[PATCH 2/2] [ARM] Add support for -mpure-code in thumb-1 (v6m)

[Christophe Lyon]

On Mon, 13 Jan 2020 at 14:49, Kyrill Tkachov
<kyrylo.tkachov@foss.arm.com> wrote:
>
> Hi Christophe,
>
> On 12/17/19 3:31 PM, Kyrill Tkachov wrote:
> >
> > On 12/17/19 2:33 PM, Christophe Lyon wrote:
> >> On Tue, 17 Dec 2019 at 11:34, Kyrill Tkachov
> >> <kyrylo.tkachov@foss.arm.com> wrote:
> >>> Hi Christophe,
> >>>
> >>> On 11/18/19 9:00 AM, Christophe Lyon wrote:
> >>>> On Wed, 13 Nov 2019 at 15:46, Christophe Lyon
> >>>> <christophe.lyon@linaro.org> wrote:
> >>>>> On Tue, 12 Nov 2019 at 12:13, Richard Earnshaw (lists)
> >>>>> <Richard.Earnshaw@arm.com> wrote:
> >>>>>> On 18/10/2019 14:18, Christophe Lyon wrote:
> >>>>>>> +      bool not_supported = arm_arch_notm || flag_pic ||
> >>>> TARGET_NEON;
> >>>>>> This is a poor name in the context of the function as a whole.
> >>>>>> What's
> >>>>>> not supported.  Please think of a better name so that I have some
> >>>>>> idea
> >>>>>> what the intention is.
> >>>>> That's to keep most of the code common when checking if -mpure-code
> >>>>> and -mslow-flash-data are supported.
> >>>>> These 3 cases are common to the two compilation flags, and
> >>>>> -mslow-flash-data still needs to check TARGET_HAVE_MOVT in addition.
> >>>>>
> >>>>> Would "common_unsupported_modes" work better for you?
> >>>>> Or I can duplicate the "arm_arch_notm || flag_pic || TARGET_NEON" in
> >>>>> the two tests.
> >>>>>
> >>>> Hi,
> >>>>
> >>>> Here is an updated version, using "common_unsupported_modes" instead
> >>>> of "not_supported", and fixing the typo reported by Kyrill.
> >>>> The ChangeLog is still the same.
> >>>>
> >>>> OK?
> >>>
> >>> The name looks ok to me. Richard had a concern about Armv8-M Baseline,
> >>> but I do see it being supported as you pointed out.
> >>>
> >>> So I believe all the concerns are addressed.
> >> OK, thanks!
> >>
> >>> Thus the code is ok. However, please also updated the documentation for
> >>> -mpure-code in invoke.texi (it currently states that a MOVT instruction
> >>> is needed).
> >>>
> >> I didn't think about this :(
> >> It currently says: "This option is only available when generating
> >> non-pic code for M-profile targets with the MOVT instruction."
> >>
> >> I suggest to remove the "with the MOVT instruction" part. Is that OK
> >> if I commit my patch and this doc change?
> >
> > Yes, I think that is simplest correct change to make.
> >
>
> Can you also send a patch to the changes.html page for GCC 10 making
> users aware that this restriction is now lifted?
>

Sure. I should have thought of it when I submitted the GCC patch...

How about the attached? I'm not sure about the right upper/lower case
and <code> markers....

Thanks,

Christophe

> Thanks,
>
> Kyrill
>
>
> > Thanks,
> >
> > Kyrill
> >
> >
> >> Christophe
> >>
> >>> Thanks,
> >>>
> >>> Kyrill
> >>>
> >>>
> >>>
> >>>> Thanks,
> >>>>
> >>>> Christophe
> >>>>
> >>>>> Thanks,
> >>>>>
> >>>>> Christophe
> >>>>>
> >>>>>> R.
-------------- next part --------------
commit ba2a354c9ed6c75ec00bf21dd6938b89a113a96e
Author: Christophe Lyon <christophe.lyon@linaro.org>
Date:   Tue Jan 14 13:48:19 2020 +0000

    [arm] Document -mpure-code support for v6m in gcc-10

diff --git a/htdocs/gcc-10/changes.html b/htdocs/gcc-10/changes.html
index caa9df7..26cdf66 100644
--- a/htdocs/gcc-10/changes.html
+++ b/htdocs/gcc-10/changes.html
@@ -417,7 +417,11 @@ a work-in-progress.</p>
   data-processing intrinsics</a> to include 32-bit SIMD, saturating arithmetic,
   16-bit multiplication and other related intrinsics aimed at DSP algorithm
   optimization.
-   </li>
+  </li>
+  <li>Support for <code>-mpure-code</code> in Thumb-1 (v6m) has been
+  added: this M-profile feature is no longer restricted to targets
+  with <code>MOTV</code>. For instance, Cortex-M0 is now
+  supported</li>
 </ul>
 
 <h3 id="avr">AVR</h3>