[llvm] [Analysis] Avoid repeated hash lookups (NFC) (PR #126011)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-analysis

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/126011.diff


1 Files Affected:

- (modified) llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h (+3-2) 


``````````diff
diff --git a/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h b/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
index 7a7a9594f47603d..c0b6b526cd8f4df 100644
--- a/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
+++ b/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
@@ -1143,14 +1143,15 @@ void BlockFrequencyInfoImpl<BT>::calculate(const FunctionT &F,
 template <class BT>
 void BlockFrequencyInfoImpl<BT>::setBlockFreq(const BlockT *BB,
                                               BlockFrequency Freq) {
-  if (Nodes.count(BB))
+  auto [It, Inserted] = Nodes.try_emplace(BB);
+  if (!Inserted)
     BlockFrequencyInfoImplBase::setBlockFreq(getNode(BB), Freq);
   else {
     // If BB is a newly added block after BFI is done, we need to create a new
     // BlockNode for it assigned with a new index. The index can be determined
     // by the size of Freqs.
     BlockNode NewNode(Freqs.size());
-    Nodes[BB] = {NewNode, BFICallbackVH(BB, this)};
+    It->second = {NewNode, BFICallbackVH(BB, this)};
     Freqs.emplace_back();
     BlockFrequencyInfoImplBase::setBlockFreq(NewNode, Freq);
   }

``````````

</details>


https://github.com/llvm/llvm-project/pull/126011