[Bug testsuite/65116] New: additional_sources not defined anymore during dg-final

["vries at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65116

            Bug ID: 65116
           Summary: additional_sources not defined anymore during dg-final
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org

When running vect-simd-clone-10.c, a file vect-simd-clone-10a.c.126t.vect is
left in the test directory.

The testcase lists vect-simd-clone-10a.c as addditional source:
...
/* { dg-additional-sources vect-simd-clone-10a.c } */
...

Then the test-case cleans up the respective tree-dump:
...
/* { dg-final { cleanup-tree-dump "vect" } } */
...

The cleanup-tree-dump calls cleanup-dump, which intends to take
additional_sources into account.

However, the global additional_sources declaration is missing, so the exists
additional_sources will always return false.

And if we add the global additional_sources declaration, it still fails,
because additional_sources is empty. It has been reset by
dg-additional-files-options, which is called by gcc_target_compile, which is
called by gcc-dg-test-1, which is called by gcc-dg-test, which is called by
dg-test as ${tool}-dg-test.

dg-test does the the dg-final-code processing after the ${tool}-dg-test so at
that point additional_sources is empty.