[llvm] [TableGen] Avoid repeated hash lookps (NFC) (PR #108138)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-selectiondag

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/108138.diff


1 Files Affected:

- (modified) llvm/utils/TableGen/DAGISelMatcherEmitter.cpp (+3-3) 


``````````diff
diff --git a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
index 1b93e3d5e3b705..a14cc3d6b844c5 100644
--- a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
@@ -71,9 +71,9 @@ class MatcherTableEmitter {
   MapVector<std::string, unsigned, StringMap<unsigned>> VecPatterns;
 
   unsigned getPatternIdxFromTable(std::string &&P, std::string &&include_loc) {
-    const auto It = VecPatterns.find(P);
-    if (It == VecPatterns.end()) {
-      VecPatterns.insert(std::pair(std::move(P), VecPatterns.size()));
+    const auto [It, Inserted] =
+        VecPatterns.try_emplace(std::move(P), VecPatterns.size());
+    if (Inserted) {
       VecIncludeStrings.push_back(std::move(include_loc));
       return VecIncludeStrings.size() - 1;
     }

``````````

</details>


https://github.com/llvm/llvm-project/pull/108138