diff --git a/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/deque_iterators/1.cc b/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/deque_iterators/1.cc
index 14a75358db4..65aafdcf03d 100644
--- a/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/deque_iterators/1.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/deque_iterators/1.cc
@@ -15,6 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-timeout-factor 2 { target debug-mode } }
+
 #include <algorithm>
 #include <vector>
 #include <deque>
diff --git a/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_map_rand_debug.cc b/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_map_rand_debug.cc
index 627f3864347..411a906d598 100644
--- a/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_map_rand_debug.cc
+++ b/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_map_rand_debug.cc
@@ -2,7 +2,7 @@
 // { dg-require-time "" }
 // This can take long on simulators, timing out the test.
 // { dg-options "-DITERATIONS=5" { target simulator } }
-// { dg-timeout-factor 2.0 }
+// { dg-timeout-factor 3.0 }
 
 // -*- C++ -*-
 
diff --git a/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_set_rand_debug.cc b/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_set_rand_debug.cc
index cd7b1118e26..dd1b45c3491 100644
--- a/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_set_rand_debug.cc
+++ b/libstdc++-v3/testsuite/ext/pb_ds/regression/tree_set_rand_debug.cc
@@ -2,7 +2,7 @@
 // { dg-require-time "" }
 // This can take long on simulators, timing out the test.
 // { dg-options "-DITERATIONS=5" { target simulator } }
-// { dg-timeout-factor 2.0 }
+// { dg-timeout-factor 3.0 }
 
 // -*- C++ -*-
 
diff --git a/libstdc++-v3/testsuite/lib/libstdc++.exp b/libstdc++-v3/testsuite/lib/libstdc++.exp
index 35817a8870a..aeb881f91a6 100644
--- a/libstdc++-v3/testsuite/lib/libstdc++.exp
+++ b/libstdc++-v3/testsuite/lib/libstdc++.exp
@@ -1004,6 +1004,11 @@ proc check_v3_target_debug_mode { } {
     }]
 }
 
+# Define "debug-mode" as an effective-target keyword.
+proc check_effective_target_debug-mode { } {
+    return [check_v3_target_debug_mode]
+}
+
 # Return 1 if normal mode is active, 0 otherwise.
 # i.e. neither Debug Mode nor Parallel Mode is active.
 proc check_v3_target_normal_mode { } {