diff --git a/gcc/testsuite/g++.dg/warn/Wchar-subscripts-2.C b/gcc/testsuite/g++.dg/warn/Wchar-subscripts-2.C
index 5d19cd37ea4..2170cb20616 100644
--- a/gcc/testsuite/g++.dg/warn/Wchar-subscripts-2.C
+++ b/gcc/testsuite/g++.dg/warn/Wchar-subscripts-2.C
@@ -2,9 +2,11 @@
 // { dg-do compile }
 // { dg-options "-Wchar-subscripts" }
 
+extern volatile char bla;
+
 char foo (const char *s)
 {
-    return s [s ['\x80']];          // { dg-warning "array subscript" }
+    return s [bla];          // { dg-warning "array subscript" }
 }
 
 int main ()