Provide half floating point support as a storage only type.
Lack of half FP was a regression compared to llvm-gcc.

llvm-svn: 142016
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 39a9ef7..c7a9b40 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -391,6 +391,7 @@
   case BuiltinType::WChar_S:
   case BuiltinType::LongLong:  Encoding = llvm::dwarf::DW_ATE_signed; break;
   case BuiltinType::Bool:      Encoding = llvm::dwarf::DW_ATE_boolean; break;
+  case BuiltinType::Half:
   case BuiltinType::Float:
   case BuiltinType::LongDouble:
   case BuiltinType::Double:    Encoding = llvm::dwarf::DW_ATE_float; break;