diff --git a/include/llvm/ADT/DirectedGraph.h b/include/llvm/ADT/DirectedGraph.h
index ec7d754f6e0..e8bb9e6b229 100644
--- a/include/llvm/ADT/DirectedGraph.h
+++ b/include/llvm/ADT/DirectedGraph.h
@@ -229,7 +229,7 @@ public:
       if (*Node == N)
         continue;
       Node->findEdgesTo(N, TempList);
-      EL.insert(EL.end(), TempList.begin(), TempList.end());
+      llvm::append_range(EL, TempList);
       TempList.clear();
     }
     return !EL.empty();
diff --git a/include/llvm/IR/InstrTypes.h b/include/llvm/IR/InstrTypes.h
index 8a702e3c9c5..631665e3fc5 100644
--- a/include/llvm/IR/InstrTypes.h
+++ b/include/llvm/IR/InstrTypes.h
@@ -1126,7 +1126,7 @@ public:
 
   explicit OperandBundleDefT(const OperandBundleUse &OBU) {
     Tag = std::string(OBU.getTagName());
-    Inputs.insert(Inputs.end(), OBU.Inputs.begin(), OBU.Inputs.end());
+    llvm::append_range(Inputs, OBU.Inputs);
   }
 
   ArrayRef<InputTy> inputs() const { return Inputs; }
diff --git a/include/llvm/Support/CFGDiff.h b/include/llvm/Support/CFGDiff.h
index a4a4b2ca44b..c90b9aca78b 100644
--- a/include/llvm/Support/CFGDiff.h
+++ b/include/llvm/Support/CFGDiff.h
@@ -152,7 +152,7 @@ public:
 
     // Add children present in the snapshot for not in the real CFG.
     auto &AddedChildren = It->second.DI[1];
-    Res.insert(Res.end(), AddedChildren.begin(), AddedChildren.end());
+    llvm::append_range(Res, AddedChildren);
 
     return Res;
   }
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index b2bb6728c67..28493dd070d 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -6358,8 +6358,7 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
     }
     case bitc::FS_TYPE_TESTS:
       assert(PendingTypeTests.empty());
-      PendingTypeTests.insert(PendingTypeTests.end(), Record.begin(),
-                              Record.end());
+      llvm::append_range(PendingTypeTests, Record);
       break;
 
     case bitc::FS_TYPE_TEST_ASSUME_VCALLS:
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 4b81ccde4ab..9f62cce028f 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -3629,7 +3629,7 @@ static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
       Record.clear();
       Record.push_back(VC.VFunc.GUID);
       Record.push_back(VC.VFunc.Offset);
-      Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
+      llvm::append_range(Record, VC.Args);
       Stream.EmitRecord(Ty, Record);
     }
   };
@@ -3703,7 +3703,7 @@ static void writeWholeProgramDevirtResolutionByArg(
     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
     const WholeProgramDevirtResolution::ByArg &ByArg) {
   NameVals.push_back(args.size());
-  NameVals.insert(NameVals.end(), args.begin(), args.end());
+  llvm::append_range(NameVals, args);
 
   NameVals.push_back(ByArg.TheKind);
   NameVals.push_back(ByArg.Info);
diff --git a/lib/Bitstream/Reader/BitstreamReader.cpp b/lib/Bitstream/Reader/BitstreamReader.cpp
index 1d4f045efee..28adfe6268f 100644
--- a/lib/Bitstream/Reader/BitstreamReader.cpp
+++ b/lib/Bitstream/Reader/BitstreamReader.cpp
@@ -27,8 +27,7 @@ Error BitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
   if (BlockInfo) {
     if (const BitstreamBlockInfo::BlockInfo *Info =
             BlockInfo->getBlockInfo(BlockID)) {
-      CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
-                        Info->Abbrevs.end());
+      llvm::append_range(CurAbbrevs, Info->Abbrevs);
     }
   }
 
diff --git a/lib/DWARFLinker/DWARFLinker.cpp b/lib/DWARFLinker/DWARFLinker.cpp
index 7acf9023c08..e285773dfd5 100644
--- a/lib/DWARFLinker/DWARFLinker.cpp
+++ b/lib/DWARFLinker/DWARFLinker.cpp
@@ -1575,7 +1575,7 @@ static void insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq,
     return;
 
   if (!Rows.empty() && Rows.back().Address < Seq.front().Address) {
-    Rows.insert(Rows.end(), Seq.begin(), Seq.end());
+    llvm::append_range(Rows, Seq);
     Seq.clear();
     return;
   }
diff --git a/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp b/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp
index cb1b35d6238..3aa77557862 100644
--- a/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp
+++ b/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp
@@ -419,7 +419,7 @@ static GenericValue lle_X_printf(FunctionType *FT,
   char Buffer[10000];
   std::vector<GenericValue> NewArgs;
   NewArgs.push_back(PTOGV((void*)&Buffer[0]));
-  NewArgs.insert(NewArgs.end(), Args.begin(), Args.end());
+  llvm::append_range(NewArgs, Args);
   GenericValue GV = lle_X_sprintf(FT, NewArgs);
   outs() << Buffer;
   return GV;
diff --git a/lib/ExecutionEngine/Orc/Core.cpp b/lib/ExecutionEngine/Orc/Core.cpp
index 659dd9a1d3e..7d61a7d6edd 100644
--- a/lib/ExecutionEngine/Orc/Core.cpp
+++ b/lib/ExecutionEngine/Orc/Core.cpp
@@ -1241,8 +1241,7 @@ void JITDylib::setLinkOrder(JITDylibSearchOrder NewLinkOrder,
       if (NewLinkOrder.empty() || NewLinkOrder.front().first != this)
         LinkOrder.push_back(
             std::make_pair(this, JITDylibLookupFlags::MatchAllSymbols));
-      LinkOrder.insert(LinkOrder.end(), NewLinkOrder.begin(),
-                       NewLinkOrder.end());
+      llvm::append_range(LinkOrder, NewLinkOrder);
     } else
       LinkOrder = std::move(NewLinkOrder);
   });
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index d39cdf7db04..ec2b83f614d 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -1200,7 +1200,7 @@ AttributeList AttributeList::get(LLVMContext &C, AttributeSet FnAttrs,
   if (NumSets > 2) {
     // Drop the empty argument attribute sets at the end.
     ArgAttrs = ArgAttrs.take_front(NumSets - 2);
-    AttrSets.insert(AttrSets.end(), ArgAttrs.begin(), ArgAttrs.end());
+    llvm::append_range(AttrSets, ArgAttrs);
   }
 
   return getImpl(C, AttrSets);
diff --git a/lib/IR/IRBuilder.cpp b/lib/IR/IRBuilder.cpp
index 51e28916559..e3aa9b3cf1f 100644
--- a/lib/IR/IRBuilder.cpp
+++ b/lib/IR/IRBuilder.cpp
@@ -578,7 +578,7 @@ getStatepointArgs(IRBuilderBase &B, uint64_t ID, uint32_t NumPatchBytes,
   Args.push_back(ActualCallee);
   Args.push_back(B.getInt32(CallArgs.size()));
   Args.push_back(B.getInt32(Flags));
-  Args.insert(Args.end(), CallArgs.begin(), CallArgs.end());
+  llvm::append_range(Args, CallArgs);
   // GC Transition and Deopt args are now always handled via operand bundle.
   // They will be removed from the signature of gc.statepoint shortly.
   Args.push_back(B.getInt32(0));
@@ -595,18 +595,17 @@ getStatepointBundles(Optional<ArrayRef<T1>> TransitionArgs,
   std::vector<OperandBundleDef> Rval;
   if (DeoptArgs) {
     SmallVector<Value*, 16> DeoptValues;
-    DeoptValues.insert(DeoptValues.end(), DeoptArgs->begin(), DeoptArgs->end());
+    llvm::append_range(DeoptValues, *DeoptArgs);
     Rval.emplace_back("deopt", DeoptValues);
   }
   if (TransitionArgs) {
     SmallVector<Value*, 16> TransitionValues;
-    TransitionValues.insert(TransitionValues.end(),
-                            TransitionArgs->begin(), TransitionArgs->end());
+    llvm::append_range(TransitionValues, *TransitionArgs);
     Rval.emplace_back("gc-transition", TransitionValues);
   }
   if (GCArgs.size()) {
     SmallVector<Value*, 16> LiveValues;
-    LiveValues.insert(LiveValues.end(), GCArgs.begin(), GCArgs.end());
+    llvm::append_range(LiveValues, GCArgs);
     Rval.emplace_back("gc-live", LiveValues);
   }
   return Rval;
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 5b9039d9a78..98241bc76ed 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -5975,7 +5975,7 @@ bool AsmParser::parseMSInlineAsm(
     // Consider implicit defs to be clobbers.  Think of cpuid and push.
     ArrayRef<MCPhysReg> ImpDefs(Desc.getImplicitDefs(),
                                 Desc.getNumImplicitDefs());
-    ClobberRegs.insert(ClobberRegs.end(), ImpDefs.begin(), ImpDefs.end());
+    llvm::append_range(ClobberRegs, ImpDefs);
   }
 
   // Set the number of Outputs and Inputs.
diff --git a/lib/MC/MCParser/MasmParser.cpp b/lib/MC/MCParser/MasmParser.cpp
index e5d8039f5f3..4957ee7a032 100644
--- a/lib/MC/MCParser/MasmParser.cpp
+++ b/lib/MC/MCParser/MasmParser.cpp
@@ -4044,8 +4044,7 @@ bool MasmParser::parseStructInstList(
         return true;
 
       for (int i = 0; i < Repetitions; ++i)
-        Initializers.insert(Initializers.end(), DuplicatedValues.begin(),
-                            DuplicatedValues.end());
+        llvm::append_range(Initializers, DuplicatedValues);
     } else {
       Initializers.emplace_back();
       if (parseStructInitializer(Structure, Initializers.back()))
@@ -7119,7 +7118,7 @@ bool MasmParser::parseMSInlineAsm(
     // Consider implicit defs to be clobbers.  Think of cpuid and push.
     ArrayRef<MCPhysReg> ImpDefs(Desc.getImplicitDefs(),
                                 Desc.getNumImplicitDefs());
-    ClobberRegs.insert(ClobberRegs.end(), ImpDefs.begin(), ImpDefs.end());
+    llvm::append_range(ClobberRegs, ImpDefs);
   }
 
   // Set the number of Outputs and Inputs.
diff --git a/lib/MC/WasmObjectWriter.cpp b/lib/MC/WasmObjectWriter.cpp
index 112c5b3f120..fb41c3763c1 100644
--- a/lib/MC/WasmObjectWriter.cpp
+++ b/lib/MC/WasmObjectWriter.cpp
@@ -649,11 +649,11 @@ static void addData(SmallVectorImpl<char> &DataBytes,
                        Fill->getValue());
     } else if (auto *LEB = dyn_cast<MCLEBFragment>(&Frag)) {
       const SmallVectorImpl<char> &Contents = LEB->getContents();
-      DataBytes.insert(DataBytes.end(), Contents.begin(), Contents.end());
+      llvm::append_range(DataBytes, Contents);
     } else {
       const auto &DataFrag = cast<MCDataFragment>(Frag);
       const SmallVectorImpl<char> &Contents = DataFrag.getContents();
-      DataBytes.insert(DataBytes.end(), Contents.begin(), Contents.end());
+      llvm::append_range(DataBytes, Contents);
     }
   }
 
diff --git a/lib/MCA/HardwareUnits/Scheduler.cpp b/lib/MCA/HardwareUnits/Scheduler.cpp
index 8730336c666..31ea751f1c4 100644
--- a/lib/MCA/HardwareUnits/Scheduler.cpp
+++ b/lib/MCA/HardwareUnits/Scheduler.cpp
@@ -241,7 +241,7 @@ void Scheduler::updateIssuedSet(SmallVectorImpl<InstRef> &Executed) {
 }
 
 uint64_t Scheduler::analyzeResourcePressure(SmallVectorImpl<InstRef> &Insts) {
-  Insts.insert(Insts.end(), ReadySet.begin(), ReadySet.end());
+  llvm::append_range(Insts, ReadySet);
   return BusyResourceUnits;
 }
 
diff --git a/lib/ProfileData/Coverage/CoverageMapping.cpp b/lib/ProfileData/Coverage/CoverageMapping.cpp
index 4c90eaafcc3..a8cc308b4e3 100644
--- a/lib/ProfileData/Coverage/CoverageMapping.cpp
+++ b/lib/ProfileData/Coverage/CoverageMapping.cpp
@@ -616,8 +616,7 @@ public:
 std::vector<StringRef> CoverageMapping::getUniqueSourceFiles() const {
   std::vector<StringRef> Filenames;
   for (const auto &Function : getCoveredFunctions())
-    Filenames.insert(Filenames.end(), Function.Filenames.begin(),
-                     Function.Filenames.end());
+    llvm::append_range(Filenames, Function.Filenames);
   llvm::sort(Filenames);
   auto Last = std::unique(Filenames.begin(), Filenames.end());
   Filenames.erase(Last, Filenames.end());
diff --git a/lib/ProfileData/SampleProfReader.cpp b/lib/ProfileData/SampleProfReader.cpp
index ebae9cee955..a8ffb378fb3 100644
--- a/lib/ProfileData/SampleProfReader.cpp
+++ b/lib/ProfileData/SampleProfReader.cpp
@@ -1349,7 +1349,7 @@ std::error_code SampleProfileReaderGCC::readOneFunctionProfile(
 
     InlineCallStack NewStack;
     NewStack.push_back(FProfile);
-    NewStack.insert(NewStack.end(), InlineStack.begin(), InlineStack.end());
+    llvm::append_range(NewStack, InlineStack);
     if (Update) {
       // Walk up the inline stack, adding the samples on this line to
       // the total sample count of the callers in the chain.
@@ -1397,7 +1397,7 @@ std::error_code SampleProfileReaderGCC::readOneFunctionProfile(
       return sampleprof_error::truncated;
     InlineCallStack NewStack;
     NewStack.push_back(FProfile);
-    NewStack.insert(NewStack.end(), InlineStack.begin(), InlineStack.end());
+    llvm::append_range(NewStack, InlineStack);
     if (std::error_code EC = readOneFunctionProfile(NewStack, Update, Offset))
       return EC;
   }
diff --git a/lib/Support/Windows/Program.inc b/lib/Support/Windows/Program.inc
index 36840016db3..91df4488850 100644
--- a/lib/Support/Windows/Program.inc
+++ b/lib/Support/Windows/Program.inc
@@ -212,7 +212,7 @@ static bool Execute(ProcessInfo &PI, StringRef Program,
         return false;
       }
 
-      EnvBlock.insert(EnvBlock.end(), EnvString.begin(), EnvString.end());
+      llvm::append_range(EnvBlock, EnvString);
       EnvBlock.push_back(0);
     }
     EnvBlock.push_back(0);
diff --git a/lib/Support/YAMLParser.cpp b/lib/Support/YAMLParser.cpp
index d037cdf850e..17321177105 100644
--- a/lib/Support/YAMLParser.cpp
+++ b/lib/Support/YAMLParser.cpp
@@ -715,7 +715,7 @@ std::string yaml::escape(StringRef Input, bool EscapePrintable) {
         // Found invalid char.
         SmallString<4> Val;
         encodeUTF8(0xFFFD, Val);
-        EscapedInput.insert(EscapedInput.end(), Val.begin(), Val.end());
+        llvm::append_range(EscapedInput, Val);
         // FIXME: Error reporting.
         return EscapedInput;
       }
@@ -1984,11 +1984,11 @@ StringRef ScalarNode::getValue(SmallVectorImpl<char> &Storage) const {
       Storage.reserve(UnquotedValue.size());
       for (; i != StringRef::npos; i = UnquotedValue.find('\'')) {
         StringRef Valid(UnquotedValue.begin(), i);
-        Storage.insert(Storage.end(), Valid.begin(), Valid.end());
+        llvm::append_range(Storage, Valid);
         Storage.push_back('\'');
         UnquotedValue = UnquotedValue.substr(i + 2);
       }
-      Storage.insert(Storage.end(), UnquotedValue.begin(), UnquotedValue.end());
+      llvm::append_range(Storage, UnquotedValue);
       return StringRef(Storage.begin(), Storage.size());
     }
     return UnquotedValue;
@@ -2007,7 +2007,7 @@ StringRef ScalarNode::unescapeDoubleQuoted( StringRef UnquotedValue
   for (; i != StringRef::npos; i = UnquotedValue.find_first_of("\\\r\n")) {
     // Insert all previous chars into Storage.
     StringRef Valid(UnquotedValue.begin(), i);
-    Storage.insert(Storage.end(), Valid.begin(), Valid.end());
+    llvm::append_range(Storage, Valid);
     // Chop off inserted chars.
     UnquotedValue = UnquotedValue.substr(i);
 
@@ -2139,7 +2139,7 @@ StringRef ScalarNode::unescapeDoubleQuoted( StringRef UnquotedValue
       UnquotedValue = UnquotedValue.substr(1);
     }
   }
-  Storage.insert(Storage.end(), UnquotedValue.begin(), UnquotedValue.end());
+  llvm::append_range(Storage, UnquotedValue);
   return StringRef(Storage.begin(), Storage.size());
 }
 
diff --git a/lib/TableGen/Record.cpp b/lib/TableGen/Record.cpp
index afd72549d69..6b19454e95d 100644
--- a/lib/TableGen/Record.cpp
+++ b/lib/TableGen/Record.cpp
@@ -905,8 +905,8 @@ Init *BinOpInit::getStrConcat(Init *I0, Init *I1) {
 static ListInit *ConcatListInits(const ListInit *LHS,
                                  const ListInit *RHS) {
   SmallVector<Init *, 8> Args;
-  Args.insert(Args.end(), LHS->begin(), LHS->end());
-  Args.insert(Args.end(), RHS->begin(), RHS->end());
+  llvm::append_range(Args, *LHS);
+  llvm::append_range(Args, *RHS);
   return ListInit::get(Args, LHS->getElementType());
 }
 
@@ -959,8 +959,8 @@ Init *BinOpInit::Fold(Record *CurRec) const {
     ListInit *RHSs = dyn_cast<ListInit>(RHS);
     if (LHSs && RHSs) {
       SmallVector<Init *, 8> Args;
-      Args.insert(Args.end(), LHSs->begin(), LHSs->end());
-      Args.insert(Args.end(), RHSs->begin(), RHSs->end());
+      llvm::append_range(Args, *LHSs);
+      llvm::append_range(Args, *RHSs);
       return ListInit::get(Args, LHSs->getElementType());
     }
     break;