This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [RS6000] Fix PR45053
On Feb 7, 2013, at 3:49 AM, Richard Biener <richard.guenther@gmail.com> wrote:
> On Thu, Feb 7, 2013 at 11:51 AM, Alan Modra <amodra@gmail.com> wrote:
>> On Thu, Feb 07, 2013 at 10:11:02AM +0100, Richard Biener wrote:
>>> On Thu, Feb 7, 2013 at 9:45 AM, Alan Modra <amodra@gmail.com> wrote:
>>>> I think this one counts as obvious, but I'll ask for permission anyway.
>>>> Bootstrapped etc. powerpc-linux. OK everywhere?
>>>
>>> Isn't there a way to just disable the out-of-line register save/restore
>>> functions? Adding -O2 looks odd.
>>
>> There isn't. See rs6000.c:rs6000_savres_strategy. I should note too
>> that using -O2 (anything but -Os) is only a solution for powerpc ELF.
>> powerpc-darwin may not be susceptible to the bug, but if it is then
>> some changes will be needed in rs6000_savres_strategy. AIX doesn't
>> have a problem here since it always uses inline gpr saves/restores.
>>
>> Also, powerpc64 targets using GNU ld or gold don't have a problem with
>> crtend.o calling save/restore functions as the linker creates these
>> functions.
>
> It should be possible to add a -msavres-inline switch, right? The other
> option would be to have a -Ono-s option that turns -Os into -O2
> (optimize == 2 for both) but leaves -O1/-O0 alone (by basically just
> setting optimize_size to 0). Of course I consider that more ugly than
> a new switch to explicitely disable non-inline saveres code ;)
I like the -O2 approach as a permanent solution… Having flags adds a burden to everyone and should be discouraged in all but the most dire of cases. This isn't dire enough.