[clang] [Serialization] Avoid repeated hash lookups (NFC) (PR #110950)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-modules

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/110950.diff


1 Files Affected:

- (modified) clang/lib/Serialization/GlobalModuleIndex.cpp (+7-8) 


``````````diff
diff --git a/clang/lib/Serialization/GlobalModuleIndex.cpp b/clang/lib/Serialization/GlobalModuleIndex.cpp
index 1163943c5dffaa..9c48712a0b3fbe 100644
--- a/clang/lib/Serialization/GlobalModuleIndex.cpp
+++ b/clang/lib/Serialization/GlobalModuleIndex.cpp
@@ -430,14 +430,13 @@ namespace {
 
     /// Retrieve the module file information for the given file.
     ModuleFileInfo &getModuleFileInfo(FileEntryRef File) {
-      auto Known = ModuleFiles.find(File);
-      if (Known != ModuleFiles.end())
-        return Known->second;
-
-      unsigned NewID = ModuleFiles.size();
-      ModuleFileInfo &Info = ModuleFiles[File];
-      Info.ID = NewID;
-      return Info;
+      auto [It, Inserted] = ModuleFiles.try_emplace(File);
+      if (Inserted) {
+        unsigned NewID = ModuleFiles.size();
+        ModuleFileInfo &Info = It->second;
+        Info.ID = NewID;
+      }
+      return It->second;
     }
 
   public:

``````````

</details>


https://github.com/llvm/llvm-project/pull/110950