[clang] [TableGen] Avoid repeated hash lookups (NFC) (PR #126464)

[Kazu Hirata via cfe-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/126464

None

>From 471b2f287c7b3b1ade9dbe5b1d9cb10affa0a6e6 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 9 Feb 2025 16:20:17 -0800
Subject: [PATCH] [TableGen] Avoid repeated hash lookups (NFC)

---
 clang/utils/TableGen/MveEmitter.cpp | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/clang/utils/TableGen/MveEmitter.cpp b/clang/utils/TableGen/MveEmitter.cpp
index 014b20667e03e4c..7bee2996382c115 100644
--- a/clang/utils/TableGen/MveEmitter.cpp
+++ b/clang/utils/TableGen/MveEmitter.cpp
@@ -1629,17 +1629,10 @@ void EmitterBase::EmitBuiltinCG(raw_ostream &OS) {
       for (const auto &OI : kv.second)
         key.push_back(OI.ParamValues[i]);
 
-      auto Found = ParamNumberMap.find(key);
-      if (Found != ParamNumberMap.end()) {
-        // Yes, an existing parameter variable can be reused for this.
-        ParamNumbers.push_back(Found->second);
-        continue;
-      }
-
-      // No, we need a new parameter variable.
-      int ExistingIndex = ParamNumberMap.size();
-      ParamNumberMap[key] = ExistingIndex;
-      ParamNumbers.push_back(ExistingIndex);
+      // Obtain a new parameter variable if we don't have one.
+      int ParamNum =
+          ParamNumberMap.try_emplace(key, ParamNumberMap.size()).first->second;
+      ParamNumbers.push_back(ParamNum);
     }
 
     // Now we're ready to do the pass 2 code generation, which will emit the