Add _Float16 as a C/C++ source language type

This adds _Float16 as a source language type, which is a 16-bit floating point
type defined in C11 extension ISO/IEC TS 18661-3.

In follow up patches documentation and more tests will be added.

Differential Revision: https://reviews.llvm.org/D33719

llvm-svn: 312781

38 files changed, 578 insertions, 9 deletions

diff --git a/clang/include/clang-c/Index.h b/clang/include/clang-c/Index.h
index 3b5ea9fa539..0b0d160bf3a 100644
--- a/clang/include/clang-c/Index.h
+++ b/clang/include/clang-c/Index.h
@@ -3115,8 +3115,9 @@ enum CXTypeKind {
   CXType_ObjCSel = 29,
   CXType_Float128 = 30,
   CXType_Half = 31,
+  CXType_Float16 = 32,
   CXType_FirstBuiltin = CXType_Void,
-  CXType_LastBuiltin  = CXType_Half,
+  CXType_LastBuiltin  = CXType_Float16,
 
   CXType_Complex = 100,
   CXType_Pointer = 101,
diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index 3a511c98e35..acb0f657df0 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -973,6 +973,7 @@ public:
   CanQualType UnsignedLongLongTy, UnsignedInt128Ty;
   CanQualType FloatTy, DoubleTy, LongDoubleTy, Float128Ty;
   CanQualType HalfTy; // [OpenCL 6.1.1.1], ARM NEON
+  CanQualType Float16Ty; // C11 extension ISO/IEC TS 18661-3
   CanQualType FloatComplexTy, DoubleComplexTy, LongDoubleComplexTy;
   CanQualType Float128ComplexTy;
   CanQualType VoidPtrTy, NullPtrTy;
diff --git a/clang/include/clang/AST/BuiltinTypes.def b/clang/include/clang/AST/BuiltinTypes.def
index 181131aba07..e4f5f7db2f7 100644
--- a/clang/include/clang/AST/BuiltinTypes.def
+++ b/clang/include/clang/AST/BuiltinTypes.def
@@ -133,6 +133,9 @@ FLOATING_TYPE(Double, DoubleTy)
 // 'long double'
 FLOATING_TYPE(LongDouble, LongDoubleTy)
 
+// '_Float16'
+FLOATING_TYPE(Float16, HalfTy)
+
 // '__float128'
 FLOATING_TYPE(Float128, Float128Ty)
 
diff --git a/clang/include/clang/Basic/Specifiers.h b/clang/include/clang/Basic/Specifiers.h
index 50fb936e01d..377534baab0 100644
--- a/clang/include/clang/Basic/Specifiers.h
+++ b/clang/include/clang/Basic/Specifiers.h
@@ -52,6 +52,7 @@ namespace clang {
     TST_int,
     TST_int128,
     TST_half,         // OpenCL half, ARM NEON __fp16
+    TST_Float16,      // C11 extension ISO/IEC TS 18661-3
     TST_float,
     TST_double,
     TST_float128,
diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def
index 61c56877303..4f5e515657d 100644
--- a/clang/include/clang/Basic/TokenKinds.def
+++ b/clang/include/clang/Basic/TokenKinds.def
@@ -379,6 +379,9 @@ KEYWORD(co_yield                    , KEYCOROUTINES)
 MODULES_KEYWORD(module)
 MODULES_KEYWORD(import)
 
+// C11 Extension
+KEYWORD(_Float16                    , KEYALL)
+
 // GNU Extensions (in impl-reserved namespace)
 KEYWORD(_Decimal32                  , KEYALL)
 KEYWORD(_Decimal64                  , KEYALL)
diff --git a/clang/include/clang/Lex/LiteralSupport.h b/clang/include/clang/Lex/LiteralSupport.h
index b66581b428b..cc9223eb7db 100644
--- a/clang/include/clang/Lex/LiteralSupport.h
+++ b/clang/include/clang/Lex/LiteralSupport.h
@@ -65,6 +65,7 @@ public:
   bool isHalf : 1;          // 1.0h
   bool isFloat : 1;         // 1.0f
   bool isImaginary : 1;     // 1.0i
+  bool isFloat16 : 1;       // 1.0f16
   bool isFloat128 : 1;      // 1.0q
   uint8_t MicrosoftInteger; // Microsoft suffix extension i8, i16, i32, or i64.
 
diff --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index bc817150ab8..1d935df433f 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -280,6 +280,7 @@ public:
   static const TST TST_half = clang::TST_half;
   static const TST TST_float = clang::TST_float;
   static const TST TST_double = clang::TST_double;
+  static const TST TST_float16 = clang::TST_Float16;
   static const TST TST_float128 = clang::TST_float128;
   static const TST TST_bool = clang::TST_bool;
   static const TST TST_decimal32 = clang::TST_decimal32;
diff --git a/clang/include/clang/Serialization/ASTBitCodes.h b/clang/include/clang/Serialization/ASTBitCodes.h
index 9227b33d2c5..ab4b82e5d3f 100644
--- a/clang/include/clang/Serialization/ASTBitCodes.h
+++ b/clang/include/clang/Serialization/ASTBitCodes.h
@@ -826,6 +826,8 @@ namespace clang {
       PREDEF_TYPE_OMP_ARRAY_SECTION = 42,
       /// \brief The '__float128' type
       PREDEF_TYPE_FLOAT128_ID = 43,
+      /// \brief The '_Float16' type
+      PREDEF_TYPE_FLOAT16_ID = 44,
       /// \brief OpenCL image types with auto numeration
 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
       PREDEF_TYPE_##Id##_ID,
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index fbc8874e93e..4d26748b077 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -57,7 +57,7 @@ unsigned ASTContext::NumImplicitDestructors;
 unsigned ASTContext::NumImplicitDestructorsDeclared;
 
 enum FloatingRank {
-  HalfRank, FloatRank, DoubleRank, LongDoubleRank, Float128Rank
+  Float16Rank, HalfRank, FloatRank, DoubleRank, LongDoubleRank, Float128Rank
 };
 
 RawComment *ASTContext::getRawCommentForDeclNoCache(const Decl *D) const {
@@ -1093,6 +1093,9 @@ void ASTContext::InitBuiltinTypes(const TargetInfo &Target,
   // GNU extension, __float128 for IEEE quadruple precision
   InitBuiltinType(Float128Ty,          BuiltinType::Float128);
 
+  // C11 extension ISO/IEC TS 18661-3
+  InitBuiltinType(Float16Ty,           BuiltinType::Float16);
+
   // GNU extension, 128-bit integers.
   InitBuiltinType(Int128Ty,            BuiltinType::Int128);
   InitBuiltinType(UnsignedInt128Ty,    BuiltinType::UInt128);
@@ -1420,7 +1423,9 @@ const llvm::fltSemantics &ASTContext::getFloatTypeSemantics(QualType T) const {
   assert(BT && "Not a floating point type!");
   switch (BT->getKind()) {
   default: llvm_unreachable("Not a floating point type!");
-  case BuiltinType::Half:       return Target->getHalfFormat();
+  case BuiltinType::Float16:
+  case BuiltinType::Half:
+    return Target->getHalfFormat();
   case BuiltinType::Float:      return Target->getFloatFormat();
   case BuiltinType::Double:     return Target->getDoubleFormat();
   case BuiltinType::LongDouble: return Target->getLongDoubleFormat();
@@ -1748,6 +1753,7 @@ TypeInfo ASTContext::getTypeInfoImpl(const Type *T) const {
       Width = 128;
       Align = 128; // int128_t is 128-bit aligned on all targets.
       break;
+    case BuiltinType::Float16:
     case BuiltinType::Half:
       Width = Target->getHalfWidth();
       Align = Target->getHalfAlign();
@@ -5047,6 +5053,7 @@ static FloatingRank getFloatingRank(QualType T) {
   assert(T->getAs<BuiltinType>() && "getFloatingRank(): not a floating type");
   switch (T->getAs<BuiltinType>()->getKind()) {
   default: llvm_unreachable("getFloatingRank(): not a floating type");
+  case BuiltinType::Float16:    return Float16Rank;
   case BuiltinType::Half:       return HalfRank;
   case BuiltinType::Float:      return FloatRank;
   case BuiltinType::Double:     return DoubleRank;
@@ -5064,6 +5071,7 @@ QualType ASTContext::getFloatingTypeOfSizeWithinDomain(QualType Size,
   FloatingRank EltRank = getFloatingRank(Size);
   if (Domain->isComplexType()) {
     switch (EltRank) {
+    case Float16Rank:
     case HalfRank: llvm_unreachable("Complex half is not supported");
     case FloatRank:      return FloatComplexTy;
     case DoubleRank:     return DoubleComplexTy;
@@ -5074,6 +5082,7 @@ QualType ASTContext::getFloatingTypeOfSizeWithinDomain(QualType Size,
 
   assert(Domain->isRealFloatingType() && "Unknown domain!");
   switch (EltRank) {
+  case Float16Rank:    return HalfTy;
   case HalfRank:       return HalfTy;
   case FloatRank:      return FloatTy;
   case DoubleRank:     return DoubleTy;
@@ -5931,6 +5940,7 @@ static char getObjCEncodingForPrimitiveKind(const ASTContext *C,
     case BuiltinType::LongDouble: return 'D';
     case BuiltinType::NullPtr:    return '*'; // like char*
 
+    case BuiltinType::Float16:
     case BuiltinType::Float128:
     case BuiltinType::Half:
       // FIXME: potentially need @encodes for these!
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 1c90419ca97..95be23f26f1 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -2445,6 +2445,7 @@ void CXXNameMangler::mangleType(const BuiltinType *T) {
   // UNSUPPORTED:    ::= De # IEEE 754r decimal floating point (128 bits)
   // UNSUPPORTED:    ::= Df # IEEE 754r decimal floating point (32 bits)
   //                 ::= Dh # IEEE 754r half-precision floating point (16 bits)
+  //                 ::= DF <number> _ # ISO/IEC TS 18661 binary floating point type _FloatN (N bits);
   //                 ::= Di # char32_t
   //                 ::= Ds # char16_t
   //                 ::= Dn # std::nullptr_t (i.e., decltype(nullptr))
@@ -2507,6 +2508,9 @@ void CXXNameMangler::mangleType(const BuiltinType *T) {
   case BuiltinType::Int128:
     Out << 'n';
     break;
+  case BuiltinType::Float16:
+    Out << "DF16_";
+    break;
   case BuiltinType::Half:
     Out << "Dh";
     break;
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 5afaeef1eec..685dc62296f 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -1866,6 +1866,7 @@ void MicrosoftCXXNameMangler::mangleType(const BuiltinType *T, Qualifiers,
     Out << "$$T";
     break;
 
+  case BuiltinType::Float16:
   case BuiltinType::Float128:
   case BuiltinType::Half: {
     DiagnosticsEngine &Diags = Context.getDiags();
diff --git a/clang/lib/AST/NSAPI.cpp b/clang/lib/AST/NSAPI.cpp
index e7c8c16b014..8adaef1fb64 100644
--- a/clang/lib/AST/NSAPI.cpp
+++ b/clang/lib/AST/NSAPI.cpp
@@ -441,6 +441,7 @@ NSAPI::getNSNumberFactoryMethodKind(QualType T) const {
   case BuiltinType::Int128:
   case BuiltinType::LongDouble:
   case BuiltinType::UInt128:
+  case BuiltinType::Float16:
   case BuiltinType::Float128:
   case BuiltinType::NullPtr:
   case BuiltinType::ObjCClass:
diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index 950d0e29979..9cbd1ef7602 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -1500,6 +1500,7 @@ static void PrintFloatingLiteral(raw_ostream &OS, FloatingLiteral *Node,
   default: llvm_unreachable("Unexpected type for float literal!");
   case BuiltinType::Half:       break; // FIXME: suffix?
   case BuiltinType::Double:     break; // no suffix.
+  case BuiltinType::Float16:    OS << "F16"; break;
   case BuiltinType::Float:      OS << 'F'; break;
   case BuiltinType::LongDouble: OS << 'L'; break;
   case BuiltinType::Float128:   OS << 'Q'; break;
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 93510b244f1..8533cf24c3e 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -2564,6 +2564,8 @@ StringRef BuiltinType::getName(const PrintingPolicy &Policy) const {
     return "double";
   case LongDouble:
     return "long double";
+  case Float16:
+    return "_Float16";
   case Float128:
     return "__float128";
   case WChar_S:
diff --git a/clang/lib/AST/TypeLoc.cpp b/clang/lib/AST/TypeLoc.cpp
index c9a26865572..9ff437b4cc6 100644
--- a/clang/lib/AST/TypeLoc.cpp
+++ b/clang/lib/AST/TypeLoc.cpp
@@ -319,6 +319,7 @@ TypeSpecifierType BuiltinTypeLoc::getWrittenTypeSpec() const {
   case BuiltinType::Float:
   case BuiltinType::Double:
   case BuiltinType::LongDouble:
+  case BuiltinType::Float16:
   case BuiltinType::Float128:
     llvm_unreachable("Builtin type needs extra local data!");
     // Fall through, if the impossible happens.
diff --git a/clang/lib/Analysis/PrintfFormatString.cpp b/clang/lib/Analysis/PrintfFormatString.cpp
index 50a3aa20bd1..26636376d1e 100644
--- a/clang/lib/Analysis/PrintfFormatString.cpp
+++ b/clang/lib/Analysis/PrintfFormatString.cpp
@@ -654,6 +654,7 @@ bool PrintfSpecifier::fixType(QualType QT, const LangOptions &LangOpt,
   case BuiltinType::UInt128:
   case BuiltinType::Int128:
   case BuiltinType::Half:
+  case BuiltinType::Float16:
   case BuiltinType::Float128:
     // Various types which are non-trivial to correct.
     return false;
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 008f27c7a8f..befb704f39e 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -667,6 +667,7 @@ llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
   case BuiltinType::Half:
   case BuiltinType::Float:
   case BuiltinType::LongDouble:
+  case BuiltinType::Float16:
   case BuiltinType::Float128:
   case BuiltinType::Double:
     // FIXME: For targets where long double and __float128 have the same size,
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 46a01a3bb8b..1c95ba382dc 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1785,7 +1785,7 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
   }
 
   case CK_IntToOCLSampler:
-    return CGF.CGM.createOpenCLIntToSamplerConversion(E, CGF);

+    return CGF.CGM.createOpenCLIntToSamplerConversion(E, CGF);
 
   } // end of switch
 
diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index adc3b9b4c83..80f2a31ac00 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -443,6 +443,12 @@ llvm::Type *CodeGenTypes::ConvertType(QualType T) {
                                  static_cast<unsigned>(Context.getTypeSize(T)));
       break;
 
+    case BuiltinType::Float16:
+      ResultType =
+          getTypeForFormat(getLLVMContext(), Context.getFloatTypeSemantics(T),
+                           /* UseNativeHalf = */ true);
+      break;
+
     case BuiltinType::Half:
       // Half FP can either be storage-only (lowered to i16) or native.
       ResultType =
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index e07dbdd3abd..6e55a674183 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2665,6 +2665,7 @@ static bool TypeInfoIsInStandardLibrary(const BuiltinType *Ty) {
     case BuiltinType::Float:
     case BuiltinType::Double:
     case BuiltinType::LongDouble:
+    case BuiltinType::Float16:
     case BuiltinType::Float128:
     case BuiltinType::Char16:
     case BuiltinType::Char32:
diff --git a/clang/lib/Format/FormatToken.cpp b/clang/lib/Format/FormatToken.cpp
index ba5bf03a634..d1f16eb1c3c 100644
--- a/clang/lib/Format/FormatToken.cpp
+++ b/clang/lib/Format/FormatToken.cpp
@@ -52,6 +52,7 @@ bool FormatToken::isSimpleTypeSpecifier() const {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_wchar_t:
   case tok::kw_bool:
diff --git a/clang/lib/Index/USRGeneration.cpp b/clang/lib/Index/USRGeneration.cpp
index c4fe737e511..7afbb8bc365 100644
--- a/clang/lib/Index/USRGeneration.cpp
+++ b/clang/lib/Index/USRGeneration.cpp
@@ -680,6 +680,7 @@ void USRGenerator::VisitType(QualType T) {
           c = 'K'; break;
         case BuiltinType::Int128:
           c = 'J'; break;
+        case BuiltinType::Float16:
         case BuiltinType::Half:
           c = 'h'; break;
         case BuiltinType::Float:
diff --git a/clang/lib/Lex/LiteralSupport.cpp b/clang/lib/Lex/LiteralSupport.cpp
index f1738483f0a..5f6e5efa232 100644
--- a/clang/lib/Lex/LiteralSupport.cpp
+++ b/clang/lib/Lex/LiteralSupport.cpp
@@ -544,6 +544,7 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
   isHalf = false;
   isFloat = false;
   isImaginary = false;
+  isFloat16 = false;
   isFloat128 = false;
   MicrosoftInteger = 0;
   hadError = false;
@@ -588,6 +589,13 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
       if (!isFPConstant) break;  // Error for integer constant.
       if (isHalf || isFloat || isLong || isFloat128)
         break; // HF, FF, LF, QF invalid.
+
+      if (s + 2 < ThisTokEnd && s[1] == '1' && s[2] == '6') {
+          s += 2; // success, eat up 2 characters.
+          isFloat16 = true;
+          continue;
+      }
+
       isFloat = true;
       continue;  // Success.
     case 'q':    // FP Suffix for "__float128"
@@ -681,6 +689,7 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
         isUnsigned = false;
         isLongLong = false;
         isFloat = false;
+        isFloat16 = false;
         isHalf = false;
         isImaginary = false;
         MicrosoftInteger = 0;
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index b20b0db7d30..9ec78558d1a 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3510,6 +3510,10 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
       isInvalid = DS.SetTypeSpecType(DeclSpec::TST_double, Loc, PrevSpec,
                                      DiagID, Policy);
       break;
+    case tok::kw__Float16:
+      isInvalid = DS.SetTypeSpecType(DeclSpec::TST_float16, Loc, PrevSpec,
+                                     DiagID, Policy);
+      break;
     case tok::kw___float128:
       isInvalid = DS.SetTypeSpecType(DeclSpec::TST_float128, Loc, PrevSpec,
                                      DiagID, Policy);
@@ -4513,6 +4517,7 @@ bool Parser::isKnownToBeTypeSpecifier(const Token &Tok) const {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_bool:
   case tok::kw__Bool:
@@ -4588,6 +4593,7 @@ bool Parser::isTypeSpecifierQualifier() {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_bool:
   case tok::kw__Bool:
@@ -4744,6 +4750,7 @@ bool Parser::isDeclarationSpecifier(bool DisambiguatingWithExpression) {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_bool:
   case tok::kw__Bool:
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index b56231bb076..60985633409 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -1229,6 +1229,7 @@ ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_void:
   case tok::kw_typename:
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index 6ef747f402c..cfe03d7c4d1 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -1928,6 +1928,9 @@ void Parser::ParseCXXSimpleTypeSpecifier(DeclSpec &DS) {
   case tok::kw_double:
     DS.SetTypeSpecType(DeclSpec::TST_double, Loc, PrevSpec, DiagID, Policy);
     break;
+  case tok::kw__Float16:
+    DS.SetTypeSpecType(DeclSpec::TST_float16, Loc, PrevSpec, DiagID, Policy);
+    break;
   case tok::kw___float128:
     DS.SetTypeSpecType(DeclSpec::TST_float128, Loc, PrevSpec, DiagID, Policy);
     break;
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index d6684c39aa7..48393d9c004 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -1026,6 +1026,7 @@ Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
   case tok::kw_char:
   case tok::kw_const:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_enum:
   case tok::kw_half:
@@ -1510,6 +1511,7 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_void:
   case tok::annot_decltype:
@@ -1600,6 +1602,7 @@ bool Parser::isCXXDeclarationSpecifierAType() {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_void:
   case tok::kw___unknown_anytype:
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index e4e84fcec95..bce493989d2 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -336,6 +336,7 @@ bool Declarator::isDeclarationOfFunction() const {
     case TST_decimal32:
     case TST_decimal64:
     case TST_double:
+    case TST_Float16:
     case TST_float128:
     case TST_enum:
     case TST_error:
@@ -505,6 +506,7 @@ const char *DeclSpec::getSpecifierName(DeclSpec::TST T,
   case DeclSpec::TST_half:        return "half";
   case DeclSpec::TST_float:       return "float";
   case DeclSpec::TST_double:      return "double";
+  case DeclSpec::TST_float16:     return "_Float16";
   case DeclSpec::TST_float128:    return "__float128";
   case DeclSpec::TST_bool:        return Policy.Bool ? "bool" : "_Bool";
   case DeclSpec::TST_decimal32:   return "_Decimal32";
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 36317c0e7df..d551f63b5fb 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -132,6 +132,7 @@ bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw__Float16:
   case tok::kw___float128:
   case tok::kw_wchar_t:
   case tok::kw_bool:
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 1a644c88296..44b05e16580 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -714,8 +714,10 @@ ExprResult Sema::DefaultArgumentPromotion(Expr *E) {
     return ExprError();
   E = Res.get();
 
-  // If this is a 'float' or '__fp16' (CVR qualified or typedef) promote to
-  // double.
+  // If this is a 'float'  or '__fp16' (CVR qualified or typedef)
+  // promote to double.
+  // Note that default argument promotion applies only to float (and
+  // half/fp16); it does not apply to _Float16.
   const BuiltinType *BTy = Ty->getAs<BuiltinType>();
   if (BTy && (BTy->getKind() == BuiltinType::Half ||
               BTy->getKind() == BuiltinType::Float)) {
@@ -3321,6 +3323,8 @@ ExprResult Sema::ActOnNumericConstant(const Token &Tok, Scope *UDLScope) {
       Ty = Context.FloatTy;
     else if (Literal.isLong)
       Ty = Context.LongDoubleTy;
+    else if (Literal.isFloat16)
+      Ty = Context.Float16Ty;
     else if (Literal.isFloat128)
       Ty = Context.Float128Ty;
     else
diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index 14b8981f799..d81837dad50 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -819,6 +819,7 @@ bool Sema::containsUnexpandedParameterPacks(Declarator &D) {
   case TST_half:
   case TST_float:
   case TST_double:
+  case TST_Float16:
   case TST_float128:
   case TST_bool:
   case TST_decimal32:
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 598a11300b8..c4d7bb1f36a 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1392,8 +1392,9 @@ static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
     else
       Result = Context.Int128Ty;
     break;
-  case DeclSpec::TST_half: Result = Context.HalfTy; break;
-  case DeclSpec::TST_float: Result = Context.FloatTy; break;
+  case DeclSpec::TST_float16: Result = Context.Float16Ty; break;
+  case DeclSpec::TST_half:    Result = Context.HalfTy; break;
+  case DeclSpec::TST_float:   Result = Context.FloatTy; break;
   case DeclSpec::TST_double:
     if (DS.getTypeSpecWidth() == DeclSpec::TSW_long)
       Result = Context.LongDoubleTy;
diff --git a/clang/lib/Serialization/ASTCommon.cpp b/clang/lib/Serialization/ASTCommon.cpp
index 684ec243035..9c6f03cd0bb 100644
--- a/clang/lib/Serialization/ASTCommon.cpp
+++ b/clang/lib/Serialization/ASTCommon.cpp
@@ -91,6 +91,9 @@ serialization::TypeIdxFromBuiltin(const BuiltinType *BT) {
   case BuiltinType::LongDouble:
     ID = PREDEF_TYPE_LONGDOUBLE_ID;
     break;
+  case BuiltinType::Float16:
+    ID = PREDEF_TYPE_FLOAT16_ID;
+    break;
   case BuiltinType::Float128:
     ID = PREDEF_TYPE_FLOAT128_ID;
     break;
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 3221d78d167..3dba2997905 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -6683,6 +6683,9 @@ QualType ASTReader::GetType(TypeID ID) {
     case PREDEF_TYPE_LONGDOUBLE_ID:
       T = Context.LongDoubleTy;
       break;
+    case PREDEF_TYPE_FLOAT16_ID:
+      T = Context.Float16Ty;
+      break;
     case PREDEF_TYPE_FLOAT128_ID:
       T = Context.Float128Ty;
       break;
diff --git a/clang/test/CodeGenCXX/float16-declarations.cpp b/clang/test/CodeGenCXX/float16-declarations.cpp
new file mode 100644
index 00000000000..5007dff25ec
--- /dev/null
+++ b/clang/test/CodeGenCXX/float16-declarations.cpp
@@ -0,0 +1,156 @@
+// RUN: %clang -std=c++11 --target=aarch64-arm--eabi -S -emit-llvm %s -o - | FileCheck %s  --check-prefix=CHECK --check-prefix=CHECK-AARCH64
+// RUN: %clang -std=c++11 --target=x86_64 -S -emit-llvm %s -o - | FileCheck %s  --check-prefix=CHECK --check-prefix=CHECK-X86
+
+/*  Various contexts where type _Float16 can appear. */
+
+
+/*  Namespace */
+
+namespace {
+  _Float16 f1n;
+// CHECK-DAG: @_ZN12_GLOBAL__N_13f1nE = internal global half 0xH0000, align 2
+
+  _Float16 f2n = 33.f16;
+// CHECK-AARCH64-DAG: @_ZN12_GLOBAL__N_13f2nE = internal global half 0xH5020, align 2
+// CHECK-X86-DAG:     @_ZN12_GLOBAL__N_13f2nE = internal global i16 20512, align 2
+
+  _Float16 arr1n[10];
+// CHECK-AARCH64-DAG: @_ZN12_GLOBAL__N_15arr1nE = internal global [10 x half] zeroinitializer, align 2
+// CHECK-X86-DAG:     @_ZN12_GLOBAL__N_15arr1nE = internal global [10 x half] zeroinitializer, align 16
+
+  _Float16 arr2n[] = { 1.2, 3.0, 3.e4 };
+// CHECK-AARCH64-DAG: @_ZN12_GLOBAL__N_15arr2nE = internal global [3 x half] [half 0xH3CCD, half 0xH4200, half 0xH7753], align 2
+// CHECK-X86-DAG:     @_ZN12_GLOBAL__N_15arr2nE = internal global [3 x i16] [i16 15565, i16 16896, i16 30547], align 2
+
+  const volatile _Float16 func1n(const _Float16 &arg) {
+    return arg + f2n + arr1n[4] - arr2n[1];
+  }
+}
+
+
+/* File */
+
+_Float16 f1f;
+// CHECK-AARCH64-DAG: @f1f = global half 0xH0000, align 2
+// CHECK-X86-DAG: @f1f = global half 0xH0000, align 2
+
+_Float16 f2f = 32.4;
+// CHECK-AARCH64-DAG: @f2f = global half 0xH500D, align 2
+// CHECK-X86-DAG: @f2f = global i16 20493, align 2
+
+_Float16 arr1f[10];
+// CHECK-AARCH64-DAG: @arr1f = global [10 x half] zeroinitializer, align 2
+// CHECK-X86-DAG: @arr1f = global [10 x half] zeroinitializer, align 16
+
+_Float16 arr2f[] = { -1.2, -3.0, -3.e4 };
+// CHECK-AARCH64-DAG: @arr2f = global [3 x half] [half 0xHBCCD, half 0xHC200, half 0xHF753], align 2
+// CHECK-X86-DAG: @arr2f = global [3 x i16] [i16 -17203, i16 -15872, i16 -2221], align 2
+
+_Float16 func1f(_Float16 arg);
+
+
+/* Class */
+
+class C1 {
+  _Float16 f1c;
+
+  static const _Float16 f2c;
+// CHECK-DAG: @_ZN2C13f2cE = external constant half, align 2
+
+  volatile _Float16 f3c;
+
+public:
+  C1(_Float16 arg) : f1c(arg), f3c(arg) { }
+// Check that we mangle _Float16 to DF16_
+// CHECK-DAG: define linkonce_odr void @_ZN2C1C2EDF16_(%class.C1* %this, half %arg)
+
+  _Float16 func1c(_Float16 arg ) {
+    return f1c + arg;
+  }
+// CHECK-DAG: define linkonce_odr half @_ZN2C16func1cEDF16_(%class.C1* %this, half %arg)
+
+  static _Float16 func2c(_Float16 arg) {
+    return arg * C1::f2c;
+  }
+// CHECK-DAG: define linkonce_odr half @_ZN2C16func2cEDF16_(half %arg)
+};
+
+/*  Template */
+
+template <class C> C func1t(C arg) {
+  return arg * 2.f16;
+}
+// CHECK-DAG: define linkonce_odr half @_Z6func1tIDF16_ET_S0_(half %arg)
+
+template <class C> struct S1 {
+  C mem1;
+};
+
+template <> struct S1<_Float16> {
+  _Float16 mem2;
+};
+
+
+/* Local */
+
+extern int printf (const char *__restrict __format, ...);
+
+int main(void) {
+  _Float16 f1l = 1e3f16;
+// CHECK-DAG: store half 0xH63D0, half* %f1l, align 2
+
+  _Float16 f2l = -0.f16;
+// CHECK-DAG: store half 0xH8000, half* %f2l, align 2
+
+  _Float16 f3l = 1.000976562;
+// CHECK-DAG: store half 0xH3C01, half* %f3l, align 2
+
+  C1 c1(f1l);
+// CHECK-DAG:  [[F1L:%[a-z0-9]+]] = load half, half* %f1l, align 2
+// CHECK-DAG:  call void @_ZN2C1C2EDF16_(%class.C1* %c1, half [[F1L]])
+
+  S1<_Float16> s1 = { 132.f16 };
+// CHECK-AARCH64-DAG: @_ZZ4mainE2s1 = private unnamed_addr constant %struct.S1 { half 0xH5820 }, align 2
+// CHECK-X86-DAG:     @_ZZ4mainE2s1 = private unnamed_addr constant { i16 } { i16 22560 }, align 2
+// CHECK-DAG:  [[S1:%[0-9]+]] = bitcast %struct.S1* %s1 to i8*
+// CHECK-AARCH64-DAG: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[S1]], i8* bitcast (%struct.S1* @_ZZ4mainE2s1 to i8*), i64 2, i32 2, i1 false)
+// CHECK-X86-DAG:     call void @llvm.memcpy.p0i8.p0i8.i64(i8* %1, i8* bitcast ({ i16 }* @_ZZ4mainE2s1 to i8*), i64 2, i32 2, i1 false)
+
+  _Float16 f4l = func1n(f1l)  + func1f(f2l) + c1.func1c(f3l) + c1.func2c(f1l) +
+    func1t(f1l) + s1.mem2 - f1n + f2n;
+
+  auto f5l = -1.f16, *f6l = &f2l, f7l = func1t(f3l);
+// CHECK-DAG:  store half 0xHBC00, half* %f5l, align 2
+// CHECK-DAG:  store half* %f2l, half** %f6l, align 8
+
+  _Float16 f8l = f4l++;
+// CHECK-DAG:  [[F4L:%[a-z0-9]+]] = load half, half* %f4l, align 2
+// CHECK-DAG:  [[INC:%inc[0-9]*]] = fadd half [[F4L]], 0xH3C00
+// CHECK-DAG:  store half [[INC]], half* %f4l, align 2
+
+  _Float16 arr1l[] = { -1.f16, -0.f16, -11.f16 };
+// CHECK-AARCH64-DAG: @_ZZ4mainE5arr1l = private unnamed_addr constant [3 x half] [half 0xHBC00, half 0xH8000, half 0xHC980], align 2
+// CHECK-X86-DAG:     @_ZZ4mainE5arr1l = private unnamed_addr constant [3 x i16] [i16 -17408, i16 -32768, i16 -13952], align 2
+
+  float cvtf = f2n;
+//CHECK-DAG: [[H2F:%conv[0-9]*]] = fpext half {{%[0-9]+}} to float
+//CHECK-DAG:  store float [[H2F]], float* %cvtf, align 4
+
+  double cvtd = f2n;
+//CHECK-DAG: [[H2D:%conv[0-9]*]] = fpext half {{%[0-9]+}} to double
+//CHECK-DAG: store double [[H2D]], double* %cvtd, align 8
+
+
+  long double cvtld = f2n;
+//CHECK-AARCh64-DAG: [[H2LD:%conv[0-9]*]] = fpext half {{%[0-9]+}} to fp128
+//CHECK-AARCh64-DAG: store fp128 [[H2LD]], fp128* %cvtld, align 16
+//CHECK-X86-DAG:     [[H2LD:%conv[0-9]+]] = fpext half {{%[0-9]+}} to x86_fp80
+//CHECK-X86-DAG:     store x86_fp80 [[H2LD]], x86_fp80* %cvtld, align 16
+
+  _Float16 f2h = 42.0f;
+//CHECK-DAG: store half 0xH5140, half* %f2h, align 2
+  _Float16 d2h = 42.0;
+//CHECK-DAG: store half 0xH5140, half* %d2h, align 2
+  _Float16 ld2h = 42.0l;
+//CHECK-DAG:store half 0xH5140, half* %ld2h, align 2
+}
diff --git a/clang/test/Frontend/float16.cpp b/clang/test/Frontend/float16.cpp
new file mode 100644
index 00000000000..bd89d27ccb5
--- /dev/null
+++ b/clang/test/Frontend/float16.cpp
@@ -0,0 +1,326 @@
+// RUN: %clang_cc1 -std=c++11 -ast-dump %s | FileCheck %s --strict-whitespace
+// RUN: %clang_cc1 -std=c++11 -ast-dump -fnative-half-type %s | FileCheck %s --check-prefix=CHECK-NATIVE --strict-whitespace
+
+/*  Various contexts where type _Float16 can appear. */
+
+/*  Namespace */
+namespace {
+  _Float16 f1n;
+  _Float16 f2n = 33.f16;
+  _Float16 arr1n[10];
+  _Float16 arr2n[] = { 1.2, 3.0, 3.e4 };
+  const volatile _Float16 func1n(const _Float16 &arg) {
+    return arg + f2n + arr1n[4] - arr2n[1];
+  }
+}
+
+//CHECK:      |-NamespaceDecl
+//CHECK-NEXT: | |-VarDecl {{.*}} f1n '_Float16'
+//CHECK-NEXT: | |-VarDecl {{.*}} f2n '_Float16' cinit
+//CHECK-NEXT: | | `-FloatingLiteral {{.*}} '_Float16' 3.300000e+01
+//CHECK-NEXT: | |-VarDecl {{.*}} arr1n '_Float16 [10]'
+//CHECK-NEXT: | |-VarDecl {{.*}} arr2n '_Float16 [3]' cinit
+//CHECK-NEXT: | | `-InitListExpr {{.*}} '_Float16 [3]'
+//CHECK-NEXT: | |   |-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: | |   | `-FloatingLiteral {{.*}} 'double' 1.200000e+00
+//CHECK-NEXT: | |   |-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: | |   | `-FloatingLiteral {{.*}} 'double' 3.000000e+00
+//CHECK-NEXT: | |   `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: | |     `-FloatingLiteral {{.*}} 'double' 3.000000e+04
+//CHECK-NEXT: | `-FunctionDecl {{.*}} func1n 'const volatile _Float16 (const _Float16 &)'
+
+/* File */
+_Float16 f1f;
+_Float16 f2f = 32.4;
+_Float16 arr1f[10];
+_Float16 arr2f[] = { -1.2, -3.0, -3.e4 };
+_Float16 func1f(_Float16 arg);
+
+//CHECK:      |-VarDecl {{.*}} f1f '_Float16'
+//CHECK-NEXT: |-VarDecl {{.*}} f2f '_Float16' cinit
+//CHECK-NEXT: | `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: |   `-FloatingLiteral {{.*}} 'double' 3.240000e+01
+//CHECK-NEXT: |-VarDecl {{.*}} arr1f '_Float16 [10]'
+//CHECK-NEXT: |-VarDecl {{.*}} arr2f '_Float16 [3]' cinit
+//CHECK-NEXT: | `-InitListExpr {{.*}} '_Float16 [3]'
+//CHECK-NEXT: |   |-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: |   | `-UnaryOperator {{.*}} 'double' prefix '-'
+//CHECK-NEXT: |   |   `-FloatingLiteral {{.*}} 'double' 1.200000e+00
+//CHECK-NEXT: |   |-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: |   | `-UnaryOperator {{.*}} 'double' prefix '-'
+//CHECK-NEXT: |   |   `-FloatingLiteral {{.*}} 'double' 3.000000e+00
+//CHECK-NEXT: |   `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT: |     `-UnaryOperator {{.*}} 'double' prefix '-'
+//CHECK-NEXT: |       `-FloatingLiteral {{.*}} 'double' 3.000000e+04
+//CHECK-NEXT: |-FunctionDecl {{.*}} func1f '_Float16 (_Float16)'
+//CHECK-NEXT: | `-ParmVarDecl {{.*}} arg '_Float16'
+
+
+// Mixing __fp16 and Float16 types:
+// The _Float16 type is first converted to __fp16 type and then the operation
+// is completed as if both operands were of __fp16 type.
+
+__fp16 B = -0.1;
+auto C = -1.0f16 + B;
+
+// When we do *not* have native half types, we expect __fp16 to be promoted to
+// float, and consequently also _Float16 promotions to float:
+
+//CHECK:      -VarDecl {{.*}} used B '__fp16' cinit
+//CHECK-NEXT: | `-ImplicitCastExpr {{.*}} '__fp16' <FloatingCast>
+//CHECK-NEXT: |   `-UnaryOperator {{.*}} 'double' prefix '-'
+//CHECK-NEXT: |     `-FloatingLiteral {{.*}} 'double' 1.000000e-01
+//CHECK-NEXT: |-VarDecl {{.*}} C 'float':'float' cinit
+//CHECK-NEXT: | `-BinaryOperator {{.*}} 'float' '+'
+//CHECK-NEXT: |   |-ImplicitCastExpr {{.*}} 'float' <FloatingCast>
+//CHECK-NEXT: |   | `-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NEXT: |   |   `-FloatingLiteral {{.*}} '_Float16' 1.000000e+00
+//CHECK-NEXT: |   `-ImplicitCastExpr {{.*}} 'float' <FloatingCast>
+//CHECK-NEXT: |     `-ImplicitCastExpr {{.*}} '__fp16' <LValueToRValue>
+//CHECK-NEXT: |       `-DeclRefExpr {{.*}} '__fp16' lvalue Var 0x{{.*}} 'B' '__fp16'
+
+// When do have native half types, we expect to see promotions to fp16:
+
+//CHECK-NATIVE: |-VarDecl {{.*}} used B '__fp16' cinit
+//CHECK-NATIVE: | `-ImplicitCastExpr {{.*}} '__fp16' <FloatingCast>
+//CHECK-NATIVE: |   `-UnaryOperator {{.*}} 'double' prefix '-'
+//CHECK-NATIVE: |     `-FloatingLiteral {{.*}} 'double' 1.000000e-01
+//CHECK-NATIVE: |-VarDecl {{.*}} C '__fp16':'__fp16' cinit
+//CHECK-NATIVE: | `-BinaryOperator {{.*}} '__fp16' '+'
+//CHECK-NATIVE: |   |-ImplicitCastExpr {{.*}} '__fp16' <FloatingCast>
+//CHECK-NATIVE: |   | `-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NATIVE: |   |   `-FloatingLiteral {{.*}} '_Float16' 1.000000e+00
+//CHECK-NATIVE: |   `-ImplicitCastExpr {{.*}} '__fp16' <LValueToRValue>
+//CHECK-NATIVE: |     `-DeclRefExpr {{.*}} '__fp16' lvalue Var 0x{{.*}} 'B' '__fp16'
+
+
+/* Class */
+
+class C1 {
+  _Float16 f1c;
+  static const _Float16 f2c;
+  volatile _Float16 f3c;
+public:
+  C1(_Float16 arg) : f1c(arg), f3c(arg) { }
+  _Float16 func1c(_Float16 arg ) {
+    return f1c + arg;
+  }
+  static _Float16 func2c(_Float16 arg) {
+    return arg * C1::f2c;
+  }
+};
+
+//CHECK:      |-CXXRecordDecl {{.*}} referenced class C1 definition
+//CHECK-NEXT: | |-CXXRecordDecl {{.*}} implicit referenced class C1
+//CHECK-NEXT: | |-FieldDecl {{.*}} referenced f1c '_Float16'
+//CHECK-NEXT: | |-VarDecl {{.*}} used f2c 'const _Float16' static
+//CHECK-NEXT: | |-FieldDecl {{.*}} f3c 'volatile _Float16'
+//CHECK-NEXT: | |-AccessSpecDecl
+//CHECK-NEXT: | |-CXXConstructorDecl {{.*}} used C1 'void (_Float16)'
+//CHECK-NEXT: | | |-ParmVarDecl {{.*}} used arg '_Float16'
+//CHECK-NEXT: | | |-CXXCtorInitializer Field {{.*}} 'f1c' '_Float16'
+//CHECK-NEXT: | | | `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT: | | |   `-DeclRefExpr {{.*}} '_Float16' lvalue ParmVar 0x{{.*}} 'arg' '_Float16'
+//CHECK-NEXT: | | |-CXXCtorInitializer Field {{.*}} 'f3c' 'volatile _Float16'
+//CHECK-NEXT: | | | `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT: | | |   `-DeclRefExpr {{.*}} '_Float16' lvalue ParmVar 0x{{.*}} 'arg' '_Float16'
+//CHECK-NEXT: | | `-CompoundStmt
+//CHECK-NEXT: | |-CXXMethodDecl {{.*}} used func1c '_Float16 (_Float16)'
+//CHECK-NEXT: | | |-ParmVarDecl {{.*}} used arg '_Float16'
+//CHECK-NEXT: | | `-CompoundStmt
+//CHECK-NEXT: | |   `-ReturnStmt
+//CHECK-NEXT: | |     `-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT: | |       |-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT: | |       | `-MemberExpr {{.*}} '_Float16' lvalue ->f1c 0x{{.*}}
+//CHECK-NEXT: | |       |   `-CXXThisExpr {{.*}} 'class C1 *' this
+//CHECK-NEXT: | |       `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT: | |         `-DeclRefExpr {{.*}} '_Float16' lvalue ParmVar 0x{{.*}} 'arg' '_Float16'
+//CHECK-NEXT: | |-CXXMethodDecl {{.*}} used func2c '_Float16 (_Float16)' static
+//CHECK-NEXT: | | |-ParmVarDecl {{.*}} used arg '_Float16'
+//CHECK-NEXT: | | `-CompoundStmt
+//CHECK-NEXT: | |   `-ReturnStmt
+//CHECK-NEXT: | |     `-BinaryOperator {{.*}} '_Float16' '*'
+//CHECK-NEXT: | |       |-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT: | |       | `-DeclRefExpr {{.*}} '_Float16' lvalue ParmVar 0x{{.*}} 'arg' '_Float16'
+//CHECK-NEXT: | |       `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT: | |         `-DeclRefExpr {{.*}} 'const _Float16' lvalue Var 0x{{.*}} 'f2c' 'const _Float16'
+
+
+/*  Template */
+
+template <class C> C func1t(C arg) {
+  return arg * 2.f16;
+}
+
+//CHECK:      |-FunctionTemplateDecl {{.*}} func1t
+//CHECK-NEXT: | |-TemplateTypeParmDecl {{.*}} C
+//CHECK-NEXT: | |-FunctionDecl {{.*}} func1t 'C (C)'
+//CHECK-NEXT: | | |-ParmVarDecl {{.*}} referenced arg 'C'
+//CHECK-NEXT: | | `-CompoundStmt
+//CHECK-NEXT: | |   `-ReturnStmt
+//CHECK-NEXT: | |     `-BinaryOperator {{.*}} '<dependent type>' '*'
+//CHECK-NEXT: | |       |-DeclRefExpr {{.*}} 'C' lvalue ParmVar {{.*}} 'arg' 'C'
+//CHECK-NEXT: | |       `-FloatingLiteral {{.*}} '_Float16' 2.000000e+00
+//CHECK-NEXT: | `-FunctionDecl {{.*}} used func1t '_Float16 (_Float16)'
+//CHECK-NEXT: |   |-TemplateArgument type '_Float16'
+//CHECK-NEXT: |   |-ParmVarDecl {{.*}} used arg '_Float16':'_Float16'
+//CHECK-NEXT: |   `-CompoundStmt
+//CHECK-NEXT: |     `-ReturnStmt
+//CHECK-NEXT: |       `-BinaryOperator {{.*}} '_Float16' '*'
+//CHECK-NEXT: |         |-ImplicitCastExpr {{.*}} '_Float16':'_Float16' <LValueToRValue>
+//CHECK-NEXT: |         | `-DeclRefExpr {{.*}} '_Float16':'_Float16' lvalue ParmVar {{.*}} 'arg' '_Float16':'_Float16'
+//CHECK-NEXT: |         `-FloatingLiteral {{.*}} '_Float16' 2.000000e+00
+
+
+template <class C> struct S1 {
+  C mem1;
+};
+
+//CHECK:      |-ClassTemplateDecl {{.*}} S1
+//CHECK-NEXT: | |-TemplateTypeParmDecl {{.*}} referenced class depth 0 index 0 C
+//CHECK-NEXT: | |-CXXRecordDecl {{.*}} struct S1 definition
+//CHECK-NEXT: | | |-CXXRecordDecl {{.*}} implicit struct S1
+//CHECK-NEXT: | | `-FieldDecl {{.*}} mem1 'C'
+//CHECK-NEXT: | `-ClassTemplateSpecialization {{.*}} 'S1'
+
+template <> struct S1<_Float16> {
+  _Float16 mem2;
+};
+
+
+/* Local */
+
+extern int printf (const char *__restrict __format, ...);
+
+int main(void) {
+  _Float16 f1l = 1e3f16;
+//CHECK:       | `-VarDecl {{.*}} used f1l '_Float16' cinit
+//CHECK-NEXT:  |   `-FloatingLiteral {{.*}} '_Float16' 1.000000e+03
+
+  _Float16 f2l = -0.f16;
+//CHECK:       | `-VarDecl {{.*}} used f2l '_Float16' cinit
+//CHECK-NEXT:  |   `-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NEXT:  |     `-FloatingLiteral {{.*}} '_Float16' 0.000000e+00
+
+  _Float16 f3l = 1.000976562;
+//CHECK:       | `-VarDecl {{.*}} used f3l '_Float16' cinit
+//CHECK-NEXT:  |   `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT:  |     `-FloatingLiteral {{.*}} 'double' 1.000977e+00
+
+  C1 c1(f1l);
+//CHECK:       | `-VarDecl{{.*}} used c1 'class C1' callinit
+//CHECK-NEXT:  |   `-CXXConstructExpr {{.*}} 'class C1' 'void (_Float16)'
+//CHECK-NEXT:  |     `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |       `-DeclRefExpr {{.*}} '_Float16' lvalue Var 0x{{.*}} 'f1l' '_Float16'
+
+  S1<_Float16> s1 = { 132.f16 };
+//CHECK:       | `-VarDecl {{.*}} used s1 'S1<_Float16>':'struct S1<_Float16>' cinit
+//CHECK-NEXT:  |   `-InitListExpr {{.*}} 'S1<_Float16>':'struct S1<_Float16>'
+//CHECK-NEXT:  |     `-FloatingLiteral {{.*}} '_Float16' 1.320000e+02
+
+  _Float16 f4l = func1n(f1l)  + func1f(f2l) + c1.func1c(f3l) + c1.func2c(f1l) +
+    func1t(f1l) + s1.mem2 - f1n + f2n;
+//CHECK:       | `-VarDecl {{.*}} used f4l '_Float16' cinit
+//CHECK-NEXT:  |   `-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT:  |     |-BinaryOperator {{.*}} '_Float16' '-'
+//CHECK-NEXT:  |     | |-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT:  |     | | |-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT:  |     | | | |-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT:  |     | | | | |-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT:  |     | | | | | |-BinaryOperator {{.*}} '_Float16' '+'
+//CHECK-NEXT:  |     | | | | | | |-CallExpr {{.*}} '_Float16'
+//CHECK-NEXT:  |     | | | | | | | |-ImplicitCastExpr {{.*}} 'const volatile _Float16 (*)(const _Float16 &)' <FunctionToPointerDecay>
+//CHECK-NEXT:  |     | | | | | | | | `-DeclRefExpr {{.*}} 'const volatile _Float16 (const _Float16 &)' lvalue Function {{.*}} 'func1n' 'const volatile _Float16 (const _Float16 &)'
+//CHECK-NEXT:  |     | | | | | | | `-ImplicitCastExpr {{.*}} 'const _Float16' lvalue <NoOp>
+//CHECK-NEXT:  |     | | | | | | |   `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f1l' '_Float16'
+//CHECK-NEXT:  |     | | | | | | `-CallExpr {{.*}} '_Float16'
+//CHECK-NEXT:  |     | | | | | |   |-ImplicitCastExpr {{.*}} '_Float16 (*)(_Float16)' <FunctionToPointerDecay>
+//CHECK-NEXT:  |     | | | | | |   | `-DeclRefExpr {{.*}} '_Float16 (_Float16)' lvalue Function {{.*}} 'func1f' '_Float16 (_Float16)'
+//CHECK-NEXT:  |     | | | | | |   `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |     | | | | | |     `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f2l' '_Float16'
+//CHECK-NEXT:  |     | | | | | `-CXXMemberCallExpr {{.*}} '_Float16'
+//CHECK-NEXT:  |     | | | | |   |-MemberExpr {{.*}} '<bound member function type>' .func1c {{.*}}
+//CHECK-NEXT:  |     | | | | |   | `-DeclRefExpr {{.*}} 'class C1' lvalue Var {{.*}} 'c1' 'class C1'
+//CHECK-NEXT:  |     | | | | |   `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |     | | | | |     `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f3l' '_Float16'
+//CHECK-NEXT:  |     | | | | `-CallExpr {{.*}} '_Float16'
+//CHECK-NEXT:  |     | | | |   |-ImplicitCastExpr {{.*}} '_Float16 (*)(_Float16)' <FunctionToPointerDecay>
+//CHECK-NEXT:  |     | | | |   | `-MemberExpr {{.*}} '_Float16 (_Float16)' lvalue .func2c {{.*}}
+//CHECK-NEXT:  |     | | | |   |   `-DeclRefExpr {{.*}} 'class C1' lvalue Var {{.*}} 'c1' 'class C1'
+//CHECK-NEXT:  |     | | | |   `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |     | | | |     `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f1l' '_Float16'
+//CHECK-NEXT:  |     | | | `-CallExpr {{.*}} '_Float16':'_Float16'
+//CHECK-NEXT:  |     | | |   |-ImplicitCastExpr {{.*}} '_Float16 (*)(_Float16)' <FunctionToPointerDecay>
+//CHECK-NEXT:  |     | | |   | `-DeclRefExpr {{.*}} '_Float16 (_Float16)' lvalue Function {{.*}} 'func1t' '_Float16 (_Float16)' (FunctionTemplate {{.*}} 'func1t')
+//CHECK-NEXT:  |     | | |   `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |     | | |     `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f1l' '_Float16'
+//CHECK-NEXT:  |     | | `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |     | |   `-MemberExpr {{.*}} '_Float16' lvalue .mem2 {{.*}}
+//CHECK-NEXT:  |     | |     `-DeclRefExpr {{.*}} 'S1<_Float16>':'struct S1<_Float16>' lvalue Var {{.*}} 's1' 'S1<_Float16>':'struct S1<_Float16>'
+//CHECK-NEXT:  |     | `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |     |   `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f1n' '_Float16'
+//CHECK-NEXT:  |     `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |       `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f2n' '_Float16'
+
+  auto f5l = -1.f16, *f6l = &f2l, f7l = func1t(f3l);
+//CHECK:       | |-VarDecl {{.*}} f5l '_Float16':'_Float16' cinit
+//CHECK-NEXT:  | | `-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NEXT:  | |   `-FloatingLiteral {{.*}} '_Float16' 1.000000e+00
+//CHECK-NEXT:  | |-VarDecl {{.*}} f6l '_Float16 *' cinit
+//CHECK-NEXT:  | | `-UnaryOperator {{.*}} '_Float16 *' prefix '&'
+//CHECK-NEXT:  | |   `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f2l' '_Float16'
+//CHECK-NEXT:  | `-VarDecl {{.*}} f7l '_Float16':'_Float16' cinit
+//CHECK-NEXT:  |   `-CallExpr {{.*}} '_Float16':'_Float16'
+//CHECK-NEXT:  |     |-ImplicitCastExpr {{.*}} '_Float16 (*)(_Float16)' <FunctionToPointerDecay>
+//CHECK-NEXT:  |     | `-DeclRefExpr {{.*}} '_Float16 (_Float16)' lvalue Function {{.*}} 'func1t' '_Float16 (_Float16)' (FunctionTemplate {{.*}} 'func1t')
+//CHECK-NEXT:  |     `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:  |       `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f3l' '_Float16'
+
+  _Float16 f8l = f4l++;
+//CHECK:       | `-VarDecl {{.*}} f8l '_Float16' cinit
+//CHECK-NEXT:  |   `-UnaryOperator {{.*}} '_Float16' postfix '++'
+//CHECK-NEXT:  |     `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f4l' '_Float16'
+
+  _Float16 arr1l[] = { -1.f16, -0.f16, -11.f16 };
+//CHECK:       `-VarDecl {{.*}} arr1l '_Float16 [3]' cinit
+//CHECK-NEXT:    `-InitListExpr {{.*}} '_Float16 [3]'
+//CHECK-NEXT:      |-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NEXT:      | `-FloatingLiteral {{.*}} '_Float16' 1.000000e+00
+//CHECK-NEXT:      |-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NEXT:      | `-FloatingLiteral {{.*}} '_Float16' 0.000000e+00
+//CHECK-NEXT:      `-UnaryOperator {{.*}} '_Float16' prefix '-'
+//CHECK-NEXT:        `-FloatingLiteral {{.*}} '_Float16' 1.100000e+01
+
+  float cvtf = f2n;
+//CHECK:       `-VarDecl {{.*}} cvtf 'float' cinit
+//CHECK-NEXT:    `-ImplicitCastExpr {{.*}} 'float' <FloatingCast>
+//CHECK-NEXT:      `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:        `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f2n' '_Float16'
+
+  double cvtd = f2n;
+//CHECK:       `-VarDecl {{.*}} cvtd 'double' cinit
+//CHECK-NEXT:    `-ImplicitCastExpr {{.*}} 'double' <FloatingCast>
+//CHECK-NEXT:      `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:        `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f2n' '_Float16'
+
+  long double cvtld = f2n;
+//CHECK:       `-VarDecl {{.*}} cvtld 'long double' cinit
+//CHECK-NEXT:    `-ImplicitCastExpr {{.*}} 'long double' <FloatingCast>
+//CHECK-NEXT:      `-ImplicitCastExpr {{.*}} '_Float16' <LValueToRValue>
+//CHECK-NEXT:        `-DeclRefExpr {{.*}} '_Float16' lvalue Var {{.*}} 'f2n' '_Float16'
+
+  _Float16 f2h = 42.0f;
+//CHECK:       `-VarDecl {{.*}} f2h '_Float16' cinit
+//CHECK-NEXT:    `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT:      `-FloatingLiteral {{.*}} 'float' 4.200000e+01
+
+  _Float16 d2h = 42.0;
+//CHECK:       `-VarDecl {{.*}} d2h '_Float16' cinit
+//CHECK-NEXT:    `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT:      `-FloatingLiteral {{.*}} 'double' 4.200000e+01
+
+  _Float16 ld2h = 42.0l;
+//CHECK:       `-VarDecl {{.*}} ld2h '_Float16' cinit
+//CHECK-NEXT:    `-ImplicitCastExpr {{.*}} '_Float16' <FloatingCast>
+//CHECK-NEXT:      `-FloatingLiteral {{.*}} 'long double' 4.200000e+01
+}
diff --git a/clang/test/Lexer/half-literal.cpp b/clang/test/Lexer/half-literal.cpp
index 32af3faef9a..b87eae4a152 100644
--- a/clang/test/Lexer/half-literal.cpp
+++ b/clang/test/Lexer/half-literal.cpp
@@ -1,3 +1,6 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -pedantic %s
 float a = 1.0h; // expected-error{{invalid suffix 'h' on floating constant}}
 float b = 1.0H; // expected-error{{invalid suffix 'H' on floating constant}}
+
+_Float16 c = 1.f166; // expected-error{{invalid suffix 'f166' on floating constant}}
+_Float16 d = 1.f1;   // expected-error{{invalid suffix 'f1' on floating constant}}
diff --git a/clang/tools/libclang/CXType.cpp b/clang/tools/libclang/CXType.cpp
index d2cb5090591..6ad506aa491 100644
--- a/clang/tools/libclang/CXType.cpp
+++ b/clang/tools/libclang/CXType.cpp
@@ -53,6 +53,7 @@ static CXTypeKind GetBuiltinTypeKind(const BuiltinType *BT) {
     BTCASE(Float);
     BTCASE(Double);
     BTCASE(LongDouble);
+    BTCASE(Float16);
     BTCASE(Float128);
     BTCASE(NullPtr);
     BTCASE(Overload);
@@ -520,7 +521,7 @@ CXString clang_getTypeKindSpelling(enum CXTypeKind K) {
     TKIND(Char_U);
     TKIND(UChar);
     TKIND(Char16);
-    TKIND(Char32);  
+    TKIND(Char32);
     TKIND(UShort);
     TKIND(UInt);
     TKIND(ULong);
@@ -538,6 +539,7 @@ CXString clang_getTypeKindSpelling(enum CXTypeKind K) {
     TKIND(Float);
     TKIND(Double);
     TKIND(LongDouble);
+    TKIND(Float16);
     TKIND(Float128);
     TKIND(NullPtr);
     TKIND(Overload);