Re: [Linaro-TCWG-CI] gcc-16-6301-gb3c167b61fd7: 4 regressions on arm

Hi,

This should be resolved by following commit that I have just pushed:
commit 5513935f48e50e97c854b746e758842c846a7740
Author: Tomasz Kamiński <[email protected]>
Date:   Wed Jan 7 17:24:55 2026 +0100

    libstdc++: Use tree-dump-gimple in variant constant init tests.

    Use of scan-assembler-dem for matching against debug symbols, turned
out to not
    be portable, as they representation in assembly output differs between
platforms:
    arm use 60 columns limit, emitting multiple rows, and some platforms
may encode
    them using base64.

    We use tree-dump-gimple instead, that outputs a constructor name
portably,
    allowing us to simply match for invocation of constructor for given
type, as each
    variable has different type.

    To use scan-tree-dump(-not) we load scantree.exp file and it's
dependency
    scandump.exp from gcc/testsuite/lib.

    libstdc++-v3/ChangeLog:

            * testsuite/20_util/variant/constinit.cc: Use scan-tree-dump
            for matching of constructor.
            * testsuite/20_util/variant/constinit_compat.cc: Likewise.
            * testsuite/lib/libstdc++.exp: Load scantree.exp and
scandump.exp.

Regards,
Tomasz

On Thu, Dec 25, 2025 at 8:42 AM <[email protected]> wrote:

> Dear contributor,
>
> Our automatic CI has detected problems related to your patch(es). Please
> find some details below.
>
> In  master-arm, after:
>   | commit gcc-16-6301-gb3c167b61fd7
>   | Author: Tomasz Kamiński <[email protected]>
>   | Date:   Thu Dec 11 10:43:44 2025 +0100
>   |
>   |     libstdc++: Use union to store non-trivially destructible types in
> C++17 mode [PR112591]
>   |
>   |     This patch disables use of specialization _Uninitialized<_Type,
> false> for
>   |     non-trivially destructible types by default in C++17, and
> fallbacks to
>   |     the  primary template, that stores the type in union directly.
> This makes the
>   | ... 39 lines of the commit log omitted.
>
> Produces 4 regressions:
>   |
>   | regressions.sum:
>   | Running libstdc++:libstdc++-dg/conformance.exp ...
>   | FAIL: 20_util/variant/constinit.cc -std=gnu++20  scan-assembler-dem
> (std::in_place_index_t<1ul?>, double&&)
>   | FAIL: 20_util/variant/constinit.cc -std=gnu++20  scan-assembler-dem
> (std::in_place_index_t<1ul?>, int&&)
>   | FAIL: 20_util/variant/constinit_compat.cc -std=gnu++20
> scan-assembler-dem (std::in_place_index_t<1ul?>, double&&)
>   | FAIL: 20_util/variant/constinit_compat.cc -std=gnu++20
> scan-assembler-dem (std::in_place_index_t<1ul?>, int&&)
>
> Used configuration :
>  *CI config* tcwg_gnu_cross_check_gcc master-arm
>  *configure and test flags:* --target arm-linux-gnueabihf
>
> We track this bug report under
> https://linaro.atlassian.net/browse/GNU-1793. Please let us know if you
> have a fix.
>
> If you have any questions regarding this report, please ask on
> [email protected] mailing list.
>
>
> -----------------8<--------------------------8<--------------------------8<--------------------------
>
> The information below contains the details of the failures, and the ways
> to reproduce a debug environment:
>
> You can find the failure logs in *.log.1.xz files in
>  *
> https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2498/artifact/artifacts/00-sumfiles/
> The full lists of regressions and improvements as well as configure and
> make commands are in
>  *
> https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2498/artifact/artifacts/notify/
> The list of [ignored] baseline and flaky failures are in
>  *
> https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2498/artifact/artifacts/sumfiles/xfails.xfail
>
> Current build   :
> https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2498/artifact/artifacts
> Reference build :
> https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2497/artifact/artifacts
>
> Instruction to reproduce the build :
> https://gitlab.com/LinaroLtd/tcwg/ci/interesting-commits/-/raw/master/gcc/sha1/b3c167b61fd75fe9820636d9f7fff7920ca9b084/tcwg_gnu_cross_check_gcc/master-arm/reproduction_instructions.txt
>
> Full commit : See in git+ssh://[email protected]/git/gcc.git