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

[Ramana Radhakrishnan]

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.preudho...@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.preudho...@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.preudho...@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.preudho...@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.preudho...@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