Re: %fs and %gs segments on x86/x86-64

["Bin.Cheng" <amker dot cheng at gmail dot com>]

On Thu, Jul 9, 2015 at 8:02 PM, Armin Rigo <arigo@tunes.org> wrote:
> Hi all,
>
> Here is an updated patch (attached) for __seg_fs and __seg_gs:
>
> * added a target hook "default_pointer_address_modes" to avoid
> disabling a few gcc optimizations which, according to my reading of
> the documentation, should continue to work even in the presence of
> multiple address spaces as long as they all use the same mode for
> pointers.
>
> * account for the extra byte in "%gs:(...)" addresses.
>
> * added one test case (better than none!) using "scan-assembler".  If
> people agree that this is the style of test that we need here, then I
> could add more of them.
>
> The diff is against trunk.  The tests don't all pass; the failures
> really seem unrelated, but I guess I should grab the same revision
> without the patch, compile it, try to run all the tests on the same
> machine, and compare the list of failures... it just takes a serious
> amount of time to do so...
>
> I also reported the bug I got previously
> (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66768) and it seems to
> occur already in other targets with address spaces.
For this issue, I will work out a patch for it.

Thanks,
bin
>
>
> A bientÃt,
>
> Armin.