[Bug testsuite/51251] conflicting -mcpu switches during testing

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51251

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|target                      |testsuite
            Summary|SPARC _64 instructions in   |conflicting -mcpu switches
                   |V7 executables              |during testing

--- Comment #7 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-11-21 12:43:45 UTC ---
> The board in question is really a V7 and that is the proper cpu selection. It
> is added by the test framework in a dejagnu board file.

OK, but adding it like so is wrong.  Suppose that a SPARC-specific test checks
that some feature available only in V8 works; by adding -mcpu=cypress without
further ado, you'll most likely make the test fail.

Overriding compiler switches in tests is a no-no and...

> The issue is that when running on real hardware, you can't use arbitrary cpu
> flags and expect it to work.  And it is wrong to say xfail on sparc-rtems
> because they could work on another board running rtems. Just not this one.

...yes, that's why we have the dg-require-effective-target framework now.