[Bug fortran/31119] -fbounds-check: Check for presence of optional arguments before bound checking

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31119

Mikael Morin <mikael at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |mikael at gcc dot gnu.org

--- Comment #10 from Mikael Morin <mikael at gcc dot gnu.org> 2012-10-21 13:52:35 UTC ---
(In reply to comment #8)
> Actually, the situation is a bit bizarre. There are no conforming programs for
> which bounds-checking can trigger... all these bounds-checking statements can
> be just optimized away :-). That's not quite what the users want...

Well, if the middle-end is able to prove that the bounds checking code is
useless, it may as well remove it.  In the case of a bogus array access, that
code is useful, so the middle-end shouldn't be able to prove that it isn't, and
the it won't be removed.
For the other case (code removed where it should stay) there is a bug in the
compiler, but that's not what -fbounds-check is supposed to check ;-).


Regarding the initial question:
> Hi,
> can someone fortran aware please double-check that the tests
> 
>     * gfortran.dg/bounds_check_9.f90: New test.
>     * gfortran.dg/bounds_check_fail_2.f90: New test.
> 
> do not contain out of bounds access?

There should be none, as the -fbounds-check instrumentation is supposed to
catch out of bounds early enough, so that the code is valid from a middle-end
point of view.