[U-Boot] [PATCH 1/2] armv8: apply -mgeneral-regs-only

[Peng Fan <peng.fan@nxp.com>]

> -----Original Message-----
> From: Tom Rini [mailto:trini at konsulko.com]
> Sent: Wednesday, July 05, 2017 3:38 AM
> To: Dr. Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
> Cc: Peng Fan <peng.fan@nxp.com>; u-boot at lists.denx.de
> Subject: Re: [U-Boot] [PATCH 1/2] armv8: apply -mgeneral-regs-only
> 
> On Tue, Jul 04, 2017 at 06:38:10PM +0200, Dr. Philipp Tomsich wrote:
> > Tom,
> >
> > Please note that some GCC versions had a code-generation bug when
> > -mgeneral-regs-only was used (we hit this for a customer in a vendor
> > GCC we maintain):
> > 	https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64304
> >
> > Until everyone upgrades to a recently recent GCC (or until UBoot
> > enforces this next January), some people may hit hard-to-reproduce
> > issues.
> >
> > A better way to suppress SIMD generation would be to use:
> > 	-march=armv8-a+nosimd
> 
> Ah, good to know.  Peng, please re-spin.

According to https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html,
There is no +nosimd for armv8-a. I also tried +nosimd,
There is still "str     q0, [x29,#112] ".  If I use armv8-a+nofp, there is no
such instructions. Then, do you agree using " armv8-a+nofp "?

Thanks,
Peng.

> 
> >
> > Regards,
> > Philipp.
> >
> > > On 04 Jul 2017, at 15:32, Tom Rini <trini@konsulko.com> wrote:
> > >
> > > On Mon, Jul 03, 2017 at 09:14:07PM +0800, Peng Fan wrote:
> > >
> > >> Pass -mgeneral-regs-only to GCC, if not compiler may generate
> > >> instructions that use SIMD registers.
> > >>
> > >> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > >> Cc: Albert Aribaud <albert.u.boot@aribaud.net>
> > >> Cc: Tom Rini <trini@konsulko.com>
> > >
> > > Reviewed-by: Tom Rini <trini@konsulko.com>
> > >
> > > --
> > > Tom
> > > _______________________________________________
> > > U-Boot mailing list
> > > U-Boot at lists.denx.de
> > > https://lists.denx.de/listinfo/u-boot
> >
> 
> --
> Tom