Re: [PATCH, GCC/ARM, Stage 1] Rename FPSCR builtins to correct names

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

Hi Christophe,

On 23/06/17 20:10, Christophe Lyon wrote:
> Hi Thomas,
>
> On 23 June 2017 at 17:48, Thomas Preudhomme
> <thomas.preudhomme@foss.arm.com> wrote:
> > Hi Kyrill,
> >
> >
> > On 10/04/17 15:01, Kyrill Tkachov wrote:
> > > Hi Prakhar,
> > > Sorry for the delay,
> > >
> > > On 22/03/17 10:46, Prakhar Bahuguna wrote:
> > > > The GCC documentation in section 6.60.8 ARM Floating Point Status and
> > > > Control
> > > > Intrinsics states that the FPSCR register can be read and written to
> > > > using the
> > > > intrinsics __builtin_arm_get_fpscr and __builtin_arm_set_fpscr. However,
> > > > these
> > > > are misnamed within GCC itself and these intrinsic names are not
> > > > recognised.
> > > > This patch corrects the intrinsic names to match the documentation, and
> > > > adds
> > > > tests to verify these intrinsics generate the correct instructions.
> > > >
> > > > Testing done: Ran regression tests on arm-none-eabi for Cortex-M4.
> > > >
> > > > 2017-03-09  Prakhar Bahuguna  <prakhar.bahuguna@arm.com>
> > > >
> > > > gcc/ChangeLog:
> > > >
> > > >      * gcc/config/arm/arm-builtins.c (arm_init_builtins): Rename
> > > >        __builtin_arm_ldfscr to __builtin_arm_get_fpscr, and rename
> > > >        __builtin_arm_stfscr to __builtin_arm_set_fpscr.
> > > >      * gcc/testsuite/gcc.target/arm/fpscr.c: New file.
> > > >
> > > > Okay for stage 1?
> > >
> > >
> > > I see that the mistake was in not addressing one of the review comments
> > > in:
> > > https://gcc.gnu.org/ml/gcc-patches/2014-04/msg01832.html
> > > properly in the patch that added these functions :(
> > >
> > > This is ok for stage 1 if a bootstrap and test on arm-none-linux-gnueabihf
> > > works
> > > fine
> > > I don't think we want to maintain the __builtin_arm_[ld,st]fscr names for
> > > backwards compatibility
> > > as they were not documented and are __builtin_arm* functions that we don't
> > > guarantee to maintain.
> >
> >
> > How about a backport to GCC 5, 6 & 7? The patch applied cleanly on each of
> > these versions and the testsuite didn't show any regression for any of the
> > backport when run for Cortex-M7.
>
> Three's a problem with GCC-5:
>      gcc.target/arm/fpscr.c: unknown effective target keyword
> `arm_fp_ok' for " dg-require-effective-target 4 arm_fp_ok "
>
> Indeed arm_fp_ok effective-target does not exist in the gcc-5 branch.

Oh no. I remember not seeing anything but I can indeed see this with 
compare_tests from the sum file I save after each testing. Alright, what is done 
is done, working on a patch now.

Best regards,

Thomas