[llvm] Value-initialize values with *Map::try_emplace (NFC) #141522

kazutakahirata · 2025-05-26T20:03:57Z

try_emplace value-initializes values, so we do not need to pass
nullptr to try_emplace when the value types are raw pointers or
std::unique_ptr.

try_emplace value-initializes values, so we do not need to pass nullptr to try_emplace when the value types are raw pointers or std::unique_ptr<T>.

llvmbot · 2025-05-26T20:04:30Z

@llvm/pr-subscribers-vectorizers
@llvm/pr-subscribers-llvm-analysis
@llvm/pr-subscribers-backend-webassembly
@llvm/pr-subscribers-llvm-binary-utilities

@llvm/pr-subscribers-llvm-ir

Author: Kazu Hirata (kazutakahirata)

Changes

try_emplace value-initializes values, so we do not need to pass
nullptr to try_emplace when the value types are raw pointers or
std::unique_ptr<T>.

Full diff: https://github.com/llvm/llvm-project/pull/141522.diff

18 Files Affected:

(modified) llvm/include/llvm/CodeGen/DebugHandlerBase.h (+2-2)
(modified) llvm/include/llvm/SandboxIR/Context.h (+1-1)
(modified) llvm/include/llvm/Transforms/Instrumentation/CFGMST.h (+2-2)
(modified) llvm/lib/Analysis/BasicAliasAnalysis.cpp (+1-1)
(modified) llvm/lib/Analysis/LoopAccessAnalysis.cpp (+1-1)
(modified) llvm/lib/Analysis/MemorySSA.cpp (+2-2)
(modified) llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (+1-1)
(modified) llvm/lib/CodeGen/MIRParser/MIParser.cpp (+2-2)
(modified) llvm/lib/IR/Constants.cpp (+1-3)
(modified) llvm/lib/Object/ELF.cpp (+1-2)
(modified) llvm/lib/SandboxIR/Context.cpp (+3-3)
(modified) llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp (+1-1)
(modified) llvm/lib/TextAPI/RecordsSlice.cpp (+3-4)
(modified) llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp (+1-1)
(modified) llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp (+1-1)
(modified) llvm/lib/Transforms/Scalar/NewGVN.cpp (+1-1)
(modified) llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp (+1-1)
(modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+1-2)

diff --git a/llvm/include/llvm/CodeGen/DebugHandlerBase.h b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
index 3da7ea5f31231..2849497f9a43e 100644
--- a/llvm/include/llvm/CodeGen/DebugHandlerBase.h
+++ b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
@@ -101,12 +101,12 @@ class DebugHandlerBase : public AsmPrinterHandler {
 
   /// Ensure that a label will be emitted before MI.
   void requestLabelBeforeInsn(const MachineInstr *MI) {
-    LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
+    LabelsBeforeInsn.try_emplace(MI);
   }
 
   /// Ensure that a label will be emitted after MI.
   void requestLabelAfterInsn(const MachineInstr *MI) {
-    LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
+    LabelsAfterInsn.try_emplace(MI);
   }
 
   virtual void beginFunctionImpl(const MachineFunction *MF) = 0;
diff --git a/llvm/include/llvm/SandboxIR/Context.h b/llvm/include/llvm/SandboxIR/Context.h
index 974b3f15968fc..a8a21b0db855e 100644
--- a/llvm/include/llvm/SandboxIR/Context.h
+++ b/llvm/include/llvm/SandboxIR/Context.h
@@ -253,7 +253,7 @@ class Context {
   Type *getType(llvm::Type *LLVMTy) {
     if (LLVMTy == nullptr)
       return nullptr;
-    auto Pair = LLVMTypeToTypeMap.insert({LLVMTy, nullptr});
+    auto Pair = LLVMTypeToTypeMap.try_emplace(LLVMTy);
     auto It = Pair.first;
     if (Pair.second)
       It->second = std::unique_ptr<Type, TypeDeleter>(new Type(LLVMTy, *this));
diff --git a/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h b/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h
index f6bf045f7de2c..6b93b6cb83b4e 100644
--- a/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h
+++ b/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h
@@ -305,13 +305,13 @@ template <class Edge, class BBInfo> class CFGMST {
     uint32_t Index = BBInfos.size();
     auto Iter = BBInfos.end();
     bool Inserted;
-    std::tie(Iter, Inserted) = BBInfos.insert(std::make_pair(Src, nullptr));
+    std::tie(Iter, Inserted) = BBInfos.try_emplace(Src);
     if (Inserted) {
       // Newly inserted, update the real info.
       Iter->second = std::make_unique<BBInfo>(Index);
       Index++;
     }
-    std::tie(Iter, Inserted) = BBInfos.insert(std::make_pair(Dest, nullptr));
+    std::tie(Iter, Inserted) = BBInfos.try_emplace(Dest);
     if (Inserted)
       // Newly inserted, update the real info.
       Iter->second = std::make_unique<BBInfo>(Index);
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 30222b87ea467..bcc9a71917aaf 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -216,7 +216,7 @@ bool EarliestEscapeAnalysis::isNotCapturedBefore(const Value *Object,
   if (!isIdentifiedFunctionLocal(Object))
     return false;
 
-  auto Iter = EarliestEscapes.insert({Object, nullptr});
+  auto Iter = EarliestEscapes.try_emplace(Object);
   if (Iter.second) {
     Instruction *EarliestCapture = FindEarliestCapture(
         Object, *const_cast<Function *>(DT.getRoot()->getParent()),
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 755a6ac317e8d..f377da3926b26 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -2979,7 +2979,7 @@ void LoopAccessInfo::print(raw_ostream &OS, unsigned Depth) const {
 }
 
 const LoopAccessInfo &LoopAccessInfoManager::getInfo(Loop &L) {
-  const auto &[It, Inserted] = LoopAccessInfoMap.insert({&L, nullptr});
+  const auto &[It, Inserted] = LoopAccessInfoMap.try_emplace(&L);
 
   if (Inserted)
     It->second =
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
index 9f8979a9043dc..ab373386da579 100644
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -1277,7 +1277,7 @@ MemorySSA::~MemorySSA() {
 }
 
 MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
-  auto Res = PerBlockAccesses.insert(std::make_pair(BB, nullptr));
+  auto Res = PerBlockAccesses.try_emplace(BB);
 
   if (Res.second)
     Res.first->second = std::make_unique<AccessList>();
@@ -1285,7 +1285,7 @@ MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
 }
 
 MemorySSA::DefsList *MemorySSA::getOrCreateDefsList(const BasicBlock *BB) {
-  auto Res = PerBlockDefs.insert(std::make_pair(BB, nullptr));
+  auto Res = PerBlockDefs.try_emplace(BB);
 
   if (Res.second)
     Res.first->second = std::make_unique<DefsList>();
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 4aaa96c81bbc1..1322973cb92de 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -4470,7 +4470,7 @@ GCMetadataPrinter *AsmPrinter::getOrCreateGCPrinter(GCStrategy &S) {
   if (!S.usesMetadata())
     return nullptr;
 
-  auto [GCPI, Inserted] = GCMetadataPrinters.insert({&S, nullptr});
+  auto [GCPI, Inserted] = GCMetadataPrinters.try_emplace(&S);
   if (!Inserted)
     return GCPI->second.get();
 
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index cbdeacda3eb87..3a364d5ff0d20 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -326,7 +326,7 @@ PerFunctionMIParsingState::PerFunctionMIParsingState(MachineFunction &MF,
 }
 
 VRegInfo &PerFunctionMIParsingState::getVRegInfo(Register Num) {
-  auto I = VRegInfos.insert(std::make_pair(Num, nullptr));
+  auto I = VRegInfos.try_emplace(Num);
   if (I.second) {
     MachineRegisterInfo &MRI = MF.getRegInfo();
     VRegInfo *Info = new (Allocator) VRegInfo;
@@ -339,7 +339,7 @@ VRegInfo &PerFunctionMIParsingState::getVRegInfo(Register Num) {
 VRegInfo &PerFunctionMIParsingState::getVRegInfoNamed(StringRef RegName) {
   assert(RegName != "" && "Expected named reg.");
 
-  auto I = VRegInfosNamed.insert(std::make_pair(RegName.str(), nullptr));
+  auto I = VRegInfosNamed.try_emplace(RegName.str());
   if (I.second) {
     VRegInfo *Info = new (Allocator) VRegInfo;
     Info->VReg = MF.getRegInfo().createIncompleteVirtualRegister(RegName);
diff --git a/llvm/lib/IR/Constants.cpp b/llvm/lib/IR/Constants.cpp
index d7c847e541052..b2087d3651143 100644
--- a/llvm/lib/IR/Constants.cpp
+++ b/llvm/lib/IR/Constants.cpp
@@ -2876,9 +2876,7 @@ Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
 
   // Do a lookup to see if we have already formed one of these.
   auto &Slot =
-      *Ty->getContext()
-           .pImpl->CDSConstants.insert(std::make_pair(Elements, nullptr))
-           .first;
+      *Ty->getContext().pImpl->CDSConstants.try_emplace(Elements).first;
 
   // The bucket can point to a linked list of different CDS's that have the same
   // body but different types.  For example, 0,0,0,1 could be a 4 element array
diff --git a/llvm/lib/Object/ELF.cpp b/llvm/lib/Object/ELF.cpp
index bf42c92a242a1..dfc8acb0e4542 100644
--- a/llvm/lib/Object/ELF.cpp
+++ b/llvm/lib/Object/ELF.cpp
@@ -965,8 +965,7 @@ ELFFile<ELFT>::getSectionAndRelocations(
       continue;
     }
     if (*DoesSectionMatch) {
-      if (SecToRelocMap.insert(std::make_pair(&Sec, (const Elf_Shdr *)nullptr))
-              .second)
+      if (SecToRelocMap.try_emplace(&Sec).second)
         continue;
     }
 
diff --git a/llvm/lib/SandboxIR/Context.cpp b/llvm/lib/SandboxIR/Context.cpp
index fe67f9ef73fb6..fe34037d7dc49 100644
--- a/llvm/lib/SandboxIR/Context.cpp
+++ b/llvm/lib/SandboxIR/Context.cpp
@@ -54,7 +54,7 @@ Value *Context::registerValue(std::unique_ptr<Value> &&VPtr) {
 }
 
 Value *Context::getOrCreateValueInternal(llvm::Value *LLVMV, llvm::User *U) {
-  auto Pair = LLVMValueToValueMap.insert({LLVMV, nullptr});
+  auto Pair = LLVMValueToValueMap.try_emplace(LLVMV);
   auto It = Pair.first;
   if (!Pair.second)
     return It->second.get();
@@ -432,7 +432,7 @@ Value *Context::getOrCreateValueInternal(llvm::Value *LLVMV, llvm::User *U) {
 }
 
 Argument *Context::getOrCreateArgument(llvm::Argument *LLVMArg) {
-  auto Pair = LLVMValueToValueMap.insert({LLVMArg, nullptr});
+  auto Pair = LLVMValueToValueMap.try_emplace(LLVMArg);
   auto It = Pair.first;
   if (Pair.second) {
     It->second = std::unique_ptr<Argument>(new Argument(LLVMArg, *this));
@@ -652,7 +652,7 @@ Module *Context::getModule(llvm::Module *LLVMM) const {
 }
 
 Module *Context::getOrCreateModule(llvm::Module *LLVMM) {
-  auto Pair = LLVMModuleToModuleMap.insert({LLVMM, nullptr});
+  auto Pair = LLVMModuleToModuleMap.try_emplace(LLVMM);
   auto It = Pair.first;
   if (!Pair.second)
     return It->second.get();
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
index 4fe1df0ab3e42..37a34573bb339 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
@@ -270,7 +270,7 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
     Function *F = UseFunc.second;
     FunctionType *Ty = CB->getFunctionType();
 
-    auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
+    auto Pair = Wrappers.try_emplace(std::make_pair(F, Ty));
     if (Pair.second)
       Pair.first->second = createWrapper(F, Ty);
 
diff --git a/llvm/lib/TextAPI/RecordsSlice.cpp b/llvm/lib/TextAPI/RecordsSlice.cpp
index 04c48eaa628ea..1500b8752115a 100644
--- a/llvm/lib/TextAPI/RecordsSlice.cpp
+++ b/llvm/lib/TextAPI/RecordsSlice.cpp
@@ -179,7 +179,7 @@ GlobalRecord *RecordsSlice::addGlobal(StringRef Name, RecordLinkage Linkage,
     Flags |= SymbolFlags::Data;
 
   Name = copyString(Name);
-  auto Result = Globals.insert({Name, nullptr});
+  auto Result = Globals.try_emplace(Name);
   if (Result.second)
     Result.first->second =
         std::make_unique<GlobalRecord>(Name, Linkage, Flags, GV, Inlined);
@@ -194,7 +194,7 @@ ObjCInterfaceRecord *RecordsSlice::addObjCInterface(StringRef Name,
                                                     RecordLinkage Linkage,
                                                     ObjCIFSymbolKind SymType) {
   Name = copyString(Name);
-  auto Result = Classes.insert({Name, nullptr});
+  auto Result = Classes.try_emplace(Name);
   if (Result.second)
     Result.first->second =
         std::make_unique<ObjCInterfaceRecord>(Name, Linkage, SymType);
@@ -228,8 +228,7 @@ ObjCCategoryRecord *RecordsSlice::addObjCCategory(StringRef ClassToExtend,
   ClassToExtend = copyString(ClassToExtend);
 
   // Add owning record first into record slice.
-  auto Result =
-      Categories.insert({std::make_pair(ClassToExtend, Category), nullptr});
+  auto Result = Categories.try_emplace(std::make_pair(ClassToExtend, Category));
   if (Result.second)
     Result.first->second =
         std::make_unique<ObjCCategoryRecord>(ClassToExtend, Category);
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 900946e9b335b..116b862228417 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -1115,7 +1115,7 @@ Instruction *InstCombinerImpl::foldAggregateConstructionIntoAggregateReuse(
   bool FoundSrcAgg = false;
   for (BasicBlock *Pred : Preds) {
     std::pair<decltype(SourceAggregates)::iterator, bool> IV =
-        SourceAggregates.insert({Pred, nullptr});
+        SourceAggregates.try_emplace(Pred);
     // Did we already evaluate this predecessor?
     if (!IV.second)
       continue;
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 6c18bc9f77297..afac49ad03ba4 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -5880,7 +5880,7 @@ void LSRInstance::RewriteForPHI(PHINode *PN, const LSRUse &LU,
       }
 
       std::pair<DenseMap<BasicBlock *, Value *>::iterator, bool> Pair =
-        Inserted.insert(std::make_pair(BB, static_cast<Value *>(nullptr)));
+          Inserted.try_emplace(BB);
       if (!Pair.second)
         PN->setIncomingValue(i, Pair.first->second);
       else {
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
index 0a0ea65a1f036..85bd8ef1f09a8 100644
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -2383,7 +2383,7 @@ void NewGVN::performCongruenceFinding(Instruction *I, const Expression *E) {
     EClass = TOPClass;
   }
   if (!EClass) {
-    auto lookupResult = ExpressionToClass.insert({E, nullptr});
+    auto lookupResult = ExpressionToClass.try_emplace(E);
 
     // If it's not in the value table, create a new congruence class.
     if (lookupResult.second) {
diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index fb5e73727b2ef..88d2eca36ca51 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -434,7 +434,7 @@ static const Loop *PickMostRelevantLoop(const Loop *A, const Loop *B,
 /// expression, according to PickMostRelevantLoop.
 const Loop *SCEVExpander::getRelevantLoop(const SCEV *S) {
   // Test whether we've already computed the most relevant loop for this SCEV.
-  auto Pair = RelevantLoops.insert(std::make_pair(S, nullptr));
+  auto Pair = RelevantLoops.try_emplace(S);
   if (!Pair.second)
     return Pair.first->second;
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index d3f15eafb0214..6c382549ee099 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1820,8 +1820,7 @@ void VPlanTransforms::truncateToMinimalBitwidths(
         if (OpSizeInBits == NewResSizeInBits)
           continue;
         assert(OpSizeInBits > NewResSizeInBits && "nothing to truncate");
-        auto [ProcessedIter, IterIsEmpty] =
-            ProcessedTruncs.insert({Op, nullptr});
+        auto [ProcessedIter, IterIsEmpty] = ProcessedTruncs.try_emplace(Op);
         VPWidenCastRecipe *NewOp =
             IterIsEmpty
                 ? new VPWidenCastRecipe(Instruction::Trunc, Op, NewResTy)

llvmbot · 2025-05-26T20:04:31Z

@llvm/pr-subscribers-debuginfo

Author: Kazu Hirata (kazutakahirata)

Changes

try_emplace value-initializes values, so we do not need to pass
nullptr to try_emplace when the value types are raw pointers or
std::unique_ptr<T>.

Full diff: https://github.com/llvm/llvm-project/pull/141522.diff

18 Files Affected:

(modified) llvm/include/llvm/CodeGen/DebugHandlerBase.h (+2-2)
(modified) llvm/include/llvm/SandboxIR/Context.h (+1-1)
(modified) llvm/include/llvm/Transforms/Instrumentation/CFGMST.h (+2-2)
(modified) llvm/lib/Analysis/BasicAliasAnalysis.cpp (+1-1)
(modified) llvm/lib/Analysis/LoopAccessAnalysis.cpp (+1-1)
(modified) llvm/lib/Analysis/MemorySSA.cpp (+2-2)
(modified) llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (+1-1)
(modified) llvm/lib/CodeGen/MIRParser/MIParser.cpp (+2-2)
(modified) llvm/lib/IR/Constants.cpp (+1-3)
(modified) llvm/lib/Object/ELF.cpp (+1-2)
(modified) llvm/lib/SandboxIR/Context.cpp (+3-3)
(modified) llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp (+1-1)
(modified) llvm/lib/TextAPI/RecordsSlice.cpp (+3-4)
(modified) llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp (+1-1)
(modified) llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp (+1-1)
(modified) llvm/lib/Transforms/Scalar/NewGVN.cpp (+1-1)
(modified) llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp (+1-1)
(modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+1-2)

diff --git a/llvm/include/llvm/CodeGen/DebugHandlerBase.h b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
index 3da7ea5f31231..2849497f9a43e 100644
--- a/llvm/include/llvm/CodeGen/DebugHandlerBase.h
+++ b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
@@ -101,12 +101,12 @@ class DebugHandlerBase : public AsmPrinterHandler {
 
   /// Ensure that a label will be emitted before MI.
   void requestLabelBeforeInsn(const MachineInstr *MI) {
-    LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
+    LabelsBeforeInsn.try_emplace(MI);
   }
 
   /// Ensure that a label will be emitted after MI.
   void requestLabelAfterInsn(const MachineInstr *MI) {
-    LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
+    LabelsAfterInsn.try_emplace(MI);
   }
 
   virtual void beginFunctionImpl(const MachineFunction *MF) = 0;
diff --git a/llvm/include/llvm/SandboxIR/Context.h b/llvm/include/llvm/SandboxIR/Context.h
index 974b3f15968fc..a8a21b0db855e 100644
--- a/llvm/include/llvm/SandboxIR/Context.h
+++ b/llvm/include/llvm/SandboxIR/Context.h
@@ -253,7 +253,7 @@ class Context {
   Type *getType(llvm::Type *LLVMTy) {
     if (LLVMTy == nullptr)
       return nullptr;
-    auto Pair = LLVMTypeToTypeMap.insert({LLVMTy, nullptr});
+    auto Pair = LLVMTypeToTypeMap.try_emplace(LLVMTy);
     auto It = Pair.first;
     if (Pair.second)
       It->second = std::unique_ptr<Type, TypeDeleter>(new Type(LLVMTy, *this));
diff --git a/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h b/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h
index f6bf045f7de2c..6b93b6cb83b4e 100644
--- a/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h
+++ b/llvm/include/llvm/Transforms/Instrumentation/CFGMST.h
@@ -305,13 +305,13 @@ template <class Edge, class BBInfo> class CFGMST {
     uint32_t Index = BBInfos.size();
     auto Iter = BBInfos.end();
     bool Inserted;
-    std::tie(Iter, Inserted) = BBInfos.insert(std::make_pair(Src, nullptr));
+    std::tie(Iter, Inserted) = BBInfos.try_emplace(Src);
     if (Inserted) {
       // Newly inserted, update the real info.
       Iter->second = std::make_unique<BBInfo>(Index);
       Index++;
     }
-    std::tie(Iter, Inserted) = BBInfos.insert(std::make_pair(Dest, nullptr));
+    std::tie(Iter, Inserted) = BBInfos.try_emplace(Dest);
     if (Inserted)
       // Newly inserted, update the real info.
       Iter->second = std::make_unique<BBInfo>(Index);
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 30222b87ea467..bcc9a71917aaf 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -216,7 +216,7 @@ bool EarliestEscapeAnalysis::isNotCapturedBefore(const Value *Object,
   if (!isIdentifiedFunctionLocal(Object))
     return false;
 
-  auto Iter = EarliestEscapes.insert({Object, nullptr});
+  auto Iter = EarliestEscapes.try_emplace(Object);
   if (Iter.second) {
     Instruction *EarliestCapture = FindEarliestCapture(
         Object, *const_cast<Function *>(DT.getRoot()->getParent()),
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 755a6ac317e8d..f377da3926b26 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -2979,7 +2979,7 @@ void LoopAccessInfo::print(raw_ostream &OS, unsigned Depth) const {
 }
 
 const LoopAccessInfo &LoopAccessInfoManager::getInfo(Loop &L) {
-  const auto &[It, Inserted] = LoopAccessInfoMap.insert({&L, nullptr});
+  const auto &[It, Inserted] = LoopAccessInfoMap.try_emplace(&L);
 
   if (Inserted)
     It->second =
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
index 9f8979a9043dc..ab373386da579 100644
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -1277,7 +1277,7 @@ MemorySSA::~MemorySSA() {
 }
 
 MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
-  auto Res = PerBlockAccesses.insert(std::make_pair(BB, nullptr));
+  auto Res = PerBlockAccesses.try_emplace(BB);
 
   if (Res.second)
     Res.first->second = std::make_unique<AccessList>();
@@ -1285,7 +1285,7 @@ MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
 }
 
 MemorySSA::DefsList *MemorySSA::getOrCreateDefsList(const BasicBlock *BB) {
-  auto Res = PerBlockDefs.insert(std::make_pair(BB, nullptr));
+  auto Res = PerBlockDefs.try_emplace(BB);
 
   if (Res.second)
     Res.first->second = std::make_unique<DefsList>();
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 4aaa96c81bbc1..1322973cb92de 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -4470,7 +4470,7 @@ GCMetadataPrinter *AsmPrinter::getOrCreateGCPrinter(GCStrategy &S) {
   if (!S.usesMetadata())
     return nullptr;
 
-  auto [GCPI, Inserted] = GCMetadataPrinters.insert({&S, nullptr});
+  auto [GCPI, Inserted] = GCMetadataPrinters.try_emplace(&S);
   if (!Inserted)
     return GCPI->second.get();
 
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index cbdeacda3eb87..3a364d5ff0d20 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -326,7 +326,7 @@ PerFunctionMIParsingState::PerFunctionMIParsingState(MachineFunction &MF,
 }
 
 VRegInfo &PerFunctionMIParsingState::getVRegInfo(Register Num) {
-  auto I = VRegInfos.insert(std::make_pair(Num, nullptr));
+  auto I = VRegInfos.try_emplace(Num);
   if (I.second) {
     MachineRegisterInfo &MRI = MF.getRegInfo();
     VRegInfo *Info = new (Allocator) VRegInfo;
@@ -339,7 +339,7 @@ VRegInfo &PerFunctionMIParsingState::getVRegInfo(Register Num) {
 VRegInfo &PerFunctionMIParsingState::getVRegInfoNamed(StringRef RegName) {
   assert(RegName != "" && "Expected named reg.");
 
-  auto I = VRegInfosNamed.insert(std::make_pair(RegName.str(), nullptr));
+  auto I = VRegInfosNamed.try_emplace(RegName.str());
   if (I.second) {
     VRegInfo *Info = new (Allocator) VRegInfo;
     Info->VReg = MF.getRegInfo().createIncompleteVirtualRegister(RegName);
diff --git a/llvm/lib/IR/Constants.cpp b/llvm/lib/IR/Constants.cpp
index d7c847e541052..b2087d3651143 100644
--- a/llvm/lib/IR/Constants.cpp
+++ b/llvm/lib/IR/Constants.cpp
@@ -2876,9 +2876,7 @@ Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
 
   // Do a lookup to see if we have already formed one of these.
   auto &Slot =
-      *Ty->getContext()
-           .pImpl->CDSConstants.insert(std::make_pair(Elements, nullptr))
-           .first;
+      *Ty->getContext().pImpl->CDSConstants.try_emplace(Elements).first;
 
   // The bucket can point to a linked list of different CDS's that have the same
   // body but different types.  For example, 0,0,0,1 could be a 4 element array
diff --git a/llvm/lib/Object/ELF.cpp b/llvm/lib/Object/ELF.cpp
index bf42c92a242a1..dfc8acb0e4542 100644
--- a/llvm/lib/Object/ELF.cpp
+++ b/llvm/lib/Object/ELF.cpp
@@ -965,8 +965,7 @@ ELFFile<ELFT>::getSectionAndRelocations(
       continue;
     }
     if (*DoesSectionMatch) {
-      if (SecToRelocMap.insert(std::make_pair(&Sec, (const Elf_Shdr *)nullptr))
-              .second)
+      if (SecToRelocMap.try_emplace(&Sec).second)
         continue;
     }
 
diff --git a/llvm/lib/SandboxIR/Context.cpp b/llvm/lib/SandboxIR/Context.cpp
index fe67f9ef73fb6..fe34037d7dc49 100644
--- a/llvm/lib/SandboxIR/Context.cpp
+++ b/llvm/lib/SandboxIR/Context.cpp
@@ -54,7 +54,7 @@ Value *Context::registerValue(std::unique_ptr<Value> &&VPtr) {
 }
 
 Value *Context::getOrCreateValueInternal(llvm::Value *LLVMV, llvm::User *U) {
-  auto Pair = LLVMValueToValueMap.insert({LLVMV, nullptr});
+  auto Pair = LLVMValueToValueMap.try_emplace(LLVMV);
   auto It = Pair.first;
   if (!Pair.second)
     return It->second.get();
@@ -432,7 +432,7 @@ Value *Context::getOrCreateValueInternal(llvm::Value *LLVMV, llvm::User *U) {
 }
 
 Argument *Context::getOrCreateArgument(llvm::Argument *LLVMArg) {
-  auto Pair = LLVMValueToValueMap.insert({LLVMArg, nullptr});
+  auto Pair = LLVMValueToValueMap.try_emplace(LLVMArg);
   auto It = Pair.first;
   if (Pair.second) {
     It->second = std::unique_ptr<Argument>(new Argument(LLVMArg, *this));
@@ -652,7 +652,7 @@ Module *Context::getModule(llvm::Module *LLVMM) const {
 }
 
 Module *Context::getOrCreateModule(llvm::Module *LLVMM) {
-  auto Pair = LLVMModuleToModuleMap.insert({LLVMM, nullptr});
+  auto Pair = LLVMModuleToModuleMap.try_emplace(LLVMM);
   auto It = Pair.first;
   if (!Pair.second)
     return It->second.get();
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
index 4fe1df0ab3e42..37a34573bb339 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
@@ -270,7 +270,7 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
     Function *F = UseFunc.second;
     FunctionType *Ty = CB->getFunctionType();
 
-    auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
+    auto Pair = Wrappers.try_emplace(std::make_pair(F, Ty));
     if (Pair.second)
       Pair.first->second = createWrapper(F, Ty);
 
diff --git a/llvm/lib/TextAPI/RecordsSlice.cpp b/llvm/lib/TextAPI/RecordsSlice.cpp
index 04c48eaa628ea..1500b8752115a 100644
--- a/llvm/lib/TextAPI/RecordsSlice.cpp
+++ b/llvm/lib/TextAPI/RecordsSlice.cpp
@@ -179,7 +179,7 @@ GlobalRecord *RecordsSlice::addGlobal(StringRef Name, RecordLinkage Linkage,
     Flags |= SymbolFlags::Data;
 
   Name = copyString(Name);
-  auto Result = Globals.insert({Name, nullptr});
+  auto Result = Globals.try_emplace(Name);
   if (Result.second)
     Result.first->second =
         std::make_unique<GlobalRecord>(Name, Linkage, Flags, GV, Inlined);
@@ -194,7 +194,7 @@ ObjCInterfaceRecord *RecordsSlice::addObjCInterface(StringRef Name,
                                                     RecordLinkage Linkage,
                                                     ObjCIFSymbolKind SymType) {
   Name = copyString(Name);
-  auto Result = Classes.insert({Name, nullptr});
+  auto Result = Classes.try_emplace(Name);
   if (Result.second)
     Result.first->second =
         std::make_unique<ObjCInterfaceRecord>(Name, Linkage, SymType);
@@ -228,8 +228,7 @@ ObjCCategoryRecord *RecordsSlice::addObjCCategory(StringRef ClassToExtend,
   ClassToExtend = copyString(ClassToExtend);
 
   // Add owning record first into record slice.
-  auto Result =
-      Categories.insert({std::make_pair(ClassToExtend, Category), nullptr});
+  auto Result = Categories.try_emplace(std::make_pair(ClassToExtend, Category));
   if (Result.second)
     Result.first->second =
         std::make_unique<ObjCCategoryRecord>(ClassToExtend, Category);
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 900946e9b335b..116b862228417 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -1115,7 +1115,7 @@ Instruction *InstCombinerImpl::foldAggregateConstructionIntoAggregateReuse(
   bool FoundSrcAgg = false;
   for (BasicBlock *Pred : Preds) {
     std::pair<decltype(SourceAggregates)::iterator, bool> IV =
-        SourceAggregates.insert({Pred, nullptr});
+        SourceAggregates.try_emplace(Pred);
     // Did we already evaluate this predecessor?
     if (!IV.second)
       continue;
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 6c18bc9f77297..afac49ad03ba4 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -5880,7 +5880,7 @@ void LSRInstance::RewriteForPHI(PHINode *PN, const LSRUse &LU,
       }
 
       std::pair<DenseMap<BasicBlock *, Value *>::iterator, bool> Pair =
-        Inserted.insert(std::make_pair(BB, static_cast<Value *>(nullptr)));
+          Inserted.try_emplace(BB);
       if (!Pair.second)
         PN->setIncomingValue(i, Pair.first->second);
       else {
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
index 0a0ea65a1f036..85bd8ef1f09a8 100644
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -2383,7 +2383,7 @@ void NewGVN::performCongruenceFinding(Instruction *I, const Expression *E) {
     EClass = TOPClass;
   }
   if (!EClass) {
-    auto lookupResult = ExpressionToClass.insert({E, nullptr});
+    auto lookupResult = ExpressionToClass.try_emplace(E);
 
     // If it's not in the value table, create a new congruence class.
     if (lookupResult.second) {
diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index fb5e73727b2ef..88d2eca36ca51 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -434,7 +434,7 @@ static const Loop *PickMostRelevantLoop(const Loop *A, const Loop *B,
 /// expression, according to PickMostRelevantLoop.
 const Loop *SCEVExpander::getRelevantLoop(const SCEV *S) {
   // Test whether we've already computed the most relevant loop for this SCEV.
-  auto Pair = RelevantLoops.insert(std::make_pair(S, nullptr));
+  auto Pair = RelevantLoops.try_emplace(S);
   if (!Pair.second)
     return Pair.first->second;
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index d3f15eafb0214..6c382549ee099 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1820,8 +1820,7 @@ void VPlanTransforms::truncateToMinimalBitwidths(
         if (OpSizeInBits == NewResSizeInBits)
           continue;
         assert(OpSizeInBits > NewResSizeInBits && "nothing to truncate");
-        auto [ProcessedIter, IterIsEmpty] =
-            ProcessedTruncs.insert({Op, nullptr});
+        auto [ProcessedIter, IterIsEmpty] = ProcessedTruncs.try_emplace(Op);
         VPWidenCastRecipe *NewOp =
             IterIsEmpty
                 ? new VPWidenCastRecipe(Instruction::Trunc, Op, NewResTy)

) try_emplace value-initializes values, so we do not need to pass nullptr to try_emplace when the value types are raw pointers or std::unique_ptr<T>.

[llvm] Value-initialize values with *Map::try_emplace (NFC)

bebd4f6

try_emplace value-initializes values, so we do not need to pass nullptr to try_emplace when the value types are raw pointers or std::unique_ptr<T>.

kazutakahirata requested a review from cyndyishida as a code owner May 26, 2025 20:03

kazutakahirata requested review from arsenm and shiltian May 26, 2025 20:03

kazutakahirata requested a review from nikic as a code owner May 26, 2025 20:03

kazutakahirata requested a review from tgymnich May 26, 2025 20:03

llvmbot added backend:WebAssembly debuginfo vectorizers llvm:instcombine llvm:ir llvm:analysis llvm:transforms llvm:binary-utilities llvm:SandboxIR labels May 26, 2025

tgymnich approved these changes May 26, 2025

View reviewed changes

kazutakahirata merged commit 89308de into llvm:main May 26, 2025
21 checks passed

kazutakahirata deleted the cleanup_20250526_try_emplace_llvm branch May 26, 2025 22:14

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