[llvm] Use *Map::try_emplace (NFC) (#141190)

try_emplace can default-construct values, so we do not need to do so
on our own.  Plus, try_emplace(Key) is much simpler/shorter than
insert({Key, LongValueType()}).

Author: kazutakahirata

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -8371,7 +8371,7 @@ ScalarEvolution::getPredicatedBackedgeTakenInfo(const Loop *L) {
   if (BTI.hasFullInfo())
     return BTI;
 
-  auto Pair = PredicatedBackedgeTakenCounts.insert({L, BackedgeTakenInfo()});
+  auto Pair = PredicatedBackedgeTakenCounts.try_emplace(L);
 
   if (!Pair.second)
     return Pair.first->second;
@@ -8390,7 +8390,7 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
   // code elsewhere that it shouldn't attempt to request a new
   // backedge-taken count, which could result in infinite recursion.
   std::pair<DenseMap<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
-      BackedgeTakenCounts.insert({L, BackedgeTakenInfo()});
+      BackedgeTakenCounts.try_emplace(L);
   if (!Pair.second)
     return Pair.first->second;
 

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -234,7 +234,7 @@ unsigned CodeViewDebug::maybeRecordFile(const DIFile *F) {
 CodeViewDebug::InlineSite &
 CodeViewDebug::getInlineSite(const DILocation *InlinedAt,
                              const DISubprogram *Inlinee) {
-  auto SiteInsertion = CurFn->InlineSites.insert({InlinedAt, InlineSite()});
+  auto SiteInsertion = CurFn->InlineSites.try_emplace(InlinedAt);
   InlineSite *Site = &SiteInsertion.first->second;
   if (SiteInsertion.second) {
     unsigned ParentFuncId = CurFn->FuncId;
@@ -2743,7 +2743,7 @@ TypeIndex CodeViewDebug::getCompleteTypeIndex(const DIType *Ty) {
   // Check if we've already translated the complete record type.
   // Insert the type with a null TypeIndex to signify that the type is currently
   // being lowered.
-  auto InsertResult = CompleteTypeIndices.insert({CTy, TypeIndex()});
+  auto InsertResult = CompleteTypeIndices.try_emplace(CTy);
   if (!InsertResult.second)
     return InsertResult.first->second;
 
@@ -3005,7 +3005,7 @@ void CodeViewDebug::collectLexicalBlockInfo(
   // Create a new CodeView lexical block for this lexical scope.  If we've
   // seen this DILexicalBlock before then the scope tree is malformed and
   // we can handle this gracefully by not processing it a second time.
-  auto BlockInsertion = CurFn->LexicalBlocks.insert({DILB, LexicalBlock()});
+  auto BlockInsertion = CurFn->LexicalBlocks.try_emplace(DILB);
   if (!BlockInsertion.second)
     return;
 

llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp

@@ -1691,8 +1691,7 @@ bool InstrRefBasedLDV::transferDebugInstrRef(MachineInstr &MI,
   // filled in later.
   for (const DbgOp &Op : DbgOps) {
     if (!Op.IsConst)
-      if (FoundLocs.insert({Op.ID, TransferTracker::LocationAndQuality()})
-              .second)
+      if (FoundLocs.try_emplace(Op.ID).second)
         ValuesToFind.push_back(Op.ID);
   }
 

llvm/lib/CodeGen/NonRelocatableStringpool.cpp

@@ -12,7 +12,7 @@
 namespace llvm {
 
 DwarfStringPoolEntryRef NonRelocatableStringpool::getEntry(StringRef S) {
-  auto I = Strings.insert({S, DwarfStringPoolEntry()});
+  auto I = Strings.try_emplace(S);
   auto &Entry = I.first->second;
   if (I.second || !Entry.isIndexed()) {
     Entry.Index = NumEntries++;

llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp

@@ -2656,7 +2656,7 @@ bool SIInsertWaitcnts::run(MachineFunction &MF) {
   // Keep iterating over the blocks in reverse post order, inserting and
   // updating s_waitcnt where needed, until a fix point is reached.
   for (auto *MBB : ReversePostOrderTraversal<MachineFunction *>(&MF))
-    BlockInfos.insert({MBB, BlockInfo()});
+    BlockInfos.try_emplace(MBB);
 
   std::unique_ptr<WaitcntBrackets> Brackets;
   bool Repeat;