Switch to APFloat constructor taking fltSemantics.

This change also makes the serialisation store the required semantics,
fixing an issue where PPC128 was always assumed when re-reading a
128-bit value.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173139 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ASTWriterStmt.cpp b/lib/Serialization/ASTWriterStmt.cpp
index 0c6dc5d..6b96c50 100644
--- a/lib/Serialization/ASTWriterStmt.cpp
+++ b/lib/Serialization/ASTWriterStmt.cpp
@@ -324,8 +324,9 @@
 
 void ASTStmtWriter::VisitFloatingLiteral(FloatingLiteral *E) {
   VisitExpr(E);
-  Writer.AddAPFloat(E->getValue(), Record);
+  Record.push_back(E->getRawSemantics());
   Record.push_back(E->isExact());
+  Writer.AddAPFloat(E->getValue(), Record);
   Writer.AddSourceLocation(E->getLocation(), Record);
   Code = serialization::EXPR_FLOATING_LITERAL;
 }