xsimd tests (CHECK_UNARY) are now failing with release 14.2.0 on
ppc64el architecture with gcc 15.2.0.
https://ci.debian.net/packages/x/xsimd/unstable/ppc64el/71330067/
https://ci.debian.net/packages/x/xsimd/testing/ppc64el/71345568/

The gcc tests were passing with 14.1.0,
https://ci.debian.net/packages/x/xsimd/unstable/ppc64el/70780399/
https://ci.debian.net/packages/x/xsimd/testing/ppc64el/71221930/

Ironically ppc64el previously failed tests with clang, Issue #999 ,
but that is now fixed in 14.2.0 by PR #1010 and  PR #1337.
So 14.2.0 now passes on ppc64el with clang 21.1.8, while failing with
gcc 15.2.0.

Does it mean upstream PR#1337, while fixing clang builds, has
interfered with gcc builds?

Reported upstream, Issue#1356