Replace push_back(Constructor(foo)) with emplace_back(foo) for non-trivial types

If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.


Call sites were found with the ASTMatcher + some semi-automated cleanup.

memberCallExpr(
    argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
    on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
    hasArgument(0, bindTemporaryExpr(
                       hasType(recordDecl(hasNonTrivialDestructor())),
                       has(constructExpr()))),
    unless(isInTemplateInstantiation()))

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238602 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/CallGraph.h

@@ -230,7 +230,7 @@ public:
   void addCalledFunction(CallSite CS, CallGraphNode *M) {
     assert(!CS.getInstruction() || !CS.getCalledFunction() ||
            !CS.getCalledFunction()->isIntrinsic());
-    CalledFunctions.push_back(std::make_pair(CS.getInstruction(), M));
+    CalledFunctions.emplace_back(CS.getInstruction(), M);
     M->AddRef();
   }
 

include/llvm/Bitcode/BitstreamReader.h

@@ -113,7 +113,7 @@ public:
       return *const_cast<BlockInfo*>(BI);
 
     // Otherwise, add a new record.
-    BlockInfoRecords.push_back(BlockInfo());
+    BlockInfoRecords.emplace_back();
     BlockInfoRecords.back().BlockID = BlockID;
     return BlockInfoRecords.back();
   }

include/llvm/Bitcode/BitstreamWriter.h

@@ -215,7 +215,7 @@ public:
 
     // Push the outer block's abbrev set onto the stack, start out with an
     // empty abbrev set.
-    BlockScope.push_back(Block(OldCodeSize, BlockSizeWordIndex));
+    BlockScope.emplace_back(OldCodeSize, BlockSizeWordIndex);
     BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
 
     // If there is a blockinfo for this BlockID, add all the predefined abbrevs
@@ -503,7 +503,7 @@ private:
       return *BI;
 
     // Otherwise, add a new record.
-    BlockInfoRecords.push_back(BlockInfo());
+    BlockInfoRecords.emplace_back();
     BlockInfoRecords.back().BlockID = BlockID;
     return BlockInfoRecords.back();
   }

include/llvm/CodeGen/GCMetadata.h

@@ -121,7 +121,7 @@ public:
   /// label just prior to the safe point (if the code generator is using
   /// MachineModuleInfo).
   void addSafePoint(GC::PointKind Kind, MCSymbol *Label, DebugLoc DL) {
-    SafePoints.push_back(GCPoint(Kind, Label, DL));
+    SafePoints.emplace_back(Kind, Label, DL);
   }
 
   /// getFrameSize/setFrameSize - Records the function's frame size.

include/llvm/CodeGen/ScheduleDAGInstrs.h

@@ -260,7 +260,7 @@ namespace llvm {
 #ifndef NDEBUG
     const SUnit *Addr = SUnits.empty() ? nullptr : &SUnits[0];
 #endif
-    SUnits.push_back(SUnit(MI, (unsigned)SUnits.size()));
+    SUnits.emplace_back(MI, (unsigned)SUnits.size());
     assert((Addr == nullptr || Addr == &SUnits[0]) &&
            "SUnits std::vector reallocated on the fly!");
     SUnits.back().OrigNode = &SUnits.back();

include/llvm/ExecutionEngine/Orc/CompileOnDemandLayer.h

@@ -390,8 +390,7 @@ public:
       for (auto &F : *M) {
         if (F.isDeclaration())
           continue;
-        Partitioning.push_back(std::vector<Function*>());
+        Partitioning.emplace_back(1, &F);
-        Partitioning.back().push_back(&F);
       }
       addLogicalModule(*LogicalDylibs.back(),
                        std::shared_ptr<Module>(std::move(M)),

lib/Analysis/AliasSetTracker.cpp

@@ -130,7 +130,7 @@ void AliasSet::addPointer(AliasSetTracker &AST, PointerRec &Entry,
 void AliasSet::addUnknownInst(Instruction *I, AliasAnalysis &AA) {
   if (UnknownInsts.empty())
     addRef();
-  UnknownInsts.push_back(I);
+  UnknownInsts.emplace_back(I);
 
   if (!I->mayWriteToMemory()) {
     AliasTy = MayAlias;

lib/Analysis/ScalarEvolutionExpander.cpp

@@ -1712,7 +1712,7 @@ unsigned SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT,
     // would confuse the logic below that expects proper IVs.
     if (Value *V = SimplifyInstruction(Phi, DL, SE.TLI, SE.DT, SE.AC)) {
       Phi->replaceAllUsesWith(V);
-      DeadInsts.push_back(Phi);
+      DeadInsts.emplace_back(Phi);
       ++NumElim;
       DEBUG_WITH_TYPE(DebugType, dbgs()
                       << "INDVARS: Eliminated constant iv: " << *Phi << '\n');
@@ -1787,7 +1787,7 @@ unsigned SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT,
             CreateTruncOrBitCast(OrigInc, IsomorphicInc->getType(), IVName);
         }
         IsomorphicInc->replaceAllUsesWith(NewInc);
-        DeadInsts.push_back(IsomorphicInc);
+        DeadInsts.emplace_back(IsomorphicInc);
       }
     }
     DEBUG_WITH_TYPE(DebugType, dbgs()
@@ -1800,7 +1800,7 @@ unsigned SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT,
       NewIV = Builder.CreateTruncOrBitCast(OrigPhiRef, Phi->getType(), IVName);
     }
     Phi->replaceAllUsesWith(NewIV);
-    DeadInsts.push_back(Phi);
+    DeadInsts.emplace_back(Phi);
   }
   return NumElim;
 }

lib/AsmParser/LLParser.cpp

@@ -1902,9 +1902,9 @@ bool LLParser::ParseArgumentList(SmallVectorImpl<ArgInfo> &ArgList,
       return Error(TypeLoc, "invalid type for function argument");
 
     unsigned AttrIndex = 1;
-    ArgList.push_back(ArgInfo(TypeLoc, ArgTy,
+    ArgList.emplace_back(TypeLoc, ArgTy, AttributeSet::get(ArgTy->getContext(),
-                              AttributeSet::get(ArgTy->getContext(),
+                                                           AttrIndex++, Attrs),
-                                                AttrIndex++, Attrs), Name));
+                         std::move(Name));
 
     while (EatIfPresent(lltok::comma)) {
       // Handle ... at end of arg list.
@@ -1930,10 +1930,10 @@ bool LLParser::ParseArgumentList(SmallVectorImpl<ArgInfo> &ArgList,
       if (!ArgTy->isFirstClassType())
         return Error(TypeLoc, "invalid type for function argument");
 
-      ArgList.push_back(ArgInfo(TypeLoc, ArgTy,
+      ArgList.emplace_back(
-                                AttributeSet::get(ArgTy->getContext(),
+          TypeLoc, ArgTy,
-                                                  AttrIndex++, Attrs),
+          AttributeSet::get(ArgTy->getContext(), AttrIndex++, Attrs),
-                                Name));
+          std::move(Name));
     }
   }
 

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -63,9 +63,7 @@ public:
   // vector compatibility methods
   unsigned size() const { return ValuePtrs.size(); }
   void resize(unsigned N) { ValuePtrs.resize(N); }
-  void push_back(Value *V) {
+  void push_back(Value *V) { ValuePtrs.emplace_back(V); }
-    ValuePtrs.push_back(V);
-  }
 
   void clear() {
     assert(ResolveConstants.empty() && "Constants not resolved?");

lib/CodeGen/MachineModuleInfo.cpp

@@ -114,7 +114,7 @@ MCSymbol *MMIAddrLabelMap::getAddrLabelSymbol(BasicBlock *BB) {
 
   // Otherwise, this is a new entry, create a new symbol for it and add an
   // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
-  BBCallbacks.push_back(BB);
+  BBCallbacks.emplace_back(BB);
   BBCallbacks.back().setMap(this);
   Entry.Index = BBCallbacks.size()-1;
   Entry.Fn = BB->getParent();

lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

@@ -71,7 +71,7 @@ SUnit *ScheduleDAGSDNodes::newSUnit(SDNode *N) {
   if (!SUnits.empty())
     Addr = &SUnits[0];
 #endif
-  SUnits.push_back(SUnit(N, (unsigned)SUnits.size()));
+  SUnits.emplace_back(N, (unsigned)SUnits.size());
   assert((Addr == nullptr || Addr == &SUnits[0]) &&
          "SUnits std::vector reallocated on the fly!");
   SUnits.back().OrigNode = &SUnits.back();

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -7437,7 +7437,7 @@ bool SelectionDAGBuilder::buildJumpTable(CaseClusterVector &Clusters,
   JumpTableHeader JTH(Clusters[First].Low->getValue(),
                       Clusters[Last].High->getValue(), SI->getCondition(),
                       nullptr, false);
-  JTCases.push_back(JumpTableBlock(JTH, JT));
+  JTCases.emplace_back(std::move(JTH), std::move(JT));
 
   JTCluster = CaseCluster::jumpTable(Clusters[First].Low, Clusters[Last].High,
                                      JTCases.size() - 1, Weight);
@@ -7650,9 +7650,9 @@ bool SelectionDAGBuilder::buildBitTests(CaseClusterVector &Clusters,
         FuncInfo.MF->CreateMachineBasicBlock(SI->getParent());
     BTI.push_back(BitTestCase(CB.Mask, BitTestBB, CB.BB, CB.ExtraWeight));
   }
-  BitTestCases.push_back(BitTestBlock(LowBound, CmpRange, SI->getCondition(),
+  BitTestCases.emplace_back(std::move(LowBound), std::move(CmpRange),
-                                      -1U, MVT::Other, false, nullptr,
+                            SI->getCondition(), -1U, MVT::Other, false, nullptr,
-                                      nullptr, std::move(BTI)));
+                            nullptr, std::move(BTI));
 
   BTCluster = CaseCluster::bitTests(Clusters[First].Low, Clusters[Last].High,
                                     BitTestCases.size() - 1, TotalWeight);

lib/DebugInfo/DWARF/DWARFContext.cpp

@@ -352,7 +352,7 @@ void DWARFContext::parseTypeUnits() {
   if (!TUs.empty())
     return;
   for (const auto &I : getTypesSections()) {
-    TUs.push_back(DWARFUnitSection<DWARFTypeUnit>());
+    TUs.emplace_back();
     TUs.back().parse(*this, I.second);
   }
 }
@@ -365,7 +365,7 @@ void DWARFContext::parseDWOTypeUnits() {
   if (!DWOTUs.empty())
     return;
   for (const auto &I : getTypesDWOSections()) {
-    DWOTUs.push_back(DWARFUnitSection<DWARFTypeUnit>());
+    DWOTUs.emplace_back();
     DWOTUs.back().parseDWO(*this, I.second);
   }
 }

lib/ExecutionEngine/ExecutionEngine.cpp

@@ -438,7 +438,7 @@ int ExecutionEngine::runFunctionAsMain(Function *Fn,
       if (NumArgs > 2) {
         std::vector<std::string> EnvVars;
         for (unsigned i = 0; envp[i]; ++i)
-          EnvVars.push_back(envp[i]);
+          EnvVars.emplace_back(envp[i]);
         // Arg #2 = envp.
         GVArgs.push_back(PTOGV(CEnv.reset(Fn->getContext(), this, EnvVars)));
       }

lib/ExecutionEngine/ExecutionEngineBindings.cpp

@@ -254,11 +254,8 @@ int LLVMRunFunctionAsMain(LLVMExecutionEngineRef EE, LLVMValueRef F,
                           unsigned ArgC, const char * const *ArgV,
                           const char * const *EnvP) {
   unwrap(EE)->finalizeObject();
-  
+
-  std::vector<std::string> ArgVec;
+  std::vector<std::string> ArgVec(ArgV, ArgV + ArgC);
-  for (unsigned I = 0; I != ArgC; ++I)
-    ArgVec.push_back(ArgV[I]);
-  
   return unwrap(EE)->runFunctionAsMain(unwrap<Function>(F), ArgVec, EnvP);
 }
 

lib/ExecutionEngine/Interpreter/Execution.cpp

@@ -2079,7 +2079,7 @@ void Interpreter::callFunction(Function *F,
           ECStack.back().Caller.arg_size() == ArgVals.size()) &&
          "Incorrect number of arguments passed into function call!");
   // Make a new stack frame... and fill it in.
-  ECStack.push_back(ExecutionContext());
+  ECStack.emplace_back();
   ExecutionContext &StackFrame = ECStack.back();
   StackFrame.CurFunction = F;
 

lib/MC/MCParser/AsmParser.cpp

@@ -1949,7 +1949,7 @@ bool AsmParser::parseMacroArgument(MCAsmMacroArgument &MA, bool Vararg) {
   if (Vararg) {
     if (Lexer.isNot(AsmToken::EndOfStatement)) {
       StringRef Str = parseStringToEndOfStatement();
-      MA.push_back(AsmToken(AsmToken::String, Str));
+      MA.emplace_back(AsmToken::String, Str);
     }
     return false;
   }
@@ -4346,8 +4346,7 @@ MCAsmMacro *AsmParser::parseMacroLikeBody(SMLoc DirectiveLoc) {
   StringRef Body = StringRef(BodyStart, BodyEnd - BodyStart);
 
   // We Are Anonymous.
-  MacroLikeBodies.push_back(
+  MacroLikeBodies.emplace_back(StringRef(), Body, MCAsmMacroParameters());
-      MCAsmMacro(StringRef(), Body, MCAsmMacroParameters()));
   return &MacroLikeBodies.back();
 }
 
@@ -4490,7 +4489,7 @@ bool AsmParser::parseDirectiveIrpc(SMLoc DirectiveLoc) {
   StringRef Values = A.front().front().getString();
   for (std::size_t I = 0, End = Values.size(); I != End; ++I) {
     MCAsmMacroArgument Arg;
-    Arg.push_back(AsmToken(AsmToken::Identifier, Values.slice(I, I + 1)));
+    Arg.emplace_back(AsmToken::Identifier, Values.slice(I, I + 1));
 
     // Note that the AtPseudoVariable is enabled for instantiations of .irpc.
     // This is undocumented, but GAS seems to support it.

lib/TableGen/TGParser.cpp

@@ -1601,7 +1601,7 @@ TGParser::ParseDagArgList(Record *CurRec) {
     // DagArg ::= VARNAME
     if (Lex.getCode() == tgtok::VarName) {
       // A missing value is treated like '?'.
-      Result.push_back(std::make_pair(UnsetInit::get(), Lex.getCurStrVal()));
+      Result.emplace_back(UnsetInit::get(), Lex.getCurStrVal());
       Lex.Lex();
     } else {
       // DagArg ::= Value (':' VARNAME)?
@@ -2174,7 +2174,7 @@ std::vector<LetRecord> TGParser::ParseLetList() {
     if (!Val) return std::vector<LetRecord>();
 
     // Now that we have everything, add the record.
-    Result.push_back(LetRecord(Name, Bits, Val, NameLoc));
+    Result.emplace_back(std::move(Name), std::move(Bits), Val, NameLoc);
 
     if (Lex.getCode() != tgtok::comma)
       return Result;

lib/Transforms/IPO/MergeFunctions.cpp

@@ -1465,7 +1465,7 @@ void MergeFunctions::remove(Function *F) {
   if (Erased) {
     DEBUG(dbgs() << "Removed " << F->getName()
                  << " from set and deferred it.\n");
-    Deferred.push_back(F);
+    Deferred.emplace_back(F);
   }
 }
 

lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -1843,7 +1843,7 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
 
       case Instruction::BitCast:
       case Instruction::GetElementPtr:
-        Users.push_back(I);
+        Users.emplace_back(I);
         Worklist.push_back(I);
         continue;
 
@@ -1852,7 +1852,7 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
         // We can fold eq/ne comparisons with null to false/true, respectively.
         if (!ICI->isEquality() || !isa<ConstantPointerNull>(ICI->getOperand(1)))
           return false;
-        Users.push_back(I);
+        Users.emplace_back(I);
         continue;
       }
 
@@ -1878,13 +1878,13 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
           case Intrinsic::lifetime_start:
           case Intrinsic::lifetime_end:
           case Intrinsic::objectsize:
-            Users.push_back(I);
+            Users.emplace_back(I);
             continue;
           }
         }
 
         if (isFreeCall(I, TLI)) {
-          Users.push_back(I);
+          Users.emplace_back(I);
           continue;
         }
         return false;
@@ -1893,7 +1893,7 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
         StoreInst *SI = cast<StoreInst>(I);
         if (SI->isVolatile() || SI->getPointerOperand() != PI)
           return false;
-        Users.push_back(I);
+        Users.emplace_back(I);
         continue;
       }
       }

lib/Transforms/Scalar/IndVarSimplify.cpp

@@ -1102,7 +1102,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) {
         IRBuilder<> Builder(WidePhi->getParent()->getFirstInsertionPt());
         Value *Trunc = Builder.CreateTrunc(WidePhi, DU.NarrowDef->getType());
         UsePhi->replaceAllUsesWith(Trunc);
-        DeadInsts.push_back(UsePhi);
+        DeadInsts.emplace_back(UsePhi);
         DEBUG(dbgs() << "INDVARS: Widen lcssa phi " << *UsePhi
               << " to " << *WidePhi << "\n");
       }
@@ -1135,7 +1135,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) {
             << " replaced by " << *DU.WideDef << "\n");
       ++NumElimExt;
       DU.NarrowUse->replaceAllUsesWith(NewDef);
-      DeadInsts.push_back(DU.NarrowUse);
+      DeadInsts.emplace_back(DU.NarrowUse);
     }
     // Now that the extend is gone, we want to expose it's uses for potential
     // further simplification. We don't need to directly inform SimplifyIVUsers
@@ -1188,7 +1188,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) {
   if (WideAddRec != SE->getSCEV(WideUse)) {
     DEBUG(dbgs() << "Wide use expression mismatch: " << *WideUse
           << ": " << *SE->getSCEV(WideUse) << " != " << *WideAddRec << "\n");
-    DeadInsts.push_back(WideUse);
+    DeadInsts.emplace_back(WideUse);
     return nullptr;
   }
 
@@ -1285,7 +1285,7 @@ PHINode *WidenIV::CreateWideIV(SCEVExpander &Rewriter) {
 
     // WidenIVUse may have removed the def-use edge.
     if (DU.NarrowDef->use_empty())
-      DeadInsts.push_back(DU.NarrowDef);
+      DeadInsts.emplace_back(DU.NarrowDef);
   }
   return WidePhi;
 }

lib/Transforms/Scalar/LoopStrengthReduce.cpp

@@ -811,7 +811,7 @@ DeleteTriviallyDeadInstructions(SmallVectorImpl<WeakVH> &DeadInsts) {
       if (Instruction *U = dyn_cast<Instruction>(O)) {
         O = nullptr;
         if (U->use_empty())
-          DeadInsts.push_back(U);
+          DeadInsts.emplace_back(U);
       }
 
     I->eraseFromParent();
@@ -2917,7 +2917,7 @@ void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter,
       IVOper = Builder.CreateTruncOrBitCast(IVOper, OperTy, "lsr.chain");
     }
     Inc.UserInst->replaceUsesOfWith(Inc.IVOperand, IVOper);
-    DeadInsts.push_back(Inc.IVOperand);
+    DeadInsts.emplace_back(Inc.IVOperand);
   }
   // If LSR created a new, wider phi, we may also replace its postinc. We only
   // do this if we also found a wide value for the head of the chain.
@@ -2939,7 +2939,7 @@ void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter,
         IVOper = Builder.CreatePointerCast(IVSrc, PostIncTy, "lsr.chain");
       }
       Phi->replaceUsesOfWith(PostIncV, IVOper);
-      DeadInsts.push_back(PostIncV);
+      DeadInsts.emplace_back(PostIncV);
     }
   }
 }
@@ -4594,7 +4594,7 @@ Value *LSRInstance::Expand(const LSRFixup &LF,
   // form, update the ICmp's other operand.
   if (LU.Kind == LSRUse::ICmpZero) {
     ICmpInst *CI = cast<ICmpInst>(LF.UserInst);
-    DeadInsts.push_back(CI->getOperand(1));
+    DeadInsts.emplace_back(CI->getOperand(1));
     assert(!F.BaseGV && "ICmp does not support folding a global value and "
                            "a scale at the same time!");
     if (F.Scale == -1) {
@@ -4737,7 +4737,7 @@ void LSRInstance::Rewrite(const LSRFixup &LF,
       LF.UserInst->replaceUsesOfWith(LF.OperandValToReplace, FullV);
   }
 
-  DeadInsts.push_back(LF.OperandValToReplace);
+  DeadInsts.emplace_back(LF.OperandValToReplace);
 }
 
 /// ImplementSolution - Rewrite all the fixup locations with new values,

lib/Transforms/Scalar/Reassociate.cpp

@@ -733,7 +733,7 @@ static bool LinearizeExprTree(BinaryOperator *I,
   if (Ops.empty()) {
     Constant *Identity = ConstantExpr::getBinOpIdentity(Opcode, I->getType());
     assert(Identity && "Associative operation without identity!");
-    Ops.push_back(std::make_pair(Identity, APInt(Bitwidth, 1)));
+    Ops.emplace_back(Identity, APInt(Bitwidth, 1));
   }
 
   return Changed;

lib/Transforms/Utils/PromoteMemoryToRegister.cpp

@@ -636,7 +636,7 @@ void PromoteMem2Reg::run() {
   // and inserting the phi nodes we marked as necessary
   //
   std::vector<RenamePassData> RenamePassWorkList;
-  RenamePassWorkList.push_back(RenamePassData(F.begin(), nullptr, Values));
+  RenamePassWorkList.emplace_back(F.begin(), nullptr, std::move(Values));
   do {
     RenamePassData RPD;
     RPD.swap(RenamePassWorkList.back());
@@ -973,7 +973,7 @@ NextIteration:
 
   for (; I != E; ++I)
     if (VisitedSuccs.insert(*I).second)
-      Worklist.push_back(RenamePassData(*I, Pred, IncomingVals));
+      Worklist.emplace_back(*I, Pred, IncomingVals);
 
   goto NextIteration;
 }

lib/Transforms/Utils/SimplifyIndVar.cpp

@@ -141,7 +141,7 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand)
   ++NumElimOperand;
   Changed = true;
   if (IVOperand->use_empty())
-    DeadInsts.push_back(IVOperand);
+    DeadInsts.emplace_back(IVOperand);
   return IVSrc;
 }
 
@@ -178,7 +178,7 @@ void SimplifyIndvar::eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand) {
   DEBUG(dbgs() << "INDVARS: Eliminated comparison: " << *ICmp << '\n');
   ++NumElimCmp;
   Changed = true;
-  DeadInsts.push_back(ICmp);
+  DeadInsts.emplace_back(ICmp);
 }
 
 /// SimplifyIVUsers helper for eliminating useless
@@ -229,7 +229,7 @@ void SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem,
   DEBUG(dbgs() << "INDVARS: Simplified rem: " << *Rem << '\n');
   ++NumElimRem;
   Changed = true;
-  DeadInsts.push_back(Rem);
+  DeadInsts.emplace_back(Rem);
 }
 
 /// Eliminate an operation that consumes a simple IV and has
@@ -260,7 +260,7 @@ bool SimplifyIndvar::eliminateIVUser(Instruction *UseInst,
   UseInst->replaceAllUsesWith(IVOperand);
   ++NumElimIdentity;
   Changed = true;
-  DeadInsts.push_back(UseInst);
+  DeadInsts.emplace_back(UseInst);
   return true;
 }
 
@@ -386,7 +386,7 @@ Instruction *SimplifyIndvar::splitOverflowIntrinsic(Instruction *IVUser,
          "Bad add instruction created from overflow intrinsic.");
 
   AddVal->replaceAllUsesWith(AddInst);
-  DeadInsts.push_back(AddVal);
+  DeadInsts.emplace_back(AddVal);
   return AddInst;
 }
 

lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -472,7 +472,7 @@ private:
 
   /// Create a new VectorizableTree entry.
   TreeEntry *newTreeEntry(ArrayRef<Value *> VL, bool Vectorized) {
-    VectorizableTree.push_back(TreeEntry());
+    VectorizableTree.emplace_back();
     int idx = VectorizableTree.size() - 1;
     TreeEntry *Last = &VectorizableTree[idx];
     Last->Scalars.insert(Last->Scalars.begin(), VL.begin(), VL.end());

tools/bugpoint/CrashDebugger.cpp

@@ -385,8 +385,7 @@ bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
   std::vector<std::pair<std::string, std::string> > BlockInfo;
 
   for (BasicBlock *BB : Blocks)
-    BlockInfo.push_back(std::make_pair(BB->getParent()->getName(),
+    BlockInfo.emplace_back(BB->getParent()->getName(), BB->getName());
-                                       BB->getName()));
 
   // Now run the CFG simplify pass on the function...
   std::vector<std::string> Passes;

tools/bugpoint/Miscompilation.cpp

@@ -386,10 +386,8 @@ static bool ExtractLoops(BugDriver &BD,
       // that masked the error.  Stop loop extraction now.
 
       std::vector<std::pair<std::string, FunctionType*> > MisCompFunctions;
-      for (unsigned i = 0, e = MiscompiledFunctions.size(); i != e; ++i) {
+      for (Function *F : MiscompiledFunctions) {
-        Function *F = MiscompiledFunctions[i];
+        MisCompFunctions.emplace_back(F->getName(), F->getFunctionType());
-        MisCompFunctions.push_back(std::make_pair(F->getName(),
-                                                  F->getFunctionType()));
       }
 
       if (Linker::LinkModules(ToNotOptimize, ToOptimizeLoopExtracted))
@@ -414,8 +412,7 @@ static bool ExtractLoops(BugDriver &BD,
     for (Module::iterator I = ToOptimizeLoopExtracted->begin(),
            E = ToOptimizeLoopExtracted->end(); I != E; ++I)
       if (!I->isDeclaration())
-        MisCompFunctions.push_back(std::make_pair(I->getName(),
+        MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
-                                                  I->getFunctionType()));
 
     // Okay, great!  Now we know that we extracted a loop and that loop
     // extraction both didn't break the program, and didn't mask the problem.
@@ -596,8 +593,7 @@ static bool ExtractBlocks(BugDriver &BD,
   for (Module::iterator I = Extracted->begin(), E = Extracted->end();
        I != E; ++I)
     if (!I->isDeclaration())
-      MisCompFunctions.push_back(std::make_pair(I->getName(),
+      MisCompFunctions.emplace_back(I->getName(), I->getFunctionType());
-                                                I->getFunctionType()));
 
   if (Linker::LinkModules(ProgClone, Extracted.get()))
     exit(1);

tools/lli/OrcLazyJIT.h

@@ -116,8 +116,7 @@ public:
     orc::CtorDtorRunner<CODLayerT> CtorRunner(std::move(CtorNames), H);
     CtorRunner.runViaLayer(CODLayer);
 
-    IRStaticDestructorRunners.push_back(
+    IRStaticDestructorRunners.emplace_back(std::move(DtorNames), H);
-        orc::CtorDtorRunner<CODLayerT>(std::move(DtorNames), H));
 
     return H;
   }

tools/llvm-cov/CodeCoverage.cpp

@@ -116,8 +116,7 @@ CodeCoverageTool::getSourceFile(StringRef SourceFile) {
     error(EC.message(), SourceFile);
     return EC;
   }
-  LoadedSourceFiles.push_back(
+  LoadedSourceFiles.emplace_back(SourceFile, std::move(Buffer.get()));
-      std::make_pair(SourceFile, std::move(Buffer.get())));
   return *LoadedSourceFiles.back().second;
 }
 

tools/llvm-pdbdump/LinePrinter.h

@@ -41,7 +41,7 @@ private:
   void SetFilters(std::list<Regex> &List, Iter Begin, Iter End) {
     List.clear();
     for (; Begin != End; ++Begin)
-      List.push_back(StringRef(*Begin));
+      List.emplace_back(StringRef(*Begin));
   }
 
   raw_ostream &OS;

utils/FileCheck/FileCheck.cpp

@@ -946,10 +946,7 @@ static bool ReadCheckFile(SourceMgr &SM,
     }
 
     // Okay, add the string we captured to the output vector and move on.
-    CheckStrings.push_back(CheckString(P,
+    CheckStrings.emplace_back(P, UsedPrefix, PatternLoc, CheckTy);
-                                       UsedPrefix,
-                                       PatternLoc,
-                                       CheckTy));
     std::swap(DagNotMatches, CheckStrings.back().DagNotStrings);
     DagNotMatches = ImplicitNegativeChecks;
   }
@@ -957,10 +954,9 @@ static bool ReadCheckFile(SourceMgr &SM,
   // Add an EOF pattern for any trailing CHECK-DAG/-NOTs, and use the first
   // prefix as a filler for the error message.
   if (!DagNotMatches.empty()) {
-    CheckStrings.push_back(CheckString(Pattern(Check::CheckEOF),
+    CheckStrings.emplace_back(Pattern(Check::CheckEOF), *CheckPrefixes.begin(),
-                                       *CheckPrefixes.begin(),
+                              SMLoc::getFromPointer(Buffer.data()),
-                                       SMLoc::getFromPointer(Buffer.data()),
+                              Check::CheckEOF);
-                                       Check::CheckEOF));
     std::swap(DagNotMatches, CheckStrings.back().DagNotStrings);
   }
 

utils/TableGen/AsmMatcherEmitter.cpp

@@ -1797,7 +1797,7 @@ static void emitConvertFuncs(CodeGenTarget &Target, StringRef ClassName,
                                     getEnumNameForToken(AsmMatchConverter));
 
       // Add the converter row for this instruction.
-      ConversionTable.push_back(std::vector<uint8_t>());
+      ConversionTable.emplace_back();
       ConversionTable.back().push_back(KindID);
       ConversionTable.back().push_back(CVT_Done);
 
@@ -2161,8 +2161,7 @@ static void emitMatchTokenString(CodeGenTarget &Target,
   std::vector<StringMatcher::StringPair> Matches;
   for (const auto &CI : Infos) {
     if (CI.Kind == ClassInfo::Token)
-      Matches.push_back(
+      Matches.emplace_back(CI.ValueName, "return " + CI.Name + ";");
-          StringMatcher::StringPair(CI.ValueName, "return " + CI.Name + ";"));
   }
 
   OS << "static MatchClassKind matchTokenString(StringRef Name) {\n";
@@ -2184,9 +2183,8 @@ static void emitMatchRegisterName(CodeGenTarget &Target, Record *AsmParser,
     if (Reg.TheDef->getValueAsString("AsmName").empty())
       continue;
 
-    Matches.push_back(
+    Matches.emplace_back(Reg.TheDef->getValueAsString("AsmName"),
-        StringMatcher::StringPair(Reg.TheDef->getValueAsString("AsmName"),
+                         "return " + utostr(Reg.EnumValue) + ";");
-                                  "return " + utostr(Reg.EnumValue) + ";"));
   }
 
   OS << "static unsigned MatchRegisterName(StringRef Name) {\n";

utils/TableGen/AsmWriterEmitter.cpp

@@ -1105,9 +1105,8 @@ AsmWriterEmitter::AsmWriterEmitter(RecordKeeper &R) : Records(R), Target(R) {
   Record *AsmWriter = Target.getAsmWriter();
   for (const CodeGenInstruction *I : Target.instructions())
     if (!I->AsmString.empty() && I->TheDef->getName() != "PHI")
-      Instructions.push_back(
+      Instructions.emplace_back(*I, AsmWriter->getValueAsInt("Variant"),
-          AsmWriterInst(*I, AsmWriter->getValueAsInt("Variant"),
+                                AsmWriter->getValueAsInt("PassSubtarget"));
-                        AsmWriter->getValueAsInt("PassSubtarget")));
 
   // Get the instruction numbering.
   NumberedInstructions = &Target.getInstructionsByEnumValue();

utils/TableGen/AsmWriterInst.cpp

@@ -163,27 +163,22 @@ AsmWriterInst::AsmWriterInst(const CodeGenInstruction &CGI, unsigned Variant,
 
       if (VarName.empty()) {
         // Just a modifier, pass this into PrintSpecial.
-        Operands.push_back(AsmWriterOperand("PrintSpecial",
+        Operands.emplace_back("PrintSpecial", ~0U, ~0U, Modifier,
-                                            ~0U,
+                              PassSubtarget);
-                                            ~0U,
-                                            Modifier,
-                                            PassSubtarget));
       } else {
         // Otherwise, normal operand.
         unsigned OpNo = CGI.Operands.getOperandNamed(VarName);
         CGIOperandList::OperandInfo OpInfo = CGI.Operands[OpNo];
 
         unsigned MIOp = OpInfo.MIOperandNo;
-        Operands.push_back(AsmWriterOperand(OpInfo.PrinterMethodName,
+        Operands.emplace_back(OpInfo.PrinterMethodName, OpNo, MIOp, Modifier,
-                                            OpNo, MIOp, Modifier,
+                              PassSubtarget);
-                                            PassSubtarget));
       }
       LastEmitted = VarEnd;
     }
   }
 
-  Operands.push_back(AsmWriterOperand("return;",
+  Operands.emplace_back("return;", AsmWriterOperand::isLiteralStatementOperand);
-    AsmWriterOperand::isLiteralStatementOperand));
 }
 
 /// MatchesAllButOneOp - If this instruction is exactly identical to the

utils/TableGen/CodeGenDAGPatterns.cpp

@@ -3798,13 +3798,11 @@ void CodeGenDAGPatterns::GenerateVariants() {
       if (AlreadyExists) continue;
 
       // Otherwise, add it to the list of patterns we have.
-      PatternsToMatch.
+      PatternsToMatch.emplace_back(
-        push_back(PatternToMatch(PatternsToMatch[i].getSrcRecord(),
+          PatternsToMatch[i].getSrcRecord(), PatternsToMatch[i].getPredicates(),
-                                 PatternsToMatch[i].getPredicates(),
+          Variant, PatternsToMatch[i].getDstPattern(),
-                                 Variant, PatternsToMatch[i].getDstPattern(),
+          PatternsToMatch[i].getDstRegs(),
-                                 PatternsToMatch[i].getDstRegs(),
+          PatternsToMatch[i].getAddedComplexity(), Record::getNewUID());
-                                 PatternsToMatch[i].getAddedComplexity(),
-                                 Record::getNewUID()));
     }
 
     DEBUG(errs() << "\n");

utils/TableGen/CodeGenInstruction.cpp

@@ -115,9 +115,9 @@ CGIOperandList::CGIOperandList(Record *R) : TheDef(R) {
       PrintFatalError("In instruction '" + R->getName() + "', operand #" +
                       Twine(i) + " has the same name as a previous operand!");
 
-    OperandList.push_back(OperandInfo(Rec, ArgName, PrintMethod, EncoderMethod,
+    OperandList.emplace_back(Rec, ArgName, PrintMethod, EncoderMethod,
-                                      OperandNamespace + "::" + OperandType,
+                             OperandNamespace + "::" + OperandType, MIOperandNo,
-				      MIOperandNo, NumOps, MIOpInfo));
+                             NumOps, MIOpInfo);
     MIOperandNo += NumOps;
   }
 
@@ -642,9 +642,9 @@ CodeGenInstAlias::CodeGenInstAlias(Record *R, unsigned Variant,
 
           // Take care to instantiate each of the suboperands with the correct
           // nomenclature: $foo.bar
-          ResultOperands.push_back(
+          ResultOperands.emplace_back(Result->getArgName(AliasOpNo) + "." +
-              ResultOperand(Result->getArgName(AliasOpNo) + "." +
+                                          MIOI->getArgName(SubOp),
-                            MIOI->getArgName(SubOp), SubRec));
+                                      SubRec);
           ResultInstOperandIndex.push_back(std::make_pair(i, SubOp));
          }
          ++AliasOpNo;

utils/TableGen/CodeGenRegisters.cpp

@@ -994,7 +994,7 @@ CodeGenRegBank::CodeGenRegBank(RecordKeeper &Records) {
 
   // Allocate user-defined register classes.
   for (auto *RC : RCs) {
-    RegClasses.push_back(CodeGenRegisterClass(*this, RC));
+    RegClasses.emplace_back(*this, RC);
     addToMaps(&RegClasses.back());
   }
 
@@ -1056,7 +1056,7 @@ CodeGenRegBank::getOrCreateSubClass(const CodeGenRegisterClass *RC,
     return FoundI->second;
 
   // Sub-class doesn't exist, create a new one.
-  RegClasses.push_back(CodeGenRegisterClass(*this, Name, K));
+  RegClasses.emplace_back(*this, Name, K);
   addToMaps(&RegClasses.back());
   return &RegClasses.back();
 }

utils/TableGen/CodeGenSchedule.cpp

@@ -145,8 +145,7 @@ void CodeGenSchedModels::collectProcModels() {
   // Use idx=0 for NoModel/NoItineraries.
   Record *NoModelDef = Records.getDef("NoSchedModel");
   Record *NoItinsDef = Records.getDef("NoItineraries");
-  ProcModels.push_back(CodeGenProcModel(0, "NoSchedModel",
+  ProcModels.emplace_back(0, "NoSchedModel", NoModelDef, NoItinsDef);
-                                        NoModelDef, NoItinsDef));
   ProcModelMap[NoModelDef] = 0;
 
   // For each processor, find a unique machine model.
@@ -164,16 +163,14 @@ void CodeGenSchedModels::addProcModel(Record *ProcDef) {
   std::string Name = ModelKey->getName();
   if (ModelKey->isSubClassOf("SchedMachineModel")) {
     Record *ItinsDef = ModelKey->getValueAsDef("Itineraries");
-    ProcModels.push_back(
+    ProcModels.emplace_back(ProcModels.size(), Name, ModelKey, ItinsDef);
-      CodeGenProcModel(ProcModels.size(), Name, ModelKey, ItinsDef));
   }
   else {
     // An itinerary is defined without a machine model. Infer a new model.
     if (!ModelKey->getValueAsListOfDefs("IID").empty())
       Name = Name + "Model";
-    ProcModels.push_back(
+    ProcModels.emplace_back(ProcModels.size(), Name,
-      CodeGenProcModel(ProcModels.size(), Name,
+                            ProcDef->getValueAsDef("SchedModel"), ModelKey);
-                       ProcDef->getValueAsDef("SchedModel"), ModelKey));
   }
   DEBUG(ProcModels.back().dump());
 }
@@ -281,12 +278,12 @@ void CodeGenSchedModels::collectSchedRW() {
   std::sort(SWDefs.begin(), SWDefs.end(), LessRecord());
   for (RecIter SWI = SWDefs.begin(), SWE = SWDefs.end(); SWI != SWE; ++SWI) {
     assert(!getSchedRWIdx(*SWI, /*IsRead=*/false) && "duplicate SchedWrite");
-    SchedWrites.push_back(CodeGenSchedRW(SchedWrites.size(), *SWI));
+    SchedWrites.emplace_back(SchedWrites.size(), *SWI);
   }
   std::sort(SRDefs.begin(), SRDefs.end(), LessRecord());
   for (RecIter SRI = SRDefs.begin(), SRE = SRDefs.end(); SRI != SRE; ++SRI) {
     assert(!getSchedRWIdx(*SRI, /*IsRead-*/true) && "duplicate SchedWrite");
-    SchedReads.push_back(CodeGenSchedRW(SchedReads.size(), *SRI));
+    SchedReads.emplace_back(SchedReads.size(), *SRI);
   }
   // Initialize WriteSequence vectors.
   for (std::vector<CodeGenSchedRW>::iterator WI = SchedWrites.begin(),

utils/TableGen/FixedLenDecoderEmitter.cpp

@@ -610,7 +610,7 @@ void Filter::emitTableEntry(DecoderTableInfo &TableInfo) const {
   TableInfo.Table.push_back(NumBits);
 
   // A new filter entry begins a new scope for fixup resolution.
-  TableInfo.FixupStack.push_back(FixupList());
+  TableInfo.FixupStack.emplace_back();
 
   DecoderTable &Table = TableInfo.Table;
 
@@ -1333,7 +1333,7 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo,
 
   // complex singletons need predicate checks from the first singleton
   // to refer forward to the variable filterchooser that follows.
-  TableInfo.FixupStack.push_back(FixupList());
+  TableInfo.FixupStack.emplace_back();
 
   emitSingletonTableEntry(TableInfo, Opc);
 
@@ -1350,7 +1350,7 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo,
 void FilterChooser::runSingleFilter(unsigned startBit, unsigned numBit,
                                     bool mixed) {
   Filters.clear();
-  Filters.push_back(Filter(*this, startBit, numBit, true));
+  Filters.emplace_back(*this, startBit, numBit, true);
   BestIndex = 0; // Sole Filter instance to choose from.
   bestFilter().recurse();
 }
@@ -1360,9 +1360,9 @@ void FilterChooser::runSingleFilter(unsigned startBit, unsigned numBit,
 void FilterChooser::reportRegion(bitAttr_t RA, unsigned StartBit,
                                  unsigned BitIndex, bool AllowMixed) {
   if (RA == ATTR_MIXED && AllowMixed)
-    Filters.push_back(Filter(*this, StartBit, BitIndex - StartBit, true));
+    Filters.emplace_back(*this, StartBit, BitIndex - StartBit, true);
   else if (RA == ATTR_ALL_SET && !AllowMixed)
-    Filters.push_back(Filter(*this, StartBit, BitIndex - StartBit, false));
+    Filters.emplace_back(*this, StartBit, BitIndex - StartBit, false);
 }
 
 // FilterProcessor scans the well-known encoding bits of the instructions and
@@ -2179,7 +2179,7 @@ void FixedLenDecoderEmitter::run(raw_ostream &o) {
     TableInfo.Table.clear();
     TableInfo.FixupStack.clear();
     TableInfo.Table.reserve(16384);
-    TableInfo.FixupStack.push_back(FixupList());
+    TableInfo.FixupStack.emplace_back();
     FC.emitTableEntries(TableInfo);
     // Any NumToSkip fixups in the top level scope can resolve to the
     // OPC_Fail at the end of the table.

utils/TableGen/IntrinsicEmitter.cpp

@@ -760,7 +760,7 @@ static void EmitTargetBuiltins(const std::map<std::string, std::string> &BIM,
        E = BIM.end(); I != E; ++I) {
     std::string ResultCode =
     "return " + TargetPrefix + "Intrinsic::" + I->second + ";";
-    Results.push_back(StringMatcher::StringPair(I->first, ResultCode));
+    Results.emplace_back(I->first, ResultCode);
   }
 
   StringMatcher("BuiltinName", Results, OS).Emit();