Bug#994169: xsimd: debci tests fail on generic i386 (warning sent to stderr?)

[Drew Parsons]

Source: xsimd
Version: 7.5.0-1
Severity: normal

The i386 arch corresponds to 686, i.e.  Pentium 6 (P6) released in 1995,
https://en.wikipedia.org/wiki/P6_(microarchitecture)

xsimd provides acceleration through extensions SSE2 and higher.

SSE2 was introduced with the Pentium 4 in 2000 (SSE came the previous
year with Pentium III).

What this means is that generic i386 does not have the instructions
that xsimd takes advantage of, so it's a no-op. xsimd provides no
generic advantage.

That doesn't mean xsimd should not be packaged for i386.  It uses
build-time guards (xsimd being header-only), so xsimd i386 might be
useful for users specifically developing applications for cheap
Pentium 4 chips (e.g. embedded device products).

But it does mean that xsimd is failing debci tests on i386 with the
message
"#warning "No SIMD instructions set detected, using fallback mode."

It's just a warning, not an error. It informs that xsimd will run in
no-op mode.

I gather the warning is being sent to stderr, which debci treats as an
error.  In that case the debci test can probably "pass" if
debian/tests/control adds 

 Restrictions: allow-stderr



-- System Information:
Debian Release: bookworm/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.10.0-8-amd64 (SMP w/8 CPU threads)
Kernel taint flags: TAINT_OOT_MODULE
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_AU:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled