Re: [PATCH, GCC/ARM] Fix PR77904: callee-saved register trashed when clobbering sp

[Thomas Preudhomme <thomas dot preudhomme at foss dot arm dot com>]

On 17/11/16 09:11, Kyrill Tkachov wrote:
> On 17/11/16 08:56, Thomas Preudhomme wrote:
> > On 16/11/16 10:30, Kyrill Tkachov wrote:
> > > Hi Thomas,
> > >
> > > On 03/11/16 16:52, Thomas Preudhomme wrote:
> > > > Hi,
> > > >
> > > > When using a callee-saved register to save the frame pointer the Thumb-1
> > > > prologue fails to save the callee-saved register before that. For ARM and
> > > > Thumb-2 targets the frame pointer is handled as a special case but nothing is
> > > > done for Thumb-1 targets. This patch adds the same logic for Thumb-1 targets.
> > > >
> > > > ChangeLog entries are as follow:
> > > >
> > > > *** gcc/ChangeLog ***
> > > >
> > > > 2016-11-02  Thomas Preud'homme <thomas.preudhomme@arm.com>
> > > >
> > > >         PR target/77904
> > > >         * config/arm/arm.c (thumb1_compute_save_reg_mask): mark frame pointer
> > > >         in save register mask if it is needed.
> > >
> > > s/mark/Mark/
> > >
> > > > *** gcc/testsuite/ChangeLog ***
> > > >
> > > > 2016-11-02  Thomas Preud'homme <thomas.preudhomme@arm.com>
> > > >
> > > >         PR target/77904
> > > >         * gcc.target/arm/pr77904.c: New test.
> > > >
> > > >
> > > > Testing: Testsuite shows no regression when run with arm-none-eabi GCC
> > > > cross-compiler for Cortex-M0 target.
> > > >
> > > > Is this ok for trunk?
> > >
> > > I'd ask for a bootstrap, but this code is Thumb-1 only so it wouldn't affect
> > > anything.
> >
> > I can bootstrap for armv4t with --with-mode=thumb which would at least
> > exercise the path. I'll try such a bootstrap on qemu.
>
> If you can get it to work, then yes please.

Bootstrap came back clean so I've committed the patch (r242693). Thanks!

Best regards,

Thomas