1 files changed, 66 insertions, 0 deletions
diff --git a/gcc/testsuite/gfortran.dg/dec_union_1.f90 b/gcc/testsuite/gfortran.dg/dec_union_1.f90
new file mode 100644
index 00000000000..36af53adfe1
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dec_union_1.f90
@@ -0,0 +1,66 @@
+! { dg-do run }
+! { dg-options "-fdec-structure" }
+!
+! Test whether union backend declarations are corrently _not_ copied when they
+! are not in fact equal. The structure defined in sub() is seen later, but
+! where siz has a different value.
+!
+
+subroutine aborts (s)
+  character(*), intent(in) :: s
+  print *, s
+  call abort()
+end subroutine
+
+subroutine sub ()
+  integer, parameter :: siz = 1024
+  structure /s6/
+    union ! U0
+      map ! M0
+        integer ibuf(siz)
+      end map
+      map ! M1
+        character(8) cbuf(siz)
+      end map
+      map ! M2
+        real rbuf(siz)
+      end map
+    end union
+  end structure
+  record /s6/ r6
+  r6.ibuf(1) = z'badbeef'
+  r6.ibuf(2) = z'badbeef'
+end subroutine
+
+! Repeat definition from subroutine sub with different size parameter.
+! If the structure definition is copied here the stack may get messed up.
+integer, parameter :: siz = 65536
+structure /s6/
+  union ! U12
+    map
+      integer ibuf(siz)
+    end map
+    map
+      character(8) cbuf(siz)
+    end map
+    map
+      real rbuf(siz)
+    end map
+  end union
+end structure
+
+record /s6/ r6
+integer :: r6_canary = 0
+
+! Copied type declaration - this should not cause problems
+i = 1
+do while (i < siz)
+  r6.ibuf(i) = z'badbeef'
+  i = i + 1
+end do
+
+if ( r6_canary .ne. 0 ) then
+  call aborts ('copied decls: overflow')
+endif
+
+end