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

[Kazu Hirata via llvm-commits]

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

None

>From 3768547ee612af3234254649f905f2af7d5761cf Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sat, 8 Mar 2025 01:06:14 -0800
Subject: [PATCH] [Utils] Avoid repeated hash lookups (NFC)

---
 llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

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));
     }
   }