diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-subgroups-2.c b/gcc/testsuite/gcc.dg/vect/bb-slp-subgroups-2.c
index ead8d92f202..9431bcb9d5c 100644
--- a/gcc/testsuite/gcc.dg/vect/bb-slp-subgroups-2.c
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-subgroups-2.c
@@ -39,4 +39,5 @@ main (int argc, char **argv)
 }
 
 /* { dg-final { scan-tree-dump-times "Basic block will be vectorized using SLP" 1 "slp2" } } */
-/* { dg-final { scan-tree-dump-times "optimized: basic block" 2 "slp2" } } */
+/* { dg-final { scan-tree-dump-times "optimized: basic block" 2 "slp2" { target { ! vect256 } } } } */
+/* { dg-final { scan-tree-dump-times "optimized: basic block" 1 "slp2" { target { vect256 } } } } */
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 5b5f8655184..d4623ee6b45 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -8634,6 +8634,24 @@ proc check_effective_target_vect_variable_length { } {
     return [expr { [lindex [available_vector_sizes] 0] == 0 }]
 }
 
+# Return 1 if the target supports vectors of 512 bits.
+
+proc check_effective_target_vect512 { } {
+    return [expr { [lsearch -exact [available_vector_sizes] 512] >= 0 }]
+}
+
+# Return 1 if the target supports vectors of 256 bits.
+
+proc check_effective_target_vect256 { } {
+    return [expr { [lsearch -exact [available_vector_sizes] 256] >= 0 }]
+}
+
+# Return 1 if the target supports vectors of 128 bits.
+
+proc check_effective_target_vect128 { } {
+    return [expr { [lsearch -exact [available_vector_sizes] 128] >= 0 }]
+}
+
 # Return 1 if the target supports vectors of 64 bits.
 
 proc check_effective_target_vect64 { } {