diff --git a/gcc/testsuite/gfortran.dg/submodule_8.f08 b/gcc/testsuite/gfortran.dg/submodule_8.f08
new file mode 100644
index 00000000000..15a38a58833
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/submodule_8.f08
@@ -0,0 +1,44 @@
+! { dg-do run }
+!
+! Checks that F2008:11.2.3 para 2 is correctly implemented so that
+! no error results from using 'mod_s' for both a module name and
+! a submodule name. The submodule is now identified as 'mod_a.mod_s'
+! internally and the submodule file as 'mod_a@mod_s.smod'.
+!
+! Contributed by Reinhold Bader  <reinhold.bader@lrz.de>
+!
+module mod_a
+  implicit none
+  interface
+    module subroutine p()
+    end subroutine
+  end interface
+end module
+
+submodule (mod_a) mod_s
+  implicit none
+  integer :: i=-2
+contains
+  module procedure p
+    if (i .ne. -2) then
+      call abort
+    end if
+  end procedure
+end submodule
+
+module mod_s
+  use mod_a
+  implicit none
+  integer :: i=2
+end module
+
+program a_s
+  use mod_s
+  implicit none
+  if (i==2) then
+    call p()
+  else
+    call abort
+  end if
+end program
+! { dg-final { cleanup-submodules "mod_a@mod_s" } }
diff --git a/gcc/testsuite/gfortran.dg/submodule_9.f08 b/gcc/testsuite/gfortran.dg/submodule_9.f08
new file mode 100644
index 00000000000..4589ebcd6d2
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/submodule_9.f08
@@ -0,0 +1,40 @@
+! { dg-do compile }
+!
+! Checks that the name clash between the two submodules 'mod_s' is an error.
+!
+! Contributed by Reinhold Bader  <reinhold.bader@lrz.de>
+!
+module mod_a
+  implicit none
+  interface
+    module subroutine p()
+    end subroutine
+  end interface
+end module
+
+submodule (mod_a) mod_s ! { dg-error "already being used as a MODULE" }
+end submodule
+
+submodule (mod_a:mod_s) b
+end submodule
+
+submodule (mod_a:b) mod_s ! { dg-error "already being used as a MODULE" }
+  implicit none
+  integer :: i=-2
+contains
+  module procedure p
+    write(*,*) 'FAIL'
+  end procedure
+end submodule
+
+module mod_s
+  use mod_a
+  implicit none
+  integer :: i=2
+end module
+
+program a_s
+  use mod_s
+  implicit none
+  call p()
+end program