[llvm] [Utils] Avoid repeated hash lookups (NFC) (PR #130464)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/130464.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Utils/SimplifyCFG.cpp (+3-2) 


``````````diff
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index eb03689f31949..833dc7331aecd 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -6883,9 +6883,10 @@ static bool switchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
     for (const auto &I : Results) {
       PHINode *PHI = I.first;
       Constant *Value = I.second;
-      if (!ResultLists.count(PHI))
+      auto [It, Inserted] = ResultLists.try_emplace(PHI);
+      if (Inserted)
         PHIs.push_back(PHI);
-      ResultLists[PHI].push_back(std::make_pair(CaseVal, Value));
+      It->second.push_back(std::make_pair(CaseVal, Value));
     }
   }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/130464