Hi,

This should be resolved by following commit that I have just pushed: commit 5513935f48e50e97c854b746e758842c846a7740 Author: Tomasz Kamiński tkaminsk@redhat.com 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 ci_notify@linaro.org 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 tkaminsk@redhat.com | 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 linaro-toolchain@lists.linaro.org mailing list.

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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/ar... 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/ar... The list of [ignored] baseline and flaky failures are in

https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2498/ar...

Current build : https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2498/ar... Reference build : https://ci.linaro.org/job/tcwg_gnu_cross_check_gcc--master-arm-build/2497/ar...

Instruction to reproduce the build : https://gitlab.com/LinaroLtd/tcwg/ci/interesting-commits/-/raw/master/gcc/sh...

Full commit : See in git+ssh://linaroci@gcc.gnu.org/git/gcc.git