

This will copy the vector. Many similar issues below.

https://github.com/llvm/llvm-project/pull/147507