[llvm] [BOLT] Avoid repeated hash lookups (NFC) (PR #140426)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-bolt

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>

We can use try_emplace to succinctly implement GetOrCreateFuncEntry
and GetOrCreateFuncMemEntry.  Since it's a bit mouthful to say
FuncBasicSampleData::ContainerTy(), this patch changes the second
parameters to default ones.


---
Full diff: https://github.com/llvm/llvm-project/pull/140426.diff


2 Files Affected:

- (modified) bolt/include/bolt/Profile/DataReader.h (+2-2) 
- (modified) bolt/lib/Profile/DataReader.cpp (+2-17) 


``````````diff
diff --git a/bolt/include/bolt/Profile/DataReader.h b/bolt/include/bolt/Profile/DataReader.h
index 80031f8f6ef4a..c91498214e62a 100644
--- a/bolt/include/bolt/Profile/DataReader.h
+++ b/bolt/include/bolt/Profile/DataReader.h
@@ -205,7 +205,7 @@ struct FuncMemData {
 
   FuncMemData() {}
 
-  FuncMemData(StringRef Name, ContainerTy Data)
+  FuncMemData(StringRef Name, ContainerTy Data = ContainerTy())
       : Name(Name), Data(std::move(Data)) {}
 };
 
@@ -241,7 +241,7 @@ struct FuncBasicSampleData {
   StringRef Name;
   ContainerTy Data;
 
-  FuncBasicSampleData(StringRef Name, ContainerTy Data)
+  FuncBasicSampleData(StringRef Name, ContainerTy Data = ContainerTy())
       : Name(Name), Data(std::move(Data)) {}
 
   /// Get the number of samples recorded in [Start, End)
diff --git a/bolt/lib/Profile/DataReader.cpp b/bolt/lib/Profile/DataReader.cpp
index 198f7d8642738..079cdc1785eaf 100644
--- a/bolt/lib/Profile/DataReader.cpp
+++ b/bolt/lib/Profile/DataReader.cpp
@@ -1088,26 +1088,11 @@ bool DataReader::hasMemData() {
 
 std::error_code DataReader::parseInNoLBRMode() {
   auto GetOrCreateFuncEntry = [&](StringRef Name) {
-    auto I = NamesToBasicSamples.find(Name);
-    if (I == NamesToBasicSamples.end()) {
-      bool Success;
-      std::tie(I, Success) = NamesToBasicSamples.insert(std::make_pair(
-          Name, FuncBasicSampleData(Name, FuncBasicSampleData::ContainerTy())));
-
-      assert(Success && "unexpected result of insert");
-    }
-    return I;
+    return NamesToBasicSamples.try_emplace(Name, Name).first;
   };
 
   auto GetOrCreateFuncMemEntry = [&](StringRef Name) {
-    auto I = NamesToMemEvents.find(Name);
-    if (I == NamesToMemEvents.end()) {
-      bool Success;
-      std::tie(I, Success) = NamesToMemEvents.insert(
-          std::make_pair(Name, FuncMemData(Name, FuncMemData::ContainerTy())));
-      assert(Success && "unexpected result of insert");
-    }
-    return I;
+    return NamesToMemEvents.try_emplace(Name, Name).first;
   };
 
   while (hasBranchData()) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/140426