Revert 266186 as it breaks anything that includes type_traits on some platforms

Since this patch provided support for the __float128 type but disabled it
on all platforms by default, some platforms can't compile type_traits with
-std=gnu++11 since there is a specialization with __float128.
This reverts the patch until D19125 is approved (i.e. we know which platforms
need this support enabled).

llvm-svn: 266460
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 54b5f2f..6fd0032 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -528,13 +528,7 @@
   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 8f122963..1fd79d0 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1796,19 +1796,15 @@
       amt = llvm::ConstantFP::get(VMContext,
                                   llvm::APFloat(static_cast<double>(amount)));
     else {
-      // Remaining types are Half, LongDouble or __float128. Convert from float.
+      // Remaining types are either Half or LongDouble.  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.
-      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);
+      F.convert(value->getType()->isHalfTy()
+                    ? CGF.getTarget().getHalfFormat()
+                    : CGF.getTarget().getLongDoubleFormat(),
+                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 ebe55c7..33e53a6 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -449,7 +449,6 @@
     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 52e519f..b44e840 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2530,7 +2530,6 @@
     case BuiltinType::Float:
     case BuiltinType::Double:
     case BuiltinType::LongDouble:
-    case BuiltinType::Float128:
     case BuiltinType::Char16:
     case BuiltinType::Char32:
     case BuiltinType::Int128:
@@ -3350,8 +3349,8 @@
       getContext().UnsignedLongLongTy, getContext().Int128Ty,
       getContext().UnsignedInt128Ty,   getContext().HalfTy,
       getContext().FloatTy,            getContext().DoubleTy,
-      getContext().LongDoubleTy,       getContext().Float128Ty,
-      getContext().Char16Ty,           getContext().Char32Ty
+      getContext().LongDoubleTy,       getContext().Char16Ty,
+      getContext().Char32Ty,
   };
   for (const QualType &FundamentalType : FundamentalTypes)
     EmitFundamentalRTTIDescriptor(FundamentalType);