Re: [PATCH, GCC/ARM, gcc-5-branch] Fix PR80082: LDRD erronously used for 64bit load on ARMv7-R

[Ramana Radhakrishnan <ramana dot radhakrishnan at foss dot arm dot com>]

On 10/04/17 13:12, Thomas Preudhomme wrote:
> Hi,
>
> Currently GCC is happy to use LDRD to perform a 64bit load on ARMv7-R,
> as shown by the testcase on this patch. However, LDRD is only atomic
> when LPAE extensions is available, which they are not for ARMv7-R. This
> commit solve the issue by introducing a new feature bit to distinguish
> LPAE extensions instead of deducing it from div instruction
> availability.
>
> ChangeLog entries are as follow:
>
> *** gcc/ChangeLog ***
>
> 2017-03-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>
>     PR target/80082
>     * config/arm/arm-protos.h (FL_LPAE): Define macro.
>     (FL_FOR_ARCH7VE): Add FL_LPAE.
>     (arm_arch_lpae): Declare extern.
>     * config/arm/arm.c (arm_arch_lpae): Declare.
>     (arm_option_override): Define arm_arch_lpae.
>     * config/arm/arm.h (TARGET_HAVE_LPAE): Redefine in term of
>     arm_arch_lpae.
>
> *** gcc/testsuite/ChangeLog ***
>
> 2017-03-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>
>     PR target/80082
>     * gcc.target/arm/atomic_loaddi_10.c: New testcase.
>     * gcc.target/arm/atomic_loaddi_11.c: Likewise.
>
> Is this ok for gcc-5-branch?

OK.

Ramana

> Best regards,
>
> Thomas
>
> On 06/04/17 14:05, Ramana Radhakrishnan wrote:
> > On Mon, Mar 27, 2017 at 12:15 PM, Thomas Preudhomme
> > <thomas.preudhomme@foss.arm.com> wrote:
> > > Hi,
> > >
> > > Currently GCC is happy to use LDRD to perform a 64bit load on ARMv7-R,
> > > as shown by the testcase on this patch. However, LDRD is only atomic
> > > when LPAE extensions is available, which they are not for ARMv7-R. This
> > > commit solve the issue by introducing a new feature bit to distinguish
> > > LPAE extensions instead of deducing it from div instruction
> > > availability.
> >
> >
> > Ok but with the testsuite fix that I just approved,  please also fix
> > in gcc-5 branch.
> >
> > Thanks,
> > Ramana
> >
> > > ChangeLog entries are as follow:
> > >
> > > *** gcc/ChangeLog ***
> > >
> > > 2017-03-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
> > >
> > >         PR target/80082
> > >         * config/arm/arm-protos.h (FL_LPAE): Define macro.
> > >         (FL_FOR_ARCH7VE): Add FL_LPAE.
> > >         (arm_arch_lpae): Declare extern.
> > >         * config/arm/arm.c (arm_arch_lpae): Declare.
> > >         (arm_option_override): Define arm_arch_lpae.
> > >         * config/arm/arm.h (TARGET_HAVE_LPAE): Redefine in term of
> > >         arm_arch_lpae.
> > >
> > > *** gcc/testsuite/ChangeLog ***
> > >
> > > 2017-03-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
> > >
> > >         PR target/80082
> > >         * gcc.target/arm/atomic_loaddi_10.c: New testcase.
> > >         * gcc.target/arm/atomic_loaddi_11.c: Likewise.
> > >
> > >
> > > Testing: bootstrapped for -march=armv7ve and testsuite shows no
> > > regression.
> > >
> > > Is this ok for gcc-6-branch?
> > >
> > > Best regards,
> > >
> > > Thomas