[llvm] [Utils] Avoid repeated hash lookups (NFC) (PR #129990)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/129990

None

>From 5f99ba035f87dff7f6ab017e4ba129ffbccdd9aa Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Wed, 5 Mar 2025 09:03:02 -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 c71605c500686..eb03689f31949 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -5833,9 +5833,10 @@ static bool eliminateDeadSwitchCases(SwitchInst *SI, DomTreeUpdater *DTU,
   for (const auto &Case : SI->cases()) {
     auto *Successor = Case.getCaseSuccessor();
     if (DTU) {
-      if (!NumPerSuccessorCases.count(Successor))
+      auto [It, Inserted] = NumPerSuccessorCases.try_emplace(Successor);
+      if (Inserted)
         UniqueSuccessors.push_back(Successor);
-      ++NumPerSuccessorCases[Successor];
+      ++It->second;
     }
     const APInt &CaseVal = Case.getCaseValue()->getValue();
     if (Known.Zero.intersects(CaseVal) || !Known.One.isSubsetOf(CaseVal) ||