[testsuite][arm] Fix cmse-15.c expected output

[Richard Sandiford]

Christophe Lyon <christophe.lyon@linaro.org> writes:
> On Wed, 8 Apr 2020 at 11:48, Richard Sandiford
> <richard.sandiford@arm.com> wrote:
>>
>> Christophe Lyon via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
>> > Hi,
>> >
>> > While checking Martin's fix for PR ipa/94445, he made me realize that
>> > the cmse-15.c testcase still fails at -Os because ICF means that we
>> > generate
>> > nonsecure2:
>> >         b       nonsecure0
>> >
>> > which is OK, but does not match the currently expected
>> > nonsecure2:
>> > ...
>> >         bl      __gnu_cmse_nonsecure_call
>> >
>> > (see https://gcc.gnu.org/pipermail/gcc-patches/2020-April/543190.html)
>> >
>> > The test has already different expectations for v8-M and v8.1-M.
>> >
>> > I've decided to try to use check-function-bodies to account for the
>> > different possibilities:
>> > - v8-M vs v8.1-M via two different prefixes
>> > - code generation variants (-0?) via multiple regexps
>> >
>> > I've tested that the test now passes with --target-board=-march=armv8-m.main
>> > and --target-board=-march=armv8.1-m.main.
>> >
>> > I feel this a bit too much of a burden for the purpose, maybe there's
>> > a better way of handling all these alternatives (in particular,
>> > there's a lot of duplication since the expected code for the secure*
>> > functions is the same for v8-M and v8.1-M).
>>
>> FWIW, an alternative is to give multiple versions with the same prefix
>> and use { target ... } to select between them.  E.g.:
>>
>> /*
>> ** foo:   { target a }
>> **      ...
>> */
>> /*
>> ** foo:   { target { ! a } }
>> **      ...
>> */
>>
>
> Ha indeed, that makes it simpler. Thanks for the example, I hadn't
> fully understand how to use that scheme: I tried to add a third
> alternative (different prefix) with no selector for cases where no
> distinction was needed, but I realized that all alternatives need
> their full matching description.
>
> However, {target { ! a } } does not work as is, so the attached patch
> uses a non-greedy regexp to avoid trying "! a }" instead of "target {
> ! a }"

Oops.  This part is definitely OK, thanks.

> If OK, maybe I should commit that as two separate patches?

I don't really feel qualified to review the substance of the arm part
of the patch, but given Andre's LGTM for that in the earlier version,
a rubber-stamp OK for that too.  I agree separate commits might be
better.

Thanks,
Richard