Revert "[llvm][NFC] Use c++17 style variable type traits"

This reverts commit 1834a31.

Author: njames93

llvm/include/llvm/Support/YAMLTraits.h

@@ -2019,8 +2019,9 @@ template <typename T> struct StdMapStringCustomMappingTraitsImpl {
   namespace llvm {                                                             \
   namespace yaml {                                                             \
   static_assert(                                                               \
-      !std::is_fundamental_v<TYPE> && !std::is_same_v<TYPE, std::string> &&    \
-          !std::is_same_v<TYPE, llvm::StringRef>,                              \
+      !std::is_fundamental<TYPE>::value &&                                     \
+      !std::is_same<TYPE, std::string>::value &&                               \
+      !std::is_same<TYPE, llvm::StringRef>::value,                             \
       "only use LLVM_YAML_IS_SEQUENCE_VECTOR for types you control");          \
   template <> struct SequenceElementTraits<TYPE> {                             \
     static const bool flow = FLOW;                                             \

llvm/lib/CodeGen/LiveDebugValues/VarLocBasedImpl.cpp

@@ -237,7 +237,8 @@ struct LocIndex {
   }
 
   template<typename IntT> static LocIndex fromRawInteger(IntT ID) {
-    static_assert(std::is_unsigned_v<IntT> && sizeof(ID) == sizeof(uint64_t),
+    static_assert(std::is_unsigned<IntT>::value &&
+                      sizeof(ID) == sizeof(uint64_t),
                   "Cannot convert raw integer to LocIndex");
     return {static_cast<u32_location_t>(ID >> 32),
             static_cast<u32_index_t>(ID)};

llvm/lib/DebugInfo/CodeView/EnumTables.cpp

@@ -14,7 +14,7 @@ using namespace llvm;
 using namespace codeview;
 
 #define CV_ENUM_CLASS_ENT(enum_class, enum)                                    \
-  { #enum, std::underlying_type_t<enum_class>(enum_class::enum) }
+  { #enum, std::underlying_type < enum_class > ::type(enum_class::enum) }
 
 #define CV_ENUM_ENT(ns, enum)                                                  \
   { #enum, ns::enum }

llvm/lib/DebugInfo/CodeView/TypeDumpVisitor.cpp

@@ -27,7 +27,7 @@ static const EnumEntry<TypeLeafKind> LeafTypeNames[] = {
 };
 
 #define ENUM_ENTRY(enum_class, enum)                                           \
-  { #enum, std::underlying_type_t<enum_class>(enum_class::enum) }
+  { #enum, std::underlying_type < enum_class > ::type(enum_class::enum) }
 
 static const EnumEntry<uint16_t> ClassOptionNames[] = {
     ENUM_ENTRY(ClassOptions, Packed),

llvm/lib/DebugInfo/PDB/Native/EnumTables.cpp

@@ -14,7 +14,7 @@ using namespace llvm;
 using namespace llvm::pdb;
 
 #define PDB_ENUM_CLASS_ENT(enum_class, enum)                                   \
-  { #enum, std::underlying_type_t<enum_class>(enum_class::enum) }
+  { #enum, std::underlying_type < enum_class > ::type(enum_class::enum) }
 
 #define PDB_ENUM_ENT(ns, enum)                                                 \
   { #enum, ns::enum }

llvm/lib/Object/DXContainer.cpp

@@ -32,7 +32,7 @@ static Error readStruct(StringRef Buffer, const char *Src, T &Struct) {
 
 template <typename T>
 static Error readInteger(StringRef Buffer, const char *Src, T &Val) {
-  static_assert(std::is_integral_v<T>,
+  static_assert(std::is_integral<T>::value,
                 "Cannot call readInteger on non-integral type.");
   // Don't read before the beginning or past the end of the file
   if (Src < Buffer.begin() || Src + sizeof(T) > Buffer.end())

llvm/lib/ProfileData/InstrProf.cpp

@@ -1351,7 +1351,7 @@ uint64_t Header::formatVersion() const {
 
 Expected<Header> Header::readFromBuffer(const unsigned char *Buffer) {
   using namespace support;
-  static_assert(std::is_standard_layout_v<Header>,
+  static_assert(std::is_standard_layout<Header>::value,
                 "The header should be standard layout type since we use offset "
                 "of fields to read.");
   Header H;

llvm/lib/Support/ItaniumManglingCanonicalizer.cpp

@@ -27,7 +27,8 @@ struct FoldingSetNodeIDBuilder {
     ID.AddString(llvm::StringRef(Str.begin(), Str.size()));
   }
   template <typename T>
-  std::enable_if_t<std::is_integral_v<T> || std::is_enum_v<T>> operator()(T V) {
+  std::enable_if_t<std::is_integral<T>::value || std::is_enum<T>::value>
+  operator()(T V) {
     ID.AddInteger((unsigned long long)V);
   }
   void operator()(itanium_demangle::NodeArray A) {

llvm/lib/Support/NativeFormatting.cpp

@@ -55,7 +55,7 @@ static void writeWithCommas(raw_ostream &S, ArrayRef<char> Buffer) {
 template <typename T>
 static void write_unsigned_impl(raw_ostream &S, T N, size_t MinDigits,
                                 IntegerStyle Style, bool IsNegative) {
-  static_assert(std::is_unsigned_v<T>, "Value is not unsigned!");
+  static_assert(std::is_unsigned<T>::value, "Value is not unsigned!");
 
   char NumberBuffer[128];
   std::memset(NumberBuffer, '0', sizeof(NumberBuffer));
@@ -92,7 +92,7 @@ static void write_unsigned(raw_ostream &S, T N, size_t MinDigits,
 template <typename T>
 static void write_signed(raw_ostream &S, T N, size_t MinDigits,
                          IntegerStyle Style) {
-  static_assert(std::is_signed_v<T>, "Value is not signed!");
+  static_assert(std::is_signed<T>::value, "Value is not signed!");
 
   using UnsignedT = std::make_unsigned_t<T>;
 

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -3574,8 +3574,8 @@ template <typename T>
 static bool hasCalleePopSRet(const SmallVectorImpl<T> &Args,
                              const X86Subtarget &Subtarget) {
   // Not C++20 (yet), so no concepts available.
-  static_assert(std::is_same_v<T, ISD::OutputArg> ||
-                    std::is_same_v<T, ISD::InputArg>,
+  static_assert(std::is_same<T, ISD::OutputArg>::value ||
+                    std::is_same<T, ISD::InputArg>::value,
                 "requires ISD::OutputArg or ISD::InputArg");
 
   // Only 32-bit pops the sret.  It's a 64-bit world these days, so early-out