Re: [Linaro-TCWG-CI] gcc-16-3649-gc440b585ba3: 4 regressions on master-thumb_m3_softfp_eabi
I'd like to apologize for causing these regressions. Below I've copied out the relevant parts from the logs. To me it looks like _Xv is a reserved identifier.
I'll prepare a patch to fix the issue.
On 9/9/25 6:54 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 arm-eabi cortex-m3 softfp, after: | commit gcc-16-3649-gc440b585ba3 | Author: Luc Grosheintz luc.grosheintz@gmail.com | Date: Thu Sep 4 14:20:28 2025 +0200 | | libstdc++: Implement constant_wrapper, cw from P2781R9. | | This is a partial implementation of P2781R9. It adds std::cw and | std::constant_wrapper, but doesn't modify __integral_constant_like for | span/mdspan. | ... 25 lines of the commit log omitted.
Produces 4 regressions: | | regressions.sum: | Running g++:g++.old-deja/old-deja.exp ... | FAIL: g++.old-deja/g++.robertl/eb39.C -std=c++26 (test for excess errors)
Code: 4651: template<_CwFixedValue _Xv, typename> 4652: struct constant_wrapper : _CwOperators 4653: {
Compiler error: /home/tcwg-buildslave/workspace/tcwg_gnu_0/abe/builds/x86_64-pc-linux-gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include/type_traits:4651:26: error: expected '>' before numeric constant
My guess is that _Xv is a reserved name. It's not on the list of common bad identifiers [1], but it's the only guess I have.
[1]: https://gcc.gnu.org/onlinedocs/libstdc++/manual/source_code_style.html
| FAIL: g++.old-deja/g++.robertl/eb54.C -std=c++26 (test for excess errors)
Same as above.
| UNRESOLVED: g++.old-deja/g++.robertl/eb54.C -std=c++26 compilation failed to produce executable
Same as above.
| FAIL: g++.old-deja/g++.warn/iomanip.C -std=gnu++26 (test for excess errors)
Same as above.
Used configuration : *CI config* tcwg_gnu_embed_check_gcc arm-eabi -mthumb -march=armv7-m -mtune=cortex-m3 -mfloat-abi=softfp -mfpu=auto *configure and test flags:* --target arm-eabi --disable-multilib --with-mode=thumb --with-cpu=cortex-m3 --with-float=softfp --target_board=-mthumb/-march=armv7-m/-mtune=cortex-m3/-mfloat-abi=softfp/-mfpu=auto qemu_cpu=cortex-m3
We track this bug report under https://linaro.atlassian.net/browse/GNU-1676. 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
The full lists of regressions and improvements as well as configure and make commands are in
The list of [ignored] baseline and flaky failures are in
Current build : https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc--master-thumb_m3_softfp_e... Reference build : https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc--master-thumb_m3_softfp_e...
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
Jonathan Wakely already fixed it. Please ignore the rest.
On 9/9/25 11:16 AM, Luc Grosheintz wrote:
I'd like to apologize for causing these regressions. Below I've copied out the relevant parts from the logs. To me it looks like _Xv is a reserved identifier.
I'll prepare a patch to fix the issue.
On 9/9/25 6:54 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 arm-eabi cortex-m3 softfp, after: | commit gcc-16-3649-gc440b585ba3 | Author: Luc Grosheintz luc.grosheintz@gmail.com | Date: Thu Sep 4 14:20:28 2025 +0200 | | libstdc++: Implement constant_wrapper, cw from P2781R9. | | This is a partial implementation of P2781R9. It adds std::cw and | std::constant_wrapper, but doesn't modify __integral_constant_like for | span/mdspan. | ... 25 lines of the commit log omitted.
Produces 4 regressions: | | regressions.sum: | Running g++:g++.old-deja/old-deja.exp ... | FAIL: g++.old-deja/g++.robertl/eb39.C -std=c++26 (test for excess errors)
Code: 4651: template<_CwFixedValue _Xv, typename> 4652: struct constant_wrapper : _CwOperators 4653: {
Compiler error: /home/tcwg-buildslave/workspace/tcwg_gnu_0/abe/builds/x86_64-pc-linux- gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include/ type_traits:4651:26: error: expected '>' before numeric constant
My guess is that _Xv is a reserved name. It's not on the list of common bad identifiers [1], but it's the only guess I have.
| FAIL: g++.old-deja/g++.robertl/eb54.C -std=c++26 (test for excess errors)
Same as above.
| UNRESOLVED: g++.old-deja/g++.robertl/eb54.C -std=c++26 compilation failed to produce executable
Same as above.
| FAIL: g++.old-deja/g++.warn/iomanip.C -std=gnu++26 (test for excess errors)
Same as above.
Used configuration : *CI config* tcwg_gnu_embed_check_gcc arm-eabi -mthumb -march=armv7-m -mtune=cortex-m3 -mfloat-abi=softfp -mfpu=auto *configure and test flags:* --target arm-eabi --disable-multilib -- with-mode=thumb --with-cpu=cortex-m3 --with-float=softfp -- target_board=-mthumb/-march=armv7-m/-mtune=cortex-m3/-mfloat- abi=softfp/-mfpu=auto qemu_cpu=cortex-m3
We track this bug report under https://linaro.atlassian.net/browse/ GNU-1676. 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.
-----------------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_embed_check_gcc--master- thumb_m3_softfp_eabi-build/518/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_embed_check_gcc--master- thumb_m3_softfp_eabi-build/518/artifact/artifacts/notify/ The list of [ignored] baseline and flaky failures are in * https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc--master- thumb_m3_softfp_eabi-build/518/artifact/artifacts/sumfiles/xfails.xfail
Current build : https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc-- master-thumb_m3_softfp_eabi-build/518/artifact/artifacts Reference build : https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc-- master-thumb_m3_softfp_eabi-build/517/artifact/artifacts
Instruction to reproduce the build : https://gitlab.com/LinaroLtd/ tcwg/ci/interesting-commits/-/raw/master/gcc/sha1/ c440b585ba374b6348ef223e4891a717a1f6660c/tcwg_gnu_embed_check_gcc/ master-thumb_m3_softfp_eabi/reproduction_instructions.txt
Full commit : See in git+ssh://linaroci@gcc.gnu.org/git/gcc.git
On Tue, 9 Sept 2025 at 11:27, Luc Grosheintz via Gcc-regression gcc-regression@gcc.gnu.org wrote:
Jonathan Wakely already fixed it. Please ignore the rest.
Thanks for letting us know.
Christophe
On 9/9/25 11:16 AM, Luc Grosheintz wrote:
I'd like to apologize for causing these regressions. Below I've copied out the relevant parts from the logs. To me it looks like _Xv is a reserved identifier.
I'll prepare a patch to fix the issue.
On 9/9/25 6:54 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 arm-eabi cortex-m3 softfp, after: | commit gcc-16-3649-gc440b585ba3 | Author: Luc Grosheintz luc.grosheintz@gmail.com | Date: Thu Sep 4 14:20:28 2025 +0200 | | libstdc++: Implement constant_wrapper, cw from P2781R9. | | This is a partial implementation of P2781R9. It adds std::cw and | std::constant_wrapper, but doesn't modify __integral_constant_like for | span/mdspan. | ... 25 lines of the commit log omitted.
Produces 4 regressions: | | regressions.sum: | Running g++:g++.old-deja/old-deja.exp ... | FAIL: g++.old-deja/g++.robertl/eb39.C -std=c++26 (test for excess errors)
Code: 4651: template<_CwFixedValue _Xv, typename> 4652: struct constant_wrapper : _CwOperators 4653: {
Compiler error: /home/tcwg-buildslave/workspace/tcwg_gnu_0/abe/builds/x86_64-pc-linux- gnu/arm-eabi/gcc-gcc.git~master-stage2/arm-eabi/libstdc++-v3/include/ type_traits:4651:26: error: expected '>' before numeric constant
My guess is that _Xv is a reserved name. It's not on the list of common bad identifiers [1], but it's the only guess I have.
| FAIL: g++.old-deja/g++.robertl/eb54.C -std=c++26 (test for excess errors)
Same as above.
| UNRESOLVED: g++.old-deja/g++.robertl/eb54.C -std=c++26 compilation failed to produce executable
Same as above.
| FAIL: g++.old-deja/g++.warn/iomanip.C -std=gnu++26 (test for excess errors)
Same as above.
Used configuration : *CI config* tcwg_gnu_embed_check_gcc arm-eabi -mthumb -march=armv7-m -mtune=cortex-m3 -mfloat-abi=softfp -mfpu=auto *configure and test flags:* --target arm-eabi --disable-multilib -- with-mode=thumb --with-cpu=cortex-m3 --with-float=softfp -- target_board=-mthumb/-march=armv7-m/-mtune=cortex-m3/-mfloat- abi=softfp/-mfpu=auto qemu_cpu=cortex-m3
We track this bug report under https://linaro.atlassian.net/browse/ GNU-1676. 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.
-----------------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
thumb_m3_softfp_eabi-build/518/artifact/artifacts/00-sumfiles/ The full lists of regressions and improvements as well as configure and make commands are in
thumb_m3_softfp_eabi-build/518/artifact/artifacts/notify/ The list of [ignored] baseline and flaky failures are in
thumb_m3_softfp_eabi-build/518/artifact/artifacts/sumfiles/xfails.xfail
Current build : https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc-- master-thumb_m3_softfp_eabi-build/518/artifact/artifacts Reference build : https://ci.linaro.org/job/tcwg_gnu_embed_check_gcc-- master-thumb_m3_softfp_eabi-build/517/artifact/artifacts
Instruction to reproduce the build : https://gitlab.com/LinaroLtd/ tcwg/ci/interesting-commits/-/raw/master/gcc/sha1/ c440b585ba374b6348ef223e4891a717a1f6660c/tcwg_gnu_embed_check_gcc/ master-thumb_m3_softfp_eabi/reproduction_instructions.txt
Full commit : See in git+ssh://linaroci@gcc.gnu.org/git/gcc.git
linaro-toolchain@lists.linaro.org
-
Christophe Lyon -
Luc Grosheintz