[clang] [Basic] Avoid repeated hash lookups (NFC) (PR #111467)

[Kazu Hirata via cfe-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/111467

None

>From fd6654f61025f4dc5b38a02d5c4ec3b52fe2c726 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Mon, 7 Oct 2024 07:04:14 -0700
Subject: [PATCH] [Basic] Avoid repeated hash lookups (NFC)

---
 clang/include/clang/Basic/PlistSupport.h | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/clang/include/clang/Basic/PlistSupport.h b/clang/include/clang/Basic/PlistSupport.h
index d52d196019cf84..1814130f1d2cb6 100644
--- a/clang/include/clang/Basic/PlistSupport.h
+++ b/clang/include/clang/Basic/PlistSupport.h
@@ -26,13 +26,10 @@ using FIDMap = llvm::DenseMap<FileID, unsigned>;
 
 inline unsigned AddFID(FIDMap &FIDs, SmallVectorImpl<FileID> &V,
                    FileID FID) {
-  FIDMap::iterator I = FIDs.find(FID);
-  if (I != FIDs.end())
-    return I->second;
-  unsigned NewValue = V.size();
-  FIDs[FID] = NewValue;
-  V.push_back(FID);
-  return NewValue;
+  auto [I, Inserted] = FIDs.try_emplace(FID, V.size());
+  if (Inserted)
+    V.push_back(FID);
+  return I->second;
 }
 
 inline unsigned AddFID(FIDMap &FIDs, SmallVectorImpl<FileID> &V,