Enable support for __float128 in Clang

This patch corresponds to review:
http://reviews.llvm.org/D15120

It adds support for the __float128 keyword, literals and a target feature to
enable it. This support is disabled by default on all targets and any target
that has support for this type is free to add it.

Based on feedback that I've received from target maintainers, this appears to
be the right thing for most targets. I have not heard from the maintainers of
X86 which I believe supports this type. I will subsequently investigate the
impact of enabling this on X86.

llvm-svn: 266186

31 files changed, 218 insertions, 52 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index fb4c80bd7fd..2b103308bb2 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -58,7 +58,7 @@ unsigned ASTContext::NumImplicitDestructors;
 unsigned ASTContext::NumImplicitDestructorsDeclared;
 
 enum FloatingRank {
-  HalfRank, FloatRank, DoubleRank, LongDoubleRank
+  HalfRank, FloatRank, DoubleRank, LongDoubleRank, Float128Rank
 };
 
 RawComment *ASTContext::getRawCommentForDeclNoCache(const Decl *D) const {
@@ -967,14 +967,6 @@ TypedefDecl *ASTContext::getUInt128Decl() const {
   return UInt128Decl;
 }
 
-TypeDecl *ASTContext::getFloat128StubType() const {
-  assert(LangOpts.CPlusPlus && "should only be called for c++");
-  if (!Float128StubDecl)
-    Float128StubDecl = buildImplicitRecord("__float128");
-
-  return Float128StubDecl;
-}
-
 void ASTContext::InitBuiltinType(CanQualType &R, BuiltinType::Kind K) {
   BuiltinType *Ty = new (*this, TypeAlignment) BuiltinType(K);
   R = CanQualType::CreateUnsafe(QualType(Ty, 0));
@@ -1023,6 +1015,9 @@ void ASTContext::InitBuiltinTypes(const TargetInfo &Target,
   InitBuiltinType(DoubleTy,            BuiltinType::Double);
   InitBuiltinType(LongDoubleTy,        BuiltinType::LongDouble);
 
+  // GNU extension, __float128 for IEEE quadruple precision
+  InitBuiltinType(Float128Ty,          BuiltinType::Float128);
+
   // GNU extension, 128-bit integers.
   InitBuiltinType(Int128Ty,            BuiltinType::Int128);
   InitBuiltinType(UnsignedInt128Ty,    BuiltinType::UInt128);
@@ -1084,6 +1079,7 @@ void ASTContext::InitBuiltinTypes(const TargetInfo &Target,
   FloatComplexTy      = getComplexType(FloatTy);
   DoubleComplexTy     = getComplexType(DoubleTy);
   LongDoubleComplexTy = getComplexType(LongDoubleTy);
+  Float128ComplexTy   = getComplexType(Float128Ty);
 
   // Builtin types for 'id', 'Class', and 'SEL'.
   InitBuiltinType(ObjCBuiltinIdTy, BuiltinType::ObjCId);
@@ -1341,6 +1337,7 @@ const llvm::fltSemantics &ASTContext::getFloatTypeSemantics(QualType T) const {
   case BuiltinType::Float:      return Target->getFloatFormat();
   case BuiltinType::Double:     return Target->getDoubleFormat();
   case BuiltinType::LongDouble: return Target->getLongDoubleFormat();
+  case BuiltinType::Float128:   return Target->getFloat128Format();
   }
 }
 
@@ -1651,6 +1648,10 @@ TypeInfo ASTContext::getTypeInfoImpl(const Type *T) const {
       Width = Target->getLongDoubleWidth();
       Align = Target->getLongDoubleAlign();
       break;
+    case BuiltinType::Float128:
+      Width = Target->getFloat128Width();
+      Align = Target->getFloat128Align();
+      break;
     case BuiltinType::NullPtr:
       Width = Target->getPointerWidth(0); // C++ 3.9.1p11: sizeof(nullptr_t)
       Align = Target->getPointerAlign(0); //   == sizeof(void*)
@@ -4635,6 +4636,7 @@ static FloatingRank getFloatingRank(QualType T) {
   case BuiltinType::Float:      return FloatRank;
   case BuiltinType::Double:     return DoubleRank;
   case BuiltinType::LongDouble: return LongDoubleRank;
+  case BuiltinType::Float128:   return Float128Rank;
   }
 }
 
@@ -4651,6 +4653,7 @@ QualType ASTContext::getFloatingTypeOfSizeWithinDomain(QualType Size,
     case FloatRank:      return FloatComplexTy;
     case DoubleRank:     return DoubleComplexTy;
     case LongDoubleRank: return LongDoubleComplexTy;
+    case Float128Rank:   return Float128ComplexTy;
     }
   }
 
@@ -4660,6 +4663,7 @@ QualType ASTContext::getFloatingTypeOfSizeWithinDomain(QualType Size,
   case FloatRank:      return FloatTy;
   case DoubleRank:     return DoubleTy;
   case LongDoubleRank: return LongDoubleTy;
+  case Float128Rank:   return Float128Ty;
   }
   llvm_unreachable("getFloatingRank(): illegal value for rank");
 }
@@ -5489,6 +5493,7 @@ static char getObjCEncodingForPrimitiveKind(const ASTContext *C,
     case BuiltinType::LongDouble: return 'D';
     case BuiltinType::NullPtr:    return '*'; // like char*
 
+    case BuiltinType::Float128:
     case BuiltinType::Half:
       // FIXME: potentially need @encodes for these!
       return ' ';
@@ -8679,6 +8684,8 @@ QualType ASTContext::getRealTypeForBitwidth(unsigned DestWidth) const {
     return DoubleTy;
   case TargetInfo::LongDouble:
     return LongDoubleTy;
+  case TargetInfo::Float128:
+    return Float128Ty;
   case TargetInfo::NoFloat:
     return QualType();
   }
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 7ad464e1d91..67f5a57263a 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -1992,7 +1992,7 @@ void CXXNameMangler::mangleType(const BuiltinType *T) {
   //                 ::= f  # float
   //                 ::= d  # double
   //                 ::= e  # long double, __float80
-  // UNSUPPORTED:    ::= g  # __float128
+  //                 ::= g  # __float128
   // UNSUPPORTED:    ::= Dd # IEEE 754r decimal floating point (64 bits)
   // UNSUPPORTED:    ::= De # IEEE 754r decimal floating point (128 bits)
   // UNSUPPORTED:    ::= Df # IEEE 754r decimal floating point (32 bits)
@@ -2073,6 +2073,12 @@ void CXXNameMangler::mangleType(const BuiltinType *T) {
                 ? 'g'
                 : 'e');
     break;
+  case BuiltinType::Float128:
+    if (getASTContext().getTargetInfo().useFloat128ManglingForLongDouble())
+      Out << "U10__float128"; // Match the GCC mangling
+    else
+      Out << 'g';
+    break;
   case BuiltinType::NullPtr:
     Out << "Dn";
     break;
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index b63b5e5651e..c9caddbb6fc 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -1751,6 +1751,7 @@ void MicrosoftCXXNameMangler::mangleType(const BuiltinType *T, Qualifiers,
     Out << "$$T";
     break;
 
+  case BuiltinType::Float128:
   case BuiltinType::Half: {
     DiagnosticsEngine &Diags = Context.getDiags();
     unsigned DiagID = Diags.getCustomDiagID(
diff --git a/clang/lib/AST/NSAPI.cpp b/clang/lib/AST/NSAPI.cpp
index 4c49e4c9f6c..ac2a8d35424 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::Float128:
   case BuiltinType::NullPtr:
   case BuiltinType::ObjCClass:
   case BuiltinType::ObjCId:
diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index cc383740926..0b3f9087909 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -1310,6 +1310,7 @@ static void PrintFloatingLiteral(raw_ostream &OS, FloatingLiteral *Node,
   case BuiltinType::Double:     break; // no suffix.
   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 1c6ae2a2b9c..0262f5ba4a3 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -1777,7 +1777,7 @@ bool Type::hasUnsignedIntegerRepresentation() const {
 bool Type::isFloatingType() const {
   if (const BuiltinType *BT = dyn_cast<BuiltinType>(CanonicalType))
     return BT->getKind() >= BuiltinType::Half &&
-           BT->getKind() <= BuiltinType::LongDouble;
+           BT->getKind() <= BuiltinType::Float128;
   if (const ComplexType *CT = dyn_cast<ComplexType>(CanonicalType))
     return CT->getElementType()->isFloatingType();
   return false;
@@ -1799,7 +1799,7 @@ bool Type::isRealFloatingType() const {
 bool Type::isRealType() const {
   if (const BuiltinType *BT = dyn_cast<BuiltinType>(CanonicalType))
     return BT->getKind() >= BuiltinType::Bool &&
-           BT->getKind() <= BuiltinType::LongDouble;
+           BT->getKind() <= BuiltinType::Float128;
   if (const EnumType *ET = dyn_cast<EnumType>(CanonicalType))
       return ET->getDecl()->isComplete() && !ET->getDecl()->isScoped();
   return false;
@@ -1808,7 +1808,7 @@ bool Type::isRealType() const {
 bool Type::isArithmeticType() const {
   if (const BuiltinType *BT = dyn_cast<BuiltinType>(CanonicalType))
     return BT->getKind() >= BuiltinType::Bool &&
-           BT->getKind() <= BuiltinType::LongDouble;
+           BT->getKind() <= BuiltinType::Float128;
   if (const EnumType *ET = dyn_cast<EnumType>(CanonicalType))
     // GCC allows forward declaration of enum types (forbid by C99 6.7.2.3p2).
     // If a body isn't seen by the time we get here, return false.
@@ -2552,6 +2552,8 @@ StringRef BuiltinType::getName(const PrintingPolicy &Policy) const {
     return "double";
   case LongDouble:
     return "long double";
+  case Float128:
+    return "__float128";
   case WChar_S:
   case WChar_U:
     return Policy.MSWChar ? "__wchar_t" : "wchar_t";
diff --git a/clang/lib/AST/TypeLoc.cpp b/clang/lib/AST/TypeLoc.cpp
index 05e5a627b75..78947d18f95 100644
--- a/clang/lib/AST/TypeLoc.cpp
+++ b/clang/lib/AST/TypeLoc.cpp
@@ -320,6 +320,7 @@ TypeSpecifierType BuiltinTypeLoc::getWrittenTypeSpec() const {
   case BuiltinType::Float:
   case BuiltinType::Double:
   case BuiltinType::LongDouble:
+  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 ff44a570de1..ac6cef9d084 100644
--- a/clang/lib/Analysis/PrintfFormatString.cpp
+++ b/clang/lib/Analysis/PrintfFormatString.cpp
@@ -616,6 +616,7 @@ bool PrintfSpecifier::fixType(QualType QT, const LangOptions &LangOpt,
   case BuiltinType::UInt128:
   case BuiltinType::Int128:
   case BuiltinType::Half:
+  case BuiltinType::Float128:
     // Various types which are non-trivial to correct.
     return false;
 
diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index 40d6001e532..c287073ead9 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -46,6 +46,7 @@ TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
   DoubleAlign = 64;
   LongDoubleWidth = 64;
   LongDoubleAlign = 64;
+  Float128Align = 128;
   LargeArrayMinWidth = 0;
   LargeArrayAlign = 0;
   MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
@@ -72,6 +73,7 @@ TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
   FloatFormat = &llvm::APFloat::IEEEsingle;
   DoubleFormat = &llvm::APFloat::IEEEdouble;
   LongDoubleFormat = &llvm::APFloat::IEEEdouble;
+  Float128Format = &llvm::APFloat::IEEEquad;
   MCountName = "mcount";
   RegParmMax = 0;
   SSERegParmMax = 0;
@@ -223,6 +225,8 @@ TargetInfo::RealType TargetInfo::getRealTypeByWidth(unsigned BitWidth) const {
     if (&getLongDoubleFormat() == &llvm::APFloat::PPCDoubleDouble ||
         &getLongDoubleFormat() == &llvm::APFloat::IEEEquad)
       return LongDouble;
+    if (hasFloat128Type())
+      return Float128;
     break;
   }
 
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 7639b04d25a..4cce9cbd8a2 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -806,6 +806,7 @@ class PPCTargetInfo : public TargetInfo {
   bool HasHTM;
   bool HasBPERMD;
   bool HasExtDiv;
+  bool HasFloat128;
 
 protected:
   std::string ABI;
@@ -814,7 +815,7 @@ public:
   PPCTargetInfo(const llvm::Triple &Triple, const TargetOptions &)
     : TargetInfo(Triple), HasVSX(false), HasP8Vector(false),
       HasP8Crypto(false), HasDirectMove(false), HasQPX(false), HasHTM(false),
-      HasBPERMD(false), HasExtDiv(false) {
+      HasBPERMD(false), HasExtDiv(false), HasFloat128(false) {
     BigEndian = (Triple.getArch() != llvm::Triple::ppc64le);
     SimdDefaultAlign = 128;
     LongDoubleWidth = LongDoubleAlign = 128;
@@ -1058,6 +1059,9 @@ public:
            LongDoubleFormat == &llvm::APFloat::PPCDoubleDouble &&
            getTriple().isOSBinFormatELF();
   }
+  bool hasFloat128Type() const override {
+    return HasFloat128;
+  }
 };
 
 const Builtin::Info PPCTargetInfo::BuiltinInfo[] = {
@@ -1089,6 +1093,8 @@ bool PPCTargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasQPX = true;
     } else if (Feature == "+htm") {
       HasHTM = true;
+    } else if (Feature == "+float128") {
+      HasFloat128 = true;
     }
     // TODO: Finish this list and add an assert that we've handled them
     // all.
@@ -1246,6 +1252,8 @@ void PPCTargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__CRYPTO__");
   if (HasHTM)
     Builder.defineMacro("__HTM__");
+  if (HasFloat128)
+    Builder.defineMacro("__FLOAT128__");
 
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");
@@ -1296,6 +1304,13 @@ static bool ppcUserFeaturesCheck(DiagnosticsEngine &Diags,
                                                      << "-mno-vsx";
       return false;
     }
+
+    if (std::find(FeaturesVec.begin(), FeaturesVec.end(), "+float128") !=
+        FeaturesVec.end()) {
+      Diags.Report(diag::err_opt_not_valid_with_opt) << "-mfloat128"
+                                                     << "-mno-vsx";
+      return false;
+    }
   }
 
   return true;
@@ -1364,6 +1379,7 @@ bool PPCTargetInfo::hasFeature(StringRef Feature) const {
     .Case("htm", HasHTM)
     .Case("bpermd", HasBPERMD)
     .Case("extdiv", HasExtDiv)
+    .Case("float128", HasFloat128)
     .Default(false);
 }
 
@@ -1373,19 +1389,19 @@ void PPCTargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
   // as well. Do the inverse if we're disabling vsx. We'll diagnose any user
   // incompatible options.
   if (Enabled) {
-    if (Name == "vsx") {
-     Features[Name] = true;
-    } else if (Name == "direct-move") {
+    if (Name == "direct-move") {
       Features[Name] = Features["vsx"] = true;
     } else if (Name == "power8-vector") {
       Features[Name] = Features["vsx"] = true;
+    } else if (Name == "float128") {
+      Features[Name] = Features["vsx"] = true;
     } else {
       Features[Name] = true;
     }
   } else {
     if (Name == "vsx") {
       Features[Name] = Features["direct-move"] = Features["power8-vector"] =
-          false;
+          Features["float128"] = false;
     } else {
       Features[Name] = false;
     }
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 13ee0fb1d99..4b7657bb352 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -528,7 +528,13 @@ llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
   case BuiltinType::Half:
   case BuiltinType::Float:
   case BuiltinType::LongDouble:
+  case BuiltinType::Float128:
   case BuiltinType::Double:
+    // FIXME: For targets where long double and __float128 have the same size,
+    // they are currently indistinguishable in the debugger without some
+    // special treatment. However, there is currently no consensus on encoding
+    // and this should be updated once a DWARF encoding exists for distinct
+    // floating point types of the same size.
     Encoding = llvm::dwarf::DW_ATE_float;
     break;
   }
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 1fd79d0e0ed..8f122963a1f 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1796,15 +1796,19 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
       amt = llvm::ConstantFP::get(VMContext,
                                   llvm::APFloat(static_cast<double>(amount)));
     else {
-      // Remaining types are either Half or LongDouble.  Convert from float.
+      // Remaining types are Half, LongDouble or __float128. Convert from float.
       llvm::APFloat F(static_cast<float>(amount));
       bool ignored;
+      const llvm::fltSemantics *FS;
       // Don't use getFloatTypeSemantics because Half isn't
       // necessarily represented using the "half" LLVM type.
-      F.convert(value->getType()->isHalfTy()
-                    ? CGF.getTarget().getHalfFormat()
-                    : CGF.getTarget().getLongDoubleFormat(),
-                llvm::APFloat::rmTowardZero, &ignored);
+      if (value->getType()->isFP128Ty())
+        FS = &CGF.getTarget().getFloat128Format();
+      else if (value->getType()->isHalfTy())
+        FS = &CGF.getTarget().getHalfFormat();
+      else
+        FS = &CGF.getTarget().getLongDoubleFormat();
+      F.convert(*FS, llvm::APFloat::rmTowardZero, &ignored);
       amt = llvm::ConstantFP::get(VMContext, F);
     }
     value = Builder.CreateFAdd(value, amt, isInc ? "inc" : "dec");
diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index 33e53a6cbe2..ebe55c70d81 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -449,6 +449,7 @@ llvm::Type *CodeGenTypes::ConvertType(QualType T) {
     case BuiltinType::Float:
     case BuiltinType::Double:
     case BuiltinType::LongDouble:
+    case BuiltinType::Float128:
       ResultType = getTypeForFormat(getLLVMContext(),
                                     Context.getFloatTypeSemantics(T),
                                     /* UseNativeHalf = */ false);
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index b44e8405334..52e519f3044 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2530,6 +2530,7 @@ static bool TypeInfoIsInStandardLibrary(const BuiltinType *Ty) {
     case BuiltinType::Float:
     case BuiltinType::Double:
     case BuiltinType::LongDouble:
+    case BuiltinType::Float128:
     case BuiltinType::Char16:
     case BuiltinType::Char32:
     case BuiltinType::Int128:
@@ -3349,8 +3350,8 @@ void ItaniumCXXABI::EmitFundamentalRTTIDescriptors() {
       getContext().UnsignedLongLongTy, getContext().Int128Ty,
       getContext().UnsignedInt128Ty,   getContext().HalfTy,
       getContext().FloatTy,            getContext().DoubleTy,
-      getContext().LongDoubleTy,       getContext().Char16Ty,
-      getContext().Char32Ty,
+      getContext().LongDoubleTy,       getContext().Float128Ty,
+      getContext().Char16Ty,           getContext().Char32Ty
   };
   for (const QualType &FundamentalType : FundamentalTypes)
     EmitFundamentalRTTIDescriptor(FundamentalType);
diff --git a/clang/lib/Format/FormatToken.cpp b/clang/lib/Format/FormatToken.cpp
index d6cd450d892..2ae4ddcfd08 100644
--- a/clang/lib/Format/FormatToken.cpp
+++ b/clang/lib/Format/FormatToken.cpp
@@ -53,6 +53,7 @@ bool FormatToken::isSimpleTypeSpecifier() const {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_wchar_t:
   case tok::kw_bool:
   case tok::kw___underlying_type:
diff --git a/clang/lib/Index/USRGeneration.cpp b/clang/lib/Index/USRGeneration.cpp
index 65de75b5c4f..40283dcd686 100644
--- a/clang/lib/Index/USRGeneration.cpp
+++ b/clang/lib/Index/USRGeneration.cpp
@@ -618,6 +618,8 @@ void USRGenerator::VisitType(QualType T) {
           c = 'd'; break;
         case BuiltinType::LongDouble:
           c = 'D'; break;
+        case BuiltinType::Float128:
+          c = 'Q'; break;
         case BuiltinType::NullPtr:
           c = 'n'; break;
 #define BUILTIN_TYPE(Id, SingletonId)
diff --git a/clang/lib/Lex/LiteralSupport.cpp b/clang/lib/Lex/LiteralSupport.cpp
index 27c80b93015..e68b82fb499 100644
--- a/clang/lib/Lex/LiteralSupport.cpp
+++ b/clang/lib/Lex/LiteralSupport.cpp
@@ -525,6 +525,7 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
   isHalf = false;
   isFloat = false;
   isImaginary = false;
+  isFloat128 = false;
   MicrosoftInteger = 0;
   hadError = false;
 
@@ -567,9 +568,17 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
     case 'f':      // FP Suffix for "float"
     case 'F':
       if (!isFPConstant) break;  // Error for integer constant.
-      if (isHalf || isFloat || isLong) break; // HF, FF, LF invalid.
+      if (isHalf || isFloat || isLong || isFloat128)
+        break; // HF, FF, LF, QF invalid.
       isFloat = true;
       continue;  // Success.
+    case 'q':    // FP Suffix for "__float128"
+    case 'Q':
+      if (!isFPConstant) break;  // Error for integer constant.
+      if (isHalf || isFloat || isLong || isFloat128)
+        break; // HQ, FQ, LQ, QQ invalid.
+      isFloat128 = true;
+      continue;  // Success.
     case 'u':
     case 'U':
       if (isFPConstant) break;  // Error for floating constant.
@@ -579,7 +588,7 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
     case 'l':
     case 'L':
       if (isLong || isLongLong) break;  // Cannot be repeated.
-      if (isHalf || isFloat) break;     // LH, LF invalid.
+      if (isHalf || isFloat || isFloat128) break;     // LH, LF, LQ invalid.
 
       // Check for long long.  The L's need to be adjacent and the same case.
       if (s[1] == s[0]) {
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index b06eda9d23c..ebe26cfb2dd 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3306,6 +3306,10 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
       isInvalid = DS.SetTypeSpecType(DeclSpec::TST_double, Loc, PrevSpec,
                                      DiagID, Policy);
       break;
+    case tok::kw___float128:
+      isInvalid = DS.SetTypeSpecType(DeclSpec::TST_float128, Loc, PrevSpec,
+                                     DiagID, Policy);
+      break;
     case tok::kw_wchar_t:
       isInvalid = DS.SetTypeSpecType(DeclSpec::TST_wchar, Loc, PrevSpec,
                                      DiagID, Policy);
@@ -4300,6 +4304,7 @@ bool Parser::isKnownToBeTypeSpecifier(const Token &Tok) const {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_bool:
   case tok::kw__Bool:
   case tok::kw__Decimal32:
@@ -4374,6 +4379,7 @@ bool Parser::isTypeSpecifierQualifier() {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_bool:
   case tok::kw__Bool:
   case tok::kw__Decimal32:
@@ -4528,6 +4534,7 @@ bool Parser::isDeclarationSpecifier(bool DisambiguatingWithExpression) {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_bool:
   case tok::kw__Bool:
   case tok::kw__Decimal32:
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 2745c337765..5b7c839454a 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -1166,6 +1166,7 @@ ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_void:
   case tok::kw_typename:
   case tok::kw_typeof:
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index afed9b1ab46..b569e7aeba1 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___float128:
+    DS.SetTypeSpecType(DeclSpec::TST_float128, Loc, PrevSpec, DiagID, Policy);
+    break;
   case tok::kw_wchar_t:
     DS.SetTypeSpecType(DeclSpec::TST_wchar, Loc, PrevSpec, DiagID, Policy);
     break;
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index 747d0a982cf..4d4bd806f3c 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -946,6 +946,7 @@ Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
   case tok::kw_char:
   case tok::kw_const:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_enum:
   case tok::kw_half:
   case tok::kw_float:
@@ -1426,6 +1427,7 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_void:
   case tok::annot_decltype:
     if (NextToken().is(tok::l_paren))
@@ -1517,6 +1519,7 @@ bool Parser::isCXXDeclarationSpecifierAType() {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_void:
   case tok::kw___unknown_anytype:
   case tok::kw___auto_type:
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index 4bc1d3423b4..ddfe6257cf4 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -289,6 +289,7 @@ bool Declarator::isDeclarationOfFunction() const {
     case TST_decimal32:
     case TST_decimal64:
     case TST_double:
+    case TST_float128:
     case TST_enum:
     case TST_error:
     case TST_float:
@@ -457,6 +458,7 @@ 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_float128:    return "__float128";
   case DeclSpec::TST_bool:        return Policy.Bool ? "bool" : "_Bool";
   case DeclSpec::TST_decimal32:   return "_Decimal32";
   case DeclSpec::TST_decimal64:   return "_Decimal64";
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index b0e79f6f0e7..13002ba19a5 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -108,6 +108,7 @@ bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
+  case tok::kw___float128:
   case tok::kw_wchar_t:
   case tok::kw_bool:
   case tok::kw___underlying_type:
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index a4b1525d942..fcc608fa1f5 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -1155,6 +1155,48 @@ static QualType handleFloatConversion(Sema &S, ExprResult &LHS,
                                     /*convertFloat=*/!IsCompAssign);
 }
 
+/// \brief Diagnose attempts to convert between __float128 and long double if
+/// there is no support for such conversion. Helper function of
+/// UsualArithmeticConversions().
+static bool unsupportedTypeConversion(const Sema &S, QualType LHSType,
+                                      QualType RHSType) {
+  /*  No issue converting if at least one of the types is not a floating point
+      type or the two types have the same rank.
+  */
+  if (!LHSType->isFloatingType() || !RHSType->isFloatingType() ||
+      S.Context.getFloatingTypeOrder(LHSType, RHSType) == 0)
+    return false;
+
+  assert(LHSType->isFloatingType() && RHSType->isFloatingType() &&
+         "The remaining types must be floating point types.");
+
+  auto *LHSComplex = LHSType->getAs<ComplexType>();
+  auto *RHSComplex = RHSType->getAs<ComplexType>();
+
+  QualType LHSElemType = LHSComplex ?
+    LHSComplex->getElementType() : LHSType;
+  QualType RHSElemType = RHSComplex ?
+    RHSComplex->getElementType() : RHSType;
+
+  // No issue if the two types have the same representation
+  if (&S.Context.getFloatTypeSemantics(LHSElemType) ==
+      &S.Context.getFloatTypeSemantics(RHSElemType))
+    return false;
+
+  bool Float128AndLongDouble = (LHSElemType == S.Context.Float128Ty &&
+                                RHSElemType == S.Context.LongDoubleTy);
+  Float128AndLongDouble |= (LHSElemType == S.Context.LongDoubleTy &&
+                            RHSElemType == S.Context.Float128Ty);
+
+  /* We've handled the situation where __float128 and long double have the same
+     representation. The only other allowable conversion is if long double is
+     really just double.
+  */
+  return Float128AndLongDouble &&
+    (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) !=
+     &llvm::APFloat::IEEEdouble);
+}
+
 typedef ExprResult PerformCastFn(Sema &S, Expr *operand, QualType toType);
 
 namespace {
@@ -1318,6 +1360,11 @@ QualType Sema::UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
 
   // At this point, we have two different arithmetic types.
 
+  // Diagnose attempts to convert between __float128 and long double where
+  // such conversions currently can't be handled.
+  if (unsupportedTypeConversion(*this, LHSType, RHSType))
+    return QualType();
+
   // Handle complex types first (C99 6.3.1.8p1).
   if (LHSType->isComplexType() || RHSType->isComplexType())
     return handleComplexFloatConversion(*this, LHS, RHS, LHSType, RHSType,
@@ -3325,10 +3372,12 @@ ExprResult Sema::ActOnNumericConstant(const Token &Tok, Scope *UDLScope) {
       }
     } else if (Literal.isFloat)
       Ty = Context.FloatTy;
-    else if (!Literal.isLong)
-      Ty = Context.DoubleTy;
-    else
+    else if (Literal.isLong)
       Ty = Context.LongDoubleTy;
+    else if (Literal.isFloat128)
+      Ty = Context.Float128Ty;
+    else
+      Ty = Context.DoubleTy;
 
     Res = BuildFloatingLiteral(*this, Literal, Ty, Tok.getLocation());
 
@@ -6602,6 +6651,15 @@ QualType Sema::CheckConditionalOperands(ExprResult &Cond, ExprResult &LHS,
   QualType LHSTy = LHS.get()->getType();
   QualType RHSTy = RHS.get()->getType();
 
+  // Diagnose attempts to convert between __float128 and long double where
+  // such conversions currently can't be handled.
+  if (unsupportedTypeConversion(*this, LHSTy, RHSTy)) {
+    Diag(QuestionLoc,
+         diag::err_typecheck_cond_incompatible_operands) << LHSTy << RHSTy
+      << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
+    return QualType();
+  }
+
   // OpenCL v2.0 s6.12.5 - Blocks cannot be used as expressions of the ternary
   // selection operator (?:).
   if (getLangOpts().OpenCL &&
@@ -7335,6 +7393,11 @@ Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
     return Incompatible;
   }
 
+  // Diagnose attempts to convert between __float128 and long double where
+  // such conversions currently can't be handled.
+  if (unsupportedTypeConversion(*this, LHSType, RHSType))
+    return Incompatible;
+
   // Arithmetic conversions.
   if (LHSType->isArithmeticType() && RHSType->isArithmeticType() &&
       !(getLangOpts().CPlusPlus && LHSType->isEnumeralType())) {
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 87c2ded7c8d..4063464c45e 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -5171,6 +5171,12 @@ QualType Sema::CXXCheckConditionalOperands(ExprResult &Cond, ExprResult &LHS,
     QualType ResTy = UsualArithmeticConversions(LHS, RHS);
     if (LHS.isInvalid() || RHS.isInvalid())
       return QualType();
+    if (ResTy.isNull()) {
+      Diag(QuestionLoc,
+           diag::err_typecheck_cond_incompatible_operands) << LTy << RTy
+        << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
+      return QualType();
+    }
 
     LHS = ImpCastExprToType(LHS.get(), ResTy, PrepareScalarCast(LHS, ResTy));
     RHS = ImpCastExprToType(RHS.get(), ResTy, PrepareScalarCast(RHS, ResTy));
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 08133d68899..fdf5346d92e 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -681,13 +681,6 @@ static bool LookupBuiltin(Sema &S, LookupResult &R) {
       NameKind == Sema::LookupRedeclarationWithLinkage) {
     IdentifierInfo *II = R.getLookupName().getAsIdentifierInfo();
     if (II) {
-      if (S.getLangOpts().CPlusPlus11 && S.getLangOpts().GNUMode &&
-          II == S.getFloat128Identifier()) {
-        // libstdc++4.7's type_traits expects type __float128 to exist, so
-        // insert a dummy type to make that header build in gnu++11 mode.
-        R.addDecl(S.getASTContext().getFloat128StubType());
-        return true;
-      }
       if (S.getLangOpts().CPlusPlus && NameKind == Sema::LookupOrdinaryName &&
           II == S.getASTContext().getMakeIntegerSeqName()) {
         R.addDecl(S.getASTContext().getMakeIntegerSeqDecl());
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 034b090fdf3..e3a72c1e22d 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -1671,6 +1671,20 @@ static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
     SCS.Second = ICK_Complex_Real;
     FromType = ToType.getUnqualifiedType();
   } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
+    // FIXME: disable conversions between long double and __float128 if
+    // their representation is different until there is back end support
+    // We of course allow this conversion if long double is really double.
+    if (&S.Context.getFloatTypeSemantics(FromType) !=
+        &S.Context.getFloatTypeSemantics(ToType)) {
+      bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty &&
+                                    ToType == S.Context.LongDoubleTy) ||
+                                   (FromType == S.Context.LongDoubleTy &&
+                                    ToType == S.Context.Float128Ty));
+      if (Float128AndLongDouble &&
+          (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) !=
+           &llvm::APFloat::IEEEdouble))
+        return false;
+    }
     // Floating point conversions (C++ 4.8).
     SCS.Second = ICK_Floating_Conversion;
     FromType = ToType.getUnqualifiedType();
@@ -1973,7 +1987,8 @@ bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
       if (!getLangOpts().CPlusPlus &&
           (FromBuiltin->getKind() == BuiltinType::Float ||
            FromBuiltin->getKind() == BuiltinType::Double) &&
-          (ToBuiltin->getKind() == BuiltinType::LongDouble))
+          (ToBuiltin->getKind() == BuiltinType::LongDouble ||
+           ToBuiltin->getKind() == BuiltinType::Float128))
         return true;
 
       // Half can be promoted to float.
@@ -7198,13 +7213,13 @@ class BuiltinOperatorOverloadBuilder {
   // provided via the getArithmeticType() method below.
   // The "promoted arithmetic types" are the arithmetic
   // types are that preserved by promotion (C++ [over.built]p2).
-  static const unsigned FirstIntegralType = 3;
-  static const unsigned LastIntegralType = 20;
-  static const unsigned FirstPromotedIntegralType = 3,
-                        LastPromotedIntegralType = 11;
+  static const unsigned FirstIntegralType = 4;
+  static const unsigned LastIntegralType = 21;
+  static const unsigned FirstPromotedIntegralType = 4,
+                        LastPromotedIntegralType = 12;
   static const unsigned FirstPromotedArithmeticType = 0,
-                        LastPromotedArithmeticType = 11;
-  static const unsigned NumArithmeticTypes = 20;
+                        LastPromotedArithmeticType = 12;
+  static const unsigned NumArithmeticTypes = 21;
 
   /// \brief Get the canonical type for a given arithmetic type index.
   CanQualType getArithmeticType(unsigned index) {
@@ -7215,6 +7230,7 @@ class BuiltinOperatorOverloadBuilder {
       &ASTContext::FloatTy,
       &ASTContext::DoubleTy,
       &ASTContext::LongDoubleTy,
+      &ASTContext::Float128Ty,
 
       // Start of integral types.
       &ASTContext::IntTy,
diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index c23b5a2adc5..52a1ad545a5 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -727,6 +727,7 @@ bool Sema::containsUnexpandedParameterPacks(Declarator &D) {
   case TST_half:
   case TST_float:
   case TST_double:
+  case TST_float128:
   case TST_bool:
   case TST_decimal32:
   case TST_decimal64:
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index cf47d867c8b..4d68f4c1cfb 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1355,7 +1355,8 @@ static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
   }
   case DeclSpec::TST_int128:
     if (!S.Context.getTargetInfo().hasInt128Type())
-      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_int128_unsupported);
+      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
+        << "__int128";
     if (DS.getTypeSpecSign() == DeclSpec::TSS_unsigned)
       Result = Context.UnsignedInt128Ty;
     else
@@ -1377,6 +1378,12 @@ static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
       declarator.setInvalidType(true);
     }
     break;
+  case DeclSpec::TST_float128:
+    if (!S.Context.getTargetInfo().hasFloat128Type())
+      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
+        << "__float128";
+    Result = Context.Float128Ty;
+    break;
   case DeclSpec::TST_bool: Result = Context.BoolTy; break; // _Bool or bool
     break;
   case DeclSpec::TST_decimal32:    // _Decimal32
@@ -6959,13 +6966,6 @@ bool Sema::RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
   if (!Diagnoser)
     return true;
 
-  // We have an incomplete type. Produce a diagnostic.
-  if (Ident___float128 &&
-      T == Context.getTypeDeclType(Context.getFloat128StubType())) {
-    Diag(Loc, diag::err_typecheck_decl_incomplete_type___float128);
-    return true;
-  }
-
   Diagnoser->diagnose(*this, Loc, T);
 
   // If the type was a forward declaration of a class/struct/union
diff --git a/clang/lib/Serialization/ASTCommon.cpp b/clang/lib/Serialization/ASTCommon.cpp
index 2382f8ea4bd..792fac99e58 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::Float128:
+    ID = PREDEF_TYPE_FLOAT128_ID;
+    break;
   case BuiltinType::NullPtr:
     ID = PREDEF_TYPE_NULLPTR_ID;
     break;
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 0c2522311ac..df1418649d6 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -6059,6 +6059,9 @@ QualType ASTReader::GetType(TypeID ID) {
     case PREDEF_TYPE_LONGDOUBLE_ID:
       T = Context.LongDoubleTy;
       break;
+    case PREDEF_TYPE_FLOAT128_ID:
+      T = Context.Float128Ty;
+      break;
     case PREDEF_TYPE_OVERLOAD_ID:
       T = Context.OverloadTy;
       break;