[Debian-med-packaging] Bug#1120614: Proposed fix — update bundled Eigen to 3.4.0

[Trupti]

On 2025-11-13 15:27, Trupti wrote:
> On 2025-11-13 14:56, Trupti wrote:
>> Package: src:arb
>> Version: 6.0.6-8
>> Severity: serious
>> Tags: ftbfs forky sid
>> X-Debbugs-Cc: debian-powerpc at lists.debian.org
>> User: debian-powerpc at lists.debian.org
>> Usertags: ppc64el
>> 
>> 
>> Dear maintainer,
>> 
>> arb FTBFS on ppc64el with below error:
>> 
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h: In
>> function 'typename Eigen::ei_packet_traits<T>::type
>> Eigen::ei_pset1(const Scalar&) [with Scalar = float; typename
>> ei_packet_traits<T>::type = __vector(4) float]':
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:194:40:
>> error: declaration does not declare anything [-fpermissive]
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:194:3:
>> error: expected primary-expression before 'float'
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:195:3:
>> error: 'af' was not declared in this scope
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:196:18:
>> error: invalid parameter combination for AltiVec intrinsic
>> '__builtin_vec_ld'
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h: In
>> function 'typename Eigen::ei_packet_traits<T>::type
>> Eigen::ei_pset1(const Scalar&) [with Scalar = int; typename
>> ei_packet_traits<T>::type = __vector(4) int]':
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:203:38:
>> error: declaration does not declare anything [-fpermissive]
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:203:3:
>> error: expected primary-expression before 'int'
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:204:3:
>> error: 'ai' was not declared in this scope
>> ../HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:205:18:
>> error: invalid parameter combination for AltiVec intrinsic
> 
> 
> Hello,
> 
> The ARB package FTBFS on ppc64el with GCC 14+ due to errors in the
> Altivec code from the bundled Eigen (eigen-2.0.16).
> The errors occur in
> HEADERLIBS/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h. These
> intrinsics are deprecated on little-endian PowerPC and now rejected by
> modern GCC.
> 
> 
> Upstream Eigen replaced these deprecated intrinsics with
> endian-agnostic equivalents starting around version 3.3.9
> Below is the commit of that change.
> https://gitlab.com/libeigen/eigen/-/commit/1615a2799384a2964d01ba77fe98e3f6fcc412f4
> 
> ARB currently bundles an older Eigen (eigen-2.0.16) which predates 
> those fixes.
> 
> 
> Thanks,
> Trupti.


Hi,

I tested the build failure on ppc64el and confirmed it is caused by the 
outdated Eigen version(2.0.16) bundled in ARB.

Replacing the bundled Eigen with Eigen 3.4.0 resolves the issue.The 
updated version already includes endian-safe Altivec intrinsics that 
compile correctly on ppc64el.

I tested a fix by updating the bundled Eigen to version 3.4.0 and 
adjusting one source file (`RNACMA/Cma.cxx`) for Eigen3 API 
compatibility. The package now resolves the issue of Altivec code on 
ppc64el.

A proposed patch is attached for review.

Changes summary:
   • Update HEADERLIBS/Makefile to unpack Eigen 3.4.0.
   • Add HEADERLIBS/eigen to CC_INCLUDES in Makefile.
   • Update RNACMA/Cma.cxx to match Eigen 3 API.


Please review and consider applying this patch.






Note :
After resolving this issue also arb pacakge is FTBFS on ppc64el with 
different errors. Which will be taken care by  bug number (#1114476).

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1114476 bug report.


Thanks,
Trupti.
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