Fixed isConstantInitializer for __builtin_choose_expr.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114820 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index b31ec23..dbfe2d5 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1764,6 +1764,9 @@
   case ParenExprClass:
     return cast<ParenExpr>(this)->getSubExpr()
       ->isConstantInitializer(Ctx, IsForRef);
+  case ChooseExprClass:
+    return cast<ChooseExpr>(this)->getChosenSubExpr(Ctx)
+      ->isConstantInitializer(Ctx, IsForRef);
   case UnaryOperatorClass: {
     const UnaryOperator* Exp = cast<UnaryOperator>(this);
     if (Exp->getOpcode() == UO_Extension)