diff --git a/include/llvm/Bitcode/BitstreamReader.h b/include/llvm/Bitcode/BitstreamReader.h
index fcbf4260441..6f478b72127 100644
--- a/include/llvm/Bitcode/BitstreamReader.h
+++ b/include/llvm/Bitcode/BitstreamReader.h
@@ -111,7 +111,7 @@ public:
          i != e; ++i)
       if (BlockInfoRecords[i].BlockID == BlockID)
         return &BlockInfoRecords[i];
-    return 0;
+    return nullptr;
   }
 
   BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
@@ -200,9 +200,9 @@ class BitstreamCursor {
 
 
 public:
-  BitstreamCursor() : BitStream(0), NextChar(0) {
-  }
-  BitstreamCursor(const BitstreamCursor &RHS) : BitStream(0), NextChar(0) {
+  BitstreamCursor() : BitStream(nullptr), NextChar(0) {}
+  BitstreamCursor(const BitstreamCursor &RHS)
+      : BitStream(nullptr), NextChar(0) {
     operator=(RHS);
   }
 
@@ -490,7 +490,7 @@ public:
 
   /// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
   /// the block, and return true if the block has an error.
-  bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = 0);
+  bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
 
   bool ReadBlockEnd() {
     if (BlockScope.empty()) return true;
@@ -541,7 +541,7 @@ public:
   void skipRecord(unsigned AbbrevID);
 
   unsigned readRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
-                      StringRef *Blob = 0);
+                      StringRef *Blob = nullptr);
 
   //===--------------------------------------------------------------------===//
   // Abbrev Processing
diff --git a/include/llvm/Bitcode/BitstreamWriter.h b/include/llvm/Bitcode/BitstreamWriter.h
index ef88a88a6cd..dcfebd9cc10 100644
--- a/include/llvm/Bitcode/BitstreamWriter.h
+++ b/include/llvm/Bitcode/BitstreamWriter.h
@@ -204,7 +204,7 @@ public:
          i != e; ++i)
       if (BlockInfoRecords[i].BlockID == BlockID)
         return &BlockInfoRecords[i];
-    return 0;
+    return nullptr;
   }
 
   void EnterSubblock(unsigned BlockID, unsigned CodeLen) {
@@ -347,7 +347,7 @@ private:
             EmitAbbreviatedField(EltEnc, (unsigned char)BlobData[i]);
 
           // Know that blob data is consumed for assertion below.
-          BlobData = 0;
+          BlobData = nullptr;
         } else {
           // Emit a vbr6 to indicate the number of elements present.
           EmitVBR(static_cast<uint32_t>(Vals.size()-RecordIdx), 6);
@@ -378,7 +378,7 @@ private:
             WriteByte((unsigned char)BlobData[i]);
 
           // Know that blob data is consumed for assertion below.
-          BlobData = 0;
+          BlobData = nullptr;
         } else {
           for (unsigned e = Vals.size(); RecordIdx != e; ++RecordIdx) {
             assert(isUInt<8>(Vals[RecordIdx]) &&
@@ -397,7 +397,7 @@ private:
       }
     }
     assert(RecordIdx == Vals.size() && "Not all record operands emitted!");
-    assert(BlobData == 0 &&
+    assert(BlobData == nullptr &&
            "Blob data specified for record that doesn't use it!");
   }
 
diff --git a/include/llvm/CodeGen/FunctionLoweringInfo.h b/include/llvm/CodeGen/FunctionLoweringInfo.h
index 06e7aaaf22d..9636b51e303 100644
--- a/include/llvm/CodeGen/FunctionLoweringInfo.h
+++ b/include/llvm/CodeGen/FunctionLoweringInfo.h
@@ -153,11 +153,11 @@ public:
   /// register is a PHI destination and the PHI's LiveOutInfo is not valid.
   const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) {
     if (!LiveOutRegInfo.inBounds(Reg))
-      return NULL;
+      return nullptr;
 
     const LiveOutInfo *LOI = &LiveOutRegInfo[Reg];
     if (!LOI->IsValid)
-      return NULL;
+      return nullptr;
 
     return LOI;
   }
diff --git a/include/llvm/CodeGen/ResourcePriorityQueue.h b/include/llvm/CodeGen/ResourcePriorityQueue.h
index 7ae9111028e..114fe7c35b8 100644
--- a/include/llvm/CodeGen/ResourcePriorityQueue.h
+++ b/include/llvm/CodeGen/ResourcePriorityQueue.h
@@ -92,7 +92,7 @@ namespace llvm {
     void updateNode(const SUnit *SU) override {}
 
     void releaseState() override {
-      SUnits = 0;
+      SUnits = nullptr;
     }
 
     unsigned getLatency(unsigned NodeNum) const {
diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index 8819d9d7777..b1e63f29a22 100644
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -578,7 +578,7 @@ public:
     Ops.push_back(Op2);
     Ops.push_back(InGlue);
     return getNode(ISD::CALLSEQ_END, DL, NodeTys, &Ops[0],
-                   (unsigned)Ops.size() - (InGlue.getNode() == 0 ? 1 : 0));
+                   (unsigned)Ops.size() - (InGlue.getNode()==nullptr ? 1 : 0));
   }
 
   /// getUNDEF - Return an UNDEF node.  UNDEF does not have a useful SDLoc.
@@ -766,14 +766,15 @@ public:
   SDValue getLoad(EVT VT, SDLoc dl, SDValue Chain, SDValue Ptr,
                   MachinePointerInfo PtrInfo, bool isVolatile,
                   bool isNonTemporal, bool isInvariant, unsigned Alignment,
-                  const MDNode *TBAAInfo = 0, const MDNode *Ranges = 0);
+                  const MDNode *TBAAInfo = nullptr,
+                  const MDNode *Ranges = nullptr);
   SDValue getLoad(EVT VT, SDLoc dl, SDValue Chain, SDValue Ptr,
                   MachineMemOperand *MMO);
   SDValue getExtLoad(ISD::LoadExtType ExtType, SDLoc dl, EVT VT,
                      SDValue Chain, SDValue Ptr, MachinePointerInfo PtrInfo,
                      EVT MemVT, bool isVolatile,
                      bool isNonTemporal, unsigned Alignment,
-                     const MDNode *TBAAInfo = 0);
+                     const MDNode *TBAAInfo = nullptr);
   SDValue getExtLoad(ISD::LoadExtType ExtType, SDLoc dl, EVT VT,
                      SDValue Chain, SDValue Ptr, EVT MemVT,
                      MachineMemOperand *MMO);
@@ -784,8 +785,8 @@ public:
                   SDValue Chain, SDValue Ptr, SDValue Offset,
                   MachinePointerInfo PtrInfo, EVT MemVT,
                   bool isVolatile, bool isNonTemporal, bool isInvariant,
-                  unsigned Alignment, const MDNode *TBAAInfo = 0,
-                  const MDNode *Ranges = 0);
+                  unsigned Alignment, const MDNode *TBAAInfo = nullptr,
+                  const MDNode *Ranges = nullptr);
   SDValue getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType,
                   EVT VT, SDLoc dl,
                   SDValue Chain, SDValue Ptr, SDValue Offset,
@@ -796,14 +797,14 @@ public:
   SDValue getStore(SDValue Chain, SDLoc dl, SDValue Val, SDValue Ptr,
                    MachinePointerInfo PtrInfo, bool isVolatile,
                    bool isNonTemporal, unsigned Alignment,
-                   const MDNode *TBAAInfo = 0);
+                   const MDNode *TBAAInfo = nullptr);
   SDValue getStore(SDValue Chain, SDLoc dl, SDValue Val, SDValue Ptr,
                    MachineMemOperand *MMO);
   SDValue getTruncStore(SDValue Chain, SDLoc dl, SDValue Val, SDValue Ptr,
                         MachinePointerInfo PtrInfo, EVT TVT,
                         bool isNonTemporal, bool isVolatile,
                         unsigned Alignment,
-                        const MDNode *TBAAInfo = 0);
+                        const MDNode *TBAAInfo = nullptr);
   SDValue getTruncStore(SDValue Chain, SDLoc dl, SDValue Val, SDValue Ptr,
                         EVT TVT, MachineMemOperand *MMO);
   SDValue getIndexedStore(SDValue OrigStoe, SDLoc dl, SDValue Base,
diff --git a/include/llvm/DebugInfo/DWARFFormValue.h b/include/llvm/DebugInfo/DWARFFormValue.h
index 533d2593b18..d517a72d62e 100644
--- a/include/llvm/DebugInfo/DWARFFormValue.h
+++ b/include/llvm/DebugInfo/DWARFFormValue.h
@@ -36,7 +36,7 @@ public:
 
 private:
   struct ValueType {
-    ValueType() : data(NULL) {
+    ValueType() : data(nullptr) {
       uval = 0;
     }
 
@@ -60,7 +60,7 @@ public:
   bool extractValue(DataExtractor data, uint32_t *offset_ptr,
                     const DWARFUnit *u);
   bool isInlinedCStr() const {
-    return Value.data != NULL && Value.data == (const uint8_t*)Value.cstr;
+    return Value.data != nullptr && Value.data == (const uint8_t*)Value.cstr;
   }
 
   /// getAsFoo functions below return the extracted value as Foo if only
diff --git a/include/llvm/ExecutionEngine/ExecutionEngine.h b/include/llvm/ExecutionEngine/ExecutionEngine.h
index 4dca870bec7..5bd34e85560 100644
--- a/include/llvm/ExecutionEngine/ExecutionEngine.h
+++ b/include/llvm/ExecutionEngine/ExecutionEngine.h
@@ -181,7 +181,7 @@ public:
   /// freeMachineCodeForFunction works.
   static ExecutionEngine *create(Module *M,
                                  bool ForceInterpreter = false,
-                                 std::string *ErrorStr = 0,
+                                 std::string *ErrorStr = nullptr,
                                  CodeGenOpt::Level OptLevel =
                                  CodeGenOpt::Default,
                                  bool GVsWithCode = true);
@@ -193,8 +193,8 @@ public:
   /// Clients should make sure to initialize targets prior to calling this
   /// function.
   static ExecutionEngine *createJIT(Module *M,
-                                    std::string *ErrorStr = 0,
-                                    JITMemoryManager *JMM = 0,
+                                    std::string *ErrorStr = nullptr,
+                                    JITMemoryManager *JMM = nullptr,
                                     CodeGenOpt::Level OptLevel =
                                     CodeGenOpt::Default,
                                     bool GVsWithCode = true,
@@ -411,7 +411,7 @@ public:
   }
 
   // The JIT overrides a version that actually does this.
-  virtual void runJITOnFunction(Function *, MachineCodeInfo * = 0) { }
+  virtual void runJITOnFunction(Function *, MachineCodeInfo * = nullptr) { }
 
   /// getGlobalValueAtAddress - Return the LLVM global value object that starts
   /// at the specified address.
@@ -478,7 +478,7 @@ public:
   }
 
   /// Return the target machine (if available).
-  virtual TargetMachine *getTargetMachine() { return NULL; }
+  virtual TargetMachine *getTargetMachine() { return nullptr; }
 
   /// DisableLazyCompilation - When lazy compilation is off (the default), the
   /// JIT will eagerly compile every function reachable from the argument to
@@ -576,10 +576,10 @@ private:
   /// InitEngine - Does the common initialization of default options.
   void InitEngine() {
     WhichEngine = EngineKind::Either;
-    ErrorStr = NULL;
+    ErrorStr = nullptr;
     OptLevel = CodeGenOpt::Default;
-    MCJMM = NULL;
-    JMM = NULL;
+    MCJMM = nullptr;
+    JMM = nullptr;
     Options = TargetOptions();
     AllocateGVsWithCode = false;
     RelocModel = Reloc::Default;
@@ -610,7 +610,7 @@ public:
   /// the setJITMemoryManager() option.
   EngineBuilder &setMCJITMemoryManager(RTDyldMemoryManager *mcjmm) {
     MCJMM = mcjmm;
-    JMM = NULL;
+    JMM = nullptr;
     return *this;
   }
 
@@ -622,7 +622,7 @@ public:
   /// memory manager.  This option defaults to NULL. This option overrides
   /// setMCJITMemoryManager() as well.
   EngineBuilder &setJITMemoryManager(JITMemoryManager *jmm) {
-    MCJMM = NULL;
+    MCJMM = nullptr;
     JMM = jmm;
     return *this;
   }
diff --git a/include/llvm/ExecutionEngine/RTDyldMemoryManager.h b/include/llvm/ExecutionEngine/RTDyldMemoryManager.h
index 70dd1cbe714..b1d6810f374 100644
--- a/include/llvm/ExecutionEngine/RTDyldMemoryManager.h
+++ b/include/llvm/ExecutionEngine/RTDyldMemoryManager.h
@@ -114,7 +114,7 @@ public:
   /// operations needed to reliably use the memory are also performed.
   ///
   /// Returns true if an error occurred, false otherwise.
-  virtual bool finalizeMemory(std::string *ErrMsg = 0) = 0;
+  virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
 };
 
 // Create wrappers for C Binding types (see CBindingWrapping.h).
diff --git a/include/llvm/IR/LegacyPassNameParser.h b/include/llvm/IR/LegacyPassNameParser.h
index ec8671082dc..b72fc4c1a11 100644
--- a/include/llvm/IR/LegacyPassNameParser.h
+++ b/include/llvm/IR/LegacyPassNameParser.h
@@ -73,7 +73,7 @@ public:
     if (findOption(P->getPassArgument()) != getNumOptions()) {
       errs() << "Two passes with the same argument (-"
            << P->getPassArgument() << ") attempted to be registered!\n";
-      llvm_unreachable(0);
+      llvm_unreachable(nullptr);
     }
     addLiteralOption(P->getPassArgument(), P, P->getPassName());
   }
diff --git a/include/llvm/LTO/LTOModule.h b/include/llvm/LTO/LTOModule.h
index 1e4fa1b7b22..683985a13c3 100644
--- a/include/llvm/LTO/LTOModule.h
+++ b/include/llvm/LTO/LTOModule.h
@@ -129,7 +129,7 @@ public:
   const char *getSymbolName(uint32_t index) {
     if (index < _symbols.size())
       return _symbols[index].name;
-    return NULL;
+    return nullptr;
   }
 
   /// getDependentLibraryCount - Get the number of dependent libraries
@@ -141,7 +141,7 @@ public:
   const char *getDependentLibrary(uint32_t index) {
     if (index < _deplibs.size())
       return _deplibs[index];
-    return NULL;
+    return nullptr;
   }
 
   /// getLinkerOptCount - Get the number of linker options
@@ -153,7 +153,7 @@ public:
   const char *getLinkerOpt(uint32_t index) {
     if (index < _linkeropts.size())
       return _linkeropts[index];
-    return NULL;
+    return nullptr;
   }
 
   /// getLLVVMModule - Return the Module.
diff --git a/include/llvm/MC/MCParser/AsmLexer.h b/include/llvm/MC/MCParser/AsmLexer.h
index f36011c9ff9..59b5c09b402 100644
--- a/include/llvm/MC/MCParser/AsmLexer.h
+++ b/include/llvm/MC/MCParser/AsmLexer.h
@@ -42,7 +42,7 @@ public:
   AsmLexer(const MCAsmInfo &MAI);
   ~AsmLexer();
 
-  void setBuffer(const MemoryBuffer *buf, const char *ptr = NULL);
+  void setBuffer(const MemoryBuffer *buf, const char *ptr = nullptr);
 
   StringRef LexUntilEndOfStatement() override;
   StringRef LexUntilEndOfLine();
diff --git a/include/llvm/MC/MCParser/MCAsmParser.h b/include/llvm/MC/MCParser/MCAsmParser.h
index 0389caa0545..f751786a8eb 100644
--- a/include/llvm/MC/MCParser/MCAsmParser.h
+++ b/include/llvm/MC/MCParser/MCAsmParser.h
@@ -39,7 +39,7 @@ public:
     unsigned Length, Size, Type;
 
     void clear() {
-      OpDecl = 0;
+      OpDecl = nullptr;
       IsVarDecl = false;
       Length = 1;
       Size = 0;
diff --git a/include/llvm/MC/MCTargetAsmParser.h b/include/llvm/MC/MCTargetAsmParser.h
index 0073136015c..79328bec9f3 100644
--- a/include/llvm/MC/MCTargetAsmParser.h
+++ b/include/llvm/MC/MCTargetAsmParser.h
@@ -63,7 +63,7 @@ struct ParseInstructionInfo {
 
   SmallVectorImpl<AsmRewrite> *AsmRewrites;
 
-  ParseInstructionInfo() : AsmRewrites(0) {}
+  ParseInstructionInfo() : AsmRewrites(nullptr) {}
   ParseInstructionInfo(SmallVectorImpl<AsmRewrite> *rewrites)
     : AsmRewrites(rewrites) {}
 
@@ -179,7 +179,7 @@ public:
   virtual const MCExpr *applyModifierToExpr(const MCExpr *E,
                                             MCSymbolRefExpr::VariantKind,
                                             MCContext &Ctx) {
-    return 0;
+    return nullptr;
   }
 
   virtual void onLabelParsed(MCSymbol *Symbol) { };
diff --git a/include/llvm/Object/Archive.h b/include/llvm/Object/Archive.h
index 4fae76fdd52..a73b13e0503 100644
--- a/include/llvm/Object/Archive.h
+++ b/include/llvm/Object/Archive.h
@@ -95,15 +95,15 @@ public:
                                bool FullPath = false) const;
 
     error_code getAsBinary(OwningPtr<Binary> &Result,
-                           LLVMContext *Context = 0) const;
+                           LLVMContext *Context = nullptr) const;
     error_code getAsBinary(std::unique_ptr<Binary> &Result,
-                           LLVMContext *Context = 0) const;
+                           LLVMContext *Context = nullptr) const;
   };
 
   class child_iterator {
     Child child;
   public:
-    child_iterator() : child(Child(0, 0)) {}
+    child_iterator() : child(Child(nullptr, nullptr)) {}
     child_iterator(const Child &c) : child(c) {}
     const Child* operator->() const {
       return &child;
diff --git a/include/llvm/Object/COFF.h b/include/llvm/Object/COFF.h
index 43dc2c8bda7..bd9c67740df 100644
--- a/include/llvm/Object/COFF.h
+++ b/include/llvm/Object/COFF.h
@@ -464,7 +464,7 @@ public:
 // The iterator for the import directory table.
 class ImportDirectoryEntryRef {
 public:
-  ImportDirectoryEntryRef() : OwningObject(0) {}
+  ImportDirectoryEntryRef() : OwningObject(nullptr) {}
   ImportDirectoryEntryRef(const import_directory_table_entry *Table, uint32_t I,
                           const COFFObjectFile *Owner)
       : ImportTable(Table), Index(I), OwningObject(Owner) {}
@@ -488,7 +488,7 @@ private:
 // The iterator for the export directory table entry.
 class ExportDirectoryEntryRef {
 public:
-  ExportDirectoryEntryRef() : OwningObject(0) {}
+  ExportDirectoryEntryRef() : OwningObject(nullptr) {}
   ExportDirectoryEntryRef(const export_directory_table_entry *Table, uint32_t I,
                           const COFFObjectFile *Owner)
       : ExportTable(Table), Index(I), OwningObject(Owner) {}
diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h
index 765db82ed51..2572a4e279c 100644
--- a/include/llvm/Object/ELF.h
+++ b/include/llvm/Object/ELF.h
@@ -604,14 +604,14 @@ typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
 template <class ELFT>
 ELFFile<ELFT>::ELFFile(MemoryBuffer *Object, error_code &ec)
     : Buf(Object),
-      SectionHeaderTable(0),
-      dot_shstrtab_sec(0),
-      dot_strtab_sec(0),
-      dot_symtab_sec(0),
-      SymbolTableSectionHeaderIndex(0),
-      dot_gnu_version_sec(0),
-      dot_gnu_version_r_sec(0),
-      dot_gnu_version_d_sec(0),
+      SectionHeaderTable(nullptr),
+      dot_shstrtab_sec(nullptr),
+      dot_strtab_sec(nullptr),
+      dot_symtab_sec(nullptr),
+      SymbolTableSectionHeaderIndex(nullptr),
+      dot_gnu_version_sec(nullptr),
+      dot_gnu_version_r_sec(nullptr),
+      dot_gnu_version_d_sec(nullptr),
       dt_soname(nullptr) {
   const uint64_t FileSize = Buf->getBufferSize();
 
@@ -679,19 +679,19 @@ ELFFile<ELFT>::ELFFile(MemoryBuffer *Object, error_code &ec)
       DynamicRegion.EntSize = SecI->sh_entsize;
       break;
     case ELF::SHT_GNU_versym:
-      if (dot_gnu_version_sec != NULL)
+      if (dot_gnu_version_sec != nullptr)
         // FIXME: Proper error handling.
         report_fatal_error("More than one .gnu.version section!");
       dot_gnu_version_sec = &*SecI;
       break;
     case ELF::SHT_GNU_verdef:
-      if (dot_gnu_version_d_sec != NULL)
+      if (dot_gnu_version_d_sec != nullptr)
         // FIXME: Proper error handling.
         report_fatal_error("More than one .gnu.version_d section!");
       dot_gnu_version_d_sec = &*SecI;
       break;
     case ELF::SHT_GNU_verneed:
-      if (dot_gnu_version_r_sec != NULL)
+      if (dot_gnu_version_r_sec != nullptr)
         // FIXME: Proper error handling.
         report_fatal_error("More than one .gnu.version_r section!");
       dot_gnu_version_r_sec = &*SecI;
@@ -769,7 +769,7 @@ typename ELFFile<ELFT>::Elf_Sym_Iter ELFFile<ELFT>::begin_symbols() const {
 template <class ELFT>
 typename ELFFile<ELFT>::Elf_Sym_Iter ELFFile<ELFT>::end_symbols() const {
   if (!dot_symtab_sec)
-    return Elf_Sym_Iter(0, 0, false);
+    return Elf_Sym_Iter(0, nullptr, false);
   return Elf_Sym_Iter(dot_symtab_sec->sh_entsize,
                       (const char *)base() + dot_symtab_sec->sh_offset +
                           dot_symtab_sec->sh_size,
@@ -782,14 +782,14 @@ ELFFile<ELFT>::begin_dynamic_table() const {
   if (DynamicRegion.Addr)
     return Elf_Dyn_Iter(DynamicRegion.EntSize,
                         (const char *)DynamicRegion.Addr);
-  return Elf_Dyn_Iter(0, 0);
+  return Elf_Dyn_Iter(0, nullptr);
 }
 
 template <class ELFT>
 typename ELFFile<ELFT>::Elf_Dyn_Iter
 ELFFile<ELFT>::end_dynamic_table(bool NULLEnd) const {
   if (!DynamicRegion.Addr)
-    return Elf_Dyn_Iter(0, 0);
+    return Elf_Dyn_Iter(0, nullptr);
   Elf_Dyn_Iter Ret(DynamicRegion.EntSize,
                     (const char *)DynamicRegion.Addr + DynamicRegion.Size);
 
diff --git a/include/llvm/Object/MachOUniversal.h b/include/llvm/Object/MachOUniversal.h
index 9b1afd2072e..da1445fd70a 100644
--- a/include/llvm/Object/MachOUniversal.h
+++ b/include/llvm/Object/MachOUniversal.h
@@ -41,7 +41,7 @@ public:
     ObjectForArch(const MachOUniversalBinary *Parent, uint32_t Index);
 
     void clear() {
-      Parent = 0;
+      Parent = nullptr;
       Index = 0;
     }
 
@@ -83,7 +83,7 @@ public:
     return ObjectForArch(this, 0);
   }
   object_iterator end_objects() const {
-    return ObjectForArch(0, 0);
+    return ObjectForArch(nullptr, 0);
   }
 
   uint32_t getNumberOfObjects() const { return NumberOfObjects; }
diff --git a/include/llvm/Option/Arg.h b/include/llvm/Option/Arg.h
index 6b8ed3f7d2b..eee4014a41b 100644
--- a/include/llvm/Option/Arg.h
+++ b/include/llvm/Option/Arg.h
@@ -63,11 +63,11 @@ private:
 
 public:
   Arg(const Option Opt, StringRef Spelling, unsigned Index,
-      const Arg *BaseArg = 0);
+      const Arg *BaseArg = nullptr);
   Arg(const Option Opt, StringRef Spelling, unsigned Index,
-      const char *Value0, const Arg *BaseArg = 0);
+      const char *Value0, const Arg *BaseArg = nullptr);
   Arg(const Option Opt, StringRef Spelling, unsigned Index,
-      const char *Value0, const char *Value1, const Arg *BaseArg = 0);
+      const char *Value0, const char *Value1, const Arg *BaseArg = nullptr);
   ~Arg();
 
   const Option getOption() const { return Opt; }
diff --git a/include/llvm/Option/ArgList.h b/include/llvm/Option/ArgList.h
index 98ba6ec10c9..6a51900d069 100644
--- a/include/llvm/Option/ArgList.h
+++ b/include/llvm/Option/ArgList.h
@@ -160,16 +160,16 @@ public:
   ///
   /// \p Claim Whether the argument should be claimed, if it exists.
   bool hasArgNoClaim(OptSpecifier Id) const {
-    return getLastArgNoClaim(Id) != 0;
+    return getLastArgNoClaim(Id) != nullptr;
   }
   bool hasArg(OptSpecifier Id) const {
-    return getLastArg(Id) != 0;
+    return getLastArg(Id) != nullptr;
   }
   bool hasArg(OptSpecifier Id0, OptSpecifier Id1) const {
-    return getLastArg(Id0, Id1) != 0;
+    return getLastArg(Id0, Id1) != nullptr;
   }
   bool hasArg(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2) const {
-    return getLastArg(Id0, Id1, Id2) != 0;
+    return getLastArg(Id0, Id1, Id2) != nullptr;
   }
 
   /// getLastArg - Return the last argument matching \p Id, or null.
diff --git a/include/llvm/Option/Option.h b/include/llvm/Option/Option.h
index 03d4774829f..b2cfacbaf34 100644
--- a/include/llvm/Option/Option.h
+++ b/include/llvm/Option/Option.h
@@ -73,7 +73,7 @@ public:
   ~Option();
 
   bool isValid() const {
-    return Info != 0;
+    return Info != nullptr;
   }
 
   unsigned getID() const {
diff --git a/include/llvm/Support/YAMLTraits.h b/include/llvm/Support/YAMLTraits.h
index 97ac0cdf9f5..d736b2637f1 100644
--- a/include/llvm/Support/YAMLTraits.h
+++ b/include/llvm/Support/YAMLTraits.h
@@ -194,7 +194,7 @@ struct has_ScalarBitSetTraits
   static double test(...);
 
 public:
-  static bool const value = (sizeof(test<ScalarBitSetTraits<T> >(0)) == 1);
+  static bool const value = (sizeof(test<ScalarBitSetTraits<T> >(nullptr)) == 1);
 };
 
 
@@ -778,7 +778,7 @@ struct ScalarTraits<double> {
 template <typename TNorm, typename TFinal>
 struct MappingNormalization {
   MappingNormalization(IO &i_o, TFinal &Obj)
-      : io(i_o), BufPtr(NULL), Result(Obj) {
+      : io(i_o), BufPtr(nullptr), Result(Obj) {
     if ( io.outputting() ) {
       BufPtr = new (&Buffer) TNorm(io, Obj);
     }
diff --git a/include/llvm/Target/TargetIntrinsicInfo.h b/include/llvm/Target/TargetIntrinsicInfo.h
index ce213496935..6de264e90ef 100644
--- a/include/llvm/Target/TargetIntrinsicInfo.h
+++ b/include/llvm/Target/TargetIntrinsicInfo.h
@@ -40,7 +40,7 @@ public:
   /// intrinsic, Tys should point to an array of numTys pointers to Type,
   /// and must provide exactly one type for each overloaded type in the
   /// intrinsic.
-  virtual std::string getName(unsigned IID, Type **Tys = 0,
+  virtual std::string getName(unsigned IID, Type **Tys = nullptr,
                               unsigned numTys = 0) const = 0;
 
   /// Look up target intrinsic by name. Return intrinsic ID or 0 for unknown
@@ -56,7 +56,7 @@ public:
   /// Create or insert an LLVM Function declaration for an intrinsic,
   /// and return it. The Tys and numTys are for intrinsics with overloaded
   /// types. See above for more information.
-  virtual Function *getDeclaration(Module *M, unsigned ID, Type **Tys = 0,
+  virtual Function *getDeclaration(Module *M, unsigned ID, Type **Tys = nullptr,
                                    unsigned numTys = 0) const = 0;
 };
 
diff --git a/include/llvm/Transforms/Utils/Cloning.h b/include/llvm/Transforms/Utils/Cloning.h
index 96c650834aa..03e156ed4be 100644
--- a/include/llvm/Transforms/Utils/Cloning.h
+++ b/include/llvm/Transforms/Utils/Cloning.h
@@ -96,8 +96,8 @@ struct ClonedCodeInfo {
 ///
 BasicBlock *CloneBasicBlock(const BasicBlock *BB,
                             ValueToValueMapTy &VMap,
-                            const Twine &NameSuffix = "", Function *F = 0,
-                            ClonedCodeInfo *CodeInfo = 0);
+                            const Twine &NameSuffix = "", Function *F = nullptr,
+                            ClonedCodeInfo *CodeInfo = nullptr);
 
 /// CloneFunction - Return a copy of the specified function, but without
 /// embedding the function into another module.  Also, any references specified
@@ -114,7 +114,7 @@ BasicBlock *CloneBasicBlock(const BasicBlock *BB,
 Function *CloneFunction(const Function *F,
                         ValueToValueMapTy &VMap,
                         bool ModuleLevelChanges,
-                        ClonedCodeInfo *CodeInfo = 0);
+                        ClonedCodeInfo *CodeInfo = nullptr);
 
 /// Clone OldFunc into NewFunc, transforming the old arguments into references
 /// to VMap values.  Note that if NewFunc already has basic blocks, the ones
@@ -130,9 +130,9 @@ void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
                        bool ModuleLevelChanges,
                        SmallVectorImpl<ReturnInst*> &Returns,
                        const char *NameSuffix = "", 
-                       ClonedCodeInfo *CodeInfo = 0,
-                       ValueMapTypeRemapper *TypeMapper = 0,
-                       ValueMaterializer *Materializer = 0);
+                       ClonedCodeInfo *CodeInfo = nullptr,
+                       ValueMapTypeRemapper *TypeMapper = nullptr,
+                       ValueMaterializer *Materializer = nullptr);
 
 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
 /// except that it does some simple constant prop and DCE on the fly.  The
@@ -150,16 +150,16 @@ void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
                                bool ModuleLevelChanges,
                                SmallVectorImpl<ReturnInst*> &Returns,
                                const char *NameSuffix = "", 
-                               ClonedCodeInfo *CodeInfo = 0,
-                               const DataLayout *DL = 0,
-                               Instruction *TheCall = 0);
+                               ClonedCodeInfo *CodeInfo = nullptr,
+                               const DataLayout *DL = nullptr,
+                               Instruction *TheCall = nullptr);
 
   
 /// InlineFunctionInfo - This class captures the data input to the
 /// InlineFunction call, and records the auxiliary results produced by it. 
 class InlineFunctionInfo {
 public:
-  explicit InlineFunctionInfo(CallGraph *cg = 0, const DataLayout *DL = 0)
+  explicit InlineFunctionInfo(CallGraph *cg = nullptr, const DataLayout *DL = nullptr)
     : CG(cg), DL(DL) {}
   
   /// CG - If non-null, InlineFunction will update the callgraph to reflect the
diff --git a/include/llvm/Transforms/Utils/ValueMapper.h b/include/llvm/Transforms/Utils/ValueMapper.h
index e96610e76af..33578bbcf22 100644
--- a/include/llvm/Transforms/Utils/ValueMapper.h
+++ b/include/llvm/Transforms/Utils/ValueMapper.h
@@ -68,27 +68,27 @@ namespace llvm {
   
   Value *MapValue(const Value *V, ValueToValueMapTy &VM,
                   RemapFlags Flags = RF_None,
-                  ValueMapTypeRemapper *TypeMapper = 0,
-                  ValueMaterializer *Materializer = 0);
+                  ValueMapTypeRemapper *TypeMapper = nullptr,
+                  ValueMaterializer *Materializer = nullptr);
 
   void RemapInstruction(Instruction *I, ValueToValueMapTy &VM,
                         RemapFlags Flags = RF_None,
-                        ValueMapTypeRemapper *TypeMapper = 0,
-                        ValueMaterializer *Materializer = 0);
+                        ValueMapTypeRemapper *TypeMapper = nullptr,
+                        ValueMaterializer *Materializer = nullptr);
   
   /// MapValue - provide versions that preserve type safety for MDNode and
   /// Constants.
   inline MDNode *MapValue(const MDNode *V, ValueToValueMapTy &VM,
                           RemapFlags Flags = RF_None,
-                          ValueMapTypeRemapper *TypeMapper = 0,
-                          ValueMaterializer *Materializer = 0) {
+                          ValueMapTypeRemapper *TypeMapper = nullptr,
+                          ValueMaterializer *Materializer = nullptr) {
     return cast<MDNode>(MapValue((const Value*)V, VM, Flags, TypeMapper,
                                  Materializer));
   }
   inline Constant *MapValue(const Constant *V, ValueToValueMapTy &VM,
                             RemapFlags Flags = RF_None,
-                            ValueMapTypeRemapper *TypeMapper = 0,
-                            ValueMaterializer *Materializer = 0) {
+                            ValueMapTypeRemapper *TypeMapper = nullptr,
+                            ValueMaterializer *Materializer = nullptr) {
     return cast<Constant>(MapValue((const Value*)V, VM, Flags, TypeMapper,
                                    Materializer));
   }
diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index c717a53f3a9..0e75b4612b7 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -150,7 +150,7 @@ static bool isLabelChar(char C) {
 static const char *isLabelTail(const char *CurPtr) {
   while (1) {
     if (CurPtr[0] == ':') return CurPtr+1;
-    if (!isLabelChar(CurPtr[0])) return 0;
+    if (!isLabelChar(CurPtr[0])) return nullptr;
     ++CurPtr;
   }
 }
@@ -435,8 +435,8 @@ lltok::Kind LLLexer::LexHash() {
 ///    HexIntConstant  [us]0x[0-9A-Fa-f]+
 lltok::Kind LLLexer::LexIdentifier() {
   const char *StartChar = CurPtr;
-  const char *IntEnd = CurPtr[-1] == 'i' ? 0 : StartChar;
-  const char *KeywordEnd = 0;
+  const char *IntEnd = CurPtr[-1] == 'i' ? nullptr : StartChar;
+  const char *KeywordEnd = nullptr;
 
   for (; isLabelChar(*CurPtr); ++CurPtr) {
     // If we decide this is an integer, remember the end of the sequence.
@@ -455,7 +455,7 @@ lltok::Kind LLLexer::LexIdentifier() {
 
   // Otherwise, this wasn't a label.  If this was valid as an integer type,
   // return it.
-  if (IntEnd == 0) IntEnd = CurPtr;
+  if (!IntEnd) IntEnd = CurPtr;
   if (IntEnd != StartChar) {
     CurPtr = IntEnd;
     uint64_t NumBits = atoull(StartChar, CurPtr);
@@ -469,7 +469,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   }
 
   // Otherwise, this was a letter sequence.  See which keyword this is.
-  if (KeywordEnd == 0) KeywordEnd = CurPtr;
+  if (!KeywordEnd) KeywordEnd = CurPtr;
   CurPtr = KeywordEnd;
   --StartChar;
   unsigned Len = CurPtr-StartChar;
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index b5c7f16ea2b..7e11aecd927 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -57,7 +57,8 @@ bool LLParser::ValidateEndOfModule() {
       for (unsigned i = 0, e = MDList.size(); i != e; ++i) {
         unsigned SlotNo = MDList[i].MDSlot;
 
-        if (SlotNo >= NumberedMetadata.size() || NumberedMetadata[SlotNo] == 0)
+        if (SlotNo >= NumberedMetadata.size() ||
+            NumberedMetadata[SlotNo] == nullptr)
           return Error(MDList[i].Loc, "use of undefined metadata '!" +
                        Twine(SlotNo) + "'");
         Inst->setMetadata(MDList[i].MDKind, NumberedMetadata[SlotNo]);
@@ -132,20 +133,20 @@ bool LLParser::ValidateEndOfModule() {
   // references after the function was defined.  Resolve those now.
   while (!ForwardRefBlockAddresses.empty()) {
     // Okay, we are referencing an already-parsed function, resolve them now.
-    Function *TheFn = 0;
+    Function *TheFn = nullptr;
     const ValID &Fn = ForwardRefBlockAddresses.begin()->first;
     if (Fn.Kind == ValID::t_GlobalName)
       TheFn = M->getFunction(Fn.StrVal);
     else if (Fn.UIntVal < NumberedVals.size())
       TheFn = dyn_cast<Function>(NumberedVals[Fn.UIntVal]);
 
-    if (TheFn == 0)
+    if (!TheFn)
       return Error(Fn.Loc, "unknown function referenced by blockaddress");
 
     // Resolve all these references.
     if (ResolveForwardRefBlockAddresses(TheFn,
                                       ForwardRefBlockAddresses.begin()->second,
-                                        0))
+                                        nullptr))
       return true;
 
     ForwardRefBlockAddresses.erase(ForwardRefBlockAddresses.begin());
@@ -206,7 +207,7 @@ bool LLParser::ResolveForwardRefBlockAddresses(Function *TheFn,
                      TheFn->getValueSymbolTable().lookup(Refs[i].first.StrVal));
     }
 
-    if (Res == 0)
+    if (!Res)
       return Error(Refs[i].first.Loc,
                    "referenced value is not a basic block");
 
@@ -364,7 +365,7 @@ bool LLParser::ParseUnnamedType() {
   if (TypeID >= NumberedTypes.size())
     NumberedTypes.resize(TypeID+1);
 
-  Type *Result = 0;
+  Type *Result = nullptr;
   if (ParseStructDefinition(TypeLoc, "",
                             NumberedTypes[TypeID], Result)) return true;
 
@@ -391,7 +392,7 @@ bool LLParser::ParseNamedType() {
       ParseToken(lltok::kw_type, "expected 'type' after name"))
     return true;
 
-  Type *Result = 0;
+  Type *Result = nullptr;
   if (ParseStructDefinition(NameLoc, Name,
                             NamedTypes[Name], Result)) return true;
 
@@ -523,10 +524,10 @@ bool LLParser::ParseMDNodeID(MDNode *&Result, unsigned &SlotNo) {
   if (ParseUInt32(SlotNo)) return true;
 
   // Check existing MDNode.
-  if (SlotNo < NumberedMetadata.size() && NumberedMetadata[SlotNo] != 0)
+  if (SlotNo < NumberedMetadata.size() && NumberedMetadata[SlotNo] != nullptr)
     Result = NumberedMetadata[SlotNo];
   else
-    Result = 0;
+    Result = nullptr;
   return false;
 }
 
@@ -567,7 +568,7 @@ bool LLParser::ParseNamedMetadata() {
       if (ParseToken(lltok::exclaim, "Expected '!' here"))
         return true;
 
-      MDNode *N = 0;
+      MDNode *N = nullptr;
       if (ParseMDNodeID(N)) return true;
       NMD->addOperand(N);
     } while (EatIfPresent(lltok::comma));
@@ -586,14 +587,14 @@ bool LLParser::ParseStandaloneMetadata() {
   unsigned MetadataID = 0;
 
   LocTy TyLoc;
-  Type *Ty = 0;
+  Type *Ty = nullptr;
   SmallVector<Value *, 16> Elts;
   if (ParseUInt32(MetadataID) ||
       ParseToken(lltok::equal, "expected '=' here") ||
       ParseType(Ty, TyLoc) ||
       ParseToken(lltok::exclaim, "Expected '!' here") ||
       ParseToken(lltok::lbrace, "Expected '{' here") ||
-      ParseMDNodeVector(Elts, NULL) ||
+      ParseMDNodeVector(Elts, nullptr) ||
       ParseToken(lltok::rbrace, "expected end of metadata node"))
     return true;
 
@@ -613,7 +614,7 @@ bool LLParser::ParseStandaloneMetadata() {
     if (MetadataID >= NumberedMetadata.size())
       NumberedMetadata.resize(MetadataID+1);
 
-    if (NumberedMetadata[MetadataID] != 0)
+    if (NumberedMetadata[MetadataID] != nullptr)
       return TokError("Metadata id is already used");
     NumberedMetadata[MetadataID] = Init;
   }
@@ -720,7 +721,7 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
   LocTy IsExternallyInitializedLoc;
   LocTy TyLoc;
 
-  Type *Ty = 0;
+  Type *Ty = nullptr;
   if (ParseOptionalThreadLocal(TLM) ||
       ParseOptionalAddrSpace(AddrSpace) ||
       ParseOptionalToken(lltok::kw_unnamed_addr, UnnamedAddr,
@@ -734,7 +735,7 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
 
   // If the linkage is specified and is external, then no initializer is
   // present.
-  Constant *Init = 0;
+  Constant *Init = nullptr;
   if (!HasLinkage || (Linkage != GlobalValue::ExternalWeakLinkage &&
                       Linkage != GlobalValue::ExternalLinkage)) {
     if (ParseGlobalValue(Ty, Init))
@@ -744,7 +745,7 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
   if (Ty->isFunctionTy() || Ty->isLabelTy())
     return Error(TyLoc, "invalid type for global variable");
 
-  GlobalVariable *GV = 0;
+  GlobalVariable *GV = nullptr;
 
   // See if the global was forward referenced, if so, use the global.
   if (!Name.empty()) {
@@ -762,9 +763,9 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
     }
   }
 
-  if (GV == 0) {
-    GV = new GlobalVariable(*M, Ty, false, GlobalValue::ExternalLinkage, 0,
-                            Name, 0, GlobalVariable::NotThreadLocal,
+  if (!GV) {
+    GV = new GlobalVariable(*M, Ty, false, GlobalValue::ExternalLinkage, nullptr,
+                            Name, nullptr, GlobalVariable::NotThreadLocal,
                             AddrSpace);
   } else {
     if (GV->getType()->getElementType() != Ty)
@@ -980,9 +981,9 @@ bool LLParser::ParseFnAttributeValuePairs(AttrBuilder &B,
 GlobalValue *LLParser::GetGlobalVal(const std::string &Name, Type *Ty,
                                     LocTy Loc) {
   PointerType *PTy = dyn_cast<PointerType>(Ty);
-  if (PTy == 0) {
+  if (!PTy) {
     Error(Loc, "global variable reference must have pointer type");
-    return 0;
+    return nullptr;
   }
 
   // Look this name up in the normal function symbol table.
@@ -991,7 +992,7 @@ GlobalValue *LLParser::GetGlobalVal(const std::string &Name, Type *Ty,
 
   // If this is a forward reference for the value, see if we already created a
   // forward ref record.
-  if (Val == 0) {
+  if (!Val) {
     std::map<std::string, std::pair<GlobalValue*, LocTy> >::iterator
       I = ForwardRefVals.find(Name);
     if (I != ForwardRefVals.end())
@@ -1003,7 +1004,7 @@ GlobalValue *LLParser::GetGlobalVal(const std::string &Name, Type *Ty,
     if (Val->getType() == Ty) return Val;
     Error(Loc, "'@" + Name + "' defined with type '" +
           getTypeString(Val->getType()) + "'");
-    return 0;
+    return nullptr;
   }
 
   // Otherwise, create a new forward reference for this value and remember it.
@@ -1012,8 +1013,8 @@ GlobalValue *LLParser::GetGlobalVal(const std::string &Name, Type *Ty,
     FwdVal = Function::Create(FT, GlobalValue::ExternalWeakLinkage, Name, M);
   else
     FwdVal = new GlobalVariable(*M, PTy->getElementType(), false,
-                                GlobalValue::ExternalWeakLinkage, 0, Name,
-                                0, GlobalVariable::NotThreadLocal,
+                                GlobalValue::ExternalWeakLinkage, nullptr, Name,
+                                nullptr, GlobalVariable::NotThreadLocal,
                                 PTy->getAddressSpace());
 
   ForwardRefVals[Name] = std::make_pair(FwdVal, Loc);
@@ -1022,16 +1023,16 @@ GlobalValue *LLParser::GetGlobalVal(const std::string &Name, Type *Ty,
 
 GlobalValue *LLParser::GetGlobalVal(unsigned ID, Type *Ty, LocTy Loc) {
   PointerType *PTy = dyn_cast<PointerType>(Ty);
-  if (PTy == 0) {
+  if (!PTy) {
     Error(Loc, "global variable reference must have pointer type");
-    return 0;
+    return nullptr;
   }
 
-  GlobalValue *Val = ID < NumberedVals.size() ? NumberedVals[ID] : 0;
+  GlobalValue *Val = ID < NumberedVals.size() ? NumberedVals[ID] : nullptr;
 
   // If this is a forward reference for the value, see if we already created a
   // forward ref record.
-  if (Val == 0) {
+  if (!Val) {
     std::map<unsigned, std::pair<GlobalValue*, LocTy> >::iterator
       I = ForwardRefValIDs.find(ID);
     if (I != ForwardRefValIDs.end())
@@ -1043,7 +1044,7 @@ GlobalValue *LLParser::GetGlobalVal(unsigned ID, Type *Ty, LocTy Loc) {
     if (Val->getType() == Ty) return Val;
     Error(Loc, "'@" + Twine(ID) + "' defined with type '" +
           getTypeString(Val->getType()) + "'");
-    return 0;
+    return nullptr;
   }
 
   // Otherwise, create a new forward reference for this value and remember it.
@@ -1052,7 +1053,7 @@ GlobalValue *LLParser::GetGlobalVal(unsigned ID, Type *Ty, LocTy Loc) {
     FwdVal = Function::Create(FT, GlobalValue::ExternalWeakLinkage, "", M);
   else
     FwdVal = new GlobalVariable(*M, PTy->getElementType(), false,
-                                GlobalValue::ExternalWeakLinkage, 0, "");
+                                GlobalValue::ExternalWeakLinkage, nullptr, "");
 
   ForwardRefValIDs[ID] = std::make_pair(FwdVal, Loc);
   return FwdVal;
@@ -1638,7 +1639,7 @@ bool LLParser::ParseType(Type *&Result, bool AllowVoid) {
 
     // If the type hasn't been defined yet, create a forward definition and
     // remember where that forward def'n was seen (in case it never is defined).
-    if (Entry.first == 0) {
+    if (!Entry.first) {
       Entry.first = StructType::create(Context, Lex.getStrVal());
       Entry.second = Lex.getLoc();
     }
@@ -1655,7 +1656,7 @@ bool LLParser::ParseType(Type *&Result, bool AllowVoid) {
 
     // If the type hasn't been defined yet, create a forward definition and
     // remember where that forward def'n was seen (in case it never is defined).
-    if (Entry.first == 0) {
+    if (!Entry.first) {
       Entry.first = StructType::create(Context);
       Entry.second = Lex.getLoc();
     }
@@ -1731,7 +1732,7 @@ bool LLParser::ParseParameterList(SmallVectorImpl<ParamInfo> &ArgList,
 
     // Parse the argument.
     LocTy ArgLoc;
-    Type *ArgTy = 0;
+    Type *ArgTy = nullptr;
     AttrBuilder ArgAttrs;
     Value *V;
     if (ParseType(ArgTy, ArgLoc))
@@ -1773,7 +1774,7 @@ bool LLParser::ParseArgumentList(SmallVectorImpl<ArgInfo> &ArgList,
     Lex.Lex();
   } else {
     LocTy TypeLoc = Lex.getLoc();
-    Type *ArgTy = 0;
+    Type *ArgTy = nullptr;
     AttrBuilder Attrs;
     std::string Name;
 
@@ -1885,7 +1886,7 @@ bool LLParser::ParseStructDefinition(SMLoc TypeLoc, StringRef Name,
     Entry.second = SMLoc();
 
     // If this type number has never been uttered, create it.
-    if (Entry.first == 0)
+    if (!Entry.first)
       Entry.first = StructType::create(Context, Name);
     ResultTy = Entry.first;
     return false;
@@ -1901,7 +1902,7 @@ bool LLParser::ParseStructDefinition(SMLoc TypeLoc, StringRef Name,
     if (Entry.first)
       return Error(TypeLoc, "forward references to non-struct type");
 
-    ResultTy = 0;
+    ResultTy = nullptr;
     if (isPacked)
       return ParseArrayVectorType(ResultTy, true);
     return ParseType(ResultTy);
@@ -1911,7 +1912,7 @@ bool LLParser::ParseStructDefinition(SMLoc TypeLoc, StringRef Name,
   Entry.second = SMLoc();
 
   // If this type number has never been uttered, create it.
-  if (Entry.first == 0)
+  if (!Entry.first)
     Entry.first = StructType::create(Context, Name);
 
   StructType *STy = cast<StructType>(Entry.first);
@@ -1942,7 +1943,7 @@ bool LLParser::ParseStructBody(SmallVectorImpl<Type*> &Body) {
     return false;
 
   LocTy EltTyLoc = Lex.getLoc();
-  Type *Ty = 0;
+  Type *Ty = nullptr;
   if (ParseType(Ty)) return true;
   Body.push_back(Ty);
 
@@ -1980,7 +1981,7 @@ bool LLParser::ParseArrayVectorType(Type *&Result, bool isVector) {
       return true;
 
   LocTy TypeLoc = Lex.getLoc();
-  Type *EltTy = 0;
+  Type *EltTy = nullptr;
   if (ParseType(EltTy)) return true;
 
   if (ParseToken(isVector ? lltok::greater : lltok::rsquare,
@@ -2026,7 +2027,7 @@ LLParser::PerFunctionState::~PerFunctionState() {
       I->second.first->replaceAllUsesWith(
                            UndefValue::get(I->second.first->getType()));
       delete I->second.first;
-      I->second.first = 0;
+      I->second.first = nullptr;
     }
 
   for (std::map<unsigned, std::pair<Value*, LocTy> >::iterator
@@ -2035,7 +2036,7 @@ LLParser::PerFunctionState::~PerFunctionState() {
       I->second.first->replaceAllUsesWith(
                            UndefValue::get(I->second.first->getType()));
       delete I->second.first;
-      I->second.first = 0;
+      I->second.first = nullptr;
     }
 }
 
@@ -2084,7 +2085,7 @@ Value *LLParser::PerFunctionState::GetVal(const std::string &Name,
 
   // If this is a forward reference for the value, see if we already created a
   // forward ref record.
-  if (Val == 0) {
+  if (!Val) {
     std::map<std::string, std::pair<Value*, LocTy> >::iterator
       I = ForwardRefVals.find(Name);
     if (I != ForwardRefVals.end())
@@ -2099,13 +2100,13 @@ Value *LLParser::PerFunctionState::GetVal(const std::string &Name,
     else
       P.Error(Loc, "'%" + Name + "' defined with type '" +
               getTypeString(Val->getType()) + "'");
-    return 0;
+    return nullptr;
   }
 
   // Don't make placeholders with invalid type.
   if (!Ty->isFirstClassType() && !Ty->isLabelTy()) {
     P.Error(Loc, "invalid use of a non-first-class type");
-    return 0;
+    return nullptr;
   }
 
   // Otherwise, create a new forward reference for this value and remember it.
@@ -2122,11 +2123,11 @@ Value *LLParser::PerFunctionState::GetVal(const std::string &Name,
 Value *LLParser::PerFunctionState::GetVal(unsigned ID, Type *Ty,
                                           LocTy Loc) {
   // Look this name up in the normal function symbol table.
-  Value *Val = ID < NumberedVals.size() ? NumberedVals[ID] : 0;
+  Value *Val = ID < NumberedVals.size() ? NumberedVals[ID] : nullptr;
 
   // If this is a forward reference for the value, see if we already created a
   // forward ref record.
-  if (Val == 0) {
+  if (!Val) {
     std::map<unsigned, std::pair<Value*, LocTy> >::iterator
       I = ForwardRefValIDs.find(ID);
     if (I != ForwardRefValIDs.end())
@@ -2141,12 +2142,12 @@ Value *LLParser::PerFunctionState::GetVal(unsigned ID, Type *Ty,
     else
       P.Error(Loc, "'%" + Twine(ID) + "' defined with type '" +
               getTypeString(Val->getType()) + "'");
-    return 0;
+    return nullptr;
   }
 
   if (!Ty->isFirstClassType() && !Ty->isLabelTy()) {
     P.Error(Loc, "invalid use of a non-first-class type");
-    return 0;
+    return nullptr;
   }
 
   // Otherwise, create a new forward reference for this value and remember it.
@@ -2242,7 +2243,7 @@ BasicBlock *LLParser::PerFunctionState::DefineBB(const std::string &Name,
     BB = GetBB(NumberedVals.size(), Loc);
   else
     BB = GetBB(Name, Loc);
-  if (BB == 0) return 0; // Already diagnosed error.
+  if (!BB) return nullptr; // Already diagnosed error.
 
   // Move the block to the end of the function.  Forward ref'd blocks are
   // inserted wherever they happen to be referenced.
@@ -2450,7 +2451,7 @@ bool LLParser::ParseValID(ValID &ID, PerFunctionState *PFS) {
     // Make a global variable as a placeholder for this reference.
     GlobalVariable *FwdRef = new GlobalVariable(*M, Type::getInt8Ty(Context),
                                            false, GlobalValue::InternalLinkage,
-                                                0, "");
+                                                nullptr, "");
     ForwardRefBlockAddresses[Fn].push_back(std::make_pair(Label, FwdRef));
     ID.ConstantVal = FwdRef;
     ID.Kind = ValID::t_Constant;
@@ -2471,7 +2472,7 @@ bool LLParser::ParseValID(ValID &ID, PerFunctionState *PFS) {
   case lltok::kw_inttoptr:
   case lltok::kw_ptrtoint: {
     unsigned Opc = Lex.getUIntVal();
-    Type *DestTy = 0;
+    Type *DestTy = nullptr;
     Constant *SrcVal;
     Lex.Lex();
     if (ParseToken(lltok::lparen, "expected '(' after constantexpr cast") ||
@@ -2735,18 +2736,18 @@ bool LLParser::ParseValID(ValID &ID, PerFunctionState *PFS) {
 
 /// ParseGlobalValue - Parse a global value with the specified type.
 bool LLParser::ParseGlobalValue(Type *Ty, Constant *&C) {
-  C = 0;
+  C = nullptr;
   ValID ID;
-  Value *V = NULL;
+  Value *V = nullptr;
   bool Parsed = ParseValID(ID) ||
-                ConvertValIDToValue(Ty, ID, V, NULL);
+                ConvertValIDToValue(Ty, ID, V, nullptr);
   if (V && !(C = dyn_cast<Constant>(V)))
     return Error(ID.Loc, "global values must be constants");
   return Parsed;
 }
 
 bool LLParser::ParseGlobalTypeAndValue(Constant *&V) {
-  Type *Ty = 0;
+  Type *Ty = nullptr;
   return ParseType(Ty) ||
          ParseGlobalValue(Ty, V);
 }
@@ -2830,15 +2831,15 @@ bool LLParser::ConvertValIDToValue(Type *Ty, ValID &ID, Value *&V,
   case ValID::t_LocalID:
     if (!PFS) return Error(ID.Loc, "invalid use of function-local name");
     V = PFS->GetVal(ID.UIntVal, Ty, ID.Loc);
-    return (V == 0);
+    return V == nullptr;
   case ValID::t_LocalName:
     if (!PFS) return Error(ID.Loc, "invalid use of function-local name");
     V = PFS->GetVal(ID.StrVal, Ty, ID.Loc);
-    return (V == 0);
+    return V == nullptr;
   case ValID::t_InlineAsm: {
     PointerType *PTy = dyn_cast<PointerType>(Ty);
     FunctionType *FTy =
-      PTy ? dyn_cast<FunctionType>(PTy->getElementType()) : 0;
+      PTy ? dyn_cast<FunctionType>(PTy->getElementType()) : nullptr;
     if (!FTy || !InlineAsm::Verify(FTy, ID.StrVal2))
       return Error(ID.Loc, "invalid type for inline asm constraint string");
     V = InlineAsm::get(FTy, ID.StrVal, ID.StrVal2, ID.UIntVal&1,
@@ -2857,10 +2858,10 @@ bool LLParser::ConvertValIDToValue(Type *Ty, ValID &ID, Value *&V,
     return false;
   case ValID::t_GlobalName:
     V = GetGlobalVal(ID.StrVal, Ty, ID.Loc);
-    return V == 0;
+    return V == nullptr;
   case ValID::t_GlobalID:
     V = GetGlobalVal(ID.UIntVal, Ty, ID.Loc);
-    return V == 0;
+    return V == nullptr;
   case ValID::t_APSInt:
     if (!Ty->isIntegerTy())
       return Error(ID.Loc, "integer constant must have integer type");
@@ -2943,14 +2944,14 @@ bool LLParser::ConvertValIDToValue(Type *Ty, ValID &ID, Value *&V,
 }
 
 bool LLParser::ParseValue(Type *Ty, Value *&V, PerFunctionState *PFS) {
-  V = 0;
+  V = nullptr;
   ValID ID;
   return ParseValID(ID, PFS) ||
          ConvertValIDToValue(Ty, ID, V, PFS);
 }
 
 bool LLParser::ParseTypeAndValue(Value *&V, PerFunctionState *PFS) {
-  Type *Ty = 0;
+  Type *Ty = nullptr;
   return ParseType(Ty) ||
          ParseValue(Ty, V, PFS);
 }
@@ -2980,7 +2981,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   unsigned DLLStorageClass;
   AttrBuilder RetAttrs;
   CallingConv::ID CC;
-  Type *RetType = 0;
+  Type *RetType = nullptr;
   LocTy RetTypeLoc = Lex.getLoc();
   if (ParseOptionalLinkage(Linkage) ||
       ParseOptionalVisibility(Visibility) ||
@@ -3046,7 +3047,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   std::string GC;
   bool UnnamedAddr;
   LocTy UnnamedAddrLoc;
-  Constant *Prefix = 0;
+  Constant *Prefix = nullptr;
 
   if (ParseArgumentList(ArgList, isVarArg) ||
       ParseOptionalToken(lltok::kw_unnamed_addr, UnnamedAddr,
@@ -3103,7 +3104,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
     FunctionType::get(RetType, ParamTypeList, isVarArg);
   PointerType *PFT = PointerType::getUnqual(FT);
 
-  Fn = 0;
+  Fn = nullptr;
   if (!FunctionName.empty()) {
     // If this was a definition of a forward reference, remove the definition
     // from the forward reference table and fill in the forward ref.
@@ -3141,7 +3142,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
     }
   }
 
-  if (Fn == 0)
+  if (!Fn)
     Fn = Function::Create(FT, GlobalValue::ExternalLinkage, FunctionName, M);
   else // Move the forward-reference to the correct spot in the module.
     M->getFunctionList().splice(M->end(), M->getFunctionList(), Fn);
@@ -3218,7 +3219,7 @@ bool LLParser::ParseBasicBlock(PerFunctionState &PFS) {
   }
 
   BasicBlock *BB = PFS.DefineBB(Name, NameLoc);
-  if (BB == 0) return true;
+  if (!BB) return true;
 
   std::string NameStr;
 
@@ -3432,7 +3433,7 @@ bool LLParser::ParseCmpPredicate(unsigned &P, unsigned Opc) {
 bool LLParser::ParseRet(Instruction *&Inst, BasicBlock *BB,
                         PerFunctionState &PFS) {
   SMLoc TypeLoc = Lex.getLoc();
-  Type *Ty = 0;
+  Type *Ty = nullptr;
   if (ParseType(Ty, true /*void allowed*/)) return true;
 
   Type *ResType = PFS.getFunction().getReturnType();
@@ -3582,7 +3583,7 @@ bool LLParser::ParseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy NoBuiltinLoc;
   CallingConv::ID CC;
-  Type *RetType = 0;
+  Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
   SmallVector<ParamInfo, 16> ArgList;
@@ -3604,8 +3605,8 @@ bool LLParser::ParseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
   // If RetType is a non-function pointer type, then this is the short syntax
   // for the call, which means that RetType is just the return type.  Infer the
   // rest of the function argument types from the arguments that are present.
-  PointerType *PFTy = 0;
-  FunctionType *Ty = 0;
+  PointerType *PFTy = nullptr;
+  FunctionType *Ty = nullptr;
   if (!(PFTy = dyn_cast<PointerType>(RetType)) ||
       !(Ty = dyn_cast<FunctionType>(PFTy->getElementType()))) {
     // Pull out the types of all of the arguments...
@@ -3638,7 +3639,7 @@ bool LLParser::ParseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
   FunctionType::param_iterator I = Ty->param_begin();
   FunctionType::param_iterator E = Ty->param_end();
   for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
-    Type *ExpectedTy = 0;
+    Type *ExpectedTy = nullptr;
     if (I != E) {
       ExpectedTy = *I++;
     } else if (!Ty->isVarArg()) {
@@ -3779,7 +3780,7 @@ bool LLParser::ParseCast(Instruction *&Inst, PerFunctionState &PFS,
                          unsigned Opc) {
   LocTy Loc;
   Value *Op;
-  Type *DestTy = 0;
+  Type *DestTy = nullptr;
   if (ParseTypeAndValue(Op, Loc, PFS) ||
       ParseToken(lltok::kw_to, "expected 'to' after cast value") ||
       ParseType(DestTy))
@@ -3818,7 +3819,7 @@ bool LLParser::ParseSelect(Instruction *&Inst, PerFunctionState &PFS) {
 ///   ::= 'va_arg' TypeAndValue ',' Type
 bool LLParser::ParseVA_Arg(Instruction *&Inst, PerFunctionState &PFS) {
   Value *Op;
-  Type *EltTy = 0;
+  Type *EltTy = nullptr;
   LocTy TypeLoc;
   if (ParseTypeAndValue(Op, PFS) ||
       ParseToken(lltok::comma, "expected ',' after vaarg operand") ||
@@ -3890,7 +3891,7 @@ bool LLParser::ParseShuffleVector(Instruction *&Inst, PerFunctionState &PFS) {
 /// ParsePHI
 ///   ::= 'phi' Type '[' Value ',' Value ']' (',' '[' Value ',' Value ']')*
 int LLParser::ParsePHI(Instruction *&Inst, PerFunctionState &PFS) {
-  Type *Ty = 0;  LocTy TypeLoc;
+  Type *Ty = nullptr;  LocTy TypeLoc;
   Value *Op0, *Op1;
 
   if (ParseType(Ty, TypeLoc) ||
@@ -3939,7 +3940,7 @@ int LLParser::ParsePHI(Instruction *&Inst, PerFunctionState &PFS) {
 ///   ::= 'filter'
 ///   ::= 'filter' TypeAndValue ( ',' TypeAndValue )*
 bool LLParser::ParseLandingPad(Instruction *&Inst, PerFunctionState &PFS) {
-  Type *Ty = 0; LocTy TyLoc;
+  Type *Ty = nullptr; LocTy TyLoc;
   Value *PersFn; LocTy PersFnLoc;
 
   if (ParseType(Ty, TyLoc) ||
@@ -3991,7 +3992,7 @@ bool LLParser::ParseCall(Instruction *&Inst, PerFunctionState &PFS,
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy BuiltinLoc;
   CallingConv::ID CC;
-  Type *RetType = 0;
+  Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
   SmallVector<ParamInfo, 16> ArgList;
@@ -4010,8 +4011,8 @@ bool LLParser::ParseCall(Instruction *&Inst, PerFunctionState &PFS,
   // If RetType is a non-function pointer type, then this is the short syntax
   // for the call, which means that RetType is just the return type.  Infer the
   // rest of the function argument types from the arguments that are present.
-  PointerType *PFTy = 0;
-  FunctionType *Ty = 0;
+  PointerType *PFTy = nullptr;
+  FunctionType *Ty = nullptr;
   if (!(PFTy = dyn_cast<PointerType>(RetType)) ||
       !(Ty = dyn_cast<FunctionType>(PFTy->getElementType()))) {
     // Pull out the types of all of the arguments...
@@ -4044,7 +4045,7 @@ bool LLParser::ParseCall(Instruction *&Inst, PerFunctionState &PFS,
   FunctionType::param_iterator I = Ty->param_begin();
   FunctionType::param_iterator E = Ty->param_end();
   for (unsigned i = 0, e = ArgList.size(); i != e; ++i) {
-    Type *ExpectedTy = 0;
+    Type *ExpectedTy = nullptr;
     if (I != E) {
       ExpectedTy = *I++;
     } else if (!Ty->isVarArg()) {
@@ -4088,10 +4089,10 @@ bool LLParser::ParseCall(Instruction *&Inst, PerFunctionState &PFS,
 /// ParseAlloc
 ///   ::= 'alloca' 'inalloca'? Type (',' TypeAndValue)? (',' 'align' i32)?
 int LLParser::ParseAlloc(Instruction *&Inst, PerFunctionState &PFS) {
-  Value *Size = 0;
+  Value *Size = nullptr;
   LocTy SizeLoc;
   unsigned Alignment = 0;
-  Type *Ty = 0;
+  Type *Ty = nullptr;
 
   bool IsInAlloca = EatIfPresent(lltok::kw_inalloca);
 
@@ -4330,8 +4331,8 @@ int LLParser::ParseFence(Instruction *&Inst, PerFunctionState &PFS) {
 /// ParseGetElementPtr
 ///   ::= 'getelementptr' 'inbounds'? TypeAndValue (',' TypeAndValue)*
 int LLParser::ParseGetElementPtr(Instruction *&Inst, PerFunctionState &PFS) {
-  Value *Ptr = 0;
-  Value *Val = 0;
+  Value *Ptr = nullptr;
+  Value *Val = nullptr;
   LocTy Loc, EltLoc;
 
   bool InBounds = EatIfPresent(lltok::kw_inbounds);
@@ -4433,11 +4434,11 @@ bool LLParser::ParseMDNodeVector(SmallVectorImpl<Value*> &Elts,
   do {
     // Null is a special case since it is typeless.
     if (EatIfPresent(lltok::kw_null)) {
-      Elts.push_back(0);
+      Elts.push_back(nullptr);
       continue;
     }
 
-    Value *V = 0;
+    Value *V = nullptr;
     if (ParseTypeAndValue(V, PFS)) return true;
     Elts.push_back(V);
   } while (EatIfPresent(lltok::comma));
diff --git a/lib/AsmParser/Parser.cpp b/lib/AsmParser/Parser.cpp
index a1da5e11639..2606bc2d083 100644
--- a/lib/AsmParser/Parser.cpp
+++ b/lib/AsmParser/Parser.cpp
@@ -30,12 +30,12 @@ Module *llvm::ParseAssembly(MemoryBuffer *F,
 
   // If we are parsing into an existing module, do it.
   if (M)
-    return LLParser(F, SM, Err, M).Run() ? 0 : M;
+    return LLParser(F, SM, Err, M).Run() ? nullptr : M;
 
   // Otherwise create a new module.
   std::unique_ptr<Module> M2(new Module(F->getBufferIdentifier(), Context));
   if (LLParser(F, SM, Err, M2.get()).Run())
-    return 0;
+    return nullptr;
   return M2.release();
 }
 
@@ -45,10 +45,10 @@ Module *llvm::ParseAssemblyFile(const std::string &Filename, SMDiagnostic &Err,
   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, File)) {
     Err = SMDiagnostic(Filename, SourceMgr::DK_Error,
                        "Could not open input file: " + ec.message());
-    return 0;
+    return nullptr;
   }
 
-  return ParseAssembly(File.release(), 0, Err, Context);
+  return ParseAssembly(File.release(), nullptr, Err, Context);
 }
 
 Module *llvm::ParseAssemblyString(const char *AsmString, Module *M,
diff --git a/lib/Bitcode/Reader/BitReader.cpp b/lib/Bitcode/Reader/BitReader.cpp
index 3e360a8b760..716299fc68e 100644
--- a/lib/Bitcode/Reader/BitReader.cpp
+++ b/lib/Bitcode/Reader/BitReader.cpp
@@ -35,7 +35,7 @@ LLVMBool LLVMParseBitcodeInContext(LLVMContextRef ContextRef,
   if (error_code EC = ModuleOrErr.getError()) {
     if (OutMessage)
       *OutMessage = strdup(EC.message().c_str());
-    *OutModule = wrap((Module*)0);
+    *OutModule = wrap((Module*)nullptr);
     return 1;
   }
 
@@ -55,7 +55,7 @@ LLVMBool LLVMGetBitcodeModuleInContext(LLVMContextRef ContextRef,
       getLazyBitcodeModule(unwrap(MemBuf), *unwrap(ContextRef));
 
   if (error_code EC = ModuleOrErr.getError()) {
-    *OutM = wrap((Module *)NULL);
+    *OutM = wrap((Module *)nullptr);
     if (OutMessage)
       *OutMessage = strdup(EC.message().c_str());
     return 1;
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index f712d9db641..178eaf082ef 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -41,7 +41,7 @@ void BitcodeReader::materializeForwardReferencedFunctions() {
 void BitcodeReader::FreeState() {
   if (BufferOwned)
     delete Buffer;
-  Buffer = 0;
+  Buffer = nullptr;
   std::vector<Type*>().swap(TypeList);
   ValueList.clear();
   MDValueList.clear();
@@ -258,7 +258,7 @@ void BitcodeReaderValueList::AssignValue(Value *V, unsigned Idx) {
     resize(Idx+1);
 
   WeakVH &OldV = ValuePtrs[Idx];
-  if (OldV == 0) {
+  if (!OldV) {
     OldV = V;
     return;
   }
@@ -298,12 +298,12 @@ Value *BitcodeReaderValueList::getValueFwdRef(unsigned Idx, Type *Ty) {
     resize(Idx + 1);
 
   if (Value *V = ValuePtrs[Idx]) {
-    assert((Ty == 0 || Ty == V->getType()) && "Type mismatch in value table!");
+    assert((!Ty || Ty == V->getType()) && "Type mismatch in value table!");
     return V;
   }
 
   // No type specified, must be invalid reference.
-  if (Ty == 0) return 0;
+  if (!Ty) return nullptr;
 
   // Create and return a placeholder, which will later be RAUW'd.
   Value *V = new Argument(Ty);
@@ -403,7 +403,7 @@ void BitcodeReaderMDValueList::AssignValue(Value *V, unsigned Idx) {
     resize(Idx+1);
 
   WeakVH &OldV = MDValuePtrs[Idx];
-  if (OldV == 0) {
+  if (!OldV) {
     OldV = V;
     return;
   }
@@ -435,7 +435,7 @@ Value *BitcodeReaderMDValueList::getValueFwdRef(unsigned Idx) {
 Type *BitcodeReader::getTypeByID(unsigned ID) {
   // The type table size is always specified correctly.
   if (ID >= TypeList.size())
-    return 0;
+    return nullptr;
 
   if (Type *Ty = TypeList[ID])
     return Ty;
@@ -737,7 +737,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
 
     // Read a record.
     Record.clear();
-    Type *ResultTy = 0;
+    Type *ResultTy = nullptr;
     switch (Stream.readRecord(Entry.ID, Record)) {
     default:
       return Error(InvalidValue);
@@ -792,7 +792,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
       if (Record.size() == 2)
         AddressSpace = Record[1];
       ResultTy = getTypeByID(Record[0]);
-      if (ResultTy == 0)
+      if (!ResultTy)
         return Error(InvalidType);
       ResultTy = PointerType::get(ResultTy, AddressSpace);
       break;
@@ -811,7 +811,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
       }
 
       ResultTy = getTypeByID(Record[2]);
-      if (ResultTy == 0 || ArgTys.size() < Record.size()-3)
+      if (!ResultTy || ArgTys.size() < Record.size()-3)
         return Error(InvalidType);
 
       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
@@ -830,7 +830,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
       }
 
       ResultTy = getTypeByID(Record[1]);
-      if (ResultTy == 0 || ArgTys.size() < Record.size()-2)
+      if (!ResultTy || ArgTys.size() < Record.size()-2)
         return Error(InvalidType);
 
       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
@@ -867,7 +867,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
       if (Res) {
         Res->setName(TypeName);
-        TypeList[NumRecords] = 0;
+        TypeList[NumRecords] = nullptr;
       } else  // Otherwise, create a new struct.
         Res = StructType::create(Context, TypeName);
       TypeName.clear();
@@ -896,7 +896,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
       if (Res) {
         Res->setName(TypeName);
-        TypeList[NumRecords] = 0;
+        TypeList[NumRecords] = nullptr;
       } else  // Otherwise, create a new struct with no body.
         Res = StructType::create(Context, TypeName);
       TypeName.clear();
@@ -924,7 +924,7 @@ error_code BitcodeReader::ParseTypeTableBody() {
     if (NumRecords >= TypeList.size())
       return Error(InvalidTYPETable);
     assert(ResultTy && "Didn't read a type?");
-    assert(TypeList[NumRecords] == 0 && "Already read type?");
+    assert(!TypeList[NumRecords] && "Already read type?");
     TypeList[NumRecords++] = ResultTy;
   }
 }
@@ -972,7 +972,7 @@ error_code BitcodeReader::ParseValueSymbolTable() {
       if (ConvertToString(Record, 1, ValueName))
         return Error(InvalidRecord);
       BasicBlock *BB = getBasicBlock(Record[0]);
-      if (BB == 0)
+      if (!BB)
         return Error(InvalidRecord);
 
       BB->setName(StringRef(ValueName.data(), ValueName.size()));
@@ -1028,7 +1028,7 @@ error_code BitcodeReader::ParseMetadata() {
       NamedMDNode *NMD = TheModule->getOrInsertNamedMetadata(Name);
       for (unsigned i = 0; i != Size; ++i) {
         MDNode *MD = dyn_cast_or_null<MDNode>(MDValueList.getValueFwdRef(Record[i]));
-        if (MD == 0)
+        if (!MD)
           return Error(InvalidRecord);
         NMD->addOperand(MD);
       }
@@ -1052,7 +1052,7 @@ error_code BitcodeReader::ParseMetadata() {
         else if (!Ty->isVoidTy())
           Elts.push_back(ValueList.getValueFwdRef(Record[i+1], Ty));
         else
-          Elts.push_back(NULL);
+          Elts.push_back(nullptr);
       }
       Value *V = MDNode::getWhenValsUnresolved(Context, Elts, IsFunctionLocal);
       IsFunctionLocal = false;
@@ -1185,7 +1185,7 @@ error_code BitcodeReader::ParseConstants() {
 
     // Read a record.
     Record.clear();
-    Value *V = 0;
+    Value *V = nullptr;
     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
     switch (BitCode) {
     default:  // Default behavior: unknown constant
@@ -1423,7 +1423,7 @@ error_code BitcodeReader::ParseConstants() {
         return Error(InvalidRecord);
       VectorType *OpTy =
         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
-      if (OpTy == 0)
+      if (!OpTy)
         return Error(InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2],
@@ -1433,7 +1433,7 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_INSERTELT: { // CE_INSERTELT: [opval, opval, opval]
       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
-      if (Record.size() < 3 || OpTy == 0)
+      if (Record.size() < 3 || !OpTy)
         return Error(InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
@@ -1445,7 +1445,7 @@ error_code BitcodeReader::ParseConstants() {
     }
     case bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
-      if (Record.size() < 3 || OpTy == 0)
+      if (Record.size() < 3 || !OpTy)
         return Error(InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
@@ -1459,7 +1459,7 @@ error_code BitcodeReader::ParseConstants() {
       VectorType *RTy = dyn_cast<VectorType>(CurTy);
       VectorType *OpTy =
         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
-      if (Record.size() < 4 || RTy == 0 || OpTy == 0)
+      if (Record.size() < 4 || !RTy || !OpTy)
         return Error(InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
@@ -1473,7 +1473,7 @@ error_code BitcodeReader::ParseConstants() {
       if (Record.size() < 4)
         return Error(InvalidRecord);
       Type *OpTy = getTypeByID(Record[0]);
-      if (OpTy == 0)
+      if (!OpTy)
         return Error(InvalidRecord);
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
@@ -1538,11 +1538,11 @@ error_code BitcodeReader::ParseConstants() {
       if (Record.size() < 3)
         return Error(InvalidRecord);
       Type *FnTy = getTypeByID(Record[0]);
-      if (FnTy == 0)
+      if (!FnTy)
         return Error(InvalidRecord);
       Function *Fn =
         dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
-      if (Fn == 0)
+      if (!Fn)
         return Error(InvalidRecord);
 
       // If the function is already parsed we can insert the block address right
@@ -1561,7 +1561,7 @@ error_code BitcodeReader::ParseConstants() {
         GlobalVariable *FwdRef = new GlobalVariable(*Fn->getParent(),
                                                     Type::getInt8Ty(Context),
                                             false, GlobalValue::InternalLinkage,
-                                                    0, "");
+                                                    nullptr, "");
         BlockAddrFwdRefs[Fn].push_back(std::make_pair(Record[2], FwdRef));
         V = FwdRef;
       }
@@ -1854,7 +1854,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
         ExternallyInitialized = Record[9];
 
       GlobalVariable *NewGV =
-        new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
+        new GlobalVariable(*TheModule, Ty, isConstant, Linkage, nullptr, "", nullptr,
                            TLM, AddressSpace, ExternallyInitialized);
       NewGV->setAlignment(Alignment);
       if (!Section.empty())
@@ -1944,7 +1944,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
         return Error(InvalidTypeForValue);
 
       GlobalAlias *NewGA = new GlobalAlias(Ty, GetDecodedLinkage(Record[2]),
-                                           "", 0, TheModule);
+                                           "", nullptr, TheModule);
       // Old bitcode files didn't have visibility field.
       if (Record.size() > 3)
         NewGA->setVisibility(GetDecodedVisibility(Record[3]));
@@ -1969,7 +1969,7 @@ error_code BitcodeReader::ParseModule(bool Resume) {
 }
 
 error_code BitcodeReader::ParseBitcodeInto(Module *M) {
-  TheModule = 0;
+  TheModule = nullptr;
 
   if (error_code EC = InitStream())
     return EC;
@@ -2173,7 +2173,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     ValueList.push_back(I);
 
   unsigned NextValueNo = ValueList.size();
-  BasicBlock *CurBB = 0;
+  BasicBlock *CurBB = nullptr;
   unsigned CurBBNo = 0;
 
   DebugLoc LastLoc;
@@ -2222,7 +2222,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
     // Read a record.
     Record.clear();
-    Instruction *I = 0;
+    Instruction *I = nullptr;
     unsigned BitCode = Stream.readRecord(Entry.ID, Record);
     switch (BitCode) {
     default: // Default behavior: reject
@@ -2240,7 +2240,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     case bitc::FUNC_CODE_DEBUG_LOC_AGAIN:  // DEBUG_LOC_AGAIN
       // This record indicates that the last instruction is at the same
       // location as the previous instruction with a location.
-      I = 0;
+      I = nullptr;
 
       // Get the last instruction emitted.
       if (CurBB && !CurBB->empty())
@@ -2249,31 +2249,31 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
                !FunctionBBs[CurBBNo-1]->empty())
         I = &FunctionBBs[CurBBNo-1]->back();
 
-      if (I == 0)
+      if (!I)
         return Error(InvalidRecord);
       I->setDebugLoc(LastLoc);
-      I = 0;
+      I = nullptr;
       continue;
 
     case bitc::FUNC_CODE_DEBUG_LOC: {      // DEBUG_LOC: [line, col, scope, ia]
-      I = 0;     // Get the last instruction emitted.
+      I = nullptr;     // Get the last instruction emitted.
       if (CurBB && !CurBB->empty())
         I = &CurBB->back();
       else if (CurBBNo && FunctionBBs[CurBBNo-1] &&
                !FunctionBBs[CurBBNo-1]->empty())
         I = &FunctionBBs[CurBBNo-1]->back();
-      if (I == 0 || Record.size() < 4)
+      if (!I || Record.size() < 4)
         return Error(InvalidRecord);
 
       unsigned Line = Record[0], Col = Record[1];
       unsigned ScopeID = Record[2], IAID = Record[3];
 
-      MDNode *Scope = 0, *IA = 0;
+      MDNode *Scope = nullptr, *IA = nullptr;
       if (ScopeID) Scope = cast<MDNode>(MDValueList.getValueFwdRef(ScopeID-1));
       if (IAID)    IA = cast<MDNode>(MDValueList.getValueFwdRef(IAID-1));
       LastLoc = DebugLoc::get(Line, Col, Scope, IA);
       I->setDebugLoc(LastLoc);
-      I = 0;
+      I = nullptr;
       continue;
     }
 
@@ -2333,9 +2333,9 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
       Type *ResTy = getTypeByID(Record[OpNum]);
       int Opc = GetDecodedCastOpcode(Record[OpNum+1]);
-      if (Opc == -1 || ResTy == 0)
+      if (Opc == -1 || !ResTy)
         return Error(InvalidRecord);
-      Instruction *Temp = 0;
+      Instruction *Temp = nullptr;
       if ((I = UpgradeBitCastInst(Opc, Op, ResTy, Temp))) {
         if (Temp) {
           InstructionList.push_back(Temp);
@@ -2526,7 +2526,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         }
 
         unsigned OpNum = 0;
-        Value *Op = NULL;
+        Value *Op = nullptr;
         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
           return Error(InvalidRecord);
         if (OpNum != Record.size())
@@ -2540,7 +2540,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       if (Record.size() != 1 && Record.size() != 3)
         return Error(InvalidRecord);
       BasicBlock *TrueDest = getBasicBlock(Record[0]);
-      if (TrueDest == 0)
+      if (!TrueDest)
         return Error(InvalidRecord);
 
       if (Record.size() == 1) {
@@ -2551,7 +2551,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         BasicBlock *FalseDest = getBasicBlock(Record[1]);
         Value *Cond = getValue(Record, 2, NextValueNo,
                                Type::getInt1Ty(Context));
-        if (FalseDest == 0 || Cond == 0)
+        if (!FalseDest || !Cond)
           return Error(InvalidRecord);
         I = BranchInst::Create(TrueDest, FalseDest, Cond);
         InstructionList.push_back(I);
@@ -2571,7 +2571,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
         Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
         BasicBlock *Default = getBasicBlock(Record[3]);
-        if (OpTy == 0 || Cond == 0 || Default == 0)
+        if (!OpTy || !Cond || !Default)
           return Error(InvalidRecord);
 
         unsigned NumCases = Record[4];
@@ -2628,7 +2628,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Type *OpTy = getTypeByID(Record[0]);
       Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
       BasicBlock *Default = getBasicBlock(Record[2]);
-      if (OpTy == 0 || Cond == 0 || Default == 0)
+      if (!OpTy || !Cond || !Default)
         return Error(InvalidRecord);
       unsigned NumCases = (Record.size()-3)/2;
       SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
@@ -2637,7 +2637,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         ConstantInt *CaseVal =
           dyn_cast_or_null<ConstantInt>(getFnValueByID(Record[3+i*2], OpTy));
         BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
-        if (CaseVal == 0 || DestBB == 0) {
+        if (!CaseVal || !DestBB) {
           delete SI;
           return Error(InvalidRecord);
         }
@@ -2651,7 +2651,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         return Error(InvalidRecord);
       Type *OpTy = getTypeByID(Record[0]);
       Value *Address = getValue(Record, 1, NextValueNo, OpTy);
-      if (OpTy == 0 || Address == 0)
+      if (!OpTy || !Address)
         return Error(InvalidRecord);
       unsigned NumDests = Record.size()-2;
       IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
@@ -2683,11 +2683,11 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         return Error(InvalidRecord);
 
       PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
-      FunctionType *FTy = !CalleeTy ? 0 :
+      FunctionType *FTy = !CalleeTy ? nullptr :
         dyn_cast<FunctionType>(CalleeTy->getElementType());
 
       // Check that the right number of fixed parameters are here.
-      if (FTy == 0 || NormalBB == 0 || UnwindBB == 0 ||
+      if (!FTy || !NormalBB || !UnwindBB ||
           Record.size() < OpNum+FTy->getNumParams())
         return Error(InvalidRecord);
 
@@ -2695,7 +2695,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
         Ops.push_back(getValue(Record, OpNum, NextValueNo,
                                FTy->getParamType(i)));
-        if (Ops.back() == 0)
+        if (!Ops.back())
           return Error(InvalidRecord);
       }
 
@@ -2721,7 +2721,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     }
     case bitc::FUNC_CODE_INST_RESUME: { // RESUME: [opval]
       unsigned Idx = 0;
-      Value *Val = 0;
+      Value *Val = nullptr;
       if (getValueTypePair(Record, Idx, NextValueNo, Val))
         return Error(InvalidRecord);
       I = ResumeInst::Create(Val);
@@ -2768,7 +2768,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
       Type *Ty = getTypeByID(Record[Idx++]);
       if (!Ty)
         return Error(InvalidRecord);
-      Value *PersFn = 0;
+      Value *PersFn = nullptr;
       if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
         return Error(InvalidRecord);
 
@@ -2961,7 +2961,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         return Error(InvalidRecord);
 
       PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
-      FunctionType *FTy = 0;
+      FunctionType *FTy = nullptr;
       if (OpTy) FTy = dyn_cast<FunctionType>(OpTy->getElementType());
       if (!FTy || Record.size() < FTy->getNumParams()+OpNum)
         return Error(InvalidRecord);
@@ -2974,7 +2974,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
         else
           Args.push_back(getValue(Record, OpNum, NextValueNo,
                                   FTy->getParamType(i)));
-        if (Args.back() == 0)
+        if (!Args.back())
           return Error(InvalidRecord);
       }
 
@@ -3015,7 +3015,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
 
     // Add instruction to end of current BB.  If there is no current BB, reject
     // this file.
-    if (CurBB == 0) {
+    if (!CurBB) {
       delete I;
       return Error(InvalidInstructionWithNoBB);
     }
@@ -3024,7 +3024,7 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
     // If this was a terminator instruction, move to the next block.
     if (isa<TerminatorInst>(I)) {
       ++CurBBNo;
-      CurBB = CurBBNo < FunctionBBs.size() ? FunctionBBs[CurBBNo] : 0;
+      CurBB = CurBBNo < FunctionBBs.size() ? FunctionBBs[CurBBNo] : nullptr;
     }
 
     // Non-void values get registered in the value table for future use.
@@ -3036,10 +3036,10 @@ OutOfRecordLoop:
 
   // Check the function list for unresolved values.
   if (Argument *A = dyn_cast<Argument>(ValueList.back())) {
-    if (A->getParent() == 0) {
+    if (!A->getParent()) {
       // We found at least one unresolved value.  Nuke them all to avoid leaks.
       for (unsigned i = ModuleValueListSize, e = ValueList.size(); i != e; ++i){
-        if ((A = dyn_cast_or_null<Argument>(ValueList[i])) && A->getParent() == 0) {
+        if ((A = dyn_cast_or_null<Argument>(ValueList[i])) && !A->getParent()) {
           A->replaceAllUsesWith(UndefValue::get(A->getType()));
           delete A;
         }
@@ -3348,7 +3348,7 @@ Module *llvm::getStreamedBitcodeModule(const std::string &name,
     if (ErrMsg)
       *ErrMsg = EC.message();
     delete M;  // Also deletes R.
-    return 0;
+    return nullptr;
   }
   R->setBufferOwned(false); // no buffer to delete
   return M;
diff --git a/lib/Bitcode/Reader/BitstreamReader.cpp b/lib/Bitcode/Reader/BitstreamReader.cpp
index 1fd9abd8b18..f31e1fa9b17 100644
--- a/lib/Bitcode/Reader/BitstreamReader.cpp
+++ b/lib/Bitcode/Reader/BitstreamReader.cpp
@@ -315,7 +315,7 @@ bool BitstreamCursor::ReadBlockInfoBlock() {
   if (EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID)) return true;
 
   SmallVector<uint64_t, 64> Record;
-  BitstreamReader::BlockInfo *CurBlockInfo = 0;
+  BitstreamReader::BlockInfo *CurBlockInfo = nullptr;
 
   // Read all the records for this module.
   while (1) {
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 5d1dac1e233..62dba414608 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -917,7 +917,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
   SmallVector<uint64_t, 64> Record;
 
   const ValueEnumerator::ValueList &Vals = VE.getValues();
-  Type *LastTy = 0;
+  Type *LastTy = nullptr;
   for (unsigned i = FirstVal; i != LastVal; ++i) {
     const Value *V = Vals[i].first;
     // If we need to switch types, do so now.
diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index a287cf9edb2..5b65d0ae1a6 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -290,7 +290,7 @@ DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
       cu->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
           cu, DW_AT_stmt_list, -1U);
   if (stmtOffset == -1U)
-    return 0; // No line table for this compile unit.
+    return nullptr; // No line table for this compile unit.
 
   // See if the line table is cached.
   if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
@@ -408,7 +408,7 @@ DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
   if (CU != CUs.end()) {
     return CU->get();
   }
-  return 0;
+  return nullptr;
 }
 
 DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
@@ -423,8 +423,7 @@ static bool getFileNameForCompileUnit(DWARFCompileUnit *CU,
                                       uint64_t FileIndex,
                                       bool NeedsAbsoluteFilePath,
                                       std::string &FileName) {
-  if (CU == 0 ||
-      LineTable == 0 ||
+  if (!CU || !LineTable ||
       !LineTable->getFileNameByIndex(FileIndex, NeedsAbsoluteFilePath,
                                      FileName))
     return false;
@@ -446,7 +445,7 @@ static bool getFileLineInfoForCompileUnit(DWARFCompileUnit *CU,
                                           bool NeedsAbsoluteFilePath,
                                           std::string &FileName,
                                           uint32_t &Line, uint32_t &Column) {
-  if (CU == 0 || LineTable == 0)
+  if (!CU || !LineTable)
     return false;
   // Get the index of row we're looking for in the line table.
   uint32_t RowIndex = LineTable->lookupAddress(Address);
@@ -560,7 +559,7 @@ DIInliningInfo DWARFContext::getInliningInfoForAddress(uint64_t Address,
 
   DIInliningInfo InliningInfo;
   uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
-  const DWARFLineTable *LineTable = 0;
+  const DWARFLineTable *LineTable = nullptr;
   for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
     const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
     std::string FileName = "<invalid>";
@@ -670,7 +669,7 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
             .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
             .Case("debug_addr", &AddrSection)
             // Any more debug info sections go here.
-            .Default(0);
+            .Default(nullptr);
     if (SectionData) {
       *SectionData = data;
       if (name == "debug_ranges") {
@@ -701,7 +700,7 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
         .Case("debug_loc", &LocSection.Relocs)
         .Case("debug_info.dwo", &InfoDWOSection.Relocs)
         .Case("debug_line", &LineSection.Relocs)
-        .Default(0);
+        .Default(nullptr);
     if (!Map) {
       // Find debug_types relocs by section rather than name as there are
       // multiple, comdat grouped, debug_types sections.
diff --git a/lib/DebugInfo/DWARFDebugAbbrev.cpp b/lib/DebugInfo/DWARFDebugAbbrev.cpp
index fd5f5e95fc1..6ff8eca956a 100644
--- a/lib/DebugInfo/DWARFDebugAbbrev.cpp
+++ b/lib/DebugInfo/DWARFDebugAbbrev.cpp
@@ -50,7 +50,7 @@ DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(uint32_t abbrCode)
     if (idx < Decls.size())
       return &Decls[idx];
   }
-  return NULL;
+  return nullptr;
 }
 
 DWARFDebugAbbrev::DWARFDebugAbbrev() :
@@ -99,5 +99,5 @@ DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t cu_abbr_offset) const {
 
   if (pos != AbbrevCollMap.end())
     return &(pos->second);
-  return NULL;
+  return nullptr;
 }
diff --git a/lib/DebugInfo/DWARFDebugFrame.cpp b/lib/DebugInfo/DWARFDebugFrame.cpp
index 5bf7b070b8e..425c47cbf03 100644
--- a/lib/DebugInfo/DWARFDebugFrame.cpp
+++ b/lib/DebugInfo/DWARFDebugFrame.cpp
@@ -251,7 +251,7 @@ public:
       int64_t LinkedCIEOffset, uint64_t InitialLocation, uint64_t AddressRange)
    : FrameEntry(FK_FDE, D, Offset, Length), LinkedCIEOffset(LinkedCIEOffset),
      InitialLocation(InitialLocation), AddressRange(AddressRange),
-     LinkedCIE(NULL) {}
+     LinkedCIE(nullptr) {}
 
   ~FDE() {
   }
@@ -334,7 +334,7 @@ void DWARFDebugFrame::parse(DataExtractor Data) {
     Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4);
     bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID);
 
-    FrameEntry *Entry = 0;
+    FrameEntry *Entry = nullptr;
     if (IsCIE) {
       // Note: this is specifically DWARFv3 CIE header structure. It was
       // changed in DWARFv4. We currently don't support reading DWARFv4
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.cpp b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
index bde25ec82d1..3acdc8f8c52 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.cpp
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
@@ -99,11 +99,11 @@ bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit *U,
   uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
   if (0 == AbbrCode) {
     // NULL debug tag entry.
-    AbbrevDecl = NULL;
+    AbbrevDecl = nullptr;
     return true;
   }
   AbbrevDecl = U->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
-  if (0 == AbbrevDecl) {
+  if (nullptr == AbbrevDecl) {
     // Restore the original offset.
     *OffsetPtr = Offset;
     return false;
@@ -266,14 +266,15 @@ bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
 const char *
 DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U) const {
   if (!isSubroutineDIE())
-    return 0;
+    return nullptr;
   // Try to get mangled name if possible.
   if (const char *name =
-      getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, 0))
+      getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
     return name;
-  if (const char *name = getAttributeValueAsString(U, DW_AT_linkage_name, 0))
+  if (const char *name = getAttributeValueAsString(U, DW_AT_linkage_name,
+                                                   nullptr))
     return name;
-  if (const char *name = getAttributeValueAsString(U, DW_AT_name, 0))
+  if (const char *name = getAttributeValueAsString(U, DW_AT_name, nullptr))
     return name;
   // Try to get name from specification DIE.
   uint32_t spec_ref =
@@ -295,7 +296,7 @@ DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U) const {
         return name;
     }
   }
-  return 0;
+  return nullptr;
 }
 
 void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFUnit *U,
diff --git a/lib/DebugInfo/DWARFDebugLine.cpp b/lib/DebugInfo/DWARFDebugLine.cpp
index 43d976480c7..de543eec2df 100644
--- a/lib/DebugInfo/DWARFDebugLine.cpp
+++ b/lib/DebugInfo/DWARFDebugLine.cpp
@@ -147,7 +147,7 @@ DWARFDebugLine::getLineTable(uint32_t offset) const {
   LineTableConstIter pos = LineTableMap.find(offset);
   if (pos != LineTableMap.end())
     return &pos->second;
-  return 0;
+  return nullptr;
 }
 
 const DWARFDebugLine::LineTable *
@@ -159,7 +159,7 @@ DWARFDebugLine::getOrParseLineTable(DataExtractor debug_line_data,
     // Parse and cache the line table for at this offset.
     State state;
     if (!parseStatementTable(debug_line_data, RelocMap, &offset, state))
-      return 0;
+      return nullptr;
     pos.first->second = state;
   }
   return &pos.first->second;
diff --git a/lib/DebugInfo/DWARFFormValue.cpp b/lib/DebugInfo/DWARFFormValue.cpp
index da71fb3d116..8d0f96620a4 100644
--- a/lib/DebugInfo/DWARFFormValue.cpp
+++ b/lib/DebugInfo/DWARFFormValue.cpp
@@ -131,7 +131,7 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
                                   const DWARFUnit *cu) {
   bool indirect = false;
   bool is_block = false;
-  Value.data = NULL;
+  Value.data = nullptr;
   // Read the value for the form into value and follow and DW_FORM_indirect
   // instances we run into
   do {
@@ -241,7 +241,7 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
 
   if (is_block) {
     StringRef str = data.getData().substr(*offset_ptr, Value.uval);
-    Value.data = NULL;
+    Value.data = nullptr;
     if (!str.empty()) {
       Value.data = reinterpret_cast<const uint8_t *>(str.data());
       *offset_ptr += Value.uval;
@@ -488,7 +488,7 @@ Optional<const char *> DWARFFormValue::getAsCString(const DWARFUnit *U) const {
     return None;
   if (Form == DW_FORM_string)
     return Value.cstr;
-  if (U == 0)
+  if (!U)
     return None;
   uint32_t Offset = Value.uval;
   if (Form == DW_FORM_GNU_str_index) {
@@ -509,7 +509,7 @@ Optional<uint64_t> DWARFFormValue::getAsAddress(const DWARFUnit *U) const {
   if (Form == DW_FORM_GNU_addr_index) {
     uint32_t Index = Value.uval;
     uint64_t Result;
-    if (U == 0 || !U->getAddrOffsetSectionItem(Index, Result))
+    if (!U || !U->getAddrOffsetSectionItem(Index, Result))
       return None;
     return Result;
   }
@@ -525,7 +525,7 @@ Optional<uint64_t> DWARFFormValue::getAsReference(const DWARFUnit *U) const {
   case DW_FORM_ref4:
   case DW_FORM_ref8:
   case DW_FORM_ref_udata:
-    if (U == 0)
+    if (!U)
       return None;
     return Value.uval + U->getOffset();
   case DW_FORM_ref_addr:
diff --git a/lib/DebugInfo/DWARFUnit.cpp b/lib/DebugInfo/DWARFUnit.cpp
index 316c208479a..afed8df484f 100644
--- a/lib/DebugInfo/DWARFUnit.cpp
+++ b/lib/DebugInfo/DWARFUnit.cpp
@@ -98,7 +98,7 @@ void DWARFUnit::clear() {
   Offset = 0;
   Length = 0;
   Version = 0;
-  Abbrevs = 0;
+  Abbrevs = nullptr;
   AddrSize = 0;
   BaseAddr = 0;
   RangeSectionBase = 0;
@@ -110,8 +110,8 @@ void DWARFUnit::clear() {
 const char *DWARFUnit::getCompilationDir() {
   extractDIEsIfNeeded(true);
   if (DieArray.empty())
-    return 0;
-  return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
+    return nullptr;
+  return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
 }
 
 uint64_t DWARFUnit::getDWOId() {
@@ -241,25 +241,25 @@ size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
 DWARFUnit::DWOHolder::DWOHolder(object::ObjectFile *DWOFile)
     : DWOFile(DWOFile),
       DWOContext(cast<DWARFContext>(DIContext::getDWARFContext(DWOFile))),
-      DWOU(0) {
+      DWOU(nullptr) {
   if (DWOContext->getNumDWOCompileUnits() > 0)
     DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
 }
 
 bool DWARFUnit::parseDWO() {
-  if (DWO.get() != 0)
+  if (DWO.get())
     return false;
   extractDIEsIfNeeded(true);
   if (DieArray.empty())
     return false;
   const char *DWOFileName =
-      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, 0);
-  if (DWOFileName == 0)
+      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, nullptr);
+  if (!DWOFileName)
     return false;
   const char *CompilationDir =
-      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
+      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
   SmallString<16> AbsolutePath;
-  if (sys::path::is_relative(DWOFileName) && CompilationDir != 0) {
+  if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
     sys::path::append(AbsolutePath, CompilationDir);
   }
   sys::path::append(AbsolutePath, DWOFileName);
@@ -271,7 +271,7 @@ bool DWARFUnit::parseDWO() {
   DWO.reset(new DWOHolder(DWOFile.get()));
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.
-  if (DWOCU == 0 || DWOCU->getDWOId() != getDWOId()) {
+  if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
     DWO.reset();
     return false;
   }
@@ -337,14 +337,14 @@ DWARFUnit::getSubprogramForAddress(uint64_t Address) {
       return &DIE;
     }
   }
-  return 0;
+  return nullptr;
 }
 
 DWARFDebugInfoEntryInlinedChain
 DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
   // First, find a subprogram that contains the given address (the root
   // of inlined chain).
-  const DWARFUnit *ChainCU = 0;
+  const DWARFUnit *ChainCU = nullptr;
   const DWARFDebugInfoEntryMinimal *SubprogramDIE =
       getSubprogramForAddress(Address);
   if (SubprogramDIE) {
diff --git a/lib/ExecutionEngine/ExecutionEngine.cpp b/lib/ExecutionEngine/ExecutionEngine.cpp
index 4768e67a1e9..4685d6d13b1 100644
--- a/lib/ExecutionEngine/ExecutionEngine.cpp
+++ b/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -50,19 +50,19 @@ ExecutionEngine *(*ExecutionEngine::JITCtor)(
   std::string *ErrorStr,
   JITMemoryManager *JMM,
   bool GVsWithCode,
-  TargetMachine *TM) = 0;
+  TargetMachine *TM) = nullptr;
 ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
   Module *M,
   std::string *ErrorStr,
   RTDyldMemoryManager *MCJMM,
   bool GVsWithCode,
-  TargetMachine *TM) = 0;
+  TargetMachine *TM) = nullptr;
 ExecutionEngine *(*ExecutionEngine::InterpCtor)(Module *M,
-                                                std::string *ErrorStr) = 0;
+                                                std::string *ErrorStr) =nullptr;
 
 ExecutionEngine::ExecutionEngine(Module *M)
   : EEState(*this),
-    LazyFunctionCreator(0) {
+    LazyFunctionCreator(nullptr) {
   CompilingLazily         = false;
   GVCompilationDisabled   = false;
   SymbolSearchingDisabled = false;
@@ -129,7 +129,7 @@ Function *ExecutionEngine::FindFunctionNamed(const char *FnName) {
     if (Function *F = Modules[i]->getFunction(FnName))
       return F;
   }
-  return 0;
+  return nullptr;
 }
 
 
@@ -141,7 +141,7 @@ void *ExecutionEngineState::RemoveMapping(const MutexGuard &,
   // FIXME: This is silly, we shouldn't end up with a mapping -> 0 in the
   // GlobalAddressMap.
   if (I == GlobalAddressMap.end())
-    OldVal = 0;
+    OldVal = nullptr;
   else {
     OldVal = I->second;
     GlobalAddressMap.erase(I);
@@ -157,14 +157,14 @@ void ExecutionEngine::addGlobalMapping(const GlobalValue *GV, void *Addr) {
   DEBUG(dbgs() << "JIT: Map \'" << GV->getName()
         << "\' to [" << Addr << "]\n";);
   void *&CurVal = EEState.getGlobalAddressMap(locked)[GV];
-  assert((CurVal == 0 || Addr == 0) && "GlobalMapping already established!");
+  assert((!CurVal || !Addr) && "GlobalMapping already established!");
   CurVal = Addr;
 
   // If we are using the reverse mapping, add it too.
   if (!EEState.getGlobalAddressReverseMap(locked).empty()) {
     AssertingVH<const GlobalValue> &V =
       EEState.getGlobalAddressReverseMap(locked)[Addr];
-    assert((V == 0 || GV == 0) && "GlobalMapping already established!");
+    assert((!V || !GV) && "GlobalMapping already established!");
     V = GV;
   }
 }
@@ -193,7 +193,7 @@ void *ExecutionEngine::updateGlobalMapping(const GlobalValue *GV, void *Addr) {
     EEState.getGlobalAddressMap(locked);
 
   // Deleting from the mapping?
-  if (Addr == 0)
+  if (!Addr)
     return EEState.RemoveMapping(locked, GV);
 
   void *&CurVal = Map[GV];
@@ -207,7 +207,7 @@ void *ExecutionEngine::updateGlobalMapping(const GlobalValue *GV, void *Addr) {
   if (!EEState.getGlobalAddressReverseMap(locked).empty()) {
     AssertingVH<const GlobalValue> &V =
       EEState.getGlobalAddressReverseMap(locked)[Addr];
-    assert((V == 0 || GV == 0) && "GlobalMapping already established!");
+    assert((!V || !GV) && "GlobalMapping already established!");
     V = GV;
   }
   return OldVal;
@@ -218,7 +218,7 @@ void *ExecutionEngine::getPointerToGlobalIfAvailable(const GlobalValue *GV) {
 
   ExecutionEngineState::GlobalAddressMapTy::iterator I =
     EEState.getGlobalAddressMap(locked).find(GV);
-  return I != EEState.getGlobalAddressMap(locked).end() ? I->second : 0;
+  return I != EEState.getGlobalAddressMap(locked).end() ? I->second : nullptr;
 }
 
 const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
@@ -235,7 +235,7 @@ const GlobalValue *ExecutionEngine::getGlobalValueAtAddress(void *Addr) {
 
   std::map<void *, AssertingVH<const GlobalValue> >::iterator I =
     EEState.getGlobalAddressReverseMap(locked).find(Addr);
-  return I != EEState.getGlobalAddressReverseMap(locked).end() ? I->second : 0;
+  return I != EEState.getGlobalAddressReverseMap(locked).end() ? I->second : nullptr;
 }
 
 namespace {
@@ -243,11 +243,11 @@ class ArgvArray {
   char *Array;
   std::vector<char*> Values;
 public:
-  ArgvArray() : Array(NULL) {}
+  ArgvArray() : Array(nullptr) {}
   ~ArgvArray() { clear(); }
   void clear() {
     delete[] Array;
-    Array = NULL;
+    Array = nullptr;
     for (size_t I = 0, E = Values.size(); I != E; ++I) {
       delete[] Values[I];
     }
@@ -283,7 +283,7 @@ void *ArgvArray::reset(LLVMContext &C, ExecutionEngine *EE,
   }
 
   // Null terminate it
-  EE->StoreValueToMemory(PTOGV(0),
+  EE->StoreValueToMemory(PTOGV(nullptr),
                          (GenericValue*)(Array+InputArgv.size()*PtrSize),
                          SBytePtr);
   return Array;
@@ -303,11 +303,11 @@ void ExecutionEngine::runStaticConstructorsDestructors(Module *module,
   // Should be an array of '{ i32, void ()* }' structs.  The first value is
   // the init priority, which we ignore.
   ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
-  if (InitList == 0)
+  if (!InitList)
     return;
   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
     ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i));
-    if (CS == 0) continue;
+    if (!CS) continue;
 
     Constant *FP = CS->getOperand(1);
     if (FP->isNullValue())
@@ -418,10 +418,10 @@ ExecutionEngine *ExecutionEngine::createJIT(Module *M,
                                             bool GVsWithCode,
                                             Reloc::Model RM,
                                             CodeModel::Model CMM) {
-  if (ExecutionEngine::JITCtor == 0) {
+  if (!ExecutionEngine::JITCtor) {
     if (ErrorStr)
       *ErrorStr = "JIT has not been linked in.";
-    return 0;
+    return nullptr;
   }
 
   // Use the defaults for extra parameters.  Users can use EngineBuilder to
@@ -437,7 +437,7 @@ ExecutionEngine *ExecutionEngine::createJIT(Module *M,
 
   // TODO: permit custom TargetOptions here
   TargetMachine *TM = EB.selectTarget();
-  if (!TM || (ErrorStr && ErrorStr->length() > 0)) return 0;
+  if (!TM || (ErrorStr && ErrorStr->length() > 0)) return nullptr;
 
   return ExecutionEngine::JITCtor(M, ErrorStr, JMM, GVsWithCode, TM);
 }
@@ -447,8 +447,8 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
 
   // Make sure we can resolve symbols in the program as well. The zero arg
   // to the function tells DynamicLibrary to load the program, not a library.
-  if (sys::DynamicLibrary::LoadLibraryPermanently(0, ErrorStr))
-    return 0;
+  if (sys::DynamicLibrary::LoadLibraryPermanently(nullptr, ErrorStr))
+    return nullptr;
 
   assert(!(JMM && MCJMM));
   
@@ -461,7 +461,7 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
     else {
       if (ErrorStr)
         *ErrorStr = "Cannot create an interpreter with a memory manager.";
-      return 0;
+      return nullptr;
     }
   }
   
@@ -470,7 +470,7 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
       *ErrorStr =
         "Cannot create a legacy JIT with a runtime dyld memory "
         "manager.";
-    return 0;
+    return nullptr;
   }
 
   // Unless the interpreter was explicitly selected or the JIT is not linked,
@@ -503,16 +503,16 @@ ExecutionEngine *EngineBuilder::create(TargetMachine *TM) {
       return ExecutionEngine::InterpCtor(M, ErrorStr);
     if (ErrorStr)
       *ErrorStr = "Interpreter has not been linked in.";
-    return 0;
+    return nullptr;
   }
 
-  if ((WhichEngine & EngineKind::JIT) && ExecutionEngine::JITCtor == 0 &&
-      ExecutionEngine::MCJITCtor == 0) {
+  if ((WhichEngine & EngineKind::JIT) && !ExecutionEngine::JITCtor &&
+      !ExecutionEngine::MCJITCtor) {
     if (ErrorStr)
       *ErrorStr = "JIT has not been linked in.";
   }
 
-  return 0;
+  return nullptr;
 }
 
 void *ExecutionEngine::getPointerToGlobal(const GlobalValue *GV) {
@@ -848,7 +848,7 @@ GenericValue ExecutionEngine::getConstantValue(const Constant *C) {
     break;
   case Type::PointerTyID:
     if (isa<ConstantPointerNull>(C))
-      Result.PointerVal = 0;
+      Result.PointerVal = nullptr;
     else if (const Function *F = dyn_cast<Function>(C))
       Result = PTOGV(getPointerToFunctionOrStub(const_cast<Function*>(F)));
     else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
@@ -1290,12 +1290,12 @@ void ExecutionEngine::emitGlobals() {
 void ExecutionEngine::EmitGlobalVariable(const GlobalVariable *GV) {
   void *GA = getPointerToGlobalIfAvailable(GV);
 
-  if (GA == 0) {
+  if (!GA) {
     // If it's not already specified, allocate memory for the global.
     GA = getMemoryForGV(GV);
 
     // If we failed to allocate memory for this global, return.
-    if (GA == 0) return;
+    if (!GA) return;
 
     addGlobalMapping(GV, GA);
   }
diff --git a/lib/ExecutionEngine/ExecutionEngineBindings.cpp b/lib/ExecutionEngine/ExecutionEngineBindings.cpp
index db3dead05a5..de707a09d5e 100644
--- a/lib/ExecutionEngine/ExecutionEngineBindings.cpp
+++ b/lib/ExecutionEngine/ExecutionEngineBindings.cpp
@@ -410,7 +410,7 @@ uint8_t *SimpleBindingMemoryManager::allocateDataSection(
 }
 
 bool SimpleBindingMemoryManager::finalizeMemory(std::string *ErrMsg) {
-  char *errMsgCString = 0;
+  char *errMsgCString = nullptr;
   bool result = Functions.FinalizeMemory(Opaque, &errMsgCString);
   assert((result || !errMsgCString) &&
          "Did not expect an error message if FinalizeMemory succeeded");
@@ -433,7 +433,7 @@ LLVMMCJITMemoryManagerRef LLVMCreateSimpleMCJITMemoryManager(
   
   if (!AllocateCodeSection || !AllocateDataSection || !FinalizeMemory ||
       !Destroy)
-    return NULL;
+    return nullptr;
   
   SimpleBindingMMFunctions functions;
   functions.AllocateCodeSection = AllocateCodeSection;
diff --git a/lib/ExecutionEngine/TargetSelect.cpp b/lib/ExecutionEngine/TargetSelect.cpp
index 9b7d3489790..b10d51f6486 100644
--- a/lib/ExecutionEngine/TargetSelect.cpp
+++ b/lib/ExecutionEngine/TargetSelect.cpp
@@ -47,7 +47,7 @@ TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
     TheTriple.setTriple(sys::getProcessTriple());
 
   // Adjust the triple to match what the user requested.
-  const Target *TheTarget = 0;
+  const Target *TheTarget = nullptr;
   if (!MArch.empty()) {
     for (TargetRegistry::iterator it = TargetRegistry::begin(),
            ie = TargetRegistry::end(); it != ie; ++it) {
@@ -61,7 +61,7 @@ TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
       if (ErrorStr)
         *ErrorStr = "No available targets are compatible with this -march, "
                     "see -version for the available targets.\n";
-      return 0;
+      return nullptr;
     }
 
     // Adjust the triple to match (if known), otherwise stick with the
@@ -72,10 +72,10 @@ TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
   } else {
     std::string Error;
     TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
-    if (TheTarget == 0) {
+    if (!TheTarget) {
       if (ErrorStr)
         *ErrorStr = Error;
-      return 0;
+      return nullptr;
     }
   }
 
diff --git a/lib/IR/BasicBlock.cpp b/lib/IR/BasicBlock.cpp
index 94d7deb37e3..ba07433103b 100644
--- a/lib/IR/BasicBlock.cpp
+++ b/lib/IR/BasicBlock.cpp
@@ -81,7 +81,7 @@ BasicBlock::~BasicBlock() {
     }
   }
 
-  assert(getParent() == 0 && "BasicBlock still linked into the program!");
+  assert(getParent() == nullptr && "BasicBlock still linked into the program!");
   dropAllReferences();
   InstList.clear();
 }
diff --git a/lib/IR/ConstantFold.cpp b/lib/IR/ConstantFold.cpp
index 1f0a25ba393..706e66fb422 100644
--- a/lib/IR/ConstantFold.cpp
+++ b/lib/IR/ConstantFold.cpp
@@ -1951,7 +1951,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
   if (isa<UndefValue>(C)) {
     PointerType *Ptr = cast<PointerType>(C->getType());
     Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
-    assert(Ty != 0 && "Invalid indices for GEP!");
+    assert(Ty && "Invalid indices for GEP!");
     return UndefValue::get(PointerType::get(Ty, Ptr->getAddressSpace()));
   }
 
@@ -1965,7 +1965,7 @@ static Constant *ConstantFoldGetElementPtrImpl(Constant *C,
     if (isNull) {
       PointerType *Ptr = cast<PointerType>(C->getType());
       Type *Ty = GetElementPtrInst::getIndexedType(Ptr, Idxs);
-      assert(Ty != 0 && "Invalid indices for GEP!");
+      assert(Ty && "Invalid indices for GEP!");
       return ConstantPointerNull::get(PointerType::get(Ty,
                                                        Ptr->getAddressSpace()));
     }
diff --git a/lib/IR/Constants.cpp b/lib/IR/Constants.cpp
index c28d16af383..8072bbcedcf 100644
--- a/lib/IR/Constants.cpp
+++ b/lib/IR/Constants.cpp
@@ -1354,7 +1354,7 @@ void UndefValue::destroyConstant() {
 //
 
 BlockAddress *BlockAddress::get(BasicBlock *BB) {
-  assert(BB->getParent() != 0 && "Block must have a parent");
+  assert(BB->getParent() && "Block must have a parent");
   return get(BB->getParent(), BB);
 }
 
@@ -1381,7 +1381,7 @@ BlockAddress *BlockAddress::lookup(const BasicBlock *BB) {
     return nullptr;
 
   const Function *F = BB->getParent();
-  assert(F != 0 && "Block must have a parent");
+  assert(F && "Block must have a parent");
   BlockAddress *BA =
       F->getContext().pImpl->BlockAddresses.lookup(std::make_pair(F, BB));
   assert(BA && "Refcount and block address map disagree!");
diff --git a/lib/IR/DebugLoc.cpp b/lib/IR/DebugLoc.cpp
index a45b622a71b..77faa7cc66b 100644
--- a/lib/IR/DebugLoc.cpp
+++ b/lib/IR/DebugLoc.cpp
@@ -260,7 +260,7 @@ void DebugRecVH::deleted() {
   
   MDNode *OldScope = Entry.first.get();
   MDNode *OldInlinedAt = Entry.second.get();
-  assert(OldScope != 0 && OldInlinedAt != 0 &&
+  assert(OldScope && OldInlinedAt &&
          "Entry should be non-canonical if either val dropped to null");
 
   // Otherwise, we do have an entry in it, nuke it and we're done.
@@ -314,7 +314,7 @@ void DebugRecVH::allUsesReplacedWith(Value *NewVa) {
   
   MDNode *OldScope = Entry.first.get();
   MDNode *OldInlinedAt = Entry.second.get();
-  assert(OldScope != 0 && OldInlinedAt != 0 &&
+  assert(OldScope && OldInlinedAt &&
          "Entry should be non-canonical if either val dropped to null");
   
   // Otherwise, we do have an entry in it, nuke it and we're done.
diff --git a/lib/IR/Instruction.cpp b/lib/IR/Instruction.cpp
index d2c47e7503a..e638540b2c9 100644
--- a/lib/IR/Instruction.cpp
+++ b/lib/IR/Instruction.cpp
@@ -53,7 +53,7 @@ Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
 
 // Out of line virtual method, so the vtable, etc has a home.
 Instruction::~Instruction() {
-  assert(Parent == 0 && "Instruction still linked in the program!");
+  assert(!Parent && "Instruction still linked in the program!");
   if (hasMetadataHashEntry())
     clearMetadataHashEntries();
 }
diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 7d4761487ff..5b93c5323ab 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -732,7 +732,7 @@ BranchInst::BranchInst(BasicBlock *IfTrue, Instruction *InsertBefore)
   : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                    OperandTraits<BranchInst>::op_end(this) - 1,
                    1, InsertBefore) {
-  assert(IfTrue != 0 && "Branch destination may not be null!");
+  assert(IfTrue && "Branch destination may not be null!");
   Op<-1>() = IfTrue;
 }
 BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *IfFalse, Value *Cond,
@@ -752,7 +752,7 @@ BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *InsertAtEnd)
   : TerminatorInst(Type::getVoidTy(IfTrue->getContext()), Instruction::Br,
                    OperandTraits<BranchInst>::op_end(this) - 1,
                    1, InsertAtEnd) {
-  assert(IfTrue != 0 && "Branch destination may not be null!");
+  assert(IfTrue && "Branch destination may not be null!");
   Op<-1>() = IfTrue;
 }
 
diff --git a/lib/IR/MDBuilder.cpp b/lib/IR/MDBuilder.cpp
index 1d8a83dae7f..65cdf388521 100644
--- a/lib/IR/MDBuilder.cpp
+++ b/lib/IR/MDBuilder.cpp
@@ -23,7 +23,7 @@ MDString *MDBuilder::createString(StringRef Str) {
 
 MDNode *MDBuilder::createFPMath(float Accuracy) {
   if (Accuracy == 0.0)
-    return 0;
+    return nullptr;
   assert(Accuracy > 0.0 && "Invalid fpmath accuracy!");
   Value *Op = ConstantFP::get(Type::getFloatTy(Context), Accuracy);
   return MDNode::get(Context, Op);
diff --git a/lib/IR/Metadata.cpp b/lib/IR/Metadata.cpp
index 39acbd81066..4d932d03962 100644
--- a/lib/IR/Metadata.cpp
+++ b/lib/IR/Metadata.cpp
@@ -164,10 +164,10 @@ static const Function *getFunctionForValue(Value *V) {
 
 #ifndef NDEBUG
 static const Function *assertLocalFunction(const MDNode *N) {
-  if (!N->isFunctionLocal()) return 0;
+  if (!N->isFunctionLocal()) return nullptr;
 
   // FIXME: This does not handle cyclic function local metadata.
-  const Function *F = 0, *NewF = 0;
+  const Function *F = nullptr, *NewF = nullptr;
   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
     if (Value *V = N->getOperand(i)) {
       if (MDNode *MD = dyn_cast<MDNode>(V))
@@ -175,10 +175,11 @@ static const Function *assertLocalFunction(const MDNode *N) {
       else
         NewF = getFunctionForValue(V);
     }
-    if (F == 0)
+    if (!F)
       F = NewF;
-    else 
-      assert((NewF == 0 || F == NewF) &&"inconsistent function-local metadata");
+    else
+      assert((NewF == nullptr || F == NewF) &&
+             "inconsistent function-local metadata");
   }
   return F;
 }
diff --git a/lib/IR/PassRegistry.cpp b/lib/IR/PassRegistry.cpp
index 7e6b47c9bfa..89f4f60f054 100644
--- a/lib/IR/PassRegistry.cpp
+++ b/lib/IR/PassRegistry.cpp
@@ -174,7 +174,7 @@ void PassRegistry::registerAnalysisGroup(const void *InterfaceID,
            "Cannot add a pass to the same analysis group more than once!");
     AGI.Implementations.insert(ImplementationInfo);
     if (isDefault) {
-      assert(InterfaceInfo->getNormalCtor() == 0 &&
+      assert(InterfaceInfo->getNormalCtor() == nullptr &&
              "Default implementation for analysis group already specified!");
       assert(ImplementationInfo->getNormalCtor() &&
            "Cannot specify pass as default if it does not have a default ctor");
diff --git a/lib/IR/Type.cpp b/lib/IR/Type.cpp
index 1316635a96b..1efde47b856 100644
--- a/lib/IR/Type.cpp
+++ b/lib/IR/Type.cpp
@@ -497,7 +497,7 @@ StructType *StructType::get(LLVMContext &Context, bool isPacked) {
 }
 
 StructType *StructType::get(Type *type, ...) {
-  assert(type != 0 && "Cannot create a struct type with no elements with this");
+  assert(type && "Cannot create a struct type with no elements with this");
   LLVMContext &Ctx = type->getContext();
   va_list ap;
   SmallVector<llvm::Type*, 8> StructFields;
@@ -538,7 +538,7 @@ StructType *StructType::create(ArrayRef<Type*> Elements) {
 }
 
 StructType *StructType::create(StringRef Name, Type *type, ...) {
-  assert(type != 0 && "Cannot create a struct type with no elements with this");
+  assert(type && "Cannot create a struct type with no elements with this");
   LLVMContext &Ctx = type->getContext();
   va_list ap;
   SmallVector<llvm::Type*, 8> StructFields;
@@ -582,7 +582,7 @@ StringRef StructType::getName() const {
 }
 
 void StructType::setBody(Type *type, ...) {
-  assert(type != 0 && "Cannot create a struct type with no elements with this");
+  assert(type && "Cannot create a struct type with no elements with this");
   va_list ap;
   SmallVector<llvm::Type*, 8> StructFields;
   va_start(ap, type);
diff --git a/lib/IR/Value.cpp b/lib/IR/Value.cpp
index 45f68ac35ff..2ebdb702cf9 100644
--- a/lib/IR/Value.cpp
+++ b/lib/IR/Value.cpp
@@ -557,7 +557,7 @@ void ValueHandleBase::AddToUseList() {
     // If this value already has a ValueHandle, then it must be in the
     // ValueHandles map already.
     ValueHandleBase *&Entry = pImpl->ValueHandles[VP.getPointer()];
-    assert(Entry != 0 && "Value doesn't have any handles?");
+    assert(Entry && "Value doesn't have any handles?");
     AddToExistingUseList(&Entry);
     return;
   }
@@ -571,7 +571,7 @@ void ValueHandleBase::AddToUseList() {
   const void *OldBucketPtr = Handles.getPointerIntoBucketsArray();
 
   ValueHandleBase *&Entry = Handles[VP.getPointer()];
-  assert(Entry == 0 && "Value really did already have handles?");
+  assert(!Entry && "Value really did already have handles?");
   AddToExistingUseList(&Entry);
   VP.getPointer()->HasValueHandle = true;
 
diff --git a/lib/IRReader/IRReader.cpp b/lib/IRReader/IRReader.cpp
index 8be8ab882e7..f4ed4376938 100644
--- a/lib/IRReader/IRReader.cpp
+++ b/lib/IRReader/IRReader.cpp
@@ -42,12 +42,12 @@ Module *llvm::getLazyIRModule(MemoryBuffer *Buffer, SMDiagnostic &Err,
       // ParseBitcodeFile does not take ownership of the Buffer in the
       // case of an error.
       delete Buffer;
-      return NULL;
+      return nullptr;
     }
     return ModuleOrErr.get();
   }
 
-  return ParseAssembly(Buffer, 0, Err, Context);
+  return ParseAssembly(Buffer, nullptr, Err, Context);
 }
 
 Module *llvm::getLazyIRFileModule(const std::string &Filename, SMDiagnostic &Err,
@@ -56,7 +56,7 @@ Module *llvm::getLazyIRFileModule(const std::string &Filename, SMDiagnostic &Err
   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, File)) {
     Err = SMDiagnostic(Filename, SourceMgr::DK_Error,
                        "Could not open input file: " + ec.message());
-    return 0;
+    return nullptr;
   }
 
   return getLazyIRModule(File.release(), Err, Context);
@@ -69,7 +69,7 @@ Module *llvm::ParseIR(MemoryBuffer *Buffer, SMDiagnostic &Err,
   if (isBitcode((const unsigned char *)Buffer->getBufferStart(),
                 (const unsigned char *)Buffer->getBufferEnd())) {
     ErrorOr<Module *> ModuleOrErr = parseBitcodeFile(Buffer, Context);
-    Module *M = 0;
+    Module *M = nullptr;
     if (error_code EC = ModuleOrErr.getError())
       Err = SMDiagnostic(Buffer->getBufferIdentifier(), SourceMgr::DK_Error,
                          EC.message());
@@ -80,7 +80,7 @@ Module *llvm::ParseIR(MemoryBuffer *Buffer, SMDiagnostic &Err,
     return M;
   }
 
-  return ParseAssembly(Buffer, 0, Err, Context);
+  return ParseAssembly(Buffer, nullptr, Err, Context);
 }
 
 Module *llvm::ParseIRFile(const std::string &Filename, SMDiagnostic &Err,
@@ -89,7 +89,7 @@ Module *llvm::ParseIRFile(const std::string &Filename, SMDiagnostic &Err,
   if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, File)) {
     Err = SMDiagnostic(Filename, SourceMgr::DK_Error,
                        "Could not open input file: " + ec.message());
-    return 0;
+    return nullptr;
   }
 
   return ParseIR(File.release(), Err, Context);
@@ -111,7 +111,7 @@ LLVMBool LLVMParseIRInContext(LLVMContextRef ContextRef,
       std::string buf;
       raw_string_ostream os(buf);
 
-      Diag.print(NULL, os, false);
+      Diag.print(nullptr, os, false);
       os.flush();
 
       *OutMessage = strdup(buf.c_str());
diff --git a/lib/LTO/LTOCodeGenerator.cpp b/lib/LTO/LTOCodeGenerator.cpp
index 2ba90fad848..8df42772d5a 100644
--- a/lib/LTO/LTOCodeGenerator.cpp
+++ b/lib/LTO/LTOCodeGenerator.cpp
@@ -64,17 +64,17 @@ const char* LTOCodeGenerator::getVersionString() {
 
 LTOCodeGenerator::LTOCodeGenerator()
     : Context(getGlobalContext()), Linker(new Module("ld-temp.o", Context)),
-      TargetMach(NULL), EmitDwarfDebugInfo(false), ScopeRestrictionsDone(false),
-      CodeModel(LTO_CODEGEN_PIC_MODEL_DEFAULT), NativeObjectFile(NULL),
-      DiagHandler(NULL), DiagContext(NULL) {
+      TargetMach(nullptr), EmitDwarfDebugInfo(false),
+      ScopeRestrictionsDone(false), CodeModel(LTO_CODEGEN_PIC_MODEL_DEFAULT),
+      NativeObjectFile(nullptr), DiagHandler(nullptr), DiagContext(nullptr) {
   initializeLTOPasses();
 }
 
 LTOCodeGenerator::~LTOCodeGenerator() {
   delete TargetMach;
   delete NativeObjectFile;
-  TargetMach = NULL;
-  NativeObjectFile = NULL;
+  TargetMach = nullptr;
+  NativeObjectFile = nullptr;
 
   Linker.deleteModule();
 
@@ -245,7 +245,7 @@ const void* LTOCodeGenerator::compile(size_t* length,
   const char *name;
   if (!compile_to_file(&name, disableOpt, disableInline, disableGVNLoadPRE,
                        errMsg))
-    return NULL;
+    return nullptr;
 
   // remove old buffer if compile() called twice
   delete NativeObjectFile;
@@ -255,7 +255,7 @@ const void* LTOCodeGenerator::compile(size_t* length,
   if (error_code ec = MemoryBuffer::getFile(name, BuffPtr, -1, false)) {
     errMsg = ec.message();
     sys::fs::remove(NativeObjectPath);
-    return NULL;
+    return nullptr;
   }
   NativeObjectFile = BuffPtr.release();
 
@@ -263,14 +263,14 @@ const void* LTOCodeGenerator::compile(size_t* length,
   sys::fs::remove(NativeObjectPath);
 
   // return buffer, unless error
-  if (NativeObjectFile == NULL)
-    return NULL;
+  if (!NativeObjectFile)
+    return nullptr;
   *length = NativeObjectFile->getBufferSize();
   return NativeObjectFile->getBufferStart();
 }
 
 bool LTOCodeGenerator::determineTarget(std::string &errMsg) {
-  if (TargetMach != NULL)
+  if (TargetMach)
     return true;
 
   std::string TripleStr = Linker.getModule()->getTargetTriple();
@@ -280,7 +280,7 @@ bool LTOCodeGenerator::determineTarget(std::string &errMsg) {
 
   // create target machine from info for merged modules
   const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg);
-  if (march == NULL)
+  if (!march)
     return false;
 
   // The relocation model is actually a static member of TargetMachine and
@@ -355,7 +355,7 @@ applyRestriction(GlobalValue &GV,
 
 static void findUsedValues(GlobalVariable *LLVMUsed,
                            SmallPtrSet<GlobalValue*, 8> &UsedValues) {
-  if (LLVMUsed == 0) return;
+  if (!LLVMUsed) return;
 
   ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
   for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
@@ -579,7 +579,7 @@ LTOCodeGenerator::setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,
   this->DiagHandler = DiagHandler;
   this->DiagContext = Ctxt;
   if (!DiagHandler)
-    return Context.setDiagnosticHandler(NULL, NULL);
+    return Context.setDiagnosticHandler(nullptr, nullptr);
   // Register the LTOCodeGenerator stub in the LLVMContext to forward the
   // diagnostic to the external DiagHandler.
   Context.setDiagnosticHandler(LTOCodeGenerator::DiagnosticHandler, this);
diff --git a/lib/LTO/LTOModule.cpp b/lib/LTO/LTOModule.cpp
index 567da04f90c..3527b8bcfca 100644
--- a/lib/LTO/LTOModule.cpp
+++ b/lib/LTO/LTOModule.cpp
@@ -100,7 +100,7 @@ LTOModule *LTOModule::makeLTOModule(const char *path, TargetOptions options,
   std::unique_ptr<MemoryBuffer> buffer;
   if (error_code ec = MemoryBuffer::getFile(path, buffer)) {
     errMsg = ec.message();
-    return NULL;
+    return nullptr;
   }
   return makeLTOModule(buffer.release(), options, errMsg);
 }
@@ -120,7 +120,7 @@ LTOModule *LTOModule::makeLTOModule(int fd, const char *path,
   if (error_code ec =
           MemoryBuffer::getOpenFileSlice(fd, path, buffer, map_size, offset)) {
     errMsg = ec.message();
-    return NULL;
+    return nullptr;
   }
   return makeLTOModule(buffer.release(), options, errMsg);
 }
@@ -130,7 +130,7 @@ LTOModule *LTOModule::makeLTOModule(const void *mem, size_t length,
                                     std::string &errMsg, StringRef path) {
   std::unique_ptr<MemoryBuffer> buffer(makeBuffer(mem, length, path));
   if (!buffer)
-    return NULL;
+    return nullptr;
   return makeLTOModule(buffer.release(), options, errMsg);
 }
 
@@ -143,7 +143,7 @@ LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,
   if (error_code EC = ModuleOrErr.getError()) {
     errMsg = EC.message();
     delete buffer;
-    return NULL;
+    return nullptr;
   }
   std::unique_ptr<Module> m(ModuleOrErr.get());
 
@@ -155,7 +155,7 @@ LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,
   // find machine architecture for this module
   const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg);
   if (!march)
-    return NULL;
+    return nullptr;
 
   // construct LTOModule, hand over ownership of module and target
   SubtargetFeatures Features;
@@ -189,7 +189,7 @@ LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,
 
   if (Ret->parseSymbols(errMsg)) {
     delete Ret;
-    return NULL;
+    return nullptr;
   }
 
   Ret->parseMetadata();
@@ -460,7 +460,7 @@ void LTOModule::addAsmGlobalSymbol(const char *name,
 
   NameAndAttributes &info = _undefines[entry.getKey().data()];
 
-  if (info.symbol == 0) {
+  if (info.symbol == nullptr) {
     // FIXME: This is trying to take care of module ASM like this:
     //
     //   module asm ".zerofill __FOO, __foo, _bar_baz_qux, 0"
@@ -474,7 +474,7 @@ void LTOModule::addAsmGlobalSymbol(const char *name,
     info.attributes =
       LTO_SYMBOL_PERMISSIONS_DATA | LTO_SYMBOL_DEFINITION_REGULAR | scope;
     info.isFunction = false;
-    info.symbol = 0;
+    info.symbol = nullptr;
 
     // add to table of symbols
     _symbols.push_back(info);
@@ -508,7 +508,7 @@ void LTOModule::addAsmGlobalSymbolUndef(const char *name) {
   info.name = entry.getKey().data();
   info.attributes = attr;
   info.isFunction = false;
-  info.symbol = 0;
+  info.symbol = nullptr;
 
   entry.setValue(info);
 }
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index c6476ce7b84..581e8217dee 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -439,16 +439,16 @@ namespace {
       // If the source has no name it can't link.  If it has local linkage,
       // there is no name match-up going on.
       if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
-        return 0;
+        return nullptr;
       
       // Otherwise see if we have a match in the destination module's symtab.
       GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
-      if (DGV == 0) return 0;
+      if (!DGV) return nullptr;
         
       // If we found a global with the same name in the dest module, but it has
       // internal linkage, we are really not doing any linkage here.
       if (DGV->hasLocalLinkage())
-        return 0;
+        return nullptr;
 
       // Otherwise, we do in fact link to the destination global.
       return DGV;
@@ -518,7 +518,7 @@ static bool isLessConstraining(GlobalValue::VisibilityTypes a,
 Value *ValueMaterializerTy::materializeValueFor(Value *V) {
   Function *SF = dyn_cast<Function>(V);
   if (!SF)
-    return NULL;
+    return nullptr;
 
   Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()),
                                   SF->getLinkage(), SF->getName(), DstM);
@@ -612,7 +612,7 @@ void ModuleLinker::computeTypeMapping() {
   for (Module::global_iterator I = SrcM->global_begin(),
        E = SrcM->global_end(); I != E; ++I) {
     GlobalValue *DGV = getLinkedToGlobal(I);
-    if (DGV == 0) continue;
+    if (!DGV) continue;
     
     if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
       TypeMap.addTypeMapping(DGV->getType(), I->getType());
@@ -723,7 +723,7 @@ bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
   // Create the new global variable.
   GlobalVariable *NG =
     new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
-                       DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
+                       DstGV->getLinkage(), /*init*/nullptr, /*name*/"", DstGV,
                        DstGV->getThreadLocalMode(),
                        DstGV->getType()->getAddressSpace());
   
@@ -800,8 +800,8 @@ bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
   // initializer will be filled in later by LinkGlobalInits.
   GlobalVariable *NewDGV =
     new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
-                       SGV->isConstant(), SGV->getLinkage(), /*init*/0,
-                       SGV->getName(), /*insertbefore*/0,
+                       SGV->isConstant(), SGV->getLinkage(), /*init*/nullptr,
+                       SGV->getName(), /*insertbefore*/nullptr,
                        SGV->getThreadLocalMode(),
                        SGV->getType()->getAddressSpace());
   // Propagate alignment, visibility and section info.
@@ -913,7 +913,7 @@ bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
   // bring over SGA.
   GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
                                        SGA->getLinkage(), SGA->getName(),
-                                       /*aliasee*/0, DstM);
+                                       /*aliasee*/nullptr, DstM);
   copyGVAttributes(NewDA, SGA);
   if (NewVisibility)
     NewDA->setVisibility(*NewVisibility);
@@ -997,7 +997,7 @@ void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
   } else {
     // Clone the body of the function into the dest function.
     SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
-    CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL,
+    CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", nullptr,
                       &TypeMap, &ValMaterializer);
   }
   
@@ -1369,7 +1369,7 @@ Linker::~Linker() {
 
 void Linker::deleteModule() {
   delete Composite;
-  Composite = NULL;
+  Composite = nullptr;
 }
 
 bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) {
@@ -1406,7 +1406,7 @@ LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
                          LLVMLinkerMode Mode, char **OutMessages) {
   std::string Messages;
   LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src),
-                                        Mode, OutMessages? &Messages : 0);
+                                        Mode, OutMessages? &Messages : nullptr);
   if (OutMessages)
     *OutMessages = strdup(Messages.c_str());
   return Result;
diff --git a/lib/Object/Archive.cpp b/lib/Object/Archive.cpp
index 999bf28bb38..d53704fa799 100644
--- a/lib/Object/Archive.cpp
+++ b/lib/Object/Archive.cpp
@@ -111,7 +111,7 @@ Archive::Child Archive::Child::getNext() const {
 
   // Check to see if this is past the end of the archive.
   if (NextLoc >= Parent->Data->getBufferEnd())
-    return Child(Parent, NULL);
+    return Child(Parent, nullptr);
 
   return Child(Parent, NextLoc);
 }
@@ -349,7 +349,7 @@ Archive::child_iterator Archive::child_begin(bool SkipInternal) const {
 }
 
 Archive::child_iterator Archive::child_end() const {
-  return Child(this, NULL);
+  return Child(this, nullptr);
 }
 
 error_code Archive::Symbol::getName(StringRef &Result) const {
diff --git a/lib/Object/COFFObjectFile.cpp b/lib/Object/COFFObjectFile.cpp
index 601fd8c613e..262c040c57a 100644
--- a/lib/Object/COFFObjectFile.cpp
+++ b/lib/Object/COFFObjectFile.cpp
@@ -138,7 +138,7 @@ error_code COFFObjectFile::getSymbolName(DataRefImpl Ref,
 error_code COFFObjectFile::getSymbolAddress(DataRefImpl Ref,
                                             uint64_t &Result) const {
   const coff_symbol *Symb = toSymb(Ref);
-  const coff_section *Section = NULL;
+  const coff_section *Section = nullptr;
   if (error_code EC = getSection(Symb->SectionNumber, Section))
     return EC;
 
@@ -163,7 +163,7 @@ error_code COFFObjectFile::getSymbolType(DataRefImpl Ref,
   } else {
     uint32_t Characteristics = 0;
     if (!COFF::isReservedSectionNumber(Symb->SectionNumber)) {
-      const coff_section *Section = NULL;
+      const coff_section *Section = nullptr;
       if (error_code EC = getSection(Symb->SectionNumber, Section))
         return EC;
       Characteristics = Section->Characteristics;
@@ -208,7 +208,7 @@ error_code COFFObjectFile::getSymbolSize(DataRefImpl Ref,
   //        in the same section as this symbol, and looking for either the next
   //        symbol, or the end of the section.
   const coff_symbol *Symb = toSymb(Ref);
-  const coff_section *Section = NULL;
+  const coff_section *Section = nullptr;
   if (error_code EC = getSection(Symb->SectionNumber, Section))
     return EC;
 
@@ -227,7 +227,7 @@ error_code COFFObjectFile::getSymbolSection(DataRefImpl Ref,
   if (COFF::isReservedSectionNumber(Symb->SectionNumber)) {
     Result = section_end();
   } else {
-    const coff_section *Sec = 0;
+    const coff_section *Sec = nullptr;
     if (error_code EC = getSection(Symb->SectionNumber, Sec)) return EC;
     DataRefImpl Ref;
     Ref.p = reinterpret_cast<uintptr_t>(Sec);
@@ -334,7 +334,7 @@ error_code COFFObjectFile::sectionContainsSymbol(DataRefImpl SecRef,
                                                  bool &Result) const {
   const coff_section *Sec = toSec(SecRef);
   const coff_symbol *Symb = toSymb(SymbRef);
-  const coff_section *SymbSec = 0;
+  const coff_section *SymbSec = nullptr;
   if (error_code EC = getSection(Symb->SectionNumber, SymbSec)) return EC;
   if (SymbSec == Sec)
     Result = true;
@@ -507,10 +507,11 @@ error_code COFFObjectFile::initExportTablePtr() {
 
 COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &EC,
                                bool BufferOwned)
-    : ObjectFile(Binary::ID_COFF, Object, BufferOwned), COFFHeader(0),
-      PE32Header(0), PE32PlusHeader(0), DataDirectory(0), SectionTable(0),
-      SymbolTable(0), StringTable(0), StringTableSize(0), ImportDirectory(0),
-      NumberOfImportDirectory(0), ExportDirectory(0) {
+    : ObjectFile(Binary::ID_COFF, Object, BufferOwned), COFFHeader(nullptr),
+      PE32Header(nullptr), PE32PlusHeader(nullptr), DataDirectory(nullptr),
+      SectionTable(nullptr), SymbolTable(nullptr), StringTable(nullptr),
+      StringTableSize(0), ImportDirectory(nullptr), NumberOfImportDirectory(0),
+      ExportDirectory(nullptr) {
   // Check that we at least have enough room for a header.
   if (!checkSize(Data, EC, sizeof(coff_file_header))) return;
 
@@ -632,8 +633,8 @@ export_directory_iterator COFFObjectFile::export_directory_begin() const {
 }
 
 export_directory_iterator COFFObjectFile::export_directory_end() const {
-  if (ExportDirectory == 0)
-    return export_directory_iterator(ExportDirectoryEntryRef(0, 0, this));
+  if (!ExportDirectory)
+    return export_directory_iterator(ExportDirectoryEntryRef(nullptr, 0, this));
   ExportDirectoryEntryRef Ref(ExportDirectory,
                               ExportDirectory->AddressTableEntries, this);
   return export_directory_iterator(Ref);
@@ -723,7 +724,7 @@ error_code COFFObjectFile::getSection(int32_t Index,
                                       const coff_section *&Result) const {
   // Check for special index values.
   if (COFF::isReservedSectionNumber(Index))
-    Result = NULL;
+    Result = nullptr;
   else if (Index > 0 && Index <= COFFHeader->NumberOfSections)
     // We already verified the section table data, so no need to check again.
     Result = SectionTable + (Index - 1);
@@ -773,7 +774,7 @@ error_code COFFObjectFile::getSymbolName(const coff_symbol *Symbol,
 
 ArrayRef<uint8_t> COFFObjectFile::getSymbolAuxData(
                                   const coff_symbol *Symbol) const {
-  const uint8_t *Aux = NULL;
+  const uint8_t *Aux = nullptr;
 
   if (Symbol->NumberOfAuxSymbols > 0) {
   // AUX data comes immediately after the symbol in COFF
@@ -968,7 +969,7 @@ error_code COFFObjectFile::getRelocationTypeName(DataRefImpl Rel,
 error_code COFFObjectFile::getRelocationValueString(DataRefImpl Rel,
                                           SmallVectorImpl<char> &Result) const {
   const coff_relocation *Reloc = toRel(Rel);
-  const coff_symbol *Symb = 0;
+  const coff_symbol *Symb = nullptr;
   if (error_code EC = getSymbol(Reloc->SymbolTableIndex, Symb)) return EC;
   DataRefImpl Sym;
   Sym.p = reinterpret_cast<uintptr_t>(Symb);
diff --git a/lib/Object/MachOObjectFile.cpp b/lib/Object/MachOObjectFile.cpp
index ce4b3d5d0c1..d0a56aa930e 100644
--- a/lib/Object/MachOObjectFile.cpp
+++ b/lib/Object/MachOObjectFile.cpp
@@ -420,7 +420,8 @@ MachOObjectFile::MachOObjectFile(MemoryBuffer *Object, bool IsLittleEndian,
                                  bool Is64bits, error_code &EC,
                                  bool BufferOwned)
     : ObjectFile(getMachOType(IsLittleEndian, Is64bits), Object, BufferOwned),
-      SymtabLoadCmd(NULL), DysymtabLoadCmd(NULL), DataInCodeLoadCmd(NULL) {
+      SymtabLoadCmd(nullptr), DysymtabLoadCmd(nullptr),
+      DataInCodeLoadCmd(nullptr) {
   uint32_t LoadCommandCount = this->getHeader().ncmds;
   MachO::LoadCommandType SegmentLoadType = is64Bit() ?
     MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
diff --git a/lib/Object/MachOUniversal.cpp b/lib/Object/MachOUniversal.cpp
index 70baa9f63a6..3f3731f22d8 100644
--- a/lib/Object/MachOUniversal.cpp
+++ b/lib/Object/MachOUniversal.cpp
@@ -57,7 +57,7 @@ static T getUniversalBinaryStruct(const char *Ptr) {
 MachOUniversalBinary::ObjectForArch::ObjectForArch(
     const MachOUniversalBinary *Parent, uint32_t Index)
     : Parent(Parent), Index(Index) {
-  if (Parent == 0 || Index > Parent->getNumberOfObjects()) {
+  if (!Parent || Index > Parent->getNumberOfObjects()) {
     clear();
   } else {
     // Parse object header.
diff --git a/lib/Object/Object.cpp b/lib/Object/Object.cpp
index 243bd44a02c..afba55340da 100644
--- a/lib/Object/Object.cpp
+++ b/lib/Object/Object.cpp
@@ -60,7 +60,7 @@ wrap(const relocation_iterator *SI) {
 // ObjectFile creation
 LLVMObjectFileRef LLVMCreateObjectFile(LLVMMemoryBufferRef MemBuf) {
   ErrorOr<ObjectFile*> ObjOrErr(ObjectFile::createObjectFile(unwrap(MemBuf)));
-  ObjectFile *Obj = ObjOrErr ? ObjOrErr.get() : 0;
+  ObjectFile *Obj = ObjOrErr ? ObjOrErr.get() : nullptr;
   return wrap(Obj);
 }
 
diff --git a/lib/Option/ArgList.cpp b/lib/Option/ArgList.cpp
index fecd2371735..1b013f2c02a 100644
--- a/lib/Option/ArgList.cpp
+++ b/lib/Option/ArgList.cpp
@@ -60,11 +60,11 @@ Arg *ArgList::getLastArgNoClaim(OptSpecifier Id) const {
   for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it)
     if ((*it)->getOption().matches(Id))
       return *it;
-  return 0;
+  return nullptr;
 }
 
 Arg *ArgList::getLastArg(OptSpecifier Id) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id)) {
       Res = *it;
@@ -76,7 +76,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id) const {
 }
 
 Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1)) {
@@ -91,7 +91,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1) const {
 
 Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
                          OptSpecifier Id2) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1) ||
@@ -106,7 +106,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
 
 Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
                          OptSpecifier Id2, OptSpecifier Id3) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1) ||
@@ -123,7 +123,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
 Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
                          OptSpecifier Id2, OptSpecifier Id3,
                          OptSpecifier Id4) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1) ||
@@ -141,7 +141,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
 Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
                          OptSpecifier Id2, OptSpecifier Id3,
                          OptSpecifier Id4, OptSpecifier Id5) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1) ||
@@ -161,7 +161,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
                          OptSpecifier Id2, OptSpecifier Id3,
                          OptSpecifier Id4, OptSpecifier Id5,
                          OptSpecifier Id6) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1) ||
@@ -182,7 +182,7 @@ Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
                          OptSpecifier Id2, OptSpecifier Id3,
                          OptSpecifier Id4, OptSpecifier Id5,
                          OptSpecifier Id6, OptSpecifier Id7) const {
-  Arg *Res = 0;
+  Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1) ||
diff --git a/lib/Option/OptTable.cpp b/lib/Option/OptTable.cpp
index 6fa459a0066..6842f4d5791 100644
--- a/lib/Option/OptTable.cpp
+++ b/lib/Option/OptTable.cpp
@@ -62,7 +62,7 @@ static inline bool operator<(const OptTable::Info &A, const OptTable::Info &B) {
 
   for (const char * const *APre = A.Prefixes,
                   * const *BPre = B.Prefixes;
-                          *APre != 0 && *BPre != 0; ++APre, ++BPre) {
+                          *APre != nullptr && *BPre != nullptr; ++APre, ++BPre){
     if (int N = StrCmpOptionName(*APre, *BPre))
       return N < 0;
   }
@@ -136,7 +136,7 @@ OptTable::OptTable(const Info *_OptionInfos, unsigned _NumOptionInfos,
   for (unsigned i = FirstSearchableIndex + 1, e = getNumOptions() + 1;
                 i != e; ++i) {
     if (const char *const *P = getInfo(i).Prefixes) {
-      for (; *P != 0; ++P) {
+      for (; *P != nullptr; ++P) {
         PrefixesUnion.insert(*P);
       }
     }
@@ -160,7 +160,7 @@ OptTable::~OptTable() {
 const Option OptTable::getOption(OptSpecifier Opt) const {
   unsigned id = Opt.getID();
   if (id == 0)
-    return Option(0, 0);
+    return Option(nullptr, nullptr);
   assert((unsigned) (id - 1) < getNumOptions() && "Invalid ID.");
   return Option(&getInfo(id), this);
 }
@@ -178,7 +178,7 @@ static bool isInput(const llvm::StringSet<> &Prefixes, StringRef Arg) {
 /// \returns Matched size. 0 means no match.
 static unsigned matchOption(const OptTable::Info *I, StringRef Str,
                             bool IgnoreCase) {
-  for (const char * const *Pre = I->Prefixes; *Pre != 0; ++Pre) {
+  for (const char * const *Pre = I->Prefixes; *Pre != nullptr; ++Pre) {
     StringRef Prefix(*Pre);
     if (Str.startswith(Prefix)) {
       StringRef Rest = Str.substr(Prefix.size());
@@ -240,7 +240,7 @@ Arg *OptTable::ParseOneArg(const ArgList &Args, unsigned &Index,
 
     // Otherwise, see if this argument was missing values.
     if (Prev != Index)
-      return 0;
+      return nullptr;
   }
 
   // If we failed to find an option and this arg started with /, then it's
diff --git a/lib/Option/Option.cpp b/lib/Option/Option.cpp
index 7b5ff2be9a7..10662a33c27 100644
--- a/lib/Option/Option.cpp
+++ b/lib/Option/Option.cpp
@@ -58,8 +58,8 @@ void Option::dump() const {
 
   if (Info->Prefixes) {
     llvm::errs() << " Prefixes:[";
-    for (const char * const *Pre = Info->Prefixes; *Pre != 0; ++Pre) {
-      llvm::errs() << '"' << *Pre << (*(Pre + 1) == 0 ? "\"" : "\", ");
+    for (const char * const *Pre = Info->Prefixes; *Pre != nullptr; ++Pre) {
+      llvm::errs() << '"' << *Pre << (*(Pre + 1) == nullptr ? "\"" : "\", ");
     }
     llvm::errs() << ']';
   }
@@ -116,7 +116,7 @@ Arg *Option::accept(const ArgList &Args,
   switch (getKind()) {
   case FlagClass: {
     if (ArgSize != strlen(Args.getArgString(Index)))
-      return 0;
+      return nullptr;
 
     Arg *A = new Arg(UnaliasedOption, Spelling, Index++);
     if (getAliasArgs()) {
@@ -166,11 +166,11 @@ Arg *Option::accept(const ArgList &Args,
     // Matches iff this is an exact match.
     // FIXME: Avoid strlen.
     if (ArgSize != strlen(Args.getArgString(Index)))
-      return 0;
+      return nullptr;
 
     Index += 2;
     if (Index > Args.getNumInputArgStrings())
-      return 0;
+      return nullptr;
 
     return new Arg(UnaliasedOption, Spelling,
                    Index - 2, Args.getArgString(Index - 1));
@@ -178,11 +178,11 @@ Arg *Option::accept(const ArgList &Args,
     // Matches iff this is an exact match.
     // FIXME: Avoid strlen.
     if (ArgSize != strlen(Args.getArgString(Index)))
-      return 0;
+      return nullptr;
 
     Index += 1 + getNumArgs();
     if (Index > Args.getNumInputArgStrings())
-      return 0;
+      return nullptr;
 
     Arg *A = new Arg(UnaliasedOption, Spelling, Index - 1 - getNumArgs(),
                       Args.getArgString(Index - getNumArgs()));
@@ -201,7 +201,7 @@ Arg *Option::accept(const ArgList &Args,
     // Otherwise it must be separate.
     Index += 2;
     if (Index > Args.getNumInputArgStrings())
-      return 0;
+      return nullptr;
 
     return new Arg(UnaliasedOption, Spelling,
                    Index - 2, Args.getArgString(Index - 1));
@@ -210,7 +210,7 @@ Arg *Option::accept(const ArgList &Args,
     // Always matches.
     Index += 2;
     if (Index > Args.getNumInputArgStrings())
-      return 0;
+      return nullptr;
 
     return new Arg(UnaliasedOption, Spelling, Index - 2,
                    Args.getArgString(Index - 2) + ArgSize,
@@ -219,7 +219,7 @@ Arg *Option::accept(const ArgList &Args,
     // Matches iff this is an exact match.
     // FIXME: Avoid strlen.
     if (ArgSize != strlen(Args.getArgString(Index)))
-      return 0;
+      return nullptr;
     Arg *A = new Arg(UnaliasedOption, Spelling, Index++);
     while (Index < Args.getNumInputArgStrings())
       A->getValues().push_back(Args.getArgString(Index++));
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index e1fd3c602b7..f9fe09541db 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -1358,7 +1358,7 @@ APFloat::addOrSubtractSpecials(const APFloat &rhs, bool subtract)
 {
   switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
-    llvm_unreachable(0);
+    llvm_unreachable(nullptr);
 
   case PackCategoriesIntoKey(fcNaN, fcZero):
   case PackCategoriesIntoKey(fcNaN, fcNormal):
@@ -1485,7 +1485,7 @@ APFloat::multiplySpecials(const APFloat &rhs)
 {
   switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
-    llvm_unreachable(0);
+    llvm_unreachable(nullptr);
 
   case PackCategoriesIntoKey(fcNaN, fcZero):
   case PackCategoriesIntoKey(fcNaN, fcNormal):
@@ -1529,7 +1529,7 @@ APFloat::divideSpecials(const APFloat &rhs)
 {
   switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
-    llvm_unreachable(0);
+    llvm_unreachable(nullptr);
 
   case PackCategoriesIntoKey(fcZero, fcNaN):
   case PackCategoriesIntoKey(fcNormal, fcNaN):
@@ -1570,7 +1570,7 @@ APFloat::modSpecials(const APFloat &rhs)
 {
   switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
-    llvm_unreachable(0);
+    llvm_unreachable(nullptr);
 
   case PackCategoriesIntoKey(fcNaN, fcZero):
   case PackCategoriesIntoKey(fcNaN, fcNormal):
@@ -1882,7 +1882,7 @@ APFloat::compare(const APFloat &rhs) const
 
   switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
-    llvm_unreachable(0);
+    llvm_unreachable(nullptr);
 
   case PackCategoriesIntoKey(fcNaN, fcZero):
   case PackCategoriesIntoKey(fcNaN, fcNormal):
@@ -3331,7 +3331,7 @@ APFloat::initFromAPInt(const fltSemantics* Sem, const APInt& api)
   if (Sem == &PPCDoubleDouble)
     return initFromPPCDoubleDoubleAPInt(api);
 
-  llvm_unreachable(0);
+  llvm_unreachable(nullptr);
 }
 
 APFloat
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index 4777616b952..2b4c43104bb 100644
--- a/lib/Support/CommandLine.cpp
+++ b/lib/Support/CommandLine.cpp
@@ -103,7 +103,7 @@ void cl::MarkOptionsChanged() {
 static Option *RegisteredOptionList = nullptr;
 
 void Option::addArgument() {
-  assert(NextRegistered == 0 && "argument multiply registered!");
+  assert(!NextRegistered && "argument multiply registered!");
 
   NextRegistered = RegisteredOptionList;
   RegisteredOptionList = this;
@@ -111,7 +111,7 @@ void Option::addArgument() {
 }
 
 void Option::removeArgument() {
-  assert(NextRegistered != 0 && "argument never registered");
+  assert(NextRegistered && "argument never registered");
   assert(RegisteredOptionList == this && "argument is not the last registered");
   RegisteredOptionList = NextRegistered;
   MarkOptionsChanged();
diff --git a/lib/Support/Debug.cpp b/lib/Support/Debug.cpp
index d9cb8a9da81..ad4d4ef1d92 100644
--- a/lib/Support/Debug.cpp
+++ b/lib/Support/Debug.cpp
@@ -109,7 +109,7 @@ raw_ostream &llvm::dbgs() {
       if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0)
         // TODO: Add a handler for SIGUSER1-type signals so the user can
         // force a debug dump.
-        sys::AddSignalHandler(&debug_user_sig_handler, 0);
+        sys::AddSignalHandler(&debug_user_sig_handler, nullptr);
       // Otherwise we've already set the debug stream buffer size to
       // zero, disabling buffering so it will output directly to errs().
     }
diff --git a/lib/Support/FoldingSet.cpp b/lib/Support/FoldingSet.cpp
index d857559898e..46351140875 100644
--- a/lib/Support/FoldingSet.cpp
+++ b/lib/Support/FoldingSet.cpp
@@ -305,7 +305,7 @@ FoldingSetImpl::Node
 /// is not already in the map.  InsertPos must be obtained from 
 /// FindNodeOrInsertPos.
 void FoldingSetImpl::InsertNode(Node *N, void *InsertPos) {
-  assert(N->getNextInBucket() == 0);
+  assert(!N->getNextInBucket());
   // Do we need to grow the hashtable?
   if (NumNodes+1 > NumBuckets*2) {
     GrowHashTable();
diff --git a/lib/Support/ManagedStatic.cpp b/lib/Support/ManagedStatic.cpp
index c05cd22ea05..acd5b1a7018 100644
--- a/lib/Support/ManagedStatic.cpp
+++ b/lib/Support/ManagedStatic.cpp
@@ -45,7 +45,7 @@ void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
 
     llvm_release_global_lock();
   } else {
-    assert(Ptr == 0 && DeleterFn == 0 && Next == 0 &&
+    assert(!Ptr && !DeleterFn && !Next &&
            "Partially initialized ManagedStatic!?");
     Ptr = Creator ? Creator() : nullptr;
     DeleterFn = Deleter;
diff --git a/lib/Support/Mutex.cpp b/lib/Support/Mutex.cpp
index 292d32a2fb1..c8d3844d0c9 100644
--- a/lib/Support/Mutex.cpp
+++ b/lib/Support/Mutex.cpp
@@ -75,7 +75,7 @@ MutexImpl::MutexImpl( bool recursive)
 MutexImpl::~MutexImpl()
 {
   pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
-  assert(mutex != 0);
+  assert(mutex != nullptr);
   pthread_mutex_destroy(mutex);
   free(mutex);
 }
@@ -84,7 +84,7 @@ bool
 MutexImpl::acquire()
 {
   pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
-  assert(mutex != 0);
+  assert(mutex != nullptr);
 
   int errorcode = pthread_mutex_lock(mutex);
   return errorcode == 0;
@@ -94,7 +94,7 @@ bool
 MutexImpl::release()
 {
   pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
-  assert(mutex != 0);
+  assert(mutex != nullptr);
 
   int errorcode = pthread_mutex_unlock(mutex);
   return errorcode == 0;
@@ -104,7 +104,7 @@ bool
 MutexImpl::tryacquire()
 {
   pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
-  assert(mutex != 0);
+  assert(mutex != nullptr);
 
   int errorcode = pthread_mutex_trylock(mutex);
   return errorcode == 0;
diff --git a/lib/Support/RWMutex.cpp b/lib/Support/RWMutex.cpp
index f42be5af50f..3b6309cef21 100644
--- a/lib/Support/RWMutex.cpp
+++ b/lib/Support/RWMutex.cpp
@@ -68,7 +68,7 @@ RWMutexImpl::RWMutexImpl()
 RWMutexImpl::~RWMutexImpl()
 {
   pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
-  assert(rwlock != 0);
+  assert(rwlock != nullptr);
   pthread_rwlock_destroy(rwlock);
   free(rwlock);
 }
@@ -77,7 +77,7 @@ bool
 RWMutexImpl::reader_acquire()
 {
   pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
-  assert(rwlock != 0);
+  assert(rwlock != nullptr);
 
   int errorcode = pthread_rwlock_rdlock(rwlock);
   return errorcode == 0;
@@ -87,7 +87,7 @@ bool
 RWMutexImpl::reader_release()
 {
   pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
-  assert(rwlock != 0);
+  assert(rwlock != nullptr);
 
   int errorcode = pthread_rwlock_unlock(rwlock);
   return errorcode == 0;
@@ -97,7 +97,7 @@ bool
 RWMutexImpl::writer_acquire()
 {
   pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
-  assert(rwlock != 0);
+  assert(rwlock != nullptr);
 
   int errorcode = pthread_rwlock_wrlock(rwlock);
   return errorcode == 0;
@@ -107,7 +107,7 @@ bool
 RWMutexImpl::writer_release()
 {
   pthread_rwlock_t* rwlock = static_cast<pthread_rwlock_t*>(data_);
-  assert(rwlock != 0);
+  assert(rwlock != nullptr);
 
   int errorcode = pthread_rwlock_unlock(rwlock);
   return errorcode == 0;
diff --git a/lib/Support/Timer.cpp b/lib/Support/Timer.cpp
index ea75d45f68a..eb3ffc44c8e 100644
--- a/lib/Support/Timer.cpp
+++ b/lib/Support/Timer.cpp
@@ -100,7 +100,7 @@ static TimerGroup *getDefaultTimerGroup() {
 //===----------------------------------------------------------------------===//
 
 void Timer::init(StringRef N) {
-  assert(TG == 0 && "Timer already initialized");
+  assert(!TG && "Timer already initialized");
   Name.assign(N.begin(), N.end());
   Started = false;
   TG = getDefaultTimerGroup();
@@ -108,7 +108,7 @@ void Timer::init(StringRef N) {
 }
 
 void Timer::init(StringRef N, TimerGroup &tg) {
-  assert(TG == 0 && "Timer already initialized");
+  assert(!TG && "Timer already initialized");
   Name.assign(N.begin(), N.end());
   Started = false;
   TG = &tg;
diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index 3c45743666d..f55838e660f 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -87,8 +87,8 @@ void raw_ostream::SetBuffered() {
 
 void raw_ostream::SetBufferAndMode(char *BufferStart, size_t Size,
                                    BufferKind Mode) {
-  assert(((Mode == Unbuffered && BufferStart == 0 && Size == 0) ||
-          (Mode != Unbuffered && BufferStart && Size)) &&
+  assert(((Mode == Unbuffered && !BufferStart && Size == 0) ||
+          (Mode != Unbuffered && BufferStart && Size != 0)) &&
          "stream must be unbuffered or have at least one byte");
   // Make sure the current buffer is free of content (we can't flush here; the
   // child buffer management logic will be in write_impl).
@@ -433,7 +433,7 @@ void format_object_base::home() {
 raw_fd_ostream::raw_fd_ostream(const char *Filename, std::string &ErrorInfo,
                                sys::fs::OpenFlags Flags)
     : Error(false), UseAtomicWrites(false), pos(0) {
-  assert(Filename != 0 && "Filename is null");
+  assert(Filename && "Filename is null");
   ErrorInfo.clear();
 
   // Handle "-" as stdout. Note that when we do this, we consider ourself