Re: [Linaro-TCWG-CI] gcc-16-3649-gc440b585ba3: 4 regressions on master-thumb_m3_softfp_eabi

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, [email protected] 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 <[email protected]>
>>    | 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- 
>> [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_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://[email protected]/git/gcc.git
>