testsuite: run C++11 tests in C++11 mode

A recent change missed updating constexpr-mutable3.C because it wasn't run
in C++11 mode even though it checks the behavior for { target c++11_only }.

gcc/testsuite/ChangeLog:

	* lib/g++-dg.exp (g++-dg-runtest): Check for c++11_only.

diff --git a/gcc/testsuite/lib/g++-dg.exp b/gcc/testsuite/lib/g++-dg.exp
index 046d63170c8c85419fea40a3c58579feb9aaed71..142c52c8426a8ae25f7d7fa3af0452972443646e 100644 (file)
--- a/gcc/testsuite/lib/g++-dg.exp
+++ b/gcc/testsuite/lib/g++-dg.exp
@@ -55,13 +55,16 @@ proc g++-dg-runtest { testcases flags default-extra-flags } {
            } else {
                # If the test requires a newer C++ version than which
                # is tested by default, use that C++ version for that
-               # single test.  This should be updated or commented
-               # out whenever the default std_list is updated or newer
-               # C++ effective target is added.
+               # single test.  Or if a test checks behavior specifically for
+               # one C++ version, include that version in the default list.
+               # These should be adjusted whenever the default std_list is
+               # updated or newer C++ effective target is added.
                if [search_for $test "\{ dg-do * \{ target c++23"] {
                    set std_list { 23 26 }
                } elseif [search_for $test "\{ dg-do * \{ target c++26"] {
                    set std_list { 26 }
+               } elseif [search_for $test "c++11_only"] {
+                   set std_list { 98 11 14 20 }
                } else {
                    set std_list { 98 14 17 20 }
                }