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/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 64fd40b..71489cb 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -3629,7 +3629,6 @@
     SmallVector<APValue, 4> Elts;
     if (EltTy->isRealFloatingType()) {
       const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
-      bool isIEESem = &Sem != &APFloat::PPCDoubleDouble;
       unsigned FloatEltSize = EltSize;
       if (&Sem == &APFloat::x87DoubleExtended)
         FloatEltSize = 80;
@@ -3639,7 +3638,7 @@
           Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
         else
           Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
-        Elts.push_back(APValue(APFloat(Elt, isIEESem)));
+        Elts.push_back(APValue(APFloat(Sem, Elt)));
       }
     } else if (EltTy->isIntegerType()) {
       for (unsigned i = 0; i < NElts; i++) {