Enable support for __float128 in Clang and enable it on pertinent platforms

This patch corresponds to reviews:
http://reviews.llvm.org/D15120
http://reviews.llvm.org/D19125

It adds support for the __float128 keyword, literals and target feature to
enable it. Based on the latter of the two aforementioned reviews, this feature
is enabled on Linux on i386/X86 as well as SystemZ.
This is also the second attempt in commiting this feature. The first attempt
did not enable it on required platforms which caused failures when compiling
type_traits with -std=gnu++11.

If you see failures with compiling this header on your platform after this
commit, it is likely that your platform needs to have this feature enabled.

llvm-svn: 268898

2 files changed, 6 insertions, 0 deletions

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 5d459ac9fb6..0f4a7d32667 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -6040,6 +6040,9 @@ 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;