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Re: [RS6000] Fix PR45053


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 ;)

Richard.

> --
> Alan Modra
> Australia Development Lab, IBM


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