Handle __builtin___CFStringMakeConstantString in Expr::Evaluate.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60581 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 9eeaa86..28440f4 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -207,6 +207,7 @@
 
   APValue VisitBinaryOperator(const BinaryOperator *E);
   APValue VisitCastExpr(const CastExpr* E);
+  APValue VisitCallExpr(CallExpr *E);
   APValue VisitUnaryOperator(const UnaryOperator *E);
   APValue VisitObjCStringLiteral(ObjCStringLiteral *E)
       { return APValue(E, 0); }
@@ -266,7 +267,6 @@
 
   return APValue();
 }
-  
 
 APValue PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
   const Expr* SubExpr = E->getSubExpr();
@@ -299,6 +299,15 @@
   return APValue();
 }  
 
+APValue PointerExprEvaluator::VisitCallExpr(CallExpr *E)
+{
+  switch (E->isBuiltinCall()) {
+    default: return APValue();
+    case Builtin::BI__builtin___CFStringMakeConstantString:
+      return APValue(E, 0);
+  }
+}
+
 APValue PointerExprEvaluator::VisitConditionalOperator(ConditionalOperator *E) {
   bool BoolResult;
   if (!HandleConversionToBool(E->getCond(), BoolResult, Info))