[clang] [CrossTU] Avoid repeated hash lookups (NFC) (PR #126380)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/126380.diff


1 Files Affected:

- (modified) clang/lib/CrossTU/CrossTranslationUnit.cpp (+3-2) 


``````````diff
diff --git a/clang/lib/CrossTU/CrossTranslationUnit.cpp b/clang/lib/CrossTU/CrossTranslationUnit.cpp
index 9faf2a8a173411b..ad2ebb6cd6e6c80 100644
--- a/clang/lib/CrossTU/CrossTranslationUnit.cpp
+++ b/clang/lib/CrossTU/CrossTranslationUnit.cpp
@@ -453,7 +453,8 @@ CrossTranslationUnitContext::ASTUnitStorage::getASTUnitForFunction(
       return std::move(IndexLoadError);
 
     // Check if there is an entry in the index for the function.
-    if (!NameFileMap.count(FunctionName)) {
+    auto It = NameFileMap.find(FunctionName);
+    if (It == NameFileMap.end()) {
       ++NumNotInOtherTU;
       return llvm::make_error<IndexError>(index_error_code::missing_definition);
     }
@@ -461,7 +462,7 @@ CrossTranslationUnitContext::ASTUnitStorage::getASTUnitForFunction(
     // Search in the index for the filename where the definition of FunctionName
     // resides.
     if (llvm::Expected<ASTUnit *> FoundForFile =
-            getASTUnitForFile(NameFileMap[FunctionName], DisplayCTUProgress)) {
+            getASTUnitForFile(It->second, DisplayCTUProgress)) {
 
       // Update the cache.
       NameASTUnitMap[FunctionName] = *FoundForFile;

``````````

</details>


https://github.com/llvm/llvm-project/pull/126380