Hack Expr::isConstantExpr() to allow for __builtin_types_compatible_p.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40705 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/AST/Expr.cpp b/AST/Expr.cpp
index 5fcd31a..8f1335c 100644
--- a/AST/Expr.cpp
+++ b/AST/Expr.cpp
@@ -305,6 +305,9 @@
     Result.setIsUnsigned(!getType()->isSignedIntegerType());
     break;
   }
+  case TypesCompatibleExprClass:
+    Result = cast<TypesCompatibleExpr>(this)->typesAreCompatible();
+    break;
   case DeclRefExprClass:
     if (const EnumConstantDecl *D = 
           dyn_cast<EnumConstantDecl>(cast<DeclRefExpr>(this)->getDecl())) {